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Sample records for simultaneous sensitive determination

  1. Single-acquisition method for simultaneous determination of extrinsic gamma-camera sensitivity and spatial resolution

    Energy Technology Data Exchange (ETDEWEB)

    Santos, J.A.M. [Servico de Fisica Medica, Instituto Portugues de Oncologia Francisco Gentil do Porto, E.P.E., Rua Dr. Antonio Bernardino de Almeida, 4200-072 Porto (Portugal)], E-mail: a.miranda@portugalmail.pt; Sarmento, S. [Servico de Fisica Medica, Instituto Portugues de Oncologia Francisco Gentil do Porto, E.P.E., Rua Dr. Antonio Bernardino de Almeida, 4200-072 Porto (Portugal); Alves, P.; Torres, M.C. [Departamento de Fisica da Universidade do Porto, Rua do Campo Alegre 687, 4169-007 Porto (Portugal); Bastos, A.L. [Servico de Medicina Nuclear, Instituto Portugues de Oncologia Francisco Gentil do Porto, E.P.E., Rua Dr. Antonio Bernardino de Almeida, 4200-072 Porto (Portugal); Ponte, F. [Servico de Fisica Medica, Instituto Portugues de Oncologia Francisco Gentil do Porto, E.P.E., Rua Dr. Antonio Bernardino de Almeida, 4200-072 Porto (Portugal)

    2008-01-15

    A new method for measuring simultaneously both the extrinsic sensitivity and spatial resolution of a gamma-camera in a single planar acquisition was implemented. A dual-purpose phantom (SR phantom; sensitivity/resolution) was developed, tested and the results compared with other conventional methods used for separate determination of these two important image quality parameters. The SR phantom yielded reproducible and accurate results, allowing an immediate visual inspection of the spatial resolution as well as the quantitative determination of the contrast for six different spatial frequencies. It also proved to be useful in the estimation of the modulation transfer function (MTF) of the image formation collimator/detector system at six different frequencies and can be used to estimate the spatial resolution as function of the direction relative to the digital matrix of the detector.

  2. Sensitive double-antibody method for simultaneous determination of insulin and growth hormone

    International Nuclear Information System (INIS)

    Koparanova, O.; Sotirov, G.; Tyrkolev, N.

    1982-01-01

    A method is described for simultaneous determination of insulin and growth hormone in one sample, using double-antibody technique. The method is characterized by appreciable sensitivity (2.5 μE/ml for insulin and a.2 ng/ml for growth hormone), exactness (variation quotient 6-16 per cent) and reproducibility (96.9-117 per cent). There was no statistically significant difference in the insulin and growth hormone values of the same sera, determined by the here suggested and the standard methods. The necessary test material for examination of either hormone is minimal (0.2 ml). One may thus extend the possibilities for radioimmunologic determination of insulin and growth hormone, when only minor amounts of serum or other biological fluid are available. The method is also less time consuming. Results are reported of statistical processing of an experimental model and different sera determined by the standard method and the one described by the authors. (author)

  3. Simultaneous and sensitive LC-MS/MS determination of tetrahydrocannabinol and metabolites in human plasma.

    Science.gov (United States)

    Ferreirós, N; Labocha, S; Walter, C; Lötsch, J; Geisslinger, G

    2013-02-01

    Cannabis is not only a widely used illicit drug but also a substance which can be used in pharmacological therapy because of its analgesic, antiemetic, and antispasmodic properties. A very rapid and sensitive method for determination of ∆(9)-tetrahydrocannabinol (THC), the principal active component of cannabis, and two of its phase I metabolites in plasma has been developed and validated. After solid-phase extraction of plasma (0.2 mL), the clean extracts were analyzed by tandem mass spectrometry after a 5-min liquid chromatographic separation. The linear calibration ranges were from 0.05 to 30 ng mL(-1) for THC and 11-nor-∆(9)-carboxy-tetrahydrocannabinol (THC-COOH) and from 0.2 to 30 ng mL(-1) for ∆(9)-(11-OH)-tetrahydrocannabinol (11-OH-THC). Imprecision and inaccuracy were always below 7 and 12 % (expressed as relative standard deviation and relative error), respectively. The method has been successfully applied to determination of the three analytes in plasma obtained from healthy volunteers after oral administration of 20 mg dronabinol.

  4. High sensitive and selective HPTLC method assisted by digital image processing for simultaneous determination of catecholamines and related drugs.

    Science.gov (United States)

    Sima Tuhuţiu, Ioana Anamaria; Casoni, Dorina; Sârbu, Costel

    2013-09-30

    A highly sensitive and selective thin layer chromatographic (TLC) method was developed for simultaneous determination of catecholamines and their related drugs using a new detection method and digital image processing of chromatographic plates. For the quantitative evaluation of the investigated compounds, the chromatographic separation was followed by spraying the plate with 0.02% solution of 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) in ethanol. The BioDit Thin Layer Chromatography (TLC) Scanner device and advanced specific software (ImageDecipher-TLC, Sorbfil TLC Videodensitometer and JustTLC) were used for the detection and quantification of chromatographic spots. For an accurate determination, the RGB colored images of the bright-white spots detected against a purple background were inverted and processed after their conversion into green scale. The results showed a strongly linear correlation between area (R(2)>0.99) and volume (R(2)>0.99) of spots and concentration of investigated compounds in all cases. The limit of detection (LOD) and the limit of quantification (LOQ) were below 49.3 ng/spot and 69.6 ng/spot respectively in all cases. The evaluation of the method was performed using different pharmaceutical samples spiked with the investigated amines and validated with respect to accuracy and precision. Copyright © 2013 Elsevier B.V. All rights reserved.

  5. Liquid-phase exfoliated graphene as highly-sensitive sensor for simultaneous determination of endocrine disruptors: Diethylstilbestrol and estradiol

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Lintong; Cheng, Qin [Key Laboratory for Large-Format Battery Materials and System, Ministry of Education, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China); Chen, Danchao; Ma, Ming [Ningbo Entry-exit Inspection and Quarantine Bureau of China, Ningbo 315012 (China); Wu, Kangbing, E-mail: kbwu@hust.edu.cn [Key Laboratory for Large-Format Battery Materials and System, Ministry of Education, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China)

    2015-02-11

    Graphical abstract: - Highlights: • A novel electrochemical sensor was developed for diethylstilbestrol and estradiol. • Graphene prepared by solvent exfoliation greatly enhances the detection sensitivity. • The newly-developed method has promising application and the accuracy is good. - Abstract: It is quite important to develop convenient and rapid analytical methods for trace levels of endocrine disruptors because they heavily affect health and reproduction of humans and animals. Herein, graphene was easily prepared via one-step exfoliation using N-methyl-2-pyrrolidone as solvent, and then used to construct an electrochemical sensor for highly-sensitive detection of diethylstilbestrol (DES) and estradiol (E2). On the surface of prepared graphene film, two independent and greatly-increased oxidation waves were observed at 0.28 V and 0.49 V for DES and E2. The remarkable signal enlargements indicated that the detection sensitivity was improved significantly. The influences of pH value, amount of graphene and accumulation time on the oxidation signals of DES and E2 were discussed. As a result, a highly-sensitive and rapid electrochemical method was newly developed for simultaneous detection of DES and E2. The values of detection limit were evaluated to be 10.87 nM and 4.9 nM for DES and E2. Additionally, this new method was successfully used in lake water samples and the accuracy was satisfactory.

  6. Liquid-phase exfoliated graphene as highly-sensitive sensor for simultaneous determination of endocrine disruptors: diethylstilbestrol and estradiol.

    Science.gov (United States)

    Hu, Lintong; Cheng, Qin; Chen, Danchao; Ma, Ming; Wu, Kangbing

    2015-01-01

    It is quite important to develop convenient and rapid analytical methods for trace levels of endocrine disruptors because they heavily affect health and reproduction of humans and animals. Herein, graphene was easily prepared via one-step exfoliation using N-methyl-2-pyrrolidone as solvent, and then used to construct an electrochemical sensor for highly-sensitive detection of diethylstilbestrol (DES) and estradiol (E2). On the surface of prepared graphene film, two independent and greatly-increased oxidation waves were observed at 0.28V and 0.49V for DES and E2. The remarkable signal enlargements indicated that the detection sensitivity was improved significantly. The influences of pH value, amount of graphene and accumulation time on the oxidation signals of DES and E2 were discussed. As a result, a highly-sensitive and rapid electrochemical method was newly developed for simultaneous detection of DES and E2. The values of detection limit were evaluated to be 10.87 nM and 4.9 nM for DES and E2. Additionally, this new method was successfully used in lake water samples and the accuracy was satisfactory. Copyright © 2014 Elsevier B.V. All rights reserved.

  7. A New Sensitive Sensor for Simultaneous Differential Pulse Voltammetric Determination of Codeine and Acetaminophen Using a Hydroquinone Derivative and Multiwall Carbon Nanotubes Carbon Paste Electrode

    Directory of Open Access Journals (Sweden)

    Elahe Garazhian

    2015-01-01

    Full Text Available A new sensitive sensor was fabricated for simultaneous determination of codeine and acetaminophen based on 4-hydroxy-2-(triphenylphosphoniophenolate (HTP and multiwall carbon nanotubes paste electrode at trace levels. The sensitivity of codeine determination was deeply affected by spiking multiwall carbon nanotubes and a modifier in carbon paste. Electron transfer coefficient, α, catalytic electron rate constant, k, and the exchange current density, j0, for oxidation of codeine at the HTP-MWCNT-CPE were calculated using cyclic voltammetry. The calibration curve was linear over the range 0.2–844.7 μM with two linear segments, and the detection limit of 0.063 μM of codeine was obtained using differential pulse voltammetry. The modified electrode was separated codeine and acetaminophen signals by differential pulse voltammetry. The modified electrode was applied for the determination of codeine and acetaminophen in biological and pharmaceutical samples with satisfactory results.

  8. Sensitive electrochemical sensors for simultaneous determination of ascorbic acid, dopamine, and uric acid based on Au@Pd-reduced graphene oxide nanocomposites

    Science.gov (United States)

    Jiang, Jingjing; Du, Xuezhong

    2014-09-01

    Sensitive electrochemical sensors were fabricated with reduced graphene oxide-supported Au@Pd (Au@Pd-RGO) nanocomposites by one-step synthesis for individual and simultaneous determination of ascorbic acid (AA), dopamine (DA), and uric acid (UA) with low detection limits and wide concentration ranges. From the Au@Pd-RGO-modified electrodes, well-separated oxidation peaks and enhanced peak currents of AA, DA, and UA were observed owing to the superior conductivity of RGO and the excellent catalytic activity of Au@Pd nanoparticles. For individual detection, the linear responses of AA, DA, and UA were in the concentration ranges of 0.1-1000, 0.01-100, and 0.02-500 μM with detection limits of 0.02, 0.002, and 0.005 μM (S/N = 3), respectively. For simultaneous detection by synchronous change of the concentrations of AA, DA, and UA, the linear response ranges were 1-800, 0.1-100, and 0.1-350 μM with detection limits of 0.28, 0.024, and 0.02 μM (S/N = 3), respectively. The fabricated sensors were further applied to the detection of AA, DA, and UA in urine samples. The Au@Pd-RGO nanocomposites have promising applications in highly sensitive and selective electrochemical sensing.Sensitive electrochemical sensors were fabricated with reduced graphene oxide-supported Au@Pd (Au@Pd-RGO) nanocomposites by one-step synthesis for individual and simultaneous determination of ascorbic acid (AA), dopamine (DA), and uric acid (UA) with low detection limits and wide concentration ranges. From the Au@Pd-RGO-modified electrodes, well-separated oxidation peaks and enhanced peak currents of AA, DA, and UA were observed owing to the superior conductivity of RGO and the excellent catalytic activity of Au@Pd nanoparticles. For individual detection, the linear responses of AA, DA, and UA were in the concentration ranges of 0.1-1000, 0.01-100, and 0.02-500 μM with detection limits of 0.02, 0.002, and 0.005 μM (S/N = 3), respectively. For simultaneous detection by synchronous change of the

  9. Development and validation of a selective, sensitive and stability indicating UPLC-MS/MS method for rapid, simultaneous determination of six process related impurities in darunavir drug substance.

    Science.gov (United States)

    A, Vijaya Bhaskar Reddy; Yusop, Zulkifli; Jaafar, Jafariah; Aris, Azmi B; Majid, Zaiton A; Umar, Khalid; Talib, Juhaizah

    2016-09-05

    In this study a sensitive and selective gradient reverse phase UPLC-MS/MS method was developed for the simultaneous determination of six process related impurities viz., Imp-I, Imp-II, Imp-III, Imp-IV, Imp-V and Imp-VI in darunavir. The chromatographic separation was performed on Acquity UPLC BEH C18 (50 mm×2.1mm, 1.7μm) column using gradient elution of acetonitrile-methanol (80:20, v/v) and 5.0mM ammonium acetate containing 0.01% formic acid at a flow rate of 0.4mL/min. Both negative and positive electrospray ionization (ESI) modes were operated simultaneously using multiple reaction monitoring (MRM) for the quantification of all six impurities in darunavir. The developed method was fully validated following ICH guidelines with respect to specificity, linearity, limit of detection (LOD), limit of quantification (LOQ), accuracy, precision, robustness and sample solution stability. The method was able to quantitate Imp-I, Imp-IV, Imp-V at 0.3ppm and Imp-II, Imp-III, and Imp-VI at 0.2ppm with respect to 5.0mg/mL of darunavir. The calibration curves showed good linearity over the concentration range of LOQ to 250% for all six impurities. The correlation coefficient obtained was >0.9989 in all the cases. The accuracy of the method lies between 89.90% and 104.60% for all six impurities. Finally, the method has been successfully applied for three formulation batches of darunavir to determine the above mentioned impurities, however no impurity was found beyond the LOQ. This method is a good quality control tool for the trace level quantification of six process related impurities in darunavir during its synthesis. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. Electrodeposited nitrogen-doped graphene/carbon nanotubes nanocomposite as enhancer for simultaneous and sensitive voltammetric determination of caffeine and vanillin

    International Nuclear Information System (INIS)

    Jiang, Lin; Ding, Yaping; Jiang, Feng; Li, Li; Mo, Fan

    2014-01-01

    Graphical abstract: A nanocomposite of nitrogen-doped graphene (NGR) and nitrogen-doped carbon nanotubes (NCNTs) was first modified onto an electrode through electrodeposition method and employed to sensitively detect caffeine and vanillin simultaneously for the first time. - Highlights: • The first electrochemical sensor for caffeine (CAF) and vanillin (VAN). • NGR–NCNTs was modified through electrodeposition for the first time. • The sensor was qualified for real sample determination with satisfactory results. - Abstract: A nitrogen-doped graphene/carbon nanotubes (NGR–NCNTs) nanocomposite was employed into the study of the electrochemical sensor via electrodeposition for the first time. The morphology and structure of NGR–NCNTs nanocomposite were investigated by scanning electron microscopy (SEM) and transmission electron microscopy (TEM), respectively. Meanwhile, the electrochemical performance of the glassy carbon electrode (GCE) modified with electrodeposited NGR–NCNTs (ENGR–NCNTs/GCE) towards caffeine (CAF) and vanillin (VAN) determination was demonstrated by cyclic voltammetry (CV) and square wave voltammetry (SWV). Under optimal condition, ENGR–NCNTs/GCE exhibited a wide linearity of 0.06–50 μM for CAF and 0.01–10 μM for VAN with detection limits of 0.02 μM and 3.3 × 10 −3 μM, respectively. Furthermore, the application of the proposed sensor in food products was proven to be practical and reliable. The desirable results show that the ENGR–NCNTs nanocomposite has promising potential in electrocatalytic biosensor application

  11. Electrodeposited nitrogen-doped graphene/carbon nanotubes nanocomposite as enhancer for simultaneous and sensitive voltammetric determination of caffeine and vanillin

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Lin; Ding, Yaping, E-mail: wdingyp@sina.com; Jiang, Feng; Li, Li; Mo, Fan

    2014-06-23

    Graphical abstract: A nanocomposite of nitrogen-doped graphene (NGR) and nitrogen-doped carbon nanotubes (NCNTs) was first modified onto an electrode through electrodeposition method and employed to sensitively detect caffeine and vanillin simultaneously for the first time. - Highlights: • The first electrochemical sensor for caffeine (CAF) and vanillin (VAN). • NGR–NCNTs was modified through electrodeposition for the first time. • The sensor was qualified for real sample determination with satisfactory results. - Abstract: A nitrogen-doped graphene/carbon nanotubes (NGR–NCNTs) nanocomposite was employed into the study of the electrochemical sensor via electrodeposition for the first time. The morphology and structure of NGR–NCNTs nanocomposite were investigated by scanning electron microscopy (SEM) and transmission electron microscopy (TEM), respectively. Meanwhile, the electrochemical performance of the glassy carbon electrode (GCE) modified with electrodeposited NGR–NCNTs (ENGR–NCNTs/GCE) towards caffeine (CAF) and vanillin (VAN) determination was demonstrated by cyclic voltammetry (CV) and square wave voltammetry (SWV). Under optimal condition, ENGR–NCNTs/GCE exhibited a wide linearity of 0.06–50 μM for CAF and 0.01–10 μM for VAN with detection limits of 0.02 μM and 3.3 × 10{sup −3} μM, respectively. Furthermore, the application of the proposed sensor in food products was proven to be practical and reliable. The desirable results show that the ENGR–NCNTs nanocomposite has promising potential in electrocatalytic biosensor application.

  12. Simple, cost-effective and sensitive liquid chromatography diode array detector method for simultaneous determination of eight sulfonylurea herbicides in soya milk samples.

    Science.gov (United States)

    Rejczak, Tomasz; Tuzimski, Tomasz

    2016-11-18

    In this study authors propose a simple, cost-effective and sensitive liquid chromatography diode array detector (HPLC-DAD) method for the simultaneous determination of eight sulfonylurea herbicides (oxasulfuron, metsulfuron-methyl, triasulfuron, rimsulfuron, chlorsulfuron, mesosulfuron-methyl, amidosulfuron and bensulfuron-methyl) in soya milk samples. QuEChERS-based extraction procedure presents good performance for all of the analytes with recoveries in the range of 61-108% and relative standard deviations (RSD%) less than 15%. No significant matrix effect was observed thanks to application of effective zirconium-dioxide based sorbent (Z-Sep). Method LOQs for all investigated analytes were set at satisfactory low value of 10ngmL -1 of food product. The procedure was evaluated in terms of natural samples analysis. Chlorsulfuron was determined at concentration of 14.2ngmL -1 of soya milk product, which was qualitatively confirmed via LC coupled with tandem mass spectrometry (LC-MS/MS). The most important steps of procedure optimization are presented. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Simultaneous determination of amino acid and monoamine neurotransmitters in PC12 cells and rats models of Parkinson's disease using a sensitizing derivatization reagent by UHPLC-MS/MS.

    Science.gov (United States)

    Zhao, Xian-En; Zhu, Shuyun; Yang, Hongmei; You, Jinmao; Song, Fengrui; Liu, Zhiqiang; Liu, Shuying

    2015-07-15

    Multi-analytes simultaneous monitoring of amino acid and monoamine neurotransmitters (NTs) has important scientific significance for their related pathology, physiology and drug screening. In this work, in virtue of a mass spectrometry sensitizing reagent 10-ethyl-acridone-3-sulfonyl chloride (EASC) as derivatization reagent, an Ultra High Performance Liquid Chromatography-Tandem Mass Spectrometry (UHPLC-MS/MS) method was developed and validated for simultaneous determination of six amino acid NTs, two monoamine ones and its one metabolite. The simple and rapid derivatization reaction was innovatively combined with plasma preparation by using EASC acetonitrile solution as protein precipitant. This interesting combination brought the advantages of speediness, simpleness and high-throughput in a cost-effective way. Under the optimized conditions, LODs (0.004-3.80nM) and LOQs (0.014-13.3nM) of EASC derivatized-NTs were calculated and found to be significantly lower than those of direct UHPLC-MS/MS detection about 11.5-275.0 and 14.4-371.4 times, respectively. Moreover, EASC derivatization significantly improved chromatographic resolution and matrix effect when compared with direct UPLC-MS/MS detection method without derivatization. Meanwhile, it also brought acceptable precision (3.0-13.0%, peak area CVs%), accuracy (86.4-112.9%), recovery (88.3-107.8%) and stability (3.8-8.5%, peak area CVs%) results. This method was successfully applied for the antiparkinsonian effect evaluation of levodopa and Ginsenoside Rg1 using PC12 cells and rats models by measuring multiple NTs. This provided a new method for the NTs related studies in the future. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. Development of a simple and sensitive HPLC-UV method for the simultaneous determination of cannabidiol and Δ(9)-tetrahydrocannabinol in rat plasma.

    Science.gov (United States)

    Zgair, Atheer; Wong, Jonathan C M; Sabri, Akmal; Fischer, Peter M; Barrett, David A; Constantinescu, Cris S; Gershkovich, Pavel

    2015-10-10

    There has been increased interest in the medical use of cannabinoids in recent years, particularly in the predominant natural cannabinoids, cannabidiol (CBD) and Δ(9)-tetrahydrocannabinol (THC). The aim of the current study was to develop a sensitive and reliable method for the quantification of CBD and THC in rat plasma. A combination of protein precipitation using cold acetonitrile and liquid-liquid extraction using n-hexane was utilised to extract CBD and THC from rat plasma. Samples were then evaporated and reconstituted in acetonitrile and 30 μL was injected into an HPLC system. Separation was achieved using an ACE C18-PFP 150 mm × 4.6 mm, 3 μm column at 55 °C with isocratic elution using a mobile phase consisting of acetonitrile-water (62:38, v/v) at 1 mL/min for 20 min. Both cannabinoids, as well as the internal standard (4,4-dichlorodiphenyltrichloroethane, DDT) were detected at 220 nm. Our new method showed linearity in the range of 10-10,000 ng/mL and a lower limit of quantification (LLOQ) of 10 ng/mL for both cannabinoids, which is comparable to previously reported LC-MS/MS methods. Inter- and intra-day precision and accuracy were below 15% RSD and RE, respectively. To demonstrate the suitability of the method for in vivo studies in rats, the assay was applied to a preliminary pharmacokinetic study following IV bolus administration of 5 mg/kg CBD or THC. In conclusion, a simple, sensitive, and cost-efficient HPLC-UV method for the simultaneous determination of CBD and THC has been successfully developed, validated and applied to a pharmacokinetic study in rats. Copyright © 2015 Elsevier B.V. All rights reserved.

  15. Sensitive Deep-Sequencing-Based HIV-1 Genotyping Assay To Simultaneously Determine Susceptibility to Protease, Reverse Transcriptase, Integrase, and Maturation Inhibitors, as Well as HIV-1 Coreceptor Tropism

    Science.gov (United States)

    Gibson, Richard M.; Meyer, Ashley M.; Winner, Dane; Archer, John; Feyertag, Felix; Ruiz-Mateos, Ezequiel; Leal, Manuel; Robertson, David L.; Schmotzer, Christine L.

    2014-01-01

    With 29 individual antiretroviral drugs available from six classes that are approved for the treatment of HIV-1 infection, a combination of different phenotypic and genotypic tests is currently needed to monitor HIV-infected individuals. In this study, we developed a novel HIV-1 genotypic assay based on deep sequencing (DeepGen HIV) to simultaneously assess HIV-1 susceptibilities to all drugs targeting the three viral enzymes and to predict HIV-1 coreceptor tropism. Patient-derived gag-p2/NCp7/p1/p6/pol-PR/RT/IN- and env-C2V3 PCR products were sequenced using the Ion Torrent Personal Genome Machine. Reads spanning the 3′ end of the Gag, protease (PR), reverse transcriptase (RT), integrase (IN), and V3 regions were extracted, truncated, translated, and assembled for genotype and HIV-1 coreceptor tropism determination. DeepGen HIV consistently detected both minority drug-resistant viruses and non-R5 HIV-1 variants from clinical specimens with viral loads of ≥1,000 copies/ml and from B and non-B subtypes. Additional mutations associated with resistance to PR, RT, and IN inhibitors, previously undetected by standard (Sanger) population sequencing, were reliably identified at frequencies as low as 1%. DeepGen HIV results correlated with phenotypic (original Trofile, 92%; enhanced-sensitivity Trofile assay [ESTA], 80%; TROCAI, 81%; and VeriTrop, 80%) and genotypic (population sequencing/Geno2Pheno with a 10% false-positive rate [FPR], 84%) HIV-1 tropism test results. DeepGen HIV (83%) and Trofile (85%) showed similar concordances with the clinical response following an 8-day course of maraviroc monotherapy (MCT). In summary, this novel all-inclusive HIV-1 genotypic and coreceptor tropism assay, based on deep sequencing of the PR, RT, IN, and V3 regions, permits simultaneous multiplex detection of low-level drug-resistant and/or non-R5 viruses in up to 96 clinical samples. This comprehensive test, the first of its class, will be instrumental in the development of new

  16. A sensitive liquid chromatography-mass spectrometry method for simultaneous determination of two active chromones from Saposhnikovia root in rat plasma and urine.

    Science.gov (United States)

    Dai, Jinna; Chen, Xiaohui; Cheng, Weiming; Liu, Xiao; Fan, Xue; Shen, Zhenduo; Bi, Kaishun

    2008-06-01

    A sensitive and efficient liquid chromatography-mass spectrometry method was developed and validated for the simultaneous determination of two active chromones (prim-O-glucosylcimifugin and 4'-O-D-glucosyl-5-O-methylvisamminol) from Saposhnikovia root in rat plasma and urine. The plasma or urine samples were prepared by protein precipitation. Chromatographic separation of the two active chromones from matrix interferences was achieved on an Angilent TC-C(18) column with a mobile phase consisted of methanol, water and 0.1% formic acid. Puerarin was added as the internal standard. The method was validated with the concentration range 1.0-100 ng/mL in rat plasma and 10-1000 ng/mL in urine for prim-O-glucosylcimifugin, 1.5-150 ng/mL in plasma and 15-1500 ng/mL in urine for 4'-O-D-glucosyl-5-O-methylvisamminol. The lower limit of quantitation (LLOQ) of prim-O-glucosylcimifugin and 4'-O-D-glucosyl-5-O-methylvisamminol was 1.0 and 1.5 ng/mL in plasma, 10 and 15 ng/mL in urine, respectively. The intra- and inter-day precision across three validation days over the entire concentration range was lower than 9.0% as terms of relative standard deviation (R.S.D.). Accuracy determined at three quality control concentrations (2.0, 25 and 75 ng/mL for prim-O-glucosylcimifugin; 3.0, 37.5 and 112.5 ng/mL for 4'-O-D-glucosyl-5-O-methylvisamminol) ranged from -1.9 to 3.9% as terms of relative error (R.E.). The LC-ESI-MS method was further applied to assess pharmacokinetics and urine excretion of the two chromones after oral administration of Fangfeng extract to rats. Practical utility of this new LC-MS method was confirmed in pilot pharmacokinetic studies in rats following oral administration.

  17. Simultaneous Determination of Famotidine and Flurbiprofen by High ...

    African Journals Online (AJOL)

    Purpose: To develop a selective, sensitive and accurate simultaneous High Performance Liquid. Chromatography (HPLC) method for the analysis of flurbiprofen and famotidine tablet dosage form and excipients. Methods: A simultaneous method for the determination of the two drugs was employed. The assay consisted of ...

  18. Simultaneous Determination of Famotidine and Flurbiprofen by High ...

    African Journals Online (AJOL)

    Purpose: To develop a selective, sensitive and accurate simultaneous High Performance Liquid Chromatography (HPLC) method for the analysis of flurbiprofen and famotidine tablet dosage form and excipients. Methods: A simultaneous method for the determination of the two drugs was employed. The assay consisted of ...

  19. A sensitive HPLC-MS method for simultaneous determination of thirteen components in rat plasma and its application to pharmacokinetic study of Tanreqing injection.

    Science.gov (United States)

    Feng, Su-Xiang; Li, Xian-He; Wang, Meng-Meng; Hao, Rui; Li, Meng-Meng; Zhang, Lei; Wang, Zhe

    2018-01-30

    A rapid, sensitive and selective method based on high-performance liquid chromatography coupled with Q-Exactive mass spectrometry was developed and validated for simultaneous quantification of thirteen components in rat plasma, including chlorogenic acid, 5-caffeoylquinic acid, 4-caffeoylquinic acid, luteoloside, isochlorogenic acid A, B and C, scutellarin, baicalin, wogonin, baicalein, phillyrin and forsythoside A. After precipitating proteins from the plasma samples with methanol, chromatographic separation of the thirteen components was achieved by using an XBridge™ C 18 column (2.1mm×150mm, 5μm) with the mobile phase consisting of methanol and 0.1% formic acid in water at a flow rate of 0.3mL/min. High-resolution MS quantification was adopted with detection on a Q-Exactive mass spectrometer in full-scan mode, and the results were obtained using a mass extraction window of 10ppm at a mass resolution of 70, 000. All the calibration curves exhibited good linearity (r 2 >0.991) over the measured ranges. The lower limit of quantitation (LLOQ) was in the range of 1.05-8.13ng/mL. The intra- and inter-day precision (RSD) was less than 11.70% and the accuracy (RE) ranged from -5.58% to 12.29%. No significant matrix effect was observed and the extraction recoveries of all the analytes were more than 79.36%. The developed method was applied to a pharmacokinetic study of the thirteen ingredients in rats after intravenous administration of Tanreqing at three doses of 3, 6 and 12mL/kg. The results indicated that 8 of the 13 components, isochlorogenic acid A, B and C, chlorogenic acid, baicalin, wogonin, luteoloside and forsythoside A, had linear pharmacokinetic properties in the tested dosage range. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Simultaneous Determination of Ciprofloxacin and Tinidazole in ...

    African Journals Online (AJOL)

    Purpose: To develop a simple, sensitive and specific liquid chromatographic method with PDA detection for the simultaneous estimation of ciprofloxacin and tinidazole in tablet dosage form. Methods: Separation was achieved with an Agilent XDB C18, 250 × 4.60 mm 5 μ column, low pressure gradient mode with a ambient ...

  1. Simultaneous determination of naproxen, ibuprofen and diclofenac ...

    African Journals Online (AJOL)

    Simultaneous determination of naproxen, ibuprofen and diclofenac in wastewater using solid-phase extraction with high performance liquid chromatography. ... The instrument quantification limits obtained were 0.1 μg·L-1, for naproxen and 0.4 μg·L-1 for both ibuprofen and diclofenac. The detected concentrations for ...

  2. Simultaneous Spectrophotometric Determination of Valsartan and ...

    African Journals Online (AJOL)

    Purpose: To develop a direct, simple and extraction-free spectrophotometric method for the simultaneous estimation of valsartan and ezetimibe in pharmaceuticals. Methods: A spectrophotometric method for the determination of valsartan and ezetimibe was developed using acidic dyes, namely, bromophenol blue (BPB) ...

  3. Simultaneous determination of isoniazid and pyrazinamide in ...

    African Journals Online (AJOL)

    Purpose: To develop and validate a new high performance liquid chromatographic (HPLC) method for the simultaneous determination of isoniazid (INH) and pyrazinamide (PZA) in plasma. Methods: A 150 μL aliquot of plasma was mixed with 75 μL of 10 % trichloroacetic acid containing 100 mg/L of acetanilide as the ...

  4. Simultaneous Determination of Seven Constituents in Herbal ...

    African Journals Online (AJOL)

    Simultaneous Determination of Seven Constituents in Herbal Prescription Jaeumganghwa-Tang Using HPLC-PDA. CS Seo, JH Kim, HK Shin. Abstract. A simple and accurate high-performance liquid chromatographic method was applied to the quantitative analysis of seven components of the traditional herbal prescription ...

  5. Electrodeposited nitrogen-doped graphene/carbon nanotubes nanocomposite as enhancer for simultaneous and sensitive voltammetric determination of caffeine and vanillin.

    Science.gov (United States)

    Jiang, Lin; Ding, Yaping; Jiang, Feng; Li, Li; Mo, Fan

    2014-06-23

    A nitrogen-doped graphene/carbon nanotubes (NGR-NCNTs) nanocomposite was employed into the study of the electrochemical sensor via electrodeposition for the first time. The morphology and structure of NGR-NCNTs nanocomposite were investigated by scanning electron microscopy (SEM) and transmission electron microscopy (TEM), respectively. Meanwhile, the electrochemical performance of the glassy carbon electrode (GCE) modified with electrodeposited NGR-NCNTs (ENGR-NCNTs/GCE) towards caffeine (CAF) and vanillin (VAN) determination was demonstrated by cyclic voltammetry (CV) and square wave voltammetry (SWV). Under optimal condition, ENGR-NCNTs/GCE exhibited a wide linearity of 0.06-50 μM for CAF and 0.01-10 μM for VAN with detection limits of 0.02 μM and 3.3×10(-3) μM, respectively. Furthermore, the application of the proposed sensor in food products was proven to be practical and reliable. The desirable results show that the ENGR-NCNTs nanocomposite has promising potential in electrocatalytic biosensor application. Copyright © 2014 Elsevier B.V. All rights reserved.

  6. Development and validation of a rapid, selective, and sensitive LC-MS/MS method for simultaneous determination of D- and L-amino acids in human serum: application to the study of hepatocellular carcinoma.

    Science.gov (United States)

    Han, Minlu; Xie, Mengyu; Han, Jun; Yuan, Daoyi; Yang, Tian; Xie, Ying

    2018-04-01

    A validated liquid chromatography-tandem mass spectrometry method was developed for the simultaneous determination of D- and L-amino acids in human serum. Under the optimum conditions, except for DL-proline, L-glutamine, and D-lysine, the enantioseparation of the other 19 enantiomeric pairs of proteinogenic amino acids and nonchiral glycine was achieved with a CROWNPAK CR-I(+) chiral column within 13 min. The lower limits of quantitation for L-amino acids (including glycine) and D-amino acids were 5-56.25 μM and 0.625-500 nM, respectively, in human serum. The intraday precision and interday precision for all the analytes were less than 15%, and the accuracy ranged from -12.84% to 12.37% at three quality control levels. The proposed method, exhibiting high rapidity, enantioresolution, and sensitivity, was successfully applied to the quantification of D- and L-amino acid levels in serum from hepatocellular carcinoma patients and healthy individuals. The serum concentrations of L-arginine, L-isoleucine, L-aspartate, L-tryptophan, L-alanine, L-methionine, L-serine, glycine, L-valine, L-leucine, L-phenylalanine, L-threonine, D-isoleucine, D-alanine, D-glutamate, D-glutamine, D-methionine, and D-threonine were significantly reduced in the hepatocellular carcinoma patients compared with the healthy individuals (P < 0.01). D-Glutamate and D-glutamine were identified as the most downregulated serum markers (fold change greater than 1.5), which deserves further attention in hepatocellular carcinoma research. Graphical abstract Simultaneous determination of D- and L-amino acids in human serum from hepatocellular carcinoma patients and healthy individuals. AA amino acid, HCC hepatocellular carcinoma, LC liquid chromatography, MS/MS tandem mass spectrometry, NC normal control, TIC total ion chromatogram.

  7. Simultaneous Mass Determination for Gravitationally Coupled Asteroids

    Energy Technology Data Exchange (ETDEWEB)

    Baer, James [Private address, 3210 Apache Road, Pittsburgh, PA 15241 (United States); Chesley, Steven R., E-mail: jimbaer1@earthlink.net [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States)

    2017-08-01

    The conventional least-squares asteroid mass determination algorithm allows us to solve for the mass of a large subject asteroid that is perturbing the trajectory of a smaller test asteroid. However, this algorithm is necessarily a first approximation, ignoring the possibility that the subject asteroid may itself be perturbed by the test asteroid, or that the encounter’s precise geometry may be entangled with encounters involving other asteroids. After reviewing the conventional algorithm, we use it to calculate the masses of 30 main-belt asteroids. Compared to our previous results, we find new mass estimates for eight asteroids (11 Parthenope, 27 Euterpe, 51 Neimausa, 76 Freia, 121 Hermione, 324 Bamberga, 476 Hedwig, and 532 Herculina) and significantly more precise estimates for six others (2 Pallas, 3 Juno, 4 Vesta, 9 Metis, 16 Psyche, and 88 Thisbe). However, we also find that the conventional algorithm yields questionable results in several gravitationally coupled cases. To address such cases, we describe a new algorithm that allows the epoch state vectors of the subject asteroids to be included as solve-for parameters, allowing for the simultaneous solution of the masses and epoch state vectors of multiple subject and test asteroids. We then apply this algorithm to the same 30 main-belt asteroids and conclude that mass determinations resulting from current and future high-precision astrometric sources (such as Gaia ) should conduct a thorough search for possible gravitational couplings and account for their effects.

  8. Simultaneous Determination of Glass Transition Temperatures of Several Polymers.

    Science.gov (United States)

    He, Jiang; Liu, Wei; Huang, Yao-Xiong

    2016-01-01

    A simple and easy optical method is proposed for the determination of glass transition temperature (Tg) of polymers. Tg was determined using the technique of microsphere imaging to monitor the variation of the refractive index of polymer microsphere as a function of temperature. It was demonstrated that the method can eliminate most thermal lag and has sensitivity about six fold higher than the conventional method in Tg determination. So the determined Tg is more accurate and varies less with cooling/heating rate than that obtained by conventional methods. The most attractive character of the method is that it can simultaneously determine the Tg of several polymers in a single experiment, so it can greatly save experimental time and heating energy. The method is not only applicable for polymer microspheres, but also for the materials with arbitrary shapes. Therefore, it is expected to be broadly applied to different fundamental researches and practical applications of polymers.

  9. A novel, sensitive and selective method of UPLC/MS-MS for rapid simultaneous determination of midodrine and its active metabolite desglymidodrine in human plasma: Application to support bioequivalence study in healthy human volunteers.

    Science.gov (United States)

    Patel, Daxesh P; Nair, Sneha; Suhagia, Bhanubhai N; Patel, Bhargav M

    2016-11-30

    A specific, rapid, sensitive and selective ultra-performance liquid chromatography - tandem mass spectrometry has been developed for the simultaneous determination of midodrine and desglymidodrine in human plasma. The analytes and its deuterated analogs were quantitatively extracted from 100μL of human plasma by solid phase extraction technique. Separation of analytes was achieved on the Waters Acquity UPLC BEH C18 (50×2.1mm, 1.7μm) column using acetonitrile-4.0mM ammonium formate, pH 2.5(90:10, v/v) as mobile phase. The protonated analytes were quantified by selected reaction monitoring in the positive ionization mode by triple quadrupole mass spectrometer. The calibration plots were linear over the concentration range of 0.050-50.0ng/mL. The intra-batch and inter-batch precision (%CV) across quality control levels was midodrine tablet in 12 healthy subjects. Reproducibility of assay was proved by reanalysis of 48 incurred samples. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. Development of a rapid and sensitive method for the simultaneous determination of 1,2-dibromoethane, 1,4-dichlorobenzene and naphthalene residues in honey using HS-SPME coupled with GC-MS.

    Science.gov (United States)

    Tsimeli, K; Triantis, T M; Dimotikali, D; Hiskia, A

    2008-06-09

    A new method for the simultaneous determination of 1,4-dichlorobenzene (p-DCB), naphthalene and 1,2-dibromoethane (1,2-DBE) residues in honey has been developed. Analysis is carried out using gas chromatography-mass spectrometry (GC/MS) in selected ion monitoring mode (SIM), after extraction and preconcentration of target analytes by headspace solid-phase microextraction (HS-SPME), with a 100 microm film thickness polydimethylsiloxane (PDMS) fiber. Several parameters affecting the extension of the adsorption process (i.e., addition of salt, extraction time, extraction temperature) were studied. The optimal conditions for the determination of these analytes were established. The proposed HS-SPME method showed good sensitivity, without carryover between the samples. Linearity was studied from 5 to 2500 microg kg(-1) for p-DCB, 0.5 to 500 microg kg(-1) for naphthalene and 5 to 500 microg kg(-1) honey for 1,2-DBE with correlation coefficients (r(2)) ranging from 0.9901 to 0.9999. Precision was assessed and both intra and inter-day R.S.D.s (%) were below 6.3%. The detection limits were found to be 1, 0.1 and 2 microg kg(-1) honey for p-DCB, naphthalene and 1,2-DBE, respectively. The percentage recoveries that were evaluated with the proposed HS-SPME method and the standard addition calibration technique gave values among 72.8 and 104.3% for measurements in samples spiked with one target analyte or mixtures of the three. This method has been applied for the analysis of unknown honey samples. The results showed an excellent applicability of the proposed method for the determination of the target compounds in honey samples.

  11. Spectrophotometric simultaneous determination of uranium and thorium using partial least squares regression and orthogonal signal correction

    OpenAIRE

    Niazi, Ali

    2006-01-01

    A simple, novel and sensitive spectrophotometric method was described for simultaneous determination of uranium and thorium. The method is based on the complex formation of uranium and thorium with Arsenazo III at pH 3.0. All factors affecting the sensitivity were optimized and the linear dynamic range for determination of uranium and thorium found. The simultaneous determination of uranium and thorium mixtures by using spectrophotometric methods is a difficult problem, due to spectral interf...

  12. Simultaneous spectrophotometric determination of tungsten and molybdenum with dithiol

    International Nuclear Information System (INIS)

    Navale, A.S.

    1987-01-01

    Toluene-3,4-dithiol is a very sensitive reagent for the spectrophotometric determination of tungsten and molybdenum. Since the absorption spectra of the dithiol complexes of these two elements overlap, a separation of the two elements is carried out. This leads to time consuming extraction procedures. Measuring the absorption of the mixed complexes at two wavelengths and solving a set of simultaneous equations is also not favorable because a lot of time and effort is required for solving the simultaneous equations for each sample. A faster and simpler method is described here for the simultaneous determination of the two elements. The method is based on measurement of absorbance of the mixed complexes at three pre-selected wavelengths and simple calculations involving the absorbance differences. The criteria for selecting the three wavelengths and the theory are described. Application of the method for the determination of tungsten and molybdenum in ore samples is presented. The method is applicable to any similar system consisting of two interfering components. 4 figures, 2 tables, 6 refs. (author)

  13. Simultaneous Determination of Mutagenicity and Toxicity of ...

    African Journals Online (AJOL)

    A demonstration of cytotoxicity is required (measurement of cell number, culture confluency and inhibition of mitotic index) for in vitro cytogenetic assays. The study therefore investigated whether delayed cytotoxicity can be used to simultaneously predict mutagenicity and cytotoxicty. Chinese hamster lung cells were ...

  14. Validation of a Rapid and Sensitive UPLC-MS-MS Method Coupled with Protein Precipitation for the Simultaneous Determination of Seven Pyrethroids in 100 µL of Rat Plasma by Using Ammonium Adduct as Precursor Ion.

    Science.gov (United States)

    Singh, Sheelendra Pratap; Dwivedi, Nistha; Raju, Kanumuri Siva Rama; Taneja, Isha; Wahajuddin, Mohammad

    2016-04-01

    United States Environmental Protection Agency has recommended estimating pyrethroids' risk using cumulative exposure. For cumulative risk assessment, it would be useful to have a bioanalytical method for quantification of one or several pyrethroids simultaneously in a small sample volume to support toxicokinetic studies. Therefore, in the present study, a simple, sensitive and high-throughput ultraperformance liquid chromatography-tandem mass spectrometry method was developed and validated for simultaneous analysis of seven pyrethroids (fenvalerate, fenpropathrin, bifenthrin, lambda-cyhalothrin, cyfluthrin, cypermethrin and deltamethrin) in 100 µL of rat plasma. A simple single-step protein precipitation method was used for the extraction of target compounds. The total chromatographic run time of the method was 5 min. The chromatographic system used a Supelco C18 column and isocratic elution with a mobile phase consisting of methanol and 5 mM ammonium formate in the ratio of 90 : 10 (v/v). Mass spectrometer (API 4000) was operated in multiple reaction monitoring positive-ion mode using the electrospray ionization technique. The calibration curves were linear in the range of 7.8-2,000 ng/mL with correlation coefficients of ≥ 0.99. All validation parameters such as precision, accuracy, recovery, matrix effect and stability met the acceptance criteria according to the regulatory guidelines. The method was successfully applied to the toxicokinetic study of cypermethrin in rats. To the best of our knowledge, this is the first LC-MS-MS method for the simultaneous analysis of pyrethroids in rat plasma. This validated method with minimal modification can also be utilized for forensic and clinical toxicological applications due to its simplicity, sensitivity and rapidity. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  15. Validation of a Rapid and Sensitive UPLC–MS-MS Method Coupled with Protein Precipitation for the Simultaneous Determination of Seven Pyrethroids in 100 µL of Rat Plasma by Using Ammonium Adduct as Precursor Ion

    Science.gov (United States)

    Singh, Sheelendra Pratap; Dwivedi, Nistha; Raju, Kanumuri Siva Rama; Taneja, Isha; Wahajuddin, Mohammad

    2016-01-01

    United States Environmental Protection Agency has recommended estimating pyrethroids’ risk using cumulative exposure. For cumulative risk assessment, it would be useful to have a bioanalytical method for quantification of one or several pyrethroids simultaneously in a small sample volume to support toxicokinetic studies. Therefore, in the present study, a simple, sensitive and high-throughput ultraperformance liquid chromatography–tandem mass spectrometry method was developed and validated for simultaneous analysis of seven pyrethroids (fenvalerate, fenpropathrin, bifenthrin, lambda-cyhalothrin, cyfluthrin, cypermethrin and deltamethrin) in 100 µL of rat plasma. A simple single-step protein precipitation method was used for the extraction of target compounds. The total chromatographic run time of the method was 5 min. The chromatographic system used a Supelco C18 column and isocratic elution with a mobile phase consisting of methanol and 5 mM ammonium formate in the ratio of 90 : 10 (v/v). Mass spectrometer (API 4000) was operated in multiple reaction monitoring positive-ion mode using the electrospray ionization technique. The calibration curves were linear in the range of 7.8–2,000 ng/mL with correlation coefficients of ≥0.99. All validation parameters such as precision, accuracy, recovery, matrix effect and stability met the acceptance criteria according to the regulatory guidelines. The method was successfully applied to the toxicokinetic study of cypermethrin in rats. To the best of our knowledge, this is the first LC–MS-MS method for the simultaneous analysis of pyrethroids in rat plasma. This validated method with minimal modification can also be utilized for forensic and clinical toxicological applications due to its simplicity, sensitivity and rapidity. PMID:26801239

  16. Simultaneous determination of isoniazid and pyrazinamide in ...

    African Journals Online (AJOL)

    Abstract. Purpose: To develop and validate a new high performance liquid chromatographic (HPLC) method for ... pyrazinamide (PZA) are the mainstay drugs in ..... High-performance liquid chromatographic determination of isoniazid, acetylisoniazid and hydrazine in biological fluids. J. Chromatogr. B 1995; 674: 269-. 275.

  17. Simultaneous determination of actinides by x-ray fluorescence spectrometry

    International Nuclear Information System (INIS)

    Cohen, V.H.

    1990-01-01

    The x-ray spectrometric simultaneous determination of uranium and plutonium in simulated Purex Process solutions is described. The method is accomplished by intensity measurements of the L α sub(1) lines. The thin film technique for sample preparation and thorium as an internal standard had been used. An evaporation technique had been also tested for low concentration uranium solutions. In the measurement range 0,05 - 130 U g/L, 0,5 - 20 Pu g/L linear calibration curves were effected. The standard deviation in the concentration range 10 to 130 g/L was 3,5%, 4% in the 1 to 10 g/L and 13% in 0,05 to 1 g/L for uranium determination and 4% for plutonium determination in the range of 1 to 20 g/L. The sensitivity of the method was about 3,62 μg to U and 3,95 μg to Pu. Uranium and plutonium do not reciprocally interfere with one another until U/Pu ≅ 90 m/m. The fission product as interfering elements were also verified. Finally, uranium and plutonium were determined in simulated Purex Process solutions within the requested accuracy for control method. (author)

  18. Simultaneous Determination of Two Isomers of Asarone in Piper ...

    African Journals Online (AJOL)

    Simultaneous Determination of Two Isomers of Asarone in Piper sarmentosum Roxburgh (Piperaceae) Extracts using Different Chromatographic Columns. Mohd Shahrul Ridzuan Hamil, Abdul Hakeem Memon, Amin Malik Shah Abdul Majid, Zhari Ismail ...

  19. SIMULTANEOUS SPECTROPHOTOMETRIC DETERMINATION OF MONTELUKAST SODIUM AND BAMBUTEROL HYDROCHLORIDE IN TABLETS

    OpenAIRE

    Patel Satish A; Patel Dhara J; Patel Natavarlal J.

    2011-01-01

    The present manuscript describe simple, sensitive, rapid, accurate, precise and economical first derivative spectrophotometric method for the simultaneous determination of montelukast sodium and bambuterol hydrochloride in combined tablet dosage form. The derivative spectrophotometric method was based on the determination of both the drugs at their respective zero crossing point (ZCP). The first order derivative spectra was obtained in chloroform and the determinations were made at 241 nm (ZC...

  20. Simultaneous Determination of Bisphenol A and Bisphenol S in ...

    African Journals Online (AJOL)

    NICO

    2014-08-08

    Aug 8, 2014 ... A simplified method based on ratio derivative ultraviolet spectrometry for simultaneous determination of bisphenol A (BPA) and bisphenol S (BPS) in environmental water is presented. The method provides a direct analysis of the samples without tedious sample preparation. In this method, the overlapping ...

  1. Simultaneous Determination of Flavonols and Terpene Lactones in ...

    African Journals Online (AJOL)

    Purpose: To develop an ultra-performance liquid chromatography-tandem mass spectrometry (UPLCMS/MS) method for the simultaneous determination of 7 major components of Ginkgo leaf (kaempferol, quercetin, isorhamnetin, ginkgolides A, ginkgolides B, ginkgolides C and bilobalide) in dog plasma. Methods: Beagle ...

  2. Simultaneous Determination of Metals in Coal with Low-Resolution ...

    African Journals Online (AJOL)

    The setup including low-resolution spectrometer with the charge-coupled device (CCD) detector, continuum radiation source and filter furnace (FF) atomizer was employed for direct simultaneous determination of Al, Fe, Mg, Cu and Mn in coal slurry. In the FF, sample vapour entered absorption volume by filtering through ...

  3. Simultaneous Determination of Bisphenol A and Bisphenol S in ...

    African Journals Online (AJOL)

    NICO

    2014-08-08

    Aug 8, 2014 ... Simultaneous Determination of Bisphenol A and. Bisphenol S in Environmental Water using Ratio Derivative. Ultraviolet Spectrometry. Guiping Cao*, Yafeng Zhuang and Baoliang Liu. Department of Chemical Engineering, Changzhou Institute of Technology, Changzhou, 213022, P.R. China. Received 18 ...

  4. Radioenzymatic simultaneous determination of epinephrine and norepinephrine in plasma

    International Nuclear Information System (INIS)

    Mueller, T.

    1978-01-01

    The high-pressure liquid chromatography (= HPLC) was used in simultaneous determinations of a few pg epinephrine and norepinephrine. This separation procedure improves the efficiency when compared with the conventional thin-layer chromatographic methods (TLC) and allows routine assays in plasma. (orig.) [de

  5. Simultaneous determination of warehouse layout and control policies

    NARCIS (Netherlands)

    Roodbergen, Kees Jan; Vis, Iris F. A.; Taylor, G. Don

    2015-01-01

    In a supply chain's order fulfilment process, it is often the warehouse that plays a central role in making the right product available to the right customer at the right time. This paper aims to improve warehouse performance by deriving an effective design method for the simultaneous determination

  6. Determination of phenols using simultaneous steam distillation-extraction.

    Science.gov (United States)

    Barták, P; Frnková, P; Cáp, L

    2000-01-21

    Simultaneous distillation-extraction was proposed as a preconcentration step for the determination of phenol and its derivatives in aqueous and soil samples. Detection limits of 0.01 mg l(-1) (water) and 0.1 mg kg(-1) (soil) were achieved by gas chromatography-flame ionization detection. The described preconcentration procedure was applied for the primary study of the adsorption equilibrium in a water-soil system serving as a model of phenol behaviors in the environment.

  7. Simultaneous Determination of Co-formulated Matrine and ...

    African Journals Online (AJOL)

    Purpose: To develop and validate a new, simple, sensitive and accurate high performance liquid chromatographic (HPLC) method for the simulataneous determination of matrine and secnidazole in suppositories. Methods: The method involved using a SinoChoom ODS-BP C18 column (5 ƒÊm, 4.6 mm ~ 200 mm) and ...

  8. Simultaneous determination of inorganic and organic anions by ion chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Park, Yang Soon; Joe, Ki Soo; Han, Sun Ho; Park, Soon Dal; Choi, Kwang Soon

    1999-06-01

    Four methods were investigated for the simultaneous determination of several inorganic and organic anions in aqueous solution by ion chromatography. The first is two columns coupled system. The second is the gradient elution system with an anion exchange column. The third is the system with a mixed-mode stationary phase. The fourth is the system with an anion exchange column and the eluant of low conductivity without ion suppressor. The advantages and disadvantages of individual systems were discussed. The suitable methods were proposed for the application to the samples of the nuclear power industry and the environment. (author)

  9. Method for the simultaneous determination of nitrogen, phosphorus and potassium

    International Nuclear Information System (INIS)

    Srapeniants, R.A.; Saveliev, I.B.; Kovtun, J.L.; Sidorov, A.V.; Tsagolov, K.S.

    1980-01-01

    A method for the simultaneous determination of the nitrogen, phosphorus and potassium contents of materials containing them, such as vegetable materials and fertilisers, comprises exposing samples to be analysed and standard samples to neutron irradiation, recording the spectra of gamma radiation induced in the samples, laying the samples aside for a period of time determined by the half-life of the gamma ray-emitting isotopes, again recording the spectra of the samples being analysed and those of the standard samples, superimposing the first and second spectra of the samples being analysed and standard samples and shifting them relative to each other along the energy axis, and determining the content of the elements being analysed by comparing the spectra of the samples being analysed with those of the standard samples. (author)

  10. Simultaneous determination of aluminium and phosphorus by neutron activation analysis

    International Nuclear Information System (INIS)

    Gatschke, W.; Gawlik, D.

    1980-01-01

    With the use of the pneumatic tube system of the BER II reactor, the irradiation position of which is equipped with a movable cadmium shield, the aluminium and phosphorus levels in bone powder and in human bone biopsies were determined. The contribution of aluminium and phosphorus to the 28 Al activity could be separated mathematically after the samples had been irradiated with and without cadmium shielding. The sensitivity and limit of quantitative determination of the analytical procedure were determined using the addition method and the fact that the levels of each element measured was independent of the amount of the other element was proved. (author)

  11. Spectrophotometric simultaneous determination of uranium and thorium using partial least squares regression and orthogonal signal correction

    Energy Technology Data Exchange (ETDEWEB)

    Niazi, Ali [Azad University of Arak (Iran, Islamic Republic of). Faculty of Sciences. Dept. of Chemistry]. E-mail: ali.niazi@gmail.com

    2006-09-15

    A simple, novel and sensitive spectrophotometric method was described for simultaneous determination of uranium and thorium. The method is based on the complex formation of uranium and thorium with Arsenazo III at pH 3.0. All factors affecting the sensitivity were optimized and the linear dynamic range for determination of uranium and thorium found. The simultaneous determination of uranium and thorium mixtures by using spectrophotometric methods is a difficult problem, due to spectral interferences. By multivariate calibration methods such as partial least squares (PLS), it is possible to obtain a model adjusted to the concentration values of the mixtures used in the calibration range. Orthogonal signal correction (OSC) is a preprocessing technique used for removing the information unrelated to the target variables based on constrained principal component analysis. OSC is a suitable preprocessing method for PLS calibration of mixtures without loss of prediction capacity using spectrophotometric method. In this study, the calibration model is based on absorption spectra in the 600-760 nm range for 25 different mixtures of uranium and thorium. Calibration matrices contained 0.10- 21.00 and 0.25-18.50 {mu}g mL{sup -1} of uranium and thorium, respectively. The RMSEP for uranium and thorium with OSC and without OSC were 0.4362, 0.4183 and 1.5710, 1.0775, respectively. This procedure allows the simultaneous determination of uranium and thorium in synthetic and real matrix samples with good reliability of the determination. (author)

  12. A high sensitive biosensor based on FePt/CNTs nanocomposite/N-(4-hydroxyphenyl)-3,5-dinitrobenzamide modified carbon paste electrode for simultaneous determination of glutathione and piroxicam.

    Science.gov (United States)

    Karimi-Maleh, Hassan; Tahernejad-Javazmi, Fahimeh; Ensafi, Ali A; Moradi, Reza; Mallakpour, Shadpour; Beitollahi, Hadi

    2014-10-15

    This study describes the development, electrochemical characterization and utilization of novel modified N-(4-hydroxyphenyl)-3,5-dinitrobenzamide-FePt/CNTs carbon paste electrode for the electrocatalytic determination of glutathione (GSH) in the presence of piroxicam (PXM) for the first time. The synthesized nanocomposite was characterized with different methods such as TEM and XRD. The modified electrode exhibited a potent and persistent electron mediating behavior followed by well-separated oxidation peaks of GSH and PXM. The peak currents were linearly dependent on GSH and PXM concentrations in the range of 0.004-340 and 0.5-550 µmol L(-1), with detection limits of 1.0 nmol L(-1) and 0.1 µmolL(-1), respectively. The modified electrode was successfully used for the determination of the analytes in real samples with satisfactory results. Copyright © 2014 Elsevier B.V. All rights reserved.

  13. Spectrophotometric Methods for Simultaneous Determination of Oxytetracycline HCl and Flunixin Meglumine in Their Veterinary Pharmaceutical Formulation

    OpenAIRE

    Merey, Hanan A.; Abd-Elmonem, Mahmmoud S.; Nazlawy, Hagar N.; Zaazaa, Hala E.

    2017-01-01

    Four precise, accurate, selective, and sensitive UV-spectrophotometric methods were developed and validated for the simultaneous determination of a binary mixture of Oxytetracycline HCl (OXY) and Flunixin Meglumine (FLU). The first method, dual wavelength (DW), depends on measuring the difference in absorbance (ΔA 273.4–327 nm) for the determination of OXY where FLU is zero while FLU is determined at ΔA 251.7–275.7 nm. The second method, first-derivative spectrophotometric method (1D), depend...

  14. Environmental Method to Determine Dopamine and Ascorbic Acid Simultaneously via Derivative Spectrophotometry

    Directory of Open Access Journals (Sweden)

    Ahmed M. El-Zohry

    2013-01-01

    Full Text Available Many various methods were applied to determine dopamine and ascorbic acid simultaneously using hazardous materials and complex procedures. Derivative absorption spectra can give safely and five sensitive derivative equations that are used for the simultaneous determination of dopamine and ascorbic acid in the UV region, using first and second derivative spectroscopy with high precision at pH value of 9.2. Dopamine and ascorbic acid can be detected in the ranges of 0.375–9.45 mg L−1 and 0.352–5.28 mg L−1, respectively. These obtained methods could be used to determine both reagents in real and synthesized samples.

  15. Preconcentration NAA for simultaneous multielemental determination in water sample

    International Nuclear Information System (INIS)

    Chatt, A.

    1999-01-01

    Full text: Environment concerns with water, air, land and their interrelationship viz., human beings, fauna and flora. One of the important environmental compartments is water. Elements present in water might face a whole lot of physico-chemical conditions. This poses challenges to measure their total concentrations as well as different species. Preconcentration of the elements present in water samples is a necessary requisites in water analysis. For multi elements concentration measurements, Neutron Activation Analysis (NAA) is one of the preferred analytical techniques due to its sensitivity and selectivity. In this talk preconcentration NAA for multielemental determination in water sample determination will be discussed

  16. Simultaneous determination of U and Pu isotopes by alpha spectrometry

    International Nuclear Information System (INIS)

    Equillor, H.E.; Campos, J.M.

    2011-01-01

    Determination of actinides by alpha spectrometry is usually carried out after full separation of each of the components of the sample. The procedure presented in this paper permits U and Pu isotopes to be measured together allowing faster sample processing and measurement. The method consists in the extraction with tributyl phosphate of U and Pu isotopes from the rest of the matrix, followed by a cathodic electrodeposition to obtain alpha spectrometry suitable pieces. It can be applied to various environmental samples, such as water, filters and soil (about 0.5 g of solid sample for the described conditions). High-quality electroplated discs are essential for simultaneous processing, so a technique to achieve this requirement is also explained. (authors) [es

  17. Efficient Noninferiority Testing Procedures for Simultaneously Assessing Sensitivity and Specificity of Two Diagnostic Tests

    Directory of Open Access Journals (Sweden)

    Guogen Shan

    2015-01-01

    Full Text Available Sensitivity and specificity are often used to assess the performance of a diagnostic test with binary outcomes. Wald-type test statistics have been proposed for testing sensitivity and specificity individually. In the presence of a gold standard, simultaneous comparison between two diagnostic tests for noninferiority of sensitivity and specificity based on an asymptotic approach has been studied by Chen et al. (2003. However, the asymptotic approach may suffer from unsatisfactory type I error control as observed from many studies, especially in small to medium sample settings. In this paper, we compare three unconditional approaches for simultaneously testing sensitivity and specificity. They are approaches based on estimation, maximization, and a combination of estimation and maximization. Although the estimation approach does not guarantee type I error, it has satisfactory performance with regard to type I error control. The other two unconditional approaches are exact. The approach based on estimation and maximization is generally more powerful than the approach based on maximization.

  18. Simultaneous determination of glycols based on fluorescence anisotropy

    International Nuclear Information System (INIS)

    Garcia Sanchez, F.; Navas Diaz, A.; Lopez Guerrero, M.M.

    2007-01-01

    Simultaneous determination of non-fluorescent glycols in mixtures without separation or chemical transformation steps is described. Two methods based in the measure of fluorescence anisotropy of a probe such as fluorescein dissolved in the analyte or analyte mixtures are described. In the first method, the anisotropy spectra of pure and mixtures of analytes are used to quantitative determination (if the fluorophor concentration is in a range where fluorescence intensity is proportional to concentration). In the second method, a calibration curve anisotropy-concentration based on the application of the Perrin equation is established. The methods presented here are capable of directly resolving binary mixtures of non-fluorescent glycols on the basis of differences on the fluorescence anisotropy of a fluorescence tracer. Best analytical performances were obtained by application of the method based on Perrin equation. This method is simple, rapid and allows the determination of mixtures of glycols with reasonable accuracy and precision. Detection limits are limited by the quantum yield and anisotropy values of the tracer in the solvents. Recovery values are related to the differences in anisotropy values of the tracer in the pure solvents. Mixtures of glycerine/ethylene glycol (GL/EG), ethylene glycol/1,2-propane diol (EG/1,2-PPD) and polyethylene glycol 400/1,2-propane diol (PEG 400/1,2-PPD) were analysed and recovery values are within 95-120% in the Perrin method. Relative standard deviation are in the range 1.3-2.9% and detection limits in the range 3.9-8.9%

  19. Simultaneous first order derivative spectrophotometric determination of vanadium and zirconium in alloy steels and minerals.

    Science.gov (United States)

    Varghese, Anitha; George, Louis

    2012-09-01

    A simple, selective and sensitive spectrophotometric method has been developed for the individual and simultaneous determination of trace amounts of vanadium(V) and zirconium(IV) in acetic acid medium using a newly synthesised reagent diacetylmonoxime salicyloylhydrazone (DMSH), without any prior separation. The molar absorptivity and Sandell's sensitivity of the coloured species are 1.30 x 10(4) and 1.82 x 10(4) L mol(-1)cm(-1) and 3.9 and 2.5 ng cm(-2) for V(V) and Zr(IV), respectively. Beer's law is obeyed between 0.26-2.80 and 0.30-3.20 μg mL(-1) concentration of vanadium (V) and zirconium (IV) at 405 and 380 nm respectively. The stoichiometry of the complex was found to be 1:1 (metal:ligand) for V(V) and 1:2 for Zr(IV) complexes. These metal ions interfere with the determination of each other in zero order spectrophotometry. The first derivative spectra of these complexes permitted a simultaneous determination of V(V) and Zr(IV) at zero crossing wavelengths of 445 nm and 405 nm, respectively. The optimum conditions for maximum colour development and other analytical parameters were evaluated. The proposed method has been successfully applied for the determination of zirconium and vanadium in standard alloy steel samples, mineral and soil samples. Copyright © 2012 Elsevier B.V. All rights reserved.

  20. Stability-indicating HPLC Method for Simultaneous Determination of Aspirin and Prasugrel

    OpenAIRE

    Patel, Shital M.; Patel, C. N.; Patel, V. B.

    2013-01-01

    A simple, sensitive, specific, accurate, and stability-indicating reversed phase high performance liquid chromatographic method was developed for the simultaneous determination of aspirin and prasugrel, using a Kromasil 100 C 18 (150×4.6 mm, 5 μ) column and a mobile phase composed of acetonitrile:methanol:water (30:10:60, v/v), pH 3.0 adjusted with o-phosphoric acid. The retention times of aspirin and prasugrel were found to be 3.28 min and 6.61 min, respectively. Linearity was established fo...

  1. Simultaneous determination of four food allergens using compact disc immunoassaying technology.

    Science.gov (United States)

    Badran, Ahmed Ali; Morais, Sergi; Maquieira, Ángel

    2017-03-01

    A multiplex competitive microimmunoassay for the simultaneous determination of gliadin, casein, β-lactoglobulin, and ovalbumin is presented. The assay in microarray format is performed on a DVD where the allergens are physisorbed on the polycarbonate surface of the disc. The immunointeraction is detected using a mixture of specific gold-labeled antibodies and the signal amplified with the silver enhancement method. The optical density of the precipitate, read by a DVD drive, is related to the concentration of the four allergens in sample. An optimized protocol for the simultaneous extraction of the allergen proteins from food samples is also addressed. The suitability of the method is demonstrated for the simultaneous quantitative extraction and determination of the targeted allergens in spiked baby foods, juices, and beers. The sensitivity (EC50) of the multiplexed assay was 0.04, 0.40, 0.08, and 0.16 mg L -1 for gliadin, casein, β-lactoglobulin, and ovalbumin, respectively, and the recovery results from the analysis of food samples ranged from 72 to 117%. A portable, easy-to-use, array-based bioanalytical method is developed for quantification of food allergens with a limit of detection below the accepted levels of the international legislations, which allows promotion of food safety and quality. Graphical abstract GLI Gliadin, CAS Casein, β-LAC β-lactoglobulin, OVA Ovalbumin.

  2. Validation of simultaneous volumetric and spectrophotometric methods for the determination of captopril in pharmaceutical formulations.

    Science.gov (United States)

    Rahman, Nafisur; Singh, Manisha; Hoda, Nasrul

    2005-01-01

    Simple, sensitive and economical simultaneous volumetric and spectrophotometric methods for the determination of captopril have been developed. The methods were based on the reaction of captopril with potassium iodate in HCl medium. Amaranth was used as indicator to detect the end-point of the titration in aqueous layer. The iodine formed during the titration was extracted into CCl4 and subsequently determined spectrophotometrically at 510 nm. The Beer's law was obeyed in the concentration range of 120-520 microg ml-1. Rigorous statistical analyses were performed for the validation of the proposed methods. The proposed methods were successfully applied to the determination of captopril in dosage forms. Comparison of the means of the proposed procedures with those of reference methods using point and interval hypothesis tests showed no statistically significant difference.

  3. Simultaneous Determination of Flavonols and Terpene Lactones in ...

    African Journals Online (AJOL)

    (UPLC-TMS). Then the pharmacokinetics of these target compounds, of different preparations were studied. Results: The adjusted pharmacokinetic data showed that the ... Conclusion: The results indicate that UPLC-TMS can used to simultaneously evaluate the plasma .... T1/2, were calculated with the software program.

  4. Rapid and sensitive approach to simultaneous detection of genomes of hepatitis A, B, C, D and E viruses.

    Science.gov (United States)

    Kodani, Maja; Mixson-Hayden, Tonya; Drobeniuc, Jan; Kamili, Saleem

    2014-10-01

    Five viruses have been etiologically associated with viral hepatitis. Nucleic acid testing (NAT) remains the gold standard for diagnosis of viremic stages of infection. NAT methodologies have been developed for all hepatitis viruses; however, a NAT-based assay that can simultaneously detect all five viruses is not available. We designed TaqMan card-based assays for detection of HAV RNA, HBV DNA, HCV RNA, HDV RNA and HEV RNA. The performances of individual assays were evaluated on TaqMan Array Cards (TAC) for detecting five viral genomes simultaneously. Sensitivity and specificity were determined by testing 329 NAT-tested clinical specimens. All NAT-positive samples for HCV (n = 32), HDV (n = 28) and HEV (n = 14) were also found positive in TAC (sensitivity, 100%). Forty-three of 46 HAV-NAT positive samples were also positive in TAC (sensitivity, 94%), while 36 of 39 HBV-NAT positive samples were positive (sensitivity, 92%). No false-positives were detected for HBV (n = 32), HCV (n = 36), HDV (n = 30), and HEV (n = 31) NAT-negative samples (specificity 100%), while 38 of 41 HAV-NAT negative samples were negative by TAC (specificity 93%). TAC assay was concordant with corresponding individual NATs for hepatitis A-E viral genomes and can be used for their detection simultaneously. The TAC assay has potential for use in hepatitis surveillance, for screening of donor specimens and in outbreak situations. Wider availability of TAC-ready assays may allow for customized assays, for improving acute jaundice surveillance and for other purposes for which there is need to identify multiple pathogens rapidly. Published by Elsevier B.V.

  5. [Simultaneous determination of 10 synthetic colorants in cosmetics by high performance liquid chromatography].

    Science.gov (United States)

    Liu, Haishan; Qian, Xiaoyan; Lü, Chunhu; Zhu, Xiaoyu; Chen, Xiaomei; Mo, Weimin

    2013-11-01

    A high performance liquid chromatographic method was developed for the simultaneous determination of 10 synthetic colorants in cosmetics. The cosmetics were extracted by the ultrasonic technique with tetrahydrofuran (THF), dimethyl sulfoxide (DMSO) and methanol sequentially. Then the extracts were centrifuged for purification and separated on an Eclipse XDB-C18 column (150 mm x 4.6 mm, 5 microm) with gradient elution by acetonitrile and 0.02 mol/L ammonium acetate (pH 4.60, adjusted with acetic acid). A diode array detector was used to determine the colorants with the wavelengths ranging from 417 nm to 640 nm. The linear relationships of the 10 colorants between the peak areas and the mass concentrations were obtained in the range of 0.5-20.0 mg/L (r > 0.999). The limits of quantitation ranged from 10 to 20 mg/kg. The average recoveries at three concentration levels ranged from 92.9% to 108.8% with the relative standard deviations in the range of 0.5% to 6.1% (n = 6). The method is simple, rapid and sensitive. It is suitable for the simultaneous determination of the 10 colorants in the oil cosmetics, cream cosmetics and powder cosmetics.

  6. Simultaneous determination of paracetamol and penicillin V by square-wave voltammetry at a bare boron-doped diamond electrode

    International Nuclear Information System (INIS)

    Švorc, Ľubomír; Sochr, Jozef; Tomčík, Peter; Rievaj, Miroslav; Bustin, Dušan

    2012-01-01

    Highlights: ► Unmodified BDD electrode = sensitive electrochemical sensor for drugs determination. ► No special pretreatment of samples except simple dilution. ► Selective method, common compounds present in urine do not interfere in high excess. ► Simultaneous determination of PAR and PEN has yet not been published in literature. - Abstract: A simple, sensitive and selective square-wave voltammetry method for simultaneous determination of paracetamol and penicillin V on a bare (unmodified) boron-doped diamond electrode has been developed. The good potential separation of about 0.35 V between the oxidation peak potentials of both drugs present in mixture was found. It was found by cyclic voltammetry that paracetamol gave quasireversible wave and penicillin V provided irreversible oxidation peak. The effect of supporting electrolyte, pH and scan rate on voltammetric response of both drugs was studied to select the optimum experimental conditions. The optimal conditions for quantitative simultaneous determination were obtained in acetate buffer solution at pH 5.0. The oxidation peak of paracetamol and penicillin V showed a systematic increase in peak currents with increase of their concentration. The calibration curves for the simultaneous determination of paracetamol and penicillin V exhibited the good linear responses within the concentration range from 0.4 to 100 μM for both drugs. The detection limit was established to 0.21 and 0.32 μM for paracetamol and penicillin V, respectively. The method proved the good sensitivity, repeatability (RSD of 1.5 and 2.1% for mixture solution of 10 μM PCM and PEN) and selectivity when influence of interferents commonly existing in human urine was negligible. The practical analytical utility of proposed method was demonstrated by simultaneous determination of paracetamol and penicillin V in human urine samples, with results similar to those obtained using a high-performance liquid chromatography method as an

  7. [Simultaneous determination of seven residual solvents in bovis calculus artifactus by headspace gas chromatography].

    Science.gov (United States)

    Chi, Shuyao; Wu, Dike; Sun, Jinhong; Ye, Ruhan; Wang, Xiaoyan

    2014-05-01

    A headspace gas chromatography (HS-GC) method was developed for the simultaneous determination of seven residual solvents (petroleum ether (60-90 degrees C), acetone, ethyl acetate, methanol, methylene chloride, ethanol and butyl acetate) in bovis calculus artifactus. The DB-WAX capillary column and flame ionization detector (FID) were used for the separation and detection of the residual solvents, and the internal standard method was used for the quantification. The chromatographic conditions, such as equilibrium temperature and equilibrium time, were optimized. Under the optimized conditions, all of the seven residual solvents showed good linear relationships with good correlation coefficients (not less than 0.999 3) in the prescribed concentration range. At three spiked levels, the recoveries for the seven residual solvents were 94.7%-105.2% with the relative standard deviations (RSDs) less than 3.5%. The limits of detection (LODs) of the method were 0.43-5.23 mg/L, and the limits of quantification (LOQs) were 1.25-16.67 mg/L. The method is simple, rapid, sensitive and accurate, and is suitable for the simultaneous determination of the seven residual solvents in bovis calculus artifactus.

  8. Simultaneous bulk density and soil moisture determination by attenuation of 137 Cs and 241 Am

    International Nuclear Information System (INIS)

    Barros Ferraz, E.S. de.

    1974-01-01

    The method of simultaneous bulk density and soil moisture determination by attenuation of 241 Am and 137 Cs gamma-radiation is introduced and studied with detail. Theoretical considerations are made about the attenuation process in the absorbers, the form of solving the problem of two unknowns, the sensitivity of the method the influences of the resolution time of the electronic counting equipment, and of the Compton scattering in the sample. From the methodological point of view studies are made about the influence of the geometry, adjustment of counting system, choice of radiation sources, attenuation coefficient and the manner of obtaining reliable measurements. Data obtained are analysed, discussed and compared with those found in the literature. Finally the author presents some applications of the method, its use in soil-water movement studies, in soil profile compaction studies, and specially in swelling soils. (author)

  9. Dual-mode gradient HPLC procedure for the simultaneous determination of chloroquine and proguanil.

    Science.gov (United States)

    Paci, A; Caire-Maurisier, A-M; Rieutord, A; Brion, F; Clair, P

    2002-01-01

    In order to assay the antipaludic capsule of the Service de Santé des Armées (SSA), that contains two antimalarial drugs, i.e. chloroquine sulfate (CQS, cp1) and proguanil hydrochloride (PGH, cp5), a HPLC procedure was developed. A reversed-phase ion-pair high-performance liquid chromatography (HPLC) method with an ultraviolet detection at 254 nm was set up and validated. Elution system includes programming of both organic concentration and flow-rate known as 'dual-mode gradient'. This method allows the simultaneous determination of both active compounds and separation of four process related substances. The method is simple, rapid, selective and accurate, and the precision is good with an inter- and intra-assay of <2%. The sensitivity is particularly suitable for pharmaceutical quality control.

  10. Simultaneous determination of a binary mixture of pantoprazole sodium and itopride hydrochloride by four spectrophotometric methods

    Science.gov (United States)

    Ramadan, Nesrin K.; El-Ragehy, Nariman A.; Ragab, Mona T.; El-Zeany, Badr A.

    2015-02-01

    Four simple, sensitive, accurate and precise spectrophotometric methods were developed for the simultaneous determination of a binary mixture containing Pantoprazole Sodium Sesquihydrate (PAN) and Itopride Hydrochloride (ITH). Method (A) is the derivative ratio method (1DD), method (B) is the mean centering of ratio spectra method (MCR), method (C) is the ratio difference method (RD) and method (D) is the isoabsorptive point coupled with third derivative method (3D). Linear correlation was obtained in range 8-44 μg/mL for PAN by the four proposed methods, 8-40 μg/mL for ITH by methods A, B and C and 10-40 μg/mL for ITH by method D. The suggested methods were validated according to ICH guidelines. The obtained results were statistically compared with those obtained by the official and a reported method for PAN and ITH, respectively, showing no significant difference with respect to accuracy and precision.

  11. Simultaneous determination of plasma total homocysteine and methionine by liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Jiang, Yi; Mistretta, Brandon; Elsea, Sarah; Sun, Qin

    2017-01-01

    The sulfur-containing amino acid homocysteine is a cardiac risk factor and a biomarker for several inborn errors of metabolism in methionine synthesis. A simple LC-MS/MS method was developed and validated for determination of homocysteine and methionine in human plasma. Rapid separation was achieved using a reverse phase liquid chromatography. Mass spectrometry identification was performed in positive electrospray ionization mode for homocysteine and methionine. Accuracy, precision, linearity, recovery and sample stability were evaluated in the method validation. The test is applied in diagnosis of homocystinuria and monitoring total homocysteine levels. Moreover, simultaneous measurement of methionine helps in the differentiation of homocystinuria and some cobalamin disorders (such as cblC and cblD defects) without additional amino acid testing. Lastly, this assay is sensitive to detect reduced total homocysteine levels that are possibly seen in sulfocysteinuria and molybdenum cofactor deficiencies. Copyright © 2016. Published by Elsevier B.V.

  12. [Structure determination of alkyd resins by simultaneous pyrolysis methylation gas chromatography-mass spectometry].

    Science.gov (United States)

    Cao, J Y; Fu, D H; Zhang, F; Liang, D

    2000-09-01

    Several types of alkyd resins have been analyzed by simultaneous pyrolysis methylation gas chromatography mass spectrometry (SPM-GC-MS). The samples were mixed with tetramethylammonium hydroxide, and the process included simultaneous pyrolysis derivatization and mass spectrometry determination. SPM-GC-MS conditions: a vertical microfurnace-type pyrolyzer was directly attached to a gas chromatograph-mass spectrometer. About 20 ug of the mixed alkyd resin sample was introduced into the center of the pyrolyzer at 450 degrees C under the flow of helium carrier gas. The inlet mode was split with an injection interval of 10 s and the inlet pressure was 82.7 kPa. The gas chromatograph was fitted with a fused-silica capillary column ( SE-54 30 m x0.25 mm i.d. x 0.25 um). Temperature program settings were: initial temperature, 40 degrees C, hold 2 min; increase at 6 degrees C min 1 to 220 degrees C, hold 14 min; increase at 10 degrees C min 1 to 280 degrees C, hold 8 min. All pyrolysis products referred to were identified by mass spectrometry. The temperature of the ion source was 210 degrees C and that of the transfer line was 250 degrees C. The technique could give additional information about the composition of the dibasic acids, polyols, six types of drying oils, and modified alkyd resins. The method is sensitive, accurate, convenient, and involves minimal sample manipulation.

  13. Simultaneous Determination of Co-formulated Matrine and ...

    African Journals Online (AJOL)

    HP

    of 6.69 min and linearity for the quantification of the drug was obtained in the concentration range of ... biological samples. To the best of our knowledge, few HPLC methods have been developed in the literature for the determination of matrine and secnidazole in ... Chromatographic analysis was performed using.

  14. A LC-MS/MS method for the specific, sensitive, and simultaneous quantification of 5-aminolevulinic acid and porphobilinogen.

    Science.gov (United States)

    Zhang, Jinglan; Yasuda, Makiko; Desnick, Robert J; Balwani, Manisha; Bishop, David; Yu, Chunli

    2011-08-15

    Accurate determinations of 5-aminolevulinic acid (ALA) and porphobilinogen (PBG) in physiologic fluids are required for the diagnosis and therapeutic monitoring of acute porphyrias. Current colorimetric methods are insensitive and over-estimate ALA and PBG due to poor specificity, while LC-MS/MS methods increase sensitivity, but have limited matrices. An LC-MS/MS method was developed to simultaneously determine ALA and PBG concentrations in fluids or tissues which were solid phase extracted, butanol derivatized, and quantitated by selective reaction monitoring using (13)C(5), (15)N-ALA and 2,4-(13)C(2)-PBG internal standards. ALA was separated from interfering compounds on a reverse phase C8-column. For ALA and PBG, the matrix effects (87.3-105%) and process efficiencies (77.6-97.8% and 37.2-41.6%, respectively) were acceptable in plasma and urine matrices. The assay was highly sensitive for ALA and PBG (LLOQ=0.05 μM with 25 μL urine or 100 μL plasma), and required ∼4 h from extraction to results. ALA and PBG accuracy ranged from 88.2 to 110% (n=10); intra- and inter-assay coefficients of variations were PBG levels when asymptomatic, and high levels during acute attacks, which decreased with hemin therapy. In AIP mice, baseline ALA and PBG levels in urine, plasma, and liver were increased after phenobarbital induction 28-/63-, 42-/266-, and 13-/316-fold, respectively. This LC-MS/MS method is rapid, specific, highly sensitive, accurate, and simultaneously measures ALA and PBG in urine, plasma, and tissues permitting porphyria clinical diagnoses, therapeutic monitoring, and research. Copyright © 2011 Elsevier B.V. All rights reserved.

  15. A LC–MS/MS method for the specific, sensitive, and simultaneous quantification of 5-aminolevulinic acid and porphobilinogen

    Science.gov (United States)

    Zhang, Jinglan; Yasuda, Makiko; Desnick, Robert J.; Balwani, Manisha; Bishop, David; Yu, Chunli

    2012-01-01

    Accurate determinations of 5-aminolevulinic acid (ALA) and porphobilinogen (PBG) in physiologic fluids are required for the diagnosis and therapeutic monitoring of acute porphyrias. Current colorimetric methods are insensitive and over-estimate ALA and PBG due to poor specificity, while LC–MS/MS methods increase sensitivity, but have limited matrices. An LC–MS/MS method was developed to simultaneously determine ALA and PBG concentrations in fluids or tissues which were solid phase extracted, butanol derivatized, and quantitated by selective reaction monitoring using 13C5, 15N-ALA and 2,4-13C2-PBG internal standards. ALA was separated from interfering compounds on a reverse phase C8-column. For ALA and PBG, the matrix effects (87.3–105%) and process efficiencies (77.6–97.8% and 37.2–41.6%, respectively) were acceptable in plasma and urine matrices. The assay was highly sensitive for ALA and PBG (LLOQ = 0.05 µM with 25 µL urine or 100 µL plasma), and required ~4 h from extraction to results. ALA and PBG accuracy ranged from 88.2 to 110% (n = 10); intra- and inter-assay coefficients of variations were PBG levels when asymptomatic, and high levels during acute attacks, which decreased with hemin therapy. In AIP mice, baseline ALA and PBG levels in urine, plasma, and liver were increased after phenobarbital induction 28-/63-, 42-/266-, and 13-/316-fold, respectively. This LC–MS/MS method is rapid, specific, highly sensitive, accurate, and simultaneously measures ALA and PBG in urine, plasma, and tissues permitting porphyria clinical diagnoses, therapeutic monitoring, and research. PMID:21783436

  16. Spectrophotometric methods for simultaneous determination of ternary mixture of amlodipine besylate, olmesartan medoxomil and hydrochlorothiazide

    Science.gov (United States)

    Merey, Hanan A.; Ramadan, Nesrin K.; Diab, Sherine S.; Moustafa, Azza A.

    Four, accurate, precise, and sensitive spectrophotometric methods are developed for the simultaneous determination of a ternary mixture containing amlodipine besylate (AM), olmesartan medoxomil (OL) and hydrochlorothiazide (HZ), where AM is determined at its λmax 364.6 nm (0D), while (OL) and (HZ) are determined by different methods. Method (A) depends on determining OL and HZ by measuring the second derivative of the ratio spectra (2DD) at 254.4 and 338.6 nm, respectively. Method (B) is first derivative of the double divisor ratio spectra (D-1DD) at 260.4 and 273.0 nm for OL and HZ, respectively. Method (C) based on successive spectrophotometric resolution technique (SSRT). The technique starts with the ratio subtraction method then measuring OL and HZ at their isoabsorptive point at 260.0 nm, while HZ is measured using the amplitude of first derivative at 335.2 nm. Method (D) is mean centering of the ratio spectra (MCR) at 252.0 nm and 220.0 nm for OL and HZ, respectively. The specificity of the developed methods is investigated by analyzing laboratory prepared mixtures containing different ratios of the three drugs and their combined dosage form. The obtained results are statistically compared with those obtained by the official or reported methods, showing no significant difference with respect to accuracy and precision at p = 0.05.

  17. Simultaneous Atomic Absorption Spectrometry for Cadmium and Lead Determination in Wastewater: A Laboratory Exercise

    Science.gov (United States)

    Correia, Paulo R. M.; Oliveira, Pedro V.

    2004-01-01

    The simultaneous determination of cadmium and lead by multi-element atomic absorption spectrometry with electrochemical atomization is proposed by employing a problem-based approach. The reports indicate that the students assimilated the principles of the simultaneous atomic absorption spectrometry (SIMAAS), the role of the chemical modifier, the…

  18. Development and evaluation of a liquid chromatography tandem mass spectrometry method for simultaneous determination of salivary melatonin, cortisol and testosterone

    DEFF Research Database (Denmark)

    Jensen, Marie Aarrebo; Hansen, Åse Marie; Abrahamsson, Peter

    2011-01-01

    .1 pmol/L, 0.27 nmol/L and 10.8 pmol/L for melatonin, cortisol, and testosterone, respectively. The developed method was sensitive enough to measure circadian rhythms of all 3 hormones in a pilot study among four healthy volunteers. It can therefor be used to study the impact of night work and working......Circadian disruption can have several possible health consequences, but is not well studied. In order to measure circadian disruption, in relation to shift or night work, we developed a simple and sensitive method for the simultaneous determination of melatonin, cortisol and testosterone in human...

  19. Simulating shelf life determination by two simultaneous criteria.

    Science.gov (United States)

    Peleg, Micha; Normand, Mark D

    2015-12-01

    The shelf life of food and pharmaceutical products is frequently determined by a marker's concentration or quality index falling below or surpassing an assigned threshold level. Naturally, different chosen markers would indicate different shelf life for the same storage temperature history. We demonstrate that if there are two markers, such as two labile vitamins, the order in which their concentrations cross their respective thresholds may depend not only on their degradation kinetic parameters but also on the particular storage temperature profile, be it isothermal or non-isothermal. Thus, at least theoretically, the order observed in accelerated storage need not be always indicative of the actual order at colder temperatures, except where the two degradation reactions follow the same kinetic order and their temperature-dependence rate parameter is also the same. This is shown with simulated hypothetical degradation reactions that follow first or zero order kinetics and whose rate constant's temperature-dependence obeys the exponential model. It is also demonstrated with simulated hypothetical Maillard reaction's products whose synthesis rather than their degradation follows pseudo zero order kinetics. The software developed to do the simulations and calculate the thresholds crossing points has been posted on the Internet as a freely downloadable interactive Wolfram Demonstration, which can be used as a tool in storage studies and shelf life prediction. In principle, the methodology can be extended from two to any number of markers. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. Spectrophotometric Methods for Simultaneous Determination of Oxytetracycline HCl and Flunixin Meglumine in Their Veterinary Pharmaceutical Formulation.

    Science.gov (United States)

    Merey, Hanan A; Abd-Elmonem, Mahmmoud S; Nazlawy, Hagar N; Zaazaa, Hala E

    2017-01-01

    Four precise, accurate, selective, and sensitive UV-spectrophotometric methods were developed and validated for the simultaneous determination of a binary mixture of Oxytetracycline HCl (OXY) and Flunixin Meglumine (FLU). The first method, dual wavelength (DW), depends on measuring the difference in absorbance (ΔA 273.4-327 nm) for the determination of OXY where FLU is zero while FLU is determined at ΔA 251.7-275.7 nm. The second method, first-derivative spectrophotometric method (1D), depends on measuring the peak amplitude of the first derivative selectively at 377 and 266.7 nm for the determination of OXY and FLU, respectively. The third method, ratio difference method, depends on the difference in amplitudes of the ratio spectra at ΔP 286.5-324.8 nm and ΔP 249.6-286.3 nm for the determination of OXY and FLU, respectively. The fourth method, first derivative of ratio spectra method (1DD), depends on measuring the amplitude peak to peak of the first derivative of ratio spectra at 296.7 to 369 nm and 259.1 to 304.7 nm for the determination of OXY and FLU, respectively. Different factors affecting the applied spectrophotometric methods were studied. The proposed methods were validated according to ICH guidelines. Satisfactory results were obtained for determination of both drugs in laboratory prepared mixture and pharmaceutical dosage form. The developed methods are compared favourably with the official ones.

  1. Spectrophotometric Methods for Simultaneous Determination of Oxytetracycline HCl and Flunixin Meglumine in Their Veterinary Pharmaceutical Formulation

    Directory of Open Access Journals (Sweden)

    Hanan A. Merey

    2017-01-01

    Full Text Available Four precise, accurate, selective, and sensitive UV-spectrophotometric methods were developed and validated for the simultaneous determination of a binary mixture of Oxytetracycline HCl (OXY and Flunixin Meglumine (FLU. The first method, dual wavelength (DW, depends on measuring the difference in absorbance (ΔA 273.4–327 nm for the determination of OXY where FLU is zero while FLU is determined at ΔA 251.7–275.7 nm. The second method, first-derivative spectrophotometric method (1D, depends on measuring the peak amplitude of the first derivative selectively at 377 and 266.7 nm for the determination of OXY and FLU, respectively. The third method, ratio difference method, depends on the difference in amplitudes of the ratio spectra at ΔP 286.5–324.8 nm and ΔP 249.6–286.3 nm for the determination of OXY and FLU, respectively. The fourth method, first derivative of ratio spectra method (1DD, depends on measuring the amplitude peak to peak of the first derivative of ratio spectra at 296.7 to 369 nm and 259.1 to 304.7 nm for the determination of OXY and FLU, respectively. Different factors affecting the applied spectrophotometric methods were studied. The proposed methods were validated according to ICH guidelines. Satisfactory results were obtained for determination of both drugs in laboratory prepared mixture and pharmaceutical dosage form. The developed methods are compared favourably with the official ones.

  2. Simultaneous determination of ramipril, ramiprilat and telmisartan in human plasma using liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    Gupta, V K; Jain, Rajeev; Lukram, Ojitkumar; Agarwal, Shilpi; Dwivedi, Ashish

    2011-01-15

    A rapid and sensitive liquid chromatography tandem mass spectrometry method has been developed and validated for the simultaneous determination of ramipril, ramiprilat and telmisartan in human plasma. The solid-phase extraction technique was used for the extraction of ramipril, ramiprilat and telmisartan from human plasma. Trandolaprilat and hydrochlorothiazide were used as the internal standards (ISs). Chromatography was performed on a Hypurity C18, 5 μm, 50 mm × 4.6mm column, with the mobile phase consisting of ammonium acetate and acetonitrile (in a 20:80 ratio), followed by detection using mass spectrometry. The method involves a simple reversed isocratic chromatography condition and mass spectrometry detection, which enables detection at sub-nanogram levels. The method was validated and the lower limit of quantification for ramipril, ramiprilat and telmisartan was found to be 0.1 ng mL(-1), 0.1 ng mL(-1) and 2 ng mL(-1), respectively. The mean recovery for ramipril, ramiprilat and telmisartan ranged from 90.1 to 104.1%. This method increased the sensitivity and selectivity; resulting in high-throughput analysis of ramipril, ramiprilat and telmisartan using two different ISs in a single experiment for bioequivalence studies, with a chromatographic run time of 1.5 min only. Copyright © 2010 Elsevier B.V. All rights reserved.

  3. [Simultaneous determination of gestodene, etonogestrel and ethinylestradiol in plasma by LC-MS/MS following derivatization].

    Science.gov (United States)

    Liu, Xiao-Fen; Ding, Cun-Gang; Ge, Qing-Hua; Zhou, Zhen; Zhi, Xiao-Jin

    2010-01-01

    To establish a sensitive and specific method for simultaneous determination of gestodene, etonogestrel and ethinylestradiol in plasma by LC-MS/MS, plasma samples were extracted and derivatized before injection. An ESI ion source was used and operated in the positive ion mode with multiple reaction monitoring (MRM). Norgestrel was chosen as internal standard and performed on a C18 (100 mm x 2.1 mm, 5 microm) column. The concentrations of gestodene, etonogestrel and ethinylestradiol were measured, using step-gradient mobile phase and step-gradient flow rate. The method was validated over the concentration range of 0.1-20 ng x mL(-1) for gestodene and etonogestrel and 0.01-2 ng x mL(-1) for ethinylestradiol, and showed excellent linearity. The intra- and inter-assay accuracy and precision were below 10.0% and recovery was 93.6%-110.9% over the three concentration levels evaluated. The method was applied in pharmacokinetic study of the compound gestodene patch and the compound etonogestrel patch in rabbits. The LC-MS/MS method was selective, accurate and sensitive, especially the LOQ were 100 pg x mL(-1) for gestodene and etonogestrel and 10 pg x mL(-1) for ethinylestradiol. The method was successfully applied in pharmacokinetic study for contraceptives.

  4. Improvement on simultaneous determination of chromium species in aqueous solution by ion chromatography and chemiluminescence detection

    DEFF Research Database (Denmark)

    Gammelgaard, Bente; Liao, Y.P.; Jons, O.

    1997-01-01

    A sensitive method for the simultaneous determination of chromium(III) and chromium(VI) was chromatography and chemiluminescence detection. Two Dionex ion-exchange guard columns in series, CG5 and AG7, were used to separate chromium(III) from chromium(VI). Chromium(VI) was reduced by potassium......, the stabilities of reductant and luminol solutions were studied. The linear range of the calibration curve for chromium(III) and chromium(VI) was 1-400 mu g l(-1). The detection limit was 0.12 mu g l(-1) for chromium(III) and 0.09 mu g l(-1) for chromium(VI), respectively. The precision at the 20 mu g l(-1) level...... was 1.4% for chromium(III) and 2.5% for chromium(VI), respectively. The accuracy of the chromium(III) determination was determined by analysis of the NIST standard reference material 1643c, Trace elements in water with the result 19.1 +/- 1.0 mu g Cr(III) l(-1) (certified value 19.0 +/- 0.6 mu g Cr...

  5. Simultaneous determination of Sunset yellow and Tartrazine in soft drinks using gold nanoparticles carbon paste electrode.

    Science.gov (United States)

    Ghoreishi, Sayed Mehdi; Behpour, Mohsen; Golestaneh, Mahshid

    2012-05-01

    The monitoring of synthetic dyes in foods is very important due to their potential harmfulness to human beings. Herein, a carbon-paste electrode (CPE) that is chemically modified with gold nanoparticles (nAu) was fabricated and used for the determination of Sunset yellow (SY) and Tartrazine (Tz). Cyclic and differential pulse voltammetry (CV and DPV) results revealed two well-resolved anodic peaks for SY and Tz with remarkably increase in oxidation signals of these colourants. Based on this, a novel electrochemical method was developed for the simultaneous determination of SY and Tz. High sensitivity and selectivity, sub-micromolar detection limit, high reproducibility and regeneration of the electrode surface by simple polishing make the nAu-CPE electrode very suitable for the determination of SY and Tz in commercially available soft drinks. The detection limits was 3.0×10(-8) and 2.0×10(-9)moll(-1) for SY and Tz, respectively, which are remarkably lower than those reported previously for SY and Tz using other modified electrodes. Copyright © 2011 Elsevier Ltd. All rights reserved.

  6. A method for simultaneous determination of wear-resistance of structurally identical machine parts with mutual friction

    International Nuclear Information System (INIS)

    Valigura, V.; Volyn'ski, A.

    1979-01-01

    There are mechanisms in the technique, boundary state of separate parts of which is determined by the process of wear of three elements of the mechanism, made of the same material (for example antifriction bearings). The main concept of wear determination in the case of such a mechanism is to conduct measurements by means of simultaneous application of three different methods, for example: the method of roentgen-fluorescence; the tracer technique with application of activation by means of irradiation by different elementary particles, practically by means of neutrons and protons; the method of artifical bases application. In the paper the method is presented having been developed in the Institute of Working Machines of the Poznan Polytechnic. This method of simultaneous investigation in the wear process of bearing rings, inner and outer, and rolling elements of roller bearings. All these elements of bearings are made of LX-15 steel. The method developed, permits to determine the wear sufficient for practical purposes sensitivity [ru

  7. Spectrophotometric and TLC-densitometric methods for the simultaneous determination of Ezetimibe and Atorvastatin calcium.

    Science.gov (United States)

    Baghdady, Yehia Z; Al-Ghobashy, Medhat A; Abdel-Aleem, Abdel-Aziz E; Weshahy, Soheir A

    2013-01-01

    Three sensitive methods were developed for simultaneous determination of Ezetimibe (EZB) and Atorvastatin calcium (ATVC) in binary mixtures. First derivative (D(1)) spectrophotometry was employed for simultaneous determination of EZB (223.8 nm) and ATVC (233.0 nm) with a mean percentage recovery of 100.23 ± 1.62 and 99.58 ± 0.84, respectively. Linearity ranges were 10.00-30.00 μg mL(-1) and 10.00-35.00 μg mL(-1), respectively. Isosbestic point (IS) spectrophotometry, in conjunction with second derivative (D(2)) spectrophotometry was employed for analysis of the same mixture. Total concentration was determined at IS, 224.6 nm and 238.6 nm over a concentration range of 10.00-35.00 μg mL(-1) and 5.00-30.00 μg mL(-1), respectively. ATVC concentration was determined using D(2) at 313.0 nm (10.00-35.00 μg mL(-1)) with a mean recovery percentage of 99.72 ± 1.36, while EZB was determined mathematically at 224.6 nm (99.75 ± 1.43) and 238.6 nm (99.80 ± 0.95). TLC-densitometry was employed for the determination of the same mixture; 0.10-0.60 μg band(-1) for both drugs. Separation was carried out on silica gel plates using diethyl ether-ethyl acetate (7:3 v/v). EZB and ATVC were resolved with Rf values of 0.78 and 0.13. Determination was carried out at 254.0 nm with a mean percentage recovery of 99.77 ± 1.30 and 99.86 ± 0.97, respectively. Methods were validated according to ICH guidelines and successfully applied for analysis of bulk powder and pharmaceutical formulations. Results were statistically compared to a reported method and no significant difference was noticed regarding accuracy and precision.

  8. Spectrophotometric and TLC-densitometric methods for the simultaneous determination of Ezetimibe and Atorvastatin calcium

    Directory of Open Access Journals (Sweden)

    Yehia Z. Baghdady

    2013-01-01

    Full Text Available Three sensitive methods were developed for simultaneous determination of Ezetimibe (EZB and Atorvastatin calcium (ATVC in binary mixtures. First derivative (D1 spectrophotometry was employed for simultaneous determination of EZB (223.8 nm and ATVC (233.0 nm with a mean percentage recovery of 100.23 ± 1.62 and 99.58 ± 0.84, respectively. Linearity ranges were 10.00–30.00 μg mL−1 and 10.00–35.00 μg mL−1, respectively. Isosbestic point (IS spectrophotometry, in conjunction with second derivative (D2 spectrophotometry was employed for analysis of the same mixture. Total concentration was determined at IS, 224.6 nm and 238.6 nm over a concentration range of 10.00–35.00 μg mL−1 and 5.00–30.00 μg mL−1, respectively. ATVC concentration was determined using D2 at 313.0 nm (10.00–35.00 μg mL−1 with a mean recovery percentage of 99.72 ± 1.36, while EZB was determined mathematically at 224.6 nm (99.75 ± 1.43 and 238.6 nm (99.80 ± 0.95. TLC-densitometry was employed for the determination of the same mixture; 0.10–0.60 μg band−1 for both drugs. Separation was carried out on silica gel plates using diethyl ether–ethyl acetate (7:3 v/v. EZB and ATVC were resolved with Rf values of 0.78 and 0.13. Determination was carried out at 254.0 nm with a mean percentage recovery of 99.77 ± 1.30 and 99.86 ± 0.97, respectively. Methods were validated according to ICH guidelines and successfully applied for analysis of bulk powder and pharmaceutical formulations. Results were statistically compared to a reported method and no significant difference was noticed regarding accuracy and precision.

  9. Simultaneous determination of Albendazol and Triclabendazol in Triclazol 22 suspension for veterinary purposes

    International Nuclear Information System (INIS)

    Garcia Penna, Caridad M.; Gafas Leyva, Maite; Rosales Bosch, Karina

    2013-01-01

    Triclazol 22 suspension containing triclabendazol and albendazol is used as parasiticide for veterinary purposes. to validate the analytical method for simultaneous determination of triclabendazol and albendazol in triclazol 22 suspension for quality control

  10. [Simultaneous onset of steroid-sensitive nephrotic syndrome and type 1 diabetes].

    Science.gov (United States)

    Rego Filho, Eduardo A; Mello, Solange F R; Omuro, André M; Loli, José O C

    2003-01-01

    We describe the case of a boy with steroid-sensitive nephrotic syndrome coexisting with type-1 diabetes mellitus. Nephrotic syndrome was diagnosed in a boy (age 3 years and 11 months) with generalized edema. Marked weight loss (23 to 16 kg), polyuria, polydipsia and weakness were observed after three weeks of treatment with prednisone 2 mg/kg/day. Diabetic ketoacidosis was confirmed by laboratory tests: hyperglycemia (glucose 657 mg/dl), glycosuria without proteinuria, acidosis and ketonuria. Therapy with insulin and prednisone was started. He was then maintained on a daily dose of NPH insulin. At age 4 years and 1 month a new episode of ketoacidosis without proteinuria occurred in association with a viral infection of the upper airways. At age 4 years and 4 months nephrotic syndrome relapsed, but the child responded well to steroid therapy. There was another relapse three months later, when prednisone treatment was interrupted. This led to the introduction of cyclophosphamide, with good results. Since then, the patient (now 5 years and 6 months old) has been taking insulin daily and nephrotic syndrome has not relapsed. Plasma levels of C3 and C4 and renal function are normal. Hematuria is occasionally present. Anti-GAD antibodies (glutamic decarboxilase) are normal and anti-islet cell antibodies are positive. HLA antigens: A2; B44; B52; DR4; DR8; DR53. The simultaneous occurrence of steroid-sensitive nephrotic syndrome and type-1 diabetes mellitus is rare.

  11. Extraction as a source of additional information when concentrations in multicomponent systems are simultaneously determined

    International Nuclear Information System (INIS)

    Perkov, I.G.

    1988-01-01

    Using as an example photometric determination of Nd and Sm in their joint presence, the possibility to use the influence of extraction on analytic signal increase is considered. It is shown that interligand exchange in extracts in combination with simultaneous determination of concentrations can be used as a simple means increasing the accuracy of determination. 5 refs.; 2 figs.; 3 tabs

  12. Amplified nanostructure electrochemical sensor for simultaneous determination of captopril, acetaminophen, tyrosine and hydrochlorothiazide.

    Science.gov (United States)

    Karimi-Maleh, Hassan; Ganjali, Mohammad R; Norouzi, Parviz; Bananezhad, Asma

    2017-04-01

    A novel nanomaterial-based voltammetric sensor has been developed for use a highly sensitive tool for the simultaneous determination of captopril (CA), acetaminophen (AC), tyrosine (TY) and hydrochlorothiazide (HCTZ). The device is based on the application of NiO/CNTs and (2-(3,4-dihydroxyphenethyl)isoindoline-1,3-dione) (DPID) to modify carbon paste electrodes. The NiO/CNTs nanocomposite was synthesized through a direct chemical precipitation approach and was characterized with X-ray powder diffraction (XRD), and scanning electron microscopy (SEM). The NiO/CNTs/DPID/CPEs were found to facilitate the analysis of CA, AC, TY and HCTZ in the concentration ranges of 0.07-200.0, 0.8-550.0, 5.0-750.0 and 10.0-600.0μM with the respective detection limits of 9.0nM, 0.3μM, 1.0μM and 5.0μM. The developed NiO/CNTs/DPID/CPEs were used for the determination of the mentioned analytes in pharmaceutical and biological real samples. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Spectrophotometric measurement of Cu(DDTC)2 for the simultaneous determination of zinc and copper.

    Science.gov (United States)

    Uddin, Mohammad Nasir; Salam, Md Abdus; Hossain, Mohammad Amzad

    2013-01-01

    A spectrophotometric procedure for the simultaneous determination of zinc(II) and copper(II) in a mixture using diethyldithiocarbamate (DDTC) as ligand has been described. Complexes formed with DDTC was extracted with CHCl(3)/CCl(4) and the absorbance was measured at 435 nm which is equivalent of Cu(II) in sample only as Zn(DDTC)(2) has no absorption. Zinc measurement is based on the quantitative displacement of zinc from Zn(DDTC)(2) by Cu(II) with the addition of excess copper(II) to the extract. The absorbance is measured again where additional absorbance is equivalent to zinc. The molar absorptivity and sandall's sensitivity at this wavelength are 2.86×10(5) mol(-1) L cm(-1) and 3.076 ng cm(-2), respectively. Reproducibility with in 4% and detection limits of 0.29 μg mL(-1) was obtained. Linear calibration range was 0.2-14 μg mL(-1) for zinc and 0.2-12 μg mL(-1) for copper with the regression coefficient (r(2)) 0.998 for each. In the presence of a suitable masking agent (EDTA) very good selectivity was achieved. The method was extended to the determination of zinc and copper in a number of environmental water and soil samples, biological, pharmaceutical, fertilizer and food samples. Copyright © 2012 Elsevier Ltd. All rights reserved.

  14. Simultaneous determination of monosaccharides and oligosaccharides in dates using liquid chromatography-electrospray ionization mass spectrometry.

    Science.gov (United States)

    Ghfar, Ayman A; Wabaidur, Saikh M; Ahmed, A Yacine Badjah Hadj; Alothman, Zeid A; Khan, Mohammad R; Al-Shaalan, Nora H

    2015-06-01

    Ultra performance liquid chromatography coupled to mass spectrometry was used for the simultaneous separation and determination of reducing monosaccharides (fructose and glucose), a non-reducing disaccharide (sucrose) and oligosaccharides (kestose and nystose) in HILIC mode. The chromatographic separation of all saccharides was performed on a BEH amide column using an acetonitrile-water gradient elution. The detection was carried out using selected ion recording (SIR) acquisition mode. The validation of the proposed method showed that the limit of detection and limit of quantification values for the five analyzed compounds were in the range of 0.25-0.69μg/mL and 0.82-3.58μg/mL, respectively; while the response was linear in the range of 1-50μg/mL. The developed method showed potential usefulness for a rapid and sensitive analysis of underivatized saccharides and was used for determination of sugars in three date samples (Sefri, Mabroom, Ghassab) which were soxhlet extracted by ethanol. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. Simultaneous determination of olanzapine and fluoxetine hydrochloride in capsules by spectrophotometry, TLC-spectrodensitometry and HPLC.

    Science.gov (United States)

    Tantawy, Mahmoud A; Hassan, Nagiba Y; Elragehy, Nariman A; Abdelkawy, Mohamed

    2013-03-01

    This paper describes sensitive, accurate and precise spectrophotometric, TLC-spectrodensitometric and high performance liquid chromatographic (HPLC) methods for simultaneous determination of olanzapine and fluoxetine HCl. Two spectrophotometric methods were developed, namely; first derivative (D (1)) and derivative ratio (DD (1)) methods. The TLC method employed aluminum TLC plates precoated with silica gel GF254 as the stationary phase and methanol:toluene:ammonia (7:3:0.1, by volume) as the mobile phase, where the chromatogram was scanned at 235 nm. The developed HPLC method used a reversed phase C18 column with isocratic elution. The mobile phase composed of phosphate buffer pH 4.0:acetonitrile:triethylamine (53:47:0.03, by volume) at flow rate of 1.0 mL min(-1). Quantitation was achieved with UV detection at 235 nm. The methods were validated according to the International Conference on Harmonization (ICH) guidelines. The selectivity of the proposed methods was tested using laboratory-prepared mixtures. The developed methods were successfully applied for the determination of olanzapine and fluoxetine HCl in bulk powder and combined capsule dosage form.

  16. Individual and simultaneous determinations of phenothiazine drugs using PCR, PLS and (OSC–PLS multivariate calibration methods

    Directory of Open Access Journals (Sweden)

    REZA BEHJATMANESH-ARDAKANI

    2008-02-01

    Full Text Available Individual and simultaneous determinations of some phenothiazine drugs are described. The individual determination method is based on the reaction of chlorpromazine hydrochloride (CPH, promethazine hydrochloride (PH, trifluoperazine hydrochloride (TFPH, trimipramine maleate (TPM and thioridazine hydrochloride (TRDH with complex of [Fe(Bpy3]3+. In the presence of phenothiazine derivatives, [Fe(Bpy3]3+ is reduced easily to the coloured complex [Fe(Bpy3]2+, which shows an absorption maximum at 525 nm. The individual method is highly sensitive and suitable for 0.3–190 mg ml-1 concentrations, with detection limits in the range 0.18–2.46 mg ml-1. Simultaneous kinetic–spectrophotometric determination of ternary mixture of CPH, PH and TPM using principal component regression (PCR, partial least squares (PLS and orthogonal signal correction (OSC–PLS multivariate calibration methods is also described. The simultaneous methods are based on the difference observed in the reduction rate of the [Fe(Bpy3]3+ complex with CPH, PH and TPM in acidic media. The results showed that the simultaneous determination of CPH, PH and TPM can be performed in the concentration ranges of 0.5–120.0, 0.3–80.0 and 5.0–100.0 µg ml-1, respectively, for three methods (PCR, PLS and OSC–PLS. The root mean square errors of prediction (RMSEP of CPH, PH and TPM were 0.346, 0.663 and 0.820 (for PCR 0.317, 0.659 and 0.830 (for PLS and 0.087, 0.124 and 0.085 (for OSC–PLS, respectively. The proposed methods were successfully applied to the individual and simultaneous determination of phenothiazine derivatives in pharmaceutical preparations, the results of which compared well with those obtained by the official method, and several synthetic (spiked samples, whereby satisfactory results were obtained.

  17. Different Chromatographic Methods for Simultaneous Determination of Mefenamic Acid and Two of Its Toxic Impurities.

    Science.gov (United States)

    Morcoss, Martha M; Abdelwahab, Nada S; Ali, Nouruddin W; Elsaady, Mohammed T

    2017-08-01

    Two sensitive, accurate and precise chromatographic methods mentioned as TLC-densitometric method and RP-HPLC-DAD method, were developed and validated for the simultaneous determination of mefenamic acid (MEF) and its two toxic impurities, benzoic acid (BA) and 2,3-dimethylaniline (DMA). In the proposed TLC-densitometric method a developing system consisting of chloroform:acetone:acetic acid:ammonia solution(70:30:2:2, v/v/v/v) was used, TLC aluminum plates 60 F254 was used as a stationary phase and the separated bands were UV-scanned at 225 nm. While the proposed RP-HPLC-DAD method depended on chromatographic separation on C18 column using 0.05 M KH2PO4 buffer: acetonitrile (40:60, v/v) as a mobile phase at constant flow rate of 1 mL/min with UV detection at 225 nm. Linear relationships were obtained in the ranges of 0.3-2, 0.3-2 and 0.3-1.8 μg/band (for TLC-densitometric method) and in the ranges of 7-50, 10-50 and 7-50 μg/mL (for HPLC-DAD method) for MEF, BA and DMA, respectively. Factors affecting the developed methods have been studied and optimized. Moreover ,the proposed methods were successfully applied for determination of the studied drug in its pharmaceutical dosage form. The methods showed no significance difference when compared with the reported method using F-test and Student's-t test. The low of detection and quantization limits of the proposed methods get them suitable for quality control and stability studies of MEF in pharmaceutical formulation. The developed methods have advantages of being more selective and sensitive than the published methods. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  18. Simultaneous determination of oxygen, nitrogen and hydrogen in metals by pulse heating and time of flight mass spectrometric method.

    Science.gov (United States)

    Shen, Xuejing; Wang, Peng; Hu, Shaocheng; Yang, Zhigang; Ma, Hongquan; Gao, Wei; Zhou, Zhen; Wang, Haizhou

    2011-05-30

    The inert gas fusion and infrared absorption and thermal conductivity methods are widely used for quantitative determination of oxygen(O), nitrogen(N) and hydrogen(H) in metals. However, O, N and H cannot be determined simultaneously with this method in most cases and the sensitivity cannot meet the requirement of some new metal materials. Furthermore, there is no equipment or method reported for determination of Argon(Ar) or Helium(He) in metals till now. In this paper, a new method for simultaneous quantitative determination of O, N, H and Ar(or He) in metals has been described in detail, which combined the pulse heating inert gas fusion with time of flight mass spectrometric detection. The whole analyzing process was introduced, including sample retreatment, inert gas fusion, mass spectral line selection, signal acquisition, data processing and calibration. The detection limit, lower quantitative limit and linear range of each element were determined. The accuracy and precision of the new method have also been verified by measurements of several kinds of samples. The results were consistent with that obtained by the traditional method. It has shown that the new method is more sensitive and efficient than the existing method. Copyright © 2011 Elsevier B.V. All rights reserved.

  19. Simultaneous spectrophotometric determination of lamivudine and zidovudine in fixed dose combinations using multivariate calibration

    Directory of Open Access Journals (Sweden)

    Severino Grangeiro Jr.

    2011-01-01

    Full Text Available The simultaneous determination of two or more active components in pharmaceutical preparations, without previous chemical separation, is a common analytical problem. Published works describe the determination of AZT and 3TC separately, as raw material or in different pharmaceutical preparations. In this work, a method using UV spectroscopy and multivariate calibration is described for the simultaneous measurement of 3TC and AZT in fixed dose combinations. The methodology was validated and applied to determine the AZT+3TC contents in tablets from five different manufacturers, as well as their dissolution profile. The results obtained employing the proposed methodology was similar to methods using first derivative technique and HPLC.

  20. Simultaneous determination of uranium and thorium with Arsenazo III by second-derivative spectrophotometry

    International Nuclear Information System (INIS)

    Kuroda, Rokuro; Kurosaki, Mayumi; Hayashibe, Yutaka; Ishimaru, Satomi

    1990-01-01

    A derivative spectrophotometric method has been developed for the simultaneous determination of microgram quantities of uranium and thorium with Arsenazo III in hydrochloric acid medium. The second-derivative absorbances of the uranium and thorium Arsenazo III complexes at 679.5 and 684.4 nm are used for their quantification. Uranium and thorium, both in the range 0.1-0.7 μg/ml have been determined simultaneously with good precision. The procedure does not require separation of uranium and thorium, and allows the determination of both metals in the presence of alkaline-earth metals and zirconium, but lanthanides interfere. (author)

  1. Simultaneous determination of acetylsalicylic acid and caffeine in pharmaceutical formulation by first derivative synchronous fluorimetric method.

    Science.gov (United States)

    Karim, Mohammad Mainul; Jeon, Chi Wan; Lee, Hyun Sook; Alam, Seikh Mafiz; Lee, Sang Hak; Choi, Jong Ha; Jin, Seung Oh; Das, Ajoy Kumar

    2006-09-01

    A sensitive, rapid, and specific assay has been developed for the simultaneous determination of acetylsalicylic acid and caffeine in commercial tablets based on their natural fluorescence. The mixture of these drugs was resolved by first derivative synchronous fluorimetric technique using two scans. At Deltalambda=106 nm, using first derivative synchronous scanning, only acetylsalicylic acid yields a detectable signal at 316 nm (peak to zero method) which is unaffected by caffeine. At Deltalambda=30 nm, the signal of caffeine at 288 nm (peak to zero method) is not affected by acetylsalicylic acid. The range of application is between 0.021 and 41.62 microg ml(-1) (correlation coefficient, R=0.9995) for acetylsalicylic acid and between 0.4486 and 44.86 microg ml(-1) (correlation coefficient, R=0.99786) for caffeine. The recovery range of 98.40-102% for acetylsalicylic acid and 90-100.5% for caffeine from their synthetic mixture was reported. Overall recovery of both compounds about 97-99% for acetylsalicylic acid and 97-98% for caffeine was obtained from real sample analysis. The detection limits are 0.0013 microg ml(-1) and 0.0306 microg ml(-1) for acetylsalicylic acid and caffeine, respectively. The relative standard deviation (n=10) for 20 microg ml(-1) of acetylsalicylic acid is 2.75% and for 2.2 microg ml(-1)of caffeine is 1.7%.

  2. Fractionation of human serum lipoproteins and simultaneous enzymatic determination of cholesterol and triglycerides

    Energy Technology Data Exchange (ETDEWEB)

    Qureshi, Rashid Nazir [Polymer-Analysis Group, van' t Hoff Institute for Molecular Sciences, University of Amsterdam, Nieuwe Achtergracht 166, 1018WV Amsterdam (Netherlands); Kok, Wim Th., E-mail: W.Th.Kok@uva.nl [Polymer-Analysis Group, van' t Hoff Institute for Molecular Sciences, University of Amsterdam, Nieuwe Achtergracht 166, 1018WV Amsterdam (Netherlands); Schoenmakers, Peter J. [Polymer-Analysis Group, van' t Hoff Institute for Molecular Sciences, University of Amsterdam, Nieuwe Achtergracht 166, 1018WV Amsterdam (Netherlands)

    2009-11-03

    A method based on Asymmetric Flow Field-Flow Fractionation (AF4) was developed to separate different types of lipoproteins from human serum. The emphasis in the method optimization was on the possibilities to characterize the largest lipoprotein fractions (LDL and VLDL), which is usually not possible with the size-exclusion chromatography methods applied in routine analysis. Different channel geometries and flow programs were tested and compared. The use of a short fractionation channel was shown to give less sample dilution at the same fractionation power compared to a conventional, long channel. Different size selectivities were obtained with an exponential decay and a linear cross flow program. The ratio of the UV absorption signal to the light scattering signal was used to validate the relation between retention time and size of the fractionated particles. An experimental setup was developed for the simultaneous determination of the cholesterol and triglycerides distribution over the lipoprotein fractions, based on enzymatic reactions followed by UV detection at 500 nm. Coiled and knitted PTFE tubing reactors were compared. An improved peak sharpness and sensitivity were observed with the knitted tubing reactor. After optimization of the experimental conditions a satisfactory linearity and precision (2-3% rsd for cholesterol and 5-6% rsd for triglycerides) were obtained. Finally, serum samples, a pooled sample from healthy volunteers and samples of sepsis patients, were analyzed with the method developed. Lipoprotein fractionation and cholesterol and triglyceride distributions could be correlated with the clinical background of the samples.

  3. A Validated HPLC-DAD Method for Simultaneous Determination of Etodolac and Pantoprazole in Rat Plasma

    Directory of Open Access Journals (Sweden)

    Ali S. Abdelhameed

    2014-01-01

    Full Text Available A simple, sensitive, and accurate HPLC-DAD method has been developed and validated for the simultaneous determination of pantoprazole and etodolac in rat plasma as a tool for therapeutic drug monitoring. Optimal chromatographic separation of the analytes was achieved on a Waters Symmetry C18 column using a mobile phase that consisted of phosphate buffer pH~4.0 as eluent A and acetonitrile as eluent B in a ratio of A : B, 55 : 45 v/v for 6 min, pumped isocratically at a flow rate of 0.8 mL min−1. The eluted analytes were monitored using photodiode array detector set to quantify samples at 254 nm. The method was linear with r2=0.9999 for PTZ and r2=0.9995 for ETD at a concentration range of 0.1–15 and 5–50 μgmL−1 for PTZ and ETD, respectively. The limits of detection were found to be 0.033 and 0.918 μgmL−1 for PTZ and ETD, respectively. The method was statistically validated for linearity, accuracy, precision, and selectivity following the International Conference for Harmonization (ICH guidelines. The reproducibility of the method was reliable with the intra- and interday precision (% RSD <7.76% for PTZ and <7.58 % for ETD.

  4. Simultaneous Determination of Four Compounds in a Nelumbo nucifera Seed Embryo by HPLC-DAD

    Directory of Open Access Journals (Sweden)

    Gahee Ryu

    2017-01-01

    Full Text Available Nelumbo nucifera has a variety of biological activities. So it was importantly used as various herbal medicines since traditional times. A simple, fast, and sensitive high-performance liquid chromatographic (HPLC method was developed in this study for efficient quality control of N. nucifera. Four different compounds, including neferine, 1,2,3,4-tetrahydro-1-[(4-hydroxyphenyl methyl]-2-methyl-7-isoquinolinol, 1-hydroxy-2-methylpropene, and 3-(prop-1-enylbenzene-1,2,4,5-tetrol, were simultaneously determined. The four compounds were isolated through a Dionex C18 column by gradient elution with 0.1% TFA-water and methanol. The flow rate was 1.0 mL/min, and the wavelength was detected at 205, 254, 280, and 330 nm. The chromatograms were acquired at 205 nm. The four compounds showed good linear relationships (r2>0.96 over five different concentrations, and an average recovery of the method ranged from 96.27% to 108.78%. Through the analysis validation test and application of the method, the optimized conditions verified that it is efficient to isolate the compounds of N. nucifera seed embryos.

  5. Simultaneous determination of niacin, niacinamide and nicotinuric acid in human plasma.

    Science.gov (United States)

    Pfuhl, P; Kärcher, U; Häring, N; Baumeister, A; Tawab, Mona Abdel; Schubert-Zsilavecz, M

    2005-01-04

    A sensitive, specific, accurate, and reproducible HPLC/MS-method for the simultaneous quantitative determination of niacin (NA) and its main metabolites niacinamide (NAM) and nicotinuric acid (NUR) in human plasma using chinolin-3-carboxylic acid as an internal standard was developed and validated according to international guidelines for method validation. All analytes and the internal standard were separated from acidified plasma by solid phase extraction. Afterwards the extracted samples were analyzed by HPLC/MS in the positive electrospray ionization mode (ESI) and selected ion monitoring (SIM). The total run time was 7 min between injections. The assay had a lower limit of quantification of 50.0 ng/mL for each analyte using 1 mL of plasma. The calibration curves were linear in the measured range between 50.0 and 750 ng/mL plasma. The overall precision and accuracy for all concentrations of quality controls and standards was better than 15%. No indications were found for possible instabilities of niacin, niacinamide and nicotinuric acid in plasma at -20 degrees C, in the extraction solvent or after repeated thawing/freezing cycles. In stabilities were observed in whole blood and in plasma at room temperature. The recovery of the extraction method ranged from 86 to 89% for the three analytes.

  6. Simultaneous determination of five Alternaria toxins in cereals using QuEChERS-based methodology.

    Science.gov (United States)

    Zhou, Jian; Xu, Jiao-Jiao; Cai, Zeng-Xuan; Huang, Bai-Fen; Jin, Mi-Cong; Ren, Yi-Ping

    2017-11-15

    Two analytical approaches, including ultra-high performance liquid chromatograph linked with photo-diode array/fluorescence detector, and ultra-high performance liquid chromatography-tandem mass spectrometry, have been proposed for simultaneous determination of five Alternaria toxins in cereals, which both based on QuEChERS strategy. After QuEChERS extraction and salting out, the collected supernatant was subjected to an extra dispersive liquid-liquid microextraction step prior to quantitative analysis. Response surface methodology based on central composite design was employed to optimize the micro-extraction conditions. During photo-diode array/fluorescence detector method validation, satisfactory analytical characteristics, in terms of selectivity, recovery (72.7%-109.1%), precision (inter-day RSDs <9.6%), sensitivity (limits of quantification ranged from 2.1μgkg -1 to 120.0μgkg -1 ) and linearity (R 2 all higher than 0.9984), were achieved. Mass spectrometry method was employed as a certified method for accuracy. The two methodologies were successfully applied to 71 samples including three different matrices and the quantitative results were compared. As the result of non-parametric test shown, the established two analytical approach exhibited comparable quantitative accuracy to each other. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Derivative emission spectrofluorimetry for the simultaneous determination of guaifenesin and phenylephrine hydrochloride in pharmaceutical tablets.

    Science.gov (United States)

    Maher, Hadir M; Alshehri, Mona M; Al-taweel, Shorog M

    2015-05-01

    Rapid, simple and sensitive derivative emission spectrofluorimetric methods have been developed for the simultaneous analysis of binary mixtures of guaifenesin (GUA) and phenylephrine hydrochloride (PHE). The methods are based upon measurement of the native fluorescence intensity of the two drugs at λex = 275 nm in methanolic solutions, followed by differentiation using first (D1) and second (D2) derivative techniques. The derivative fluorescence intensity-concentration plots were rectilinear over a range of 0.1-2 µg/mL for both GUA and PHE. The limits of detection were 0.027 (D1, GUA), 0.025 (D2, GUA), 0.031 (D1, PHE) and 0.033 (D2, PHE) µg/mL and limits of quantitation were 0.089 (D1, GUA), 0.083 (D2, GUA), 0.095 (D1, PHE) and 0.097 (D2, PHE) µg/mL. The proposed derivative emission spectrofluorimetric methods (D1 and D2) were successfully applied for the determination of the two compounds in binary mixtures and tablets with high precision and accuracy. The proposed methods were fully validated as per ICH guidelines. Copyright © 2014 John Wiley & Sons, Ltd.

  8. Simultaneous determination of atorvastatin calcium, ezetimibe, and fenofibrate in a tablet formulation by HPLC.

    Science.gov (United States)

    Patel, Archita; Macwana, Chhaya; Parmar, Vishal; Patel, Samir

    2012-01-01

    An accurate, simple, reproducible, and sensitive HPLC method was developed and validated for the simultaneous determination of atorvastatin calcium, ezetimibe, and fenofibrate in a tablet formulation. The analyses were performed on an RP C18 column, 150 x 4.60 mm id, 5 pm particle size. The mobile phase methanol-acetonitrile-water (76 + 13 + 11, v/v/v), was pumped at a constant flow rate of 1 mL/min. UV detection was performed at 253 nm. Retention times of atorvastatin calcium, ezetimibe, and fenofibrate were found to be 2.25, 3.68, and 6.41 min, respectively. The method was validated in terms of linearity, precision, accuracy, LOD, LOQ, and robustness. The response was linear in the range 2-10 microg/mL (r2 = 0.998) for atorvastatin calcium, 2-10 microg/mL (r2 = 0.998) for ezetimibe, and 40-120 microg/mL (r2 = 0.998) for fenofibrate. The developed method can be used for routine quality analysis of the drugs in the tablet formulation.

  9. Simultaneous determination of oxygen and cadmium in cadmium and cadmium compounds

    International Nuclear Information System (INIS)

    Imaeda, K.; Kuriki, T.; Ohsawa, K.; Ishii, Y.

    1977-01-01

    Cadmium and its compounds were analysed for oxygen and cadmium by a modification of the Schutze-Unterzaucher method. Oxygen in some compounds such as cadmium oxide, nitrate and sulphate could not be determined by the usual method. The method of adding carbon was employed for the determination of total oxygen. Total oxygen could be determined by the addition of 5 mg of carbon to a sample boat and heating at 950 0 . The determination was also carried out by addition of naphthalene (2 mg). It was found that the cadmium powder and cadmium flake used contained ca. 1 and 0.15% oxygen, respectively. Oxygen and cadmium in cadmium and its compounds were simultaneously determined by the addition of 2 mg of naphthalene. Cadmium was determined colorimetrically by use of glyoxal-bis-(2-hydroxyanil). Oxygen and cadmium in the samples could be determined simultaneously with an average error of -0.02 and -0.22%, respectively. (author)

  10. Four Spectrophotometric Methods For Simultaneous Determination Of Carbamazepine And Lamotrigine In Binary Mixtures And Urine Samples

    International Nuclear Information System (INIS)

    Najib, F.M.; Mustafa, M.S.

    2014-01-01

    In this work four different UV-spectrophotometric methods are described for simultaneous determination of antiepileptic drugs; carbamazepine (CBZ) and lamotrigine (LMT) in binary synthetic mixtures and urine samples without separation. First method was by solving the two simultaneous equations (SEQ) based on total absorbance according to Beers law. Second was Dual wavelength (DWSP) method; Absorbance difference between 304 and 313 nm was measurable for CBZ but was zero for LMT. Likewise the absorbance difference between 282 and 290 nm was significant for LMT, and zero for CBZ. Third involved the use of zero- crossing first derivative method (ZCDSP) using the amplitudes at 308.9 and 286.6 nm for CBZ and LMT respectively. Ratio Derivative Spectrophotometry (RDSP) was the last. Here, the absorbance at different concentrations of CBZ or LMT, was divided, wavelength by wavelength, by the absorbance of a divisor, which was LMT standard for the analyte CBZ, and vice versa for LMT, (Divisor=2.0 μg.mL -1 ) in both cases. The amplitude of the derivative ratio spectra at 290 nm with wavelength interval (Δλ=6.0nm) and 328 nm (Δλ=4.0 nm) were selected for the determination of CBZ and LMT respectively. CBZ and LMT were simultaneously determined in synthetic mixtures and urine samples by the four methods giving good linearity, r 2 ranged between 0.9990 - 0.9997. Detection Limit (D.L) was mostly less than 0.4 μg.mL -1 ,while in case of ZCDSP and RDSP were between 0.01-0.2 μg.mL -1 with wider linearity range (1-50 for CBZ and 1 - 80 μg.mL -1 for LMT). A slightly lower sensitivity was observed when suppressing solution for urine analysis was used to remove interferences. The recoveries of CBZ and LMT in samples of urine of a healthy person spiked with the drugs and using urine of a healthy person as a blank were, in most cases, around (101.0 % - 103.33 %) and (98.33 % - 102.16 %) with RSD≤3.61 and 3.63 % for CBZ and LMT respectively. The recoveries using suppressing

  11. Simultaneous Determination of Hydroquinone and Catechol by Poly (L-methionine Coated Hydroxyl Multiwalled Carbon Nanotube Film

    Directory of Open Access Journals (Sweden)

    Ying Zhang

    2014-07-01

    Full Text Available A simply and high selectively electrochemical method has been developed for the simultaneous determination of hydroquinone and catechol at a glassy carbon electrode modified with the poly L-methionine/multiwall carbon nanotubes, which significantly increased the reversible electrochemical reaction. The electrochemical behavior of catechol and hydroquinone at the modified electrode was studied by cyclic voltammetry and differential pulse voltammetry. The presence of hydroxyl MWCNTs in the composite film enhances the surface coverage concentration of poly L- methionine/multiwall carbon nanotubes. The results suggest that pH=6 is the optimum acidity condition for the selective and simultaneous determination of catechol and hydroquinone. Under the optimized condition, the response peak currents of the modified electrodes were linear over ranges of 8.0´10-7~2.0´10-4 mol/L (R2=0.997 for hydroquinone and 8.0´10-7~2.0´10-4, R2=0.997 for catechol. The sensor also exhibited good sensitivity with the detection limit of 8.0´10-8 mol/L and 1.0´10- 7 mol/L for hydroquinone and catechol, respectively. This study provides a new kind of composite modified electrode for electrochemical sensors with good selectivity and strong anti- interference. It has been applied to simultaneous determination of hydroquinone and catechol in water sample with simplicity and high selectivity.

  12. Simultaneous determination of potassium and nitrate ions in mouthwashes using sequential injection analysis with potentiometric detection.

    Science.gov (United States)

    Zárate, N; Irazu, E; Araújo, A N; Montenegro, M C B S M; Pérez-Olmos, R

    2008-06-01

    Two methods for the determination of potassium nitrate in mouthwashes, used against dentin hypersensitivity, have been simultaneously implemented in an sequence injection analysis (SIA) system. In addition to in-line dilution of the samples, the equipment simultaneously detected potassium and nitrate using two tubular potentiometric detectors, selective to each ion, providing a real-time assessment of the quality of the results. Both determinations were shown to be precise and accurate and the obtained results do not statistically differ from those furnished by applying the AES and HPLC reference methods.

  13. Simultaneous determination of ochratoxin A, mycophenolic acid and fumonisin B-2 in meat products

    DEFF Research Database (Denmark)

    Sørensen, Louise Marie; Mogensen, Jesper; Nielsen, Kristian Fog

    2010-01-01

    Here we present a method for simultaneous determination of the fungal metabolites mycophenolic acid, ochratoxin A (OTA) and fumonisin B-2 (FB2) in meat products. Extraction was performed with water-acetonitrile, followed by acetone-induced precipitation of salts and proteins. Purification...

  14. Simultaneous Determination of Arsenic, Manganese, and Selenium in Biological Materials by Neutron-Activation Analysis

    DEFF Research Database (Denmark)

    Heydorn, Kaj; Damsgaard, Else

    1973-01-01

    A new method was developed for the simultaneous determination of arsenic, manganese, and selenium in biological material by thermal-neutron activation analysis. The use of 81 mSe as indicator for selenium permitted a reduction of activation time to 1 hr for a 1 g sample, and the possibility of loss...

  15. A universal gamma-gamma method for simultaneous determination of rock and ore properties

    International Nuclear Information System (INIS)

    Charbucinski, J.

    1983-01-01

    A method for the simultaneous determination of heavy element content, density, borehole diameter and grain size is described, which is based on investigation of the changes in spectrum shape. By analysing these changes in a quantitative manner, information regarding the physical parameters of the medium can be obtained. The results of laboratory tests of the method are presented. (author)

  16. Simultaneous Determination of Atorvastatin and Amlodipine in Industrial Tablets by Apparent Content Curve and HPLC Methods

    Directory of Open Access Journals (Sweden)

    Imre Silvia

    2013-02-01

    Full Text Available Introduction: This study proposes the simultaneous determination of atorvastatin and amlodipine in industrial tablets by a quantitative spectrophotometric method, named the apparent content curve method, test method, and by an HPLC method with UV detection as reference method.

  17. Simultaneous Determination of Binding Constants for Multiple Carbohydrate Hosts in Complex Mixtures

    DEFF Research Database (Denmark)

    Meier, Sebastian; Beeren, Sophie

    2014-01-01

    We describe a simple method for the simultaneous determination of association constants for a guest binding to seven different hosts in a mixture of more than 20 different oligosaccharides. If the binding parameters are known for one component in the mixture, a single NMR titration suffices...

  18. Capillary hydrophilic interaction chromatography/mass spectrometry for simultaneous determination of multiple neurotransmitters in primate cerebral cortex.

    Science.gov (United States)

    Zhang, Xiaozhe; Rauch, Alexander; Lee, Han; Xiao, Hongbin; Rainer, Gregor; Logothetis, Nikos K

    2007-01-01

    A diverse array of neurotransmitters and neuromodulators control and affect brain function. A profound understanding of the signaling pathways and the neural circuits underlying behavior is therefore likely to require the tracking of concentration changes of active neurochemicals. In the present study, we demonstrate the feasibility of a method allowing the simultaneous determination of the concentrations of six neurotransmitters: acetylcholine, serotonin, dopamine, gamma-aminobutyric acid (GABA), glutamate and aspartate, in the extracellular brain fluid (EBF). We used hydrophilic interaction chromatography (HILIC) coupled to tandem mass spectrometry (MS/MS) to analyze the EBF from the monkey brain. A push-pull sampling method was used to collect EBF from the prefrontal cortex (PFC) of conscious monkeys at flow rates in the range of low nL/min. The detection limits of acetylcholine, serotonin, dopamine, GABA, glutamate and aspartate were 0.015, 0.15, 0.3, 1.2, 6 and 15 femtomoles, respectively, allowing us to quantitatively determine the concentrations of these six neurotransmitters simultaneously from 500 nL in vivo samples. We conclude that HILIC/MS/MS combined with the push-pull sampling method represents a sensitive technique for simultaneous monitoring of neurotransmitters from EBF samples. Copyright 2007 John Wiley & Sons, Ltd.

  19. Novel methodologies for automatically and simultaneously determining BTEX components using FTIR spectra.

    Science.gov (United States)

    Wang, Liang; Liu, Erming; Cheng, Ying; Bekele, Dawit N; Lamb, Dane; Chen, Zuliang; Megharaj, Mallavarapu; Naidu, Ravendra

    2015-11-01

    This study introduced a patented novel methodological system for automatically analysis of Fourier Transform Infrared Spectrometer (FTIR) spectrum data located at 'fingerprint' region (wavenumber 670-800 cm(-1)), to simultaneously determinate multiple petroleum hydrocarbons (PHs) in real mixture samples. This system includes: an object oriented baseline correction; Band decomposition (curve fitting) method with mathematical optimization; and Artificial Neural Network (ANN) for determination, which is suitable for the characteristics of this IR regions, where the spectra are normally with low signal to noise ratio and high density of peaks. BTEX components are potentially lethal carcinogens and contained in many petroleum products. As a case study, six BTEX components were determinate automatically and simultaneously in mixture vapor samples. The robustness of the BTEX determination was validated using real petroleum samples, and the prediction results were compared with gas chromatography-mass spectrometry (GC-MS). Copyright © 2015 Elsevier B.V. All rights reserved.

  20. Simultaneous determination of L-tyrosine and caffeine based on their electrocatalytic oxidation at a 4-tert-butylcalix[6] arene-modified carbon paste electrode.

    Science.gov (United States)

    Srivastava, Ashwini K; Gaichore, Reena R

    2013-01-01

    Simultaneous determination of L-tyrosine and caffeine was performed at a carbon paste electrode modified with 4-tert-butylcalix[6]arene and in situ Ni2+ ions. Surface characterization of the electrode was carried out by means of scanning electron microscopy. Electrochemical impedance diagnosis revealed that oxidation of both molecules is kinetically facile on the modified electrode. The electrochemical behavior of both molecules was studied using cyclic voltammetry, and further quantified using differential pulse voltammetry (DPV). The results revealed a high sensitivity for their simultaneous detection. DPV allowed simultaneous detection of L-tyrosine and caffeine in the range of 10(-6) to 10(-3) M, with LODs of 2.19 x 10(-7) and 4.03 x 10(-7) M, respectively. The modified electrode was used for individual determination of L-tyrosine and caffeine in various pharmaceutical formulations and simultaneous monitoring in human body fluids.

  1. Simultaneous determination of psychotropic drugs in human urine by capillary electrophoresis with electrochemiluminescence detection

    Energy Technology Data Exchange (ETDEWEB)

    Li Jianguo [Key Laboratory of Analytical Chemistry for Life Science (Education Ministry of China), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093 (China); School of Chemistry and Chemical Engineering, Suzhou University, Suzhou 215006 (China); Zhao Fengjuan [Key Laboratory of Analytical Chemistry for Life Science (Education Ministry of China), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093 (China); Ju Huangxian [Key Laboratory of Analytical Chemistry for Life Science (Education Ministry of China), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093 (China)]. E-mail: hxju@nju.edu.cn

    2006-08-04

    Amitriptyline, doxepin and chlorpromazine are often used as psychotropic drugs in treatment of the various mental diseases, and are also partly excreted by kidney. This work developed a simple, selective and sensitive method for their simultaneous monitoring in human urine using capillary electrophoresis coupled with electrochemiluminescence (ECL) detection based on end-column ECL reaction of tris-(2,2'-bipyridyl)ruthenium(II) with aliphatic tertiary amino moieties. Acetone was used as an additive to the running buffer to obtain their absolute separation. Under optimized conditions the proposed method displayed a linear range from 5.0 to 800 ng mL{sup -1} for the three drugs with the correlation coefficients more than 0.995 (n = 8). Their limits of detection were 0.8 ng mL{sup -1} (3.6 fg), 1.0 ng mL{sup -1} (4.5 fg) and 1.5 ng mL{sup -1} (6.8 fg) at a signal to noise ratio of 3, respectively. The relative standard deviations for five determinations of 20 ng mL{sup -1} amitriptyline, doxepin and chlorpromazine were 1.7%, 4.2% and 3.6%, respectively. For practical application an extract step with 90:10 heptane/ethyl acetate (v/v) was performed to eliminate the influence of ionic strength in sample. The recoveries of amitriptyline, doxepin and chlorpromazine at different levels in human urine were between 83% and 93%, which showed that the method was valuable in clinical and biochemical laboratories for monitoring amitriptyline, doxepin and chlorpromazine.

  2. Development and evaluation of a liquid chromatography tandem mass spectrometry method for simultaneous determination of salivary melatonin, cortisol and testosterone.

    Science.gov (United States)

    Jensen, Marie Aarrebo; Hansen, Ase Marie; Abrahamsson, Peter; Nørgaard, Asger W

    2011-09-01

    Circadian disruption can have several possible health consequences, but is not well studied. In order to measure circadian disruption, in relation to shift or night work, we developed a simple and sensitive method for the simultaneous determination of melatonin, cortisol and testosterone in human saliva. We used liquid-liquid extraction (LLE) followed by liquid chromatography coupled to electrospray tandem mass spectrometry (LC-ESI-MS/MS) recorded in positive ion mode. Saliva samples were collected by spitting directly into tubes and 250 μL were used for analysis. The limits of detection were 4.1 pmol/L, 0.27 nmol/L and 10.8 pmol/L for melatonin, cortisol, and testosterone, respectively. The developed method was sensitive enough to measure circadian rhythms of all 3 hormones in a pilot study among four healthy volunteers. It can therefor be used to study the impact of night work and working in artificial light on the workers circadian rhythms. To our knowledge this is the first LC-ESI-MS/MS method for simultaneous determination of salivary melatonin, cortisol and testosterone. Copyright © 2011 Elsevier B.V. All rights reserved.

  3. Simultaneous Determination of Cyclosporine A, Tacrolimus, Sirolimus, and Everolimus in Whole-Blood Samples by LC-MS/MS

    Directory of Open Access Journals (Sweden)

    Mustafa Karapirli

    2012-01-01

    Full Text Available Objectives. Cyclosporine A (CyA, tacrolimus (TRL, sirolimus (SIR, and everolimus (RAD are immunosuppressive drugs frequently used in organ transplantation. Our aim was to confirm a robust sensitive and selective liquid chromatography-tandem mass spectrometry (LC-MS/MS method for determination of CyA, TRL, SIR, and RAD in whole-blood samples. Materials and Methods. We used an integrated online solid-phase extraction-LC-MS/MS system and atmospheric pressure ionization tandem mass spectrometry (API-MS/MS in the multiple reaction monitoring (MRM detection mode. CyA, TRL, SIR, and RAD were simultaneously analyzed in whole blood treated with precipitation reagent taken from transplant patients. Results. System performance parameters were suitable for using this method as a high-throughput technique in clinical practice. The high concentration of one analyte in the sample did not affect the concentration of other analytes. Total analytical time was 2.5 min, and retention times of all analytes were shorter than 2 minutes. Conclusion. This LC-MS/MS method can be preferable for therapeutic drug monitoring of these immunosuppressive drugs (CyA, TRL, SRL, and RAD in whole blood. Sample preparation was too short and simple in this method, and it permits robust, rapid, sensitive, selective, and simultaneous determination of these drugs.

  4. Graphitic carbon nitride nanosheets doped graphene oxide for electrochemical simultaneous determination of ascorbic acid, dopamine and uric acid

    International Nuclear Information System (INIS)

    Zhang, Hanqiang; Huang, Qitong; Huang, Yihong; Li, Feiming; Zhang, Wuxiang; Wei, Chan; Chen, Jianhua; Dai, Pingwang; Huang, Lizhang; Huang, Zhouyi; Kang, Lianping; Hu, Shirong; Hao, Aiyou

    2014-01-01

    Graphical abstract: Schematic drawing of electrochemical oxidize AA, DA and UA on graphitic carbon nitride nanosheets-graphene oxide composite modified electrode. - Highlights: • Synthesize g-C 3 N 4 , GO and CNNS-GO composite. • CNNS-GO composite was the first time for simultaneous determination of AA, DA and UA. • CNNS-GO/GCE displays fantastic selectivity and sensitivity for AA, DA and UA. • CNNS-GO/GCE was applied to detect real sample with satisfactory results. - Abstract: Graphitic carbon nitride nanosheets with a graphite-like structure have strong covalent bonds between carbon and nitride atoms, and nitrogen atoms in the carbon architecture can accelerate the electron transfer and enhance electrical properties effectually. The graphitic carbon nitride nanosheets-graphene oxide composite was synthesized. And the electrochemical performance of the composite was investigated by cyclic voltammetry and differential pulse voltammetry ulteriorly. Due to the synergistic effects of layer-by-layer structures by π-π stacking or charge-transfer interactions, graphitic carbon nitride nanosheets-graphene oxide composite can improved conductivity, electro-catalytic and selective oxidation performance. The proposed graphitic carbon nitride nanosheets-graphene oxide composite modified electrode was employed for simultaneous determination of ascorbic acid, dopamine and uric acid in their mixture solution, it exhibited distinguished sensitivity, wide linear range and low detection limit. Moreover, the modified electrode was applied to detect urine and dopamine injection sample, and then the samples were spiked with certain concentration of three substances with satisfactory recovery results

  5. Simultaneous determination of size and refractive index of red blood cells by light scattering measurements

    International Nuclear Information System (INIS)

    Ghosh, N.; Buddhiwant, P.; Uppal, A.; Majumder, S.K.; Patel, H.S.; Gupta, P.K.

    2006-01-01

    We present a fast and accurate approach for simultaneous determination of both the mean diameter and refractive index of a collection of red blood cells (RBCs). The approach uses the peak frequency of the power spectrum and the corresponding phase angle obtained by performing Fourier transform on the measured angular distribution of scattered light to determine these parameters. Results on the measurement of two important clinical parameters, the mean cell volume and mean cell hemoglobin concentration of a collection of RBCs, are presented

  6. Simultaneous HPTLC determination of strychnine and brucine in strychnos nux-vomica seed

    Directory of Open Access Journals (Sweden)

    Abid Kamal

    2012-01-01

    Full Text Available Objective: A simple, sensitive, and specific thin layer chromatography (TLC densitometry method has been developed for the simultaneous quantification of strychnine and brucine in the seeds of Strychnos nux-vomica. Materials and Methods: The method involved simultaneous estimation of strychnine and brucine after resolving it by high performance TLC (HPTLC on silica gel plate with chloroform-methanol-formic acid (8.5:1.5:0.4 v/v/v as the mobile phase. Results: The method was validated as per the ICH guidelines for precision (interday, intraday, intersystem, robustness, accuracy, limit of detection, and limit of quantitation. The relationship between the concentration of standard solutions and the peak response was linear within the concentration range of 50-1000 ng/spot for strychnine and 100-1000 ng/spot for brucine. The method precision was found to be 0.58-2.47 (% relative standard deviation [RSD] and 0.36-2.22 (% RSD for strychnine and brucine, respectively. Accuracy of the method was checked by recovery studies conducted at three different concentration levels and the average percentage recovery was found to be 100.75% for strychnine and 100.52% for brucine, respectively. Conclusions: The HPTLC method for the simultaneous quantification of strychnine and brucine was found to be simple, precise, specific, sensitive, and accurate and can be used for routine analysis and quality control of raw material of S. nux-vomica and several unani and ayurvedic formulations containing this as an ingredient.

  7. Sensitive simultaneous detection of seven sexually transmitted agents in semen by multiplex-PCR and of HPV by single PCR.

    Directory of Open Access Journals (Sweden)

    Fabrícia Gimenes

    Full Text Available Sexually transmitted diseases (STDs may impair sperm parameters and functions thereby promoting male infertility. To date limited molecular studies were conducted to evaluate the frequency and type of such infections in semen Thus, we aimed at conceiving and validating a multiplex PCR (M-PCR assay for the simultaneous detection of the following STD pathogens in semen: Chlamydia trachomatis, Neisseria gonorrhoeae, Mycoplasma genitalium, Trichomonas vaginalis, Herpes virus simplex (HSV -1 and -2, and Treponema pallidum; We also investigated the potential usefulness of this M-PCR assay in screening programs for semen pathogens. In addition, we aimed: to detect human Papillomavirus (HPV and genotypes by single PCR (sPCR in the same semen samples; to determine the prevalence of the seven STDs, HPV and co-infections; to assess the possibility that these infections affect semen parameters and thus fertility. The overall validation parameters of M-PCR were extremely high including agreement (99.2%, sensitivity (100.00%, specificity (99.70%, positive (96.40% and negative predictive values (100.00% and accuracy (99.80%. The prevalence of STDs was very high (55.3%. Furthermore, associations were observed between STDs and changes in semen parameters, highlighting the importance of STD detection in semen. Thus, this M-PCR assay has great potential for application in semen screening programs for pathogens in infertility and STD clinics and in sperm banks.

  8. Patients Taking Amoxicillin-Clavulanic Can Become Simultaneously Sensitized to Both Drugs.

    Science.gov (United States)

    Salas, María; Laguna, Jose Julio; Doña, Inmaculada; Barrionuevo, Esther; Fernandez-Santamaría, Rubén; Ariza, Adriana; Perez-Inestrosa, Ezequiel; Mayorga, Cristobalina; Fernández, Tahia Diana; Torres, María José

    Patients can react to amoxicillin (AX) and clavulanic acid (CLV) taken in combination because of selective reactions to either drug. However, scant information exists concerning patients who react simultaneously to both compounds. To analyze the mechanisms involved in 4 patients who developed allergic reactions to AX-CLV administration (3 with immediate IgE-mediated reaction and 1 with nonimmediate T-cell-mediated reaction) and who responded specifically to both AX and CLV. Skin tests with benzylpenicillin (BP), AX, and CLV were done and, if necessary, drug provocation tests with BP/penicillin V, AX, and AX-CLV were carried out. In immediate reactors, serum specific IgE to benzylpenicilloyl and amoxicilloyl was determined by using the CAP-FEIA system (Pharmacia Diagnostics, Uppsala, Sweden), and basophil activation test to BP, AX, CLV, and AX-CLV was done. In nonimmediate reactors, immunohistochemistry of skin biopsy and analysis of dendritic cell maturation and T-cell-specific response to BP, AX, CLV, and AX-CLV at both acute and resolution phases of the reaction were conducted. All patients with immediate reactions (N = 3) had good tolerance to BP and penicillin V. Two cases also had specific IgE to AX and all had a basophil activation test positive to AX, CLV, and AX-CLV. The patient with a nonimmediate reaction exhibited dendritic cell and T-lymphocyte responses specific to both AX and CLV. Finally, the analysis of the cells infiltrating the skin and peripheral blood during the acute phase indicated a T H 1 pattern response. Our study provides evidence that reactions to both AX and CLV can appear in the same patient. Copyright © 2017 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.

  9. Dual enzymatic biosensor for simultaneous amperometric determination of histamine and putrescine.

    Science.gov (United States)

    Henao-Escobar, W; Del Torno-de Román, L; Domínguez-Renedo, O; Alonso-Lomillo, M A; Arcos-Martínez, M J

    2016-01-01

    A disposable electrodic system consisting of two working electrodes connected in array mode has been developed for the simultaneous determination of histamine (His) and putrescine (Put). Histamine deshydrogenase and putrescine oxidase enzymes were respectively immobilized by crosslinking on each working screen-printed electrode, both modified with tetrathiafulvalene. The dual system allowed the simultaneous amperometric determination of both species by measuring the oxidation current of the mediator in each working electrode. The effect of other potentially interfering biogenic amines was also evaluated. The capability of detection was of 8.1 ± 0.7 for His and 10 ± 0.6 μM for Put. The precision in terms of relative standard deviation was of 3.5% and 6.7% for His and Put, respectively. The developed biosensor was successfully applied to the determination of His and Put in different food samples. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. Simultaneous spectrophotometric determination of synthetic dyes in food samples after cloud point extraction using multiple response optimizations.

    Science.gov (United States)

    Heidarizadi, Elham; Tabaraki, Reza

    2016-01-01

    A sensitive cloud point extraction method for simultaneous determination of trace amounts of sunset yellow (SY), allura red (AR) and brilliant blue (BB) by spectrophotometry was developed. Experimental parameters such as Triton X-100 concentration, KCl concentration and initial pH on extraction efficiency of dyes were optimized using response surface methodology (RSM) with a Doehlert design. Experimental data were evaluated by applying RSM integrating a desirability function approach. The optimum condition for extraction efficiency of SY, AR and BB simultaneously were: Triton X-100 concentration 0.0635 mol L(-1), KCl concentration 0.11 mol L(-1) and pH 4 with maximum overall desirability D of 0.95. Correspondingly, the maximum extraction efficiency of SY, AR and BB were 100%, 92.23% and 95.69%, respectively. At optimal conditions, extraction efficiencies were 99.8%, 92.48% and 95.96% for SY, AR and BB, respectively. These values were only 0.2%, 0.25% and 0.27% different from the predicted values, suggesting that the desirability function approach with RSM was a useful technique for simultaneously dye extraction. Linear calibration curves were obtained in the range of 0.02-4 for SY, 0.025-2.5 for AR and 0.02-4 μg mL(-1) for BB under optimum condition. Detection limit based on three times the standard deviation of the blank (3Sb) was 0.009, 0.01 and 0.007 μg mL(-1) (n=10) for SY, AR and BB, respectively. The method was successfully used for the simultaneous determination of the dyes in different food samples. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. Simultaneous determination of ascorbic acid, dopamine and uric acid using high-performance screen-printed graphene electrode.

    Science.gov (United States)

    Ping, Jianfeng; Wu, Jian; Wang, Yixian; Ying, Yibin

    2012-04-15

    A disposable and sensitive screen-printed electrode using an ink containing graphene was developed. This electrode combined the advantages of graphene and the disposable characteristic of electrode, which possessed wide potential window, low background current and fast electron transfer kinetics. Compared with the electrodes made from other inks, screen-printed graphene electrode (SPGNE) showed excellent electrocatalytic activity for the oxidation of ascorbic acid (AA), dopamine (DA), and uric acid (UA). Three well-defined sharp and fully resolved anodic peaks were found at the developed electrode. Differential pulse voltammetry was used to simultaneous determination of AA, DA, and UA in their ternary mixture. In the co-existence system of these three species, the linear response ranges for the determination of AA, DA, and UA were 4.0-4500 μM, 0.5-2000 μM, and 0.8-2500 μM, respectively. The detection limits (S/N=3) were found to be 0.95 μM, 0.12 μM, and 0.20 μM for the determination of AA, DA, and UA, respectively. Furthermore, the SPGNE displayed high reproducibility and stability for these species determination. The feasibility of the developed electrode for real sample analysis was investigated. Results showed that the SPGNE could be used as a sensitive and selective sensor for simultaneous determination of AA, DA, and UA in biological samples, which may provide a promising alternative in routine sensing applications. Copyright © 2012 Elsevier B.V. All rights reserved.

  12. A comparison of simultaneous plasma, atomic absorption, and iron colorimetric determinations of major and trace constituents in acid mine waters

    Science.gov (United States)

    Ball, J.W.; Nordstrom, D. Kirk

    1994-01-01

    Sixty-three water samples collected during June to October 1982 from the Leviathan/Bryant Creek drainage basin were originally analyzed by simultaneous multielement direct-current plasma (DCP) atomic-emission spectrometry, flame atomic-absorption spectrometry, graphite-furnace atomic-absorption spectrometry (GFAAS) (thallium only), ultraviolet-visible spectrometry, and hydride-generation atomic-absorption spectrometry.Determinations were made for the following metallic and semi-metallic constituents: AI, As, B, Ba, Be, Bi, Cd, Ca, Cr, Co, Cu, Fe(11), Fe(total), Li, Pb, Mg, Mn, Mo, Ni, K, Sb, Se, Si, Na, Sr, TI, V, and Zn. These samples were re-analyzed later by simultaneous multielement inductively coupled plasma (ICP) atomic-emission spectrometry and Zeeman-corrected GFAAS to determine the concentrations of many of the same constituents with improved accuracy, precision, and sensitivity. The result of this analysis has been the generation of comparative concentration values for a significant subset of the solute constituents. Many of the more recently determined values replace less-than-detection values for the trace metals; others constitute duplicate analyses for the major constituents. The multiple determinations have yielded a more complete, accurate, and precise set of analytical data. They also have resulted in an opportunity to compare the performance of the plasma-emission instruments operated in their respective simultaneous multielement modes. Flame atomic-absorption spectrometry was judged best for Na and K and hydride-generation atomic-absorption spectrometry was judged best for As because of their lower detection limit and relative freedom from interelement spectral effects. Colorimetric determination using ferrozine as the color agent was judged most accurate, precise, and sensitive for Fe. Cadmium, lead, and vanadium concentrations were too low in this set of samples to enable a determination of whether ICP or DCP is a more suitable technique. Of

  13. A simple electroanalytical methodology for the simultaneous determination of dopamine, serotonin and ascorbic acid using an unmodified edge plane pyrolytic graphite electrode.

    Science.gov (United States)

    Kachoosangi, Roohollah Torabi; Compton, Richard G

    2007-04-01

    A simple method using an unmodified edge plane pyrolytic graphite electrode (EPPGE) is reported for the simultaneous determination of dopamine (DA), serotonin (ST) and ascorbic acid (AA). The performance of this electrode is superior to other unmodified carbon-based electrodes and also to many modified electrodes in terms of detection limit, sensitivity and peak separation for determination of DA, ST and AA. Using this method, detection limits of 90 nM, 60 nM and 200 nM were obtained for DA, ST and AA respectively. No electrode fouling is observed during a set of experiments and good sensitivity is obtained for the simultaneous determination of DA, ST and AA. The peaks for the three species are well resolved from each other and the electrode is successfully utilised for their determination in standard and real samples.

  14. Development of RP-HPLC method for simultaneous determination of docetaxel and curcumin in rat plasma: Validation and stability

    Directory of Open Access Journals (Sweden)

    Dong Wuk Kim

    2017-01-01

    Full Text Available The purpose of the present research was to develop a suitable, simple, precise, accurate, robust, and reproducible RP-HPLC method for a reliable simultaneous quantification of docetaxel (DTX and curcumin (CCM in rat plasma samples using paclitaxel (PTX as an internal standard. The samples were assayed by the Agilent 1260 Infinity HPLC instrument using a Capcell Pak C8 column (4.6 mm × 150 mm, 5 µm under isocratic conditions. The mobile phase consisted of acetonitrile and triple distilled water (40/60, v/v with a flow rate of 1.0 ml/min. The eluent was monitored at 230 nm for simultaneous measurement of curcumin and docetaxel. The method was validated by determining system suitability, selectivity, sensitivity, linearity, inter-day and intra-day precision, accuracy, robustness, and stability in accordance with the guidelines of the United States Food and Drug Administration (FDA. The developed chromatographic method proved to be simple, precise, accurate, robust and reproducible. Moreover, the samples showed stability at room temperature over a period of 48 h. Thus, this method would be employed for routine simultaneous quantification of docetaxel and curcumin in rat plasma samples.

  15. A sensitive whole-cell biosensor for the simultaneous detection of a broad-spectrum of toxic heavy metal ions.

    Science.gov (United States)

    Cerminati, S; Soncini, F C; Checa, S K

    2015-04-07

    Bacterial biosensors are simple, cost-effective and efficient analytical tools for detecting bioavailable heavy metals in the environment. This work presents the design, construction and calibration of a novel whole-cell fluorescent biosensory device that, simultaneously and with high sensitivity, reports the presence of toxic mercury, lead, cadmium and/or gold ions in aqueous samples. This bio-reporter can be easily applied as an immediate alerting tool for detecting the presence of harmful pollutants in drinking water.

  16. Radioactivation method for simultaneous determination of nitrogen, phosphorus and potassium content in plants and fertilizers

    International Nuclear Information System (INIS)

    Srapeniants, R.A.; Saveliev, I.B.; Kovtun, J.L.; Sidorov, A.V.; Tsagolov, K.S.; Miroshnikova, N.N.

    1982-01-01

    A radioactivation method for the simultaneous determination of the nitrogen, phosphorus and potassium content in plants and fertilizers is described. Samples to be analyzed and standard samples are exposed to neutron irradiation, and the spectra of gamma radiation induced in the samples are recorded. The samples laid aside for a period of time determined by the half-life of interfering isotopes, and the spectra of the samples and standards are recorded again. The first and second spectra are superposed and shifted relative to each other along the energy axis, and the content of the elements being analyzed is determined by comparing the spectra of the samples and standards

  17. Simultaneous determination of electroactive and non-electroactive food preservatives by novel capillary electrophoresis with amperometric detection.

    Science.gov (United States)

    Wang, Weiyu; Wang, Yiping; Zhang, Junbo; Chu, Qingcui; Ye, Jiannong

    2010-09-23

    A novel capillary electrophoresis and amperometric detection method was achieved by adding an electroactive additive (3,4-dihydroxybenzylamine, 3,4-DHBA) to the running buffer, so that both electroactive and non-electroactive food preservatives were simultaneously determined. Under the selected optimum conditions, four electroactive preservatives (methylparaben, ethylparaben, propylparaben and butylparaben) and two non-electroactive preservatives (potassium sorbate and sodium lactate) were well separated and sensitively detected with detection limits (S/N=3) ranging from 1.06×10(-8) to 2.73×10(-6) g mL(-1). This method has been successfully employed for the determination of both electroactive and non-electroactive preservatives in several food commodities. Copyright © 2010 Elsevier B.V. All rights reserved.

  18. Simultaneous determination of aflatoxin M1, ochratoxin A, zearalenone and α-zearalenol in milk by UHPLC-MS/MS.

    Science.gov (United States)

    Huang, L C; Zheng, N; Zheng, B Q; Wen, F; Cheng, J B; Han, R W; Xu, X M; Li, S L; Wang, J Q

    2014-03-01

    In this study, a sensitive and rapid method has been developed for the simultaneous determination of aflatoxin M1, ochratoxin A, zearalenone and α-zearalenol in milk by ultra high performance liquid chromatography combined with electrospray ionisation triple quadrupole tandem mass spectrometry (UHPLC-ESI-MS/MS). The milk samples were purified using Oasis HLB cartridge. The matrix effects were evaluated by determining the signal suppression-enhancement (SSE) and corrected by external matrix-matched calibration. The limits of quantity (LOQ) of the mycotoxins were in the range of 0.003-0.015μgkg(-1). The high correlation coefficients (R(2)⩾0.996) were obtained in the range of 0.01-1.00μgkg(-1) of the mycotoxins, along with good recovery (87.0-109%), repeatability (3.4-9.9%) and intra-laboratory reproducibility (4.0-9.9%) at the concentrations of 0.025, 0.1 and 0.5μgkg(-1). The detected rates of the mycotoxins were from 16.7% to 96.7% in raw milk, liquid milk and milk powder samples collected from the dairy farms and supermarkets in Beijing. The method proposed is suitable for the simultaneous determination of aflatoxin M1, ochratoxin A, zearalenone, and α-zearalenol, and could be performed for analysing the mycotoxins in milk. Copyright © 2013 Elsevier Ltd. All rights reserved.

  19. Simultaneous determination of nitrogen and phosphorus in cereals using 14 MeV Neutron Activation Analysis

    International Nuclear Information System (INIS)

    Bejarano, R.

    1992-01-01

    A method using 14 MeV neutron activation analysis was developed form non-destructive simultaneous determination of N and P in cereals. The samples were irradiated 5 min. after 0,5 min. decay time. The induced activities were measured using gamma spectrometry with Nal(Tl) well type detector. The accuracy, precision and detection limits obtained are discussed as well as the analytical results for different types of cereals. (Author) 10 refs., 8 tab., 1 fig

  20. Simultaneous Determination of Caffeine and Chlorogenic Acids in Green Coffee by UV/Vis Spectroscopy

    OpenAIRE

    Navarra, G.; Moschetti, M.; Guarrasi, V.; Mangione, M.; Militello, V.; Leone, M.

    2017-01-01

    A simple method for the simultaneous determination of caffeine and chlorogenic acids content in green coffee was reported. The method was based on the use of UV/Vis absorption. It is relevant that the quantification of both caffeine and chlorogenic acids was performed without their preliminary chemical separation despite their spectral overlap in the range 250–350 nm. Green coffee was extracted with 70% ethanol aqueous solution; then the solution was analyzed by spectroscopy. Quantitative det...

  1. Improved voltammetric method for simultaneous determination of Pt and Rh using second derivative signal transformation - application to environmental samples.

    Science.gov (United States)

    Monteiro, Carlos E; Cobelo-Garcia, Antonio; Caetano, Miguel; Correia Dos Santos, Margarida M

    2017-12-01

    The determination of Platinum-group elements (PGE) in relevant environmental matrices is a challenging task. Sensitive and accurate analytical procedures for simultaneous determination of Pt and Rh are still needed. In this study, we report for the first time on the use of second derivative signal transformation to the ultra-trace simultaneous determination of Pt and Rh by Adsorptive Cathodic Stripping Voltammetry (AdCSV). With that step, the ill-defined peaks typically observed in the original voltammograms are transformed into well-shaped peaks, resulting in accurate detection. The experimental conditions were investigated and optimised: a suitable electrolyte for both elements, with less reagents consumption, (0.25M H 2 SO 4 , 0.05M HCl, 0.01M FA and 0.5mM HZ), deposition time (t d ) and deposition potential (E d ). For t d = 120s and E d = -0.75V, linear relationships r > 0.999 were obtained in the concentration range up to 5.8ngL -1 (27 pM) for Pt and up to 3.4ngL -1 (34 pM) for Rh. Limits of detection were 0.2ngL -1 for Pt and 0.08ngL -1 for Rh. Lower values can be achieved by increasing the deposition time. Limits of quantification, LOQ, calculated as 3 times LOD, were 0.5ngL -1 for Pt and 0.2ngL -1 for Rh. The sensitivity of Pt was affected by elevated Zn concentrations, whereas a minor effect was observed for Rh. However, Pt and Rh determinations were not influenced using the standard addition method. Precision as intermediate precision and expressed as relative standard deviation, based on Pt and Rh spiked solutions and digested road dust CRM BCR-723 was 17% and 20% for Pt and Rh, respectively. Recoveries of CRM were around 90% for both elements. The method was successfully applied in the simultaneous determination of Pt and Rh in sediments from Tagus estuary and, for the first time, dissolved Rh was determined in water samples of a waste water treatment plant. Application of this technique in a multidisciplinary approach will be a relevant contribution

  2. Simultaneous determination of hydroquinone and catechol at gold nanoparticles mesoporous silica modified carbon paste electrode

    Energy Technology Data Exchange (ETDEWEB)

    Tashkhourian, J., E-mail: tashkhourian@susc.ac.ir [Department of Chemistry, College of Sciences, Shiraz University, Shiraz 71456 (Iran, Islamic Republic of); Daneshi, M.; Nami-Ana, F. [Department of Chemistry, College of Sciences, Shiraz University, Shiraz 71456 (Iran, Islamic Republic of); Behbahani, M.; Bagheri, A. [Department of Chemistry, Shahid Beheshti University, G.C., Evin, Tehran (Iran, Islamic Republic of)

    2016-11-15

    Highlights: • An electrochemical sensor based on gold nanoparticles mesoporous silica modified carbon paste electrode was developed. • The electrode provides an accessible surface for simultaneous determination of hydroquinone and catechol. • Hydroquinone and catechol are highly toxic to both environment and human even at very low concentrations. - Abstract: A new electrochemical sensor based on gold nanoparticles mesoporous silica modified carbon paste electrode (AuNPs-MPS) was developed for simultaneous determination of hydroquinone and catechol. Morphology and structure of the AuNPs-MPS were characterized by transmission electron microscopy, X-ray diffraction and Fourier transform infrared spectroscopy. The electrochemical behavior of hydroquinone and catechol were investigated using square wave voltammetry and the results indicate that the electrochemical responses are improved significantly at the modified electrode. The observed oxidative peaks separation of about 120 mV made possible the simultaneous determination of hydroquinone and catechol in their binary-mixture. Under the optimized condition, a linear dynamic range of 10.0 μM–1.0 mM range for hydroquinone with the detection limit of 1.2 μM and from 30.0 μM–1.0 mM for catechol with the detection limit of 1.1 μM were obtained. The applicability of the method was demonstrated by the recovery studies of hydroquinone and catechol in spiked tap water samples.

  3. Simultaneous determination of cadaverine and putrescine using a disposable monoamine oxidase based biosensor.

    Science.gov (United States)

    Henao-Escobar, Wilder; Domínguez-Renedo, Olga; Asunción Alonso-Lomillo, M; Julia Arcos-Martínez, M

    2013-12-15

    The selective and simultaneous amperometric determination of putrescine (Put) and cadaverine (Cad) has been carried out using a novel design of screen-printed carbon electrode (SPCE) with two working electrodes connected in array mode. A mixture of 3% of tetrathiafulvalene (TTF), as mediator, and carbon ink was used for the construction of the screen-printed working electrode. The employment of different amounts of monoamine oxidase (MAO) enzyme on these modified TTF/SPCEs and the use of gold nanoparticles (AuNPs) allowed performing the simultaneous determination of both analytes. The amperometric detection has been performed by measuring the oxidation current of the mediator at a potential of+250 mV vs. screen-printed Ag/AgCl reference electrode. A linear response in the Cad concentration range from 19.6 till 107.1 µM and from 9.9 till 74.1 μM for Put was obtained at the MAO/AuNPs/TTF/SPCE biosensor. This device showed a capability of detection of 9.9 and 19.9±0.9 µM (n=4 α=β=0.05) and a precision of 4.9% and 10.3% in terms of relative standard deviation for Put and Cad, respectively. The developed biosensor was successfully applied to the simultaneous determination of Put and Cad in octopus samples. © 2013 Elsevier B.V. All rights reserved.

  4. Application of different spectrophotometric methods for simultaneous determination of elbasvir and grazoprevir in pharmaceutical preparation

    Science.gov (United States)

    Attia, Khalid A. M.; El-Abasawi, Nasr M.; El-Olemy, Ahmed; Abdelazim, Ahmed H.

    2018-01-01

    The first three UV spectrophotometric methods have been developed of simultaneous determination of two new FDA approved drugs namely; elbasvir and grazoprevir in their combined pharmaceutical dosage form. These methods include simultaneous equation, partial least squares with and without variable selection procedure (genetic algorithm). For simultaneous equation method, the absorbance values at 369 (λmax of elbasvir) and 253 nm (λmax of grazoprevir) have been selected for the formation of two simultaneous equations required for the mathematical processing and quantitative analysis of the studied drugs. Alternatively, the partial least squares with and without variable selection procedure (genetic algorithm) have been applied in the spectra analysis because the synchronous inclusion of many unreal wavelengths rather than by using a single or dual wavelength which greatly increases the precision and predictive ability of the methods. Successfully assay of the drugs in their pharmaceutical formulation has been done by the proposed methods. Statistically comparative analysis for the obtained results with the manufacturing methods has been performed. It is noteworthy to mention that there was no significant difference between the proposed methods and the manufacturing one with respect to the validation parameters.

  5. A sensitive spectrophotometric determination of nitrogen dioxide in ...

    African Journals Online (AJOL)

    In the present investigation, a simple and sensitive spectrophotometric method for the determination of nitrogen dioxide in various environmental samples is described. Nitrogen dioxide in air was fixed as nitrite ion in alkaline sodium arsenite absorbing solution. The nitrite formed was diazotized with paminoacetophenone in ...

  6. Sensitive amperometric determination of hydrazine using a carbon ...

    Indian Academy of Sciences (India)

    Sensitive amperometric determination of hydrazine using a carbon paste electrode modified with silver-doped zeolite L nanoparticles. NEDA SALEK GILANI ... The unique porous structure of nanozeolite L offers a promising catalyst support candidate for efficient electrochemical sensing of hydrazine. The sensor exhibited ...

  7. Sensitivity and specificity of copper sulphate test in determining ...

    African Journals Online (AJOL)

    Background: The accuracy of the copper sulphate method for the rapid screening of prospective blood donors has been questioned because this rapid screening method may lead to false deferral of truly eligible prospective blood donors. Objective: This study was aimed at determining the sensitivity and specificity of copper ...

  8. Enzymatic biosensor of horseradish peroxidase immobilized on Au-Pt nanotube/Au-graphene for the simultaneous determination of antioxidants

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Long; Yin, Wenmin; Tang, Kun; Li, Dian; Shao, Kang; Zuo, Yunpeng; Ma, Jing; Liu, Jiawei; Han, Heyou, E-mail: hyhan@mail.hzau.edu.cn

    2016-08-24

    A new electrochemical method has been proposed for the simultaneous determination of butylated hydroxyanisole (BHA) and propyl gallate (PG) in food matrices based on enzymatic biosensors. Spiny Au-Pt nanotubes (SAP NTs) was first synthesized and demonstrated to exhibit intrinsic peroxidase and catalase-like activity. The structure of SAP NTs provides large surface area and favorable medium for electron transfer, on which HRP were immobilized and acted as enzymatic biosensor for the simultaneous detection of BHA and PG. The results revealed that BHA and PG both have well-defined oxidation waves with peak potentials of 624 and 655 mV, respectively. Under the optimal conditions, the method behaved satisfactory analytical performance towards BHA and PG with a wide linear range of 0.3–50 mg L{sup −1} and 0.1–100 mg L{sup −1}, as well as a detection limit of 0.046 mg L{sup −1} and 0.024 mg L{sup −1} (3σ/slope), respectively. Besides, the proposed method exhibits good sensitivity, stability and reproducibility, providing an alternative to fabricate electrode and construct sensitive biosensors. - Highlights: • SAP NTs was synthesized and demonstrated to exhibit intrinsic peroxidase and catalase-like activity. • The structure of SAP NTs provides larger surface area and more favorable medium for electron transfer. • Horseradish peroxidase immobilized on Au-Pt nanotube/Au-graphene acted as enzymatic biosensor. • The simultaneous detection of BHA and PG in food matrices was achieved based on enzymatic biosensors.

  9. Poly(alizarin red)/Graphene modified glassy carbon electrode for simultaneous determination of purine and pyrimidine

    Energy Technology Data Exchange (ETDEWEB)

    Ba Xi; Luo Liqiang [Department of Chemistry, Shanghai University, Shanghai 200444 (China); Ding Yaping, E-mail: wdingyp@sina.com [Department of Chemistry, Shanghai University, Shanghai 200444 (China); Zhang Zhen [Department of Chemistry, Shanghai University, Shanghai 200444 (China); Chu Yuliang [Instrumental Analysis and Research Center, Shanghai University, Shanghai 200444 (China); Wang Bijun; Ouyang Xiaoqian [Department of Chemistry, Shanghai University, Shanghai 200444 (China)

    2012-11-08

    Graphical abstract: DPVs of PAR/Graphene/GCE (a) and the bare GCE (c) in 0.1 M PBS containing 50.0 {mu}M G, 50.0 {mu}M A, 100.0 {mu}M T and 100.0 {mu}M C, (b) PAR/Graphene/GCE in 0.1 M PBS. Highlights: Black-Right-Pointing-Pointer The sensor exhibited well-separated peaks and low detection limit. Black-Right-Pointing-Pointer The sensor possesses high sensitivity and wide linear range. Black-Right-Pointing-Pointer The sensor was used for simultaneous detection of G, A, T and C successfully. Black-Right-Pointing-Pointer The sensor was applied in a fish sperm DNA sample with satisfactory results. Black-Right-Pointing-Pointer The proposed sensor has good stability and reproducibility. - Abstract: In this work, a poly(alizarin red)/Graphene composite film modified glassy carbon electrode (PAR/Graphene/GCE) was prepared for simultaneous determination of four DNA bases (guanine, adenine, thymine and cytosine) without any pretreatment. The morphology and interface property of PAR/Graphene films were examined by scanning electron microscopy and electrochemical impedance spectroscopy. The PAR/Graphene/GCE exhibited excellent electrocatalytic activity toward purine (guanine and adenine) and pyrimidine (thymine and cytosine) in 0.1 M phosphate buffer solution (pH 7.4). Under optimum conditions, differential pulse voltammetry was used to detect the oxidation of purine and pyrimidine. The results showed that PAR/Graphene/GCE exhibited well-separated peaks, low detection limit, high sensitivity and wide linear range for simultaneous detection of purine and pyrimidine. The proposed sensor also has good stability and reproducibility. Furthermore, the modified electrode was applied for the detection of DNA bases in a fish sperm DNA sample with satisfactory results.

  10. Poly(alizarin red)/Graphene modified glassy carbon electrode for simultaneous determination of purine and pyrimidine

    International Nuclear Information System (INIS)

    Ba Xi; Luo Liqiang; Ding Yaping; Zhang Zhen; Chu Yuliang; Wang Bijun; Ouyang Xiaoqian

    2012-01-01

    Graphical abstract: DPVs of PAR/Graphene/GCE (a) and the bare GCE (c) in 0.1 M PBS containing 50.0 μM G, 50.0 μM A, 100.0 μM T and 100.0 μM C, (b) PAR/Graphene/GCE in 0.1 M PBS. Highlights: ► The sensor exhibited well-separated peaks and low detection limit. ► The sensor possesses high sensitivity and wide linear range. ► The sensor was used for simultaneous detection of G, A, T and C successfully. ► The sensor was applied in a fish sperm DNA sample with satisfactory results. ► The proposed sensor has good stability and reproducibility. - Abstract: In this work, a poly(alizarin red)/Graphene composite film modified glassy carbon electrode (PAR/Graphene/GCE) was prepared for simultaneous determination of four DNA bases (guanine, adenine, thymine and cytosine) without any pretreatment. The morphology and interface property of PAR/Graphene films were examined by scanning electron microscopy and electrochemical impedance spectroscopy. The PAR/Graphene/GCE exhibited excellent electrocatalytic activity toward purine (guanine and adenine) and pyrimidine (thymine and cytosine) in 0.1 M phosphate buffer solution (pH 7.4). Under optimum conditions, differential pulse voltammetry was used to detect the oxidation of purine and pyrimidine. The results showed that PAR/Graphene/GCE exhibited well-separated peaks, low detection limit, high sensitivity and wide linear range for simultaneous detection of purine and pyrimidine. The proposed sensor also has good stability and reproducibility. Furthermore, the modified electrode was applied for the detection of DNA bases in a fish sperm DNA sample with satisfactory results.

  11. Simultaneous determination of chloroamphenicol, thiamphenicol and florfenicol residues in bovine milk by micellar electrokinetic chromatography

    OpenAIRE

    Pezza, Leonardo [UNESP; Ríos, Àngel; Nozal, Leonor; Arce, Lourdes; Valcárce, Miguel

    2006-01-01

    A micellar electrokinetic chromatographic method (MEKC) is described for determining residues of amphenicols(chloramphenicol,thiamphenicol and florfenicol) in bovine milk. MEKC is conducted by using a separation buffer consisting of 20 mM Na2HPO4, 10 mM Na2B4O7, 50 mM SDS at pH 8.0; UV detection at 210 nm and 10 kV of voltage. The limit of detection ranged from 4.3-5.3 µg L-1. The MEKC method was applied for the simultaneous determination of amphenicols in milk samples spiked with amphenicols...

  12. Simultaneous determination of triple therapy for Helicobacter pylori in human plasma by reversed phase chromatography with online wavelength switching

    Science.gov (United States)

    Ahmed, Sameh; Atia, Noha N.

    2015-02-01

    The infection of gastric mucosa by Helicobacter pylori (HP) is an essential cofactor in the aetiology of gastroduodenal ulcer and gastric carcinoma. Because of the bacterial resistance, combination therapy containing omeprazole (OME), tinidazole (TNZ) and clarithromycin (CLA) is commonly used for eradication of HP. However, the simultaneous determination of the triple therapy in human plasma was not reported. A simple, reproducible, and selective HPLC method was developed for the simultaneous determination of the triple therapy mixture used for management of HP infections in human plasma. An HPLC procedure based on a liquid-liquid extraction, enrichment of the analytes and subsequent reversed-phase chromatography with UV detection was used. To enable sensitive and selective detection, the method involved the use of online wavelength switching detection, with two different detection wavelengths; 280 nm for detection of OME and TNZ and 210 nm for detection of CLA. Separations were performed on C18 analytical column with acetonitrile-10 mM phosphate buffer of pH = 3.0 at flow rate of 1.0 mL min-1. The linear ranges in human plasma were 0.05-10 μg mL-1 with correlation coefficients >0.9990. The detection limits in human plasma were 0.02-0.07 μg mL-1. Validation parameters were assessed in compliance with US-FDA guidelines. The method proved to be valuable for the therapeutic drug monitoring after oral administration of triple therapy tablets.

  13. Simultaneous determination of amlodipine besylate and atorvastatin calcium in binary mixture by spectrofluorimetry and HPLC coupled with fluorescence detection.

    Science.gov (United States)

    Moussa, Bahia A; El-Zaher, Asmaa A; Mahrouse, Marianne A; Ahmed, Maha S

    2013-01-01

    Caduet tablets are novel prescription drug that combines amlodipine besylate (AM) with atorvastatin calcium (AT). A spectrofluorimetric and an HPLC-fluorescence detection methods were developed for simultaneous determination of both drugs in tablets. In the spectrofluorimetric method, native fluorescence of AM and AT were measured in methanol at 442 and 369 nm upon excitation at 361 and 274 nm, respectively. The emission spectrum of each drug reveals zero value at the emission wavelength of the other drug, thus allowing their simultaneous determination without interference. In the HPLC method, separation of AM and AT was achieved within 8 minutes on a C18 column using acetonitrile:phosphate buffer (0.015 M, pH 3) (45:55, v/v) as the mobile phase. Fluorescence detection was carried out using excitation wavelengths 361 and 274 nm and emission wavelengths 442 and 378 nm for AM and AT, respectively. Excellent linearity was observed. Careful validation proved advantages of the new methods: high sensitivity, accuracy, selectivity and suitability for quality control laboratories.

  14. Simultaneous DPV determination of morphine and codeine using dsDNA modified screen printed electrode strips coupled with electromembrane extraction

    Directory of Open Access Journals (Sweden)

    Rouhollah Feizbakhsh

    2016-01-01

    Full Text Available In this work a sensitive electrochemical sensor for simultaneous determination of morphine and codeine constructed by application of disposable screen printed carbon electrode strips (SPCE modified by double strand (ds calf thymus DNA. According to the results of the modified SPCE strips and experimented parameters, we observed a considerable shift between potentials of morphine and codeine current peaks. Related to these observed shifts, we studied on the effect of the concentration of modifier and pH value on the anodic oxidation pattern of morphine and codeine in the case of optimize the method to get better signals with maximum potential distance. Also to boosting the LODs of this electroanalytical method coupled with an electro-membrane preconcentration (EME step. The calibration curve which was plotted by the variation of differential pulse voltammetry (DPV currents as a function of different morphine and codeine concentration were linear within the range of 0.7– 40 µM and 2.3- 40 µM for morphine and codeine respectively. Also the limits of detection were 0.07 µM and 0.23 µM, respectively. Finally, the proposed method was able to determine morphine and codeine simultaneously and effectively in urinary real samples

  15. Process monitored spectrophotometric titration coupled with chemometrics for simultaneous determination of mixtures of weak acids.

    Science.gov (United States)

    Liao, Lifu; Yang, Jing; Yuan, Jintao

    2007-05-15

    A new spectrophotometric titration method coupled with chemometrics for the simultaneous determination of mixtures of weak acids has been developed. In this method, the titrant is a mixture of sodium hydroxide and an acid-base indicator, and the indicator is used to monitor the titration process. In a process of titration, both the added volume of titrant and the solution acidity at each titration point can be obtained simultaneously from an absorption spectrum by least square algorithm, and then the concentration of each component in the mixture can be obtained from the titration curves by principal component regression. The method only needs the information of absorbance spectra to obtain the analytical results, and is free of volumetric measurements. The analyses are independent of titration end point and do not need the accurate values of dissociation constants of the indicator and the acids. The method has been applied to the simultaneous determination of the mixtures of benzoic acid and salicylic acid, and the mixtures of phenol, o-chlorophenol and p-chlorophenol with satisfactory results.

  16. Simultaneous in-line concentration for spectrophotometric determination of cations and anions

    Directory of Open Access Journals (Sweden)

    Rocha Fábio R. P

    2004-01-01

    Full Text Available A flow system is proposed for simultaneous in-line concentration of cations and anions. A sliding-bar commutator was employed to insert an anion and a cation exchange column into a flowing sample stream for serial retention of the analytes. In the injector alternative position, different solutions flowed through the columns for parallel elution of the species in different analytical paths. Three-way solenoid valves allowed the intermittent reagent introduction in the sample zones. Signals were measured by employing two flow-through LED-based detectors. The simultaneous retention of the sample zones in coiled reactors can be also performed to increase the residence time and the analyte conversion rate. The analytical potentiality was demonstrated by the in-line concentration of ammonium and phosphate followed by spectrophotometric detection. For a 90 s loading time, the sampling rate was estimated as 40 determinations per hour, which is three-fold higher than the obtained without performing the tasks simultaneously. Enrichment factors of 8.0 and 18 were estimated for phosphate and ammonium, respectively, yielding detection limits of 1 mg L-1 PO4(3- and 1 mg L-1 NH4+ (99.7% confidence level. The reagent consumption was lower than 2 mg per determination. Results for freshwater samples agreed with the obtained by reference APHA procedures at the 95% confidence level.

  17. Simultaneous Absorptance and Thermal-Diffusivity Determination of Optical Components with Laser Calorimetry Technique

    Science.gov (United States)

    Wang, Yanru; Li, Bincheng

    2012-11-01

    The laser calorimetry (LCA) technique is used to determine simultaneously the absorptances and thermal diffusivities of optical components. An accurate temperature model, in which both the finite thermal conductivity and the finite sample size are taken into account, is employed to fit the experimental temperature data measured with an LCA apparatus for a precise determination of the absorptance and thermal diffusivity via a multiparameter fitting procedure. The uniqueness issue of the multiparameter fitting is discussed in detail. Experimentally, highly reflective (HR) samples prepared with electron-beam evaporation on different substrates (BK7, fused silica, and Ge) are measured with LCA. For the HR-coated sample on a fused silica substrate, the absorptance is determined to be 15.4 ppm, which is close to the value of 17.6 ppm, determined with a simplified temperature model recommended in the international standard ISO11551. The thermal diffusivity is simultaneously determined via multiparameter fitting to be approximately 6.63 × 10-7 m2 · s-1 with a corresponding square variance of 4.8 × 10-4. The fitted thermal diffusivity is in reasonably good agreement with the literature value (7.5 × 10-7 m2 · s -1). Good agreement is also obtained for samples with BK7 and Ge substrates.

  18. Simultaneous determination of butyltin and phenyltin species in sediments using ultrasound-assisted leaching

    Energy Technology Data Exchange (ETDEWEB)

    Carpinteiro, J.; Rodriguez, I.; Cela, R. [Dpto. Quimica Analitica, Nutricion y Bromatologia, Universidad de Santiago de Compostela (Spain)

    2001-08-01

    A fast and simple procedure is presented for the simultaneous leaching of butyl (mono, di and tributyl) and phenyl organotin species from sediment samples. Leached compounds are further ethylated with sodium tetraethylborate in aqueous medium, and analyzed by gas chromatography. After testing the stability of triphenyltin under different extraction conditions, ultrasound-assisted leaching at room temperature in the presence of acetic acid was been proposed as an extraction procedure compatible with the simultaneous determination of phenyl- and butyltin compounds in sediments. Recoveries between 70 and 90% were obtained for phenyl species in spiked samples prepared in the laboratory. Results for butyltin species were validated by use of the reference material PACS-2. Quantification limits, using GC-MIP-AES as measurement technique, were approximately 5-10 ng g{sup -1}. Precision in the consecutive analysis of three sediment samples varied between 3 and 10%. (orig.)

  19. Simultaneous Determination of Cobalt (II and Nickel (II By First Order Derivative Spectrophotometry in Micellar Media

    Directory of Open Access Journals (Sweden)

    Rajni Rohilla

    2012-01-01

    Full Text Available A first-derivative spectrophotometry method for the simultaneous determination of Co (II and Ni (II with Alizarin Red S in presence of Triton X-100 is described. Measurements were made at the zero-crossing wavelengths at 549.0 nm for Co (II and 546.0 nm for Ni (II. The linearity is obtained in the range of 0.291- 4.676 μg/ml of Ni (II and 0.293- 4.124 μg/ml of Co (II in the presence of each other by using first derivative spectrophotometric method. The possible interfering effects of various ions were studied. The validity of the method was examined by using synthetic mixtures of Co (II and Ni (II. The developed derivative procedure, using the zero crossing technique, has been successfully applied for the simultaneous analysis of Co (II and Ni (II in spiked water samples.

  20. Simultaneous Determination of Tizanidine, Nimesulide, Aceclofenac and Paracetamol in Tablets and Biological Fluids Using Micellar Liquid Chromatography.

    Science.gov (United States)

    Belal, Fathalla; Omar, Mahmoud A; Derayea, Sayed; Hammad, Mohamed A; Zayed, Sahar; Saleh, Safaa F

    2018-03-01

    A simple, sensitive and rapid micellar liquid chromatographic method was developed and validated for simultaneous determination of four drugs, namely, paracetamol (PAR), tizanidine (TZD), aceclofenac (ACF) and nimesulide (NMD). Good chromatographic separation was achieved using Cyano column and micellar mobile phase consisting of 120 mM sodium dodecyl sulfate, 25 mM phosphate buffer and 10% (V/V) butanol. The pH was adjusted to three using phosphoric acid. The total retention time was below 10 min. The analysis was performed at a flow rate of 1 mL/min and a column temperature of 40°C with direct UV detection at 230 nm. Diclofenac sodium was used as the internal standard. The proposed method was validated according to the ICH guidelines and was successfully applied to the analysis of these drugs in their tablet dosage forms with high accuracy. Limits of detection were found to be 0.03, 0.07, 0.033 and 0.11 μg/mL for PAR, ACF, TZD and NMD, respectively. The high sensitivity of developed method permitted its application to the in-vitro determination of the cited drugs in spiked human plasma and urine samples, and the obtained results were satisfactory. However, PAR could not be determined in spiked human urine because its peak overlapped with that of the urine peak.

  1. Simultaneous determination of rhodium and ruthenium by high-resolution continuum source graphite furnace atomic absorption spectrometry

    Science.gov (United States)

    Zambrzycka-Szelewa, Elżbieta; Lulewicz, Marta; Godlewska-Żyłkiewicz, Beata

    2017-07-01

    In the present paper a fast, simple and sensitive analytical method for simultaneous determination of rhodium and ruthenium by high-resolution continuum source graphite furnace atomic absorption spectrometry (HR-CS GFAAS) was developed. Among six pairs of absorption atomic lines of Rh and Ru, which are close enough to enable their simultaneous detection, two pairs were selected for further studies. Best results were obtained for measurements of the resonance line of rhodium at 343.489 nm and the adjacent secondary line of ruthenium at 343.674 nm (23% intensity of this line). For evaluated lines, the absorbance values were obtained using three pixels. The pyrolysis and atomization temperatures were 1200 °C and 2600 °C, respectively. Under these conditions the limits of detection achieved for Rh and Ru were found to be 1.0 μg L- 1 and 1.9 μg L- 1, respectively. The characteristic mass was 12.9 pg for Rh and 71.7 pg for Ru. Repeatability of the results expressed as a relative standard deviation was typically below 6%. The trueness of the method was confirmed by analysis of the certified reference material - platinum ore (SARM 76). The recovery of Rh and Ru from the platinum ore was 93.0 ± 4.6% and 90.1 ± 2.5%, respectively. The method was successfully applied to the direct simultaneous determination of trace amounts of rhodium and ruthenium in spiked river water, road runoff, and municipal sewage. Separation of interfering matrix on cation exchange resin was required before analysis of road dust and tunnel dust (CW-7) by HR-CS GFAAS.

  2. Simultaneous determination of dapsone, monoacetyldapsone and pyrimethamine in whole blood and plasma by high-performance liquid chromatography

    DEFF Research Database (Denmark)

    Lemnge, M M; Rønn, A; Flachs, H

    1993-01-01

    A sensitive, selective and rapid reversed-phase high-performance liquid chromatographic method was developed for the simultaneous analysis of dapsone, monoacetyldapsone and pyrimethamine in human whole blood and plasma. The procedure involved extraction of the compounds and the internal standard...... absorbance was monitored at 286 nm. The limit of determination using a 150-microliters sample was 10 ng/ml (40 nM) for dapsone and pyrimethamine and 8 ng/ml (28 nM) for monoacetyldapsone. Given that only a small amount of blood is required in this method, it could now be applied in studies involving blood...... level monitoring and pharmacokinetics in children on Maloprim (dapsone-pyrimethamine) prophylaxis in malaria endemic areas....

  3. Simultaneous determination of soil density and moisture by gamma ray attenuation from Cs137 and Am241

    International Nuclear Information System (INIS)

    Barros Ferraz, E.S. de.

    1974-09-01

    The method of simultaneous bulk density and soil moisture determination by attenuation of 241 Am and 137 Cs gamma-radiation is introduced and studied with details. Theoretical considerations are made about the attenuation process in the absorbers, the form of solving the problem of two unknowns; the sensitivity of the method; the influences of the resolution time of the electronic counting equipment, and of the compton scattering in the sample. From the methodological point of view studies are made about the influence of the geometry, adjustment of counting system, choice of radiation sources, attenuation coeficients and the manner of obtaining reliable measurements. It is also presented some applications of the method, its use in soil-water movement studies, in soil profile compaction studies, and specially in swelling soils

  4. Simultaneous quantitative determination of cinnamaldehyde and methyl eugenol from stem bark of Cinnamomum zeylanicum Blume using RP-HPLC.

    Science.gov (United States)

    Gursale, Atish; Dighe, Vidya; Parekh, Guarang

    2010-01-01

    A simple, sensitive, and precise reversed-phase high performance liquid chromatographic (HPLC) method has been developed, validated and used for simultaneous quantitative determination of cinnamaldehyde and methyl eugenol from the methanolic extract of dried bark powder of Cinnamomum zeylanicum Blume (family Lauraceae). The ultrasonic extraction method was used for the extraction of these compounds. The reversed-phase HPLC analysis was carried out using a Intersil ODS-3V-C(18) (150 mm x 4.6 mm, 5 microm) column and a mobile phase comprising of methanol-acetonitrile-water in the volume ratio of 35:20:45, delivered at a flow rate of 1.0 cm(3)/min. The detection and quantitation of both the compounds was carried out at 221 nm.

  5. Simultaneous determination of the content of serotonin, dopamine, noradrenaline and adrenaline in pancreatic islets isolated from fed and starved mice

    International Nuclear Information System (INIS)

    Hansen, S.E.; Hedeskov, C.J.

    1977-01-01

    A highly sensitive double isotope method for the simultaneous determination of serotonin, dopamine, noradrenaline and adrenaline has been developed. Advantages and limitations of the method are discussed. The mentioned biogenic amines are all present in isolated pancreatic islet tissue from albino mice in concentrations ranging from approximately 5-30 μmol per kg wet weight (0.8-5 x 10 -3 pmol/ng DNA). A somewhat higher content of these amines, especially dopamine, was found in pancreatic acinar tissue. The hypothesis that the impaired glucose-induced insulin secretion during starvation partly is caused by an increased content of biogenic amines in the pancreatic islets was not supported by our experiments which showed an unchanged islet content of these amines after 48 h starvation. (author)

  6. Limitations on the strain tensor determination by neutron diffraction using a position-sensitive detector

    International Nuclear Information System (INIS)

    Lorentzen, T.; Christoffersen, J.

    1990-01-01

    Diffraction techniques such as neutron diffraction allow strain components to be measured in arbitrarily chosen directions in structural components, and hence complete strain tensors can in principle be calculated from any six measured normal strain components. However, in a newly developed technique, whereby a position-sensitive detector is used for simultaneous measurements of chosen strain components at several points along a line through the specimen, there appear to be some limitations on the choice of strain components for strain tensor determination. This note verifies the nature of these limitations. (author)

  7. Cascaded-cavity Fabry-Perot interferometer for simultaneous measurement of temperature and strain with cross-sensitivity compensation

    Science.gov (United States)

    Tian, Jiajun; Jiao, Yuzhu; Ji, Shaobo; Dong, Xiaolong; Yao, Yong

    2018-04-01

    We propose and demonstrate a fiber sensor for simultaneous temperature and strain measurements. The proposed sensor is implemented by a cascaded-cavity Fabry-Perot (FP) fiber interferometer. The two cascaded FP cavities comprise a micro-air-cavity in a hollow-core tube fiber and a micro-silica-cavity in a standard single-mode fiber. To separate the interference spectrum of each FP cavity, the total spectrum is filtered in the frequency domain through band-pass filters, whose central frequencies were predesigned based on the relationship between the spatial frequency and free spectral range of each FP cavity. The different cross-sectional areas and thermal-optic coefficients of the two FP cavities confer different sensitivities to temperature and strain. Both parameters were measured simultaneously by tracking the wavelength shifts in the filtered interference spectra of the FP cavities. Moreover, the temperature-strain cross-sensitivity was compensated by solving a sensitivity-coefficient matrix equation for the two cavities, using the calibrated temperatures and strains. Other advantages of the proposed sensor are simple fabrication and an all-fiber structure. Owing to these properties, the proposed sensor is potentially applicable to real sensing applications.

  8. Simultaneous compression and encryption for secure real-time secure transmission of sensitive video transmission

    Science.gov (United States)

    Al-Hayani, Nazar; Al-Jawad, Naseer; Jassim, Sabah A.

    2014-05-01

    Video compression and encryption became very essential in a secured real time video transmission. Applying both techniques simultaneously is one of the challenges where the size and the quality are important in multimedia transmission. In this paper we proposed a new technique for video compression and encryption. Both encryption and compression are based on edges extracted from the high frequency sub-bands of wavelet decomposition. The compression algorithm based on hybrid of: discrete wavelet transforms, discrete cosine transform, vector quantization, wavelet based edge detection, and phase sensing. The compression encoding algorithm treats the video reference and non-reference frames in two different ways. The encryption algorithm utilized A5 cipher combined with chaotic logistic map to encrypt the significant parameters and wavelet coefficients. Both algorithms can be applied simultaneously after applying the discrete wavelet transform on each individual frame. Experimental results show that the proposed algorithms have the following features: high compression, acceptable quality, and resistance to the statistical and bruteforce attack with low computational processing.

  9. Simultaneous Spectrophotometric Determination of Copper, Nickel, and Zinc Using 1-(2-Thiazolylazo)-2-Naphthol in the Presence of Triton X-100 Using Chemometric Methods

    International Nuclear Information System (INIS)

    Low, Kah Hin; Zain, Sharifuddin Md; Abas, Mhd. Radzi; Misran, Misni; Mohd, Mustafa Ali

    2009-01-01

    Multivariate models were developed for the simultaneous spectrophotometric determination of copper (II), nickel (II) and zinc (II) in water with 1-(2-thiazolylazo)-2-naphthol as chromogenic reagent in the presence of Triton X-100. To overcome the drawback of spectral interferences, principal component regression (PCR) and partial least square (PLS) multivariate calibration approaches were applied. Performances were validated with several test sets, and their results were then compared. In general, no significant difference in analytical performance between PLS and PCR models. The root mean square error of prediction (RMSEP) using three components for Cu 2+ , Ni 2+ and Zn 2+ were 0.018, 0.010, 0.011 ppm, respectively. Figures of merit such as sensitivity, analytical sensitivity, limit of detection (LOD) were also estimated. High reliability was achieved when the proposed procedure was applied to simultaneous determination of Cu 2+ , Ni 2+ and Zn 2+ in synthetic mixture and tap water

  10. Simultaneous synthesis and assembly of silver nanoparticles to three-demensional superstructures for sensitive surface-enhanced Raman spectroscopy detection.

    Science.gov (United States)

    Yang, Yanqiong; Wang, Wenqin; Chen, Tao; Chen, Zhong-Ren

    2014-12-10

    Construction of superstructures with controllable morphologies from NPs is of great scientific and technological importance. A one-step method for simultaneous synthesis and assembly of Ag NPs to three-dimensional (3D) nanoporous superstructures is demonstrated. By varying the adsorption time of Ag precursors, an array of well-defined Ag superstructures with different morphologies are harvested. A "hot spot"-rich substrate for surface-enhanced Raman spectroscopy is established, which exhibits high sensitivity in trace detection of molecules. It is believed that the presented 3D nanoporous Ag superstructures hold great potential for various uses, such as novel multifunctional sensing and monitoring chips or devices.

  11. Simultaneous polarographic determination of micro amounts of vanadium(V) and molybdenum(VI)

    International Nuclear Information System (INIS)

    Rao, V.S.N.; Rao, S.B.

    1979-01-01

    A simple and sensitive polarographic method has been developed for the determination of micro quantities of vanadium(V) and molybdenum(VI), based on the reduction of bromate, which is catalysed by these metal ions in the presence of 2,4-dihydroxyacetophenone oxime. Interference by various cations and anions has been investigated. (author)

  12. Determinants of long-term outcome in patients undergoing simultaneous resection of synchronous colorectal liver metastases.

    Directory of Open Access Journals (Sweden)

    Qi Lin

    Full Text Available BACKGROUND: It remains unclear which patients can benefit from simultaneous resection of synchronous colorectal liver metastases (SCRLMs. This study aimed to examine the prognostic value of patient- and tumor-related factors in predicting long-term outcomes of patients undergoing simultaneous resection of SCRLMs and to help patients select a suitable therapeutic regimen and proper surveillance. METHODS: Clinicopathological and outcome data of 154 consecutive SCRLM patients who underwent simultaneous resection between July 2003 and July 2013 were collected from our prospectively established SCRLM data and analyzed with univariate and multivariate methods, and the prognostic index (PI was formulated based on the regression coefficients (β of the Cox model. The patients were classified into high- and low-risk groups according to the PI value; the cut-off point was the third quartile. RESULTS: The 5-year overall survival rate was 46%, and the 5-year disease-free survival rate was 35%. Five factors were found to be independent predictors of poor overall survival (OS by multivariate analysis: positive lymph node status, vascular invasion, BRAF mutation, the distribution of bilobar liver metastases (LMs and non-R0 resection of LMs. Compared to low PI (≤5.978, high PI (>5.978 was highly predictive of shorter OS. Three factors were found to be independent predictors of poor disease-free survival (DFS by multivariate analysis: tumor deposits, BRAF mutation and bilobar LM distribution. We also determined the PI for DFS. Compared to low PI (≤2.945, high PI (>2.945 was highly predictive of shorter DFS. CONCLUSIONS: Simultaneous resection of SCRLM may lead to various long-term outcomes. Patients with low PI have longer OS and DFS, while those with high PI have shorter OS and DFS. Thus, patients with high PI may receive more aggressive treatment and intensive surveillance, This model needs further validation.

  13. Orthogonal signal correction-partial least squares method for simultaneous spectrophotometric determination of cypermethrin and tetramethrin

    Science.gov (United States)

    Niazi, Ali; Goodarzi, Mohammad

    2008-04-01

    The simultaneous determination of cypermethrin and tetramethrin mixtures by using spectrophotometric method is a difficult problem in analytical chemistry, due to spectral interferences. By multivariate calibration methods, such as partial least squares (PLS) regression, it is possible to obtain a model adjusted to the concentration values of the mixtures used in the calibration range. Orthogonal signal correction (OSC) is a preprocessing technique used for removing the information unrelated to the target variables based on constrained principal component analysis. OSC is a suitable preprocessing method for partial least squares calibration of mixtures without loss of prediction capacity using spectrophotometric method. In this study, the calibration model is based on absorption spectra in the 200-350 nm range for 25 different mixtures of cypermethrin and tetramethrin. Calibration matrices were containing 0.1-12.9 and 0.1-13.8 μg mL -1 for cypermethrin and tetramethrin, respectively. The RMSEP for cypermethrin and tetramethrin with OSC and without OSC were 0.0884, 0.0614 and 0.2915, 0.2309, respectively. This procedure allows the simultaneous determination of cypermethrin and tetramethrin in synthetic and real samples good reliability of the determination was proved.

  14. Capillary electrophoresis for simultaneous determination of emodin, chrysophanol, and their 8-beta-D-glucosides.

    Science.gov (United States)

    Koyama, Junko; Morita, Izumi; Kawanishi, Kazuko; Tagahara, Kiyoshi; Kobayashi, Norihiro

    2003-04-01

    The simultaneous separation and determination of the major anthraquinones, emodin, chrysophanol, and their glucosides, of Rumex japonicus HOUTT., and emodin and emodin glucoside, of Cassia tora L., Rhamnus purshiana DC., Polygonum multiflorum THUNB., and P. cuspidatum SIEB. et ZUCC., were achieved by cyclodextrin modified capillary zone electrophoresis. The running electrolyte used in this method was 0.005 M alpha-cyclodextrin in 0.03 M borate buffer (pH 10.5) containing 10% acetonitrile, with an applied voltage of 20 kV.

  15. Validated HPTLC method for the simultaneous determination of cinnarizine and dimenhydrinate in their combined dosage form

    OpenAIRE

    Dina S. El-Kafrawy; Tarek S. Belal

    2016-01-01

    A simple, rapid and selective high performance thin layer chromatography (HPTLC) method was developed for the simultaneous determination of cinnarizine (CNZ) and dimenhydrinate (DMH) in pure form and in their combined dosage form. Reviewing the literature revealed that there are no reports for the use of TLC for the assay of this mixture. Effective separation was achieved using Fluka HPTLC aluminum sheets of silica gel 60 F254 using chloroform–n-hexane–methanol (8.5:0.8:0.7, by volume) as mob...

  16. Simultaneous determination of Albendazol and Triclabendazole in Triclazol 22 suspension for veterinary purposes

    International Nuclear Information System (INIS)

    Garcia Penna, Caridad Margarita; Gafas Leyva, Maite; Rosales Bosch, Karina

    2013-01-01

    To validate the analytical method for simultaneous determination of triclabendazole and al bendazole in triclazol 22 suspension for quality control. For quantitation of the active principle in the final product, the separation was performed through a liquid chromatographic column Lichrosorb RP-18 (5 μm) (250 x 4 mm), with ultraviolet detection range of 298 nm, by using a mobile phase of acetonitrile: ammonium acetate buffer solution of ph 6.6 (70:30); the quantitation was made against a reference sample by means of the external standard method

  17. Simultaneous determination of aliphatic hydrocarbons, PCBs and PCTs in pork liver by gas chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez-Barros, C. [Dept. de Quimica Analitica, Nutricion y Bromatologia, Area Nutricion y Bromatologia, Facultad de Farmacia, Santiago de Compostela (Spain); Alvarez Pineiro, M.E. [Inst. de Investigacion y Analisis Alimentarios, Lab. de Bromatologia, Facultad de Farmacia, Santiago de Compostela (Spain); Simal Lozano, J. [Dept. de Quimica Analitica, Nutricion y Bromatologia, Area Nutricion y Bromatologia, Facultad de Farmacia, Santiago de Compostela (Spain); Lage Yusty, M.A. [Inst. de Investigacion y Analisis Alimentarios, Lab. de Bromatologia, Facultad de Farmacia, Santiago de Compostela (Spain)

    1996-10-01

    A multicomponent extraction/concentration procedure has been developed for the enrichment of PCBs, PCTs and aliphatic hydrocarbons (pristane, C{sub 18}, C{sub 19}, C{sub 20}, C{sub 22}, C{sub 24}, C{sub 28}, C{sub 32} and C{sub 36}) in pork liver. These components of the enriched extract were then simultaneously determined by gas chromatography. Mean recoveries ranged from 81.5% for pristane to 93% for PCBs; CV % (0.9-6.7) indicated the method to be both precise and reproducible. (orig.)

  18. Simultaneous Determination of Lamivudine, Zidovudine and Abacavir in Tablet Dosage Forms by RP HPLC Method

    OpenAIRE

    Kumar, D. Anantha; Rao, G. Srinivasa; Rao, J. V. L. N. Seshagiri

    2010-01-01

    A simple, accurate and reproducible RP-HPLC method has been developed for the simultaneous determination of lamivudine, zidovudine and abacavir in tablet dosage forms. Chromatography was carried out on a HiQ Sil C 18 V column using a mobile phase consisting of 0.01 M potassium dihydrogen ortho-phosphate (pH 3.0) and methanol (55:45 v/v) at a flow rate of 0.8 mL/min. The detection was made at 272 nm and stavudine was used as the internal standard for this study. The retention times for lamivud...

  19. Simultaneous separation and determination of hydrocarbons and organochlorine compounds by using a two-step microcolumn.

    Science.gov (United States)

    Rodriguez, O M; Desideri, P G; Lepri, L; Checchini, L

    1991-08-30

    The simultaneous separation and determination of a mixture of hydrocarbons and organochlorine compounds was successfully carried out by using sorption chromatography on a two-step microcolumn of silica and aluminium oxide for their fractionation, and a dual detector system. In addition to the separation and identification of hydrocarbons and heterocompounds containing nitrogen, oxygen and sulphur atoms, separation and identification of chlorinated hydrocarbons (dichlorobenzenes, p-chlorotoluene, hexachlorobutadiene, 1,2,4-trichlorobenzene and 2-chloronaphthalene), pesticides (chlorpicrin, aldrin, lindane, alpha- and beta-benzene hexachloride (BHC), endrin, dieldrin, endosulphan, methoxychlor) and herbicides (propanil, dichlobenil, trifluralin, difolatan) were achieved in mixtures containing polychlorinated biphenyl, strobane and chlordane.

  20. Derivative spectrophotometric method for simultaneous determination of clindamycin phosphate and tretinoin in pharmaceutical dosage forms.

    Science.gov (United States)

    Barazandeh Tehrani, Maliheh; Namadchian, Melika; Fadaye Vatan, Sedigheh; Souri, Effat

    2013-04-10

    A derivative spectrophotometric method was proposed for the simultaneous determination of clindamycin and tretinoin in pharmaceutical dosage forms. The measurement was achieved using the first and second derivative signals of clindamycin at (1D) 251 nm and (2D) 239 nm and tretinoin at (1D) 364 nm and (2D) 387 nm.The proposed method showed excellent linearity at both first and second derivative order in the range of 60-1200 and 1.25-25 μg/ml for clindamycin phosphate and tretinoin respectively. The within-day and between-day precision and accuracy was in acceptable range (CVpharmaceutical dosage form.

  1. A ratio derivative spectrophotometric method for the simultaneous determination of thorium and uranium

    International Nuclear Information System (INIS)

    Relan, G.R.; Venugopal, V.

    1999-01-01

    This paper addresses the development of a ratio derivative spectrophotometric method for the simultaneous determination of thorium and uranium at trace levels in 5M HNO 3 with a view to find its applicability in some of reprocessed materials from thorium-uranium fuels. Arsenazo III was used a chromogenic reagent and the overlapping spectra of thorium and uranium Arsenazo III complexes are resolved by making use of the first derivative of the ratios of their direct absorption spectra. A relative error of about 1% and 2% is obtained for thorium and uranium respectively. The method is simple fast and does not require prior separation. (author)

  2. Simultaneous Determination of Ciprofloxacin Hydrochloride and Dexamethasone Sodium Phosphate in Eye Drops by HPLC

    OpenAIRE

    Katakam, Prakash; Sireesha, Karanam R.

    2012-01-01

    A liquid chromatographic method was developed and validated for the simultaneous determination of ciprofloxacin hydrochloride and dexamethasone sodium phosphate in bulk and pharmaceutical formulations. Optimum separation was achieved in less than 5 min using a C18 column (250 mmx4.6 mm i.d, 5μ particle size) by isocratic elution. The mobile phase consisting of a mixture of mixed phosphate buffer (pH 4) and acetonitrile (65:35, v/v) was used. Column effluents were monitored at 254 nm at a flow...

  3. The influence of dissociation on simultaneous determination of zirconium and hafnium with xylenol orange

    International Nuclear Information System (INIS)

    Kiciak, S.; Gontarz, H.

    1980-01-01

    The molar absorptivities of the zirconium and hafnium Xylenol Orange (1:1) complexes are said to be similar in the acidity range 0.1 to 2.0 M HCl. However, the absorbances obtained for the zirconium-Xylenol Orange complex in the acidity range 0.5 to 2.0 M HCl are much higher than those for the same concentrations of hafnium. The absorbance differences are generally due to the higher stability of the zirconium complex at such acidities. Calculations based on the conditional stability constants of these complexes show the influence of dissociation on the results of simultaneous determination of zirconium and hafnium with Xylenol Orange. (author)

  4. Simultaneous and rapid determination of multiple component concentrations in a Kraft liquor process stream

    Science.gov (United States)

    Li, Jian [Marietta, GA; Chai, Xin Sheng [Atlanta, GA; Zhu, Junyoung [Marietta, GA

    2008-06-24

    The present invention is a rapid method of determining the concentration of the major components in a chemical stream. The present invention is also a simple, low cost, device of determining the in-situ concentration of the major components in a chemical stream. In particular, the present invention provides a useful method for simultaneously determining the concentrations of sodium hydroxide, sodium sulfide and sodium carbonate in aqueous kraft pulping liquors through use of an attenuated total reflectance (ATR) tunnel flow cell or optical probe capable of producing a ultraviolet absorbency spectrum over a wavelength of 190 to 300 nm. In addition, the present invention eliminates the need for manual sampling and dilution previously required to generate analyzable samples. The inventive method can be used in Kraft pulping operations to control white liquor causticizing efficiency, sulfate reduction efficiency in green liquor, oxidation efficiency for oxidized white liquor and the active and effective alkali charge to kraft pulping operations.

  5. Radium 226 and uranium isotopes simultaneously determination in water samples using liquid scintillation counter

    International Nuclear Information System (INIS)

    Al-Masri, M.S.; Al-Akel, B.; Saaid, S.; Nashawati, A.

    2007-04-01

    In this work a method has been developed to determine simultaneously Radium 226 and Uranium isotopes in water samples by low back ground Liquid Scintillation Counter. Radium 226 was determined by its progeny Polonium 214 after one month of sample storage in order to achieve the equilibrium between Radium 226 and Polonium 214. Uranium isotopes were determined by subtracting Radium 226 activity from total alpha activity. The method detection limits were 0.049 Bq/L and 0.176 Bq/L for Radium 226 and Uranium isotopes respectively. The repeatability limits were ± 0.32 Bq/L and ± 0.9 Bq/L for Radium 226 and Uranium isotopes respectively. While relative errors were % 9.5 and %18.2 for Radium 226 and Uranium isotopes respectively. On the other hand, the report presented the results of different standard and natural samples.(author)

  6. Simultaneous determination of uranium(VI) and thorium(IV) with carminic acid by derivative spectrophotometry

    International Nuclear Information System (INIS)

    Lopez-de-Alba, P.L.; Lopez-Martinez, L.

    1992-01-01

    The reactions of uranium(VI) and thorium(IV) ions with carminic acid have been investigated. These ions react with carminic acid in neutral medium, forming colored complexes. The dark purple or red wine complexes show a high absorption in the visible region (597 nm U(VI) and 616 nm Th(IV)). Chemical variables that affect the reaction have been optimized. The spectral overlapping of the color of complexes has been resolved by first-derivative spectrophotometry. The simultaneous determination of uranium(VI) and thorium(IV) mixtures is accomplished by taking the derivative signal ('zero crossing') at 597 nm for U(VI) determination and at 616 nm for Th(IV) determination, respectively. The method has been applied to Tyuyamonite ore, containing in the matrix both ions. (author) 11 refs.; 3 figs.; 3 tabs

  7. Simultaneous determination of vitamin B12 and its derivatives using some of multivariate calibration 1 (MVC1) techniques

    Science.gov (United States)

    Samadi-Maybodi, Abdolraouf; Darzi, S. K. Hassani Nejad

    2008-10-01

    Resolution of binary mixtures of vitamin B12, methylcobalamin and B12 coenzyme with minimum sample pre-treatment and without analyte separation has been successfully achieved by methods of partial least squares algorithm with one dependent variable (PLS1), orthogonal signal correction/partial least squares (OSC/PLS), principal component regression (PCR) and hybrid linear analysis (HLA). Data of analysis were obtained from UV-vis spectra. The UV-vis spectra of the vitamin B12, methylcobalamin and B12 coenzyme were recorded in the same spectral conditions. The method of central composite design was used in the ranges of 10-80 mg L -1 for vitamin B12 and methylcobalamin and 20-130 mg L -1 for B12 coenzyme. The models refinement procedure and validation were performed by cross-validation. The minimum root mean square error of prediction (RMSEP) was 2.26 mg L -1 for vitamin B12 with PLS1, 1.33 mg L -1 for methylcobalamin with OSC/PLS and 3.24 mg L -1 for B12 coenzyme with HLA techniques. Figures of merit such as selectivity, sensitivity, analytical sensitivity and LOD were determined for three compounds. The procedure was successfully applied to simultaneous determination of three compounds in synthetic mixtures and in a pharmaceutical formulation.

  8. Simultaneous separation and determination of 15 organic UV filters in sunscreen cosmetics by HPLC-ESI-MS/MS.

    Science.gov (United States)

    Meng, X; Ma, Q; Bai, H; Wang, Z; Han, C; Wang, C

    2017-08-01

    A comprehensive methodology for the simultaneous determination of 15 multiclass organic UV filters in sunscreen cosmetics was developed using high-performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry (HPLC-ESI-MS/MS). Sunscreen cosmetics of various matrices, such as toning lotion, emulsion, cream and lipstick, were analysed. Ultrasound-assisted extraction (UAE) was utilized as the extraction technique for sample preparation. The 15 UV filters were chromatographically separated by two groups of mobile phase system on an XBridge C 18 analytical column (150 × 2.1 mm I.D., 3.5 μm particle size) and quantified using HPLC-ESI-MS/MS. The quantitation was performed using the external calibration method. The established method was validated in terms of linearity, sensitivity, specificity, accuracy, stability, intraday and interday precisions, recovery and matrix effect. The method was also applied for the determination of UV filters in commercial sunscreen cosmetics. The experimental results demonstrated that the developed method was accurate, rapid and sensitive and can be used for the analytical control of sunscreen cosmetics. © 2016 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

  9. Simultaneous trace multielement determination by ICP-OES after solid phase extraction with modified octadecyl silica gel.

    Science.gov (United States)

    Karbasi, Mohamad-Hadi; Jahanparast, Babak; Shamsipur, Mojtaba; Hassan, Jalal

    2009-10-15

    Multielement simultaneous determination of 35 trace elements in environmental samples was carried out by inductively coupled plasma emission spectrometry (ICP-OES) after preconcentration with octadecyl silicagel, modified with aurin tricarboxylic acid (Aluminon). Optimal experimental conditions including pH of sample solution, sample volume, sample and eluent flow rate, type, concentration and volume of eluent and foreign ions effect were investigated and established. Trace element ions in aqueous solution were quantitatively adsorbed onto octadecyl silicagel modified with aurin tricarboxylic acid at pH 8.0 with a flow rate of 11.0 mL min(-1). The adsorbed element ions were eluted with 3-5 mL of 0.5 mol L(-1) HNO(3) at a flow rate of 10.0 mL min(-1) and analyzed by ICP-OES simultaneously. The proposed method has at least preconcentration factor of 100 in water samples, which results high sensitive detection of ultra-trace and trace analysis. The present methodology gave recoveries better than 70% and RSD less than 16%.

  10. LiNbO3 :Pr3+ : A Multipiezo Material with Simultaneous Piezoelectricity and Sensitive Piezoluminescence.

    Science.gov (United States)

    Tu, Dong; Xu, Chao-Nan; Yoshida, Akihito; Fujihala, Masayoshi; Hirotsu, Jou; Zheng, Xu-Guang

    2017-06-01

    Red-emitting piezoluminescence (elasticoluminescence) is achieved by doping rare earth Pr 3+ into the well-known piezoelectric matrix, LiNbO 3 . By precisely tuning the Li/Nb ratio in nonstoichiometric Li x NbO 3 :Pr 3+ , a material that exhibits an unusually high piezoluminescence intensity, which far exceeds that of any well-known piezoelectric material, is produced. Li x NbO 3 :Pr 3+ shows excellent strain sensitivity at the lowest strain level, with no threshold for stress sensing. These multipiezo properties of sensitive piezoluminescence in a piezoelectric matrix are ideal for microstress sensing, damage diagnosis, electro-mechano-optical energy conversion, and multifunctional control in optoelectronics. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. The Maillard Reaction Reduced the Sensitization of Tropomyosin and Arginine Kinase from Scylla paramamosain, Simultaneously.

    Science.gov (United States)

    Han, Xin-Yu; Yang, Huang; Rao, Shi-Tao; Liu, Guang-Yu; Hu, Meng-Jun; Zeng, Bin-Chang; Cao, Min-Jie; Liu, Guang-Ming

    2018-03-21

    The Maillard reaction was established to reduce the sensitization of tropomyosin (TM) and arginine kinase (AK) from Scylla paramamosain, and the mechanism of the attenuated sensitization was investigated. In the present study, the Maillard reaction conditions were optimized for heating at 100 °C for 60 min (pH 8.5) with arabinose. A low level of allergenicity in mice was shown by the levels of allergen-specific antibodies, and more Th1 and less Th2 cells cytokines produced and associated transcription factors with the Maillard reacted allergen (mAllergen). The tolerance potency in mice was demonstrated by the increased ratio of Th1/Th2 cytokines. Moreover, mass spectrometry analysis showed that some key amino acids of IgE-binding epitopes (K 112 , R 125 , R 133 of TM; K 33 , K 118 , R 202 of AK) were modified by the Maillard reaction. The Maillard reaction with arabinose reduced the sensitization of TM and AK, which may be due to the masked epitopes.

  12. Simultaneous spectrophotometric determination of mercury and palladium with Thio-Michler's Ketone using partial least squares regression and orthogonal signal correction

    Science.gov (United States)

    Niazi, Ali; Azizi, Amir; Ramezani, Majid

    2008-12-01

    A simple, novel and sensitive spectrophotometric method was described for simultaneous determination of mercury and palladium. The method is based on the complex formation of mercury and palladium with Thio-Michler's Ketone (TMK) at pH 3.5. All factors affecting on the sensitivity were optimized and the linear dynamic range for determination of mercury and palladium found. The simultaneous determination of mercury and palladium mixtures by using spectrophotometric method is a difficult problem, due to spectral interferences. By multivariate calibration methods such as partial least squares (PLS), it is possible to obtain a model adjusted to the concentration values of the mixtures used in the calibration range. Orthogonal signal correction (OSC) is a preprocessing technique used for removing the information unrelated to the target variables based on constrained principal component analysis. OSC is a suitable preprocessing method for PLS calibration of mixtures without loss of prediction capacity using spectrophotometric method. In this study, the calibration model is based on absorption spectra in the 360-660 nm range for 25 different mixtures of mercury and palladium. Calibration matrices were containing 0.025-1.60 and 0.05-0.50 μg mL -1 of mercury and palladium, respectively. The RMSEP for mercury and palladium with OSC and without OSC were 0.013, 0.006 and 0.048, 0.030, respectively. This procedure allows the simultaneous determination of mercury and palladium in synthetic and real matrix samples good reliability of the determination.

  13. Simultaneous detection of high-sensitivity cardiac troponin I and myoglobin by modified sandwich lateral flow immunoassay: proof of principle.

    Science.gov (United States)

    Zhu, Jimin; Zou, Nengli; Zhu, Danian; Wang, Jin; Jin, Qinghui; Zhao, Jianlong; Mao, Hongju

    2011-12-01

    Although numerous lateral flow immunoassays (LFIAs) have been developed and widely used, inadequate analytical sensitivity and the lack of multiple protein detection applications have limited their clinical utility. We developed a new LFIA device for the simultaneous detection of high-sensitivity cardiac troponin I (hs-cTnI) and myoglobin (Myo). We used a gold nanoparticle (AuNP) doubly labeled complex, in which biotinylated single-stranded DNA was used as a linkage to integrate 2 AuNPs and streptavidin-labeled AuNP, as an amplifier to magnify extremely low signals. The detection limit of 1 ng/L achieved for hs-cTnI was 1000 times lower than that obtained in a conventional LFIA. The detection limit for simultaneously measured Myo was 1 μg/L. The linear measurement ranges for hs-cTnI and Myo were 1-10 000 ng/L and 1-10 000 μg/L, respectively. We observed concordant results between the LFIA and clinical assays in sera from 12 patients with acute myocardial infarction (hs-cTnI r = 0.96; Myo r = 0.98). Assay imprecision was LFIA method could be used as a point-of-care device in multiple protein quantification and semiquantitative analysis.

  14. Simultaneous determination of caffeine, theobromine, and theophylline by high-performance liquid chromatography.

    Science.gov (United States)

    Bispo, Marcia S; Veloso, Márcia Cristina C; Pinheiro, Heloísa Lúcia C; De Oliveira, Rodolfo F S; Reis, José Oscar N; De Andrade, Jailson B

    2002-01-01

    This work relates the development of an analytical methodology to simultaneously determine three methylxanthines (caffeine, theobromine, and theophylline) in beverages and urine samples based on reversed-phase high-performance liquid chromatography. Separation is made with a Bondesil C18 column using methanol-water-acetic acid or ethanol-water-acetic acid (20:75:5, v/v/v) as the mobile phase at 0.7 mL/min. Identification is made by absorbance detection at 273 nm. Under optimized conditions, the detection limit of the HPLC method is 0.1 pg/mL for all three methylxanthines. This method is applied to urine and to 25 different beverage samples, which included coffee, tea, chocolate, and coconut water. The concentration ranges determined in the beverages and urine are: theobromine; < 0.1 pg/mL to 47 microg/mL and < 0.1 pg/mL to 66.3 microg/mL for theophylline. The method proposed in this study is rapid and suitable for the simultaneous quantitation of methylxanthines in beverages and human urine samples and requires no extraction step or derivatization.

  15. [Simultaneous determination of pantothenic acid and D-panthenol in cosmetics by high performance liquid chromatography].

    Science.gov (United States)

    Mao, Xiqin; Hu, Xia; Pan, Wei

    2010-11-01

    A high performance liquid chromatographic method (HPLC) and sample pretreatment method were developed for the simultaneous determination of pantothenic acid (vitamin B5) and D-panthenol (provitamin B5) in cosmetics with different matrices (including of creams, lotions, aqueous cosmetics, oily cosmetics, wax-based cosmetics, nail polish etc). A liquid-liquid extraction system composed of water and water-immiscible solvent was used to preliminarily separate the target components from other oil-soluble components and surfactants in cosmetics, then macromolecular water-soluble matrices in cosmetics were removed by coprecipitation with potassium ferrocyanide-zinc acetate precipitating agent, and then under acid condition, pantothenic acid and D-panthenol were enriched on a C18 solid-phase extraction sorbent. After the removal of other water-soluble impurities, target components were eluted by 40% methanol and then separated and quantitatively analyzed by high performance liquid chromatography with external standard method. Good linear relationship was achieved in the concentration range of 0.1-10 microg/g for pantothenic acid and D-panthenol. The linear correlation coefficients were separately 0.998 9 and 0.999 6. The average recoveries of the target components in cosmetics were more than 90%. Limit of detection of the method was 30 microg/g and the limit of quantification was 100 microg/g. This method can be used to simultaneously determine pantothenic acid and D-panthenol in cosmetics. The results are accurate and reliable.

  16. Simultaneous spectrophotometric determination of uranium and zirconium using cloud point extraction and multivariate methods

    International Nuclear Information System (INIS)

    Ghasemi, Jahan B.; Hashemi, Beshare; Shamsipur, Mojtaba

    2012-01-01

    A cloud point extraction (CPE) process using the nonionic surfactant Triton X-114 to simultaneous extraction and spectrophotometric determination of uranium and zirconium from aqueous solution using partial least squares (PLS) regression is investigated. The method is based on the complexation reaction of these cations with Alizarin Red S (ARS) and subsequent micelle-mediated extraction of products. The chemical parameters affecting the separation phase and detection process were studied and optimized. Under the optimum experimental conditions (i.e. pH 5.2, Triton X-114 = 0.20%, equilibrium time 10 min and cloud point 45 C), calibration graphs were linear in the range of 0.01-3 mg L -1 with detection limits of 2.0 and 0.80 μg L -1 for U and Zr, respectively. The experimental calibration set was composed of 16 sample solutions using an orthogonal design for two component mixtures. The root mean square error of predictions (RMSEPs) for U and Zr were 0.0907 and 0.1117, respectively. The interference effect of some anions and cations was also tested. The method was applied to the simultaneous determination of U and Zr in water samples.

  17. Simultaneous spectrophotometric determination of paracetamol, ibuprofen and caffeine in pharmaceuticals by chemometric methods

    Science.gov (United States)

    Khoshayand, M. R.; Abdollahi, H.; Shariatpanahi, M.; Saadatfard, A.; Mohammadi, A.

    2008-08-01

    In this study, the simultaneous determination of paracetamol, ibuprofen and caffeine in pharmaceuticals by chemometric approaches using UV spectrophotometry has been reported as a simple alternative to using separate models for each component. Spectra of paracetamol, ibuprofen and caffeine were recorded at several concentrations within their linear ranges and were used to compute the calibration mixture between wavelengths 200 and 400 nm at an interval of 1 nm in methanol:0.1 HCl (3:1). Partial least squares regression (PLS), genetic algorithm coupled with PLS (GA-PLS), and principal component-artificial neural network (PC-ANN) were used for chemometric analysis of data and the parameters of the chemometric procedures were optimized. The analytical performances of these chemometric methods were characterized by relative prediction errors and recoveries (%) and were compared with each other. The GA-PLS shows superiority over other applied multivariate methods due to the wavelength selection in PLS calibration using a genetic algorithm without loss of prediction capacity. Although the components show an important degree of spectral overlap, they have been determined simultaneously and rapidly requiring no separation step. These three methods were successfully applied to pharmaceutical formulation, capsule, with no interference from excipients as indicated by the recovery study results. The proposed methods are simple and rapid and can be easily used in the quality control of drugs as alternative analysis tools.

  18. Application of Scion image software to the simultaneous determination of curcuminoids in turmeric (Curcuma longa).

    Science.gov (United States)

    Sotanaphun, Uthai; Phattanawasin, Panadda; Sriphong, Lawan

    2009-01-01

    Curcumin, desmethoxycurcumin and bisdesmethoxycurcumin are bioactive constituents of turmeric (Curcuma longa). Owing to their different potency, quality control of turmeric based on the content of each curcuminoid is more reliable than that based on total curcuminoids. However, to perform such an assay, high-cost instrument is needed. To develop a simple and low-cost method for the simultaneous quantification of three curcuminoids in turmeric using TLC and the public-domain software Scion Image. The image of a TLC chromatogram of turmeric extract was recorded using a digital scanner. The density of the TLC spot of each curcuminoid was analysed by the Scion Image software. The density value was transformed to concentration by comparison with the calibration curve of standard curcuminoids developed on the same TLC plate. The polynomial regression data for all curcuminoids showed good linear relationship with R(2) > 0.99 in the concentration range of 0.375-6 microg/spot. The limits of detection and quantitation were 43-73 and 143-242 ng/spot, respectively. The method gave adequate precision, accuracy and recovery. The contents of each curcuminoid determined using this method were not significantly different from those determined using the TLC densitometric method. TLC image analysis using Scion Image is shown to be a reliable method for the simultaneous analysis of the content of each curcuminoid in turmeric.

  19. Simultaneous Determination of Ciprofloxacin Hydrochloride and Dexamethasone Sodium Phosphate in Eye Drops by HPLC

    Directory of Open Access Journals (Sweden)

    Prakash Katakam

    2012-01-01

    Full Text Available A liquid chromatographic method was developed and validated for the simultaneous determination of ciprofloxacin hydrochloride and dexamethasone sodium phosphate in bulk and pharmaceutical formulations. Optimum separation was achieved in less than 5 min using a C18 column (250 mmx4.6 mm i.d, 5μ particle size by isocratic elution. The mobile phase consisting of a mixture of mixed phosphate buffer (pH 4 and acetonitrile (65:35, v/v was used. Column effluents were monitored at 254 nm at a flow rate of 1ml/min. Retention times of ciprofloxacin hydrochloride and dexamethasone sodium phosphate were 2.0 and 3.16 min respectively. The linearity of ciprofloxacin hydrochloride and dexamethasone sodium phosphate was in the range of 3-18 μg/ml and 1-6 μg/ml respectively. Developed method was economical in terms of the time taken and amount of solvent consumed for each analysis. The method was validated and successfully applied to the simultaneous determination of ciprofloxacin hydrochloride and dexamethasone sodium phosphate in bulk and pharmaceutical formulations.

  20. Multi-residue fluorescent microspheres immunochromatographic assay for simultaneous determination of macrolides in raw milk.

    Science.gov (United States)

    Li, Xiangmei; Shen, Jianzhong; Wang, Qi; Gao, Shuxia; Pei, Xingyao; Jiang, Haiyang; Wen, Kai

    2015-12-01

    A rapid, reliable, sensitive, and quantitative multi-residue fluorescent microspheres immunochromatographic assay (FMCA) was developed for simultaneous detection of four macrolides in raw milk. The IC50 value of the optimized FMCA was 1.36, 1.22, 1.01, and 1.39 ng/mL for erythromycin (ERY), spiramycin (SPI), tilmicosin (TIM), and tylosin (TYL), respectively. The limits of detection (LODs) for the four macrolides was 0.13 ng/mL. The recoveries of ERY, SPI, TIM, and TYL from spiked raw milk ranged from 91.8-109.2, 89.6-114.4, 84.8-111.6, and 85.8-115.2%, respectively, with coefficients of variation (CVs) of 5.4-11.3, 7.9-15.7, 6.2-13.7, and 3.2-14.9%, respectively. The whole testing process was completed within 20 min. The antibody-mixed labeled method was successfully applied to the FMCA, which greatly simplified the operation steps and saved a lot of time. Compared with the immunogold chromatographic assay (IGCA), the FMCA is more sensitive and stable and has less antibody consumption. A parallel analysis in blind raw milk samples was conducted by liquid chromatography-tandem mass spectrometry (LC-MS/MS); the results showed good correlation (r(2) = 0.99) between the two methods. Therefore, the developed multi-residue FMCA is reliable and can be easily applied to other antibiotics or other contaminants.

  1. Study on performance of a simultaneous spectrometer of ICP emission source for the determination of the major elements in rocks

    International Nuclear Information System (INIS)

    Vieira, M.D.

    1987-01-01

    The optimization of operational parameters of a simultaneous spectrometer coupled to an ICP excitation source in order to establish an analytical method for the simultaneous determination of the major elements in rocks is studied. The mutual spectral interferences, calibration curves for the acid and saline matrix and the internal standard method with ytrium are analyzed. (M.J.C.) [pt

  2. Simultaneous quantitative detection of multiple tumor markers with a rapid and sensitive multicolor quantum dots based immunochromatographic test strip.

    Science.gov (United States)

    Wang, Chunying; Hou, Fei; Ma, Yicai

    2015-06-15

    A novel multicolor quantum dots (QDs) based immunochromatographic test strip (ICTS) was developed for simultaneous quantitative detection of multiple tumor markers, by utilizing alpha fetoprotein (AFP) and carcinoembryonic antigen (CEA) as models. The immunosensor could realize simultaneous quantitative detection of tumor markers with only one test line and one control line on the nitrocellulose membrane (NC membrane) due to the introduction of multicolor QDs. In this method, a mixture of mouse anti-AFP McAb and mouse anti-CEA McAb was coated on NC membrane as test line and goat anti-mouse IgG antibody was coated as control line. Anti-AFP McAb-QDs546 conjugates and anti-CEA McAb-QDs620 conjugates were mixed and applied to the conjugate pad. Simultaneous quantitative detection of multiple tumor markers was achieved by detecting the fluorescence intensity of captured QDs labels on test line and control line using a test strip reader. Under the optimum conditions, AFP and CEA could be detected as low as 3 ng/mL and 2 ng/mL in 15 min with a sample volume of 80 μL, and no obvious cross-reactivity was observed. The immunosensor was validated with 130 clinical samples and in which it exhibited high sensitivity (93% for AFP and 87% for CEA) and specificity (94% for AFP and 97% for CEA). The immunosensor also demonstrated high recoveries (87.5-113% for AFP and 90-97.3% for CEA) and low relative standard deviations (RSDs) (2.8-6.2% for AFP and 4.9-9.6% for CEA) when testing spiked human serum. This novel multicolor QDs based ICTS provides an easy and rapid, simultaneous quantitative detecting strategy for point-of-care testing of tumor markers. Copyright © 2014 Elsevier B.V. All rights reserved.

  3. New method for simultaneous determination of 55Fe and 59Fe in blood serum samples

    International Nuclear Information System (INIS)

    Saukkonen, H.; Uhlenius, R.

    1978-01-01

    Routine methods for the measurement of 55 Fe and 59 Fe activities in biological samples are frequently required in metabolic studies of iron. A new simple method for the simultaneous determination of 59 Fe and 55 Fe concentration in 5 cm 3 samples of blood is described and carefully evaluated. Before the measurement of the activity, organic matter was eliminated by HNO 3 -HClO 4 wet ashing and iron was electroplated onto a copper plate. The accuracy of results was studied by assessing samples, which contained known amounts of radioactivity and determining the counts per nanocurie in each case. The accuracy of the results of 59 Fe and 55 Fe determinations was found to be about 5%. The method has been routinely used to determine iron resorption in patients using the double isotope method. The determination proved to be satisfactory and not too laborious. When performing the yield determination there is a way of detecting and correcting mistakes or incompleteness in different stages of the measurement, thus leading to a high degree of reliability. (T.G.)

  4. Biological optimization of simultaneous boost on intra-prostatic lesions (DILs): sensitivity to TCP parameters.

    Science.gov (United States)

    Azzeroni, R; Maggio, A; Fiorino, C; Mangili, P; Cozzarini, C; De Cobelli, F; Di Muzio, N G; Calandrino, R

    2013-11-01

    The aim of this investigation was to explore the potential of biological optimization in the case of simultaneous integrated boost on intra-prostatic dominant lesions (DIL) and evaluating the impact of TCP parameters uncertainty. Different combination of TCP parameters (TD50 and γ50 in the Poisson-like model), were considered for DILs and the prostate outside DILs (CTV) for 7 intermediate/high-risk prostate patients. The aim was to maximize TCP while constraining NTCPs below 5% for all organs at risk. TCP values were highly depending on the parameters used and ranged between 38.4% and 99.9%; the optimized median physical doses were in the range 94-116 Gy and 69-77 Gy for DIL and CTV respectively. TCP values were correlated with the overlap PTV-rectum and the minimum distance between rectum and DIL. In conclusion, biological optimization for selective dose escalation is feasible and suggests prescribed dose around 90-120 Gy to the DILs. The obtained result is critically depending on the assumptions concerning the higher radioresistence in the DILs. In case of very resistant clonogens into the DIL, it may be difficult to maximize TCP to acceptable levels without violating NTCP constraints. Copyright © 2012 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  5. Development of an ELISA microarray assay for the sensitive and simultaneous detection of ten biodefense toxins.

    Energy Technology Data Exchange (ETDEWEB)

    Jenko, Kathryn; Zhang, Yanfeng; Kostenko, Yulia; Fan, Yongfeng; Garcia-Rodriguez, Consuelo; Lou, Jianlong; Marks, James D.; Varnum, Susan M.

    2014-10-21

    Plant and microbial toxins are considered bioterrorism threat agents because of their extreme toxicity and/or ease of availability. Additionally, some of these toxins are increasingly responsible for accidental food poisonings. The current study utilized an ELISA-based protein antibody microarray for the multiplexed detection of ten biothreat toxins, botulinum neurotoxins (BoNT) A, B, C, D, E, F, ricin, shiga toxins 1 and 2 (Stx), and staphylococcus enterotoxin B (SEB), in buffer and complex biological matrices. The multiplexed assay displayed a sensitivity of 1.3 pg/mL (BoNT/A, BoNT/B, SEB, Stx-1 and Stx-2), 3.3 pg/mL (BoNT/C, BoNT/E, BoNT/F) and 8.2 pg/mL (BoNT/D, ricin). All assays demonstrated high accuracy (75-120 percent recovery) and reproducibility (most coefficients of variation < 20%). Quantification curves for the ten toxins were also evaluated in clinical samples (serum, plasma, nasal fluid, saliva, stool, and urine) and environmental samples (apple juice, milk and baby food) with overall minimal matrix effects. The multiplex assays were highly specific, with little crossreactivity observed between the selected toxin antibodies. The results demonstrate a multiplex microarray that improves current immunoassay sensitivity for biological warfare agents in buffer, clinical, and environmental samples.

  6. Stability Indicating Liquid Chromatographic Method for Simultaneous determination of Aspirin and Omeprazole.

    Science.gov (United States)

    Patel, Vandana B; Patel, Aishwarya D; Shah, Dimal A

    2017-10-23

    Aspirin combination is prescribed for the its thrombolytic activity where gastric ulceration is the major side effects of aspirin which can be prevented by combining it with proton pump inhibitor omeprazole. Present study describes development of analytical method for the estimation of aspirin and omeprazole in combination. Objective of the present study was to develop and validate chromatographic method for simultaneous analysis of aspirin and omeprazole. Isocratic, reversed phase stability indicating liquid chromatographic method was developed for the simultaneous determination of Aspirin and Omeprazole in combination. The separation was achieved on a Thermo Scientific Hypersil ODS (250 x 4.6 mm, 5 µm) column, kept at ambient temperature, using acetonitrile: methanol: 0.05 M phosphate buffer (40:5:55; pH 4 adjusted with 0.1% tri ethyl amine) as a mobile phase at a flow rate of 1 mL/min and UV detection was performed at 225 nm. The retention time was found to be 3.9 min for aspirin and 5.3 min for omeprazole. The method was oberved to be linear in the range of 2 - 80 μg/mL for aspirin and 1 - 40 μg/mL for omeprazole, respectively. The proposed method was validated as per ICH guidelines Q2 (R1). The developed RP- HPLC method was successfully applied for the simultaneous estimation of aspirin and omeprazole in the presence of degradation products of both the drugs. The present study describes liquid chromatographic method for the estimation of aspirin and omeprzole in combination. The method can be used for the analysis of stability samples and routine quality control samples. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  7. Determinants of mating and sperm-transfer success in a simultaneous hermaphrodite.

    Science.gov (United States)

    Janicke, T; Schärer, L

    2009-02-01

    The number of mating partners an individual has within a population is a crucial parameter in sex allocation theory for simultaneous hermaphrodites because it is predicted to be one of the main parameters influencing sex allocation. However, little is known about the factors that determine the number of mates in simultaneous hermaphrodites. Furthermore, in order to understand the benefits obtained by resource allocation into the male function it is important to identify the factors that predict sperm-transfer success, i.e. the number of sperm a donor manages to store in a mate. In this study we experimentally tested how social group size (i.e. the number of all potential mates within a population) and density affect the number of mates and sperm-transfer success in the outcrossing hermaphroditic flatworm Macrostomum lignano. In addition, we assessed whether these parameters covary with morphological traits, such as body size, testis size and genital morphology. For this we used a method, which allows tracking sperm of a labelled donor in an unlabelled mate. We found considerable variation in the number of mates and sperm-transfer success between individuals. The number of mates increased with social group size, and was higher in worms with larger testes, but there was no effect of density. Similarly, sperm-transfer success was affected by social group size and testis size, but in addition this parameter was influenced by genital morphology. Our study demonstrates for the first time that the social context and the morphology of sperm donors are important predictors of the number of mates and sperm-transfer success in a simultaneous hermaphrodite. Based on these findings, we hypothesize that sex allocation influences the mating behaviour and outcome of sperm competition.

  8. Physical determinants of radiation sensitivity in bacterial spores

    International Nuclear Information System (INIS)

    Powers, E.L.

    1982-01-01

    Several factors modifying radiation sensitivity in dry bacterial spores are described and discussed. Vacuum inducing the loss of critical structural water, very low dose rates of radiation from which the cell may recover, radiations of high linear energy transfer, and the action of temperature over long periods of time on previously irradiated cells are recognized from extensive laboratory work as important in determining survival of spores exposed to low radiation doses at low temperatures for long periods of time. Some extensions of laboratory work are proposed

  9. Simultaneous determination of organochlorine and pyrethriod pesticide residues in the Chinese patent medicines by gas chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Mao, Xue J; Zhong, Yao; Yan, Ai P; Wang, Bin; Wang, Yuan X; Wan, Yi Q

    2018-02-01

    A simple, sensitive, reliable method was developed for the simultaneous determination of organochlorine and pyrethriod pesticide residues in Chinese patent medicines Six ingredient rehmannia pills and Xiaoyao pills. These pesticides were extracted by ethyl acetate. The extraction time and volume of ethyl acetate were optimized. Cleanup of extracts was performed with dispersive-solid phase extraction using graphitized carbon black as the sorbent. The determination of pesticides in the final extracts was carried out by gas chromatography-tandem mass spectrometry in multiple reaction monitoring mode (GC-MS/MS, MRM). The linearity of the calibration curves is good in matrix-matched standard and yields the coefficients of determination (R 2 ) ≥0.99 for all of the target analytes. Under optimized conditions, the average recoveries (five replicates) for most pesticides range from 75.5% to 114.6%, and RSDs are less than 10.0%. The LODs of 18 pesticides in Six ingredient rehmannia pill and Xiaoyao pills are in the range of 0.01-8.82 μg kg -1 . The developed method meets the requirements of pesticide residue analysis and could be effectively used for routine analysis of the organochlorine and pyrethriod pesticide residues in Six ingredient rehmannia pills and Xiaoyao pills.

  10. Simultaneous Determination of Multi-Mycotoxins in Cereal Grains Collected from South Korea by LC/MS/MS

    Directory of Open Access Journals (Sweden)

    Dong-Ho Kim

    2017-03-01

    Full Text Available An improved analytical method compared with conventional ones was developed for simultaneous determination of 13 mycotoxins (deoxynivalenol, nivalenol, 3-acetylnivalenol, aflatoxin B1, aflatoxin B2, aflatoxin G1, aflatoxin G2, fumonisin B1, fumonisin B2, T-2, HT-2, zearalenone, and ochratoxin A in cereal grains by liquid chromatography-tandem mass spectrometry (LC/MS/MS after a single immunoaffinity column clean-up. The method showed a good linearity, sensitivity, specificity, and accuracy in mycotoxin determination by LC/MS/MS. The levels of 13 mycotoxins in 5 types of commercial grains (brown rice, maize, millet, sorghum, and mixed cereal from South Korea were determined in a total of 507 cereal grains. Mycotoxins produced from Fusarium sp. (fumonisins, deoxynivalenol, nivalenol, and zearalenone were more frequently (more than 5% and concurrently detected in all cereal grains along with higher mean levels (4.3–161.0 ng/g in positive samples than other toxins such as aflatoxins and ochratoxin A (less than 9% and below 5.2 ng/g in positive samples from other fungal species.

  11. Simultaneous determination of 30 ginsenosides in Panax ginseng preparations using ultra performance liquid chromatography

    Science.gov (United States)

    Park, Hee-Won; In, Gyo; Han, Sung-Tai; Lee, Myoung-Woo; Kim, So-Young; Kim, Kyung-Tack; Cho, Byung-Goo; Han, Gyeong-Ho; Chang, Il-Moo

    2013-01-01

    A quick and simple method for simultaneous determination of the 30 ginsenosides (ginsenoside Ro, Rb1, Rb2, Rc, Rd, Re, Rf, Rg1, 20(S)-Rg2, 20(R)-Rg2, 20(S)-Rg3, 20(R)-Rg3, 20(S)-Rh1, 20(S)-Rh2, 20(R)-Rh2, F1, F2, F4, Ra1, Rg6, Rh4, Rk3, Rg5, Rk1, Rb3, Rk2, Rh3, compound Y, compound K, and notoginsenoside R1) in Panax ginseng preparations was developed and validated by an ultra performance liquid chromatography photo diode array detector. The separation of the 30 ginsenosides was efficiently undertaken on the Acquity BEH C-18 column with gradient elution with phosphoric acids. Especially the chromatogram of the ginsenoside Ro was dramatically enhanced by adding phosphoric acid. Under optimized conditions, the detection limits were 0.4 to 1.7 mg/L and the calibration curves of the peak areas for the 30 ginsenosides were linear over three orders of magnitude with a correlation coefficients greater than 0.999. The accuracy of the method was tested by a recovery measurement of the spiked samples which yielded good results of 89% to 118%. From these overall results, the proposed method may be helpful in the development and quality of P. ginseng preparations because of its wide range of applications due to the simultaneous analysis of many kinds of ginsenosides. PMID:24235860

  12. Validated HPTLC method for the simultaneous determination of cinnarizine and dimenhydrinate in their combined dosage form

    Directory of Open Access Journals (Sweden)

    Dina S. El-Kafrawy

    2016-02-01

    Full Text Available A simple, rapid and selective high performance thin layer chromatography (HPTLC method was developed for the simultaneous determination of cinnarizine (CNZ and dimenhydrinate (DMH in pure form and in their combined dosage form. Reviewing the literature revealed that there are no reports for the use of TLC for the assay of this mixture. Effective separation was achieved using Fluka HPTLC aluminum sheets of silica gel 60 F254 using chloroform–n-hexane–methanol (8.5:0.8:0.7, by volume as mobile phase, followed by densitometric measurement of CNZ and DMH spots at 254 and 279 nm, respectively. The reliability and analytical performance of the proposed HPTLC method were statistically validated with respect to linearity, ranges, precision, accuracy, selectivity, robustness and detection and quantification limits. Calibration curves were linear in the ranges of 50–400 and 50–500 ng/spot for CNZ and DMH, respectively with correlation coefficients >0.9998. The limits of detection were 8.1 and 8.0 ng/spot for CNZ and DMH respectively. The validated HPTLC method was applied to the simultaneous analysis of CNZ and DMH in laboratory-prepared tablets. Both analytes were successfully quantified with good recovery values, and no interference was encountered from the inactive ingredients.

  13. Quality evaluation of Huaijiao pill by chromatographic fingerprint and simultaneous determination of its major bioactive components

    Directory of Open Access Journals (Sweden)

    Shuangqin Wang

    2016-08-01

    Full Text Available For quality control purpose, an approach of combining chromatographic fingerprint of Huaijiao pill (HP and simultaneous determination of its major bioactive components was developed using high performance liquid chromatography coupled with diode array detector (HPLC--DAD. For fingerprint analysis, 16 peaks were selected as the characteristic peaks to evaluate the similarities of different samples collected from different batches of three manufacturers. The similarities of 17 Huaijiao pill samples were beyond 0.966, indicating that samples from different batches and manufacturers were, to some extent, consistent. Additionally, simultaneous quantification of seven bioactive markers, namely sophoricoside, baicalin, naringin, genistein, rutin, quercetin and 5-O-methylvisammioside, in HP was performed to interpret the quality consistency. The validation of the proposed approach was acceptable, with the accuracy of 90.2%–106.9% in recovery test. The intra-day and inter-day precisions of the method were evaluated and the RSD values were less than 2.81%. The results from the quantitative data showed that the contents of six marker compounds (except for 5-O-methylvisammioside were quite consistent between batches produced by one manufacturer and significantly distinctive among different manufacturers. The proposed approach was expected to be developed as a powerful tool for the quality control of HP.

  14. Simultaneous Determination of Hydroquinone, Catechol and Resorcinol at Graphene Doped Carbon Ionic Liquid Electrode

    Directory of Open Access Journals (Sweden)

    Li Ma

    2012-01-01

    Full Text Available A new composite electrode has been prepared with doping graphene into the paste consisting graphite and ionic liquid, n-octyl-pyridinum hexafluorophosphate (OPFP. This electrode shows an excellent electrochemical activity for the redox of hydroquinone (HQ, catechol (CC, and resorcinol (RS. In comparison with bare paste electrode, the redox peaks of three isomers of dihydroxybenzene can be obviously, simultaneously observed at graphene doping paste electrode. Under the optimized condition, the simultaneous determination of HQ, CC, and RS in their ternary mixture can be carried out with a differential pulse voltammetric technique. The peak currents are linear to the concentration of HQ, CC, and RS in the range form 1×10−5 to 4×10−4, 1×10−5 to 3×10−4, and 1×10−6 to 1.7×10−4 mol L−1, respectively. The limits of detection are 1.8×10−6 mol L−1 for HQ, 7.4×10−7 mol L−1 for CC, and 3.6×10−7 M for RS, respectively.

  15. A rapid simultaneous determination of methylxanthines and proanthocyanidins in Brazilian guaraná (Paullinia cupana Kunth.).

    Science.gov (United States)

    Machado, Kamilla Nunes; Freitas, Aline Alves de; Cunha, Luzia Helena; Faraco, André Augusto Gomes; Pádua, Rodrigo Maia de; Braga, Fernão Castro; Vianna-Soares, Cristina Duarte; Castilho, Rachel Oliveira

    2018-01-15

    Paullinia cupana is a plant native to Brazil that is widely used in traditional medicine as a physical and mental stimulant. It is also used worldwide to produce soft drinks. A method for the simultaneous quantitation of seven markers in guaraná by HPLC-PDA was developed, and extraction methods for the determination of methylxanthines and tannins were investigated. Quantified substances were theobromine, theophylline, caffeine, catechin, epicatechin, procyanidins A2 and B2. Results confirmed the satisfactory selectivity and linearity (r 2 ≥0.99) within the mass ranges. Repeatability (RSD≤2.80%), intermediate precision (RSD≤4.47%), accuracy (recoveries from 90.59%-104.67%), and robustness were demonstrated. Extract 1 presented the contents: 0.0177% (±1.02%) for theobromine, 0.0131% (±1.14%) for theophylline, 2.9429% (±1.27%) for caffeine, 0.4563% (±1.02%) for catechin, 0.5515% (±1.05%) for epicatechin, 0.0607% (±2.80%) for A2 and 0.1035% (±1.39%) for B2. The method for simultaneous quantitation of seven chemical markers in guaraná proved to be reliable using a simple and convenient HPLC setup. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Simultaneous Determination of Four Anthraquinones in Polygoni Multiflori Radix with Single Reference Standard by High Performance Liquid Chromatography

    Directory of Open Access Journals (Sweden)

    Hua Yang

    2015-07-01

    Full Text Available Objective: To establish a rapid, accurate and reliable analytical method for the simultaneous determination of four major anthraquinones in Polygoni Multiflori Radix (PMR using single reference standard.

  17. Simultaneous Determination of 6-Mercaptopurine and its Oxidative Metabolites in Synthetic Solutions and Human Plasma using Spectrophotometric Multivariate Calibration Methods

    Directory of Open Access Journals (Sweden)

    Mohammad-Reza Rashidi

    2011-06-01

    Full Text Available Introduction: 6-Mercaptopurine (6MP is an important chemotherapeutic drug in the conventional treatment of childhood acute lymphoblastic leukemia (ALL. It is catabolized to 6-thiouric acid (6TUA through 8-hydroxo-6-mercaptopurine (8OH6MP or 6-thioxanthine (6TX intermediates. Methods: High-performance liquid chromatography (HPLC is usually used to determine the contents of therapeutic drugs, metabolites and other important biomedical analytes in biological samples. In the present study, the multivariate calibration methods, partial least squares (PLS-1 and principle component regression (PCR have been developed and validated for the simultaneous determination of 6MP and its oxidative metabolites (6TUA, 8OH6MP and 6TX without analyte separation in spiked human plasma. Mixtures of 6MP, 8-8OH6MP, 6TX and 6TUA have been resolved by PLS-1 and PCR to their UV spectra. Results: Recoveries (% obtained for 6MP, 8-8OH6MP, 6TX and 6TUA were 94.5-97.5, 96.6-103.3, 95.1-96.9 and 93.4-95.8, respectively, using PLS-1 and 96.7-101.3, 96.2-98.8, 95.8-103.3 and 94.3-106.1, respectively, using PCR. The NAS (Net analyte signal concept was used to calculate multivariate analytical figures of merit such as limit of detection (LOD, selectivity and sensitivity. The limit of detections for 6MP, 8-8OH6MP, 6TX and 6TUA were calculated to be 0.734, 0.439, 0.797 and 0.482 µmol L-1, respectively, using PLS and 0.724, 0.418, 0783 and 0.535 µmol L-1, respectively, using PCR. HPLC was also applied as a validation method for simultaneous determination of these thiopurines in the synthetic solutions and human plasma. Conclusion: Combination of spectroscopic techniques and chemometric methods (PLS and PCR has provided a simple but powerful method for simultaneous analysis of multicomponent mixtures.

  18. The application of the inductively coupled plasma system to the simultaneous determination of precious metals

    International Nuclear Information System (INIS)

    Watson, A.E.; Russell, G.M.; Middleton, H.R.; Davenport, F.F.

    1983-01-01

    This report describes the development of a spectrochemical technique using excitation by an inducticely coupled plasma (ICP) source for the simultaneous determination of the precious metals (defined here as gold, silver, and all the platinum-group metals except osmium) in a wide variety of samples from a plant for the extraction and refining of platinum metal. The limits of detection for the analytes were determined in various acid and salt media and, under the conditions used, ranged from 20 to 100ng/l. The analytes were determined in the presence of a thousandfold excess of each of the other precious metals used as a matrix element. Some severe interferences were noted but were ascribed to spectral-line overlap or to contamination of the matrix material. Various dissolution techniques, based upon standard procedures applied in the precious-metals industry, were used, depending on the particular type of material treated. The spectrometer was calibrated by the use of solutions containing the analytes, sodium chloride, and acid, with scandium as the internal standard. The accuracy and precision of the technique, established by the analysis of many samples of each type, were found to be satisfactory when close attention was paid to detail in the preparation of the analytical solution. The relative standard deviation of the method ranges from 0,005 to 0,05, depending on the element being determined

  19. Simultaneous Determination of Four Preservatives in Foodstuffs by High Performance Liquid Chromatography

    Directory of Open Access Journals (Sweden)

    Mohammad Faraji

    2016-04-01

    Full Text Available Background and objectives:  High concentration of preservatives in food may result in gastrointestinal disturbances whereby some patients suffering from asthma, rhinitis, or urticaria. The aim of this study is the introduction and optimization a new method for simultaneous determination of four preservatives (SB, PS, MP, PP in foodstuff by high performance liquid chromatography. Materials and methods: Important factors in extraction, separation and determination process were optimized using the one variable at a time method.  Figures of merit of the proposed method were evaluated. The amount of SB, PS, MP, PP in some food samples were determined using the proposed method. Result: The results showed that the obtained chromatogram of extract was free of significant interferences. The preservatives recoveries ranged from 88% to 110 %. Concentration of SB, PS, MP and PP in the 20studied samples ranges between N.D-639.9, N.D -214.5, N.D -579.8 and N.D -30.5 mg kg-1, respectively  Conclusion: The performance and reliability of proposed method as a simple, efficient and fast method for determination of SB, PS, MP, PP in the food samples was demonstrated.

  20. Simultaneous determination of free amino acids in Pu-erh tea and their changes during fermentation.

    Science.gov (United States)

    Zhu, Yuchen; Luo, Yinghua; Wang, Pengpu; Zhao, Mengyao; Li, Lei; Hu, Xiaosong; Chen, Fang

    2016-03-01

    Pu-erh ripened tea is produced through a unique microbial fermentation process from the sun-dried leaves of large-leaf tea species (Camellia sinensis (Linn.) var. assamica (Masters) Kitamura) in Yunnan province of China. In this study, the changes of amino acid profiles during fermentation of Pu-erh tea were investigated, based on the improved HPLC-UV method with PITC pre-column derivatization for the simultaneous determination of twenty free amino acids. Results showed that aspartic acid, glutamic acid, arginine, alanine, theanine and tyrosine were the major amino acids in tea samples. Fermentation significantly influenced on the amino acid profiles. The total free amino acid contents significantly decreased during fermentation (pfermentation and then decreased gradually. The results provided the useful information for the manipulation of fermentation process according to the changes of amino acids and acrylamide contents in Pu-erh ripened tea. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. Simultaneous determination of dissolved elements in water using ICP-oa-TOFMS

    International Nuclear Information System (INIS)

    Dragomir, M.; Ohai, D.; Dumitrescu, I.; Furtuna, I.

    2008-01-01

    The aim of the paper is devoted to the development of a strategy that permits determination of trace elements in water, using inductively coupled plasma orthogonal acceleration time-of-flight mass spectrometer (Optimass 8000, ICP-oa-TOFMS). The instrument used, the Optimass 8000, allows simultaneous acquisition of the almost entire mass range from the light ions to the heavy ions and also allows to the user to find the possible contaminants and elements previously not considered in real time. The instrument has been successfully used to analyze fifty-seven dissolved elements in water samples: aluminum, antimony, arsenic, barium, beryllium, bismuth, boron, cadmium, calcium, cerium, cesium, chromium, cobalt, copper, dysprosium, erbium, gallium, gadolinium, germanium, hafnium, holmium, indium, iron, lanthanum, lead, lithium, magnesium, manganese, mercury, molybdenum, neodymium, nickel, neodymium, platinum, potassium, praseodymium, rubidium, rhodium, samarium, scandium, selenium, silicon, silver, sodium, strontium, tantalum, tellurium, thallium, tin, titanium, thulium, uranium, vanadium, ytterbium, zinc and zirconium. (authors)

  2. Development of the kits for RIA simultaneous determination of polypeptide hormones

    International Nuclear Information System (INIS)

    Szybinski, Z.

    1982-12-01

    A simple and universal modification of chloramine T technique has been developed for the radioactive iodination of several polypeptide hormones such as insulin, human growth hormone (HGH), human TSH, synthetic human gastrin and beta-endorphine. The prepared products proved to have good immunoreactivity suitable for RIA purposes. The technique is inexpensive and quick. A new procedure has also been worked out utilizing horse myeloperoxidase in solid state as catalyser. The hormones iodinated with this technique show better parameters (e.g. longer stability, better binding to antibody, more favourable adsorption on dextran-coated charcoal); however the specific activities achieved were lower. The possibilities of simultaneous measurement of insulin and HGH have been studied. In this connection, a comparatively simple method for the determination of the endogenous anti-insulin antibodies was developed and used for the control of patients with diabetes and for the checking of new insulin preparations. However, the technique requires relatively sophisticated equipment and computerized calculations

  3. Rapid HPLC-MS method for the simultaneous determination of tea catechins and folates.

    Science.gov (United States)

    Araya-Farias, Monica; Gaudreau, Alain; Rozoy, Elodie; Bazinet, Laurent

    2014-05-14

    An effective and rapid HPLC-MS method for the simultaneous separation of the eight most abundant tea catechins, gallic acid, and caffeine was developed. These compounds were rapidly separated within 9 min by a linear gradient elution using a Zorbax SB-C18 packed with sub 2 μm particles. This methodology did not require preparative and semipreparative HPLC steps. In fact, diluted tea samples can be easily analyzed using HPLC-MS as described in this study. The use of mass spectrometry detection for quantification of catechins ensured a higher specificity of the method. The percent relative standard deviation was generally lower than 4 and 7% for most of the compounds tested in tea drinks and tea extracts, respectively. Furthermore, the method provided excellent resolution for folate determination alone or in combination with catechins. To date, no HPLC method able to discriminate catechins and folates in a quick analysis has been reported in the literature.

  4. UV Spectrophotometric Simultaneous Determination of Paracetamol and Ibuprofen in Combined Tablets by Derivative and Wavelet Transforms

    Science.gov (United States)

    Hoang, Vu Dang; Ly, Dong Thi Ha; Tho, Nguyen Huu; Minh Thi Nguyen, Hue

    2014-01-01

    The application of first-order derivative and wavelet transforms to UV spectra and ratio spectra was proposed for the simultaneous determination of ibuprofen and paracetamol in their combined tablets. A new hybrid approach on the combined use of first-order derivative and wavelet transforms to spectra was also discussed. In this application, DWT (sym6 and haar), CWT (mexh), and FWT were optimized to give the highest spectral recoveries. Calibration graphs in the linear concentration ranges of ibuprofen (12–32 mg/L) and paracetamol (20–40 mg/L) were obtained by measuring the amplitudes of the transformed signals. Our proposed spectrophotometric methods were statistically compared to HPLC in terms of precision and accuracy. PMID:24949492

  5. Simultaneous determination of devolatilization and char burnout times during fluidized bed combustion of coal

    International Nuclear Information System (INIS)

    Christofiedes, N.; Brown, R.C.

    1992-01-01

    In this paper, the authors investigate a method for simultaneous determination of devolatilization and char burnout times based on the analysis of CO 2 emissions from a fluidized bed combustor. The technique is non-intrusive and can be performed under realistic combustion conditions. The authors' method involves batching single-size coal samples in a fluidized bed combustor that is heated with propane gas or other fuel. Carbon dioxide profiles versus time for the batch tests are analyzed with a linear model to obtain characteristic time constants for coal devolatilization and char combustion which can be related to total devolatilization time and burnout time for a coal sample. The authors' approach does not require special sample preparation, can be performed in actual combustion equipment and employs standard boiler instrumentation

  6. Resonant tunneling: A method for simultaneous determination of resonance energy and energy eigenvalue

    Energy Technology Data Exchange (ETDEWEB)

    Maiz, F., E-mail: Fethi_maiz@yahoo.fr [King Khalid University, Faculty of Science, Physics Department, P.O. Box 9004, Abha (Saudi Arabia); University of Cartage, Nabeul Engineering Preparatory Institute, Merazka, 8000 Nabeul (Tunisia); Eissa, S.A. [King Khalid University, Faculty of Science, Physics Department, P.O. Box 9004, Abha (Saudi Arabia); AL-AZHAR University, Faculty of Science, Physics Department, Nasr City, Cairo (Egypt); AlFaify, S. [King Khalid University, Faculty of Science, Physics Department, P.O. Box 9004, Abha (Saudi Arabia)

    2013-09-15

    Assuming an effective mass approximation and using Bastard's boundary conditions, a simple method for simultaneous determination of the energy levels forming the sub-band structure and the transmissions coefficient of non-symmetrical, non-periodical potential semiconducting heterostructure is being proposed. The method can be applied on a multilayer system with varying thickness and effective mass of the layers, and with potential that is neither periodical nor symmetrical. To illustrate the feasibility of the proposed method, cases of symmetrical rectangular triple-barrier structure with constant effective mass, multi-barrier semiconductor heterostructure (nine barriers–eight-wells), and monomer height barrier superlattices (300 barriers) systems have been examined. Findings show very good agreements with previously published results obtained by different methods on similar systems. The proposed method was found to be useful for any number of semiconducting layers arranged in any random way making it more realistic, simple, and applicable to superlattice analysis and for devices design.

  7. Validated spectrophotometric methods for simultaneous determination of Omeprazole, Tinidazole and Doxycycline in their ternary mixture

    Science.gov (United States)

    Lotfy, Hayam M.; Hegazy, Maha A.; Mowaka, Shereen; Mohamed, Ekram Hany

    2016-01-01

    A comparative study of smart spectrophotometric techniques for the simultaneous determination of Omeprazole (OMP), Tinidazole (TIN) and Doxycycline (DOX) without prior separation steps is developed. These techniques consist of several consecutive steps utilizing zero/or ratio/or derivative spectra. The proposed techniques adopt nine simple different methods, namely direct spectrophotometry, dual wavelength, first derivative-zero crossing, amplitude factor, spectrum subtraction, ratio subtraction, derivative ratio-zero crossing, constant center, and successive derivative ratio method. The calibration graphs are linear over the concentration range of 1-20 μg/mL, 5-40 μg/mL and 2-30 μg/mL for OMP, TIN and DOX, respectively. These methods are tested by analyzing synthetic mixtures of the above drugs and successfully applied to commercial pharmaceutical preparation. The methods that are validated according to the ICH guidelines, accuracy, precision, and repeatability, were found to be within the acceptable limits.

  8. Simultaneous determination of some common food dyes in commercial products by digital image analysis

    Directory of Open Access Journals (Sweden)

    Mohammad-Hossein Sorouraddin

    2015-09-01

    Full Text Available A simple and relatively fast image-analysis method using digital images, obtained with a flatbed scanner, has been described. The method was used for the simultaneous determination of four common food dyes, namely, carmoisine, brilliant blue, sunset yellow, and quinoline yellow, in binary mixtures in commercial products without a need for any prior separation steps. The results obtained were validated against a standard high-performance liquid chromatography method and a good agreement was obtained. The parameters affecting the experimental results were optimized. Under the optimal conditions, the method provided acceptable linear ranges (20–250 mg/L with correlation coefficients higher than 0.998, suitable precision (relative standard deviation ≤ 4.5%, and limits of detection between 4.82 and 8.05 mg/L.

  9. Simultaneous Determination of Florfenicol and Diclazuril in Compound Powder by RP-HPLC-UV Method

    Directory of Open Access Journals (Sweden)

    Leilei Guo

    2014-01-01

    Full Text Available A RP-HPLC-UV method was developed and validated for simultaneous determination of florfenicol and diclazuril in compound powder. The separation involved using a SinoChoom ODS-BP C18 (5 μm, 4.6 mm × 250 mm analytical column. The mobile phase was a mixture of acetonitrile-0.2% phosphoric acid (pH was adjusted to 3.0 with triethylamine. The ratio of acetonitrile and 0.2% phosphoric acid in the mobile phase was 60 : 40 (v/v from 0 minutes to 6 minutes and 70 : 30 (v/v from 6.1 minutes to 15 minutes. The flow rate was 1 mL/min. The temperature of the analytical column was maintained at 30°C. The detection was monitored at 225 nm and 277 nm for florfenicol and diclazuril, respectively. The excipients in the compound powder did not interfere with the drug peaks. The calibration curves of florfenicol and diclazuril were fairly linear over the concentration ranges between 50.0–500.0 μg/mL (r=0.9995 and 10.0–100.0 μg/mL (r=0.9992, respectively. The RSD of both the intraday and interday variations was below 2.1% for florfenicol and diclazuril. The method was successfully validated according to International Conference on Harmonisation and proved to be suitable for the simultaneous determination of florfenicol and diclazuril in compound powder.

  10. Novel spectrophotometric methods for simultaneous determination of Amlodipine, Valsartan and Hydrochlorothiazide in their ternary mixture

    Science.gov (United States)

    Lotfy, Hayam M.; Hegazy, Maha A.; Mowaka, Shereen; Mohamed, Ekram Hany

    2015-04-01

    This work represents a comparative study of two smart spectrophotometric techniques namely; successive resolution and progressive resolution for the simultaneous determination of ternary mixtures of Amlodipine (AML), Hydrochlorothiazide (HCT) and Valsartan (VAL) without prior separation steps. These techniques consist of several consecutive steps utilizing zero and/or ratio and/or derivative spectra. By applying successive spectrum subtraction coupled with constant multiplication method, the proposed drugs were obtained in their zero order absorption spectra and determined at their maxima 237.6 nm, 270.5 nm and 250 nm for AML, HCT and VAL, respectively; while by applying successive derivative subtraction they were obtained in their first derivative spectra and determined at P230.8-246, P261.4-278.2, P233.7-246.8 for AML, HCT and VAL respectively. While in the progressive resolution, the concentrations of the components were determined progressively from the same zero order absorption spectrum using absorbance subtraction coupled with absorptivity factor methods or from the same ratio spectrum using only one divisor via amplitude modulation method can be used for the determination of ternary mixtures using only one divisor where the concentrations of the components are determined progressively. The proposed methods were checked using laboratory-prepared mixtures and were successfully applied for the analysis of pharmaceutical formulation containing the cited drugs. Moreover comparative study between spectrum addition technique as a novel enrichment technique and a well established one namely spiking technique was adopted for the analysis of pharmaceutical formulations containing low concentration of AML. The methods were validated as per ICH guidelines where accuracy, precision and specificity were found to be within their acceptable limits. The results obtained from the proposed methods were statistically compared with the reported one where no significant

  11. Ultrasound-assisted extraction method for the simultaneous determination of emerging contaminants in freshwater sediments.

    Science.gov (United States)

    de Sousa, Diana Nara Ribeiro; Grosseli, Guilherme Martins; Mozeto, Antonio Aparecido; Carneiro, Renato Lajarim; Fadini, Pedro Sergio

    2015-10-01

    Sediments are the fate of several emerging organic contaminants, such as pharmaceuticals, personal care products and hormones, and therefore an important subject in environmental monitoring studies. In the present work, a simple and sensitive method was developed, validated and applied for the simultaneous extraction of atenolol, caffeine, carbamazepine, diclofenac, ibuprofen, naproxen, propranolol, triclosan, estrone, 17-β-estradiol and 17-α-ethinylestradiol using ultrasound-assisted extraction from freshwater sediment samples followed by solid-phase extraction clean-up and liquid chromatography with tandem mass spectrometry detection. The solvent type and extraction pH were evaluated to obtain the highest recoveries of the compounds. The best method shows absolute recoveries between 54.0 and 94.4% at 50 ng/g concentration. The method exhibits good precision with relative standard deviation ranging from 1.0-16%. The detection and quantification limits ranged from 0.006-0.067 and 0.016-0.336 ng/g, respectively. The developed method was successfully applied to freshwater sediment samples collected from different sites in Jundiaí River basin of São Paulo State, Brazil. The compounds atenolol, caffeine, propranolol and triclosan were detected in all the sampling sites with concentrations of 13.8, 41.0, 28.5 and 176 ng/g, respectively. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Simultaneous HPLC determination of caffeine, theobromine, and theophylline in food, drinks, and herbal products.

    Science.gov (United States)

    Srdjenovic, Branislava; Djordjevic-Milic, Vukosava; Grujic, Nevena; Injac, Rade; Lepojevic, Zika

    2008-02-01

    A rapid and selective high-performance liquid chromatographic (HPLC) method is developed for the separation and determination of caffeine, theobromine, and theophylline. The chromatography is performed on a Zorbax Eclipse XDB-C8 column (4.6x150 mm i.d., 5-microm particle size) at 25 degrees C, with a mobile phase of water-THF (0.1% THF in water, pH 8)-acetonitrile (90:10, v/v). The flow rate is 0.8 mL/min, and detection is by UV at 273 nm. This method permits the simultaneous determination of caffeine, theobromine, and theophylline in food, drinks, and herbal products with detection limits of 0.07-0.2 mg/L and recoveries of 100.20-100.42%. Correlation coefficients, for the calibration curves in the linear range of 0.2-100 mg/L, are greater than 0.9999 for all compounds. The within- and between-day precision is determined for both retention times and peak area. The data suggests that the proposed HPLC method can be used for routine quality control of food, drinks, and herbal products.

  13. Sequential Spectrophotometric Method for the Simultaneous Determination of Amlodipine, Valsartan, and Hydrochlorothiazide in Coformulated Tablets

    Directory of Open Access Journals (Sweden)

    Hany W. Darwish

    2013-01-01

    Full Text Available A new, simple and specific spectrophotometric method was developed and validated in accordance with ICH guidelines for the simultaneous estimation of Amlodipine (AML, Valsartan (VAL, and Hydrochlorothiazide (HCT in their ternary mixture. In this method three techniques were used, namely, direct spectrophotometry, ratio subtraction, and isoabsorptive point. Amlodipine (AML was first determined by direct spectrophotometry and then ratio subtraction was applied to remove the AML spectrum from the mixture spectrum. Hydrochlorothiazide (HCT could then be determined directly without interference from Valsartan (VAL which could be determined using the isoabsorptive point theory. The calibration curve is linear over the concentration ranges of 4–32, 4–44 and 6–20 μg/mL for AML, VAL, and HCT, respectively. This method was tested by analyzing synthetic mixtures of the above drugs and was successfully applied to commercial pharmaceutical preparation of the drugs, where the standard deviation is <2 in the assay of raw materials and tablets. The method was validated according to the ICH guidelines and accuracy, precision, repeatability, and robustness were found to be within the acceptable limits.

  14. Rapidly Simultaneous Determination of Six Effective Components in Cistanche tubulosa by Near Infrared Spectroscopy

    Directory of Open Access Journals (Sweden)

    Xinhong Wang

    2017-05-01

    Full Text Available Quantitative determination of multiple effective components in a given plant usually requires a very large amount of authentic natural products. In this study, we proposed a rapid and non-destructive method for the simultaneous determination of echinacoside, verbascoside, mannitol, sucrose, glucose and fructose in Cistanche tubulosa by near infrared spectroscopy (NIRS. Near infrared diffuse reflectance spectroscopy (DRS and high performance liquid chromatography (HPLC were conducted on 116 batches of C. tubulosa samples. The DRS data were processed using standard normal variety (SNV and multiplicative scatter correction (MSC methods. Partial least squares regression (PLSR was utilized to build calibration models for components-of-interest in C. tubulosa. All models were then assessed by calculating the root mean square error of calibration (RMSEC, correlation coefficient of calibration (r. The r values of all six calibration models were determined to be greater than 0.94, suggesting each model is reliable. Therefore, the quantitative NIR models reported in this study can be qualified to accurately quantify the contents of six medicinal components in C. tubulosa.

  15. Validated Spectrophotometric Methods for Simultaneous Determination of Food Colorants and Sweeteners

    Directory of Open Access Journals (Sweden)

    Fatma Turak

    2013-01-01

    Full Text Available Two simple spectrophotometric methods have been proposed for simultaneous determination of two colorants (Indigotin and Brilliant Blue and two sweeteners (Acesulfame-K and Aspartame in synthetic mixtures and chewing gums without any prior separation or purification. The first method, derivative spectrophotometry (ZCDS, is based on recording the first derivative curves (for Indigotin, Brillant Blue, and Acesulfame-K and third-derivative curve (for Aspartame and determining each component using the zero-crossing technique. The other method, ratio derivative spectrophotometry (RDS, depends on application ratio spectra of first- and third-derivative spectrophotometry to resolve the interference due to spectral overlapping. Both colorants and sweeteners showed good linearity, with regression coefficients of 0.9992–0.9999. The LOD and LOQ values ranged from 0.05 to 0.33 μgmL−1 and from 0.06 to 0.47 μgmL−1, respectively. The intraday and interday precision tests produced good RSD% values (<0.81%; recoveries ranged from 99.78% to 100.67% for all two methods. The accuracy and precision of the methods have been determined, and the methods have been validated by analyzing synthetic mixtures containing colorants and sweeteners. Two methods were applied for the above combination, and satisfactory results were obtained. The results obtained by applying the ZCDS method were statistically compared with those obtained by the RDS method.

  16. Simultaneous quantitative determination of paracetamol and tramadol in tablet formulation using UV spectrophotometry and chemometric methods

    Science.gov (United States)

    Glavanović, Siniša; Glavanović, Marija; Tomišić, Vladislav

    2016-03-01

    The UV spectrophotometric methods for simultaneous quantitative determination of paracetamol and tramadol in paracetamol-tramadol tablets were developed. The spectrophotometric data obtained were processed by means of partial least squares (PLS) and genetic algorithm coupled with PLS (GA-PLS) methods in order to determine the content of active substances in the tablets. The results gained by chemometric processing of the spectroscopic data were statistically compared with those obtained by means of validated ultra-high performance liquid chromatographic (UHPLC) method. The accuracy and precision of data obtained by the developed chemometric models were verified by analysing the synthetic mixture of drugs, and by calculating recovery as well as relative standard error (RSE). A statistically good agreement was found between the amounts of paracetamol determined using PLS and GA-PLS algorithms, and that obtained by UHPLC analysis, whereas for tramadol GA-PLS results were proven to be more reliable compared to those of PLS. The simplest and the most accurate and precise models were constructed by using the PLS method for paracetamol (mean recovery 99.5%, RSE 0.89%) and the GA-PLS method for tramadol (mean recovery 99.4%, RSE 1.69%).

  17. [Simultaneous determination of madecassoside, asiaticoside and their aglycones in Centella asiatica (L.) urban extracts by RP-HPLC].

    Science.gov (United States)

    Shen, Qian; Yu, Lu-shan; Zhou, Hui; Zeng, Su

    2014-03-01

    To establish a HPLC method for simultaneous determination of four major constituents (madecassoside, asiaticoside, madecassic acid and asiatic acid) in Centella asiatica (L.) urban extracts. The analysis was performed on an Agilent 1100 HPLC system with a ZORBAX Eclipse XDB-C8 column (4.6 mm×150 mm, 5μm). The four major constituents were separated with gradient mobile phase that consists of 1mmol/L potassium dihydrogen phosphate and acetonitrile at the detection wavelength of 205 nm. The four major constituents all had good linear response in the determination ranges (R(2)≥0.9998). The average recoveries (n=9) were 97.4%, 93.7%, 97.5% and 99.8% with RSDs of 3.4%, 1.4%, 4.7% and 4.4%, respectively. The developed method is sensitive and has good reproducibility, which can be used as a reference for quality control of Centella asiatica (L.) urban extracts.

  18. Simultaneous determination of some artificial sweeteners in ternary formulations by FT-IR and EI-MS

    Science.gov (United States)

    Tosa, Nicoleta; Moldovan, Zaharie; Bratu, Ioan

    2012-02-01

    Artificial sweeteners are widely used in food, beverage and pharmaceutical industries all over the world. In this study some non-nutritive sweeteners such as aspartame, acesulfame-K, sodium cyclamate and sodium saccharin were simultaneously determined in ternary mixtures using FT-IR and EI-MS measurements. FT-IR method is based on direct measurements of the peak height values and area centered on 1736 cm-1, 836 cm-1, 2854 cm-1 and 1050 cm-1 for aspartame, acesulfame-K, sodium cyclamate and sodium saccharin, respectively. Mass spectrometry determinations show the characteristic peaks at m/z 91 and 262 for aspartame,m/z 43 and 163 acesulfame-K,m/z 83 and 97 for sodium cyclamate andm/z 104 and 183 for sodium saccharin. The results obtained by EI-MS in different formulations are in agreement with the FT-IR ones and provide also essential data concerning the purity grade of the components. It is concluded that FT-IR and EI-MS procedures developed in this work represent a fast, sensitive and low cost alternative in the quality control of such sweeteners in different ternary formulations.

  19. Second-derivative synchronous fluorescence spectroscopy for the simultaneous determination of naproxen and salicylic acid in human serum.

    Science.gov (United States)

    Konstantianos, D G; Ioannou, P C

    1996-07-01

    Second-derivative synchronous fluorescence spectrometry was used to develop a simple, rapid and sensitive spectrofluorimetric method for the simultaneous determination of naproxen and salicylic acid in human serum. The method is based on the intrinsic fluorescence of naproxen and salicylic acid in chloroform-1% acetic acid solution. A delta gamma of 130 nm was used for the direct measurement of salicylic acid in the binary mixture, whereas naproxen was determined from direct measurements at delta gamma = 60 nm and by means of a correction equation which incorporates the concentration of salicylic acid. The range of application is 0-14 mg l-1 for naproxen and 0-13 mg l-1 for salicylic acid. The detection limits for naproxen and salicylic acid are 0.003 and 0.01 mg l-1, respectively. Serum samples are extracted into chloroform-1% acetic acid solution prior to instrumental measurement. Analytical recoveries range from 97 to 105% (mean 102%) for naproxen and from 97 to 112% (mean 103%) for salicylic acid. The within-run precision (RSD) for the method for four naproxen-salicylic acid mixtures varied from 1.2 to 6.7% and the day-to-day precision for mixtures varied from 2.1 to 5.0%.

  20. Sensitizing Future Health Professionals to Determinants of Childhood Obesity.

    Science.gov (United States)

    Rosemond, Tiara N; Blake, Christine E; Buff, Scotty M; Blake, Elizabeth W; Dunn, Brianne L; Browne, Teri; Bell, Bethany A; Iachini, Aidyn L

    2016-07-01

    Long-term solutions to the childhood obesity epidemic will require concerted interdisciplinary efforts that are sensitive to both individual and social determinants of health. The Junior Doctors of Health© (JDOH) program involves interprofessional education (IPE) with university students from health science fields (e.g., medicine, pharmacy, social work, public health) who deliver an interactive program in teams to at-risk school-aged youth. The purpose of this study was to assess the impact of participation in the JDOH IPE program on university students' beliefs about childhood obesity. Fifty-three of the 71 health sciences students enrolled in the JDOH IPE program between 2011 and 2013 participated in this study. Pre- and post-surveys assessed students' beliefs about the importance, causes of, and responsibility for reducing childhood obesity with both closed- and open-ended questions. In 2013, quantitative data were analyzed using Wilcoxon matched-pairs signed-rank tests and qualitative data were analyzed through open coding to identify emergent themes. Results indicate that after participation in the JDOH IPE program, students' identification of social and environmental causes of childhood obesity increased significantly. Further, students' ranking of the importance of obesity was initially higher than those of different issues typically portrayed as social or environmental (e.g., youth violence) but it was similarly ranked after participation in JDOH. This suggests a greater sensitivity to social and environmental challenges faced by youth. Findings suggest that IPE experiences that bring clinical and community-oriented health professions together to engage with disadvantaged youth foster sensitivity to the complexities of childhood obesity in low-income settings. Copyright © 2016 American Journal of Preventive Medicine. Published by Elsevier Inc. All rights reserved.

  1. Using nonequilibrium capillary electrophoresis of equilibrium mixtures (NECEEM) for simultaneous determination of concentration and equilibrium constant.

    Science.gov (United States)

    Kanoatov, Mirzo; Galievsky, Victor A; Krylova, Svetlana M; Cherney, Leonid T; Jankowski, Hanna K; Krylov, Sergey N

    2015-03-03

    Nonequilibrium capillary electrophoresis of equilibrium mixtures (NECEEM) is a versatile tool for studying affinity binding. Here we describe a NECEEM-based approach for simultaneous determination of both the equilibrium constant, K(d), and the unknown concentration of a binder that we call a target, T. In essence, NECEEM is used to measure the unbound equilibrium fraction, R, for the binder with a known concentration that we call a ligand, L. The first set of experiments is performed at varying concentrations of T, prepared by serial dilution of the stock solution, but at a constant concentration of L, which is as low as its reliable quantitation allows. The value of R is plotted as a function of the dilution coefficient, and dilution corresponding to R = 0.5 is determined. This dilution of T is used in the second set of experiments in which the concentration of T is fixed but the concentration of L is varied. The experimental dependence of R on the concentration of L is fitted with a function describing their theoretical dependence. Both K(d) and the concentration of T are used as fitting parameters, and their sought values are determined as the ones that generate the best fit. We have fully validated this approach in silico by using computer-simulated NECEEM electropherograms and then applied it to experimental determination of the unknown concentration of MutS protein and K(d) of its interactions with a DNA aptamer. The general approach described here is applicable not only to NECEEM but also to any other method that can determine a fraction of unbound molecules at equilibrium.

  2. A new innovative spectrophotometric method for the simultaneous determination of sofosbuvir and ledipasvir

    Science.gov (United States)

    Mansour, Fotouh R.

    2018-01-01

    A new innovative spectrophotometric method is developed to determine the concentration ratios in binary mixtures by determining the zero crossing point in the first derivative of the gross curve. This relationship can be applied if the part of the UV spectrum of substance Y, that intersects with the overlaid spectra of substance X is straight. By plotting the intersection wavelength against the concentration ratio (Cx/Cy), a straight line was obtained with a co-efficient of determination equals 0.9999. As an application, simultaneous determination of sofosbuvir and ledipasvir in their binary mixtures was performed using two methods; a direct UV spectrophotometric method for determination of ledipasvir at 333 nm, and the new "wavelength-intersection ratio" method for determination of sofosbuvir. In the wavelength-intersection ratio method, different mixtures of sofosbuvir and ledipasvir containing different concentration ratios were prepared; the zero crossing point of the first derivative curve in the range 285 to 295 nm were determined for each mixture. An absorbance shift in the intersection was obtained with the change in the concentration ratio (sofosbuvir/ledipasvir). When the concentration ratio was plotted against the intersection wavelength, a straight line was obtained with a coefficient of determination of 0.9992. The direct method was linear in the range 3 to 18 μg/mL while the wavelength-intersection ratio method was linear in the range 11-110 μg/mL. The limits of detection were determined and found to be 0.5 and 3 μg/mL for ledipasvir and sofosbuvir, respectively. The accuracy and repeatability of the two methods were tested. The mean %recovery was found to be 100.19% and 100.75% for ledipasvir and sofosbuvir, respectively. The relative standard deviation was 0.57 for ledipasvir and 1.79 for sofosbuvir. The intermediate precision was also checked, the coefficients of variation for sofosbuvir and ledipasvir measurements between days did not exceed 1.88%.

  3. Simultaneous single-sample determination of NMNAT isozyme activities in mouse tissues.

    Directory of Open Access Journals (Sweden)

    Giuseppe Orsomando

    Full Text Available A novel assay procedure has been developed to allow simultaneous activity discrimination in crude tissue extracts of the three known mammalian nicotinamide mononucleotide adenylyltransferase (NMNAT, EC 2.7.7.1 isozymes. These enzymes catalyse the same key reaction for NAD biosynthesis in different cellular compartments. The present method has been optimized for NMNAT isozymes derived from Mus musculus, a species often used as a model for NAD-biosynthesis-related physiology and disorders, such as peripheral neuropathies. Suitable assay conditions were initially assessed by exploiting the metal-ion dependence of each isozyme recombinantly expressed in bacteria, and further tested after mixing them in vitro. The variable contributions of the three individual isozymes to total NAD synthesis in the complex mixture was calculated by measuring reaction rates under three selected assay conditions, generating three linear simultaneous equations that can be solved by a substitution matrix calculation. Final assay validation was achieved in a tissue extract by comparing the activity and expression levels of individual isozymes, considering their distinctive catalytic efficiencies. Furthermore, considering the key role played by NMNAT activity in preserving axon integrity and physiological function, this assay procedure was applied to both liver and brain extracts from wild-type and Wallerian degeneration slow (Wld(S mouse. Wld(S is a spontaneous mutation causing overexpression of NMNAT1 as a fusion protein, which protects injured axons through a gain-of-function. The results validate our method as a reliable determination of the contributions of the three isozymes to cellular NAD synthesis in different organelles and tissues, and in mutant animals such as Wld(S.

  4. Dynamic pressure sensitivity determination with Mach number method

    Science.gov (United States)

    Sarraf, Christophe; Damion, Jean-Pierre

    2018-05-01

    Measurements of pressure in fast transient conditions are often performed even if the dynamic characteristic of the transducer are not traceable to international standards. Moreover, the question of a primary standard in dynamic pressure is still open, especially for gaseous applications. The question is to improve dynamic standards in order to respond to expressed industrial needs. In this paper, the method proposed in the EMRP IND09 ‘Dynamic’ project, which can be called the ‘ideal shock tube method’, is compared with the ‘collective standard method’ currently used in the Laboratoire de Métrologie Dynamique (LNE/ENSAM). The input is a step of pressure generated by a shock tube. The transducer is a piezoelectric pressure sensor. With the ‘ideal shock tube method’ the sensitivity of a pressure sensor is first determined dynamically. This method requires a shock tube implemented with piezoelectric shock wave detectors. The measurement of the Mach number in the tube allows an evaluation of the incident pressure amplitude of a step using a theoretical 1D model of the shock tube. Heat transfer, other actual effects and effects of the shock tube imperfections are not taken into account. The amplitude of the pressure step is then used to determine the sensitivity in dynamic conditions. The second method uses a frequency bandwidth comparison to determine pressure at frequencies from quasi-static conditions, traceable to static pressure standards, to higher frequencies (up to 10 kHz). The measurand is also a step of pressure generated by a supposed ideal shock tube or a fast-opening device. The results are provided as a transfer function with an uncertainty budget assigned to a frequency range, also deliverable frequency by frequency. The largest uncertainty in the bandwidth of comparison is used to trace the final pressure step level measured in dynamic conditions, owing that this pressure is not measurable in a steady state on a shock tube. A reference

  5. Simultaneous determination of antiretroviral drugs in human hair with liquid chromatography-electrospray ionization-tandem mass spectrometry.

    Science.gov (United States)

    Wu, Yan; Yang, Jin; Duan, Cailing; Chu, Liuxi; Chen, Shenghuo; Qiao, Shan; Li, Xiaoming; Deng, Huihua

    2018-04-15

    The determination of the concentrations of antiretroviral drugs in hair is believed to be an important means for the assessment of the long-term adherence to highly active antiretroviral therapy. At present, the combination of tenofovir, lamivudine and nevirapine is widely used in China. However, there was no research reporting simultaneous determination of the three drugs in hair. The present study aimed to develop a sensitive method for simultaneous determination of the three drugs in 2-mg and 10-mg natural hair (Method 1 and Method 2). Hair samples were incubated in methanol at 37 °C for 16 h after being rinsed with methanol twice. The analysis was performed on high performance liquid chromatography tandem mass spectrometry with electronic spray ionization in positive mode and multiple reactions monitoring. Method 1 and Method 2 showed the limits of detection at 160 and 30 pg/mg for tenofovir, at 5 and 6 pg/mg for lamivudine and at 15 and 3 pg/mg for nevirapine. The two methods showed good linearity with the square of correlation coefficient >0.99 at the ranges of 416-5000 and 77-5000 pg/mg for tenofovir, 12-5000 and 15-5000 pg/mg for lamivudine and 39-50,000 and 6-50,000 pg/mg for nevirapine. They gave intra-day and inter-day coefficient of variation <15% and the recoveries ranging from 80.6 to 122.3% and from 83.1 to 114.4%. Method 2 showed LOD and LOQ better than Method 1 for tenofovir and nevirapine and matched Method 1 for lamivudine, but there was high consistency between them in the determination of the three drugs in hair. The population analysis with Method 2 revealed that the concentrations in hair were decreased with the distance of hair segment away from the scalp for the three antiretroviral drugs. Copyright © 2018 Elsevier B.V. All rights reserved.

  6. Simultaneous determination of ascorbic acid, dopamine and uric acid based on tryptophan functionalized graphene

    Energy Technology Data Exchange (ETDEWEB)

    Lian, Qianwen; He, Zhifang; He, Qian; Luo, Ai; Yan, Kaiwang; Zhang, Dongxia [Key Laboratory of Bioelectrochemistry and Environmental Analysis of Gansu Province, College of Geography and Environment Science, Northwest Normal University, Lanzhou, 730070 (China); Lu, Xiaoquan, E-mail: Luxq@nwnu.edu.cn [Key Laboratory of Bioelectrochemistry and Environmental Analysis of Gansu Province, College of Chemistry and Chemical Engineering, Northwest Normal University, Lanzhou, 730070 (China); Zhou, Xibin, E-mail: zhouxb@nwnu.edu.cn [Key Laboratory of Bioelectrochemistry and Environmental Analysis of Gansu Province, College of Geography and Environment Science, Northwest Normal University, Lanzhou, 730070 (China)

    2014-05-01

    Highlights: • Trp-GR was synthesized by utilizing a facile ultrasonic method. • The material as prepared had well dispersivity in water and better conductivity than pure GR. • Trp-GR/GCE showed excellent potential for the determination of AA, DA and UA. • The proposed method was applied for the analysis of AA, DA and UA in real samples. - Abstract: A new type of tryptophan-functionalized graphene nanocomposite (Trp-GR) was synthesized by utilizing a facile ultrasonic method via π–π conjugate action between graphene (GR) and tryptophan (Trp) molecule. The material as prepared had well dispersivity in water and better conductivity than pure GR. The surface morphology of Trp-GR was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Raman spectroscopy. The electrochemical behaviors of ascorbic acid (AA), dopamine (DA), and uric acid (UA) were investigated by cyclic voltammetry (CV) on the surface of Trp-GR. The separation of the oxidation peak potentials for AA–DA, DA–UA and UA–AA was about 182 mV, 125 mV and 307 mV, which allowed simultaneously determining AA, DA, and UA. Differential pulse voltammetery (DPV) was used for the determination of AA, DA, and UA in their mixture. Under optimum conditions, the linear response ranges for the determination of AA, DA, and UA were 0.2–12.9 mM, 0.5–110 μM, and 10–1000 μM, with the detection limits (S/N = 3) of 10.09 μM, 0.29 μM and 1.24 μM, respectively. Furthermore, the modified electrode was investigated for real sample analysis.

  7. Norepinephrine-modified glassy carbon electrode for the simultaneous determination of ascorbic acid and uric acid

    International Nuclear Information System (INIS)

    Zare, H.R.; Memarzadeh, F.; Ardakani, M. Mazloum; Namazian, M.; Golabi, S.M.

    2005-01-01

    The oxidation of norepinephrine (NE) on a preactivated glassy carbon electrode leads to the formation of a deposited layer of about 4.2 x 10 -10 mol cm -2 at the surface of the electrode. The electron transfer rate constant, k s , and charge transfer coefficient, α, for electron transfer between the electrode and immobilized NE film were calculated as 44 s -1 and 0.46, respectively. The NE-modified glassy carbon electrode exhibited good electrocatalytic properties towards ascorbic acid (AA) oxidation in phosphate buffer (pH 7.0) with an overpotential of about 475 mV lower than that of the bare electrode. The electrocatalytic response was evaluated by cyclic voltammetry, chronoamperometry, amperometry and rotating disk voltammetry. The overall number of electrons involved in the catalytic oxidation of AA and the number of electrons involved in the rate-determining step are 2 and 1, respectively. The rate constant for the catalytic oxidation of AA was evaluated by RDE voltammetry and an average value of k h was found to be 8.42 x 10 3 M -1 s -1 . Amperometric determination of AA in stirred solution exhibits a linear range of 2.0-1300.0 μM (correlation coefficient 0.9999) and a detection limit of 0.076 μM. The precision of amperometry was found to be 1.9% for replicate determination of a 49.0 μM solution of AA (n = 6). In differential pulse voltammetric measurements, the NE-modified glassy carbon electrode can separate the AA and uric acid (UA) signals. Ascorbic acid oxidizes at more negative potential than UA. Also, the simultaneous determination of UA and AA is achieved at the NE-modified electrode

  8. Simultaneous Determination of Caffeine and Chlorogenic Acids in Green Coffee by UV/Vis Spectroscopy

    Directory of Open Access Journals (Sweden)

    G. Navarra

    2017-01-01

    Full Text Available A simple method for the simultaneous determination of caffeine and chlorogenic acids content in green coffee was reported. The method was based on the use of UV/Vis absorption. It is relevant that the quantification of both caffeine and chlorogenic acids was performed without their preliminary chemical separation despite their spectral overlap in the range 250–350 nm. Green coffee was extracted with 70% ethanol aqueous solution; then the solution was analyzed by spectroscopy. Quantitative determination was obtained analytically through deconvolution of the absorption spectrum and by applying the Lambert-Beer law. The bands used for the deconvolution were the absorption bands of both caffeine and chlorogenic acids standards. The molar extinction coefficients for caffeine and chlorogenic acid in ethanol solution at 70% were calculated by using the chemical standards; the estimated values were ε(272 nm=12159±97 M−1 cm−1 for caffeine and ε(330 nm=27025±190 M−1 cm−1 for chlorogenic acids molecules, respectively. The estimate of concentration values was in agreement with the one obtained by High Performance Liquid Chromatography quantification. The method is fast and simple and allows us to realize routine controls during the coffee production. In addition, it could be applied on roasted coffee and espresso coffee.

  9. An automatic optosensing device for the simultaneous determination of resveratrol and piceid in wines

    Energy Technology Data Exchange (ETDEWEB)

    Molina-Garcia, Lucia; Ruiz-Medina, Antonio [Department of Physical and Analytical Chemistry, University of Jaen, Campus Las Lagunillas s/n, 23071 Jaen (Spain); Fernandez-de Cordova, Maria Luisa, E-mail: mferna@ujaen.es [Department of Physical and Analytical Chemistry, University of Jaen, Campus Las Lagunillas s/n, 23071 Jaen (Spain)

    2011-03-18

    For the first time, a spectrofluorimetric method is reported for the simultaneous determination of resveratrol (RVT) and piceid (PCD), two stilbenes showing diverse interesting physiological and biochemical attributes, as well as a wide range of health benefits ranging from cardioprotection to chemoprevention. The method makes use of a multicommutated flow-through optosensor in which the resolution of RVT and PCD is accomplished by means the sequential arrival of their photoproducts, on-line generated by UV-irradiation, to the detection area. This is possible due to the different kinetic behaviour of these latter on a solid support (C{sub 18} silica gel) filling a minicolumn placed before the detector. The measurement in solid-phase of the photochemically induced fluorescence of the photoproducts ({lambda}{sub ex}: 257 nm/{lambda}{sub em}: 382 nm) is used as analytical signal for monitoring both compounds. The method has been applied to the analysis of RVT and PCD in wines and requires a previous solid-phase extraction (SPE) using Bakerbond C{sub 18} cartridges. This pretreatment and the use of a solid-support in both the minicolumn and the flow-cell of the detector allow the determination of RVT and PCD by external calibration. Detection limits (DLs) are 9.3 and 12.6 ng mL{sup -1} for RVT and PCD, respectively. Commercial red and white wine samples have been analysed and the results obtained have been satisfactorily validated by high-performance liquid chromatography (HPLC).

  10. Simultaneous determination of ten preservatives in ten kinds of foods by micellar electrokinetic chromatography.

    Science.gov (United States)

    Ding, Xiao-Jing; Xie, Na; Zhao, Shan; Wu, Yu-Chen; Li, Jiang; Wang, Zhi

    2015-08-15

    An improved micellar electrokinetic capillary chromatography method (MEKC) for the simultaneous determination of ten preservatives in ten different kinds of food samples was reported. An uncoated fused-silica capillary with 50 μm i.d. and 70 cm total length was used. Under the optimized conditions, the linear response was observed in the range of 1.2-200mg/L for the analytes. The limits of detection (LOD, S/N=3) and limits of quantitation (LOQ, S/N=10) ranging from 0.4 to 0.5mg/L and 1.2 to 1.5mg/L, respectively were obtained. The method was used for the determination of sorbic and benzoic acids in two FAPAS® (Food Analysis Performance Assessment Scheme) proficiency test samples (jam and chocolate cake). The results showed that the current method with simple sample pretreatment and small reagent consumption could meet the needs for routine analysis of the ten preservatives in ten types of food products. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. Simultaneous Determination of Amiloride and Hydrochlorothiazide in a Compound Tablet by Diffuse Reflectance Spectroscopy and Chemometrics

    Science.gov (United States)

    Tang, J.; Li, X.; Feng, Y.; Liang, B.

    2016-09-01

    This paper studies the simultaneous determination of amiloride hydrochloride (AMH) and hydrochlorothiazide (HCTZ) in amiloride hydrochloride tablets by ultraviolet-visible-shortwave near-infrared diffuse reflectance spectroscopy (UV-Vis-swNIR DRS) and chemometrics. Quantitative models for the two components were established by partial least squares (PLS) and support vector regression (SVR), respectively. For the PLS models of AMH and HCTZ, the determination coefficient R2 of the calibration set was 0.9503 and 0.9538, and the coefficient R2 of the prediction set was 0.8983 and 0.9260, respectively. The root mean square error of the calibration set (RMSEC) was 0.8 mg and 8.1 mg, while the root mean square error of the prediction set (RMSEP) was 1.0 mg and 8.7 mg, respectively. For the SVR models of AMH and HCTZ, the R2 of the calibration set was 0.9668 and 0.9609; the R2 of the prediction set was 0.9145 and 0.9446, respectively. The RMSEC was 0.7 and 7.5 mg, and the RMSEP was 0.9 and 8.9 mg, respectively. The results show that SVR modeling has a satisfactory prediction effect. The proposed method based on UV-vis-swNIR and chemometrics is efficient, nondestructive, and expected to be used for online quality monitoring in the production of drugs.

  12. Simultaneous determination of radionuclides separable into natural decay series by use of time-interval analysis

    International Nuclear Information System (INIS)

    Hashimoto, Tetsuo; Sanada, Yukihisa; Uezu, Yasuhiro

    2004-01-01

    A delayed coincidence method, time-interval analysis (TIA), has been applied to successive α-α decay events on the millisecond time-scale. Such decay events are part of the 220 Rn→ 216 Po (T 1/2 145 ms) (Th-series) and 219 Rn→ 215 Po (T 1/2 1.78 ms) (Ac-series). By using TIA in addition to measurement of 226 Ra (U-series) from α-spectrometry by liquid scintillation counting (LSC), two natural decay series could be identified and separated. The TIA detection efficiency was improved by using the pulse-shape discrimination technique (PSD) to reject β-pulses, by solvent extraction of Ra combined with simple chemical separation, and by purging the scintillation solution with dry N 2 gas. The U- and Th-series together with the Ac-series were determined, respectively, from alpha spectra and TIA carried out immediately after Ra-extraction. Using the 221 Fr→ 217 At (T 1/2 32.3 ms) decay process as a tracer, overall yields were estimated from application of TIA to the 225 Ra (Np-decay series) at the time of maximum growth. The present method has proven useful for simultaneous determination of three radioactive decay series in environmental samples. (orig.)

  13. Simultaneous determination of sweeteners in beverages by LC-MS/MS.

    Science.gov (United States)

    Sakai, Hiroaki; Yamashita, Azusa; Tamura, Masayoshi; Uyama, Atsuo; Mochizuki, Naoki

    2015-01-01

    A new method was established for the simultaneous determination of 10 sweeteners and a degradation product in beverages by using LC-MS/MS. An ACQUITY UPLC BEH C18 (2.1 × 100 mm, 1.7 μm) was used as the LC column and 0.1% each of aqueous formic acid and formic acid in acetonitrile were used as the mobile phase. A simple and rapid determination of sweeteners was possible by diluting with a solvent, and in the case of some samples containing a large amount of foreign matter, after pre-treatment by diluting with solvent and clean-up of the sample using an Oasis HLB cartridge. All the validation results were satisfactory. As the regulations and standards for sweeteners vary from country to country, a field survey of 58 beverages marketed in Japan was performed using the present method. No issues concerning the labelling or food sanitation law were found in the tested samples.

  14. Simultaneous RP-HPLC determination of sparfloxacin and dexamethasone in pharmaceutical formulations

    Directory of Open Access Journals (Sweden)

    Syed Naeem Razzaq

    2013-06-01

    Full Text Available The present study describes the development and subsequent validation of simple and accurate stability indicating RP-HPLC method for the determination of sparfloxacin and dexamethasone in pharmaceutical formulations in the presence of their stress-induced degradation products. Both the drugs and their stress-induced degradation products were separated within 10 minutes using C8 column and mixture of methanol and 0.02 M phosphate buffer pH 3.0 (60:40 v/v, respectively as mobile phase at 270 nm using diode array detector. Regression analysis showed linearity in the range of 15-105 µg/mL for sparfloxacin and 5-35 µg/mL for dexamethasone. All the analytes were adequately resolved with acceptable tailing. Peak purity of the two drugs was also greater than 0.9999, showing no co-elution peaks. The developed method was applied for simultaneous determination of sparfloxacin and dexamethasone in pharmaceutical formulations for stability studies.

  15. Microwave assisted direct saponification for the simultaneous determination of cholesterol and cholesterol oxides in shrimp.

    Science.gov (United States)

    Souza, Hugo A L; Mariutti, Lilian R B; Bragagnolo, Neura

    2017-05-01

    A novel microwave-assisted direct saponification method for the simultaneous determination of cholesterol and cholesterol oxides in shrimp was developed and validated. Optimal saponification conditions, determined by means of an experimental design, were achieved using 500mg of sample and 20mL of 1mol/L KOH ethanol solution for 16min at 45°C at maximum power at 200W and magnetic stirring at 120rpm. Higher extraction of cholesterol oxides in a reduced saponification time (∼75 times) was achieved in comparison with the direct cold saponification method. The new method showed low detection (≤0.57μg/mL) and quantification (≤1.73μg/mL) limits, good repeatability (≤10.50% intraday and ≤8.56% interday) and low artifact formation (evaluated by using a deuterated cholesterol-D6 standard). Raw, salted and dried-salted shrimps were successfully analyzed by the validated method. The content of cholesterol oxides increased after salting and decreased after drying. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. Simultaneous extraction and determination of anionic surfactants in waters and sediments.

    Science.gov (United States)

    Lara-Martín, Pablo A; Gómez-Parra, Abelardo; González-Mazo, Eduardo

    2006-05-12

    A new method has been developed for the simultaneous determination of the most frequently used anionic surfactants - linear alkylbenzene sulfonates (LAS), alkyl ethoxysulfates (AES) and alkyl sulfates (AS) - in aqueous and sediment samples. Preconcentration and purification of water samples are carried out by means of solid-phase extraction (SPE). The efficiency of two different extraction methods for the analysis of sediments - Soxhlet extraction and pressurized liquid extraction (PLE) - has been compared. Identification and quantification of the target compounds is performed using a liquid chromatography - mass spectrometry (LC-MS) system equipped with an electrospray interface (ESI) in negative ion-mode. Homologue recoveries are 85-123% for SPE, 94-112% for Soxhlet extraction and 81-125% for PLE in the case of LAS, and 60-94% for SPE, 61-109% for Soxhlet extraction and 55-99% for PLE in the case of AES, whereas the limits of detection are 0.1-0.5 ngml(-1) in water and 1-5 ngg(-1) in sediment. This method has been applied to the determination of anionic surfactants in the Guadalete estuary (SW Spain), and LAS concentration levels from 538 to 1014 ngg(-1) in sediments and from 25.1 to 64.4 ngml(-1) in waters have been found. AES values from 168 to 536 ngg(-1) in sediments and from 4.5 to 11.9 ngml(-1) in waters are reported for the first time in European rivers.

  17. [Simultaneous determination of ten organotin compounds in polyvinyl chloride plastics using gas chromatography-mass spectrometry].

    Science.gov (United States)

    Li, Ying; Li, Bin; Liu, Li; Zhang, Chen; Wu, Jingwu; Liu, Zhihong; Li, Xintian

    2009-01-01

    A rapid and effective gas chromatography coupled with mass spectrometry method has been developed systematically and studied for the simultaneous determination of 10 organotin compounds, dibutyltin-dichloride (DBT), n-butyltin-trichloride (MBT), triethyltinchloride (TET), fentin-chloride (TPhT), chlorotributylstannane (TBT), tri-n-propyltinchloride (TPrT), diphenyltin-dichloride (DPhT), tetrabutyltin (TeBT), di-n-octyltin-dichloride (DOT), phenyltin trichloride (MPhT)), in polyvinyl chloride (PVC) plastics. The PVC sample was dissolved with tetrahydrofuran and the polymer in the sample was precipitated with methanol, and then the target compounds were derivatized with sodium tetraethylborate and extracted with hexane under ultrasonication. The qualitative and quantitative analysis were carried out by GC-MS and the total ion chromatogram and selected ion chromatogram were obtained. The derivatization and extraction conditions, such as the derivatization time, derivatization pH value, dosages of derivatization reagent and precipitation reagent were optimized. The good linearities, recoveries and precisions were obtained. The linearity ranges were 0.5 - 50 mg/L. The linearity correlation coefficients of 10 organotin compounds were between 0.997 8 and 0.999 7. The average recoveries were 84.23% - 109.1% with relative standard deviations of 4.24% - 10.75%. The established method has been successfully applied to the determination of organotin compounds in PVC plastics.

  18. Simultaneous determination of caffeine, theophylline and theobromine in food samples by a kinetic spectrophotometric method.

    Science.gov (United States)

    Xia, Zhenzhen; Ni, Yongnian; Kokot, Serge

    2013-12-15

    A novel kinetic spectrophotometric method was developed for the simultaneous determination of caffeine, theobromine and theophylline in food samples. This method was based on the different kinetic characteristics between the reactions of analytes with cerium sulphate in sulphuric acid and the associated change in absorbance at 320 nm. Experimental conditions, the effects of sulphuric acid, cerium sulphate and temperature, were optimised. Linear ranges (0.4-8.4 μg mL(-1)) for all three analytes were established, and the limits of detection were: 0.30 μg mL(-1) (caffeine), 0.33 μg mL(-1) (theobromine) and 0.16 μg mL(-1) (theophylline). The recorded data were processed by partial least squares and artificial neural network, and the developed mathematical models were then used for prediction. The proposed, novel method was applied to determine the analytes in commercial food samples, and there were no significant differences between the results from the proposed method and those obtained by high-performance liquid chromatography. Copyright © 2013 Elsevier Ltd. All rights reserved.

  19. [Simultaneous determination of twenty-one organic acids in food by ion chromatography with eluent autogeneration].

    Science.gov (United States)

    Lin, Huaying; Lin, Fenghua; Sheng, Lina; Li, Yidan; Zhang, Qiong

    2007-01-01

    A novel ion chromatographic method was developed for the simultaneous determination of organic acids in food samples including quinic acid, acetic acid, pyruvic acid, ketosuccinic acid, mannitic acid, lactic acid, succinic acid, malic acid, tartaric acid, oxalic acid, fumaric acid, ascorbic acid, alpha-ketoglutaric acid, cinnamic acid, salicylic acid, citric acid, isocitric acid, ferulic acid, cis-aconitic acid, trans-aconitic acid, beta-coumaric acid. 5 - 34 mmol/L KOH produced by an EG40 eluent autogenerator could achieve a flat baseline and lower background conductance when performing gradient elution. The flow rate was 0.6 - 2.5 mL/min and the injection volume was 25 microL. The separation was performed on an IonPac AS11 column and detected by suppressed conductivity with self-regenerating suppressor mode. The samples were prepared through extraction, decoloration and filtration before analysis. Twenty-one organic acids showed good linear relationship between the mass concentration and the peak area in the measurement ranges. The correlation coefficients were above 0.999 and the detection limits were 0.011 - 0.188 mg/L, and the average recoveries were 91.5% - 101.8%. The method is simple and rapid with good accuracy and reproducibility, and has been applied to determine twenty-one organic acids in diversiform samples with satisfactory results.

  20. Multiwall carbon nanotube modified glassy carbon electrode as voltammetric sensor for the simultaneous determination of ascorbic acid and caffeine

    International Nuclear Information System (INIS)

    Gupta, Vinod Kumar; Jain, Ajay Kumar; Shoora, Sudhir Kumar

    2013-01-01

    Highlights: ► Performance of bare and modified GCE for the study of oxidation of drugs. ► MWCNT/MGCE used for determination of AA and CAF in various samples. ► It is demonstrated that the modified electrode is better than the bare GCE. ► AA and CAF are quantified in tea leaves, coffee, cold drink, urine samples. - Abstract: Simultaneous determination of ascorbic acid (AA) and caffeine (CAF) in pharmaceutical preparation is important and it has been achieved by square wave voltammetry (SWV) using a glassy carbon electrode (GCE) modified with multiwall carbon nanotubes (MWCNT). The oxidation of AA and CAF at MWCNT occurred at ∼−10 mV and ∼1103 mV at a much lower potential, than that observed (∼202 mV and ∼1402 mV) for their oxidation at bare GCE. The mechanistic study has shown that the equal number of electrons and protons are involved in the oxidation of drugs. The electrodes could be used for the determination of AA and CAF in a wide concentration range 10–500 μM, respectively, whereas the detection limit has been found to be 1.0 × 10 −2 μM and 3.52 × 10 −3 μM respectively. In view of high sensitivity for the detection of the drugs, the technique has been used for the reliable determination of AA and CAF in tea leaves, coffee, cold drink (mountain dew), pharmaceutical preparations and urine samples

  1. A simultaneous multiple species acute toxicity test comparing relative sensitivities of six aquatic organisms to HgCl{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    McCrary, J.E.; Heagler, M.G. [McNeese State Univ., Lake Charles, LA (United States). Dept. of Biological and Environmental Science

    1995-12-31

    In the last few years there has been concern in the scientific community about observed declines in some amphibian species. These population declines could be reflecting a global phenomenon due to a general class sensitivity or may be part of a natural cycle. The suggestion of an overall greater sensitivity of amphibians is not supported. Studies show that amphibians, as a class, are neither more or less susceptible than fish to environmental conditions. Mercury has been found to be one of the most toxic of the heavy metals introduced into amphibian breeding waters. Six aquatic species were simultaneously exposed in a comparative acute toxicity test with mercury chloride: three amphibians, Rana catesbeiana (bullfrog), R. clamitans (green frog), and R. sphenocephala (southern leopard frog, formally classified as R. utricularia); two fish, Gambusia affinis (mosquitofish) and Notemigonus crysoleucas (golden shiner); one aquatic aligochaete, Lumbriculus variegatus (aquatic earthworm). The five test concentrations used were 1.4, 3.9, 12.0, 110.0, and 487.0 {micro}g Hg/L respectively. Ten organisms per species were randomly placed into the six test tanks (control and five concentrations), each species in a separate chamber. The resultant LC50-96hr values produced the following rank order: R. sphenocephala, 6.59 {micro}g Hg/L; R. clamitans, 14.7 {micro}g Hg/L; N. crysoleucas, 16.75 {micro}g Hg/L; L. variegatus, 43.72,ug Hg/L; G. affinis, 52.62 {micro}g Hg/L; R. catesbeiana, 63.36 {micro}g Hg/L. No general organism class sensitivity trend, for amphibians, was developed from this data, contrary to the implicit suggestions of some researchers.

  2. Determination of kinetic coefficients for the simultaneous reduction of sulfate and uranium by Desulfovibrio desulfuricans bacteria

    International Nuclear Information System (INIS)

    Tucker, M.D.

    1995-05-01

    Uranium contamination of groundwaters and surface waters near abandoned mill tailings piles is a serious concern in many areas of the western United States. Uranium usually exists in either the U(IV) or the U(VI) oxidation state. U(VI) is soluble in water and, as a result, is very mobile in the environment. U(IV), however, is generally insoluble in water and, therefore, is not subject to aqueous transport. In recent years, researchers have discovered that certain anaerobic microorganisms, such as the sulfate-reducing bacteria Desulfovibrio desulfuricans, can mediate the reduction of U(VI) to U(IV). Although the ability of this microorganism to reduce U(VI) has been studied in some detail by previous researchers, the kinetics of the reactions have not been characterized. The purpose of this research was to perform kinetic studies on Desulfovibrio desulficans bacteria during simultaneous reduction of sulfate and uranium and to determine the phase in which uranium exists after it has been reduced and precipitated from solution. The studies were conducted in a laboratory-scale chemostat under substrate-limited growth conditions with pyruvate as the substrate. Kinetic coefficients for substrate utilization and cell growth were calculated using the Monod equation. The maximum rate of substrate utilization (k) was determined to be 4.70 days -1 while the half-velocity constant (K s ) was 140 mg/l COD. The yield coefficient (Y) was determined to be 0.17 mg cells/mg COD while the endogenous decay coefficient (k d ) was calculated as 0.072 days -1 . After reduction, U(IV) Precipitated from solution in the uraninite (UO 2 ) phase. Uranium removal efficiency as high as 90% was achieved in the chemostat

  3. Simultaneous determination of ten illegal azo dyes in feed by ultra-high performance liquid chromatography tandem mass spectrometry

    Directory of Open Access Journals (Sweden)

    Piątkowska Marta

    2017-09-01

    Full Text Available Introduction: The paper presents the method of simultaneous determination of 10 illegal azo dyes in feed by ultra-high performance liquid chromatography coupled with tandem mass spectrometry technique. Material and Methods: The dyes were extracted with hexane, evaporated to dryness, and analysed. Separation was achieved in 7 min in a gradient elution using acetonitrile (A and 0.1% formic acid (B as a mobile phase. Results: The validation results showed the repeatability of the method, which was evaluated at three levels (50, 500, and 5,000 μg/kg. All the matrix calibration curves for the working ranges were linear (R2 0.9904 to 1.0, the repeatability was between 2.1% and 24%, and recoveries ranged from 77.9% to 120%. The LOD and LOQ were at 1-2 and 5-10 μg/kg for different dyes, respectively. Furthermore, the method was applied in the homogeneity tests of the in-house prepared feed containing Sudan I at the levels of 0.5, 5, and 50 mg/kg. Conclusions: A sensitive, selective, and fast multiresidue method was successfully developed and validated. Its robustness was confirmed by the analysis of an experimental feed containing Sudan I.

  4. Application of single immunoaffinity clean-up for simultaneous determination of regulated mycotoxins in cereals and nuts.

    Science.gov (United States)

    Vaclavikova, Marta; MacMahon, Shaun; Zhang, Kai; Begley, Timothy H

    2013-12-15

    A rapid and sensitive analytical strategy for the simultaneous determination of twelve mycotoxins (aflatoxins, fumonisins, zearalenon, deoxynivalenol, ochratoxin A, T-2 and HT-2 toxins) using ultra-high performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS) was developed and validated. The method was validated for peanuts, barley and maize-breakfast cereals; selected as they represent the matrices most often contaminated by mycotoxins. The method is designed for fast and reliable analyses of mycotoxins in regulatory, industrial and private laboratories. Multi-target immunoaffinity columns containing antibodies for all mycotoxins studied herein were used for sample clean-up. Method optimization was predominantly focused on the simplification of extraction and clean-up procedure recommended by column producers. This newly developed and simplified procedure decreased both the sample preparation time and the solvent volumes used for their processing. The analysis of all regulated mycotoxins was conducted by a newly developed UHPLC-MS/MS method with a sample run time of only ten minutes. The method trueness was tested with analytical spikes and certified reference materials, with recoveries ranging from 71% to 112% for all of the examined mycotoxins. Published by Elsevier B.V.

  5. Simultaneous determination of alkyl mesilates and alkyl besilates in finished drug products by direct injection GC/MS.

    Science.gov (United States)

    Wollein, Uwe; Schramek, Nicholas

    2012-01-23

    We report a specific, fast and feasible method for the simultaneous determination of methyl mesilate (MMS), ethyl mesilate (EMS), isopropyl mesilate (IMS), methyl besilate (MBS) and ethyl besilate (EBS) in finished drug products by GC/MS. Sample preparation was carried out by liquid extraction. The analytes were directly injected into the chromatographic system and quantified with the internal standard method using methyl tosylate (MTS) as internal standard (ISTD). The method gives excellent sensitivity for all the alkyl and aryl esters at typical target analyte level, according to the acceptance criteria that are described in the Guideline on the Limits of Genotoxic Impurities which has been issued in 2007 by the European Medicines Agency (EMA). The average recovery for methanesulfonic acid esters (mesilates) was not lower than 71%, for benzenesulfonic acid esters (besilates) not lower than 94%. A linear range with R² ≥ 0.9998 has been established for concentrations between 0.01 and 1.33 μg/ml. Validation of the method was carried out on a sample matrix containing MMS, EMS, IMS, MBS and EBS at relevant levels and was further confirmed on finished products containing APIs as mesilate salts (Bromocriptine mesilate, Doxazosin mesilate). Copyright © 2011 Elsevier B.V. All rights reserved.

  6. Simultaneous determination of buprenorphine, norbuprenorphine and naloxone in human plasma by liquid chromatography/tandem mass spectrometry.

    Science.gov (United States)

    Liu, Yongzhen; Li, Xiaohua; Xu, Allan; Nasser, Azmi F; Heidbreder, Christian

    2016-02-20

    A simple, sensitive and rapid liquid chromatography/electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) method was developed and validated for simultaneous quantification of naloxone, buprenorphine and its metabolite norbuprenorphine in human plasma. Human plasma samples were extracted using a single step liquid-liquid extraction, and then separated on an Imtakt Unison UK-C18 column (2.1×50mm, 3μm) using alkaline mobile phases with gradient elution. All of the analytes were detected in positive ion mode using multiple reaction monitoring (MRM). The method was validated and the specificity, linearity, lower limit of quantitation, precision, accuracy, recoveries and stability were determined. The linear range was 20-10000pg/mL for buprenorphine and norbuprenorphine; and 1-500pg/mL for naloxone. The correlation coefficient (R(2)) values for all three analytes were ≥0.995. The precision and accuracy for intra-day and inter-day were 63% and matrix effects were tracked by the deuterated internal standards (IS) with the IS-normalized matrix factor ranging from 0.96 to 1.33 for all three analytes. The validated method was successfully applied in a clinical pharmacokinetic study with low dose administration of sublingual buprenorphine and naloxone. Copyright © 2015 Elsevier B.V. All rights reserved.

  7. Simultaneous determination of mono- and disubstituted polyfluoroalkyl phosphates in drinking water by liquid chromatography-electrospray tandem mass spectrometry.

    Science.gov (United States)

    Ding, Huanhuan; Peng, Hui; Yang, Min; Hu, Jianying

    2012-03-02

    A sensitive liquid chromatography-electrospray tandem mass spectrometry method was established for the simultaneous determination of five monosubstituted polyfluoroalkyl phosphates (monoPAPs) and eight disubstituted polyfluoroalkyl phosphates (diPAPs) in drinking water. Complete separation and good retention for 13 polyfluoroalkyls phosphates (PAPs) were achieved with a Waters ACUITY UPLC BEH C8 column using a mixture of methanol/water containing 0.1% NH₄OH as the mobile phases. Extraction of drinking water samples was performed on weak anion exchange (WAX) cartridges, and the recoveries of target compounds were from 65 to 110%. The limits of quantization (LOQs) for 13 analytes were in the range of 0.4-40 ng/L. This method was applied to analyze the PAPs in drinking water samples from three cities in China. Of the 13 PAPs, six PAPs including 6:2 monoPAP (13.0 ng/L), 8:2 monoPAP (3.6 ng/L), 10:1 monoPAP (4.3-70.3 ng/L), 10:2 monoPAP (1.4-5.6 ng/L), 8:2 diPAP (0.10 ng/L), and 10:1 diPAP (0.8-3.8 ng/L) were detected. Copyright © 2012 Elsevier B.V. All rights reserved.

  8. Simultaneous determination of chlorpheniramine maleate, phenylephrine hydrochloride, paracetamol and caffeine in pharmaceutical preparation by RP-HPLC

    Directory of Open Access Journals (Sweden)

    Redasani V.K.

    2013-01-01

    Full Text Available Reversed-phase High-Performance Liquid-Chromatography (RP-HPLC method was successfully developed for the simultaneous determination of quaternary mixture consisting of chlorpheniramine maleate (CPM, phenylephrine hydrochloride (PE, paracetamol (PCM and caffeine in pharmaceutical preparation. The method was found to be simple, sensitive and rapid. The separation of the drugs was carried out using Inertsil ODS C18 column using 0.05M dibasic phosphate buffer: acetonitrile (93: 07; v/v as mobile phase. The flow rate of mobile phase was adjusted to 1.5 ml/min and column oven temperature was kept at 30ᴼC. All these drugs were resolved successfully with retention times 2.74 (CPM, 3.48(PE, 9.5(PCM and 26.32(Caffeine minutes when detection was carried out at 215 nm. Correlation coefficient was found 0.999, 0.998, 0.999 and 0.999 respectively for CPM, PE, PCM and Caffeine. The relative standard deviation in the tablets was found less than 2% for six replicates. The method was validated for precision and accuracy. Thus, proposed method can be successfully applicable to the pharmaceutical preparation containing the above mentioned drugs without any interference of excipients.

  9. Development and validation of UPLC-MS/MS method for simultaneous determination of gestodene and ethinyl estradiol in rat plasma.

    Science.gov (United States)

    Xiong, Zhili; Sun, Xiaohong; Huo, Taoguang; Li, Ning; Zheng, Yan; Sun, Yi

    2010-02-01

    A selective and sensitive ultra-performance liquid chromatography method with tandem mass spectrometric detection for simultaneous determination of gestodene (GES) and ethinyl estradiol (EE) in rat plasma was developed and validated. GES, EE and the internal standard, norgestrel, were extracted with ethyl acetate, derivatized (EE only) with dansyl chloride and then back-extracted into diethyl ether-hexane (2:1, v/v). The separation was performed on an ACQUITY UPLC BEH C(18) column with gradient elution using mobile phase consisting of acetonitrile and water (both containing 0.1% formic acid). The detection was carried out by means of electrospray ionization (ESI) mass spectrometry in positive ion mode with multiple-reaction monitoring. Calibration curves of GES and EE were linear (r(2) >or= 0.99) over the concentration ranges 1.59-159 and 0.196-78.4 ng/mL, respectively. The intra- and inter-day precisions were not more than 6.9 and 12.9% for GES and 10.6 and 9.0% for EE, and the accuracies were -2.5-8.0% for GES, and -7.2-0.19% for EE, respectively. The method herein described was superior to previous methods and was applicable to the pharmacokinetic study of GES and EE in rats. (c) 2009 John Wiley & Sons, Ltd.

  10. Simultaneous Determination of the Main Peanut Allergens in Foods Using Disposable Amperometric Magnetic Beads-Based Immunosensing Platforms

    Directory of Open Access Journals (Sweden)

    Víctor Ruiz-Valdepeñas Montiel

    2016-06-01

    Full Text Available In this work, a novel magnetic beads (MBs-based immunosensing approach for the rapid and simultaneous determination of the main peanut allergenic proteins (Ara h 1 and Ara h 2 is reported. It involves the use of sandwich-type immunoassays using selective capture and detector antibodies and carboxylic acid-modified magnetic beads (HOOC-MBs. Amperometric detection at −0.20 V was performed using dual screen-printed carbon electrodes (SPdCEs and the H2O2/hydroquinone (HQ system. This methodology exhibits high sensitivity and selectivity for the target proteins providing detection limits of 18.0 and 0.07 ng/mL for Ara h 1 and Ara h 2, respectively, with an assay time of only 2 h. The usefulness of the approach was evaluated by detecting the endogenous content of both allergenic proteins in different food extracts as well as trace amounts of peanut allergen (0.0001% or 1.0 mg/kg in wheat flour spiked samples. The developed platform provides better Low detection limits (LODs in shorter assay times than those claimed for the allergen specific commercial ELISA kits using the same immunoreagents and quantitative information on individual food allergen levels. Moreover, the flexibility of the methodology makes it readily translate to the detection of other food-allergens.

  11. Determine Multiple Elements Simultaneously in the Sera of Umbilical Cord Blood Samples-a Very Simple Method.

    Science.gov (United States)

    Liang, Chunmei; Li, Zhijuan; Xia, Xun; Wang, Qunan; Tao, Ruiwen; Tao, Yiran; Xiang, Haiyun; Tong, Shilu; Tao, Fangbiao

    2017-05-01

    Analyzing the concentrations of heavy metals in the sera of umbilical cord blood samples can provide useful information about prenatal exposure to environmental agents. An analytical method based on ICP-MS to simultaneously determine multiple elements in umbilical cord blood samples was developed for assessing the in utero exposure to metallic and metalloid elements. The method only required as little as 100 μL of serum diluted 1:25 for direct analysis. Matrix-matched protocol was used to eliminate mass matrix interference and kinetic energy discrimination mode was used to eliminate the polyatomic ion interference. The assay was completed on average within 4 min with the detection limits ranging from 0.0002 to 44.4 μg/L for all the targeted elements. The detection rates for most of elements were 100 % other than cadmium (Cd), lead (Pb), and mercury (Hg). The testing results of the certified reference materials were ideal. The method is simple and sensitive, so it is suitable for the monitoring of large quantities of samples.

  12. Electrochemical sensor based on graphene and mesoporous TiO2 for the simultaneous determination of trace colourants in food.

    Science.gov (United States)

    Gan, Tian; Sun, Junyong; Meng, Wen; Song, Li; Zhang, Yuxia

    2013-12-15

    Currently, synthetic colourants draw much attention as food additives. This paper investigated the simultaneous electrocatalytic oxidation of sunset yellow and tartrazine, two yellow colourants commonly present in food together, with a novel voltammetric sensor based on graphene and mesoporous TiO2 modified carbon paste electrode. Due to the high accumulation effect and great catalytic capability of graphene and mesoporous TiO2, the developed sensor exhibited well-defined and separate square wave voltammetric peaks (i.e., 272 mV) for sunset yellow tartrazine. The peak currents of sunset yellow and tartrazine increased linearly with their concentration in the ranges of 0.02-2.05 μM and 0.02-1.18 μM, respectively. And the detection limit was 6.0 and 8.0 nM for sunset yellow and tartrazine, respectively. This new sensor was applied to determine sunset yellow and tartrazine in several food sample extracts. Results suggested that the proposed sensor was sensitive, rapid and reliable. Copyright © 2013 Elsevier Ltd. All rights reserved.

  13. Self-assembly of graphitic carbon nitride nanosheets–carbon nanotube composite for electrochemical simultaneous determination of catechol and hydroquinone

    International Nuclear Information System (INIS)

    Zhang, Hanqiang; Huang, Yihong; Hu, Shirong; Huang, Qitong; Wei, Chan; Zhang, Wuxiang; Yang, Weize; Dong, Peihui; Hao, Aiyou

    2015-01-01

    Graphical abstract: Schematic diagram of hydrothermal synthesis graphitic carbon nitride nanosheets-carbon nanotube composite and theirs application for electrochemical sensing catechol and hydroquinone. - Highlights: • Self-assembly of graphitic carbon nitride nanosheets-carbon nanotube composite. • CNNS-CNT show more stronger conductivity than CNNS and CNT. • CNNS-CNT has been performed for detection of catechol and hydroquinone. • The probe was applied to detect practical samples with satisfactory results. - Abstract: In this paper, three-dimensional (3D) graphitic carbon nitride nanosheets-carbon nanotube (CNNS-CNT) composite was synthesized via hydrothermal reaction of 2D CNNS and 1D CNT-COOH by π-π stacking and electrostatic interactions. This CNNS-CNT composite was characterized by transmission electron microscope, scanning electron microscope, x-ray diffraction and fourier-transform infrared. In addition, the CNNS-CNT composite displayed excellent conductivity comparing with CNNS and CNT-COOH monomer. This composite was applied for electrochemical simultaneous determination of catechol (CC) and hydroquinone (HQ) with good sensitivity, wide linear range and low detection limit. In addition, this CNNS-CNT composite modified electrode was also applied to detect practical samples with satisfactory results

  14. Simultaneous Determination of Caffeine and Vitamin B6 in Energy Drinks by High-Performance Liquid Chromatography (HPLC)

    Science.gov (United States)

    Leacock, Rachel E.; Stankus, John J.; Davis, Julian M.

    2011-01-01

    A high-performance liquid chromatography experiment to determine the concentration of caffeine and vitamin B6 in sports energy drinks has been developed. This laboratory activity, which is appropriate for an upper-level instrumental analysis course, illustrates the standard addition method and simultaneous determination of two species. (Contains 1…

  15. Simultaneous extraction and determination of HBCD isomers and TBBPA by ASE and LC-MSMS in fish

    NARCIS (Netherlands)

    Dam, ten G.; Pardo, O.; Traag, W.A.; Lee, van der M.K.; Peters, R.J.B.

    2012-01-01

    Since the EFSA enquired a call for data for TBBPA and HBCD in 2009, the analytical determination of these compounds in food became of regulatory interest. Therefore, a method for the simultaneous determination of TBBPA and the three major HBCD stereoisomers was developed. Conventional techniques

  16. An HPLC-DAD method for the simultaneous determination of nine β-lactam antibiotics in ewe milk.

    Science.gov (United States)

    Cámara, M; Gallego-Picó, A; Garcinuño, R M; Fernández-Hernando, P; Durand-Alegría, J S; Sánchez, P J

    2013-11-15

    The presence of β-lactam residues in foodstuffs constitutes a potential risk to the human health and undesirable effects on consumers, and nowadays these antibiotic residues are also recognised as an emerging environmental problem. In addition, these are of great concern to prestigious Manchego cheese processors (Central Spain denomination of origin) because they reduce the curdling of milk and cause improper cheese ripening, which consequently lead to an important loss of monetary income. This work describes the development of a sensitive and reliable method using liquid chromatography with UV-diode array detection (LC-DAD) for simultaneous determination of the β-lactam antibiotics, ampicillin (AMP), benzylpenicillin (PEG), cephalexin (CFX), cefazolin (CFL), cefoperazone (CFP), cloxacillin (CLO), dicloxacillin (DCL), oxacillin (OXA) and phenoxymethylpenicillin (PEV), in Manchega ewe milk. The column, mobile phase, temperature and flow rate were optimised to provide the best resolution of these analytes. The extraction method of the antibiotic residues involves the deproteinisation of the milk sample using acetonitrile and centrifugation followed by a solid-phase extraction (SPE) clean-up. The recoveries for the studied β-lactams ranged from 79% to 96% with relative standard deviations between 0.5% and 4.9%. The limits of quantification (LOQs) for all these compounds were in the range of 3.4-8.6μgkg(-1), which are lower than the maximum residue limits (MRLs) established by the European Union for the studied β-lactams in milk, making the method suitable for performing routine analyses. The proposed multi-residue LC-UV-diode array detection (LC-DAD) method is a powerful and popular alternative for the determination and confirmation of antibiotic residues in small milk industries and is the first one capable of determining nine β-lactam antibiotics in samples of Manchega ewe milk. Copyright © 2013 Elsevier Ltd. All rights reserved.

  17. Simultaneous determination of chloramphenicol, florfenicol and florfenicol amine in ham sausage with a hybrid chemiluminescent immunoassay.

    Science.gov (United States)

    Tao, Xiaoqi; Jiang, Haiyang; Yu, Xuezhi; Zhu, Jinghui; Wang, Xia; Wang, Zhanhui; Niu, Lanlan; Wu, Xiaoping; Shen, Jianzhong

    2013-01-01

    A novel chemiluminescent immunoassay utilising two types of primary antibodies (murine monoclonal antibody and rabbit polyclonal antibody) and two types of horseradish peroxidase-labelled secondary antibodies was established for simultaneously detecting multiple amphenicol residues in ham sausage. After combining the extract procedure of the target amphenicol into one simplified method, this hybrid chemiluminescent immunoassay could screen chloramphenicol (CAP), florfenicol (FF) and its metabolite florfenicol amine (FFA) at the same time by adding the corresponding secondary antibody. Ham sausage samples were analysed by using this hybrid immunoassay, with LODs of CAP being 0.01 μg kg⁻¹, of FF being 2.8 μg kg⁻¹ and of FFA being 3.0 μg kg⁻¹. The applicability of the proposed method has been validated by determining CAP, FF and FFA in ham sausage samples with satisfactory results. Good recoveries and high correlation with traditional enzyme-linked immunosorbent assay and LC-MS/MS results illustrated that the developed hybrid chemiluminescent immunoassay could screen high-throughput ultra-trace amphenicol residues effectively at one time.

  18. Simultaneous determination of organic acids and vitamin C in green beans by liquid chromatography.

    Science.gov (United States)

    Vazquez Oderiz, M L; Vazquez Blanco, M E; Lopez Hernandez, J; Simal Lozano, J; Romero Rodriguez, M A

    1994-01-01

    A method is described for determining and quantitating organic acids (oxalic, malic, citric, and fumaric) and vitamin C by liquid chromatography with a UV-visible detector that allows simultaneous monitoring at 2 wavelengths. The method was applied to samples of green beans (Phaseolus vulgaris L.). Recoveries were 97.8% for oxalic acid, 98.9% for malic acid, 98.7% for citric acid, 99.2% for fumaric acid, and 98.5% for vitamin C. Method precisions (coefficients of variation) were 1.7% for oxalic acid, 0.8% for malic acid, 0.9% for citric acid, 1.5% for fumaric acid, and 1.2% for vitamin C. Measurement precisions (coefficients of variation) were 1.32% for oxalic acid, 0.33% for malic acid, 0.62% for citric acid, 1.01% for fumaric acid, and 0.39% for vitamin C. Limits of detection were 0.025 mg/mL for oxalic acid, 0.022 mg/mL for malic acid, 0.024 mg/mL for citric acid, 1.0 x 10(-4) mg/mL for fumaric acid, and 2.7 x 10(-4) mg/mL for vitamin C.

  19. Simultaneous determination of urea and melamine in milk powder by nonlinear chemical fingerprint technique.

    Science.gov (United States)

    Ma, Yongjie; Dong, Wenbin; Bao, Hongliang; Fang, Yue; Fan, Cheng

    2017-04-15

    This paper proposed a nonlinear chemical fingerprint method for simultaneous determination of urea and melamine in milk powder using "H + +Ce 4+ +BrO 3 - +malonic acid" as reaction system. A multiple linear relationship was obtained between the adulterants content in milk powder and inductive time of corresponding mixed milk powder. System analysis model established with classical least squares (CLS) method was then used to calculate the content of urea and melamine in milk powder. The method was successfully applied to milk powder samples and had good recoveries in the range of 99.17-100.25%, with the relative standard deviation (RSD) in the range of 0.60-4.12%. The limits of detection for urea and melamine were 0.33μg·g -1 and 0.05μg·g -1 , respectively. The limits of quantification were 1.11μg·g -1 and 0.18μg·g -1 , respectively. The results indicated that the new method was feasible and had the advantages of low cost, simple operation and without pretreatment of samples. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Simultaneous determination of ethinyl estradiol and drospirenone in oral contraceptive by high performance liquid chromatography

    Directory of Open Access Journals (Sweden)

    Viviane Benevenuti Silva

    2013-09-01

    Full Text Available A simple, rapid, economical and reliable high performance liquid chromatographic method has been developed and successfully applied in simultaneous determination of ethinyl estradiol and drospirenone in coated tablets. The HPLC method was performed on a LiChroCART® 100RP column (125x4 mm i.d., 5 µm with acetonitrile:water 50:50 (v/v as mobile phase, pumped at a flow rate of 1.0 mL.min-1. The fluorescence detection for ethinyl estradiol was made at λex= 280 nm and λem= 310 nm and a UV detection for drospirenone was made at 200 nm. The elution time for ethinyl estradiol and drospirenone were 4.0 and 5.7 min, respectively. The method was validated in accordance to USP 34 guidelines. The proposed HPLC method presented advantages over reported methods and is suitable for quality control assays of ethinyl estradiol and drospirenone in coated tablets.

  1. Simultaneous determination of 11 preservatives in cosmetics by high-performance liquid chromatography.

    Science.gov (United States)

    Aoyama, Airin; Doi, Takahiro; Tagami, Takaomi; Kajimura, Keiji

    2014-10-01

    Preservatives prevent the growth of microorganisms in foods, pharmaceuticals and cosmetics. There exist numerous restrictions regarding the maximum allowable levels of preservatives in cosmetics. We analyzed 11 regulated preservatives in commercial cosmetics and manufacturers need to analyze their products for quality control purposes. However, methods used in previous studies to date have been inadequate for use by public institutions and manufacturers. Therefore, an effective, scalable method for the analysis of preservatives in cosmetics is required. We developed a novel method for the simultaneous determination of 11 regulated preservatives in cosmetics by high-performance liquid chromatography (HPLC). We applied the samples to a C18 column in a simple mobile phase (5 mmol/L ammonium formate solution and acetonitrile) with gradient elution at a flow rate of 1.0 mL/min at a single wavelength (230 nm). The correlation coefficients of the calibration curves were >0.997. The percent recoveries were 92.8-111.9% and the relative standard deviations were 1.9. Because of the simple conditions for isolation and complete separation, the HPLC method can be effectively applied to the analysis of preservatives in commercially retailed cosmetics. © The Author [2013]. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  2. Stability indicating RP-HPLC method for simultaneous determination of piroxicam and ofloxacin in binary combination.

    Science.gov (United States)

    John, Peter; Azeem, Waqar; Ashfaq, Muhammad; Khan, Islam Ullah; Razzaq, Syed Naeem

    2015-09-01

    A simple and precise RP-HPLC method was developed for simultaneous determination of piroxicam and ofloxacin in pharmaceutical formulations and human serum. Optimum separations of piroxicam, ofloxacin and stress-induced degradation products were achieved by use of Hypersil BDS C8 column (250 x 4.6mm, 5 μm). The mobile phase was a mixture of acetonitrile: 0.012M K2HPO4: 0.008M sodium citrate (both buffers mixed and pH adjusted to 2.8) (50:25:25 v/v/v) delivered at flow rate of 1.5 mL min⁻¹ using DAD at 254 nm. Response was linear function of concentration over the ranges of 70-130 mg mL⁻¹ for piroxicam and ofloxacin (r² ≥ 0.999). The method efficiently separated the analytical peaks from degradation products with acceptable tailing and resolution. The developed method was successfully used for concurrent analysis of piroxicam and ofloxacin in pharmaceutical formulations, human serum and in vitro drug interaction studies.

  3. Simultaneous Determination of Different Anions in Milk Samples Using Ion Chromatography with Conductivity Detection

    Directory of Open Access Journals (Sweden)

    Gülçin Gümüş Yılmaz

    2016-12-01

    Full Text Available The description of a simple method for simultaneous determination of chloride, nitrate, sulfate, iodide, phosphate, thiocyanate, perchlorate, and orotic acid in milk samples was outlined. The method involves the use of dialysis cassettes for matrix elimination, followed by ion chromatography on a high capacity anion exchange column with suppressed conductivity detection. The novelty of dialysis process was that it did not need any chemical and organic solvent for elimination of macromolecules such as fat, carbohydrates and proteins from milk samples. External standard calibration curves for these analytes were linear with great correlation coefficients. The relative standard deviations of analyte concentrations were acceptable both inter-day and intra-day evaluations. Under optimized conditions, the limit of detection (Signal-to-Noise ratio = 3 for chloride, phosphate, thiocyanate, perchlorate, iodide, nitrate, sulfate, and orotate was found to be 0.012, 0.112, 0.140, 0.280, 0.312, 0.516, 0.520, and 0.840 mg L−1, respectively. Significant results were obtained for various spiked milk samples with % recovery in the range of 93.88 - 109.75 %. The proposed method was successfully applied to milk samples collected from Istanbul markets. The advantages of the method described herein are reagent-free, simple, and reliable.

  4. Simultaneous determination of 38 veterinary antibiotic residues in raw milk by UPLC-MS/MS.

    Science.gov (United States)

    Han, R W; Zheng, N; Yu, Z N; Wang, J; Xu, X M; Qu, X Y; Li, S L; Zhang, Y D; Wang, J Q

    2015-08-15

    A selective and rapid method has been developed to determine, simultaneously, 38 veterinary antibiotic residues in raw milk by ultra-high-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). One milliliter of raw milk was diluted with 0.5 mL water and 3 mL acetonitrile, then purified using an Oasis HLB cartridge. The eluates were evaporated by nitrogen drying and then reconstituted to 4 mL with water/acetonitrile (8:1) before being injected into the UPLC-MS/MS system. The results indicated recoveries of 68-118% for 14 β-lactams, 79-118% for eight quinolones, 71-106% for eight sulfonamides, 76-116% for four tetracyclines, 78-106% for three macrolides, and 88-103% for one lincosamides, with coefficients of variation less than 15% for intraday and interday precisions. The limit of quantification for all antibiotics was 0.03-10 μg kg(-1). This methodology was then applied to field-collected real raw milk samples and trace levels of four antibiotics were detected. Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. Simultaneous determination of flavonoids in chrysanthemum by capillary zone electrophoresis with running buffer modifiers.

    Science.gov (United States)

    Zhang, Shan; Dong, Shuqing; Chi, Langzhu; He, Pingang; Wang, Qingjiang; Fang, Yuzhi

    2008-08-15

    Despite the separation efficiency of capillary electrophoresis (CE) is much higher than other chromatographic methods, it is sometimes difficult to perfectly separate the complex ingredients in biological samples. One possible and simple way to develop the separation effect in CE is to add some modifiers in the running buffer. In this paper, the suitable running buffer modifiers were explored to simultaneously separate and detect six typical flavonoids (apigenin, luteolin, kaempferol, quercetin, (+)-catechin and (-)-epicatechin) which are the main active ingredients in chrysanthemum by capillary zone electrophoresis with amperometric detection (CZE-AD). It was found that when beta-cyclodextrin (beta-CD) and the mixture of methanol and ethanol were used as running buffer modifiers, a baseline separation of the six analytes could be accomplished in less than 20 min and the detection limits were as low as 10(-7) or 10(-8)gm l(-1). Other factors affecting the CZE separation, such as working potential, pH value and ionic strength of running buffer, separation voltage and sample injection time were extensively investigated. Under the optimum conditions, a successful practical application on the determination of chrysanthemum samples confirmed the validity and practicability of this method.

  6. Simultaneous Determination of Cromolyn Sodium Combined Dosage Forms Using Isocratic HPLC Method.

    Science.gov (United States)

    Fathy, M E; Abo El Abass Mohamed, S; Elmansi, H; Belal, F

    2017-01-01

    A simple and selective reversed-phase high-performance liquid chromatography method was developed for the estimation of cromolyn sodium (CRM) with either oxymetazoline hydrochloride (OMZ) or xylometazoline hydrochloride (XMZ) in their binary mixtures. The method is based on the simultaneous separation of each drug in a reversed-phase Waters symmetry ® C18 column (250 mm × 4.6 mm intradermally, 5-µm particle size) at 25°C. Elution was performed with a mobile phase consisting of methanol : 0.1 M phosphate buffer (60:40, v/v, pH 4.0). Quantitation was achieved with ultraviolet detection at 220 nm. The method could determine the three drugs, with linearity, in the range of 2.0-100.0 µg/mL for CRM and 0.8-8.0 µg/mL for OMZ and for XMZ. Aspirin was used as internal standard. Optimization of the separation in terms of mobile phase composition is critical to the method development, which is discussed in detail. The suggested procedure was successfully applied to the analysis of the studied drugs in their nasal preparations. Statistical evaluation of the data obtained by the proposed and comparison methods revealed good accuracy of the proposed method. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  7. Simultaneous Determination of Fluoroquinolones and Sulfonamides Originating from Sewage Sludge Compost

    Directory of Open Access Journals (Sweden)

    K. Kipper

    2017-01-01

    Full Text Available A simultaneous method for quantitative determination of traces of fluoroquinolones (FQs and sulfonamides (SAs in edible plants fertilized with sewage sludge was developed. The compounds were extracted from the plants by rapid and simple liquid extraction followed by extracts clean-up using solid phase extraction. The eluent additive 1,1,1,3,3,3-hexafluoro-2-propanol was used for liquid chromatographic detection to achieve separation of structurally similar antimicrobials like ciprofloxacin and norfloxacin. Identification and quantification of the compounds were performed using high-performance liquid chromatography with electrospray ionization mass spectrometry in selected reaction monitoring mode. Method was validated and extraction recoveries of FQs and SAs ranged from 66% to 93%. The limit of quantifications was from 5 ng/g in the case of ofloxacin to 40 ng/g for norfloxacin. The method precision ranged from 1.43% to 2.61%. The developed novel method was used to evaluate the plats antimicrobial uptake (potato (Solanum tuberosum L., carrot (Daucus carota L., lettuce (Lactuca sativa L., and wheat (Triticum vulgare L. from soil and migration of the analytes inside the plants.

  8. HPTLC Method for Simultaneous Determination of Lopinavir and Ritonavir in Capsule Dosage Form

    Directory of Open Access Journals (Sweden)

    A. V. Sulebhavikar

    2008-01-01

    Full Text Available A rapid and simple high performance thin layer chromatography (HPTLC method with densitometry at λ=263 nm was developed and validated for simultaneous determination of lopinavir and ritonavir from pharmaceutical preparation. Separation was performed on aluminum-backed silica gel 60F254 HPTLC plates as stationary phase and using a mobile phase comprising of toluene, ethyl acetate, methanol and glacial acetic acid, in the volume ratio of 7.0:2.0:0.5:0.5 (v/v respectively. After development, plates were observed under UV light. The detector response was linear in the range of 6.67 to 20.00 µg/spot and 1.67 to 5.00 µg/spot for lopinavir and ritonavir respectively. The validated lowest limit of detection was 21.00 ng/spot and 5.10 ng/spot whereas lowest limit of quantification was 7.00 ng/spot and 21.00 ng/spot for lopinavir and ritonavir respectively. The percentage assay of lopinavir and ritonavir was found between 98.23 to 102.28% and 98.03 to 103.50% respectively. The described method has the advantage of being rapid and easy. Hence it can be applied for routine quality control analysis of lopinavir and ritonavir from pharmaceutical preparation and stability studies.

  9. HPLC and chemometric assisted spectrophotometric methods for simultaneous determination of diprophylline, phenobarbitone and papaverine hydrochloride.

    Science.gov (United States)

    El-Gindy, Alaa

    2005-09-01

    Three methods are developed for the simultaneous determination of diprophylline (DP), phenobarbitone (PH) and papaverine hydrochloride (PP). The chromatographic method depends on a high performance liquid chromatographic (HPLC) separation on a reversed-phase C18 column with a mobile phase consisting of 0.02 M potassium dihydrogen phosphate, pH 3.5--acetonitrile (55:45 v/v). Quantitation was achieved with UV detection at 210 nm based on peak area. The other two chemometric methods applied were principal component regression (PCR) and partial least squares (PLS-1). These approaches were successfully applied to quantify the three drugs in the mixture using the information included in the UV absorption spectra of appropriate solutions in the range 215-245 nm with the intervals Delta lambda = 0.2 nm. The calibration PCR and PLS-1 models were evaluated by internal validation (prediction of compounds in its own designed training set of calibration), by cross-validation (obtaining statistical parameters that show the efficiency for a calibration fit model) and by external validation over laboratory-prepared mixtures and pharmaceutical preparations. The PCR and PLS-1 methods require neither any separation step, nor any priori graphical treatment of the overlapping spectra of the three drugs in a mixture. The results of PCR and PLS-1 methods were compared with HPLC method obtained in pharmaceutical formulation and a good agreement was found.

  10. Simultaneous determination of tebuconazole, trifloxystrobin, and its metabolite trifloxystrobin acid residues in gherkin under field conditions.

    Science.gov (United States)

    Paramasivam, Mariappan; Selvi, Chellamuthu; Deepa, Manthirachalam; Jayaprakash, Samiyannan A; Chandrasekaran, Subramanian

    2015-03-01

    A rapid, simple, and selective analytical method for the simultaneous determination of tebuconazole, trifloxystrobin, and its metabolite trifloxystrobin acid residues in gherkin and soil was developed and validated by gas chromatography coupled with mass spectrometry. The samples were extracted with acetonitrile and cleaned up by dispersive solid-phase extraction with primary secondary amine sorbent. The limit of quantification of the method was 0.05 mg/kg for all three compounds. The method was validated using blank samples spiked at three levels and recoveries ranged from 83.5 to 103.8% with a relative standard deviation of 1.2 to 4.8%. The developed method was validated and applied for the analysis of a degradation study sample. The residues of trifloxystrobin and tebuconazole were found to dissipate following first-order kinetics with half-life ranging between 3.31-3.38 and 3.0-3.04 days, respectively, for two different dosages. Pesticide residues were below the European Union maximum residue level after seven days for trifloxystrobin (0.2 mg/kg) and ten days for tebuconazole (0.05 mg/kg), which suggested the use of this fungicide mixture to be safe to humans. These results can be utilized in formulating the spray schedule and safety evaluation on trifloxystrobin and tebuconazole in gherkin crop. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Simultaneous AMS determination of {sup 14}C content and total carbon mass in biological samples

    Energy Technology Data Exchange (ETDEWEB)

    Zoppi, U., E-mail: uzoppi@acciumbio.co [Accium BioSciences, 550 17th Avenue, Suite 550, Seattle, WA 98122 (United States); Arjomand, A. [Accium BioSciences, 550 17th Avenue, Suite 550, Seattle, WA 98122 (United States)

    2010-04-15

    Accelerator Mass Spectrometry (AMS) is now recognized as one of the most powerful techniques available for conducting ultrasensitive clinical studies. However, since for biological applications the relevant quantity is the total {sup 14}C activity (i.e. dpm/mL sample), AMS {sup 14}C measurements must be combined with total carbon concentrations measured on a separate instrument using a different sample aliquot. This procedure is inherently a source of large inaccuracies, especially in non-homogeneous samples such as urine and fecal blends. To overcome this limitation we developed a new measurement technique whereby a small amount of {sup 13}C-enriched carbon carrier is added to each sample. Accurate measurement of the {sup 13}C/{sup 12}C and {sup 14}C/{sup 13}C ratios of the mix can be used to simultaneously calculate total carbon mass and {sup 14}C concentration of the original sample. In this paper we present our first test runs including a detailed error analysis demonstrating that sample mass and {sup 14}C concentration of the original sample can be determined with a precision and accuracy of better than 3%, thus significantly reducing the final uncertainty due to sample in-homogeneities.

  12. Neighborhood properties are important determinants of temperature sensitive mutations.

    Directory of Open Access Journals (Sweden)

    Svetlana Lockwood

    Full Text Available Temperature-sensitive (TS mutants are powerful tools to study gene function in vivo. These mutants exhibit wild-type activity at permissive temperatures and reduced activity at restrictive temperatures. Although random mutagenesis can be used to generate TS mutants, the procedure is laborious and unfeasible in multicellular organisms. Further, the underlying molecular mechanisms of the TS phenotype are poorly understood. To elucidate TS mechanisms, we used a machine learning method-logistic regression-to investigate a large number of sequence and structure features. We developed and tested 133 features, describing properties of either the mutation site or the mutation site neighborhood. We defined three types of neighborhood using sequence distance, Euclidean distance, and topological distance. We discovered that neighborhood features outperformed mutation site features in predicting TS mutations. The most predictive features suggest that TS mutations tend to occur at buried and rigid residues, and are located at conserved protein domains. The environment of a buried residue often determines the overall structural stability of a protein, thus may lead to reversible activity change upon temperature switch. We developed TS prediction models based on logistic regression and the Lasso regularized procedure. Through a ten-fold cross-validation, we obtained the area under the curve of 0.91 for the model using both sequence and structure features. Testing on independent datasets suggested that the model predicted TS mutations with a 50% precision. In summary, our study elucidated the molecular basis of TS mutants and suggested the importance of neighborhood properties in determining TS mutations. We further developed models to predict TS mutations derived from single amino acid substitutions. In this way, TS mutants can be efficiently obtained through experimentally introducing the predicted mutations.

  13. Sensitive determination of nucleic acids using organic nanoparticle fluorescence probes

    Science.gov (United States)

    Zhou, Yunyou; Bian, Guirong; Wang, Leyu; Dong, Ling; Wang, Lun; Kan, Jian

    2005-06-01

    This paper describes the preparation of organic nanoparticles by reprecipitation method under sonication and vigorous stirring. Transmission electron microscopy (TEM) was used to characterize the size and size distribution of the luminescent nanoparticles. Their average diameter was about 25 nm with a size variation of ±18%. The fluorescence decay lifetime of the nanoparticles also was determined on a self-equipped fluorospectrometer with laser light source. The lifetime (˜0.09 μs) of nanoparticles is about three times long as that of the monomer. The nanoparticles were in abundant of hydrophilic groups, which increased their miscibility in aqueous solution. These organic nanoparticles have high photochemical stability, excellent resistance to chemical degradation and photodegradation, and a good fluorescence quantum yield (25%). The fluorescence can be efficiently quenched by nucleic acids. Based on the fluorescence quenching of nanoparticles, a fluorescence quenching method was developed for determination of microamounts of nucleic acids by using the nanoparticles as a new fluorescent probe. Under optimal conditions, maximum fluorescence quenching is produced, with maximum excitation and emission wavelengths of 345 and 402 nm, respectively. Under optimal conditions, the calibration graphs are linear over the range 0.4-19.0 μg ml -1 for calf thymus DNA (ct-DNA) and 0.3-19.0 μg ml -1 for fish sperm DNA (fs-DNA). The corresponding detection limits are 0.25 μg ml -1 for ct-DNA and 0.17 μg ml -1 for fs-DNA. The relative standard deviation of six replicate measurements is 1.3-2.1%. The method is simple, rapid and sensitive with wide linear range. The recovery and relative standard deviation are very satisfactory.

  14. Is skin penetration a determining factor in skin sensitization ...

    Science.gov (United States)

    Summary:Background. It is widely accepted that substances that cannot penetrate through the skin will not be sensitisers. Thresholds based on relevant physicochemical parameters such as a LogKow > 1 and a MW 1 is a true requirement for sensitisation.Methods. A large dataset of substances that had been evaluated for their skin sensitisation potential, together with measured LogKow values was compiled from the REACH database. The incidence of skin sensitisers relative to non-skin sensitisers below and above the LogKow = 1 threshold was evaluated. Results. 1482 substances with associated skin sensitisation outcomes and measured LogKow values were identified. 305 substances had a measured LogKow self-evident truth borne out from the widespread misconception that the ability to efficiently penetrate the stratum corneum is a key determinant of skin sensitisation potential and potency. Using the REACH data extracted to test out the validity of common assumptions in the skin sensitization AOP. Builds on trying to develop a proof of concept IATA

  15. Simultaneous determination of non-steroidal anti-inflammatory drugs in pharmaceutical formulations and human serum by reversed phase high performance liquid chromatography

    Directory of Open Access Journals (Sweden)

    Muhammad Nawaz

    2012-01-01

    Full Text Available A rapid and sensitive method using high performance liquid chromatography has been developed and validated for the simultaneous determination of non-steroidal anti-inflammatory drugs (NSAIDs in pharmaceutical formulations and human serum. Six NSAIDs including: naproxen sodium, diclofenac sodium, meloxicam, flurbiprofen, tiaprofenic and mefenamic acid were analyzed simultaneously in presence of ibuprofen as internal standard on Mediterranea C18 (5 µm, 250 x 0.46 mm column. Mobile phase comprised of methanol: acetonitrile: H2O (60:20:20, v/v; pH 3.35 and pumped at a flow rate of 1 mL min-1 using 265 nm UV detection. The method was linear over a concentration range of 0.25-50 µg mL-1 (r² = 0.9999.

  16. Simultaneous determination of nineteen major components in Qi She Pill by ultra-high-performance liquid chromatography?tandem mass spectrometry

    OpenAIRE

    Zhang, Zhongliang; Li, Qiang; Li, Qiufen; Du, Simiao; Zhou, Yongquan; Lv, Chunming; Zhao, Yan; Wang, Yongjun; Zhang, Ning

    2014-01-01

    Qi She Pill (QSP) is a traditional Chinese medicine (TCM) prescription that has been used in treating cervical spondylosis radiculopathy for many years. In this study, a simple and sensitive method using ultra-high-performance liquid chromatography–tandem mass spectrometry (UHPLC–MS/MS) on a reverse-phase C18 column was developed for the simultaneous determination of the 19 major components in QSP. We found that the optimum mobile phase for gradient elution was 0.1% formic acid and methanol. ...

  17. A sensitive and rapid mass spectrometric method for the simultaneous measurement of eight steroid hormones and CALIPER pediatric reference intervals.

    Science.gov (United States)

    Kyriakopoulou, L; Yazdanpanah, M; Colantonio, D A; Chan, M K; Daly, C H; Adeli, K

    2013-05-01

    To develop an accurate assay and establish the normal reference intervals for serum cortisol, corticosterone, 11-deoxycortisol, androstenedione, 21-hydroxyprogesterone, testosterone, 17-hydroxyprogesterone, and progesterone. These steroids are commonly used as biomarkers for the diagnosis and monitoring of endocrine diseases such as congenital adrenal hyperplasia. Appropriate age- and gender-stratified reference intervals are essential in accurate interpretation of steroid hormone levels. The samples analyzed in this study were collected from healthy, ethnically diverse children in the Greater Toronto Area as part of the CALIPER program. A total of 337 serum samples from children between the ages of 0 and 18years were analyzed. The concentrations were measured by using an LC-MS/MS method. The data were analyzed for outliers and age- and gender-specific partitions were established prior to establishing the 2.5th and 97.5th percentiles for the reference intervals. Reference intervals for all hormones required significant age-dependent stratification while testosterone and progesterone required additional sex-dependent stratification. We report a sensitive, accurate and relatively fast LC-MS/MS method for the simultaneous measurement of eight steroid hormones. Detailed reference intervals partitioned based on both age and gender were also established for all eight steroid hormones. Copyright © 2013 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.

  18. Dot immunoassay for the simultaneous determination of postvaccination immunity against pertussis, diphtheria, and tetanus.

    Science.gov (United States)

    Khramtsov, Pavel; Bochkova, Maria; Timganova, Valeria; Zamorina, Svetlana; Rayev, Mikhail

    2017-06-01

    A dot immunoassay for simultaneous semiquantitative detection of IgG against tetanus toxoid (Ttx) and diphtheria toxoid (Dtx) and qualitative detection of anti-Bordetella pertussis IgGs in human blood serum using carbon nanoparticles functionalized with streptococcal protein G was developed. Inactivated B. pertussis cells in suspension form were used as an antigen in the immunoassay. Pertussis, tetanus, and diphtheria antigens were separately spotted onto nitrocellulose strips, and then the immunostrips were successively incubated with blood sera and a suspension of carbon nanoparticles. The immunostrips were then scanned with a flatbed scanner, and the images obtained were processed with ImageJ. One hundred fifty-five venous blood serum samples from children vaccinated with diphtheria, tetanus, and whole-cell pertussis (DTwP) vaccine were tested in comparison with a conventional ELISA and agglutination test. The total time required for analysis of 32 serum samples was less than 3 h. Comparison between the results of the dot immunoassay and the corresponding ELISA/agglutination test revealed a high level of agreement (Cohen's kappa between 0.765 and 0.813). The lower limit of quantification was 0.06 IU/ml for anti-Ttx and anti-Dtx. The intra-assay coefficients of variation were less than 15% for anti-Ttx and anti-Dtx and less than 10% for anti-pertussis. The diagnostic sensitivity of detection of the antibody protection level was 93.5% for anti-Ttx [95% confidence interval (CI) 83.5-97.9%], 92.4% for anti-Dtx (95% CI 80.9297.5%), and 90.2% for anti-pertussis (95% CI 75.9-96.8%). The diagnostic specificity was 90.9% for anti-Ttx (95% CI 57.1-99.5%), 85% for anti-Dtx (95% CI 61.1-96.0%), and 89.3% for anti-pertussis (95%CI 80.8-94.5%). The dot immunoassay developed does not require expensive reading equipment, and allows detection of antibodies against three antigens in a single analysis. The immunostrips can be stored for a long time without changes in the

  19. Sensitive and simultaneous analysis of five transgenic maizes using multiplex polymerase chain reaction, capillary gel electrophoresis, and laser-induced fluorescence.

    Science.gov (United States)

    García-Cañas, Virginia; González, Ramón; Cifuentes, Alejandro

    2004-07-01

    The benefits of using multiplex polymerase chain reaction (PCR) followed by capillary gel electrophoresis with laser-induced fluorescence (CGE-LIF) for the simultaneous detection of five transgenic maizes (Bt11, T25, MON810, GA21, and Bt176) are demonstrated. The method uses a hexaplex PCR protocol to amplify the five mentioned transgenic amplicons plus the zein gene used as reference, followed by a CGE-LIF method to analyze the six DNA fragments. CGE-LIF was demonstrated very useful and informative for optimizing multiplex PCR parameters such as time extension, PCR buffer concentration and primers concentration. The method developed is highly sensitive and allows the simultaneous detection in a single run of percentages of transgenic maize as low as 0.054% of Bt11, 0.057% of T25, 0.036% of MON810, 0.064% of GA21, and 0.018% of Bt176 in flour obtaining signals still far from the detection limit (namely, the signal/noise ratios for the corresponding DNA peaks were 41, 124, 98, 250, 252, and 473, respectively). These percentages are well below the minimum threshold marked by the European Regulation for transgenic food labeling (i.e., 0.5-0.9%). A study on the reproducibility of the multiplex PCR-CGE-LIF procedure was also performed. Thus, values of RSD lower than 0.67 and 6.80% were obtained for migration times and corrected peak areas, respectively, for the same sample and three different days (n = 12). On the other hand, the reproducibility of the whole procedure, including four different multiplex PCR amplifications, was determined to be better than 0.66 and 23.3% for migration times and corrected peak areas, respectively. Agarose gel electrophoresis (AGE) and CGE-LIF were compared in terms of resolution and sensitivity for detecting PCR products, demonstrating that CGE-LIF can solve false positives induced by artifacts from the multiplex PCR reaction that could not be addressed by AGE. Moreover, CGE-LIF provides better resolution and sensitivity. To our knowledge

  20. Derivative spectrophotometric method for simultaneous determination of zofenopril and fluvastatin in mixtures and pharmaceutical dosage forms.

    Science.gov (United States)

    Stolarczyk, Mariusz; Maślanka, Anna; Apola, Anna; Rybak, Wojciech; Krzek, Jan

    2015-09-05

    Fast, accurate and precise method for the determination of zofenopril and fluvastatin was developed using spectrophotometry of the first (D1), second (D2), and third (D3) order derivatives in two-component mixtures and in pharmaceutical preparations. It was shown, that the developed method allows for the determination of the tested components in a direct manner, despite the apparent interference of the absorption spectra in the UV range. For quantitative determinations, "zero-crossing" method was chosen, appropriate wavelengths for zofenopril were: D1 λ=270.85 nm, D2 λ=286.38 nm, D3 λ=253.90 nm. Fluvastatin was determined at wavelengths: D1 λ=339.03 nm, D2 λ=252.57 nm, D3 λ=258.50 nm, respectively. The method was characterized by high sensitivity and accuracy, for zofenopril LOD was in the range of 0.19-0.87 μg mL(-1), for fluvastatin 0.51-1.18 μg mL(-1), depending on the class of derivative, and for zofenopril and fluvastatin LOQ was 0.57-2.64 μg mL(-1) and 1.56-3.57 μg mL(-1), respectively. The recovery of individual components was within the range of 100±5%. For zofenopril, the linearity range was estimated between 7.65 μg mL(-1) and 22.94 μg mL(-1), and for fluvastatin between 5.60 μg mL(-1) and 28.00 μg mL(-1). Copyright © 2015 Elsevier B.V. All rights reserved.

  1. Simultaneous Determination of 14 Phenolic Compounds in Grape Canes by HPLC-DAD-UV Using Wavelength Switching Detection

    Directory of Open Access Journals (Sweden)

    Ang Zhang

    2013-11-01

    Full Text Available The paper described a novel chromatographic method for the simultaneous determination of phenolic compounds such as gallic, protocatechuic, vanillic, caffeic, syringic, p-coumaric and salicylic acid, (+-catechin, (‒-epicatechin, rutin, morin, quercetin, coumarin and trans-resveratrol at their maximum absorbance wavelengths (MAW employing reverse-phase high performance liquid chromatography combined with DAD and UV detection via detection wavelength switching. The method was based on MAW acquisition by DAD and quantification by UV. The separation process was performed on a Shim-Pack VP-ODS C18 column (250 mm × 4.6 mm, 5 μm held at 30 °C, utilizing 3.0% acetic acid and acetonitrile as mobile phase at a flow rate of 0.8 mL/min in the gradient elution mode. The method was fully validated in terms of linearity (r2 > 0.9990, 10‒350 mg/L, precision (both intra-day and inter-day RSD < 4.22%, accuracy (97.31%‒104.66%, specificity, robustness (0.59% < RSD < 2.86%, limit of detection and quantification. The switching method significantly improved the sensitivities of most phenolics studied in comparison with the standard constant wavelength detection (280 nm. The proposed method has been successfully applied to the determination of 14 phenolic compounds in 89 varieties of one-year-old Chinese grape one-year-canes. Grape canes contain many phenolics, especially trans-resveratrol, (‒-epicatechin, and (+-catechin.

  2. A novel dual soil sensor for simultaneous water content and water potential determination in irrigation scheduling and environmental monitoring

    Science.gov (United States)

    Hübner, Christof; Spohrer, Klaus; Karaj, Shkelqim; Müller, Joachim

    2013-04-01

    Due to the climate change and decreasing water availability in many parts of the world, water efficient irrigation becomes more and more important to stabilize or even increase agricultural productivity. An efficient irrigation scheduling relies on soil water potential information in order to define the optimal irrigation start as well as on soil water content data to quantify the amount of soil water and thus to properly define irrigation depth. Furthermore, nutrient leaching and groundwater contamination will be reduced by controlled irrigation. Therefore, a novel dual soil sensor was developed which allows for simultaneous determination of water content and water potential at low costs suitable for distributed sensing. The soil water content measurement is realized with a dielectric measurement approach. Sensor elements are arranged on a printed circuit board, which can easily be inserted into the soil. Soil water potential data is deduced from water content measurements in porous matrices with known retention characteristics. The matrices are placed on the printed circuit board above a water content sensitive dielectric measuring area. In contrast to common granular matrix sensors, the matrices are characterized by a narrow pore size ranges by which the accuracy of soil water potential determination can be improved and a threshold characteristic suitable for irrigation is achieved. Sensor principle and laboratory experiments will be presented. For application in irrigation scheduling, the dual sensor is connected to off-the-shelf irrigation controllers by an additional interface controller. The interface controller activates moisture measurements of the sensor and compares the actual measurements with set-points of water content or water potential. The running time-based programme of the irrigation controller will be interrupted if measured soil water contents are above a predefined water content threshold or soil water potential measurements are below a

  3. Simultaneous determination of biotoxins DSP and AZAs in bivalve molluscs and fish by liquid chromatography/tandem mass spectrometry.

    Science.gov (United States)

    Zhuo, Liyang; Fu, Wusheng; Yang, Yiqiang; Qiu, Bin; Lin, Zhenyu; Shan, Liyang; Zheng, Lemin; Li, Jianrong; Chen, Guonan

    2014-07-15

    A method has been developed for simultaneous determination of the toxins OA, DTX-1, AZA-1, AZA-2 and AZA-3 in various aquatic products as these can cause diarrhoetic shellfish poisoning (DSP) in humans, an intoxication characterized by vomiting and diarrhea. Separation of the toxins was achieved on a C18 column (150 mm × 2.1 mm, 3.5 µm) using an acetonitrile/water gradient with formic acid as an eluent modifier. Electrospray ionisation (ESI) in negative mode was used to generate the molecule related ion [M-H](-), for OA and DTX-1, while ESI in positive mode was used to generate the molecule related ion [M+H](+) for AZAs. Samples were extracted with 80% methanol, followed by partitioning with ethyl acetate, purified on a Poly-Sery MAX cartridge and finally analyzed by LC/ESI-MS/MS in the multiple reaction monitoring (MRM) mode. The limit of detection (LOD) and limit of qualification (LOQ) of the method were in the range of 0.02-0.79 µg/kg and 0.07-2.64 µg/kg in Scomberomorus niphonius, blood clam and oyster, respectively, recoveries of the toxins at three fortification levels ranged from 71.3% to 104.8% with relative standard deviation from 1.0% to 12.5%. The calibration curves were well linear between the LC peak area of the selected ion pair and the concentration of the toxins, with the correlation coefficient over 0.99. The method was sufficiently sensitive to permit the determination of the toxins DSP and AZA in sea food. Copyright © 2014 John Wiley & Sons, Ltd.

  4. First liquid chromatography method for the simultaneous determination of levofloxacin, pazufloxacin, gatifloxacin, moxifloxacin and trovafloxacin in human plasma.

    Science.gov (United States)

    Sousa, Joana; Alves, Gilberto; Campos, Gonçalo; Fortuna, Ana; Falcão, Amílcar

    2013-07-01

    For the first time a simple, selective and sensitive liquid chromatography method was developed and validated for the simultaneous determination of levofloxacin (LEV), pazufloxacin (PAZ), gatifloxacin (GAT), moxifloxacin (MOX) and trovafloxacin (TRO) in human plasma. Samples were pre-treated with acetonitrile for precipitation of plasma proteins followed by evaporation and reconstitution steps. Chromatographic separation of the analytes and norfloxacin, used as internal standard (IS), was performed under gradient elution on a LiChroCART(®) Purospher Star C18 column (55mm×4mm, 3μm). The mobile phase comprised a mixture of 0.1% aqueous formic acid adjusted to pH 3.0 with triethylamine, acetonitrile and methanol pumped at a flow rate of 1.0mL/min. The detector was set at excitation/emission wavelengths of 260/455nm. Calibration curves were linear (r(2)≥0.9923) in the ranges of 0.005-5μg/mL for GAT, 0.02-5μg/mL for LEV, PAZ and MOX and 0.04-5μg/mL for TRO. The intra and interday precision did not exceed 7.32% and the intra and interday accuracy ranged from -11.73 to 8.92%. The limits of quantification were established at 0.005μg/mL for GAT, 0.02μg/mL for LEV, PAZ and MOX and 0.04μg/mL for TRO. No endogenous or tested exogenous compounds were found to interfere at the retention times of the analytes and IS. Since the proposed method proved to be reliable for the quantitative determination of LEV, PAZ, GAT, MOX and TRO it may be a useful tool for routine analysis and to support clinical pharmacokinetic and toxicological studies involving these antibiotics. Copyright © 2013 Elsevier B.V. All rights reserved.

  5. Simultaneous determination of triamcinolone acetonide and oxymetazoline hydrochloride in nasal spray formulations by HPLC.

    Science.gov (United States)

    Sudsakorn, Sirimas; Kaplan, Leonard; Williams, David A

    2006-03-18

    A high-performance liquid chromatography (HPLC) method with UV detection at 232 nm was developed and validated for the simultaneous determination of triamcinolone acetonide (TAA) and oxymetazoline hydrochloride (OXY) in nasal spray formulations. The chromatographic system consisted of a micro Bondapak CN column (150 mm x 3.9 mm), 5 microm particle size with a mobile phase composition of acetonitrile:ammonium acetate (pH 5.0, 20mM) (10:90, v/v) at a flow rate of 1.0 mL/min. Calibration curves were linear for both TAA and OXY in the concentration range of 2.5-25.0 microg/mL. The limit of detection and quantitation were 0.29 and 0.88 microg/mL for OXY and 0.24 and 0.73 microg/mL for TAA. The described method was further applied to the analysis and stability studies of two nasal spray formulations I and II prepared from TAA and OXY commercial nasal spray products. The stability of OXY and TAA in the commercial products and the nasal formulations I and II were analyzed after 30 days at room temperature and 30 days at 40 degrees C/60% relative humidity. The results of the stability study showed that OXY and TAA in the commercial nasal spray products and the nasal formulations I and II were stable at 20-25 degrees C (room temperature) but TAA was unstable at 40 degrees C/60% relative humidity. TAA exhibited more than 10% loss at 14 days in both the nasal formulations and in the commercial products. OXY showed increased degradation at 40 degrees C/60% relative humidity but <10%.

  6. Simultaneous determination of the lipoxygenase and hydroperxide lyase specificity in olive fruit pulp

    Directory of Open Access Journals (Sweden)

    Salas, Joaquín J.

    2000-06-01

    Full Text Available Olive pulp lipoxygenase regiospecificity and hydroperoxide lyase substrate specificity are important parameters in order to justify the volatile composition of olive oil. A new radiolabelling method to determine simultaneously these properties using only thin layer chromatography steps is described in the present work. The method involves incubation of an enzyme preparation from olive pulp with radiolabelled linoleate, followed by the fractionation of the resulting lipid products, previously treated with 2,4-dinitrophenyl hydrazine, on thin layer chromatography plates coated with polyethylenglycol 400. The results obtained are in agreement with previous studies carried out by other methods.La regioespecificidad de la lipoxigenasa y la especificidad del sustrato hidroperóxido liasa de pulpa de aceituna son parámetros importantes en la justificación de la composición en volátiles del aceite de oliva. En este trabajo se describe un nuevo método de marcaje radioactivo para determinar simultáneamente estas propiedades, usando solo etapas de cromatografía en capa fina. El método implica la incubación de una preparación enzimática de pulpa de aceituna con linoleato marcado, seguido del fraccionamiento de los productos lipídicos resultantes, previamente tratados con 2,4-dinitrofenil hidrazina, sobre placas de cromatografía en capa fina soportadas con polietilenglicol 400. Los resultados obtenidos están de acuerdo con estudios previos llevados a cabo con otros métodos.

  7. Simultaneous determination of nine phytohormones in seaweed and algae extracts by HPLC-PDA.

    Science.gov (United States)

    Górka, Bogusława; Wieczorek, Piotr P

    2017-07-01

    An RP-HPLC-PDA method for the simultaneous analysis of 9 compounds deriving from the phytohormones class was developed and optimized, namely indoleacetic acid (IAA), indolebutyric acid (IBA), phenyleacetic acid (PAA), naphtyleacetic acid (NAA), trans-zeatin (TZ), kinetin (KA), isopentenyladenine (IA), 6-benzylaminopurine (6-BA) and abscisic acid (ABA). Validation of the method was performed on the SFE-CO 2 extract made out of the mixture of Baltic algae. The regression coefficients for plant hormones were in the range from 0.997 to 0.999. The LOD and LOQ were on the levels from 0.05-0.29 and 0.15-0.88mg/L, respectively. Developed method was used for the separation and determination plant hormones in extracts obtained by SFE-CO 2 (supercritical fluid extraction) made out of the mixture of Baltic algae, Cladophora glomerata and Spirulina sp. In the extract of Baltic seaweed 2 of tested compounds were present in the concentration of 154,45±20,63μg/g for TZ and 362,47±13,00μg/g for PAA, whereas in Cladophora glomerata extract contained PAA and IAA in the concentration of 229,30±7,90μg/g and 23,91±0,80μg/g, respectively (all values per g of extract). The differences in the hormones levels may occur due to the different scale of extract preparation (laboratory or industrial) and other factors like the place of algae collection, year of collection or the way of biomass preparation. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Micellar nanotubes dispersed electrokinetic chromatography for the simultaneous determination of antibiotics in bovine milk.

    Science.gov (United States)

    Springer, Valeria H; Lista, Adriana G

    2012-07-01

    A method to determine four antibiotics for veterinary use (ciprofloxacin, enrofloxacin, florfenicol, and chloramphenicol) of different families (fluoroquinolones and amphenicols) in bovine milk was developed. The determination of the analytes was carried out using micellar electrokinetic capillary chromatography (MEKC) with a common sodium borate-SDS buffer solution containing single-walled carbon nanotubes (SWCNTs). In this way, a great improvement in the electrophoretic resolution and the separation efficiency was achieved compared to MEKC. An online reverse electrode polarity-stacking mode (REPSM) was carried out to enhance sensitivity. This step was performed in only 2 min and it allowed a stacked percentage of 103. That means that all the amount of injected analytes is effectively stacked. When this stacking procedure was combined with an off-line preconcentration step, based on SPE, analytes could be detected in lower concentration than the established maximum residue limits (MRLs). The LODs for the four compounds were between 6.8 and 13.8 μg L(-1) and the RSD values were between 1.1% and 6.6%. The whole method was applied to spiked real samples with acceptable precision and satisfactory recoveries. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Electrochemical behaviors and simultaneous determination of guanine and adenine based on graphene–ionic liquid–chitosan composite film modified glassy carbon electrode

    International Nuclear Information System (INIS)

    Niu Xiuli; Yang Wu; Ren Jie; Guo Hao; Long Shijia; Chen Jiaojiao; Gao Jinzhang

    2012-01-01

    Highlights: ► This work developed a novel electrochemical biosensors for guanine and adenine detection simultaneously. ► A disposable electrode based on graphene sheets, ionic liquid and chitosan was proposed. ► The presented method was also applied to simultaneous determination of guanine and adenine in denatured DNA samples with satisfying results. ► Easy fabrication, high sensitivity, excellent reproducibility and long-term stability. - Abstract: A graphene sheets (GS), ionic liquid (IL) and chitosan (CS) modified electrode was fabricated and the modified electrode displayed excellent electrochemical catalytic activities toward guanine and adenine. The transfer electron number (n) and the charge transfer coefficient (α) were calculated with the result as n = 2, α = 0.58 for guanine, and n = 2, α = 0.51 for adenine, which indicated the electrochemical oxidation of guanine and adenine on GS/IL/CS modified electrode was a two-electron and two-proton process. The oxidation overpotentials of guanine and adenine were decreased significantly compared with those obtained at the bare glassy carbon electrode and multi-walled carbon nanotubes modified electrode. The modified electrode exhibited good analytical performance and was successfully applied for individual and simultaneous determination of guanine and adenine. Low detection limits of 0.75 μM for guanine and 0.45 μM for adenine were obtained, with the linear calibration curves over the concentration range 2.5–150 μM and 1.5–350 μM, respectively. At the same time, the proposed method was successfully applied for the determination of guanine and adenine in denatured DNA samples with satisfying results. Moreover, the GS/IL/CS modified electrode exhibited good sensitivity, long-term stability and reproducibility for the determination of guanine and adenine.

  10. Electrochemical Behavior of Catechol and Hydroquinone at Copper Doped Poly (Methyl Red Coated Hydroxyl Multiwalled Carbon Nanotube Film and Their Simultaneous Determination in Water Samples

    Directory of Open Access Journals (Sweden)

    Ying Zhang

    2014-09-01

    Full Text Available A glassy carbon electrode modified with copper doped poly (methyl red coated hydroxyl multiwalled carbon nanotube film (Cu-PMR/MWCNTs, was developed to serve as a sensor for simultaneous determination of Hydroquinone (HQ and catechol (CC in this paper. The fabricated electrode showed excellent electrocatalytic behaviors towards the oxidation of HQ and CC with the enhancement of the redox peak current and the decrease of the peak-to-peak separation. Under the optimized condition, the individual determination of HQ or CT in their mixtures was performed, the response peak currents of the modified electrodes were linear over ranges of 8.0´10-7~4.0´10-4 M (R2=0.999 for CT and 5.0´10-7~2.0´10-4 M (R2=0.993 for HQ. The sensor also exhibited good sensitivity with the detection limit of 1.0´10-8 mol/L and 5.0´10-8 mol/L for HQ and CT, respectively. The simultaneous determination of HQ and CC was demonstrated by simultaneously changing their concentrations. The reduction peak currents of HQ and CC increased linearly with the concentration of their own in the range of 8´10-7 and 2.0´10-4 M for HQ and CC, with correlation coefficients of 0.994 and 0.995 (S/N=3, respectively. This study provides a new kind of composite modified electrode for electrochemical sensors with good selectivity and strong anti-interference. It has been applied to simultaneous determination of HQ and CT in water sample with high selectivity.

  11. Determining Confounding Sensitivities In Eddy Current Thin Film Measurements

    Energy Technology Data Exchange (ETDEWEB)

    Gros, Ethan; Udpa, Lalita; Smith, James A.; Wachs, Katelyn

    2016-07-01

    Determining Confounding Sensitivities In Eddy Current Thin Film Measurements Ethan Gros, Lalita Udpa, Electrical Engineering, Michigan State University, East Lansing MI 48824 James A. Smith, Experiment Analysis, Idaho National Laboratory, Idaho Falls ID 83415 Eddy current (EC) techniques are widely used in industry to measure the thickness of non-conductive films on a metal substrate. This is done using a system whereby a coil carrying a high-frequency alternating current is used to create an alternating magnetic field at the surface of the instrument's probe. When the probe is brought near a conductive surface, the alternating magnetic field will induce ECs in the conductor. The substrate characteristics and the distance of the probe from the substrate (the coating thickness) affect the magnitude of the ECs. The induced currents load the probe coil affecting the terminal impedance of the coil. The measured probe impedance is related to the lift off between coil and conductor as well as conductivity of the test sample. For a known conductivity sample, the probe impedance can be converted into an equivalent film thickness value. The EC measurement can be confounded by a number of measurement parameters. It is the goal of this research to determine which physical properties of the measurement set-up and sample can adversely affect the thickness measurement. The eddy current testing is performed using a commercially available, hand held eddy current probe (ETA3.3H spring loaded eddy probe running at 8 MHz) that comes with a stand to hold the probe. The stand holds the probe and adjusts the probe on the z-axis to help position the probe in the correct area as well as make precise measurements. The signal from the probe is sent to a hand held readout, where the results are recorded directly in terms of liftoff or film thickness. Understanding the effect of certain factors on the measurements of film thickness, will help to evaluate how accurate the ETA3.3H spring

  12. Validation of an HPLC method for the simultaneous determination of eletriptan and UK 120.413

    Directory of Open Access Journals (Sweden)

    LJILJANA ZIVANOVIC

    2006-11-01

    Full Text Available Arapid and sensitive RPHPLCmethod was developed for the routine control analysis of eletriptan hydrobromide and its organic impurity UK 120.413 in Relpax® tablets. The chromatography was performed at 20 °Cusing a C18 XTerraTM (5 m, 150 × 4,6 mm column at a flow rate 1.0 ml/min. The drug and its impurity were detected at 225 nm. The mobile phase consisted of TEA (1 % – methanol (67.2:32.8 v/v, the pH of which was adjusted to 6.8 with 85 % orthophosphoric acid. Quantification was accomplished by the internal standard method. The developed RP HPLC method was validated by testing: accuracy, precision, repeatibility, specificity, detection limit, quantification limit, linearity, robustness and sensitivity. High linearity of the analytical procedure was confirmed over the concentration range of 0.05 – 1.00 mg/ml for eletriptan hydrobromide and from 0.10 – 1.50 µg/ml for UK 120.413, with correlation coefficients greater than r = 0.995. The low value of the RSD expressed the good repeatability and precision of the method. Experimental design and a response surface method were used to test robustness of the analytical procedure and to evaluate the effect of variation of the method parameters, namely the mobile phase composition, pH and temperature. They showed small deviations from the method setting. The good recovery and low RSD confirm the suitability of the proposed RP HPLC method for the routine determination of eletriptan hydrobromide and its impurity UK 120.413 in Relpax® tables.

  13. A method to simultaneously determining the reduction in PAH dissolved concentrations and bioaccessibility in carbon amended soils

    DEFF Research Database (Denmark)

    Marchal, Geoffrey; Smith, Kilian E. C.; Rein, Arno

    In order to investigate the potential of different soil amendments (activated charcoal (AC), charcoal (biochar), compost) to sorb PAHs and their effect on bioaccessibility and biodegradation of PAHs in soil, a method was developed that can determine simultaneously the changes in PAH dissolved...

  14. Simultaneous voltammetric determination of paracetamol and caffeine in pharmaceutical formulations using a boron-doped diamond electrode.

    Science.gov (United States)

    Lourenção, Bruna Cláudia; Medeiros, Roberta Antigo; Rocha-Filho, Romeu C; Mazo, Luiz Henrique; Fatibello-Filho, Orlando

    2009-05-15

    A simple and highly selective electrochemical method was developed for the single or simultaneous determination of paracetamol (N-acetyl-p-aminophenol, acetaminophen) and caffeine (3,7-dihydro-1,3,7-trimethyl-1H-purine-2,6-dione) in aqueous media (acetate buffer, pH 4.5) on a boron-doped diamond (BDD) electrode using square wave voltammetry (SWV) or differential pulse voltammetry (DPV). Using DPV with the cathodically pre-treated BDD electrode, a separation of about 550 mV between the peak oxidation potentials of paracetamol and caffeine present in binary mixtures was obtained. The calibration curves for the simultaneous determination of paracetamol and caffeine showed an excellent linear response, ranging from 5.0 x 10(-7)mol L(-1) to 8.3 x 10(-5)mol L(-1) for both compounds. The detection limits for the simultaneous determination of paracetamol and caffeine were 4.9 x 10(-7)mol L(-1) and 3.5 x 10(-8)mol L(-1), respectively. The proposed method was successfully applied in the simultaneous determination of paracetamol and caffeine in several pharmaceutical formulations (tablets), with results similar to those obtained using a high-performance liquid chromatography method (at 95% confidence level).

  15. Simultaneous determination of gene expression and bacterial identity in single cells in defined mixtures of pure cultures

    DEFF Research Database (Denmark)

    Poulsen, Lars K.; Dalton, Helen M.; Angels, Mark

    1997-01-01

    A protocol was developed to achieve the simultaneous determination of gene expression and bacterial identity at the level of single cells: a chromogenic beta-galactosidase activity assay was combined with in situ hybridization of Fluorescently labelled oligonucleotide probes to rRNA. The method...... allows monitoring of gene expression and quantification of beta-galactosidase activity in single cells....

  16. Simultaneous determination of estrogens and progestogens in honey using high performance liquid chromatography-tandem mass spectrometry

    Science.gov (United States)

    This work describes the development and validation of a method for the simultaneous determination of 13 estrogens and progestogens in honey by high performance liquid chromatography-tandem mass spectrometry. The target compounds were preconcentrated by solid phase extraction. Pretreatment variables ...

  17. Sequential Injection Method for Rapid and Simultaneous Determination of 236U, 237Np, and Pu Isotopes in Seawater

    DEFF Research Database (Denmark)

    Qiao, Jixin; Hou, Xiaolin; Steier, Peter

    2013-01-01

    An automated analytical method implemented in a novel dual-column tandem sequential injection (SI) system was developed for simultaneous determination of 236U, 237Np, 239Pu, and 240Pu in seawater samples. A combination of TEVA and UTEVA extraction chromatography was exploited to separate and purify...

  18. Determination of a lower bound on Earth's climate sensitivity

    Directory of Open Access Journals (Sweden)

    STEPHEN E. Schwartz

    2013-09-01

    Full Text Available Transient and equilibrium sensitivity of Earth's climate has been calculated using global temperature, forcing and heating rate data for the period 1970–2010. We have assumed increased long-wave radiative forcing in the period due to the increase of the long-lived greenhouse gases. By assuming the change in aerosol forcing in the period to be zero, we calculate what we consider to be lower bounds to these sensitivities, as the magnitude of the negative aerosol forcing is unlikely to have diminished in this period. The radiation imbalance necessary to calculate equilibrium sensitivity is estimated from the rate of ocean heat accumulation as 0.37±0.03 W m−2 (all uncertainty estimates are 1−σ. With these data, we obtain best estimates for transient climate sensitivity 0.39±0.07 K (W m−2−1 and equilibrium climate sensitivity 0.54±0.14 K (W m−2−1, equivalent to 1.5±0.3 and 2.0±0.5 K (3.7 W m−2−1, respectively. The latter quantity is equal to the lower bound of the ‘likely’ range for this quantity given by the 2007 IPCC Assessment Report. The uncertainty attached to the lower-bound equilibrium sensitivity permits us to state, within the assumptions of this analysis, that the equilibrium sensitivity is greater than 0.31 K (W m−2−1, equivalent to 1.16 K (3.7 W m−2−1, at the 95% confidence level.

  19. Simultaneous determination of Rn-220 and Rn-222 concentrations in atmospheres by cellulose nitrate ionographic detectors

    International Nuclear Information System (INIS)

    Lobao, N.

    1977-01-01

    A method for the indoor determination of airborne radon and radon daughters is described, based in the utilization of cellulose nitrate (CN) ionographic detectors (LR-115-Kodak-Pathe) These track-etching detectors are coupled to an air sample and to a difusion chamber respectively. In the first system ambient air is pulled through a fiber glass filter for collection of airborne radon daughters (Flow: 230 ml/min). In the second system, the cellulose nitrate detectors is coupled/min). In the second system, the cellulose nitrate detectors is coupled to a difusion chamber electrostatic precipitator arrangement. Here the CN detector will register only the alpha particles given off by the decay products of Rn-222 formed within the sensitive volume of electrostatic precipitator. The construction of calibration curves for the two systems using adequate steady-state concentrations of Rn-220 and Rn-222 in an exposure chamber (1 cubic meter), will allow the use of the system for measurement of measurement of averaged integrated radon concentrations. The CN attached to the CN attached to the air sampler is exposed in the reference atmosphere with and without a mylar filter for discrimination of alpha particles with different energies Field sampling indicated however, that efficiency of the two systems are still low for the measurement of environmental levels of Rn-220 and Rn-222 within houses of the AENR, recommendations for efficienty improvement of the system are proposed [pt

  20. [Simultaneous determination of clevidipine butyrate and its metabolite clevidipine acid in dog blood by liquid chromatography-tandem mass spectrometry].

    Science.gov (United States)

    Wei, Hui-hui; Gu, Yuan; Liu, Yan-ping; Wei, Guang-li; Chen, Yong; Liu, Chang-xiao; Si, Duan-yun

    2015-10-01

    A rapid, sensitive and simple liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for the simultaneous determination of clevidipine butyrate and its primary metabolite clevidipine acid in dog blood. After one-step protein precipitation with methanol, the chromatographic separation was carried out on an Ecosil C18 column (150 mm x 4.6 mm, 5 µm) with a gradient mobile phase consisting of methanol and 5 mmol · L(-1) ammonium formate. A chromatographic total run time of 13.0 min was achieved. The quantitation analysis was performed using multiple reaction monitoring (MRM) at the specific ion transitions of m/z 454.1 [M-H]- --> m/z 234.1 for clevidipine butyrate, m/z 354.0 [M-H]- --> m/z 208.0 for clevidipine acid and m/z 256.1 [M-H]- --> m/z 227.1 for elofesalamide (internal standard, IS) in the negative ion mode with electrospray ionization (ESI) source. The linear calibration curves for clevidipine butyrate and clevidipine acid were obtained in the concentration ranges of 0.5-100 ng · mL and 1-200 ng · mL(-1), separately. The lower limit of quantification of clevidipine butyrate and clevidipine acid were 0.5 ng · mL(-1) and 1 ng · mL(-1). The intra and inter-assay precisions were all below 12.9%, the accuracies were all in standard ranges. Stability testing indicated that clevidipine butyrate and clevidipine acid in dog blood with the addition of denaturant methanol was stable under various processing and/or handling conditions. The validated method has been successfully applied to a pharmacokinetic study of clevidipine butyrate injection to 8 healthy Beagle dogs following intravenous infusion at a flow rate of 5 mg · h(-1) for 0.5 h.

  1. Application and validation of superior spectrophotometric methods for simultaneous determination of ternary mixture used for hypertension management

    Science.gov (United States)

    Mohamed, Heba M.; Lamie, Nesrine T.

    2016-02-01

    Telmisartan (TL), Hydrochlorothiazide (HZ) and Amlodipine besylate (AM) are co-formulated together for hypertension management. Three smart, specific and precise spectrophotometric methods were applied and validated for simultaneous determination of the three cited drugs. Method A is the ratio isoabsorptive point and ratio difference in subtracted spectra (RIDSS) which is based on dividing the ternary mixture of the studied drugs by the spectrum of AM to get the division spectrum, from which concentration of AM can be obtained by measuring the amplitude values in the plateau region at 360 nm. Then the amplitude value of the plateau region was subtracted from the division spectrum and HZ concentration was obtained by measuring the difference in amplitude values at 278.5 and 306 nm (corresponding to zero difference of TL) while the total concentration of HZ and TL in the mixture was measured at their isoabsorptive point in the division spectrum at 278.5 nm (Aiso). TL concentration is then obtained by subtraction. Method B; double divisor ratio spectra derivative spectrophotometry (RS-DS) and method C; mean centering of ratio spectra (MCR) spectrophotometric methods. The proposed methods did not require any initial separation steps prior the analysis of the three drugs. A comparative study was done between the three methods regarding their; simplicity, sensitivity and limitations. Specificity was investigated by analyzing the synthetic mixtures containing different ratios of the three studied drugs and their tablets dosage form. Statistical comparison of the obtained results with those found by the official methods was done, differences were non-significant in regard to accuracy and precision. The three methods were validated in accordance with ICH guidelines and can be used for quality control laboratories for TL, HZ and AM.

  2. Simultaneous determination of moxifloxacin and ofloxacin in physiological fluids using high performance liquid chromatography with ultraviolet detection.

    Science.gov (United States)

    Khan, Fahim Ullah; Nasir, Fazli; Iqbal, Zafar; Khan, Ismail; Shahbaz, Naila; Hassan, Muhammad; Ullah, Farhad

    2016-04-01

    A novel, sensitive and validated RP-HPLC-UV method was developed for simultaneous determination of moxifloxacin and ofloxacin using timolol maleate as internal standard in physiological fluids. Different experimental parameters were optimized and validated according to international guidelines. Complete separation of the analytes was achieved with Kromasil 100-5C18 analytical column (250mm×4.6mm×5μm), methanol and 0.05% trifloroacetic acid (TFA) (38:62v/v) were used as mobile phase, pumped at flow rate of 1.1ml/min in isocratic phase, column oven temperature maintained at 45°C and detection wavelength of 290nm. Protein precipitation method was applied to extract the drugs from human plasma and bovine aqueous humor samples using methanol as precipitating solvent. This method is linear in concentration range of 0.018-100μg/ml for moxifloxacin and 0.014-20μg/ml for ofloxacin. The recoveries of the method were 97.52 and 97.39% in human plasma for MX and OFN respectively, while in aqueous humor 94.48% for MX. The LOD values in plasma were found to be 10.0 and 8.00ng/ml for MX and OFN respectively, while their respective LOQ values were 18.0 and 14ng/ml. In aqueous humor the LOD and LOQ for MX were 16.0 and 24ng/ml respectively. In future, this method will be used to study the pharmacokinetic profile of moxifloxacin and ofloxacin in biological fluids and pharmaceutical products. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. Simultaneous determination of ribavirin and ribavirin base in monkey plasma by high performance liquid chromatography with tandem mass spectrometry.

    Science.gov (United States)

    Li, Wenkui; Luo, Suyi; Li, Shaoyong; Athill, Lawrence; Wu, Amy; Ray, Tapan; Zhou, Wei; Ke, June; Smith, Harold T; Tse, Francis L S

    2007-02-01

    For the first time, a liquid chromatographic method with tandem mass spectrometric detection (LC-MS/MS) for the simultaneous determination of ribavirin and rabavirin base was developed and validated over the concentration range of 10-5,000 ng/ml, respectively, using a 0.025 ml monkey plasma sample. Ribavirin, ribavirin base, and the internal standards were extracted from monkey plasma via protein precipitation. After evaporation of the supernatant, the extract was reconstituted with 5% methanol (containing 0.1% formic acid) and injected onto the LC-MS/MS system. Optimum chromatographic separation was achieved on a Waters Atlantis dc18 (150 mm x 2.1mm, 5 microm) column with mobile phase run in gradient with 100% water containing 0.5% formic acid (A) and 90% acetonitrile (containing 0.5% formic acid (B). The flow rate was 0.4-0.6 ml/min with total cycle time of approximately 7.0 min. Post-column addition of acetonitrile (containing 0.1% formic acid) at 0.3 ml/min was used to increase the ionization efficiency in the MS source. The method was validated for sensitivity, linearity, reproducibility, stability and recovery. Lack of adverse matrix effect and carry-over was also demonstrated. The intra-day and inter-day precision and accuracy of the quality control (QC) samples were <9.0% relative standard deviation (R.S.D.) and 10.8% bias for ribavirin, and 10.3% R.S.D. and 11.3% bias for ribavirin base. The current specific, accurate and precise assay is useful in support of the toxicokinetic and pharmacokinetic studies of these compounds.

  4. Electrocatalytic properties of functionalized carbon nanotubes with titanium dioxide and benzofuran derivative/ionic liquid for simultaneous determination of isoproterenol and serotonin

    International Nuclear Information System (INIS)

    Mazloum-Ardakani, Mohammad; Khoshroo, Alireza

    2014-01-01

    Highlights: • TiO 2 and benzofuran derivative were uniformly deposited onto carbon nanotubes • This nanocomposite can be used as a sensor in isoproterenol detection • This sensor shows a great enhancement in sensitivity, selectivity and stability - Abstract: In this paper we report synthesis and application of functionalized multiwalled carbon nanotubes (CNTs) with titanium dioxide nanoparticles (TiO 2 ), 9-(1,3-dithiolan-2-yl)-6,7-dihydroxy-3,3-dimethyl-3,4-dihydrodibenzo[b,d] furan-1(2H)-one (benzofuran derivative (DDF)) and 1-butyl-3-methylimidazolium tetrafluoroborate (IL) as high sensitive sensors for simultaneous determination of isoproterenol (IP) and serotonin (5-HT) using glassy carbon electrode. The modified electrode was characterized by different methods including a scanning electron microscope (SEM), electrochemical impedance spectroscopy (EIS) and voltammetry. A pair of well-defined redox peaks of DDF was obtained at the modified glassy carbon electrode by direct electron transfer between the DDF and the electrode. Dramatically enhanced electrocatalytic activity was exemplified at the modified electrode, as an electrochemical sensor to study the electro oxidation of IP and 5-HT. The differential pulse voltammetry data showed that the obtained anodic peak currents were linearly dependent on the IP and 5-HT concentrations in the range of 0.1–1300.0 and 1.0–650.0 μM, respectively. The applicability of the modified electrode was demonstrated by simultaneous determination of IP and 5-HT in human serum

  5. Rapid Multisample Analysis for Simultaneous Determination of Anthropogenic Radionuclides in Marine Environment

    DEFF Research Database (Denmark)

    Qiao, Jixin; Shi, Keliang; Hou, Xiaolin

    2014-01-01

    of simultaneous preconcentration of all target radionuclides. Technetium was separated from the actinides via valence control of technetium (as Tc(VII)) in a ferric hydroxide coprecipitation. A novel preseparation protocol between uranium and neptunium/plutonium fractions was developed based on the observation...

  6. Simultaneous determination of Δ9-tetrahydrocannabinol and 11-nor-9-carboxy-Δ9-tetrahydrocannabinol in oral fluid using isotope dilution liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    Lee, Pin Duo; Chang, Yuan-Jhe; Lin, Keh-Liang; Chang, Yan-Zin

    2012-01-01

    The detection and confirmation of cannabinoids in oral fluid are important in forensic toxicology. Currently, the presence of Δ(9)-tetrahydrocannabinol (THC) is used for the detection of cannabis in oral fluid. A low concentration of 11-nor-9-carboxy-Δ(9)-tetrahydrocannabinol (THC-COOH) is found in oral fluid, which suggested a convenient and low-sensitivity confirmation assay can be used in a routine forensic laboratory. In this study, a highly sensitive isotope dilution liquid chromatography-tandem mass spectrometry method following dansylation was successfully developed for simultaneous determination of THC and THC-COOH in oral fluid. The dansylated derivatives dramatically demonstrated and enhanced the sensitivity of THC and THC-COOH. To avoid signal influenced by the matrix, a 5-min liquid chromatography gradient program was evaluated and optimized, which reduced the sample diffusion and caused sharp peaks (less than 12 s) and thus helped to achieve detection at a low level. The sensitivity, accuracy, and precision were also evaluated, and high quantitative accuracy and precision were obtained. The limit of quantitation of this approach was 25 pg/mL for THC and 10 pg/mL for THC-COOH in oral fluid. Finally, the method was successfully applied to eight suspected cannabis users. Among them, in six oral fluid samples THC-COOH was determined at a concentration from 13.1 to 47.2 pg/mL.

  7. Sampling and simultaneous determination of volatile per- and polyfluoroalkyl substances in wastewater treatment plant air and water.

    Science.gov (United States)

    Dimzon, Ian Ken; Westerveld, Joke; Gremmel, Christoph; Frömel, Tobias; Knepper, Thomas P; de Voogt, Pim

    2017-02-01

    Volatile per- and polyfluoroalkyl substances (PFASs) are often used as precursors in the synthesis of nonvolatile PFASs. The volatile PFASs, which include the perfluoroalkyl iodides (PFAIs), fluorotelomer iodides (FTIs), fluorotelomer alcohols (FTOHs), fluorotelomer olefins (FTOs), fluorotelomer acrylates (FTACs), and fluorotelomer methacrylates (FTMACs), are often produced starting from the telomerization process. These volatile compounds can be present in the air and water environment and can be transformed into highly persistent perfluoroalkyl carboxylic acids. With the exception of FTOHs, which are well studied, the determination of other volatile PFASs is also of prime importance in studying the sources and fate of PFASs. In this study, a method was developed to determine representative precursor compounds that included PFAIs, FTIs, FTOs, FTACs, and FTMACs in wastewater treatment plant (WWTP) air and water samples. The sampling and sample preparation step involved the use of solid-phase extraction (SPE) cartridges with HLB™ material to enrich the analyte. Gas chromatography with mass spectrometry was employed for the detection and quantification of the analytes. Method validation results showed high linearity and sensitivity in the positive electron ionization-selected ion monitoring mode (+EI-SIM). The absolute instrumental limits of detection were in the range of 0.5 to 2 pg. The method detection limit (MDL) in air was 1 ng/m 3 with the exception of the FTACs which could be only be detected at concentrations higher than 40 ng/m 3 . The MDL in water was 10 ng/L. Direct spiking of the cartridges and analyte introduction by volatilization from the glass surface onto the SPE material had recoveries between 86 and 100%. The volatile PFASs were shown to readily partition into the air rather than into water. Consequently, large losses in the amount of PFASs were observed when these were spiked into the water. Graphical abstract Wastewater treatment plant air

  8. How to Determine the Increasing Returns Sensitivity of Your Industry?

    NARCIS (Netherlands)

    M.H. Klein (Martin); E. den Hartigh; H.R. Commandeur (Harry); F. Langerak (Fred)

    2004-01-01

    textabstractIncreasing returns means that self-reinforcing mechanisms are at work within firms and markets. These mechanisms come in four forms: scale effects, learning effects, network effects and social interaction effects. Some industries are more sensitive to increasing returns than others. It

  9. Simultaneous determination of lead, cadmium and zinc in Metro Manila air particulates by anodic stripping voltammetry

    International Nuclear Information System (INIS)

    Castaneda, Soledad S.

    1999-02-01

    Air particulate samples were collected from two monitoring stations in Metro Manila using a 'Gent' type dichotomous sampler for pollutant source apportionment studies. Samples were collected in two fractions: a fine fraction with aerodynamic diameter, d p p 3 : HCL: HF, 4: 1: 1) for at least 20 minutes with subsequent heating at lower power settings for a total of 20 minutes more, effectively decomposed the sample with complete recovery of the elements. The digests were evaporated to near dryness to eliminate the troublesome effect of HF and HNO 3 and to decrease acidity of the electrolytic solution to pH ≥ 2. At pH 2, the addition of at least 0.01 M KCl was needed to improve sensitivity. The formation of Zn-Cu intermetallic compounds which interfered in the accurate quantitation of zinc was eliminated by addition of gallium as a 'third' element. The amount of gallium needed varied from sample to sample and was affected by the pH of the solution. The DPASV parameters found to be optimum for the analysis of the air particulate samples are as follows: pulse amplitude, 50 mV; scan rate, 10 mV/sec; E dep , - 1.30 V; t dep , 2 min; and RDE rotation rate, 1500 rpm. Detection limits of 0.2 ppb for zinc, 0.6 ppb for lead, and 0.05 ppb for cadmium in the sample matrix were obtained. The standard addition method was found to be reliable for the quantitative determination of the analytes in the sample. All R 2 values obtained were > 0.9900 at 95% confidence level. Validation of the established analytical methodology by analyzing certified reference standards and performing parallel analysis by GF-AAS and flame AAS showed acceptable accuracy of the DPASV measurements. (Author)

  10. A Localized Surface Plasmon Resonance Sensing Method for Simultaneous Determination of Atenolol and Amiloride in Pharmaceutical Dosage Forms and Urine Samples

    Directory of Open Access Journals (Sweden)

    Marwa R. El-Zahry

    2018-01-01

    Full Text Available This contribution describes a simple, fast, and sensitive application of localized surface plasmon resonance effect of silver nanoparticles for simultaneous determination of antihypertensive drugs’ mixture atenolol and amiloride in both pharmaceutical dosage forms and in biological samples (urine. Silver nanoparticles were prepared by chemical reduction of silver nitrate using hydroxylamine HCL in an alkaline medium. Application of silver-hydroxylamine nanoparticles (SH NPs provides many advantages including reproducibility, sensitivity, and cost effective way of analyte determination. Amiloride has four amino groups which act as attachment points on the surface of silver nanoparticles resulting in a synergistic effect on the absorption intensity of atenolol, leading to increase the sensitivity of the determination of both compounds. This method shows excellent advantages comparing with the previously reported methods, including accuracy, precision, and selectivity. The linear range of atenolol is 1 × 10−5–1 × 10−4 mol·L−1 and of amiloride is 1 × 10−6–1 × 10−5 mol·L−1. The limit of detection (LOD values of atenolol and amiloride are 0.89 × 10−5 and 0.42 × 10−6 mol·L−1, respectively.

  11. Atom localization and center-of-mass wave-function determination via multiple simultaneous quadrature measurements

    International Nuclear Information System (INIS)

    Evers, Joerg; Qamar, Shahid; Zubairy, M. Suhail

    2007-01-01

    We discuss localization and center-of-mass wave-function measurement of a quantum particle using multiple simultaneous dispersive interactions of the particle with different standing-wave fields. In particular, we consider objects with an internal structure consisting of a single ground state and several excited states. The transitions between ground and the corresponding excited states are coupled to the light fields in the dispersive limit, thus giving rise to a phase shift of the light field during the interaction. We show that multiple simultaneous measurements allow both an increase in the measurement or localization precision in a single direction and the performance of multidimensional measurements or localization. Further, we show that multiple measurements may relax the experimental requirements for each individual measurement

  12. A novel bi-enzyme electrochemical biosensor for selective and sensitive determination of methyl salicylate.

    Science.gov (United States)

    Fang, Yi; Umasankar, Yogeswaran; Ramasamy, Ramaraja P

    2016-07-15

    An amperometric sensor based on a bi-enzyme modified electrode was fabricated to detect methyl salicylate, a volatile organic compound released by pathogen-infected plants via systemic response. The detection is based on cascadic conversion reactions that result in an amperometric electrochemical signal. The bi-enzyme electrode is made of alcohol oxidase and horseradish peroxidase enzymes immobilized on to a carbon nanotube matrix through a molecular tethering method. Methyl salicylate undergoes hydrolysis to form methanol, which is consumed by alcohol oxidase to form formaldehyde while simultaneously reducing oxygen to hydrogen peroxide. The hydrogen peroxide will be further reduced to water by horseradish peroxidase, which results in an amperometric signal via direct electron transfer. The bi-enzyme biosensor was evaluated by cyclic voltammetry and constant potential amperometry using hydrolyzed methyl salicylate as the analyte. The sensitivity of the bi-enzyme biosensor as determined by cyclic voltammetry and constant potential amperometry were 112.37 and 282.82μAcm(-2)mM(-1) respectively, and the corresponding limits of detection were 22.95 and 0.98μM respectively. Constant potential amperometry was also used to evaluate durability, repeatability and interference from other compounds. Wintergreen oil was used for real sample study to establish the application of the bi-enzyme sensor for selective determination of plant pathogen infections. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Simultaneous Voltammetric/Amperometric Determination of Sulfide and Nitrite in Water at BDD Electrode

    Directory of Open Access Journals (Sweden)

    Anamaria Baciu

    2015-06-01

    Full Text Available This work reported new voltammetric/amperometric-based protocols using a commercial boron-doped diamond (BDD electrode for simple and fast simultaneous detection of sulfide and nitrite from water. Square-wave voltammetry operated under the optimized working conditions of 0.01 V step potential, 0.5 V modulation amplitude and 10 Hz frequency allowed achieving the best electroanalytical parameters for the simultaneous detection of nitrite and sulfide. For practical in-field detection applications, the multiple-pulsed amperometry technique was operated under optimized conditions, i.e., −0.5 V/SCE for a duration of 0.3 s as conditioning step, +0.85 V/SCE for a duration of 3 s that assure the sulfide oxidation and +1.25 V/SCE for a duration of 0.3 s, where the nitrite oxidation occurred, which allowed the simultaneously detection of sulfide and nitrite without interference between them. Good accuracy was found for this protocol in comparison with standardized methods for each anion. Also, no interference effect was found for the cation and anion species, which are common in the water matrix.

  14. Identifying Determinants of PARP Inhibitor Sensitivity in Ovarian Cancer

    Science.gov (United States)

    2016-10-01

    cisplatin sensitivity (Fig. 3A). MDA-MB-436 cells harbor a BRCA15396+1G>A mutation resulting in protein misfolding , undetectable BRCA1 and RAD51...the DNA damage response; and 3) To identify small molecules that kill N-terminal deficient BRCA1 protein expressing cells. Procuring Contracting...hypothesized that a range of common ovarian cancer predisposing germ-line BRCA1 gene mutations produce semi-functional proteins that are capable of

  15. Simultaneous determination of metallic impurities in ThO2 using energy dispersive x-ray fluorescence technique

    International Nuclear Information System (INIS)

    Natarajan, V.; Dhawale, B.A.; Hon, N.S.; Rajeswari, B.; Godbole, S.V.

    2007-01-01

    With a view to examining the feasibility of determination of some common metallic impurities in ThO 2 matrix, energy dispersive x-ray fluorescence method was developed. A series of synthetic ThO 2 standards, containing common impurities at 100-500 ppm level, were prepared. The spectrometer conditions were optimized for simultaneous determination of these elements. Using the optimum parameters, calibration curves were set up for different analyte elements. Using the method, impurities in two synthetic samples were determined. (author)

  16. [Simultaneous determination of daphnetin, daphnoretin, daphneticin in rat plasma by LC-MS/MS and its application in pharmacokinetic study].

    Science.gov (United States)

    Hu, Yi-Yi-Li-Ge-Qi; Cao, Sa-Li; Lin, Long-Fei; Fu, Jing; Dong, Xiao-Xu; Yang, Chun-Jing; Zhang, Miao; Ni, Jian

    2017-05-01

    To establish HPLC-MS/MS method for simultaneous determination of daphnetin, daphnoretin, and daphneticin in rat plasma after oral and intravenous administration of Daphne giraldii extract, and then use them in the calculation of pharmacokinetic parameters. Six sprague-dawley rats received intragastric administration of D. giraldii extract (daphnetin, daphnoretin and daphneticin were 88.40, 3.24 and 4.28 mg•kg⁻¹, respectively). Their drug plasma concentration was determined by LC-MS/MS with schisandrin as an internal standard to draw plasma concentration-time curve. The pharmacokinetic parameters were calculated by Kinetica 4.4. The results showed that the linear range was 5-1 000 μg•L⁻¹ for daphnetin, daphnoretin and daphneticin, and the method ological test showed conformance to the requirements.The intraday and inter-day variable coefficients (RSD) were both less than 15.0%, indicating that both of legitimate precise and accuracy were consistent with the analysis requirements of biological samples. For daphnetin, the pharmacokinetic parameters Tmax, Cmax, AUC0-t, T1/2 and MRT were 4 h, 858.96 μg•L⁻¹, 10 566.4 μg•L⁻¹•h, 5.19 h and 9.43 h, respectively. For daphnoretin, the pharmacokinetic parameters Tmax, Cmax, AUC0-t, T1/2 and MRT were 2.92 h, 178.00 μg•L⁻¹, 905.89 μg•L⁻¹•h, 3.50 h and 6.95 h, respectively. For daphneticin, the pharmacokinetic parameters Tmax, Cmax, AUC0-t, T1/2 and MRT were 2 h, 36.67 μg•L⁻¹, 355.11 μg•L⁻¹•h, 4.95 h and 8.27 h, respectively. The LC-MS/MS analysis method established in this study was proved to be so accurate and sensitive that it can be applied to the pharmacokinetic study of daphnetin, daphnoretin and daphneticin. Copyright© by the Chinese Pharmaceutical Association.

  17. Simultaneous determination of benznidazole and itraconazole using spectrophotometry applied to the analysis of mixture: A tool for quality control in the development of formulations

    Science.gov (United States)

    Pinho, Ludmila A. G.; Sá-Barreto, Lívia C. L.; Infante, Carlos M. C.; Cunha-Filho, Marcílio S. S.

    2016-04-01

    The aim of this work was the development of an analytical procedure using spectrophotometry for simultaneous determination of benznidazole (BNZ) and itraconazole (ITZ) in a medicine used for the treatment of Chagas disease. In order to achieve this goal, the analysis of mixtures was performed applying the Lambert-Beer law through the absorbances of BNZ and ITZ in the wavelengths 259 and 321 nm, respectively. Diverse tests were carried out for development and validation of the method, which proved to be selective, robust, linear, and precise. The lower limits of detection and quantification demonstrate its sensitivity to quantify small amounts of analytes, enabling its application for various analytical purposes, such as dissolution test and routine assays. In short, the quantification of BNZ and ITZ by analysis of mixtures had shown to be efficient and cost-effective alternative for determination of these drugs in a pharmaceutical dosage form.

  18. Simultaneous determination of benznidazole and itraconazole using spectrophotometry applied to the analysis of mixture: A tool for quality control in the development of formulations.

    Science.gov (United States)

    Pinho, Ludmila A G; Sá-Barreto, Lívia C L; Infante, Carlos M C; Cunha-Filho, Marcílio S S

    2016-04-15

    The aim of this work was the development of an analytical procedure using spectrophotometry for simultaneous determination of benznidazole (BNZ) and itraconazole (ITZ) in a medicine used for the treatment of Chagas disease. In order to achieve this goal, the analysis of mixtures was performed applying the Lambert-Beer law through the absorbances of BNZ and ITZ in the wavelengths 259 and 321 nm, respectively. Diverse tests were carried out for development and validation of the method, which proved to be selective, robust, linear, and precise. The lower limits of detection and quantification demonstrate its sensitivity to quantify small amounts of analytes, enabling its application for various analytical purposes, such as dissolution test and routine assays. In short, the quantification of BNZ and ITZ by analysis of mixtures had shown to be efficient and cost-effective alternative for determination of these drugs in a pharmaceutical dosage form. Copyright © 2016. Published by Elsevier B.V.

  19. Electrochemical fabrication of a novel ZnO/cysteic acid nanocomposite modified electrode and its application to simultaneous determination of sunset yellow and tartrazine.

    Science.gov (United States)

    Dorraji, Parisa S; Jalali, Fahimeh

    2017-07-15

    A new nanocomposite (ZnO/Cysteic acid) was deposited on glassy carbon electrode by cyclic voltammetry. Uniform deposition of the nanocomposite was observed by scanning electron microscopy. The electron transfer characteristics of two food additives, sunset yellow and tartrazine, were greatly improved on the modified electrode. The prepared electrode was used in the sensitive simultaneous determination of sunset yellow and tartrazine by differential pulse voltammetry. Linear calibration curves were obtained in the concentration ranges of 0.1-3.0, and 0.07-1.86μM, and detection limits of 0.03 and 0.01μM for sunset yellow and tartrazine, respectively. The proposed method was evaluated by determination of the dyes in processed soft drinks with satisfactory results (recovery>95% and RSD%<5%). Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Development and Validation of a Simultaneous RP-HPLCUV/DAD Method for Determination of Polyphenols in Gels Containing S. terebinthifolius Raddi (Anacardiaceae)

    Science.gov (United States)

    Carvalho, Melina G.; Aragão, Cícero F. S; Raffin, Fernanda N.; de L. Moura, Túlio F. A.

    2017-01-01

    Topical gels containing extracts of Schinus terebinthifolius have been used to treat bacterial vaginosis. It has been reported that this species has antimicrobial, anti-inflammatory and anti-ulcerogenic properties, which can be attributed to the presence of phenolic compounds. In this work, a sensitive and selective reversed-phase HPLC-UV/DAD method for the simultaneous assay of six polyphenols that could be present in S. terebinthifolius was developed. The method was shown to be accurate and precise. Peak purity and similarity index both exceeded 0.99. Calibration curves were linear over the concentration range studied, with correlation coefficients between 0.9931 and 0.9974. This method was used to determine the polyphenol content of a hydroalcoholic extract and pharmacy-compounded vaginal gel. Although the method is useful to assess the 6 phenolic compounds, some compounds could not be detected in the products. SUMMARY A sensitive, selective, accurate and precise reversed-phase HPLC-UV/DAD method for the simultaneous assay of six polyphenols in S. terebinthifolius Raddi Abbreviations used: RP-HPLC-UV/DAD: Reverse Phase High Performance Liquid Chromatograph with Ultraviolet and Diode Array Detector, HPLC: High Performance Liquid Chromatograph, HPLC-UV: High Performance Liquid Chromatograph with Ultraviolet Detector, ANVISA: Brazilian National Health Surveillance Agency, LOD: Limit of detection, LOQ: Limit of quantitation PMID:28539726

  1. Development and Validation of a Simultaneous RP-HPLCUV/DAD Method for Determination of Polyphenols in Gels ContainingS. terebinthifoliusRaddi (Anacardiaceae).

    Science.gov (United States)

    Carvalho, Melina G; Aragão, Cícero F S; Raffin, Fernanda N; de L Moura, Túlio F A

    2017-01-01

    Topical gels containing extracts of Schinus terebinthifolius have been used to treat bacterial vaginosis. It has been reported that this species has antimicrobial, anti-inflammatory and anti-ulcerogenic properties, which can be attributed to the presence of phenolic compounds. In this work, a sensitive and selective reversed-phase HPLC-UV/DAD method for the simultaneous assay of six polyphenols that could be present in S. terebinthifolius was developed. The method was shown to be accurate and precise. Peak purity and similarity index both exceeded 0.99. Calibration curves were linear over the concentration range studied, with correlation coefficients between 0.9931 and 0.9974. This method was used to determine the polyphenol content of a hydroalcoholic extract and pharmacy-compounded vaginal gel. Although the method is useful to assess the 6 phenolic compounds, some compounds could not be detected in the products. A sensitive, selective, accurate and precise reversed-phase HPLC-UV/DAD method for the simultaneous assay of six polyphenols in S. terebinthifolius Raddi Abbreviations used: RP-HPLC-UV/DAD: Reverse Phase High Performance Liquid Chromatograph with Ultraviolet and Diode Array Detector, HPLC: High Performance Liquid Chromatograph, HPLC-UV: High Performance Liquid Chromatograph with Ultraviolet Detector, ANVISA: Brazilian National Health Surveillance Agency, LOD: Limit of detection, LOQ: Limit of quantitation.

  2. First report on hemoglobin electrostatic immobilization on WO3 nanoparticles: application in the simultaneous determination of levodopa, uric acid, and folic acid.

    Science.gov (United States)

    Ghodsi, Javad; Rafati, Amir Abbas; Shoja, Yalda

    2016-05-01

    This work describes the first report about the simultaneous determination of levodopa (L-DOPA) with folic acid (FA) and uric acid (UA) based on electrocatalytic oxidation of L-DOPA with peroxidase properties of hemoglobin (Hb) in the presence of H2O2 as Hb activator. Bovine Hb was electrostatically immobilized on WO3 nanoparticles (WO3NPs) in pH between Hb and WO3NP isoelectric points, and subsequently, a carbon paste electrode (CPE) was modified with the obtained WO3NPs-Hb and multiwalled carbon nanotubes (MWCNTs). The resulting biosensor supplied a sensitive and suitably stable biosensor for the simultaneous determination of L-DOPA, UA, and FA. The obtained linear range and detection limit for L-DOPA, UA, and FA were completely acceptable, and the biosensor response time for these molecules was relatively short so that it reaches about 95 % of its maximum response in less than 10 s. The applicability of the current biosensor was confirmed with the determination of L-DOPA in the presence of fixed amounts of FA and UA in some real samples by the standard addition method.

  3. Simultaneous determination of fifteen illegal dyes in animal feeds and poultry products by ultra-high performance liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    Liu, Rongyuan; Hei, Wenjing; He, Pingli; Li, Zhen

    2011-08-15

    With the increasing presence of illegal dyes, such as sudan reds and malachite green, in animal feeds and food products during the last few years, there is an urgent need of accurate quantitative determination methods for these illicit compounds. Here we established an accurate method for the simultaneous determination of 15 illegal dyes in animal feeds, meat, eggs and other food products using ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS). The samples were extracted with a simple procedure using acetonitrile and solid phase extraction cleaning up. The application of C(18) rapid column can achieve satisfactory separation of the 15 dyes within 16 min; and multiple reaction monitoring of positive ions ensure confirmative detection of these illegal dyes. With the developed method, a sample can be analyzed in less than 2h. Dyes spiked in feeds, poultry meat and eggs in the range of 0.1-5.0 mg kg(-1) were tested in terms of linearity, sensitivity, repeatability and recovery. Recoveries for the compounds ranged from 60 to 140%. Intra- and inter-day precisions (RSDs) were less than 15%. Limit of quantification ranged from 0.01 to 5.61 μg kg(-1) for different dyes. The developed UHPLC-MS/MS method could be used as a qualitative and quantitative technique for the simultaneous determination of illegal dyes in animal feeds and poultry products. Copyright © 2011 Elsevier B.V. All rights reserved.

  4. One-shot flow injection spectrophotometric simultaneous determination of copper, iron and zinc in patients' sera with newly developed multi-compartment flow cell

    International Nuclear Information System (INIS)

    Teshima, Norio; Gotoh, Shingo; Ida, Kazunori; Sakai, Tadao

    2006-01-01

    We propose here an affordable flow injection method for simultaneous spectrophotometric determination of copper, iron and zinc in patients' sera. The use of a newly designed multi-compartment flow cell allowed the simultaneous determination of the three metals with a single injection ('one-shot') and a double beam spectrophotometer. The chemistry relied on the reactions of these metals with 2-(5-nitro-2-pyridylazo)-5-[N-propyl-N-(3-sulfopropyl)amino]phenol (nitro-PAPS) to form corresponding colored complexes. At pH 3.8, only copper-nitro-PAPS complex was formed in the presence of pyrophosphate as a masking agent for iron, and then the copper and iron(II) complexes were formed in the presence of reductant (ascorbic acid) at the same pH, and finally all three metals reacted with nitro-PAPS at pH 8.6. The characteristics were introduced into the flow system to determine each metal selectively and sensitively. Under the optimum conditions, linear calibration curves for the three metals were obtained in the range of 0.01-1 mg L -1 with a sample throughput rate of 20 h -1 . The limits of detection (3σ) were 3.9 μg L -1 for copper, 4.1 μg L -1 for iron and 4.0 μg L -1 for zinc. The proposed method was applied to analysis of some patients' sera

  5. One-step electrochemical approach for the preparation of graphene wrapped-phosphotungstic acid hybrid and its application for simultaneous determination of sunset yellow and tartrazine

    International Nuclear Information System (INIS)

    Gan Tian; Sun Junyong; Cao Shuqin; Gao Fuxing; Zhang Yuxia; Yang Yingqin

    2012-01-01

    Highlights: ► Graphene layer–wrapped PTA hybrid is one–step electropolymerized onto GCE surface. ► Graphene–PTA/GCE is used for simultaneous detection of sunset yellow and tartrazine. ► The oxidation mechanisms of sunset yellow and tartrazine were studied. ► Sunset yellow and tartrazine contents in soft drink samples are successfully determined. - Abstract: We have demonstrated a one-step and effective electrochemical method to prepare graphene (GN) layer-wrapped phosphotungstic acid (PTA) hybrid on the surface of glassy carbon electrode (GCE) using graphene as an electron transfer mediator. The PTA coupled with graphene provides good selectivity and high sensitivity for the simultaneous determination of two synthetic food colorants, sunset yellow and tartrazine, exhibiting as well-defined oxidation peaks in differential pulse voltammetry with a peak potential separation of ca. 260 mV. The detection limit was found to be 0.5 μg L −1 for sunset yellow and 30.0 μg L −1 for tartrazine. The interference of some common food additives was studied and it was concluded that application of this method for the determination of sunset yellow and tartrazine in several commercial soft drink samples led to satisfactory results. This study provides useful further evidences for the development of portable sensors for food additives.

  6. Reliability of direct sensitivity determination of blood cultures

    International Nuclear Information System (INIS)

    Noman, F.; Ahmed, A.

    2008-01-01

    The aim of this study was to evaluate the error in interpreting antimicrobial sensitivity by direct method when compared to standard method and find out if specific antibiotic-organism combination had more discrepancies. All blood culture samples received at Microbiology Laboratory from 1st July 2006 to 31st August 2006 were ncluded in the study. All samples were inoculated in automated blood culture system BACTEC 9240 which contained enriched Soybean-Casein Digest broth with CO/sub 2/. Once positive, bottles were removed from system; gram staining of the positive broths was done. Susceptibility test was performed from positive broth, on MHA (Mueller-Hinton Agar), with antibiotics panel according to gram stain result. All positive broths were also sub-cultured on blood agar, chocolate agar and McConkey agar for only gram-negative rods. Next day, the zone sizes of all antibiotics were recorded using measuring scale and at the same time susceptibility test was repeated from isolated colonies from subcultures, with inoculums prepared of McFarland 0.5 standard 0.2 Staphylococcus aureus (ATCC 29213); E.coli (ATCC 25922) and Pseudomonas aeruginosa (ATCC 27853) were included as quality control strain. Zone sizes were interpreted as sensitive (S), resistant (R) and intermediate (I) according to CLSI recommendation. Two results were compared and recorded. Out of a total 1083 combinations, zone diameters by standard method were either equal or greater than direct zone diameter (never smaller). Most of the discrepancies were in b-lactam/b-lactamase combinations and aminoglycosides. While reporting these groups of antibiotics with direct sensitivity test, one should be cautious. These are the major antibiotic used for life-threatening infections. In case of being heavy/lighter standard inoculums or marginal zones, repeating with standard method should be preferred to minimize the chances of error. (author)

  7. Fourth-order derivative spectrophotometric method for simultaneous determination of pseudoephedrine and naproxen in pharmaceutical dosage forms

    Science.gov (United States)

    Souri, Effat; Mosafer, Amir; Tehrani, Maliheh Barazandeh

    2016-01-01

    Combination dosage forms of naproxen sodium and pseudoephedrine hydrochloride are used for symptomatic treatment of cold and sinus disorders. In this study, fourth-order derivative spectrophotometric method was used for simultaneous determination of naproxen sodium and pseudoephedrine hydrochloride. The method was linear over the range of 2-28 μg/ml for pseudoephedrine hydrochloride and 4-200 μg/ml for naproxen sodium. The within-day and between-day coefficient of variation values were less than 5.8% and 2.5% for pseudoephedrine hydrochloride and naproxen sodium, respectively. The application of the proposed method for simultaneous determination of naproxen and pseudoephedrine in dosage forms was demonstrated without any special pretreatment. PMID:27168748

  8. Simultaneous determination of cadmium, lead and mercury ions at trace level by magnetic solid phase extraction with Fe@Ag@Dimercaptobenzene coupled to high performance liquid chromatography.

    Science.gov (United States)

    Zhou, Qingxiang; Lei, Man; Liu, Yongli; Wu, Yalin; Yuan, Yongyong

    2017-12-01

    Pollution resulted from heavy metal ions have absorbed much attention, and it is of great importance to develop sensitive and simultaneous determination method for them with common technologies without highly sensitive instruments. We prepared a new and functional core-shell magnetic nano-material, Fe@Ag@dimercaptobenzene (Fe@Ag@DMB), by a one-step method with sodium borohydride as the reducing agent and transmission electron microscopy (TEM) and energy dispersive spectrometer (EDS) were used for characterisation. The mercapto functional groups on the newly synthesised magnetic nanoparticles could interact with Cd 2+ , Pb 2+ , and Hg 2+ ions in water samples and then efficient extraction for Cd 2+ , Pb 2+ , and Hg 2+ ions was achieved. DDTC-Na solution was a good elutent for elution of these ions from Fe@Ag@DMB nanoparticles. Based on these, a sensitive method was developed for simultaneous preconcentration and determination of the aforementioned ions using magnetic Fe@Ag@DMB nanoparticles as the magnetic solid phase extraction adsorbent prior to high performance liquid chromatography coupled with variable wavelength detection. Under the optimal conditions, the detection limits of the three metal ions were in the range of 0.011-0.031μgL -1 , and precisions were below 2.37% (n=6). The proposed method was evaluated with real water samples, and excellent spiked recoveries achieved indicated that the developed method would be a promising tool for monitoring these heavy metal ions in water samples. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Simultaneous determination of macronutrients, micronutrients and trace elements in mineral fertilizers by inductively coupled plasma optical emission spectrometry

    Science.gov (United States)

    de Oliveira Souza, Sidnei; da Costa, Silvânio Silvério Lopes; Santos, Dayane Melo; dos Santos Pinto, Jéssica; Garcia, Carlos Alexandre Borges; Alves, José do Patrocínio Hora; Araujo, Rennan Geovanny Oliveira

    2014-06-01

    An analytical method for simultaneous determination of macronutrients (Ca, Mg, Na and P), micronutrients (Cu, Fe, Mn and Zn) and trace elements (Al, As, Cd, Pb and V) in mineral fertilizers was optimized. Two-level full factorial design was applied to evaluate the optimal proportions of reagents used in the sample digestion on hot plate. A Doehlert design for two variables was used to evaluate the operating conditions of the inductively coupled plasma optical emission spectrometer in order to accomplish the simultaneous determination of the analyte concentrations. The limits of quantification (LOQs) ranged from 2.0 mg kg- 1 for Mn to 77.3 mg kg- 1 for P. The accuracy and precision of the proposed method were evaluated by analysis of standard reference materials (SRMs) of Western phosphate rock (NIST 694), Florida phosphate rock (NIST 120C) and Trace elements in multi-nutrient fertilizer (NIST 695), considered to be adequate for simultaneous determination. Twenty-one samples of mineral fertilizers collected in Sergipe State, Brazil, were analyzed. For all samples, the As, Ca, Cd and Pb concentrations were below the LOQ values of the analytical method. For As, Cd and Pb the obtained LOQ values were below the maximum limit allowed by the Brazilian Ministry of Agriculture, Livestock and Food Supply (Ministério da Agricultura, Pecuária e Abastecimento - MAPA). The optimized method presented good accuracy and was effectively applied to quantitative simultaneous determination of the analytes in mineral fertilizers by inductively coupled plasma optical emission spectrometry (ICP OES).

  10. Simultaneous spectrophotometric determination of binary mixtures of nickel, cobalt and vanadium with 3-(picolydene)benzenesulphonic acid 2-hydroxylhydrazone

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Vargas, M.; Milla, M.; Antequera, I.; Perez-Bustamante, J.A.

    1985-05-01

    The synthesis and characterization of a water-soluble reagent, 3-(picolydene)benzenesulphonic acid 2-hydroxybenzoylhydrazone, is described. The reagent is stable in aqueous media. The colour reactions with nickel(II), cobalt(II) and vanadium(V) ions in slightly acidic solutions have molar absorptivities in the range 1.4-3.6 x 10U l mol cm . Simultaneous determinations of Ni, Co and V in binary mixtures are possible. Interference data are reported.

  11. Body fat, sweetness sensitivity, and preference: determining the relationship.

    Science.gov (United States)

    Ettinger, Laurel; Duizer, Lisa; Caldwell, Tristaca

    2012-01-01

    The study was conducted to evaluate whether body fat is a better measure than body mass index (BMI) for determining the relationship between body size and sweetness perception and preference. Seventy-two women were recruited and separated into two groups. First, BMI was determined and used to classify each woman as either normal weight (18.5 to 24.9 kg/m²) or overweight (>25.0 kg/m²). Body fat was determined from skinfold sites and used to categorize women into normal (sweetness were evaluated to determine the women's liking for sweetness, and the perceived sweetness of the sample. Women in the overweight BMI and body fat groups had higher sucrose threshold values than did women in the normal groups. When presented with custards of varying sucrose levels, the overweight BMI and body fat groups had a significantly increased liking for sweetness as sucrose concentration increased. Body fat measures were as effective as BMI measures in determining sweetness preference. Future research should be conducted to determine whether body fat and measures, such as waist circumference, can be predictive tools for sweetness preference.

  12. A sensitive electrochemical sensor using an iron oxide/graphene composite for the simultaneous detection of heavy metal ions.

    Science.gov (United States)

    Lee, Sohee; Oh, Jiseop; Kim, Dongwon; Piao, Yuanzhe

    2016-11-01

    We report an analytical assessment of an iron oxide (Fe2O3)/graphene (G) nanocomposite electrode used in combination with in situ plated bismuth (Bi) working as an electrochemical sensor for the determination of trace Zn(2+), Cd(2+), and Pb(2+). The as-synthesized nanocomposites were characterized by transmission electron microscopy, scanning electron microscopy, thermo-gravimetric analyzer, and X-ray diffraction. The electrochemical properties of the Fe2O3/G/Bi composite modified electrode were investigated. Differential pulse anodic stripping voltammetry was applied for the detection of metal ions. Due to the synergetic effect between graphene and the Fe2O3 nanoparticles, the modified electrode showed improved electrochemical catalytic activity high sensitivity toward trace heavy metal ions. Several parameters such as the preconcentration potential, bismuth concentration, preconcentration time, and pH were carefully optimized to determine the target metal ions. Under optimized conditions, the linear range of the electrode was 1-100μgL(-1) for Zn(2+), Cd(2+), and Pb(2+), and the detection limits were 0.11μgL(-1), 0.08μgL(-1), and 0.07μgL(-1), respectively (S/N =3). Repeatability (% RSD) was found to be 1.68% for Zn(2+), 0.92% for Cd(2+), and 1.69% for Pb(2+) for single sensor with 10 measurements and 0.89% for Zn(2+), 1.15% for Cd(2+), and 0.91% for Pb(2+) for 5 different electrodes. The Fe2O3/G/Bi composite electrode was successfully applied to the analysis of trace metal ions in real samples. The solventless thermal decomposition method applied to the simple and easy synthesis of nanocomposite electrode materials can be extended to the synthesis of nanocomposites and promising electrode materials for the determination of heavy metal ions. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Compositional Determination of Shale with Simultaneous Neutron and X-ray Tomography

    Science.gov (United States)

    LaManna, J.; Hussey, D. S.; Baltic, E.; Jacobson, D. L.

    2017-12-01

    Understanding the distribution of organic material, mineral inclusions, and porosity are critical to properly model the flow of fluids through rock formations in applications ranging from hydraulic fracturing and gas extraction, CO2 sequestration, geothermal power, and aquifer management. Typically, this information is obtained on the pore scale using destructive techniques such as focused ion beam scanning electron microscopy. Neutrons and X-rays provide non-destructive, complementary probes to gain three-dimensional distributions of porosity, minerals, and organic content along with fluid interactions in fractures and pore networks on the core scale. By capturing both neutron and X-ray tomography simultaneously it is possible to capture slowly dynamic or stochastic processes with both imaging modes. To facilitate this, NIST offers a system for simultaneous neutron and X-ray tomography at the Center for Neutron Research. This instrument provides neutron and X-ray beams capable of penetrating through pressure vessels to image the specimen inside at relevant geological conditions at resolutions ranging from 15 micrometers to 100 micrometers. This talk will discuss current efforts at identifying mineral and organic content and fracture and wettability in shales relevant to gas extraction.

  14. Simultaneous determination of the repertoire of classical neurotransmitters released from embryonal carcinoma stem cells using online microdialysis coupled with hydrophilic interaction chromatography–tandem mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Ya-Bin [Department of Pharmacology and Chemical Biology, Shanghai Jiao Tong University School of Medicine, 280 South Chongqing Road, Shanghai 200025 (China); Collaborative Innovation Center for Translational Medicine, Shanghai Jiao Tong University School of Medicine, 280 South Chongqing Road, Shanghai 200025 (China); Sun, Fan [Department of Pharmacology and Chemical Biology, Shanghai Jiao Tong University School of Medicine, 280 South Chongqing Road, Shanghai 200025 (China); Teng, Lin [Department of Pharmacology and Chemical Biology, Shanghai Jiao Tong University School of Medicine, 280 South Chongqing Road, Shanghai 200025 (China); Department of Cardiology and Institute of Cardiovascular Diseases, The First College of Clinical Medical Sciences, China Three Gorges University, Yichang 443000, Hubei (China); Li, Wen-Bin; An, Shi-Min [Department of Pharmacology and Chemical Biology, Shanghai Jiao Tong University School of Medicine, 280 South Chongqing Road, Shanghai 200025 (China); Collaborative Innovation Center for Translational Medicine, Shanghai Jiao Tong University School of Medicine, 280 South Chongqing Road, Shanghai 200025 (China); Zhang, Chun; Yang, Xin-Jie; Lv, Hao-Yu; Ding, Xu-Ping [Department of Pharmacology and Chemical Biology, Shanghai Jiao Tong University School of Medicine, 280 South Chongqing Road, Shanghai 200025 (China); Zhu, Liang, E-mail: zhuliang17@gmail.com [Department of Pharmacology and Chemical Biology, Shanghai Jiao Tong University School of Medicine, 280 South Chongqing Road, Shanghai 200025 (China); Collaborative Innovation Center for Translational Medicine, Shanghai Jiao Tong University School of Medicine, 280 South Chongqing Road, Shanghai 200025 (China); and others

    2014-11-07

    Highlights: • An online MD-HILIC–MS/MS method for simultaneously measuring the repertoire of classical transmitters was developed and validated. • Hydrophilic interaction chromatography (HILIC) was successfully employed to online system. • Stable isotope labeled internal standards and authentic matrix have been applied to guarantee reliable results. • The method features simple procedure (no sample preparation), high recovery (≥73%), high accuracy (89.36% ≤ RE ≤ 116.89%), good reproducibility (2.18% ≤ RSD ≤ 14.56%), and sensitive limits of detection (2 pg for acetylcholine, serotonin, and glutamate, 10 pg for dopamine, norepinephrine, GABA, and glycine). - Abstract: Dynamic, continuous, and simultaneous multi-analysis of transmitters is important for the delineation of the complex interactions between the neuronal and intercellular communications. But the analysis of the whole repertoire of classical transmitters of diverse structure is challenging due to their different physico-chemical properties and to their high polarity feature which leads to poor retention in traditional reversed-phase columns during LC–MS analysis. Here, an online microdialysis coupled with hydrophilic interaction chromatography–tandem mass spectrometry (online MD-HILIC–MS/MS) detection method was developed for the simultaneous measurement of the repertoire of classical transmitters (acetylcholine, serotonin, dopamine, norepinephrine, glutamate, GABA, and glycine). Stable isotope labeled internal standards and authentic matrix have been applied to guarantee reliable results. The method was successfully employed to reveal the characteristics of transmitter release from embryonal carcinoma stem cells. The method features simple procedure (no sample preparation), high recovery (≥73%), high accuracy (89.36% ≤ RE ≤ 116.89%), good reproducibility (2.18% ≤ RSD ≤ 14.56%), and sensitive limits of detection (2 pg for acetylcholine, serotonin, and glutamate, 10 pg

  15. Sensitive metal ions (II) determination with resonance Raman method

    Science.gov (United States)

    Yu, Zhi; Bracero, Lucas A.; Chen, Lei; Song, Wei; Wang, Xu; Zhao, Bing

    2013-03-01

    In this paper, a new proposal for the quantitative evaluation of divalent metal ions (M2+) is developed by the use of the competitive resonance Raman (RR)-based method. Upon excitation with light of the appropriate wavelength (532 nm), a strong electric field is generated that couples with the resonance of the complex (zincon-M2+), increasing the character signals of these complexes, resulting in sensitive detection. Herein, the RR probe, zincon-M2+ complex that the RR intensity gets lower with the decreasing of the M2+ concentration, which leads to the transformation of the Raman information. As a result, by using the proposed RR-based method, we could find the liner calibration curves of Cu2+ and Ni2+, which show the potential in quantitative evaluation of an unknown sample. In addition, the abundant fingerprint information shows that RR leads to the successful analysis of a blended solution, which contains two ions: Cu2+ and Ni2+.

  16. Factors determining the sensitivity of multi-layer neutron detector

    International Nuclear Information System (INIS)

    Dedenko, G.L.; Kadilin, V.V.; Kolesnikov, S.V.; Novikov, D.V.; Samosadnyj, A.V.; Samosadnyj, V.T.

    2005-01-01

    The design of the new multi-layer neutron detector MDN2 intended for estimation of the energy spectrum of neutron flux in the 0-20 MeV energy range is described. The detector consists of five layers. Each detection layer comprises a row of helium counters and a polyethylene moderator. The data acquisition system based on the controller PRC3-6 is developed specially for the neutron detector MDN2. The influence of the number of helium-3 counters in the assembly, the moderator thickness, neutron energy and gas pressure in counters on the sensitivity of the neutron detector MDN2 is investigated by means of the program NEDSUM-2 [ru

  17. Determining sensitive stages for learning to detect predators in ...

    Indian Academy of Sciences (India)

    2014-07-10

    Jul 10, 2014 ... We conducted a series of experiments to determine if the larval S. temporalis rely solely on innate predator ... sponses in many aquatic prey animals (Kats and Dill 1998; .... Table 1. Depicts the details of experiments, different treatment groups and the chemical cues used for testing the antipredator activity of.

  18. Sensitive amperometric determination of hydrazine using a carbon ...

    Indian Academy of Sciences (India)

    Also, the sensor was used to determine hydrazine concentration in water samples with satisfactory results. Keywords. Zeolite L nanoparticles ... to enhance the electron transfer rate and overcome the high overpotential problem is the ..... able relative standard deviation (RSD) of 3.3% was calcu- lated. Five electrodes were ...

  19. Sensitive amperometric determination of hydrazine using a carbon ...

    Indian Academy of Sciences (India)

    Silver-loaded nanozeolite-L-modified carbon paste electrode (Ag/L–CPE) was used as a novel sensing platform for enhanced electrocatalytic oxidation and determination of hydrazine. Zeolite L nanoparticles were synthesized via hydrothermal approach and then characterized using various techniques such as X-ray ...

  20. Determining sensitive stages for learning to detect predators in ...

    Indian Academy of Sciences (India)

    We studied prey–predator interactions in the larval bronzed frogs (Sylvirana temporalis), which have the innate ability to detect certain predators. We conducted a series of experiments to determine if the larval S. temporalis rely solely on innate predator detection mechanisms or can also learn to use more specific cues such ...

  1. Simultaneous determination of environmental α-radionuclides using liquid scintillation counting combined with time interval analysis (TIA) and pulse shape discrimination (PSD)

    International Nuclear Information System (INIS)

    Hashimoto, T.; Sato, K.; Yoneyama, Y.; Fukuyama, N.

    1997-01-01

    Some improvements of the detection sensitivity in pulse time interval analysis (TIA) based on selective extraction of successively α-α correlated decay events within millisecond order from random or background events, were established by the utilization of PSD, to reject β/γ-pulses from α-ones and a simple chemical procedure of radium separation, together with the use of well resolved scintillator. By applying the PSD, the contribution of β-decay events was completely eliminated in both the α-spectra and the TIA distribution curves as well as the improvement into clear energy resolution and the enhancement of detection sensitivity for the TIA. As a result, the TIA and α-spectrometric analysis of 226 Ra-extract showed the existence of 223 Ra (Ac-series) and β/α-correlated events with correlated life (due to 0.16 ms due to 214 Bi(β)-> 214 Po(α)->) along with a singly well resolved α-peak to be useful for the determination of 226 Ra (U-series). The difference of half-lives (145 and 1.78 ms) due to 216 Po and 215 Po (direct daughters of 224 Ra for Th-series and 223 Ra for Ac-series, respectively) was also proven for the possibility of the simultaneous determination of both correlated events by using the TIA/PSD combined with chemical separation and liquid scintillation counting method. Finally, the simultaneous determination of three natural decay series, which include U-, Th- and Ac-series nuclides, have been conveniently carried out for some environmental samples using the present method combined with 225 Ra yield tracer (Np-series). (author)

  2. Development of a sensitive real-time PCR for simultaneous detection and subtyping of influenza A and B viruses

    Directory of Open Access Journals (Sweden)

    Daniela Amicizia

    2005-03-01

    Full Text Available

    A new real-time PCR assay, using melting curve analysis, was developed for the rapid and reliable detection and sub-typing of influenza A and B.

    In order to evaluate it’s specificity, cell culture surnatants positive for Respiratory Syncytial Virus, Parainfluenza Viruses 1, 2 and 3, Measles Virus, Influenza A (to evaluate Influenza B primer and B (to evaluate Influenza A primer were tested and all of the results were negative.

    A series of Influenza A and B cell culture-grown viruses were diluted in virus transport medium, titrated and tested to determine the analytical sensibility which equated to 0.64, 0.026, 0.64, 0.62 PFU for A/H1N1, A/H3N2, Victoria-like and Yamagata-like B viruses, respectively. Twenty-five specimens, collected during the 2001/02 and 2002/03 seasons, which were positive for A/H1N1 (n = 7, A/H3N2 (n = 10, B Victoria-lineage (n = 5 and B Yamagata-lineage (n = 3, were tested in order to evaluate the assay’s clinical sensitivity, all of the results were positive.

    The new real-time PCR appears to be a suitable tool for virological surveillance and the diagnosis of respiratory infections.

  3. Simultaneous determination of electron beam profile and material response using self-consistent iterative method

    Science.gov (United States)

    Kandel, Yudhishthir; Denbeaux, Gregory

    2016-08-01

    We develop a novel iterative method to accurately measure electron beam shape (current density distribution) and monotonic material response as a function of position. A common method is to scan an electron beam across a knife edge along many angles to give an approximate measure of the beam profile, however such scans are not easy to obtain in all systems. The present work uses only an electron beam and multiple exposed regions of a thin film of photoresist to measure the complete beam profile for any beam shape, where the material response is characterized externally. This simplifies the setup of new experimental tools. We solve for self-consistent photoresist thickness loss response to dose and the electron beam profile simultaneously by optimizing a novel functional iteratively. We also show the successful implementation of the method in a real world data set corrupted by noise and other experimental variabilities.

  4. Chemometric simultaneous determination of Sofosbuvir and Ledipasvir in pharmaceutical dosage form

    Science.gov (United States)

    Khalili, Mahsa; Sohrabi, Mahmoud Reza; Mirzabeygi, Vahid; Torabi Ziaratgahi, Nahid

    2018-04-01

    Partial least squares (PLS), different families of continuous wavelet transform (CWT), and first derivative spectrophotometry (DS) techniques were studied for quantification of Sofosbuvir (SFB) and Ledipasvir (LDV) simultaneously without separation step. The components were dissolved in Acetonitrile and the spectral behaviors were evaluated in the range of 200 to 400 nm. The ultraviolet (UV) absorbance of LDV exhibits no interferences between 300 and 400 nm and it was decided to predict the LDV amount through the classic spectrophotometry (CS) method in this spectral region as well. Data matrix of concentrations and calibrated models were developed, and then by applying a validation set the accuracy and precision of each model were studied. Actual concentrations versus predicted concentrations plotted and good correlation coefficients by each method resulted. Pharmaceutical dosage form was quantified by developed methods and the results were compared with the High Performance Liquid Chromatography (HPLC) reference method. Analysis Of Variance (ANOVA) in 95% confidence level showed no significant differences among methods.

  5. Sensitive determination of triacetone triperoxide explosives using electrogenerated chemiluminescence.

    Science.gov (United States)

    Parajuli, Suman; Miao, Wujian

    2013-08-20

    Sensitive and selective detection and quantification of high explosive triacetone triperoxide (TATP) with electrogenerated chemiluminescence (ECL) at a glassy carbon electrode in water-acetonitrile solvent mixture were reported. In the presence of ruthenium(II) tris(bipyridine), TATP or hydrogen peroxide derived from TATP via UV irradiation or acid treatment produced ECL emissions upon cathodic potential scanning. Interference from hydrogen peroxide on TATP detection was eliminated by pretreatment of the analyte with catalase enzyme. Selective detection of TATP from hexamethylene triperoxide diamine (HMTD, another common peroxide-based explosive) was realized by comparing ECL responses obtained from the anodic and the cathodic potential scanning; TATP produced ECL upon cathodic potential scanning only, whereas HMTD produced ECL upon both cathodic and anodic potential scanning. The hydroxyl radical formed after the electrochemical reduction of TATP was believed to be the key intermediate for ECL production, and its stability was strongly dependent on the solution composition, which was verified with electron paramagnetic resonance spectroscopy. A detection limit of 2.5 μM TATP was obtained from direct electrochemical reduction of the explosive or hydrogen peroxide derived from TATP in 70/30% (v/v) water-acetonitrile solutions, which was ~400 times lower than that reported previously based on liquid chromatography separation and Fourier transform infrared detection.

  6. Simultaneous determination of total arsenic and total selenium in Chinese medicinal herbs by hydride generation atomic fluorescence spectrometry in tartaric acid medium

    International Nuclear Information System (INIS)

    Liu Zhanfeng; Sun Hanwen; Shen Shigang; Li Liqing; Shi Hongmei

    2005-01-01

    By HG-AFS, a new method was proposed for simultaneous determination of total arsenic and total selenium existed in the Chinese medicinal herbs in tartaric acid medium. The effects of analytical conditions and coexisting ions on the fluorescence signal intensity of analytes were investigated. The proposed method was provided with linear response ranges above 22 μg l -1 for As and 44 μg l -1 for Se, and the detection limits of 0.13 and 0.12 μg l -1 were obtained for As and Se respectively. The recoveries of 93.8-96.1% for As and 95.3-99.1% for Se, and the precision of 1.2-3.8% and 2.4-5.3% (R.S.D., n = 8) respectively, were obtained via simultaneous determined four samples of Chinese medicinal herbs and three certified botanic reference materials successfully. The proposed method has the advantages of simple operation, high sensitivity and high efficiency

  7. [An ultrafast liquid chromatography-tandem mass spectrometric method for simultaneous determination of common artificial synthetic pigments in cooked meat products].

    Science.gov (United States)

    Chen, Xiaohong; Li, Xiaoping; Zhao, Yonggang; Pan, Shengdong; Jin, Micong

    2015-07-01

    A method based on ultrafast liquid chromatography-tandem mass spectrometry (UFLC-MS/MS) has been developed for the simultaneous determination of seven synthetic pigments in cooked meat product. After the cooked meat products were extracted by mixed extraction agent, purified by WAX column, the UFLC separation was performed on a Shim-pack XR-ODS II column (75 mm x 2.0 mm, 2.2 µm) with a linear gradient elution program of acetonitrile and ammonium acetate (AmAc, 5 mmol/L) as the mobile phase. Electrospray ionization was applied and operated in the negative ion mode. The limits of quantitation (LOQs) for the seven synthetic pigments were in the range of 0.7-5.0 µg/kg. The calibration curves showed good linearities for the seven analytes in their detection ranges, and the correlative coefficients (r) were more than 0.999. The recoveries were between 88.2%-106.5% with the RSDs in the range of 1.2%-5.0%. The method is sensitive, reproducible, quick and adapts to the simultaneous determination of the seven synthetic pigments in cooked meat product.

  8. A new sensor based on glassy carbon electrode modified with nanocomposite for simultaneous determination of acetaminophen, ascorbic acid and uric acid

    Directory of Open Access Journals (Sweden)

    Mohammad Afrasiabi

    2016-09-01

    Full Text Available A chemically-modified electrode has been constructed based on a single walled carbon nanotube/chitosan/room temperature ionic liquid nanocomposite modified glassy carbon electrode (SWCNTs–CHIT–RTIL/GCE. It was demonstrated that this sensor could be used for simultaneous determination of acetaminophen (ACT, uric acid (URI and ascorbic acid (ASC. The measurements were carried out by application of differential pulse voltammetry (DPV, cyclic voltammetry (CV and chronoamperometry (CA methods. Electrochemical studies suggested that the RTIL and SWCNTs provided a synergistic augmentation that can increase current responses by improvement of electron transfers of these compounds on the electrode surface. The presence of the CHIT in the modified electrode can enhance the repeatability of the sensor by its antifouling effect. The modified electrode showed electrochemical responses with high sensitivity for ACT, URI and ASC determination, which makes it a suitable sensor for simultaneous sub-μmol L−1 detection of ACT, URI and ASC in aqueous solutions. The analytical performance of this sensor has been evaluated for detection of ACT, URI and ASC in human serum and urine with satisfactory results.

  9. Simultaneous determination of seven alkaloids from Rhizoma Corydalis Decumbentis in rabbit aqueous humor by LC-MS/MS: Application to ocular pharmacokinetic studies.

    Science.gov (United States)

    Mao, Zhengsheng; Wang, Xin; Liu, Yangdan; Huang, Yuting; Liu, Youping; Di, Xin

    2017-07-01

    This study aims to establish a fast and sensitive LC-MS/MS method for simultaneous determination of seven alkaloids from Rhizoma Corydalis Decumbentis in rabbit aqueous humor. Aqueous humor samples were processed by protein precipitation and then separated on a Thermo Syncronis C 18 column (50mm×2.1mm, 5μm) with a mobile phase using acetonitrile-0.05% formic acid (28:72, v/v). Detection of the analytes and the internal standard (coptisine) were performed in positive electrospray ionization with selected reaction monitoring. The method showed good linearity (r>0.9931) for all the seven alkaloids. This fully validated method was applied to the studies of aqueous humor pharmacokinetics of seven alkaloids from Rhizoma Corydalis Decumbentis and the effects of borneol on corneal penetration of these alkaloids into aqueous humor. This is the first work that presents a reliable LC-MS/MS method for simultaneous determination of seven alkaloids in rabbit aqueous humor and its application of ocular pharmacokinetics of seven alkaloids from Rhizoma Corydalis Decumbentis. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Simultaneous determination of uranium and plutonium in dissolver solution of irradiated fuel, using ID-TIMS. IRP-11

    International Nuclear Information System (INIS)

    Shah, Raju; Sasi Bhushan, K.; Govindan, R.; Alamelu, D.; Khodade, P.S.; Aggarwal, S.K.

    2007-01-01

    A simple sample preparation and simultaneous analysis method to determine uranium and plutonium from dissolver solution, employing the technique of Isotope Dilution Mass spectrometry has been demonstrated. The method used, co-elusion of Uranium and Plutonium from anion exchanger column after initial elution of major part of uranium in 1:5 HNO 3 in order to reduce the initial U/Pu ratio from 1000 to about 100-200 in the co-eluted fraction. Due to the availability of variable multi-collector system, different Faraday cups were adjusted to collect the different ion intensities corresponding to the different masses, during the simultaneous analysis of Uranium and Plutonium, loaded on Re double filament assembly. 233 U and PR grade Plutonium were used as spikes to determine Uranium and Plutonium from dissolver solution of irradiated fuel from research reactor. The possibility of getting the isotopic composition of uranium from the simultaneous analysis of co-eluted purified fraction of U and Pu from spiked aliquots is also explained. (author)

  11. Simultaneous determination of metronidazole and spiramycin I in human plasma, saliva and gingival crevicular fluid by LC-MS/MS.

    Science.gov (United States)

    Sagan, Cyriaque; Salvador, Arnaud; Dubreuil, Didier; Poulet, Pierre P; Duffaut, D; Brumpt, Ivan

    2005-06-15

    An analytical validation of a new liquid chromatographic-mass spectrometric (LC-MS/MS) method for simultaneous determination of metronidazole and spiramycin I concentrations in human plasma, saliva and gingival crevicular fluid (GCF) is presented. Ornidazole was used as an internal standard, and sample pre-treatment consisted of a liquid-liquid extraction. Chromatographic separation was achieved on a 5 microm Kromasil C18 column (150 mm x 4.6 mm i.d., particle size 5 microm), with a gradient using acetonitrile, water and formic acid at a flow rate of 0.9 ml/min. The methods were validated in terms of intra- and inter-batch precision (methods are applicable for accurate and simultaneous monitoring of the plasma, saliva and gingival crevicular fluid levels of metronidazole and spiramycin I from pharmacokinetic studies.

  12. Simultaneous determination of amino acids and carbohydrates in culture media of Clostridium thermocellum by valve-switching ion chromatography.

    Science.gov (United States)

    Fa, Yun; Yang, Haiyan; Ji, Chengshuai; Cui, He; Zhu, Xinshu; Du, Juan; Gao, Jun

    2013-10-10

    An improved method for the simultaneous determination of 20 amino acids and 7 carbohydrates using one-valve switching after injection, ion chromatography, and integrated pulsed amperometric detection is proposed. The resolution of the amino acids and carbohydrates in the cation trap column was investigated. In addition, parameters including flow liquid type, flow rate, concentration, and valve-switch timing were optimized. The method is time-saving, effective, and accurate for the simultaneous separation of amino acids and carbohydrates, with a mean correlation coefficient of >0.99 and repeatability of 0.5-4.6% for eight replicates. The method was successfully applied in the analysis of amino acids and carbohydrates in aseptic media and in extracellular culture media of three phenotypes of Clostridium thermocellum. Copyright © 2013 Elsevier B.V. All rights reserved.

  13. Simultaneous Determination of Copper, Zinc and Selenium in Chicken Liver by Differential Pulse Polarography

    OpenAIRE

    EKMEKCİ, Güler

    2003-01-01

    A differential pulse polarographic method for the determination of copper, zinc and selenium in chicken liver is described. It was possible to determine these elements in a single sample solution after acid digestion. Dried liver samples weighing about 3 g were digested using HNO3 and HClO4 acids. Britton-Robinson or acetate buffer has been found suitable as the supporting electrolyte. For the determination of selenium, the hydrogen catalytic peak was used after the addition of mol...

  14. Simultaneous determination of macronutrients, micronutrients and trace elements in mineral fertilizers by inductively coupled plasma optical emission spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira Souza, Sidnei de [Laboratório de Química Analítica Ambiental (LQA), Departamento de Química, Centro de Ciências Exatas e Tecnologia, Universidade Federal de Sergipe (UFS), 49100-000, São Cristovão, SE (Brazil); Silvério Lopes da Costa, Silvânio [Laboratório de Química Analítica Ambiental (LQA), Departamento de Química, Centro de Ciências Exatas e Tecnologia, Universidade Federal de Sergipe (UFS), 49100-000, São Cristovão, SE (Brazil); Coordenação de Química, Universidade Federal de Alagoas (UFAL), Campus Arapiraca, 57309-005, Arapiraca, AL (Brazil); Santos, Dayane Melo; Santos Pinto, Jéssica dos; Garcia, Carlos Alexandre Borges [Laboratório de Química Analítica Ambiental (LQA), Departamento de Química, Centro de Ciências Exatas e Tecnologia, Universidade Federal de Sergipe (UFS), 49100-000, São Cristovão, SE (Brazil); and others

    2014-06-01

    An analytical method for simultaneous determination of macronutrients (Ca, Mg, Na and P), micronutrients (Cu, Fe, Mn and Zn) and trace elements (Al, As, Cd, Pb and V) in mineral fertilizers was optimized. Two-level full factorial design was applied to evaluate the optimal proportions of reagents used in the sample digestion on hot plate. A Doehlert design for two variables was used to evaluate the operating conditions of the inductively coupled plasma optical emission spectrometer in order to accomplish the simultaneous determination of the analyte concentrations. The limits of quantification (LOQs) ranged from 2.0 mg kg{sup −1} for Mn to 77.3 mg kg{sup −1} for P. The accuracy and precision of the proposed method were evaluated by analysis of standard reference materials (SRMs) of Western phosphate rock (NIST 694), Florida phosphate rock (NIST 120C) and Trace elements in multi-nutrient fertilizer (NIST 695), considered to be adequate for simultaneous determination. Twenty-one samples of mineral fertilizers collected in Sergipe State, Brazil, were analyzed. For all samples, the As, Ca, Cd and Pb concentrations were below the LOQ values of the analytical method. For As, Cd and Pb the obtained LOQ values were below the maximum limit allowed by the Brazilian Ministry of Agriculture, Livestock and Food Supply (Ministério da Agricultura, Pecuária e Abastecimento — MAPA). The optimized method presented good accuracy and was effectively applied to quantitative simultaneous determination of the analytes in mineral fertilizers by inductively coupled plasma optical emission spectrometry (ICP OES). - Highlights: • Determination of inorganic constituents in mineral fertilizers was proposed. • Experimental design methodology was used to optimize analytical method. • The sample preparation procedure using diluted reagents (HNO{sub 3} and H{sub 2}O{sub 2}) was employed. • The analytical method was satisfactorily to the determination of thirteen elements. • The

  15. Simultaneous determination of extracellular volume and blood volume with the Volemetron

    NARCIS (Netherlands)

    Planque, B.A. de; Geyskes, C.G.; Dongen, R. van; Dorhout Mees, E.J.

    A new instrument, the “Volemetron”***, constructed to measure blood volume with radioactive isotopes, was adapted to determine 82Br distribution volume. Details of the technique arc given. Mean values of both RISA and 82Br distribution volume in normal men and women were determined. They were in

  16. Simultaneous determination of endogenous steroid hormones in human and animal plasma and serum by liquid or gas chromatography coupled to tandem mass spectrometry.

    Science.gov (United States)

    Abdel-Khalik, Jonas; Björklund, Erland; Hansen, Martin

    2013-06-01

    Analytical methodologies based on liquid or gas chromatography coupled to tandem mass spectrometry for the simultaneous determination of two or more endogenous steroid hormones in human and animal plasma and serum has received increased attention the last few years. Especially in the clinical setting steroid profiling is of major importance in disease diagnostics. This paper discusses recent findings in such multi-steroid hormone procedures published from 2001 to 2012. The aim was to elucidate possible relationships between chosen analytical technique and the obtained analyte sensitivity for endogenous steroid hormones. By evaluating the success, at which the currently applied techniques have been utilized, more general knowledge on the field is provided. Furthermore the evaluation provides directions in which future studies may be interesting to conduct. Copyright © 2013 Elsevier B.V. All rights reserved.

  17. Simultaneous determination of volatile and non-volatile nitrosamines in processed meat products by liquid chromatography tandem mass spectrometry using atmospheric pressure chemical ionisation and electrospray ionisation

    DEFF Research Database (Denmark)

    Herrmann, Susan Strange; Duedahl-Olesen, Lene; Granby, Kit

    2014-01-01

    A sensitive, selective and generic method has been developed for the simultaneous determination of the contents (μgkg−1 range) of both volatile nitrosamines (VNA) and non-volatile nitrosamines (NVNA) in processed meat products. The extraction procedure only requires basic laboratory equipment...... NVNAs with LODs generally between 0.2 and 1μgkg−1, though for a few analyte/matrix combinations higher LODs were obtained (3 to 18μgkg−1). The validation results show that results obtained for one meat product is not always valid for other meat products. We were not able to obtain satisfactory results......, it was only possible to ionize N-nitroso-thiazolidine-4-carboxylic acid (NTCA) and N-nitroso-2-methyl-thiazolidine-4-carboxylic acid (NMTCA) by ESI. The validated method was applied for the analysis of processed meat products and contents of N-nitrosodimethylamine (NDMA), N-nitrosopyrrolidine (NPYR), N...

  18. Development and Validation of RP-HPLC Method for the Simultaneous Determination of Rabeprazole Sodium and Itopride Hydrochloride in Solid Dosage Form

    Directory of Open Access Journals (Sweden)

    Rajesh Sharma

    2010-01-01

    Full Text Available A simple, sensitive, precise, accurate, rapid and reproducible reverse phase high performance liquid chromatographic procedure is developed for simultaneous determination of rabeprazole sodium and itopride hydrochloride in solid dosage form. The mobile phase used was a combination of acetonitrile: buffer (35:65 v/v and the pH was adjusted to 7.0 ± 0.1 by addition of triethylamine. The detection of the capsule dosage form was carried out at 266 nm and a flow rate employed was 1 mL/min. Linearity was obtained in the concentration range of 2 to 16 μg/mL of rabeprazole sodium and 5 to 55 μg/mL of itopride hydrochloride with a correlation coefficient of 0.9992 and 0.9996 respectively. The results of the analysis were validated statistically and recovery studies confirmed the accuracy of the proposed method.

  19. A METHOD OF AUTOMATIC DETERMINATION OF THE NUMBER OF THE ELECTRICAL MOTORS SIMULTANEOUSLY WORKING IN GROUP

    Directory of Open Access Journals (Sweden)

    A. V. Voloshko

    2016-11-01

    Full Text Available Purpose. Propose a method of automatic determination of the number of operating high voltage electric motors in the group of the same type based on the determination and analysis of the account data of power consumption, obtained from of electric power meters installed at the connection of motors. Results. The algorithm of the automatic determination program for the number of working in the same group of electric motors, which is based on the determination of the motor power minimum value at which it is considered on, was developed. Originality. For the first time a method of automatic determination of the number of working of the same type high-voltage motors group was proposed. Practical value. Obtained results may be used for the introduction of an automated accounting run of each motor, calculating the parameters of the equivalent induction motor or a synchronous motor.

  20. Facile and green fabrication of size-controlled AuNPs/CNFs hybrids for the highly sensitive simultaneous detection of heavy metal ions

    International Nuclear Information System (INIS)

    Zhang, Bin; Chen, JiaDong; Zhu, Han; Yang, TingTing; Zou, MeiLing; Zhang, Ming; Du, MingLiang

    2016-01-01

    Graphical abstract: Au nanoparticle grown on carbon nanofibers (AuNPs/CNFs) was synthesized and exhibit high sensitivity and a low detection limit of the simultaneous detection of Cd 2+ , Pb 2+ and Cu 2+ . - Highlights: • AuNPs/CNFs were fabricated via electrospinning and in situ thermal reduction. • AuNPs/CNFs/GCE were employed to simultaneously detect Cd 2+ , Pb 2+ and Cu 2+ . • The hybrids exhibited high sensitivity and low detection limitation. • We offer an effective method for the detection of heavy metal ions. - Abstract: A well-dispersed Au nanoparticle grown on carbon nanofibers (AuNPs/CNFs) with excellent electroanalytical activity and sensitivity towards the detection of heavy metal ions was synthesized via electrospinning technology and in situ thermal reduction. Field-emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM) images show that a large amount of AuNPs with a diameter of 5–15 nm was homogenously distributed on the surface of the nanofibers. The AuNPs/CNFs hybrids modified electrode was utilized as the working electrode for the simultaneous detection of heavy metal ions such as Cd 2+ , Pb 2+ and Cu 2+ through the square wave anodic stripping voltammetry (SWASV) method. The electrochemical results indicate that the simultaneous detection of Cd 2+ , Pb 2+ and Cu 2+ with a low concentration of 0.1 μM can be obtained. This work may provide an easy way to construct electrochemical sensors for the quick detection of trace heavy metal ions.

  1. Simultaneous and sensitive detection of six serotypes of botulinum neurotoxin using enzyme-linked immunosorbent assay-based protein antibody microarrays

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yanfeng; Lou, Jianlong; Jenko, Kathryn L.; Marks, James D.; Varnum, Susan M.

    2012-11-15

    Botulinum neurotoxins (BoNTs), produced by Clostridium botulinum, are a group of seven (A-G) immunologically distinct proteins and cause the paralytic disease botulism. These toxins are the most poisonous substances known to humans and are potential bioweapon agents. Therefore, it is necessary to develop highly sensitive assays for the detection of BoNTs in both clinical and environmental samples. In the present study, we have developed an ELISA-based protein antibody microarray for the sensitive and simultaneous detection of BoNT serotype A, B, C, D, E and F. With engineered high-affinity antibodies, the assays have sensitivities in buffer of 8 fM (1.2 pg/mL) for serotypes A and B, and 32 fM (4.9 pg/mL) for serotypes C, D, E, and F. Using clinical and environmental samples (serum and milk), the microarray is capable of detecting BoNT/A-F to the same levels as in standard buffer. Cross reactivity between assays for individual serotype was also analyzed. These simultaneous, rapid, and sensitive assays have the potential to measure botulinum toxins in a high-throughput manner in complex clinical or environmental samples.

  2. Analysis of odorous gases with simultaneous GC-MS and sensory determination

    Energy Technology Data Exchange (ETDEWEB)

    Orko, I.; Lehtomaeki, J.; Sandell, E.; Arnold, M. [VTT Chemical Technology, Espoo (Finland). Environmental Technology

    1995-12-31

    Industrial odorous off-gases can consist of hundreds of different compounds giving cause to odour annoyance in the vicinity of the odour-emitting plant. For the identification of the odorous components in the gas, traditional analytical methods are not always sufficient since the odour threshold values cannot often be found in literature. This report describes the development of a GC-MS sniffing port method for identifying odorous compounds in off-gases. In the method the sample is injected into a gas chromatograph and divided into two flows. The compounds in these sample flows are separated in two identical columns and detected simultaneously in a mass spectrometer and by sensory means. The olfactory detections are marked in the iongram and the odorous compounds are identified. Tenax TA adsorbent is generally used for collecting the odorous sample for analysis. The compounds are released from the adsorbent for analysis by thermal desorption. The report also describes a case study where the GC-MS sniffing port method was applied to a gaseous emission from a food factory. Over ten odorous compounds could be identified. (author)

  3. Array of potentiometric sensors for simultaneous determination of copper, silver, and cadmium ions in complex mixtures

    International Nuclear Information System (INIS)

    Shirmardi-Dezaki, Abbas; Shamsipur, Mojtaba; Akhond, Morteza; Sharghi, Hashem; Doroodmand, Mohammad Mahdi

    2012-01-01

    Graphical abstract: - Abstract: A programmed switching system combined with an array of potentiometric sensors consisting of seven potentiometric sensors (i.e., ion-selective or cross-selective electrodes) was connected directly to a pH/potentiometer and a computer (PC) to sequentially acquire the potential corresponding to water sample mixtures. The acquired potentials were recorded and saved on the PC and were used as input variables for an artificial neural network to simultaneously yield the concentrations of Cd 2+ , Cu 2+ , and Ag + in simple and complex mixtures. A feed-forward, back propagation network with a Levenburg–Maquart algorithm was employed to optimize the network parameters. Certain characteristics of each of the seven ion-selective electrodes, including selectivity coefficients, calibration curves, and response times, were also studied. A five-second delay time was used when recording the potentials of the electrodes using the switching system. The array system was also optimized for the selection of the ion-selective electrodes. A four-electrode array system was found to be the best choice for the prediction of Cd 2+ , Ag + and Cu 2+ ion concentration, but application of all seven ion-selective electrodes was necessary for prediction of these primary ions in samples containing a combination of zinc and nickel ions as interfering ions.

  4. [Comparison of pretreatment methods for the simultaneous determination of diclazuril and toltrazuril residues in chicken tissues].

    Science.gov (United States)

    Shi, Zuhao; Ge, Qinglian; Lu, Junxian; Liu, Xuexian; Gong, Jiansen; Zhu, Liangqiang; Qi, Kezong; Chen, Dingding; Peng, Kaisong

    2009-05-01

    The effects of four pretreatment methods (acetonitrile extraction-evaporation concentration, acetonitrile extraction-solid phase extraction (SPE), matrix solid-phase dispersion (MSPD) extraction and MSPD-SPE) for the simultaneous analysis of diclazuril and toltrazuril residues in chicken tissues were compared. The average recovery of 70% for the former three methods as achieved. In comparison with other methods, the MSPD method saved more than 60% in time and solvent. So, MSPD as the sample pretreatment method, an MSPD-high performance liquid chromatography with ultraviolet detection (MSPD-HPLC/UV) method was established for the analysis. Under the optimal chromatographic conditions, the linear range was between 50 and 1,000 microg/kg. At the added levels of 50, 500, 1,000 ng/g, the recoveries of diclazuril and toltrazuril in chicken tissues ranged from 71.13% - 84.02% with the relative standard deviations (RSD) in the range of 3.76% - 12.11%, and the RSDs of intra- and interday analyses ranged from 3.70% - 6.77%. The detection limits of diclazuril and toltrazuril were less than 10 microg/kg. The quantitative limits of diclazuril and toltrazuril were less than 20 microg/kg. The method meet the requirements of the residue analysis on accuracy and precision.

  5. Simple and sensitive high performance liquid chromatographic method for the simultaneous quantitation of the phenylalanine in human plasma

    Directory of Open Access Journals (Sweden)

    Hossein Danafar

    2015-09-01

    Full Text Available Phenylalanine (Phe is the most reliable indicator for the diagnosis of phenylketonuria (PKU. The purpose of this study is to establish a reliable and quick method for the assignment of Phe in peripheral capillary blood from newborns and children by high performance liquid chromatography with ultraviolet detection (HPLC-UV. PKU is an inborn error of metabolism characterized by the inability of the body to use Phe. A rapid and sensitive high performance liquid chromatographic (HPLC method has been developed for determination of Phe in plasma. The method uses a protein precipitation step with sulfosalicilic acid for sample preparation by separation on a Nova-pack C18 column using sodium acetate buffer and acetonitrile (94: 6 v/v adjusted to pH 6.5 with glacial acetic acid. The eluted peaks detected by a UV detector was set at wavelength of 215 nm. The method was validated in the range of Phe concentrations from 0.1 to 20 µg/ml. The limits of detection (LOD and quantitation (LOQ of the method were 0.05 and 0.1 µg/ml, respectively. The average drug recovery from plasma was 88.60 percent throughout the linear concentration range., with the average within-run and between-run accuracy values of 103.3 and 115.350, respectively. The method is quick, easy, very steady and precise for the screen, assignment, and evaluation of Phe in human plasma by HPLC, which is particularly a useful way for screening and diagnosis of PKU and monitoring of a diet therapy.

  6. Determination of fluoroquinolones, sulfonamides, and tetracyclines multiresidues simultaneously in porcine tissue by MSPD and HPLC–DAD

    Directory of Open Access Journals (Sweden)

    Hu Yu

    2012-02-01

    Full Text Available An efficient method is provided to detect simultaneously some important veterinary drugs from different classes in highly complex animal tissue matrix. This method using matrix solid-phase dispersion (MSPD and high performance liquid chromatography (HPLC with diode array detection (DAD is developed to effectively determine two fluoroquinolones (enoxacin and lomefloxacin, two sulfonamides (sulfanilamide and sulfamethoxazole and one tetracycline (tetracycline simultaneously in porcine tissues. In the process, MSPD methodology was used to treat samples, washed by n-hexane to remove lipid, eluted the analytes with acetonitrile–dichloromethane (1:1, v/v. Solvent acetonitrile and solvent acetic acid (0.1% were combined in a gradient. HPLC–DAD analysis of the tissue samples was performed within 15 min at a flow rate of 1.0 mL/min. The results showed that a recovery at 0.1, 0.5 and 1.0 μg/g fortification levels ranged from 80.6% to 99.2% with satisfactory relative standard deviations (RSDs (below 6.1%, n=3 and the limits of quantitation (LOQ ranged from 7 μg/kg to 34 μg/kg in porcine tissues. Utilization of the method in successfully simultaneous analysis of porcine tissue incurred with veterinary drug multiresidues is described. Keywords: Matrix solid-phase dispersion, High performance liquid chromatography, Fluoroquinolones, Sulfonamides, Tetracyclines, Multiresidues

  7. A mass spectrometry method for sensitive, specific and simultaneous detection of bovine blood meal, blood products and milk products in compound feed.

    Science.gov (United States)

    Lecrenier, M C; Planque, M; Dieu, M; Veys, P; Saegerman, C; Gillard, N; Baeten, V

    2018-04-15

    Feed sustainability is one of the biggest challenges for the next few years. Solutions have to be found that take feed quality and safety into account. Animal by-products are one valuable source of proteins. However, since the bovine spongiform encephalopathy (BSE) crisis, their use has been strictly regulated. The objective of this study was to propose a routine, sensitive and specific method using ultra-high performance liquid chromatography coupled to tandem mass spectrometry for the detection of blood-derived products and milk powder in feed. Contaminated aquafeeds were analysed in order to evaluate the sensitivity and specificity of the method. This new method meets both selectivity and sensitivity (0.1% (w/w)) requirements imposed by the European Commission for animal proteins detection methods. It offers an innovative and complementary solution for the simultaneously identification of authorised and unauthorised animal by-products such as processed animal proteins (PAPs). Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Multiplex Real-Time qPCR Assay for Simultaneous and Sensitive Detection of Phytoplasmas in Sesame Plants and Insect Vectors.

    Directory of Open Access Journals (Sweden)

    Cengiz Ikten

    Full Text Available Phyllody, a destructive and economically important disease worldwide caused by phytoplasma infections, is characterized by the abnormal development of floral structures into stunted leafy parts and contributes to serious losses in crop plants, including sesame (Sesamum indicum L.. Accurate identification, differentiation, and quantification of phyllody-causing phytoplasmas are essential for effective management of this plant disease and for selection of resistant sesame varieties. In this study, a diagnostic multiplex qPCR assay was developed using TaqMan® chemistry based on detection of the 16S ribosomal RNA gene of phytoplasmas and the 18S ribosomal gene of sesame. Phytoplasma and sesame specific primers and probes labeled with different fluorescent dyes were used for simultaneous amplification of 16SrII and 16SrIX phytoplasmas in a single tube. The multiplex real-time qPCR assay allowed accurate detection, differentiation, and quantification of 16SrII and 16SrIX groups in 109 sesame plant and 92 insect vector samples tested. The assay was found to have a detection sensitivity of 1.8 x 102 and 1.6 x 102 DNA copies for absolute quantification of 16SrII and 16SrIX group phytoplasmas, respectively. Relative quantification was effective and reliable for determination of phyllody phytoplasma DNA amounts normalized to sesame DNA in infected plant tissues. The development of this qPCR assay provides a method for the rapid measurement of infection loads to identify resistance levels of sesame genotypes against phyllody phytoplasma disease.

  9. Multiplex Real-Time qPCR Assay for Simultaneous and Sensitive Detection of Phytoplasmas in Sesame Plants and Insect Vectors.

    Science.gov (United States)

    Ikten, Cengiz; Ustun, Rustem; Catal, Mursel; Yol, Engin; Uzun, Bulent

    2016-01-01

    Phyllody, a destructive and economically important disease worldwide caused by phytoplasma infections, is characterized by the abnormal development of floral structures into stunted leafy parts and contributes to serious losses in crop plants, including sesame (Sesamum indicum L.). Accurate identification, differentiation, and quantification of phyllody-causing phytoplasmas are essential for effective management of this plant disease and for selection of resistant sesame varieties. In this study, a diagnostic multiplex qPCR assay was developed using TaqMan® chemistry based on detection of the 16S ribosomal RNA gene of phytoplasmas and the 18S ribosomal gene of sesame. Phytoplasma and sesame specific primers and probes labeled with different fluorescent dyes were used for simultaneous amplification of 16SrII and 16SrIX phytoplasmas in a single tube. The multiplex real-time qPCR assay allowed accurate detection, differentiation, and quantification of 16SrII and 16SrIX groups in 109 sesame plant and 92 insect vector samples tested. The assay was found to have a detection sensitivity of 1.8 x 102 and 1.6 x 102 DNA copies for absolute quantification of 16SrII and 16SrIX group phytoplasmas, respectively. Relative quantification was effective and reliable for determination of phyllody phytoplasma DNA amounts normalized to sesame DNA in infected plant tissues. The development of this qPCR assay provides a method for the rapid measurement of infection loads to identify resistance levels of sesame genotypes against phyllody phytoplasma disease.

  10. Simultaneous determination of eight metabolites of organophosphate and pyrethroid pesticides in urine.

    Science.gov (United States)

    Guo, Xin Y; Sun, Li S; Huang, Meng Y; Xu, Wei L; Wang, Ying; Wang, Na

    2017-01-02

    A simultaneous method for quantifying eight metabolites of organophosphate pesticides and pyrethroid pesticides in urine samples has been established. The analytes were extracted using liquid-liquid extraction coupled with WCX solid phase extraction (SPE) cartridges. Eight metabolites were chemically derivatized before analysis using gas chromatography-tandem mass spectrometry (GC-MS-MS). The separation was performed on a HP-5MS capillary column (30 m × 0.25 mm × 0.25 µm) with temperature programming. The detection was performed under electro-spray ionization (ESI) in multiple reaction monitoring (MRM) mode. An internal standard method was used. The extraction solvent, types of SPE cartridges and eluents were optimized by comparing the sample recoveries under different conditions. The results showed that the calibration curves of the five organophosphorus pesticides metabolites were linear in the range of 0.2-200 μg/L (r 2 ≥ 0.992) and that of the three pyrethroid pesticides metabolites were linear in the range of 0.025-250 μg/L (r 2 ≥ 0.991). The limits of detection (LODs, S/N ≥ 3) and the limits of quantification (LOQs, S/N ≥ 10) of the eight metabolites were 0.008-0.833 μg/L and 0.25-2.5 μg/L, respectively. The recoveries of the eight metabolites ranged from 54.08% to 82.49%. This efficient, stable, and cost-effective method is adequate to handle the large number of samples required for surveying the exposure level of organophosphorus and pyrethroid pesticides in the general population.

  11. Simultaneous Determination of Sulphur metabolites in Arabidopsis thaliana via LC-ESI-MS/MS and 34S-metabolic Labelling

    NARCIS (Netherlands)

    Hsieh, Chin-Lin; Yeh, Kai-Wun; De Kok, Luit J.; Pan, Ryh-Nan; Kuo, Yueh-Hsiung; Tseng, Mei-Hwei

    2012-01-01

    Introduction Sulphur-containing metabolites play an important role in metabolism and homeostasis. Determination of these metabolites is challenging owing to their low concentrations and the interference in mass spectrometry analysis. Objective To develop a sensitive and accurate method based on

  12. Simultaneous spectrophotometric determination of nitroaniline isomers after cloud point extraction by using least-squares support vector machines

    Science.gov (United States)

    Niazi, Ali; Ghasemi, Jahanbakhsh; Yazdanipour, Ateesa

    2007-11-01

    Cloud point extraction has been used for the preconcentration of m-nitroaniline, o-nitroaniline and p-nitroaniline and later simultaneous spectrophotometric determination using polyethylene glycol tert-octylphenyl ether (Triton X-100) as surfactant. The resolution of a ternary mixture of the nitroaniline isomers (after extraction by cloud point) by the application of least-squares support vector machines (LS-SVM) was performed. The chemical parameters affecting the separation phase and detection process were studied and optimized. Under the optimum experimental conditions (i.e. pH 7.0, Triton X-100 = 0.6%, equilibrium time 20 min and cloud point 75 °C), calibration graphs were linear in the range of 0.2-20.0, 0.1-15.0 and 0.1-17.0 μg ml -1 with detection limits of 0.08, 0.05 and 0.06 μg ml -1 for m-nitroaniline, o-nitroaniline and p-nitroaniline, respectively. The experimental calibration matrix was designed with 21 mixtures of these chemicals. The concentrations were varied between calibration graphs concentrations of nitroaniline isomers. The root mean square error of prediction (RMSEP) for m-nitroaniline, o-nitroaniline and p-nitroaniline were 0.0146, 0.0308 and 0.0304, respectively. This procedure allows the simultaneous determination of nitroaniline isomers in synthetic and real matrix samples good reliability of the determination was proved.

  13. A simple simultaneous flow injection method based on phosphomolybdenum chemistry for nitrate and nitrite determinations in water and fish samples.

    Science.gov (United States)

    Monser, L; Sadok, S; Greenway, G M; Shah, I; Uglow, R F

    2002-05-24

    A direct spectrophotometric flow injection method for the simultaneous determination of nitrite and nitrate has been developed. The method is based on the oxidation of a phosphomolybdenum blue complex by the addition of nitrite and the decrease in absorbance of the blue complex is monitored at 820 nm. The injected sample is split into two segments. One of the streams was directly reacted with the above reagent and detected as nitrite. The other stream was passed through a copperised cadmium reductor column where reduction of nitrate to nitrite occurs, and the sample was then mixed with the reagent and passed through the cell of the spectrophotometer to be detected as nitrite plus nitrate. The conditions for the flow injection manifold parameters were optimised by experimental design and the concentration of nitrite and nitrate was determined in the linear range from 0.05 to 1.15 mug ml(-1) nitrite and 0.06 to 1.6 mug ml(-1) nitrate with a detection limit of 0.01 mug ml(-1) for nitrite and 0.025 mug ml(-1) for nitrate. The method is suitable for the simultaneous determination of nitrite and nitrate in fish and water samples with a sampling rate of 25+/-2 sample per hour.

  14. Simultaneous determination of codeine and caffeine using single-walled carbon nanotubes modified carbon-ceramic electrode.

    Science.gov (United States)

    Habibi, Biuck; Abazari, Mehri; Pournaghi-Azar, Mohammad Hossein

    2014-02-01

    In the present paper, the simultaneous determination of codeine (CO) and caffeine (CF) is described by the use of single-walled carbon nanotubes modified carbon-ceramic electrode (SWCNT/CCE); prepared via a simple and rapid method. The results show that the SWCNT/CCE exhibits excellent electrochemical catalytic activity toward the oxidation of these compounds with respect to the bare CCE and offers two anodic peaks at 1.05 and 1.38 V vs. saturated calomel electrode for oxidation of CO and CF, respectively. Differential pulse voltammetry was used for simultaneous determination of CO and CF at micromolar concentration level. In the optimum conditions, it is found that the calibration graphs for CO and CF are linear in the concentration ranges 0.2-230 and 0.4-300 μM with detection limits of 0.11 and 0.25 μM for CO and CF, respectively. The SWCNT/CCE presents good stability, reproducibility, and repeatability and the proposed method has been successfully applied for determination of CO and CF in some pharmaceutical, drinking and biological samples with high recovery rate. Copyright © 2013 Elsevier B.V. All rights reserved.

  15. Spectrophotometric Determination of Iron(II and Cobalt(II by Direct, Derivative, and Simultaneous Methods Using 2-Hydroxy-1-Naphthaldehyde-p-Hydroxybenzoichydrazone

    Directory of Open Access Journals (Sweden)

    V. S. Anusuya Devi

    2012-01-01

    Full Text Available Optimized and validated spectrophotometric methods have been proposed for the determination of iron and cobalt individually and simultaneously. 2-hydroxy-1-naphthaldehyde-p-hydroxybenzoichydrazone (HNAHBH reacts with iron(II and cobalt(II to form reddish-brown and yellow-coloured [Fe(II-HNAHBH] and [Co(II-HNAHBH] complexes, respectively. The maximum absorbance of these complexes was found at 405 nm and 425 nm, respectively. For [Fe(II-HNAHBH], Beer’s law is obeyed over the concentration range of 0.055–1.373 μg mL−1 with a detection limit of 0.095 μg mL−1 and molar absorptivity ɛ, 5.6 × 104 L mol−1 cm−1. [Co(II-HNAHBH] complex obeys Beer’s law in 0.118–3.534 μg mL−1 range with a detection limit of 0.04 μg mL−1 and molar absorptivity, ɛ of 2.3 × 104 L mol−1 cm−1. Highly sensitive and selective first-, second- and third-order derivative methods are described for the determination of iron and cobalt. A simultaneous second-order derivative spectrophotometric method is proposed for the determination of these metals. All the proposed methods are successfully employed in the analysis of various biological, water, and alloy samples for the determination of iron and cobalt content.

  16. Spectrophotometric studies on the complexation equilibria of Ni and Pb with 2-carboxy-2-hydroxy-5'-sulfo-formazylbenzene. Simultaneous determination of trace amounts of Ni and Pb.

    Science.gov (United States)

    Hashem, Elham Y; Abu-Bakr, Mohamed S; Hussain, Sawsan M

    2004-01-01

    Spectrophotometric studies have been made to investigate the reaction of Nickel and Lead with 2-carboxy-2'-hydroxy-5'-sulfoformazyl-benzene (zincon) in 50%(v/v) ethanol-water at 25 degrees C and an ionic strength of 0.1 M NaClO4. A complete picture of the complexation equilibria in the pH range (4.2-12.0) for nickel and (1.9-11.5) for lead are presented. Simple, rapid, selective and sensitive methods for the spectro-photometric determination of nickel and lead has been developed based on the color reaction of their complexes with zincon. The methods allow the determination of 4.69 microg mL(-1) of nickel at pH = 6.3 (lambdamax = 665 nm) and 10.3 microg ml(-1) of lead at pH = 5.6 (lambdamax = 610 nm). The apparent molar absorptivities were epsilon = 1.3 x 10(4) L mol(-1) cm(-1) for nickel and epsilon = 0.6 x 10(4) L mol(-1) cm(-1) for lead. The interference of a large number of foreign ions and complexing agents has been studied. Thiosulphate, as masking agent allows the simultaneous determination of nickel and lead in the presence of high concentrations of copper. Ascorbic acid, sodium cyanide and or sodium fluoride provide the elimination of many other interferences. The methods have been applied successfully to the simultaneous determination of nickel and lead in an aluminium and non-ferrous alloy.

  17. Simultaneous Determination of Preservatives (Methyl Paraben and Propyl Paraben) in Sucralfate Suspension Using High Performance Liquid Chromatography

    OpenAIRE

    Rajesh M. Kashid; Santosh G. Singh; Shrawan Singh

    2011-01-01

    A reversed phase HPLC method that allows the separation and simultaneous determination of the preservatives methyl paraben (M.P.) and propyl paraben (P.P.) is described. The separations were effected by using an initial mobile phase of water: acetonitrile (50:50) on Inertsil C18 to elute P.P. and M.P. The detector wavelength was set at 205 nm. Under these conditions, separation of the two components was achieved in less than 10 min. Analytical characteristics of the separation such as precisi...

  18. Simultaneous determination of Nitazoxanide and Ofloxacin in pharmaceutical preparations using UV-spectrophotometric and high performance thin layer chromatography methods

    OpenAIRE

    Sharma, Smita; Sharma, Mukesh C.; Sahu, Nitendra K.

    2012-01-01

    Simple, precise, and accurate UV-Spectrophotometric and high-performance thin-layer chromatography (HPTLC) methods for the simultaneous determination of Nitazoxanide and Ofloxacin in pharmaceutical preparations have been developed and validated. The method was developed using aluminum plates pre-coated with silica gel 60 F254 HPTLC plates as a stationary phase with toluene:chloroform:carbon tetra chloride:toluene:glacial acetic acid solutions in the proportion of (10:5:3:0.5 v/v/v/v) as mobil...

  19. Simultaneous determination of chromium(III) and chromium(VI) in aqueous solutions by ion chromatography and chemiluminescence detection

    DEFF Research Database (Denmark)

    Gammelgaard, Bente; Jøns, O; Nielsen, B

    1992-01-01

    A method for the simultaneous determination of chromium(iii) and chromium(vi) in a flow system based on chemiluminescence was developed. A Dionex cation-exchange guard column was used to separate chromium(iii) from chromium(vi), and chromium(vi) was reduced by potassium sulfite, whereupon both...... species were detected by use of the luminol-hydrogen peroxide chemiluminescence system. Linear calibration for both species was established over the concentration range 1-1000 micrograms l-1. The precision at the 20 micrograms l-1 level was 3.5% for chromium(iii) and 3.3% for chromium(vi), respectively...

  20. Simultaneous determination of oxalic, citric, nitrilotriacetic and ethylenediamenetetraacetic acids by gas liquid chromatography of their methyl esters

    International Nuclear Information System (INIS)

    Eskell, C.J.; Pick, M.E.

    1980-04-01

    A procedure for simultaneous determination of ethylenediaminetetraacetic acid (EDTA), nitrilotriacetic acid (NTA), citric acid and oxalic acid by gas liquid chromatography is described. The involatile acids are first concerted to their volatile methyl ester derivatives by reaction with boron trifluoride in methanol. Transition metal ions (Fe 3+ , Cr 3+ and Ni 2+ ) which will be present in decontamination liquors from nuclear reactors, and form strong chelates with the acids, have been shown to cause no interference to the esterification reaction. The esters were separated by temperature programming on a 3.5 metre capillary column packed with 3% OV1 on Diatomite CQ and were detected by flame ionisation. (author)

  1. Simultaneous Determination of Preservatives (Methyl Paraben and Propyl Paraben in Sucralfate Suspension Using High Performance Liquid Chromatography

    Directory of Open Access Journals (Sweden)

    Rajesh M. Kashid

    2011-01-01

    Full Text Available A reversed phase HPLC method that allows the separation and simultaneous determination of the preservatives methyl paraben (M.P. and propyl paraben (P.P. is described. The separations were effected by using an initial mobile phase of water: acetonitrile (50:50 on Inertsil C18 to elute P.P. and M.P. The detector wavelength was set at 205 nm. Under these conditions, separation of the two components was achieved in less than 10 min. Analytical characteristics of the separation such as precision, specificity, linear range and reproducibility were evaluated. The developed method was applied for the determination of preservative M.P. and P.P. at concentration of 0.01 mg/mL and 0.1 mg/mL respectively. The method was successfully used for determining both compounds in sucralfate suspension.

  2. Ultra-performance liquid chromatography tandem mass spectrometry for simultaneous determination of natural steroid hormones in sea lamprey (Petromyzon marinus) plasma and tissues.

    Science.gov (United States)

    Wang, Huiyong; Bussy, Ugo; Chung-Davidson, Yu-Wen; Li, Weiming

    2016-01-15

    This study aims to provide a rapid, sensitive and precise UPLC-MS/MS method for target steroid quantitation in biological matrices. We developed and validated an UPLC-MS/MS method to simultaneously determine 16 steroids in plasma and tissue samples. Ionization sources of Electrospray Ionization (ESI) and Atmospheric Pressure Chemical Ionization (APCI) were compared in this study by testing their spectrometry performances at the same chromatographic conditions, and the ESI source was found up to five times more sensitive than the APCI. Different sample preparation techniques were investigated for an optimal extraction of steroids from the biological matrices. The developed method exhibited excellent linearity for all analytes with regression coefficients higher than 0.99 in broad concentration ranges. The limit of detection (LOD) was from 0.003 to 0.1ng/mL. The method was validated according to FDA guidance and applied to determine steroids in sea lamprey plasma and tissues (fat and testes) by the developed method. Copyright © 2015. Published by Elsevier B.V.

  3. Nasal insulin changes peripheral insulin sensitivity simultaneously with altered activity in homeostatic and reward-related human brain regions.

    Science.gov (United States)

    Heni, M; Kullmann, S; Ketterer, C; Guthoff, M; Linder, K; Wagner, R; Stingl, K T; Veit, R; Staiger, H; Häring, H-U; Preissl, H; Fritsche, A

    2012-06-01

    Impaired insulin sensitivity is a major factor leading to type 2 diabetes. Animal studies suggest that the brain is involved in the regulation of insulin sensitivity. We investigated whether insulin action in the human brain regulates peripheral insulin sensitivity and examined which brain areas are involved. Insulin and placebo were given intranasally. Plasma glucose, insulin and C-peptide were measured in 103 participants at 0, 30 and 60 min. A subgroup (n = 12) was also studied with functional MRI, and blood sampling at 0, 30 and 120 min. For each time-point, the HOMA of insulin resistance (HOMA-IR) was calculated as an inverse estimate of peripheral insulin sensitivity. Plasma insulin increased and subsequently decreased. This excursion was accompanied by slightly decreased plasma glucose, resulting in an initially increased HOMA-IR. At 1 h after insulin spray, the HOMA-IR subsequently decreased and remained lower up to 120 min. An increase in hypothalamic activity was observed, which correlated with the increased HOMA-IR at 30 min post-spray. Activity in the putamen, right insula and orbitofrontal cortex correlated with the decreased HOMA-IR at 120 min post-spray. Central insulin action in specific brain areas, including the hypothalamus, may time-dependently regulate peripheral insulin sensitivity. This introduces a potential novel mechanism for the regulation of peripheral insulin sensitivity and underlines the importance of cerebral insulin action for the whole organism.

  4. Simultaneous determination of 17 disperse dyes in textile by ultra-high performance supercritical fluid chromatography combined with tandem mass spectrometry.

    Science.gov (United States)

    Zhou, Ying; Du, Zhenxia; Zhang, Yun

    2014-09-01

    A simple, highly sensitive and fast procedure for the control of 17 allergenic and prohibited disperse dyes in textile products was optimized. The method was based on ultrasound assisted extraction of textile samples with 10 mL of methanol under controlled conditions (30 min, 70°C). The extracts were analyzed by the ultra-high performance supercritical fluid chromatography (UHPSFC) system coupled with triple quadrupole tandem mass spectrometry (MS/MS). Four stationary phases (BEH, BEH 2-ethyl-pyridine, HSS C18 SB and CSH fluorophenyl) were screened as well as analytical conditions (modifier percentage, backpressure and column temperature) were investigated to improve the separation. All 17 disperse dyes were simultaneously separated and determined by UHPSFC-MS/MS in 5 min. The dyes were monitored via the ESI(+) ionization method and quantified by 3-channel multiple reaction monitoring (MRM). The calibrations were performed and good linear relationship (R≥0.99) was observed within the concentration range of 2-50 μg mL(-1). Satisfactory recoveries (70.55-103.03%) of all the disperse dyes spiked with standards at different levels were demonstrated. This is the first report on the simultaneous analysis of disperse dyes using UHPSFC-MS/MS. Copyright © 2014 Elsevier B.V. All rights reserved.

  5. A review of analytical procedures for the simultaneous determination of medically important veterinary antibiotics in environmental water: Sample preparation, liquid chromatography, and mass spectrometry.

    Science.gov (United States)

    Kim, Chansik; Ryu, Hong-Duck; Chung, Eu Gene; Kim, Yongseok; Lee, Jae-Kwan

    2018-07-01

    Medically important (MI) antibiotics are defined by the United States Food and Drug Administration as drugs containing certain active antimicrobial ingredients that are used for the treatment of human diseases or enteric pathogens causing food-borne diseases. The presence of MI antibiotic residues in environmental water is a major concern for both aquatic ecosystems and public health, particularly because of their potential to contribute to the development of antimicrobial-resistant microorganisms. In this article, we present a review of global trends in the sales of veterinary MI antibiotics and the analytical methodologies used for the simultaneous determination of antibiotic residues in environmental water. According to recently published government reports, sales volumes have increased steadily, despite many countries having adopted strategies for reducing the consumption of antibiotics. Global attention needs to be directed urgently at establishing new management strategies for reducing the use of MI antimicrobial products in the livestock industry. The development of standardized analytical methods for the detection of multiple residues is required to monitor and understand the fate of antibiotics in the environment. Simultaneous analyses of antibiotics have mostly been conducted using high-performance liquid chromatography-tandem mass spectrometry with a solid-phase extraction (SPE) pretreatment step. Currently, on-line SPE protocols are used for the rapid and sensitive detection of antibiotics in water samples. On-line detection protocols must be established for the monitoring and screening of unknown metabolites and transformation products of antibiotics in environmental water. Copyright © 2018 Elsevier Ltd. All rights reserved.

  6. Simultaneous Determination of Volatile Constituents from Acorus tatarinowii Schott in Rat Plasma by Gas Chromatography-Mass Spectrometry with Selective Ion Monitoring and Application in Pharmacokinetic Study

    Directory of Open Access Journals (Sweden)

    Xue Meng

    2013-01-01

    Full Text Available A sensitive and specific gas chromatographic-mass spectrometry with selected ion monitoring (GC-MS/SIM method has been developed for simultaneous identification and quantification of α-asarone, β-asarone, and methyl eugenol of Acorus tatarinowii Schott in rat plasma. Chromatographic separation was performed on a Restek Rxi-5MS capillary column (30 m × 0.32 mm × 0.25 μm, using 1-naphthol as internal standard (IS. MS detection of these compounds and IS was performed at m/z 178, 208, 208, and 144. Intra- and interday precisions of all compounds of interest were less than 10%. The recoveries are situated in the range of 92.4–105.2%. Pharmacokinetics of methyl eugenol confirmed to be one-compartment open model, α-asarone and β-asarone was two-compartment open model, respectively. The method will probably be an alternative to simultaneous determination and pharmacokinetic study of volatile ingredients in Acorus tatarinowii Schott.

  7. Optimisation of an ultrasound-assisted extraction followed by RP-HPLC separation for the simultaneous determination of oleanolic acid, ursolic acid and oridonin content in Rabdosia rubescens.

    Science.gov (United States)

    Yang, Yu-Chiao; Wei, Ming-Chi; Huang, Ting-Chia

    2012-01-01

    Rabdosia rubescens is a commonly used herb in traditional Chinese medicine and contains diterpenoids, triterpenoids and various other compounds. Among these components, oridonin, oleanolic acid and ursolic acid have gained considerable interest concerning anti-cancer activities. However, there is no suitable currently available method for the simultaneous evaluation of these three bioactive compounds in R. rubescens. To develop an optimised ultrasound-assisted extraction (UAE) method and an efficient HPLC method for the simultaneous evaluation of the three bioactive compounds in R. rubescens. Various parameters that can potentially affect the UAE process were investigated and optimised. HPLC operating conditions were also optimised, and the chromatographic separation was performed on a C(18) -column with an acetonitrile-water gradient as the mobile phase. Validation of the HPLC technique developed showed that the method has good linearity, sensitivity, precision and accuracy. The combined UAE-HPLC method was applied to quantitate the amount of oridonin, oleanolic acid and ursolic acid in the plant sample and exhibited good repeatability (RSD (%) 92.4). Furthermore, the combined UAE-HPLC method was applied successfully to the extraction and determination of oridonin, oleanolic acid and ursolic acid content in samples obtained from different geographical regions, which is the first time that this comparison has been investigated. The combined UAE-HPLC process is a fast, convenient and appropriate method for the quantitative analysis of these three compounds in R. rubescens. Copyright © 2012 John Wiley & Sons, Ltd.

  8. Determinants for simultaneous binding of copper and platinum to human chaperone Atox1: hitchhiking not hijacking.

    Directory of Open Access Journals (Sweden)

    Maria E Palm-Espling

    Full Text Available Cisplatin (CisPt is an anticancer agent that has been used for decades to treat a variety of cancers. CisPt treatment causes many side effects due to interactions with proteins that detoxify the drug before reaching the DNA. One key player in CisPt resistance is the cellular copper-transport system involving the uptake protein Ctr1, the cytoplasmic chaperone Atox1 and the secretory path ATP7A/B proteins. CisPt has been shown to bind to ATP7B, resulting in vesicle sequestering of the drug. In addition, we and others showed that the apo-form of Atox1 could interact with CisPt in vitro and in vivo. Since the function of Atox1 is to transport copper (Cu ions, it is important to assess how CisPt binding depends on Cu-loading of Atox1. Surprisingly, we recently found that CisPt interacted with Cu-loaded Atox1 in vitro at a position near the Cu site such that unique spectroscopic features appeared. Here, we identify the binding site for CisPt in the Cu-loaded form of Atox1 using strategic variants and a combination of spectroscopic and chromatographic methods. We directly prove that both metals can bind simultaneously and that the unique spectroscopic signals originate from an Atox1 monomer species. Both Cys in the Cu-site (Cys12, Cys15 are needed to form the di-metal complex, but not Cys41. Removing Met10 in the conserved metal-binding motif makes the loop more floppy and, despite metal binding, there are no metal-metal electronic transitions. In silico geometry minimizations provide an energetically favorable model of a tentative ternary Cu-Pt-Atox1 complex. Finally, we demonstrate that Atox1 can deliver CisPt to the fourth metal binding domain 4 of ATP7B (WD4, indicative of a possible drug detoxification mechanism.

  9. Simultaneous determination of colorant mixtures used in cosmetics by partial least-squares multivariate calibration spectrophotometry

    OpenAIRE

    Capit??n Vallvey, Luis Ferm??n; Navas, N.; Avidad Casta??eda, Ramiro; Orbe Pay??, Ignacio de; Berzas-Nevado, J. J.

    1997-01-01

    In this work, since PLS-1 provided the most accurate predictions, it was applied in the proposed method for determining these colorants in commercial cosmetic products as colognes, facial tonics, deodorants, after shave lotions, bath gels, bath salts and shampoos. In all cases the obtained results are satisfactory.

  10. Simple, simultaneous gravimetric determination of calcite and dolomite in calcareous soils

    Science.gov (United States)

    Literature pertaining to determination of calcite and dolomite is not modern and describes slow methods that require expensive specialized apparatus. The objective of this paper was to describe a new method that requires no specialized equipment. Linear regressions and correlation coefficients for...

  11. Simultaneous determination of several phytohormones in natural coconut juice by hollow fiber-based liquid-liquid-liquid microextraction-high performance liquid chromatography.

    Science.gov (United States)

    Wu, Yunli; Hu, Bin

    2009-11-06

    A simple, selective, sensitive and inexpensive method of hollow fiber-based liquid-liquid-liquid microextraction (HF-LLLME) combined with high performance liquid chromatography (HPLC)-ultraviolet (UV) detection was developed for the determination of four acidic phytohormones (salicylic acid (SA), indole-3-acetic acid (IAA), (+/-) abscisic acid (ABA) and (+/-) jasmonic acid (JA)) in natural coconut juice. To the best of our knowledge, this is the first report on the use of liquid phase microextraction (LPME) as a sample pretreatment technique for the simultaneous analysis of several phytohormones. Using phenetole to fill the pores of hollow fiber as the organic phase, 0.1molL(-1) NaOH solution in the lumen of hollow fiber as the acceptor phase and 1molL(-1) HCl as the donor phase, a simultaneous preconcentration of four target phytohormones was realized. The acceptor phase was finally withdrawn into the microsyringe and directly injected into HPLC for the separation and quantification of the target phytohormones. The factors affecting the extraction efficiency of four phytohormones by HF-LLLME were optimized with orthogonal design experiment, and the data was analyzed by Statistical Product and Service Solutions (SPSS) software. Under the optimized conditions, the enrichment factors for SA, IAA, ABA and JA were 243, 215, 52 and 48, with the detection limits (S/N=3) of 4.6, 1.3, 0.9ngmL(-1) and 8.8 microg mL(-1), respectively. The relative standard deviations (RSDs, n=7) were 7.9, 4.9, 6.8% at 50ngmL(-1) level for SA, IAA, ABA and 8.4% at 500 microg mL(-1) for JA, respectively. To evaluate the accuracy of the method, the developed method was applied for the simultaneous analysis of several phytohormones in five natural coconut juice samples, and the recoveries for the spiked samples were in the range of 88.3-119.1%.

  12. A pre-anodized inlaying ultrathin carbon paste electrode for simultaneous determination of uric acid and folic acid

    International Nuclear Information System (INIS)

    Huo, Jing’e; Shangguan, Enbo; Li, Quanmin

    2013-01-01

    Graphical abstract: In 0.10 mol/L PBS (pH 6.00), oxidation reaction occurred at the PAIUCPE owing to uric acid (UA) loss electrons, while oxygen dissolved in the feed was reduced at the platinum electrode. Furthermore, the effect of electrode reaction at the platinum electrode on that of working electrode is detailedly discussed. Highlights: ► The simultaneous determination of UA and FA is achieved at the PAIUCPE. ► The effect of reaction at the Pt electrode on that of working electrode is discussed. ► The effect of pH on peak currents is detailedly explained for the first time. -- Abstract: A pre-anodized inlaying ultrathin carbon paste electrode (PAIUCPE) was prepared by electrochemical pretreatment. The scanning electron microscope (SEM) was applied to characterize the surface morphology of PAIUCPE and the performance of the electrode was characterized by cyclic voltammetry (CV). The results indicated that PAIUCPE displayed excellent electrocatalysis for the oxidation of uric acid (UA) and folic acid (FA). The separated extent between the two oxidation peaks of UA and FA was 324 mV, which was enough for the simultaneous detection. In 0.10 mol/L PBS (pH 6.00), the linear scan voltammetry (LSV) response of UA and FA increased linearly with the concentration in the range of 4.0 × 10 −6 –3.5 × 10 −4 mol/L and 3.0 × 10 −6 –2.0 × 10 −4 mol/L with the detection limits of 1.1 × 10 −7 mol/L and 1.5 × 10 −7 mol/L, respectively. It was successfully used to determine UA and FA in human urine simultaneously

  13. Method and apparatus for simultaneous determination of fluid mass flow rate, mean velocity and density

    Science.gov (United States)

    Hamel, William R.

    1984-01-01

    This invention relates to a new method and new apparatus for determining fluid mass flowrate and density. In one aspect of the invention, the fluid is passed through a straight cantilevered tube in which transient oscillation has been induced, thus generating Coriolis damping forces on the tube. The decay rate and frequency of the resulting damped oscillation are measured, and the fluid mass flowrate and density are determined therefrom. In another aspect of the invention, the fluid is passed through the cantilevered tube while an electrically powered device imparts steady-state harmonic excitation to the tube. This generates Coriolis tube-damping forces which are dependent on the mass flowrate of the fluid. Means are provided to respond to incipient flow-induced changes in the amplitude of vibration by changing the power input to the excitation device as required to sustain the original amplitude of vibration. The fluid mass flowrate and density are determined from the required change in power input. The invention provides stable, rapid, and accurate measurements. It does not require bending of the fluid flow.

  14. Spectrophotometric methods for simultaneous determination of Carvedilol and Hydrochlorothiazide in combined dosage form

    Directory of Open Access Journals (Sweden)

    Nada S. Abdelwahab

    2016-09-01

    In Method (I, two wavelengths were selected for each drug in such a way that the difference in absorbance is zero for the second drug. At wavelengths 238 and 248.8 nm HCT has equal absorbance values, therefore, these two wavelengths have been used to determine CV, on similar basis 266 and 289.4 nm were selected to determine HCT in the combined formulation. Method (II involves the formation of Q-absorbance equation using the respective absorptivity values at 229.2 nm (isoabsorptive point and 241 nm (λmax of CV. The drugs obey Beer’s Lambert’s law in the concentration range of 1–10 μg/mL for both CV and HCT (for Method I and in the range of 1–10 and 2–10 μg/mL for CV and HCT, respectively (for Method II. The accuracy and precision were determined and recovery studies confirmed the accuracy of the developed methods that were carried out following the International Conference on Harmonization (ICH guidelines. Statistical comparison of the suggested methods with the reported spectrophotometric one using F and t tests showed no significant difference regarding both accuracy and precision.

  15. Method and apparatus for simultaneous determination of fluid mass flow rate, mean velocity and density

    International Nuclear Information System (INIS)

    Hamel, W.R.

    1984-01-01

    This invention relates to a new method and new apparatus for determining fluid mass flow rate and density. In one aspect of the invention, the fluid is passed through a straight cantilevered tube in which transient oscillation has been induced, thus generating Coriolis damping forces on the tube. The decay rate and frequency of the resulting damped oscillation are measured, and the fluid mass flow rate and density are determined therefrom. In another aspect of the invention, the fluid is passed through the cantilevered tube while an electrically powered device imparts steady-state harmonic excitation to the tube. This generates Coriolis tube-damping forces which are dependent on the mass flow rate of the fluid. Means are provided to respond to incipient flow-induced changes in the amplitude of vibration by changing the power input to the excitation device as required to sustain the original amplitude of vibration. The fluid mass flow rate and density are determined from the required change in power input. The invention provides stable, rapid, and accurate measurements. It does not require bending of the fluid flow

  16. A novel paper-based assay for the simultaneous determination of Rh typing and forward and reverse ABO blood groups.

    Science.gov (United States)

    Noiphung, Julaluk; Talalak, Kwanrutai; Hongwarittorrn, Irin; Pupinyo, Naricha; Thirabowonkitphithan, Pannawich; Laiwattanapaisal, Wanida

    2015-05-15

    We propose a new, paper-based analytical device (PAD) for blood typing that allows for the simultaneous determination of ABO and Rh blood groups on the same device. The device was successfully fabricated by using a combination of wax printing and wax dipping methods. A 1:2 blood dilution was used for forward grouping, whereas whole blood could be used for reverse grouping. A 30% cell suspension of A-cells or B-cells was used for haemagglutination on the reverse grouping side. The total assay time was 10 min. The ratio between the distance of red blood cell movement and plasma separation is the criterion for agglutination and indicates the presence of the corresponding antigen or antibody. The proposed PAD has excellent reproducibility in that the same blood groups, namely A, AB, and O, were reported by using different PADs that were fabricated on the same day (n=10). The accuracy for detecting blood group A (n=12), B (n=13), AB (n=9), O (n=14), and Rh (n=48) typing were 92%, 85%, 89%, 93%, and 96%, respectively, in comparison with the conventional slide test method. The haematocrit of the sample affects the accuracy of the results, and appropriate dilution is suggested before typing. In conclusion, this study proposes a novel method that is straightforward, time-saving, and inexpensive for the simultaneous determination of ABO and Rh blood groups, which is promising for use in developing countries. Copyright © 2015 Elsevier B.V. All rights reserved.

  17. Derivative- Ratio Spectrophotometric, Chemometric and HPLC Validated methods for Simultaneous Determination of Amlodipine and Atorvastatin in Combined Dosage Form

    Directory of Open Access Journals (Sweden)

    Ola Moustafa Abdallah

    2011-04-01

    Full Text Available Three methods were developed for simultaneous determination of amlodipine and atorvastatin without previous separation. The first method depends on first derivative of the ratios spectra by measurements of the amplitudes at 228 and 245 nm for amlodipine using 25 μg/mL of atorvastatin as a divisor and at 284 and 295 nm for atorvastatin using 80 μg/mL of amlodipine as a divisor. Calibration graphs were established in the range of 10-100 μg/mL and 2.5-30 μg/mL for amlodipine and atorvastatin, respectively. The second method describes the use of multivariate spectophotometric calibration for the simultaneous determination of the analyzed binary mixture, where the resolution is accomplished by using partial least squares (PLS regression analysis. In the third method (HPLC, separation was performed by using C18 reversed phase column and a mobile phase of acetonitrile: 0.05 M KH2PO4 (60:40v/v adjusted by phosphoric acid to pH 3.5 at flow rate of 1 mL/min. All proposed methods were extensively validated and the results obtained by adopting the three methods were statistically analyzed and compared with those obtained from a reported method.

  18. Development and Validation of HPLC Method for the Simultaneous Determination of Five Food Additives and Caffeine in Soft Drinks

    Directory of Open Access Journals (Sweden)

    Bürge Aşçı

    2016-01-01

    Full Text Available Box-Behnken design was applied to optimize high performance liquid chromatography (HPLC conditions for the simultaneous determination of potassium sorbate, sodium benzoate, carmoisine, allura red, ponceau 4R, and caffeine in commercial soft drinks. The experimental variables chosen were pH (6.0–7.0, flow rate (1.0–1.4 mL/min, and mobile phase ratio (85–95% acetate buffer. Resolution values of all peak pairs were used as a response. Stationary phase was Inertsil OctaDecylSilane- (ODS- 3V reverse phase column (250 × 4.6 mm, 5 μm dimensions. The detection was performed at 230 nm. Optimal values were found 6.0 pH, 1.0 mL/min flow rate, and 95% mobile phase ratio for the method which was validated by calculating the linearity (r2>0.9962, accuracy (recoveries ≥ 95.75%, precision (intraday variation ≤ 1.923%, interday variation ≤ 1.950%, limits of detection (LODs, and limits of quantification (LOQs parameters. LODs and LOQs for analytes were in the range of 0.10–0.19 μg/mL and 0.33–0.63 μg/mL, respectively. The proposed method was applied successfully for the simultaneous determination of the mixtures of five food additives and caffeine in soft drinks.

  19. A simple and rapid fluorimetric method for simultaneous determination of protoporphyrin IX and zinc protoporphyrin IX in whole blood.

    Science.gov (United States)

    Zhou, Pei-Chen; Huang, Wei; Zhang, Rong-Bin; Zou, Zhe-Xiang; Luo, He-Dong; Falih, Ali Abbas; Li, Yao-Qun

    2008-11-01

    Derivative variable-angle synchronous fluorescence (DVASF) spectrometry improves the spectral resolution and selectivity of the fluorescence method. The feasibility of DVASF spectrometry for the simultaneous determination of protoporphyrin IX (PP) and zinc protoporphyrin IX (ZnPP) was investigated. PP and ZnPP were distinguished from each other simultaneously and rapidly by the DVASF method. The spectra were resolved well, and the two components were determined in a single scan, avoiding the spectral compensation factor for PP and chromatographic separation. The linear range of the calibration curve for PP was from 0.190 to 152 nmol/L and for ZnPP was from 0.383 to 230 nmol/L. The detection limits of PP and ZnPP were 0.098 nmol/L and 0.088 nmol/L, respectively. The within-run imprecision (RSD, n = 5) for PP was 4.1%, and for ZnPP was 4.2%. Mean recoveries (SD) of PP and ZnPP added to a blood sample were 86.4 (7.3)% and 72.9 (6.6)%, respectively. This method should be a potential tool in the rapid routine screening of large quantities of samples.

  20. Simultaneous determination of 14N and 15N isotopes in opium by proton induced γ-ray emission technique

    International Nuclear Information System (INIS)

    Pritty Rao; Reddy, G.L.N.; Vikram Kumar, S.; Ramana, J.V.; Raju, V.S.; Sanjiv Kumar

    2012-01-01

    The paper describes the simultaneous determination of 14 N and 15 N isotopes in opium by proton induced γ-ray emission (PIGE) technique. The isotopic ratio of 14 N and 15 N is a useful parameter for assigning provenance of (seized) illicit drugs. The measurement, non-destructive in nature, is performed on pellets made up of opium powders and is based on the prompt detection of 2.313 and 4.4 MeV γ-rays emanating from 14 N(p,p'γ) 14 N and 15 N(p,αγ) 12 C nuclear reactions respectively, induced simultaneously by 3.6-3.8 MeV proton beam. Positive as well as negative deviations from the natural isotopic abundance (99.63:0.37) were observed in the samples. The precision of the measurements is about 4%. The methodology provides an easy and rapid approach to determine the isotopic ratio of 14 N and 15 N and has been used for the first time in the analysis of opium. (author)

  1. Graphene/Nafion composite film modified glassy carbon electrode for simultaneous determination of paracetamol, aspirin and caffeine in pharmaceutical formulations.

    Science.gov (United States)

    Yiğit, Aydın; Yardım, Yavuz; Çelebi, Metin; Levent, Abdulkadir; Şentürk, Zühre

    2016-09-01

    A graphene-Nafion composite film was fabricated on the glassy carbon electrode (GR-NF/GCE), and used for simultaneous determination of paracetamol (PAR), aspirin (ASA) and caffeine (CAF). The electrochemical behaviors of PAR, ASA and CAF were investigated by cyclic voltammetry and square-wave adsorptive anodic stripping voltammetry. By using stripping one for simultaneous determination of PAR, ASA and CAF, their electrochemical oxidation peaks appeared at +0.64, 1.04 and 1.44V, and good linear current responses were obtained with the detection limits of 18ngmL(-1) (1.2×10(-9)M), 11.7ngmL(-1) (6.5×10(-8)M) and 7.3ngmL(-1) (3.8×10(-8)M), respectively. Finally, the proposed electrochemical sensor was successfully applied for quantifying PAR, ASA and CAF in commercial tablet formulations. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. Simultaneous determination of paracetamol and ibuprofen in pharmaceutical samples by differential pulse voltammetry using a boron-doped diamond electrode

    Energy Technology Data Exchange (ETDEWEB)

    Lima, Amanda B.; Guimaraes, Carlos F.R.C.; Verly, Rodrigo M.; Silva, Leonardo M. da [Universidade Federal dos Vales do Jequitinhonha e Mucuri (UFVJM), Diamantina, MG (Brazil). Departamento de Quimica; Torres, Livia M.F.C.; Carvalho Junior, Alvaro D.; Santos, Wallans T. P. dos, E-mail: wallanst@ufvjm.edu.br [Universidade Federal dos Vales do Jequitinhonha e Mucuri (UFVJM), Diamantina, MG (Brazil). Departamento de Farmacia

    2014-03-15

    This work presents a simple, fast and low-cost methodology for the simultaneous determination of paracetamol (PC) and ibuprofen (IB) in pharmaceutical formulations by differential pulse voltammetry using a boron-doped diamond (BDD) electrode. A well-defined oxidation peak was observed using the BDD electrode for each analyte (0.85 V for PC and 1.72 V for IB (vs. Ag/AgCl)) in 0.1 mol L{sup -1} H{sub 2}SO{sub 4} solution containing 10% (v/v) of ethanol. Calibration curves for the simultaneous determination of PC and IB showed a linear response for both drugs in a concentration range of 20 to 400 μmol L{sup -1} (r{sup 2} = 0.999), with a detection limit of 7.1 μmol L{sup -1} for PC and 3.8 μmol L{sup -1} for IB. The addition-recovery studies in samples were about 100% and the results were validated by chromatographic methods. (author)

  3. Simultaneous determination of five active compounds in chimonanthus nitens by double-development HPTLC and scanning densitometry

    Directory of Open Access Journals (Sweden)

    Zhou Bin

    2012-05-01

    Full Text Available Abstract Background Chimonanthus nitens (family Calycanthaceae, Shanlamei in Chinese, is an unique species in China. The extract of dried leaves of Chimonanthus nitens has anti-inflammatory, antipyretic and antitussive effects. Terpenes, coumarins, and flavonoids are usually regarded as the main active components. Therefore, simultaneous determination of these compounds is very important to control the quality of Chimonanthus nitens. Results A double-development TLC method was developed for simultaneous analysis of five compounds in Chimonanthus nitens. The chromatography was performed on silica gel 60 plate with chloroform-methanol (9∶1, v/v and petroleum ether-ethyl acetate (10∶1, v/v as mobile phase for twice development. Their characteristic TLC profiles were observed under UV light at 365 nm and the bands were then revealed by reaction with 1% vanillin-H2SO4 solution. Quantification of three monoterpenes was achieved by densitometry at 545 nm (β-caryophyllene or 606 nm (cineole and linalool. Two coumarins (scopoletin and scoparone were determined by densitometry at 340 nm with filter wavelength of 370 nm. The investigated compounds had good linearity (R2 >0.99 within test ranges. Conclusions The developed double-development TLC method is helpful to control the quality of Chimonanthus nitens, which is simple and accurate.

  4. Simultaneous determination of five active compounds in chimonanthus nitens by double-development HPTLC and scanning densitometry

    Science.gov (United States)

    2012-01-01

    Background Chimonanthus nitens (family Calycanthaceae), Shanlamei in Chinese, is an unique species in China. The extract of dried leaves of Chimonanthus nitens has anti-inflammatory, antipyretic and antitussive effects. Terpenes, coumarins, and flavonoids are usually regarded as the main active components. Therefore, simultaneous determination of these compounds is very important to control the quality of Chimonanthus nitens. Results A double-development TLC method was developed for simultaneous analysis of five compounds in Chimonanthus nitens. The chromatography was performed on silica gel 60 plate with chloroform-methanol (9∶1, v/v) and petroleum ether-ethyl acetate (10∶1, v/v) as mobile phase for twice development. Their characteristic TLC profiles were observed under UV light at 365 nm and the bands were then revealed by reaction with 1% vanillin-H2SO4 solution. Quantification of three monoterpenes was achieved by densitometry at 545 nm (β-caryophyllene) or 606 nm (cineole and linalool). Two coumarins (scopoletin and scoparone) were determined by densitometry at 340 nm with filter wavelength of 370 nm. The investigated compounds had good linearity (R2 >0.99) within test ranges. Conclusions The developed double-development TLC method is helpful to control the quality of Chimonanthus nitens, which is simple and accurate. PMID:22616568

  5. Graphene/polyvinylpyrrolidone/polyaniline nanocomposite-modified electrode for simultaneous determination of parabens by high performance liquid chromatography.

    Science.gov (United States)

    Kajornkavinkul, Suphunnee; Punrat, Eakkasit; Siangproh, Weena; Rodthongkum, Nadnudda; Praphairaksit, Narong; Chailapakul, Orawon

    2016-02-01

    A nanocomposite of graphene (G), polyvinylpyrrolidone (PVP) and polyaniline (PANI) modified onto screen-printed carbon electrode (SPCE) using an electrospraying technique was developed for simultaneous determination of five parabens in beverages and cosmetic products by high performance liquid chromatography. PVP and PANI were used as the dispersing agents of graphene, and also for the enhancement of electrochemical conductivity of the electrode. The electrochemical behavior of each paraben was investigated using the G/PVP/PANI nanocomposite-modified SPCE, compared to the unmodified SPCE. Using HPLC along with amperometric detection at a controlled potential of +1.2V vs Ag/AgCl, the chromatogram of five parabens obtained from the modified SPCE exhibits well defined peaks and higher current response than those of its unmodified counterpart. Under the optimal conditions, the calibration curves of five parabens similarly provide a linear range between 0.1 and 30 µg mL(-1) with the detection limits of 0.01 µg mL(-1) for methyl paraben (MP), ethyl paraben (EP) and propyl paraben (PP), 0.02 and 0.03 µg mL(-1) for isobutyl paraben (IBP) and butyl paraben (BP), respectively. Furthermore, this proposed method was applied for the simultaneous determination of five parabens in real samples including a soft drink and a cosmetic product with satisfactory results, yielding the recovery in the range of 90.4-105.0%. Copyright © 2015 Elsevier B.V. All rights reserved.

  6. Simultaneous determination of paracetamol and ibuprofen in pharmaceutical samples by differential pulse voltammetry using a boron-doped diamond electrode

    International Nuclear Information System (INIS)

    Lima, Amanda B.; Guimaraes, Carlos F.R.C.; Verly, Rodrigo M.; Silva, Leonardo M. da; Torres, Livia M.F.C.; Carvalho Junior, Alvaro D.; Santos, Wallans T. P. dos

    2014-01-01

    This work presents a simple, fast and low-cost methodology for the simultaneous determination of paracetamol (PC) and ibuprofen (IB) in pharmaceutical formulations by differential pulse voltammetry using a boron-doped diamond (BDD) electrode. A well-defined oxidation peak was observed using the BDD electrode for each analyte (0.85 V for PC and 1.72 V for IB (vs. Ag/AgCl)) in 0.1 mol L -1 H 2 SO 4 solution containing 10% (v/v) of ethanol. Calibration curves for the simultaneous determination of PC and IB showed a linear response for both drugs in a concentration range of 20 to 400 μmol L -1 (r 2 = 0.999), with a detection limit of 7.1 μmol L -1 for PC and 3.8 μmol L -1 for IB. The addition-recovery studies in samples were about 100% and the results were validated by chromatographic methods. (author)

  7. Simultaneous determination of water-soluble vitamins in selected food matrices by liquid chromatography/electrospray ionization tandem mass spectrometry.

    Science.gov (United States)

    Gentili, Alessandra; Caretti, Fulvia; D'Ascenzo, Giuseppe; Marchese, Stefano; Perret, Daniela; Di Corcia, Daniele; Rocca, Lucia Mainero

    2008-07-01

    A rapid, simple and sensitive method based on liquid chromatography/tandem mass spectrometry (LC/MS/MS) with an electrospray ionization (ESI) source for the simultaneous analysis of fourteen water-soluble vitamins (B1, B2, two B3 vitamers, B5, five B6 vitamers, B8, B9, B12 and C) in various food matrices, i.e. maize flour, green and golden kiwi and tomato pulp, is presented here. Analytes were separated by ion-suppression reversed-phase liquid chromatography in less than 10 min and detected in positive ion mode. Sensitivity and specificity of this method allowed two important results to be achieved: (i) limits of detection of the analytes at ng g(-1) levels (except for vitamin C); (ii) development of a rapid sample treatment that minimizes analyte exposition to light, air and heat, eliminating any step of extract concentration. Analyte recovery depended on the type of matrix. In particular, recovery of the analytes in maize flour was > or =70%, with the exception of vitamin C, pyridoxal-5'-phosphate and vitamin B9 (ca 40%); with tomato pulp, recovery was > or =64%, except for vitamin C (41%); with kiwi, recovery was > or =73%, except for nicotinamide (ca. 30%).

  8. Modification of carbon paste electrode with Fe(III)-clinoptilolite nano-particles for simultaneous voltammetric determination of acetaminophen and ascorbic acid

    Energy Technology Data Exchange (ETDEWEB)

    Sharifian, Samira [Department of Chemistry, Shahreza Branch, Islamic Azad University, P.O. Box 311-86145, Shahreza, Isfahan (Iran, Islamic Republic of); Young Researchers and Elite Club, Shahreza Branch, Islamic Azad University, Shahreza (Iran, Islamic Republic of); Nezamzadeh-Ejhieh, Alireza, E-mail: arnezamzadeh@iaush.ac.ir [Department of Chemistry, Shahreza Branch, Islamic Azad University, P.O. Box 311-86145, Shahreza, Isfahan (Iran, Islamic Republic of); Young Researchers and Elite Club, Shahreza Branch, Islamic Azad University, Shahreza (Iran, Islamic Republic of); Razi Chemistry Research Center (RCRC), Shahreza Branch, Islamic Azad University, Isfahan (Iran, Islamic Republic of)

    2016-01-01

    A novel carbon paste electrode (CPE) modified with Fe(III)-exchanged clinoptilolite nano-particles (Fe(III)-NClino/CPE) was constructed and used for simultaneous voltammetric (CV, SqW and chronoamperometry) determination of ascorbic acid and acetaminophen. Raw and modified zeolites were characterized by X-ray diffraction (XRD) and transmission electron microscope (TEM). The square wave peak current was linearly increased in the concentration ranges of 1.0 × 10{sup −9}–1.0 × 10{sup −2} mol L{sup −1} for ascorbic acid and 1.0 × 10{sup –10–}1.0 × 10{sup −2} mol L{sup −1} for acetaminophen with detection limits of 1.8 × 10{sup −9} mol L{sup −1} and 9.9 × 10{sup −10} mol L{sup −1}, respectively. The detection limits of 2.4 × 10{sup −10} mol L{sup −1} and 2.5 × 10{sup −11} mol L{sup −1} were also obtained for AA and AC in chronoamperometric measurements, respectively. The diffusion coefficients of 7.5 × 10{sup −5} cm{sup 2} s{sup −1} and 2.4 × 10{sup −5} cm{sup 2} s{sup −1} were respectively calculated for the oxidation of AC and AA by chronoamperometry. The proposed electrode exhibited high sensitivity and good stability, and would be valuable for the clinical assay of ascorbic acid and acetaminophen. - Graphical abstract: Comparison of CV voltammograms of the raw CPE (‘a’ and ‘b’) and the modified Fe(III)-NClino-CPE (‘c’ and ‘d’) confirmed good electrocatalytic activity of the modified electrode for voltammetric determination of AC and AA, so the peak currents significantly increased in presence of AA or AC species in solution (‘c’ and ‘d’). - Highlights: • Usefulness of Fe(III)-Nclino for simultaneous voltammetric determination of AA + AC • Electrocatalytic behavior of the electrode for AA determination • Complexation behavior of the electrode for AC determination • Considerable increase in sensitivity of the process • More efficient of nanonized clinoptilolite than the micronized one.

  9. Simultaneous determination of moxifloxacin and cefixime by first and ratio first derivative ultraviolet spectrophotometry

    Science.gov (United States)

    2012-01-01

    Background The new combination of moxifloxacin HCl and cefixime trihydrate is approved for the treatment of lower respiratory tract infections in adults. At initial formulation development and screening stage a fast and reliable method for the dissolution and release testing of moxifloxacin and cefixime were highly desirable. The zero order overlaid UV spectra of moxifloxacin and cefixime showed >90% overlapping. Hence, simple, accurate precise and validated two derivative spectrophotometric methods have been developed for the determination of moxifloxacin and cefixime. Methods In the first derivative spectrophotometric method varying concentration of moxifloxacin and cefixime were prepared and scanned in the range of 200 to 400 nm and first derivative spectra were calculated (n = 1). The zero crossing wavelengths 287 nm and 317.9 nm were selected for determination of moxifloxacin and cefixime, respectively. In the second method the first derivative of ratio spectra was calculated and used for the determination of moxifloxacin and cefixime by measuring the peak intensity at 359.3 nm and 269.6 nm respectively. Results Calibration graphs were established in the range of 1–16 μg /mL and 1–15 μg /mL for both the drugs by first and ratio first derivative spectroscopic methods respectively with good correlation coefficients. Average accuracy of assay of moxifloxacin and cefixime were found to be 100.68% and 98 93%, respectively. Relative standard deviations of both inter and intraday assays were less than 1.8%. Moreover, recovery of moxifloxacin and cefixime was more than 98.7% and 99.1%, respectively. Conclusions The described derivative spectrophotometric methods are simple, rapid, accurate, precise and excellent alternative to sophisticated chromatographic techniques. Hence, the proposed methods can be used for the quality control of the cited drugs and can be extended for routine analysis of the drugs in formulations. PMID:22995678

  10. Rapid and simultaneous determination of Strontium-89 and Strontium-90 in seawater.

    Science.gov (United States)

    Tayeb, Michelle; Dai, Xiongxin; Sdraulig, Sandra

    2016-03-01

    A rapid method has been developed for the direct determination of radiostrontium ((89)Sr and (90)Sr) released in seawater in the early phase of an accident. The method employs a fast and effective pre-concentration of radiostrontium by Sr-Ca co-precipitation followed by separation of radiostrontium using extraction chromatography technique. Radiostrontium is effectively separated in the presence of excessive dominant salts of seawater. Čerenkov and liquid scintillation assay (LSA) techniques are used to determine (89)Sr and (90)Sr. Sample preparation time is approximately 4 h for a set of 10 samples. The method was validated using spiked seawater samples at various activity ratios of (89)Sr:(90)Sr ranging from 1:10 to 9:1. The mean chemical recovery of Sr was 85 ± 3%. (90)Sr showed variable relative bias which enhanced with increasing ratio of (89)Sr:(90)Sr and was in the range ± 21%. The highest biases of (90)Sr determination were due to lower activity concentrations of (90)Sr and are regarded as acceptable in emergency situations with elevated levels of radiostrontium in the sample. The minimum detectable concentration (MDC) of (90)Sr and (89)Sr varied at different (89)Sr:(90)Sr ratios. For 0.1 L seawater and 15 min counting time on a low background Hidex liquid scintillation counter (LSC), the MDC of (90)Sr was in the range of 1.7-3.5 Bq L(-1) and MDC of (89)Sr was in the range 0.5-2.4 Bq L(-1). Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Simultaneous determination of stable carbon, oxygen, and hydrogen isotopes in cellulose.

    Science.gov (United States)

    Loader, N J; Street-Perrott, F A; Daley, T J; Hughes, P D M; Kimak, A; Levanič, T; Mallon, G; Mauquoy, D; Robertson, I; Roland, T P; van Bellen, S; Ziehmer, M M; Leuenberger, M

    2015-01-06

    A technological development is described through which the stable carbon-, oxygen-, and nonexchangeable hydrogen-isotopic ratios (δ(13)C, δ(18)O, δ(2)H) are determined on a single carbohydrate (cellulose) sample with precision equivalent to conventional techniques (δ(13)C 0.15‰, δ(18)O 0.30‰, δ(2)H 3.0‰). This triple-isotope approach offers significant new research opportunities, most notably in physiology and medicine, isotope biogeochemistry, forensic science, and palaeoclimatology, when isotopic analysis of a common sample is desirable or when sample material is limited.

  12. Simultaneous determination of twelve trace elements in estuarine and sea water using pre-irradiation chromatography

    International Nuclear Information System (INIS)

    Greenberg, R.R.; Kingston, H.M.

    1982-01-01

    A procedure is described for the preconcentration of 100 m of estuarine and seawater into a solid sample using Chelex-100 resin. This solid sample weighs less than half a gram and contains the transition metals and many other elements of interest, but is essentially free from the alkali metals, the alkaline earth metals, and the halogens. The concentrations of Co, Cr, Cu, Fe, Mn, Mo, Ni, Sc, Th, U, V and Zn have been determined in seawater when this procedure was coupled to neutron activation analysis. (author)

  13. Chemometrics-Assisted UV Spectrophotometric and RP-HPLC Methods for the Simultaneous Determination of Tolperisone Hydrochloride and Diclofenac Sodium in their Combined Pharmaceutical Formulation

    Science.gov (United States)

    Gohel, Nikunj Rameshbhai; Patel, Bhavin Kiritbhai; Parmar, Vijaykumar Kunvarji

    2013-01-01

    Chemometrics-assisted UV spectrophotometric and RP-HPLC methods are presented for the simultaneous determination of tolperisone hydrochloride (TOL) and diclofenac sodium (DIC) from their combined pharmaceutical dosage form. Chemometric methods are based on principal component regression and partial least-square regression models. Two sets of standard mixtures, calibration sets, and validation sets were prepared. Both models were optimized to quantify each drug in the mixture using the information included in the UV absorption spectra of the appropriate solution in the range 241–290 nm with the intervals λ = 1 nm at 50 wavelengths. The optimized models were successfully applied to the simultaneous determination of these drugs in synthetic mixture and pharmaceutical formulation. In addition, an HPLC method was developed using a reversed-phase C18 column at ambient temperature with a mobile phase consisting of methanol:acetonitrile:water (60:30:10 v/v/v), pH-adjusted to 3.0, with UV detection at 275 nm. The methods were validated in terms of linearity, accuracy, precision, sensitivity, specificity, and robustness in the range of 3–30 μg/mL for TOL and 1–10 μg/mL for DIC. The robustness of the HPLC method was tested using an experimental design approach. The developed HPLC method, and the PCR and PLS models were used to determine the amount of TOL and DIC in tablets. The data obtained from the PCR and PLS models were not significantly different from those obtained from the HPLC method at 95% confidence limit. PMID:24482768

  14. Eco-friendly ionic liquid assisted capillary electrophoresis and α-acid glycoprotein-assisted liquid chromatography for simultaneous determination of anticancer drugs in human fluids.

    Science.gov (United States)

    Abd El-Hady, Deia; Albishri, Hassan M; Rengarajan, Rajesh

    2015-06-01

    In the current work, two eco-friendly analytical methods based on capillary electrophoresis (CE) and reversed phase liquid chromatography (RPLC) were developed for simultaneous determination of the most commonly used anticancer drugs for Hodgkin's disease: methotrexate (MTX), vinblastine, chlorambucil and dacarbazine. A background electrolyte (BGE) of 12.5 mmol/L phosphate buffer at pH 7.4 and 0.1 µmol/L 1-butyl-3-methyl imidazolium bromide (BMImBr) ionic liquid (IL) was used for CE measurements at 250 nm detection wavelength, 20 kV applied voltage and 25 °C. The rinsing protocol was significantly improved to reduce the adsorption of IL on the interior surface of capillary. Moreover, RPLC method was developed on α-1-acid glycoprotein (AGP) column. Mobile phase was 10 mmol/L phosphate buffer at pH 6.0 (100% v/v) and flow rate at 0.1 mL/min. As AGP is a chiral column, it was successfully separated l-MTX from its enantiomer impurity d-MTX. Good linearity of quantitative analysis was achieved with coefficients of determinations (r(2) ) >0.995. The stability of drugs measurements was investigated with adequate recoveries up to 24 h storage time under ambient temperature. The limits of detection were <50 and 90 ng/mL by CE and RPLC, respectively. The using of short-chain IL as an additive in BGE achieved 600-fold sensitivity enhancement compared with conventional Capillary Zone Electrophoresis (CZE). Therefore, for the first time, the proposed methods were successfully applied to determine simultaneously the analytes in human plasma and urine samples at clinically relevant concentrations with fast and simple pretreatments. Developed IL-assisted CE and RPLC methods were also applied to measure MTX levels in patients' samples over time. Copyright © 2014 John Wiley & Sons, Ltd.

  15. Chemometrics-Assisted UV Spectrophotometric and RP-HPLC Methods for the Simultaneous Determination of Tolperisone Hydrochloride and Diclofenac Sodium in their Combined Pharmaceutical Formulation.

    Science.gov (United States)

    Gohel, Nikunj Rameshbhai; Patel, Bhavin Kiritbhai; Parmar, Vijaykumar Kunvarji

    2013-01-01

    Chemometrics-assisted UV spectrophotometric and RP-HPLC methods are presented for the simultaneous determination of tolperisone hydrochloride (TOL) and diclofenac sodium (DIC) from their combined pharmaceutical dosage form. Chemometric methods are based on principal component regression and partial least-square regression models. Two sets of standard mixtures, calibration sets, and validation sets were prepared. Both models were optimized to quantify each drug in the mixture using the information included in the UV absorption spectra of the appropriate solution in the range 241-290 nm with the intervals λ = 1 nm at 50 wavelengths. The optimized models were successfully applied to the simultaneous determination of these drugs in synthetic mixture and pharmaceutical formulation. In addition, an HPLC method was developed using a reversed-phase C18 column at ambient temperature with a mobile phase consisting of methanol:acetonitrile:water (60:30:10 v/v/v), pH-adjusted to 3.0, with UV detection at 275 nm. The methods were validated in terms of linearity, accuracy, precision, sensitivity, specificity, and robustness in the range of 3-30 μg/mL for TOL and 1-10 μg/mL for DIC. The robustness of the HPLC method was tested using an experimental design approach. The developed HPLC method, and the PCR and PLS models were used to determine the amount of TOL and DIC in tablets. The data obtained from the PCR and PLS models were not significantly different from those obtained from the HPLC method at 95% confidence limit.

  16. Novel two wavelength spectrophotometric methods for simultaneous determination of binary mixtures with severely overlapping spectra

    Science.gov (United States)

    Lotfy, Hayam M.; Saleh, Sarah S.; Hassan, Nagiba Y.; Salem, Hesham

    2015-02-01

    This work presents the application of different spectrophotometric techniques based on two wavelengths for the determination of severely overlapped spectral components in a binary mixture without prior separation. Four novel spectrophotometric methods were developed namely: induced dual wavelength method (IDW), dual wavelength resolution technique (DWRT), advanced amplitude modulation method (AAM) and induced amplitude modulation method (IAM). The results of the novel methods were compared to that of three well-established methods which were: dual wavelength method (DW), Vierordt's method (VD) and bivariate method (BV). The developed methods were applied for the analysis of the binary mixture of hydrocortisone acetate (HCA) and fusidic acid (FSA) formulated as topical cream accompanied by the determination of methyl paraben and propyl paraben present as preservatives. The specificity of the novel methods was investigated by analyzing laboratory prepared mixtures and the combined dosage form. The methods were validated as per ICH guidelines where accuracy, repeatability, inter-day precision and robustness were found to be within the acceptable limits. The results obtained from the proposed methods were statistically compared with official ones where no significant difference was observed. No difference was observed between the obtained results when compared to the reported HPLC method, which proved that the developed methods could be alternative to HPLC techniques in quality control laboratories.

  17. Simultaneous multi-element determination in some cosmetic samples of different origins using neutron activation analysis

    International Nuclear Information System (INIS)

    El-Shazly, E.A.A.; Abo Zahra, S.F.; El-Sweify, F.H.; Kanias, G.D.

    2004-01-01

    Instrumental neutron activation analysis (INAA) has been used to determine some trace, minor and major elements in some cosmetic samples. These samples have been randomly selected from the Egyptian market. Some of these cosmetics are imported from the world market and the others are manufactured in Egypt. Up to 25 elements have been quantitatively determined in selected cosmetic samples. These elements are: As, Br, Ba, Ce, Co, Cr, Cs, Eu, Fe, Hf, K, La, Lu, Na, Sb, Sc, Sm, Rb, Ta, Tb, Th, U, W, Yb and Zn. Two certified standard reference materials have been used to assure the accuracy and precision of the technique, which are IAEA-405 and SL-1. Two different γ-radioactivity counting systems have been used and compared. Some of the analyzed samples contain some elements, which according to the list of the European Union must not be present in cosmetics. Moreover, some of these elements are present in a very high concentration. Thus, some of the analyzed samples contain arsenic, antimony, chromium and cobalt with the following respectively concentration ranges, in ppm, 0.37-3.67, 0.14-5.36, 2.94-29 768 (∝ 3%) and 0.52-4.12. (orig.)

  18. Simultaneous determination of sulphaquinoxaline and amprolium in veterinary mixture by HPLC and first derivative ultraviolet spectrophotometry

    International Nuclear Information System (INIS)

    El-Sattar, Osama Abd

    2002-01-01

    Two simple and reliable methods are described for the determination of sulphaquinoxaline (SQX) and amprolium (AMP) combined in veterinary powder. The first method depends on high performance liquid chromatography on a reversed phase column (Bondapak-C18) using mobile phase consisting of acetonitrile-methanol-water-phosphoric acid (30: 5: 55: 0.7, by volumes) at a flow rate of 1 ml min with UV detection at 254 nm. The detection limits were 0.2 ug ml and 0.35 ug ml and linearity ranges were 2-20 ug ml and 4-40ug ml for SQX and AMP, respectively. The second one deals with the first derivative (D) spectrophotometry with zero-crossing measurement at 253 nm and 226 nm for SQX and AMP respectively. The detection limits were 0.3 ug ml and linearity ranges were 1-18 ug ml and 4-32 ug-ml for SQX and AMP respectively. The proposed procedures were successfully applied to the determination of these drugs in laboratory prepared mixtures with mean percentage recovery ranged from 98.50 to 99.75 and in commercial preparation ranged from 103.85 to 104.85. (author)

  19. Vapor permeation-stepwise injection simultaneous determination of methanol and ethanol in biodiesel with voltammetric detection.

    Science.gov (United States)

    Shishov, Andrey; Penkova, Anastasia; Zabrodin, Andrey; Nikolaev, Konstantin; Dmitrenko, Maria; Ermakov, Sergey; Bulatov, Andrey

    2016-02-01

    A novel vapor permeation-stepwise injection (VP-SWI) method for the determination of methanol and ethanol in biodiesel samples is discussed. In the current study, stepwise injection analysis was successfully combined with voltammetric detection and vapor permeation. This method is based on the separation of methanol and ethanol from a sample using a vapor permeation module (VPM) with a selective polymer membrane based on poly(phenylene isophtalamide) (PA) containing high amounts of a residual solvent. After the evaporation into the headspace of the VPM, methanol and ethanol were transported, by gas bubbling, through a PA membrane to a mixing chamber equipped with a voltammetric detector. Ethanol was selectively detected at +0.19 V, and both compounds were detected at +1.20 V. Current subtractions (using a correction factor) were used for the selective determination of methanol. A linear range between 0.05 and 0.5% (m/m) was established for each analyte. The limits of detection were estimated at 0.02% (m/m) for ethanol and methanol. The sample throughput was 5 samples h(-1). The method was successfully applied to the analysis of biodiesel samples. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. [Simultaneous determination of two saponnins in anemarrhenae rhizoma by HPLC-ELSD].

    Science.gov (United States)

    Chen, Qianliang; Sun, Xiaoming; Wang, Wenquan; Ma, Changhua

    2011-02-01

    To establish an HPLC-ELSD method for determination of Anemarsaponin C and Anemarsaponin A III in Anemarrhenae Rhizoma. Kromasil C18 column(4.6 mm x 250 mm, 5 microm) was used as stationary phase. Mobile phase was methanol-water gradient with the flow rate of 1 mL x min(-1); the temperature of the drift tube and evaporation was 50 degrees C and 70 degrees C respectively. The gas pressure was 1.03 x 10(5) Pa. There are good linearity in the range 0.310-3.10 microg of anemarsaponin C (lgA = 1.254 2lgM + 5.734 7, r = 0.999 5) and in the range 0.323-3.23 microg (lgA = 1.328 41gM + 5. 937, r = 0.999 6) of anemarsaponin A III. The average recovery of anemarsaponin C and anemarsaponin A III was 98.1% with RSD 2.1% and 97.3% with RSD 1.5% (n = 6) respectively. The method is rapid and accurate. It is suitable for quality control of Anemarrhenae Rhizoma. The result of determination reveals that the quality of Anemarrhenae Rhizoma from different places of north China are of notable difference.

  1. Reagent-free simultaneous determination of glucose and cholesterol in whole blood by FTIR-ATR

    Science.gov (United States)

    Li, Zhigang; Lv, Hong; Li, Tianhe; Si, Guangyuan; Wang, Qiaoyun; Lv, Jiangtao; Hu, Xiaofei

    2017-05-01

    Reagent-free determination of multiple analytes is an active and promising field of research in clinical analysis. In this work, the determination of glucose and cholesterol in whole blood using Fourier transform infrared (FTIR) spectroscopy equipped with an attenuated total reflectance (ATR) accessory was performed. A comprehensive sample selection rule in multi space based on SPXY was proposed, termed C-SPXY. The core idea is to make full use of different derivative spectra space to construct the calibration set which preserves the more effective information. On this basis, a partial least squares (PLS) regression fusion modeling method was also presented aiming at improving prediction accuracy of glucose and cholesterol concentration in whole blood samples. Compared with other methods based on single spectra space, the proposed fusion model based on multi spectra space C-SPXY method provides smaller RMSEP values. Experimental results demonstrate that the proposed method and model provides superior predictive power and holds a good application prospect in the field of clinical analysis.

  2. Simultaneous determination of eight major bioactive compounds in Dachengqi Tang (DT by high-performance liquid chromatography

    Directory of Open Access Journals (Sweden)

    Chen Guanyuan

    2008-04-01

    Full Text Available Abstract Background Dachengqi Tang (DT is a common traditional Chinese medicine formula for expelling neire ('internal heat' in the stomach and intestines. There was no reliable analytical method available for the quality control of DT. Methods A high-performance liquid chromatography (HPLC method with a reverse phase C18 column (150 × 4.6 mm was developed. The mobile phase was methanol with 0.2% acetic acid. Eight markers including naringin, hesperidin, aloe emodin, rhein, honokiol, magnolol, emodin and chrysophanol were determined. Results Regression analysis revealed a linear relationship between the concentrations of the markers and the peak area ratio of the standards and internal standard. The limit of detection (S/N = 3 and the limit of qualification (RSD Conclusion A reliable HPLC method for simultaneous determination of the eight markers in DT was developed.

  3. Simultaneous determination of acetylsalicylic acid, paracetamol and caffeine using solid-phase molecular fluorescence and parallel factor analysis.

    Science.gov (United States)

    Alves, Julio Cesar L; Poppi, Ronei J

    2009-05-29

    This paper describes the determination of acetylsalicylic acid (ASA), paracetamol and caffeine in pharmaceutical formulations using solid-phase molecular fluorescence and second order multivariate calibration. This methodology is applicable even in the presence of unknown interferences and with spectral overlap of the components in the mixture. Parallel factor analysis (PARAFAC) was used for model development, whose effectiveness was demonstrated by analysis of variance (ANOVA). Errors below 10% were obtained for all compounds using an external validation set. Benefits of the new procedures not included in the reference methods such as low cost, no need of sample preparation, simple and fast analysis using fluorescence spectrometer and no generation of waste, make this method very attractive, allowing for the simultaneous determination of compounds with good reproducibility and accuracy.

  4. Simultaneous determination of enalapril maleate and hydrochlorothiazide by first-derivative ultraviolet spectrophotometry and high-performance liquid chromatography.

    Science.gov (United States)

    el Walily, A F; Belal, S F; Heaba, E A; el Kersh, A

    1995-06-01

    Two methods are described for the simultaneous determination of enalapril maleate and hydrochlorothiazide in combined pharmaceutical tablets. The first method depends on first-derivative ultraviolet spectrophotometry, with zero-crossing and peak-to-base measurement methods. The first-derivative amplitudes at 224 and 260 nm were selected for the assay of enalapril maleate and hydrochlorothiazide, respectively. The second method is based on high-performance liquid chromatography on a reversed-phase column using a mobile phase of acetonitrile-water (20:80, v/v) (pH 3.8) with programmable detection at 215 and 275 nm. Both methods showed good linearity, precision and reproducibility. The proposed methods were successfully applied to the determination of these drugs in laboratory-prepared mixtures and in commercial tablets.

  5. Simultaneous determination of aerosol optical thickness and water-leaving radiance from multispectral measurements in coastal waters

    Science.gov (United States)

    Shi, Chong; Nakajima, Teruyuki

    2018-03-01

    Retrieval of aerosol optical properties and water-leaving radiance over ocean is challenging since the latter mostly accounts for ˜ 10 % of the satellite-observed signal and can be easily influenced by the atmospheric scattering. Such an effort would be more difficult in turbid coastal waters due to the existence of optically complex oceanic substances or high aerosol loading. In an effort to solve such problems, we present an optimization approach for the simultaneous determination of aerosol optical thickness (AOT) and normalized water-leaving radiance (nLw) from multispectral satellite measurements. In this algorithm, a coupled atmosphere-ocean radiative transfer model combined with a comprehensive bio-optical oceanic module is used to jointly simulate the satellite-observed reflectance at the top of atmosphere and water-leaving radiance just above the ocean surface. Then, an optimal estimation method is adopted to retrieve AOT and nLw iteratively. The algorithm is validated using Aerosol Robotic Network - Ocean Color (AERONET-OC) products selected from eight OC sites distributed over different waters, consisting of observations that covered glint and non-glint conditions from the Moderate Resolution Imaging Spectroradiometer (MODIS) instrument. Results show a good consistency between retrieved and in situ measurements at each site. It is demonstrated that more accurate AOTs are determined based on the simultaneous retrieval method, particularly in shorter wavelengths and sunglint conditions, where the averaged percentage difference (APD) of retrieved AOT is generally reduced by approximate 10 % in visible bands compared with those derived from the standard atmospheric correction (AC) scheme, since all the spectral measurements can be used jointly to increase the information content in the inversion of AOT, and the wind speed is also simultaneously retrieved to compensate the specular reflectance error estimated from the rough ocean surface model. For the

  6. Simultaneous determination of different endogenetic plant growth regulators in common green seaweeds using dispersive liquid-liquid microextraction method.

    Science.gov (United States)

    Gupta, Vishal; Kumar, Manoj; Brahmbhatt, Harshad; Reddy, C R K; Seth, Abhiram; Jha, Bhavanath

    2011-11-01

    A simple and rapid HPLC-based method was developed for simultaneous determination of major classes of plant growth regulators (PGRs) in Monostroma and different species of Ulva. The plant growth regulators determined included gibberellic acid (GA(3)), indole-3-acetic acid (IAA), abscisic acid (ABA), indole-3-butyric acid (IBA), salicylic acid and kinetin riboside (KR) and their respective elution time was 2.75, 3.3, 3.91, 4.95, 5.39 and 6.59 min. The parameters optimized for distinct separation of PGRs were mobile phase (60:40 methanol and 0.6% acetic acid in water), column temperature (35°C) and flow rate (1ml/min). This method presented an excellent linearity (0.2-100μg/ml) with limit of detection (LOD) as 0.2μg/ml for ABA, 0.5μg/ml for KR and salicylic acid, and 1μg/ml for IAA, IBA and GA(3). The precision and accuracy of the method was evaluated after inter and intra day analysis in triplicates. The effect of plant matrix was compensated after spiking and the resultant recoveries estimated were in the range of 80-120%. Each PGR thereby detected were further characterized by ESI-MS analysis. The method optimized in this study determined IBA along with IAA for the first time in the seaweed species investigated except Ulva linza where the former was not detected. In all the species studied, ABA level was detected to be the highest while kinetin riboside was the lowest. In comparison to earlier methods of PGR analysis, sample preparation and analysis time were substantially reduced while allowing determination of more classes of PGRs simultaneously. Copyright © 2011 Elsevier Masson SAS. All rights reserved.

  7. Simultaneous Determination of Lactulose and Lactose in Conserved Milk by HPLC-RID

    Directory of Open Access Journals (Sweden)

    Michelle Fernandes Silveira

    2015-01-01

    Full Text Available Heat treatment is applied to dairy products to ensure microbiological quality and increase the shelf life. However, a suitable control of this process is necessary to guarantee nutritional and sensory quality. The aim of this study is to adapt the high performance liquid chromatography (HPLC method for determination of lactulose and lactose content in commercial samples of UHT and sweetened condensed milk. The HPLC method used showed a good resolution of the analytes evaluated. The analyzed UHT milk samples presented levels for lactulose in accordance with the limit recommended by the International Dairy Federation. There was no significant variation in lactulose concentration for sweetened condensed milk samples. However, one sweetened condensed milk sample showed lactose level lower than the established values (10–12%.

  8. Simultaneous determination of acetylsalicylic and salicylic acids by first derivative spectrometry in pharmaceutical preparations

    Science.gov (United States)

    Rogić, Dunja

    1993-03-01

    A multicomponent first derivative UV spectrometric procedure for determination of acetylsalicylic acid (aspirin) and salicylic acid in the solution containing 1 % (w/v) of citric acid in some pharmaceutical preparations is presented. The method is based on the use of the first derivative minimum spectrometric measurements at 286 nm for aspirin and at 318 nm for salicylic acid. Four kinds of cmmercial Aspirin tablets were assayed without a long pretreatment of the pharmaceuticals from the tablet additives. Beer's law is obeyed from 13.62-68.1 μg ml -1 of aspirin and from 2.723-13.616 μg ml -1 of salicylic acid. Detection limits at the 0.05 level of significance were calculated to be 1.24 and 0.25 μg ml -1 with relative standard deviations of 1.09 % and 1.2 % of aspirin and salicylic acid, respectively.

  9. High speed radiation scanning technique for simultaneously determining the pitch and eccentricity of an encased coil

    International Nuclear Information System (INIS)

    Foster, B.E.

    1976-01-01

    A method of determining the pitch and eccentricity of the winding of a coil unit is provided. It specifically relates to nondestructively examining completely encased heating coils used to simulate the heat generated from fuel rods in reactor studies. The method comprises (1) the use of an x-ray transmission technique through the axial centerline of the coil unit after the winding of the coil unit has been completely encased, (2) the use of a radiation detection instrument to monitor the transmitted radiation, and (3) the use of recording instrumentation calibrated as a function of the distance between windings. A change in the pitch of the winding is detected by a general increase or decrease in the distance between recorded peaks of the transmitted radiation. Eccentricity is detected by a consistent variation in distance between peaks occurring in alternate pairs. 1 claim, 5 figures

  10. Simultaneous determination of equivalence volumes and acid dissociation constants from potentiometric titration data.

    Science.gov (United States)

    Papanastasiou, G; Ziogas, I

    1995-06-01

    New iterative methods for analysis of potentiometric titration data of (a) mixtures of weak monoprotic acids with their conjugate bases, (b) solutions of polyprotic (di- and triprotic) acids, and (c) mixtures of two diprotic acids are presented. These methods, using data exclusively resulting from the acidic region of the titration curve permits the accurate determination of the analytical concentration of one or more acids even if the titration is stopped well before the end point of the titration. For the titration of a solution containing a conjugate acid/base pair, the proposed procedure enables the extraction of the initial composition of the mixture, as well as the dissociation constant of the concerned acid. Thus, it is possible by this type of analysis to distinguish whether a weak acid has been contaminated by a strong base and define the extent of the contamination. On the other hand, for the titration of polyprotic acids, the proposed approach enables the extraction of the accurate values of the equivalence volume and the dissociation constants K(i) even when the ionization stages overlap. Finally, for the titration of a mixture of two diprotic acids the proposed procedure enables the determination of the composition of the mixture even if the sum of the concentrations of the acids is not known. This method can be used in the analysis of solutions containing two diastereoisomeric forms of a weak diprotic acid. The test of the proposed procedures by means of ideal and Monte Carlo simulated data revealed that these methods are fairly applicable even when the titration data are considerably obscured by 'noise' or contain an important systematic error. The proposed procedures were also successfully applied to experimental titration data.

  11. Simultaneous determination of piracetam and vincamine by spectrophotometric and high-performance liquid chromatographic methods.

    Science.gov (United States)

    El-Saharty, Yasser Shaker Ibrahim

    2008-01-01

    A mixture of piracetam and vincamine was determined by 3 different methods. The first was the determination of piracetam and vincamine using the ratio-spectra first-derivative (DD1) spectrophotometric technique at 209 and 293 nm in concentration ranges of 10-45 and 2-14 microg/mL with mean recoveries of 99.22 +/- 0.72 and 99.67 +/- 0.79%, respectively. The second method was based on the resolution of the 2 components by bivariate calibration depending on a mathematic algorithm that provides simplicity and rapidity. The method depended on quantitative evaluation of the absorbencies at 210 and 225 nm in concentration ranges of 5-45 and 2-14 microg/mL, with mean recoveries of 100.33 +/- 0.54 and 100.44 +/- 0.98% for piracetam and vincamine, respectively. The third method was reversed-phase liquid chromatography using 0.05 M potassium dihydrogen phosphate-methanol (50 + 50, v/v) as the mobile phase, with the pH adjusted to 3.5 with phosphoric acid. The eluent was monitored at 215 nm in concentration ranges of 5-100 and 2-200 microg/mL, with mean recoveries of 99.62 +/- 0.67 and 99.32 +/- 0.85% for piracetam and vincamine, respectively. The suggested procedures were checked using laboratory-prepared mixtures and were successfully applied for the analysis of their pharmaceutical preparation. The methods retained their accuracy and precision when applying the standard addition technique. The results obtained by applying the proposed methods were statistically analyzed and compared with those obtained by the manufacturer's method.

  12. Simultaneous determination of organophosphorous insecticides in bean samples by gas chromatography - flame photometric detection

    Directory of Open Access Journals (Sweden)

    Keyller Bastos Borges

    2014-02-01

    Full Text Available The indiscriminate use of organophosphorous pesticides (OPPs in crops may leave residues in food and may cause poisoning in the applicators. A method was developed for the determination of five OPPs in bean samples by Gas Chromatography-Flame Photometric Detection (GC-FPD. Validation parameters comprised linearity between 0.24 and 8.56 μg g-1 (r = 0.9985 for diazinon; 0.23 and 8.14 μg g-1 (r = 0.9959 for methyl parathion; 0.28 and 10.25 μg g-1 (r = 0.9987 for methyl pirimiphos; 0.52 and 18.87 μg g-1 (r = 0.9955 for malathion; 0.86 and 13.67 μg g-1 (r = 0.9919 for ethion. The limits of quantification (equal to those of detection were the lowest rates of ranges mentioned above for each compound. The extraction method showed approximately 95% recovery, with CV% < 15%. Although twenty-eight bean samples obtained in the southern region of the state of Minas Gerais,Brazil, were analyzed, they failed to match any of the OPPs under analysis. The absence of OPPs in the samples could be due to the degradation that occurred between the use of OPPs and bean commercialization, levels below the detection /quantification limits and the non-use of OPPs in bean cultivation.

  13. HPTLC method for simultaneous determination of piperine, embeline, and carvone in the ayurvedic formulation Catpusphadhya churna.

    Science.gov (United States)

    Jain, Kajal L; Patel, Rakesh K; Patel, Hardik P

    2014-01-01

    Churnas are an important group of formulations used by traditional physicians to treat various types of diseases. The principle of using a churna is based on the fact that the therapeutic value of most substances greatly increases when they are reduced to a very fine state of subdivision. Catpusphadhya churna, as per the Ayurvedic system of Indian medicine, is used for acute rheumatoid arthritis. In the present study, an attempt was made to develop an HPTLC method for the quantitative determination of piperine, embeline, and carvone in a laboratory-prepared formulation. Raw materials used in formulations were obtained from two different suppliers and were subjected to methanol extractions by using a Soxhlet apparatus. Piperine, embeline, and carvone were quantified in the extracts by using HPTLC. The detection and quantification were performed at 254 nm. The formulation contained 2.35% (w/w) of piperine, 4.86% (w/w) of embeline, and 1.48% (v/w) of carvone. Linearity studies indicated that piperine, embeline, and carvone were in the linear ranges, while the recovery studies revealed a recovery of 99.32% (w/w) of piperine, 101.82% (w/w) of embeline, and 100.09% (v/w) of carvone, thus proving the accuracy of the analysis. The developed HPTLC method resolved and quantified piperine, embeline, and carvone effectively, so it could be an important method for the QC of polyherbal formulations.

  14. Integrated disposable electrochemical immunosensors for the simultaneous determination of sulfonamide and tetracycline antibiotics residues in milk.

    Science.gov (United States)

    Conzuelo, Felipe; Campuzano, Susana; Gamella, María; Pinacho, Daniel G; Reviejo, A Julio; Marco, M Pilar; Pingarrón, José M

    2013-12-15

    The design, preparation and analytical performance of a novel integrated amperometric immunosensor based on the immobilization of selective capture antibodies on the surface of Protein G-modified screen-printed dual carbon electrodes (SPdCEs) for the multiplexed determination of sulfonamide and tetracycline antibiotics residues in milk is reported in this work. Protein G was covalently immobilized onto a 4-aminobenzoic acid (4-ABA) film grafted on the disposable electrode, and a direct competitive immunoassay using horseradish peroxidase (HRP)-labeled tracers was performed. The amperometric responses measured at -0.2 V vs. the silver pseudo-reference electrode of the SPdCE upon the addition of H2O2 in the presence of hydroquinone (HQ) as mediator were used to monitor the extent of the immunoreactions. The developed methodology showed very low limits of detection (in the low ppb level) for sulfonamide and tetracycline antibiotics tested in untreated milk samples, and a good selectivity against other antibiotic residues frequently detected in milk and dairy products. The usefulness of the dual immunosensor was demonstrated by analyzing spiked milk samples as well as a reference milk containing a certified oxytetracycline (OTC) content. Good recoveries were attained in an analysis time of 30 min. Copyright © 2013 Elsevier B.V. All rights reserved.

  15. Simultaneous determination of phenylethanoid glycosides and aglycones by capillary zone electrophoresis with running buffer modifier.

    Science.gov (United States)

    Dong, Shuqing; Gao, Ruibin; Yang, Yan; Guo, Mei; Ni, Jingman; Zhao, Liang

    2014-03-15

    Although the separation efficiency of capillary electrophoresis (CE) is much higher than that of other chromatographic methods, it is sometimes difficult to adequately separate the complex ingredients in biological samples. This article describes how one effective and simple way to develop the separation efficiency in CE is to add some modifiers to the running buffer. The suitable running buffer modifier β-cyclodextrin (β-CD) was explored to fast and completely separate four phenylethanoid glycosides and aglycones (homovanillyl alcohol, hydroxytyrosol, 3,4-dimethoxycinnamic acid, and caffeic acid) in Lamiophlomis rotata (Lr) and Cistanche by capillary zone electrophoresis with ultraviolet (UV) detection. It was found that when β-CD was used as running buffer modifier, a baseline separation of the four analytes could be accomplished in less than 20 min and the detection limits were as low as 10(-3) mg L(-1). Other factors affecting the CE separation, such as working potential, pH value and ionic strength of running buffer, separation voltage, and sample injection time, were investigated extensively. Under the optimal conditions, a successful practical application on the determination of Lr and Cistanche samples confirmed the validity and practicability of this method. Copyright © 2014 Elsevier Inc. All rights reserved.

  16. Simultaneous Analytical Techniques for Determination of 8 Synthetic Food Colors in Foods by HPLC

    Energy Technology Data Exchange (ETDEWEB)

    Park, S.K.; Lee, C.H.; Park, J.S.; Yoon, H.J.; Kim, S.H.; Hong, Y.; Lee, J.O.; Lee, C.W. [Korea Food and Drug Administration, Seoul (Korea)

    2000-06-01

    This Study has been carried out to develop a method of analysis of 8 permitted synthetic food colors [including Brilliant Blue FCF (B1), Indigocarmine (B2), Fast green FCF (G3), Amaranth (R2), Erythrosine (R3), Allura red (R40), Tartrazine (Y4), Sunset Yellow FCF (Y5)] in Korean foods by HPLC. After adjusting to 0.5% HCl, each of the food colors extracted was eluted by Sep-pak C{sub 18} cartridge. Eluates were then determined by high performance liquid chromatograph with a UV-VIS detector. Recoveries of the 8 synthetic food colors were found to be 81.2-98.0% for soft drinks, 80.6-96.1% for candy, 79.8-96.3% for chewing gum, 76.5-91.7% for cereals, 79.0-93.8% for ice cream and 78.6-94.7% for jelly, respectively. The detection limits were 0.05-0.1 {mu}g/g. (author). 24 refs., 2 tabs., 4 figs.

  17. Simultaneous determination of artificial sweeteners, preservatives, caffeine, theobromine and theophylline in food and pharmaceutical preparations by ion chromatography.

    Science.gov (United States)

    Chen, Q C; Wang, J

    2001-12-07

    A novel ion chromatographic method was proposed for the simultaneous determination of artificial sweeteners (sodium saccharin, aspartame, acesulfame-K), preservatives (benzoic acid, sorbic acid), caffeine, theobromine and theophylline. The separation was performed on an anion-exchange analytical column operated at 40 degrees C within 45 min by an isocratic elution with 5 mM aqueous NaH2PO4 (pH 8.20) solution containing 4% (v/v) acetonitrile as eluent, and the determination by wavelength-switching ultraviolet absorbance detection. The detection limits (signal-to-noise ratio 3:1) for all analytes were below the sub-microg/ml level. Under the experimental conditions, several organic acids, including citric acid, malic acid, tartaric acid and ascorbic acid, did not interfere with the determination. The method has been successfully applied to the analysis of various food and pharmaceutical preparations, and the average recoveries for real samples ranged from 85 to 104%. The levels of all analytes determined by this method were in good agreement with those obtained by the high-performance liquid chromatographic procedure. The results also indicated that ion chromatography would be possibly a beneficial alternative to conventional high-performance liquid chromatography for the separation and determination of these compounds.

  18. Simultaneous determination of acetylsalicylic and salicylic acids in human serum and aspirin formulations by second-derivative synchronous fluorescence spectrometry.

    Science.gov (United States)

    Konstantianos, D G; Ioannou, P C; Efstathiou, C E

    1991-04-01

    A second-derivative synchronous scanning spectrofluorimetric method for the simultaneous determination of acetylsalicylic acid (ASA) and salicylic acid (SA) is described. The method is based on the native fluorescence of both acids in a 1% acetic acid-chloroform solution. Both ASA and SA can be determined within the concentration ranges 0.2-70 and 0.03-10 micrograms ml-1, respectively. The effect of each acid on the signal of the other has been studied in detail. Empirical equations have been used to overcome this effect, thus allowing the accurate determination of both acids in binary mixtures, without a separation step. The method has been applied to the determination of ASA and SA in blood serum and to the determination of SA impurities in aspirin formulations. Recoveries from sera spiked with both ASA (2.5-50 micrograms ml-1) and SA (100-160 micrograms ml-1) varied from 99.5 to 106.7% (mean = 102.6%) and from 93.0 to 98.0% (mean = 95.8%), respectively. Recoveries of SA from spiked aspirin solutions (0.25-1.5 mg g-1 of aspirin) varied from 98.0 to 102.0% (mean = 100.3%).

  19. Portable High Sensitivity and High Resolution Sensor to Determine Oxygen Purity Levels, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — The objective of this Phase I STTR project is to develop a highly sensitive oxygen (O2) sensor, with high accuracy and precision, to determine purity levels of high...

  20. Fast and simultaneous determination of eleven synthetic color additives in flour and meat products by liquid chromatography coupled with diode-array detector and tandem mass spectrometry.

    Science.gov (United States)

    Qi, Ping; Lin, Zi-hao; Chen, Gui-yun; Xiao, Jian; Liang, Zhi-an; Luo, Li-ni; Zhou, Jun; Zhang, Xue-wu

    2015-08-15

    In this study, an efficient, fast and sensitive method for the simultaneous determination of eleven synthetic color additives (Allura red, Amaranth, Azo rubine, Brilliant blue, Erythrosine, Indigotine, Ponceau 4R, New red, Sunset yellow, Quinoline yellow and Tartrazine) in flour and meat foodstuffs is developed and validated using HPLC coupled with DAD and MS/MS. The color additives were extracted with ammonia-methanol and was further purified with SPE procedure using Strata-AW column in order to reduce matrix interference. This HPLC-DAD method is intended for a comprehensive survey of color additives in foods. HPLC-MS/MS method was used as the further confirmation and identification. Validation data showed the good recoveries in the range of 75.2-113.8%, with relative standard deviations less than 15%. These methods are suitable for the routine monitoring analysis of eleven synthetic color additives due to its sensitivity, reasonable time and cost. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. Simultaneous Determination of 13 Anticoagulant Rodenticidesin Human Blood by Liquid Chromatography-Tandem Mass Spectrometry and its Application in Three Poisoning Cases.

    Science.gov (United States)

    Qiao, Zheng; Xiang, Ping; Shen, Baohua; Shen, Min; Yan, Hui

    2018-05-01

    Anticoagulant rodenticides are widely used for rodent control around the world. A rapid and sensitive method was developed and validated for the simultaneous determination of 13 anticoagulant rodenticides (coumafuryl, pindone, valone, warfarin, coumatetralyl, coumachlor, diphacinone, dicumarol, chlorophacinone, bromadiolone, difenacoum, flocoumafen, and brodifacoum) in human blood by liquid chromatography-tandem mass spectrometry. After liquid-liquid extraction, the anticoagulant rodenticides were separated on an Eclipse Plus C18 column. Linearities were observed for each analyte in blood ranging from 0.5 to 50 ng/mL, with correlation coefficients over 0.99. The limits of detection ranged from 0.01 to 0.2 ng/mL, and the limits of quantification were 0.5 ng/mL for all analytes. The intraday and interday precisions were <15%, and accuracies ranged from 80.3% to 111.0%. This validated method with high sensitivity has been applied in three anticoagulant rodenticide poisoning cases and has been used successfully in monitoring blood concentrations for months. © 2017 American Academy of Forensic Sciences.

  2. Simultaneous determination of oleanolic acid, ursolic acid, quercetin and apigenin in Swertia mussotii Franch by capillary zone electrophoresis with running buffer modifier.

    Science.gov (United States)

    Gao, Ruibin; Wang, Litao; Yang, Yan; Ni, Jingman; Zhao, Liang; Dong, Shuqing; Guo, Mei

    2015-03-01

    The method of capillary zone electrophoresis (CZE) with direct UV detection was developed for the determination of oleanolic acid, ursolic acid, quercetin and apigenin. and then for the first time successfully applied to the analysis of four analytes in Swertia mussotii Franch and its preparations. Various factors affecting the CZE procedure were investigated and optimized, and the optimal conditions were: 50 × 10(-3) mol/L borate-phosphate buffer (pH 9.5) with 5.0 × 10(-3) mol/L β-cyclodextrin, 15 kV separation voltage, 20 °C column temperature, 250 nm detection wavelength and 5 s electrokinetic injection time (voltage 20 psi). Under the conditions, oleanolic acid, ursolic acid, quercetin and apigenin could be determined within the test ranges with a good correlation coefficient (r(2) > 0.9991). The limits of detection for conditions, oleanolic acid, ursolic acid, quercetin and apigenin were 0.3415, 0.2003, 0.0062 and 0.2538 µg/mL, respectively, and the intra- and inter-day relative standard deviations were no more than 4.72%. This procedure provided a convenient, sensitive and accurate method for simultaneous determination of oleanolic acid, ursolic acid, quercetin and apigenin in S. mussotii Franch. Copyright © 2014 John Wiley & Sons, Ltd.

  3. Simultaneous Determination of Parathion, Malathion, Diazinon, and Pirimiphos Methyl in Dried Medicinal Plants Using Solid-Phase Microextraction Fibre Coated with Single-Walled Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    Reza Ahmadkhaniha

    2012-01-01

    Full Text Available A reliable and sensitive headspace solid-phase microextraction gas chromatography-mass spectrometry method for simultaneous determination of different organophosphorus pesticides in dried medicinal plant samples is described. The analytes were extracted by single-walled carbon nanotubes as a new solid-phase microextraction adsorbent. The developed method showed good performance. For diazinon and pirimiphos methyl calibration, curves were linear (r2≥0.993 over the concentration ranges from 1.5 to 300 ng g−1, and the limit of detection at signal-to-noise ratio of 3 was 0.3 ng g−1. For parathion and malathion, the linear range and limit of detection were 2.5–300 (r2≥0.991 and 0.5 ng g−1, respectively. In addition, a comparative study between the single-walled carbon nanotubes and a commercial polydimethylsiloxane fibre for the determination of target analytes was carried out. Single-walled carbon nanotubes fibre showed higher extraction capacity, better thermal stability (over 350∘C, and longer lifespan (over 250 times than the commercial polydimethylsiloxane fibre. The developed method was successfully applied to determine target organophosphorus pesticides in real samples.

  4. Simultaneous determination of household and market-oriented activities of women in rural Pakistan.

    Science.gov (United States)

    Alderman, H; Chishti, S

    1991-01-01

    Researchers applied data from the 1985-1986 Labour Force Survey in Pakistan to a model which focused on household composition variables and human assets such as education to examine determinants of female labor force participation in the framework of their labor on other productive tasks in the household in rural areas. Monthly household labor decreased by 1.8 days for each additional adult woman in the household and by 1.4 days for each 10-15 year old girl. On the other hand, an extra teenage boy added as much to each woman's workload as did an additional 5-9 year old child (.37 days). Each additional 6 year old child increased the workload 1.3 days/month and this did not include child care activities. Women who had attended primary school worked in the household 1.4 days less than those who did not attend any school. Moreover those who attended school beyond primary school worked in the household 3.7 days less than those who did not attend any school. both of these differences were statistically significant. Yet educated women worked more outside the house than uneducated women (1.2 days for those with primary education and 2.4 days for those with post primary education). The government should promote increased female school participation by increasing its investment in schooling to lower the costs to households. Further it could provide opportunities for educated women to be employed in their own communities. Thus they can envision education in their private interest (both in social and financial terms). If these efforts are not done, however, demand and supply considerations may continue to restrain schooling for females.

  5. Stability-indicating RP-HPLC method for the simultaneous determination of escitalopram oxalate and clonazepam.

    Science.gov (United States)

    Kakde, Rajendra B; Satone, Dinesh D; Gadapayale, Kamalesh K; Kakde, Megha G

    2013-07-01

    The objective of the current study was to develop a validated, specific stability-indicating reversed-phase liquid chromatographic (LC) method for the quantitative determination of escitalopram oxalate and clonazepam and their related substances in bulk drugs and pharmaceutical dosage forms in the presence of degradation products. Forced degradation studies were performed on the pure drugs of escitalopram oxalate and clonazepam, as per the stress conditions prescribed by the International Conference on Harmonization (ICH) using acid, base, oxidation, thermal stress and photolytic degradation to show the stability-indicating power of the method. Significant degradation was observed during acid and alkaline hydrolysis and no degradation was observed in other stress conditions. The chromatographic method was optimized using the samples generated from forced degradation studies. Good resolution between the peaks corresponded to the active pharmaceutical ingredients, escitalopram oxalate and clonazepam, and degradation products from the analyte were achieved on an ODS Hypersil C18 column (250 × 4.6 mm) using a mobile phase consisting of a mixture of acetonitrile-50 mM phosphate buffer + 10 mM triethylamine (70:30, v/v). The detection was conducted at 268 nm. The limit of detection and the limit of quantitation for escitalopram oxalate and clonazepam were established. The stress test solutions were assayed against the qualified working standards of escitalopram oxalate and clonazepam, which indicated that the developed LC method was stability-indicating. Validation of the developed LC method was conducted as per ICH requirements. The developed LC method was found to be suitable to check the quality of bulk samples of escitalopram oxalate and clonazepam.

  6. Simultaneous determination of selenium and tellurium in native sulfur by atomic absorption spectrophotometry

    International Nuclear Information System (INIS)

    Arikawa, Yoshiko; Hirai, Shoji; Ozawa, Takejiro.

    1979-01-01

    A method for the determination of selenium and tellurium in native sulfur has been investigated by means of atomic absorption spectrophotometry. Native sulfur collected from around fumarole or volcanic crater is ground down into powder, a portion of which weighing 1 g is subjected to analysis. A 2.6% (w/v) sodium hydroxide solution is added by 10 ml to the sample in a teflon beaker, and the mixture is then heated on a hot plate. Sulfur is decomposed and dissolved in the form of disulfide and thiosulfate. A 30% hydrogenperoxide solution is added by 10 ml to oxidize them to sulfate. At the same time selenium and tellurium contained in the sulfur sample are also thought to be oxidized to Se(VI) and Te(VI) states. The solution is neutralized with hydrochloric acid and diluted with distilled water to 100 ml. The sample solution thus prepared is sprayed into the air-acetylene flame of the atomic absorption spectrophotometer. The absorbance is measured at 195.9 nm for selenium and 214.2 nm for tellurium. Calibration curve is prepared by measuring the absorbances of the solutions prepared as follows. One gram portions of pure sulfur (99.9999%) are decomposed as for the samples. After neutralization, standard solutions containing each same amount of selenium and tellurium (0 -- 1000 μg) are added to the sulfur solution and then diluted with water to 100 ml. The standard deviations were estimated to be 50.4 ppm for selenium at 756 ppm and 16.6 ppm for tellurium at 587 ppm. For the check of the reliability of the method, results were compared with those obtained by neutron activation analysis. Results obtained by both methods showed good agreement. (author)

  7. Simultaneous determination of silver and other heavy metals in aquatic environment receiving wastewater from industrial area, applying an enrichment method

    Directory of Open Access Journals (Sweden)

    Naeemullah

    2016-01-01

    Full Text Available In the present study, silver (Ag, cadmium (Cd, nickel (Ni, cobalt (Co and lead (Pb were simultaneously determined in water samples of fresh water canal receiving untreated effluents from an industrial area, of Sindh Pakistan. The analytes in the water sample were determined by CPE using ammonium pyrrolidinedithiocarbamate (APDC as a complexing agent and then entrapped in non-ionic surfactant, octylphenoxypolyethoxyethanol (Triton X-114. The surfactant rich phase was diluted with acidic ethanol prior to analysis by flame atomic absorption spectrometry. The variables affecting the complexation and extraction steps such as pH of sample solution, concentration of oxine and Triton X-114, equilibration temperature and time period for shaking were investigated in detail. The validation of the procedure was carried out by analysis of a certified reference sample of water (CRM1634e. Reliability of the proposed method was also checked by the standard addition method in a real sample at three concentration levels of all metals. Under the optimum conditions, the preconcentration of 10 mL sample solutions, allowed preconcentration factor of 20-fold. The lower limit of detection obtained for Ag, Cd, Ni, Co and Pb was 0.42, 0.48, 0.92, 0.62, and 1.42 μg L−1, respectively. The proposed procedure was successfully applied to waste and fresh water samples for simultaneous determination of different metals. The concentration of Ag, Cd, Ni, Co and Pb has shown a decreased trend from 46.5–6.96, 23.0–8.92, 30.2–12.8, 14.2–4.45 and 15.3–5.32 μg L−1, respectively from initial entrance of waste water along the downstream of canal.

  8. Simultaneous determination of free and total glycerol in biodiesel by capillary electrophoresis using multiple short-end injection.

    Science.gov (United States)

    Spudeit, Daniel Alfonso; Piovezan, Marcel; Dolzan, Maressa D; Vistuba, Jacqueline Pereira; Azevedo, Mônia Stremel; Vitali, Luciano; Leal Oliveira, Marcone Augusto; Oliveira Costa, Ana Carolina; Micke, Gustavo Amadeu

    2013-12-01

    A rapid method for the simultaneous determination of free glycerol (FG) and total glycerol (TG) in biodiesel by CE using a short-end multiple injection (SE/MI) configuration system is described. The sample preparation for FG involves the extraction of glycerol with water and for TG a saponification reaction is carried out followed by extraction as in the case of FG. The glycerol extracted in both cases is submitted to periodate oxidation and the iodate ions formed are measured on a CE-SE/MI system. The relevance of this study lies in the fact that no analytical procedure has been previously reported for the determination of TG (or of FG and TG simultaneously) by CE. The optimum conditions for the saponification/extraction process were 1.25% KOH and 25°C, with a time of only 5 min, and biodiesel mass in the range of 50.0-200.0 mg can be used. Multiple injections were performed hydrodynamically with negative pressure as follows: 50 mbar/3s (FG sample); 50 mbar/6s (electrolyte spacer); 50 mbar/3s (TG sample). The linear range obtained was 1.55-46.5 mg/L with R(2) > 0.99. The LOD and LOQ were 0.16 mg/L and 0.47 mg/L, respectively for TG. The method provides acceptable throughput for application in quality control and monitoring biodiesel synthesis process. In addition, it offers simple sample preparation (saponification process), it can be applied to a variety biodiesel samples (soybean, castor, and waste cooking oils) and it can be used for the determination of two key parameters related to the biodiesel quality with a fast separation (less than 30 s) using an optimized CE-SE/MI system. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Simultaneous determination of piracetam and its four impurities by RP-HPLC with UV detection.

    Science.gov (United States)

    Arayne, M Saeed; Sultana, Najma; Siddiqui, Farhan Ahmed; Mirza, Agha Zeeshan; Qureshi, Faiza; Zuberi, M Hashim

    2010-08-01

    A simple and rapid high-performance liquid chromatographic method for the separation and determination of piracetam and its four impurities, 2-oxopyrrolidin-1-yl)acetic acid, pyrrolidin-2-one, methyl (2-oxopyrrolidin-1-yl)acetate, and ethyl (2-oxopyrrolidin-1-yl)acetate, was developed. The separation was achieved on a reversed-phase C(18) Nucleosil column (25 cm x 0.46 cm, 10 microm). The mobile phase is composed of an aqueous solution containing 0.2 g/L of triethyl amine-acetonitrile (85:15, v/v). The pH of the mobile phase was adjusted to 6.5 with phosphoric acid at a flow rate of 1 mL/min at ambient temperature and UV detection at 205 nm. The developed method was found to give good separation between the pure drug and its four related substance. The polynomial regression data for the calibration plots showed good linear relationship in the concentration range of 50-10,000 ng/mL, 25-10,000 ng/mL, 45-10,000 ng/mL, 34-10,000 ng/mL, and 55-10,000 ng/mL, respectively, with r(2) = 0.9999. The method was validated for precision, accuracy, ruggedness, and recovery. The minimum quantifiable amounts were found to be 50 ng/mL of piracetam, 25 ng/mL of 2-oxopyrrolidin-1-yl)acetic acid, 45 ng/mL of pyrrolidin-2-one, 34 ng/mL of methyl (2-oxopyrrolidin-1-yl)acetate, and 55 ng/mL of ethyl (2-oxopyrrolidin-1-yl)acetate. Statistical analysis proves that the method is reproducible and selective for the estimation of piracetam as well as its related substance. As the method could effectively separate the drug from the related substances, it can be employed as a stability-indicating one. The proposed method shows high efficiency, allowing the separation of the main component piracetam from other impurities.

  10. Effect of Body Position on Energy Expenditure of Preterm Infants as Determined by Simultaneous Direct and Indirect Calorimetry.

    Science.gov (United States)

    Bell, Edward F; Johnson, Karen J; Dove, Edwin L

    2017-04-01

    Background  Indirect calorimetry is the standard method for estimating energy expenditure in clinical research. Few studies have evaluated indirect calorimetry in infants by comparing it with simultaneous direct calorimetry. Our purpose was (1) to compare the energy expenditure of preterm infants determined by these two methods, direct calorimetry and indirect calorimetry; and (2) to examine the effect of body position, supine or prone, on energy expenditure. Study Design  We measured energy expenditure by simultaneous direct (heat loss by gradient-layer calorimeter corrected for heat storage) and indirect calorimetry (whole-body oxygen consumption and carbon dioxide production) in 15 growing preterm infants during two consecutive interfeeding intervals, once in the supine position and once in the prone position. Results  The mean energy expenditure for all measurements in both positions did not differ significantly by the method used: 2.82 (standard deviation [SD] 0.42) kcal/kg/h by direct calorimetry and 2.78 (SD 0.48) kcal/kg/h by indirect calorimetry. The energy expenditure was significantly lower, by 10%, in the prone than in the supine position, whether examined by direct calorimetry (2.67 vs. 2.97 kcal/kg/h, p  position than in the supine position. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

  11. Simultaneous determination of tetrahydrocortisol, allotetrahydrocortisol and tetrahydrocortisone in human urine by liquid chromatography-electrospray ionization tandem mass spectrometry.

    Science.gov (United States)

    Yamashita, Kouwa; Nakagawa, Risa; Okuyama, Mitsunobu; Honma, Seijiro; Takahashi, Madoka; Numazawa, Mitsuteru

    2008-08-01

    Simultaneous quantification method of three major metabolites of cortisone and cortisol, tetrahydrocortisol, allotetrahydrocortisol and tetrahydrocortisone by liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) was investigated in a positive mode using a recently developed picolinyl derivatization. Conversion of each steroid into the corresponding picolinyl derivatives (1b, 2b or 3b) was performed by mixed anhydride method using picolinic acids and 2-methyl-6-nitrobenzoic anhydride. Derivatization proceeded smoothly to afford the corresponding 3, 21-dipicolinyl derivatives. Positive ion-ESI mass spectra of the picolinyl derivatives were dominated by an appearance of [M+H](+) as base peaks in all cases. The picolinyl derivatives provided 15 to 80-fold higher ESI response in the LC-ESI-MS/MS (selected reaction monitoring: SRM) when compared to those of underivatized molecules in a positive LC-ESI mode. The use of the picolinyl ester, solid-phase extraction, and deuterium labeled internal standards enabled the concentrations of these metabolites in human urine to be determined simultaneously by LC-ESI-MS/MS (SRM) with a small sample volume of less than 1microl urine.

  12. [Simultaneous Determination of Sn and S in Methyltin Mercaptide by Microwave-Assisted Acid Digestion and ICP-OES].

    Science.gov (United States)

    Chen, Qian; Wu, Xi; Hou, Xian-deng; Xu, Kai-lai

    2015-09-01

    Methyltin mercaptide is widely used as one of the best heat stabilizer in the polyvinylchloride (PVC) thermal processing due to its excellent stability, good transparency, high compatibility and weather resistance. The content of sulfur and tin significantly affects its quality and performance, so it is of great significance to develop an analytical method for the simultaneous determination of sulfur and tin. Inductively coupled plasma atomic emission spectrometry (ICP-OES) has been a powerful analytical tool for a myriad of complex samples owing to its advantages of the low detection limits, rapid and precise determinations over wide dynamic ranges, freedom from chemical inter-element interferences, the high sample throughput and above all, simultaneous multi-elements analysis. Microwave technique as a well-developed method for sample preparation can dramatically reduce the digestion time and the loss of volatile elements compared with the traditional open digestion. Hereby, a microwave-assisted acid digestion (MW-AAD) procedure followed by inductively coupled plasma optical emission spectroscopy (ICP-OES) analysis was developed for the simultaneous determination of Sn and S in methyltin mercaptide. This method has the advantages of simplicity, rapidness, good accuracy, green and less use of samples. Parameters affecting the MW-AAD such as the digestion solution and digestion time were optimized by using a chemical analyzed reference sample (DX-181) to attain tin and sulfur quantitative recoveries. HNO3-HCl-HClO4 (v/v/v=9:3:1) and 10 min were the optimum digestion solution and digestion time, respectively. Under optimum conditions, the standard addition method and the standard calibration curve method were both been used to detect Sn and S in DX-181. There was no significant difference between two methods and the relative deviations to the chemical analysis values were both less than 2%. Additionally, the accuracy of the MW-AAD method was examined by analyzing

  13. Simultaneous Determination of Acetaminophen and Synthetic Color(s) by Derivative Spectroscopy in Syrup Formulations and Validation by HPLC: Exposure Risk of Colors to Children.

    Science.gov (United States)

    Rastogi, Shanya Das; Dixit, Sumita; Tripathi, Anurag; Das, Mukul

    2015-06-01

    Color additives are used in pediatric syrup formulations as an excipient; though not pre-requisite, but pediatric syrup formulations are normally colored. An attempt has been made to measure simultaneously the single drug, acetaminophen (AT), along with the colors, carmoisine (CA), erythrosine (ET), and sunset yellow FCF (SSY) added in it by three derivative spectroscopy methods namely, 1st order, ratio, and differential derivative methods. Moreover, evaluation has been made for the exposure assessment of the colors added as excipient because some colors have been reported to cause allergic reactions and hypersensitivity in children. The present methods provide simple, accurate, and reproducible quantitative determination of the drug, AT, along with the color in synthetic mixtures and commercial drug formulations without any interference. The limit of detection varied from 0.0001-0.31 μg/ml while limit of quantification ranged from 0.002-1.04 μg/ml in all the three methods. The calibration curve of all the three derivative methods exhibited good linear relationship with excellent regression coefficients (0.9986-1.000). Both intra-day and inter-day precisions showed %RSD value less than 2% while the percentage recovery was found between 96.8-103.8%. The sensitivity of the proposed methods is almost comparable to HPLC and thus, can be used for determination of drug AT, and color simultaneously in pharmaceutical formulation on routine basis. The present methods also showed that colors like SSY and ET are saturating more than 50% of acceptable daily intake (ADI) value which is alarming and needs to be considered for modification by regulatory authorities to safeguard the health of children.

  14. Simultaneous determination of neonicotinoid insecticides in human serum and urine using diatomaceous earth-assisted extraction and liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Yamamuro, Tadashi; Ohta, Hikoto; Aoyama, Mika; Watanabe, Daisuke

    2014-10-15

    A rapid and sensitive analytical method was developed for simultaneous determination of eight neonicotinoid insecticides (acetamiprid, clothianidin, dinotefuran, flonicamid, imidacloprid, nitenpyram, thiacloprid and thiamethoxam) and three specific metabolites of acetamiprid (N-desmethylacetamiprid, 5-(N-acetyl-N-methylaminomethyl)-2-chloropyridine and 5-(N-acetylaminomethyl)-2-chloropyridine) in human serum and urine. A diatomaceous earth-assisted extraction using Extrelut NT3 column with chloroform/2-propanol (3:1, v/v) as eluent was selected for the single step cleanup procedure for all the target compounds. Qualitative and quantitative analyses were conducted by liquid chromatography-tandem mass spectrometry with multiple reaction monitoring mode. The limits of detection and the limits of quantification of eleven compounds were in the ranges of 0.1-0.2ng/mL and 0.5-10ng/mL for serum, 0.1-1ng/mL and 1-10ng/mL for urine, respectively. The extraction recoveries were between 80.9% and 101.8% for serum samples, 91.9% and 106% for urine samples. The intra-day RSDs and the inter-day RSDs were less than 11.5% and 13.2% for serum, less than 8.3% and 8.8% for urine. The proposed procedure will be suitable for forensic investigations of human poisoning cases with neonicotinoid insecticides. This is the first report of simultaneous determination of eight neonicotinoids in serum and urine samples. Copyright © 2014. Published by Elsevier B.V.

  15. Reconstruction from limited single-particle diffraction data via simultaneous determination of state, orientation, intensity, and phase.

    Science.gov (United States)

    Donatelli, Jeffrey J; Sethian, James A; Zwart, Peter H

    2017-07-11

    Free-electron lasers now have the ability to collect X-ray diffraction patterns from individual molecules; however, each sample is delivered at unknown orientation and may be in one of several conformational states, each with a different molecular structure. Hit rates are often low, typically around 0.1%, limiting the number of useful images that can be collected. Determining accurate structural information requires classifying and orienting each image, accurately assembling them into a 3D diffraction intensity function, and determining missing phase information. Additionally, single particles typically scatter very few photons, leading to high image noise levels. We develop a multitiered iterative phasing algorithm to reconstruct structural information from single-particle diffraction data by simultaneously determining the states, orientations, intensities, phases, and underlying structure in a single iterative procedure. We leverage real-space constraints on the structure to help guide optimization and reconstruct underlying structure from very few images with excellent global convergence properties. We show that this approach can determine structural resolution beyond what is suggested by standard Shannon sampling arguments for ideal images and is also robust to noise.

  16. Simultaneous Determination of Ibuprofen and Caffeine in Urine Samples by Combining MCR-ALS and Excitation-emission Data

    Directory of Open Access Journals (Sweden)

    Masoumeh Mohammadnejad

    2016-06-01

    Full Text Available Second order advantage of excitation-emission fluorescence matrix was applied for the simultaneous determination of ibuprofen and caffeine. The proposed method is based on the measurement of the native fluorescence and recording emission spectra of ibuprofen and caffeine in different excitation wavelengths. The mixture of these compounds was resolved by multivariate curve resolution coupled with alternative least squares (MCR-ALS on constructed matrix. The EEM spectra were recorded at excitation wavelengths from 250-275 nm; the emission wavelengths ranged from 275-400 nm. For each particular quantitative determination, an augmented matrix was defined. The resolution of each augmented-data matrix gave an estimation of the excitation and emission spectra of the species included in the model. Ibuprofen and caffeine were determined in concentration range from 0.10-8.00 and 0.50-15.00 mg ml-1, respectively. The minimal sample pretreatment and relatively low running cost, make this method a good alternative to existing methods for determination of the analytes in urine samples.

  17. Rapid, highly sensitive and highly specific gene detection by combining enzymatic amplification and DNA chip detection simultaneously

    Directory of Open Access Journals (Sweden)

    Koji Hashimoto

    2016-05-01

    Full Text Available We have developed a novel gene detection method based on the loop-mediated isothermal amplification (LAMP reaction and the DNA dissociation reaction on the same DNA chip surface to achieve a lower detection limit, broader dynamic range and faster detection time than are attainable with a conventional DNA chip. Both FAM- and thiol-labeled DNA probe bound to the complementary sequence accompanying Dabcyl was immobilized on the gold surface via Au/thiol bond. The LAMP reaction was carried out on the DNA probe fixed gold surface. At first, Dabcyl molecules quenched the FAM fluorescence. According to the LAMP reaction, the complementary sequence with Dabcyl was competitively reacted with the amplified targeted sequence. As a result, the FAM fluorescence increased owing to dissociation of the complementary sequence from the DNA probe. The simultaneous reaction of LAMP and DNA chip detection was achieved, and 103 copies of the targeted gene were detected within an hour by measuring fluorescence intensity of the DNA probe. Keywords: Biosensor, DNA chip, Loop-mediated isothermal amplification (LAMP, Fluorescence detection, Gold substrate, Au/thiol bond

  18. Highly sensitive determination of atropine using cobalt oxide nanostructures: Influence of functional groups on the signal sensitivity

    Energy Technology Data Exchange (ETDEWEB)

    Soomro, Razium Ali, E-mail: raziumsoomro@gmail.com [Interface Analysis Centre, School of Physics, University of Bristol, Bristol, BS8 1TL (United Kingdom); National Centre of Excellence in Analytical Chemistry, University of Sindh, Jamshoro, 76080 (Pakistan); Nafady, Ayman [Department of Chemistry, College of Science, King Saud University, Riyadh (Saudi Arabia); Department of Chemistry, Faculty of Science, Sohag University, Sohag (Egypt); Hallam, Keith Richard [Interface Analysis Centre, School of Physics, University of Bristol, Bristol, BS8 1TL (United Kingdom); Jawaid, Sana [National Centre of Excellence in Analytical Chemistry, University of Sindh, Jamshoro, 76080 (Pakistan); Al Enizi, Abdullah [Department of Chemistry, College of Science, King Saud University, Riyadh (Saudi Arabia); Sherazi, Syed Tufail Hussain; Sirajuddin [National Centre of Excellence in Analytical Chemistry, University of Sindh, Jamshoro, 76080 (Pakistan); Ibupoto, Zafar Hussain [Dr M.A. Kazi Institute of Chemistry, University of Sindh, Jamshoro, 76080 (Pakistan); Willander, Magnus [Department of Science and Technology, Campus Norrkoping, Linkoping University, SE-60174, Norrkoping (Sweden)

    2016-12-15

    This study describes sensitive determination of atropine using glassy carbon electrodes (GCE) modified with Co{sub 3}O{sub 4} nanostructures. The as-synthesised nanostructures were grown using cysteine (CYS), glutathione (GSH) and histidine (HYS) as effective templates under hydrothermal action. The obtained morphologies revealed interesting structural features, including both cavity-based and flower-shaped structures. The as-synthesised morphologies were noted to actively participate in electro-catalysis of atropine (AT) drug where GSH-assisted structures exhibited the best signal response in terms of current density and over-potential value. The study also discusses the influence of functional groups on the signal sensitivity of atropine electro-oxidation. The functionalisation was carried with the amino acids originally used as effective templates for the growth of Co{sub 3}O{sub 4} nanostructures. The highest increment was obtained when GSH was used as the surface functionalising agent. The GSH-functionalised Co{sub 3}O{sub 4}-modified electrode was utilised for the electro-chemical sensing of AT in a concentration range of 0.01–0.46 μM. The developed sensor exhibited excellent working linearity (R{sup 2} = 0.999) and signal sensitivity up to 0.001 μM of AT. The noted high sensitivity of the sensor is associated with the synergy of superb surface architectures and favourable interaction facilitating the electron transfer kinetics for the electro-catalytic oxidation of AT. Significantly, the developed sensor demonstrated excellent working capability when used for AT detection in human urine samples with strong anti-interference potential against common co-existing species, such as glucose, fructose, cysteine, uric acid, dopamine and ascorbic acid. - Highlights: • Template-assisted growth of Co{sub 3}O{sub 4} nanostructures. • Shape-dependent electro-catalysis of atropine. • Effect of functionalisation of signal sensitivity.

  19. Sequential injection approach for simultaneous determination of ultratrace plutonium and neptunium in urine with accelerator mass spectrometry

    DEFF Research Database (Denmark)

    Qiao, Jixin; Hou, Xiaolin; Roos, Per

    2013-01-01

    . Several experimental parameters affecting the analytical performance were investigated and compared including sample preboiling operation, aging time, amount of coprecipitating reagent, reagent for pH adjustment, sedimentation time, and organic matter decomposition approach. The overall analytical results...... show that preboiling and aging are important for obtaining high chemical yields for both Pu and Np, which is possibly related to the aggregation and adsorption behavior of organic substances contained in urine. Although the optimal condition for Np and Pu simultaneous determination requires 5-day aging...... time, an immediate coprecipitation without preboiling and aging could also provide fairly satisfactory chemical yields for both Np and Pu (50-60%) with high sample throughput (4 h/sample). Within the developed method, (242)Pu was exploited as chemical yield tracer for both Pu and Np isotopes. (242)Pu...

  20. Micellar HPLC and derivative spectrophotometric methods for the simultaneous determination of fluconazole and tinidazole in pharmaceuticals and biological fluids.

    Science.gov (United States)

    Belal, F; Sharaf El-Din, M K; Eid, M I; El-Gamal, R M

    2014-04-01

    Micellar high-performance liquid chromatography (HPLC) and first-derivative ultraviolet spectrophotometry were used to simultaneously determine fluconazole (FLZ) and tinidazole (TNZ) in combined pharmaceutical dosage forms. The derivative procedure is based on the linear relationship between the drug concentration and the first derivative amplitudes at 220 and 288 nm for FLZ and TNZ, respectively. The calibration graphs were linear in the range of 1.5-9.0 µg/mL for FLZ and 10.0-60.0 µg/mL for TNZ. Furthermore, an HPLC procedure with ultraviolet detection at 210 nm was developed. For the HPLC procedure, good chromatographic separation was achieved using an ODS C18 column (250 × 4.6 mm i.d.). The mobile phase containing 0.15M sodium dodecyl sulphate, 0.3% triethylamine and 12% n-propanol in 0.02M orthophosphoric acid at pH 5.5 was pumped at a flow rate of 1 mL/min. Indapamide was used as an internal standard. The method showed good linearity over the concentration ranges of 1.5-30.0 and 10.0-200.0 µg/mL, with limits of detection of 0.36 and 2.70 µg/mL and limits of quantification of 1.1 and 8.2 µg/mL for FLZ and TNZ, respectively. The suggested methods were successfully applied for the simultaneous analysis of the drugs in their laboratory prepared mixture, co-formulated tablet and single dosage forms. Moreover the second method was also extended to the determination of the drugs in biological fluids.

  1. Simultaneous electroanalytical determination of hydroquinone and catechol in the presence of resorcinol at an SiO2/C electrode spin-coated with a thin film of Nb2O5.

    Science.gov (United States)

    Canevari, Thiago C; Arenas, Leliz T; Landers, Richard; Custodio, Rogério; Gushikem, Yoshitaka

    2013-01-07

    This paper describes the development, characterization and application of an Nb(2)O(5) film formed on the surface of a carbon ceramic material, SiO(2)/C, obtained by a sol-gel method, using the spin-coating technique. The working electrode using this material will be designated as SiCNb. Hydroquinone and catechol can be oxidized at this electrode in the presence of resorcinol, allowing their simultaneous detection. The electrochemical properties of the resulting electrode were investigated using cyclic and differential pulse voltammetry techniques. Well-defined and separated oxidation peaks were observed by differential pulse voltammetry in Tris-HCl buffer solution at pH 7 containing 1 mol L(-1) KCl in the supporting electrolyte solution. The SiCNb electrode exhibited high sensitivity in the simultaneous determination of hydroquinone and catechol in the presence of resorcinol, with the limits of detection for hydroquinone and catechol being 1.6 μmol L(-1) and 0.8 μmol L(-1), respectively. Theoretical calculations were performed to determine the ionization energies of hydroquinone, catechol and resorcinol; the results were used to explain the simultaneous determination of species by differential pulse voltammetry. The presence of resorcinol did not produce any interference in the simultaneous detection of hydroquinone and catechol on the surface of the modified electrode.

  2. All-optical simultaneous multichannel quadrature phase shift keying signal regeneration based on phase-sensitive amplification

    Science.gov (United States)

    Wang, Hongxiang; Wang, Qi; Bai, Lin; Ji, Yuefeng

    2018-01-01

    A scheme is proposed to realize the all-optical phase regeneration of four-channel quadrature phase shift keying (QPSK) signal based on phase-sensitive amplification. By utilizing conjugate pump and common pump in a highly nonlinear optical fiber, degenerate four-wave mixing process is observed, and QPSK signals are regenerated. The number of waves is reduced to decrease the cross talk caused by undesired nonlinear interaction during the coherent superposition process. In addition, to avoid the effect of overlapping frequency, frequency spans between pumps and signals are set to be nonintegral multiples. Optical signal-to-noise ratio improvement is validated by bit error rate measurements. Compared with single-channel regeneration, multichannel regeneration brings 0.4-dB OSNR penalty when the value of BER is 10-3, which shows the cross talk in regeneration process is negligible.

  3. Multifunctional pH-sensitive magnetic nanoparticles for simultaneous imaging, sensing and targeted intracellular anticancer drug delivery

    International Nuclear Information System (INIS)

    Banerjee, Shashwat S; Chen, D-H

    2008-01-01

    A novel multifunctional magnetic nanocarrier was fabricated for synchronous cancer therapy and sensing. The nanocarrier, programed to display a response to environmental stimuli (pH value), was synthesized by coupling doxorubicin (DOX) to adipic dihydrazide-grafted gum arabic modified magnetic nanoparticles (ADH-GAMNP) via the hydrolytically degradable pH-sensitive hydrazone bond. The resultant nanocarrier, DOX-ADH-GAMNP, had a mean diameter of 13.8 nm and the amount of DOX coupled was about 6.52 mg g -1 . Also, it exhibited pH triggered release of DOX in an acidic environment (pH 5.0) but was relatively stable at physiological pH (pH 7.4). Furthermore, both GAMNP and DOX were found to possess fluorescence properties when excited in the near-infrared region due to the two-photon absorption mechanism. The coupling of DOX to GAMNP resulted in a reversible self-quenching of fluorescence through the fluorescence resonant energy transfer (FRET) between the donor GAMNP and acceptor DOX. The release of DOX from DOX-ADH-GAMNP when exposed to acidic media indicated the recovery of fluorescence from both GAMNP and DOX. The change in the fluorescence intensity of DOX-ADH-GAMNP on the release of DOX can act as a potential sensor to sense the delivery of the drug. The analysis of zeta potential and plasmon absorbance in different pH conditions also confirmed the pH sensitivity of the product. This multifunctional nanocarrier is a significant breakthrough in developing a drug delivery vehicle that combines drug targeting as well as sensing and therapy at the same time.

  4. Simultaneous determination of arterial input function of the internal carotid and middle cerebral arteries for dynamic susceptibility contrast MRI

    International Nuclear Information System (INIS)

    Scholdei, R.; Wenz, F.; Fuss, M.; Essig, M.; Knopp, M.V.

    1999-01-01

    Purpose: The determination of the arterial input function (AIF) is necessary for absolute quantification of the regional cerebral blood volume and blood flow using dynamic susceptibility contrast MRI. The suitability of different vessels (ICA-internal carotid artery, MCA-middle cerebral artery) for AIF determination was compared in this study. Methods: A standard 1.5 T MR system and a simultaneous dual FLASH sequence (TR/TE1/TE2/α=32/15/25/10 ) were used to follow a bolus of contrast agent. Slice I was chosen to cut the ICA perpendicularly. Slice II included the MCA. Seventeen data sets from ten subjects were evaluated. Results: The number of AIF-relevant pixels, the area under the AIF and the maximum concentration were all lower when the AIF was determined from the MCA compared to the ICA. Additionally, the mean transit time (MTT) and the time to maximum concentration (TTM) were longer in the MCA, complicating the computerized identification of AIF-relevant pixels. Data from one subject, who was examined five times, demonstrated that the intraindividual variance of the measured parameters was markedly lower than the interpersonal variance. Conclusions: It appears to be advantageous to measure the AIF in the ICA rather than the MCA. (orig.) [de

  5. Simultaneous determination of caffeine and some selected polyphenols in Wuyi Rock tea by high-performance liquid chromatography.

    Science.gov (United States)

    Zhao, Feng; Lin, He-Tong; Zhang, Shen; Lin, Yi-Fen; Yang, Jiang-Fan; Ye, Nai-Xing

    2014-04-02

    The primary taste and healthy benefits of tea are mainly attributed to tea polyphenols and caffeine. Due to very many kinds of flavonoid glycosides in tea and the lack of commercial standards of flavonoid glycosides, it is critical to develop a rapid and cheap method for determining flavonoid glycosides of tea. Contents of myricetin glycosides and quercetin glycosides in Wuyi Rock tea were determined by detecting contents of corresponding myricetin and quercetin. Optimizing hydrolysis conditions for hydrolyzing flavonoid glycosides to their corresponding flavonols including quercetin and myricetin in Wuyi Rock tea was a key technology for detecting contents of corresponding myricetin and quercetin. The results showed that hydrolysis at 2 mol/L HCl solution and at 90 °C for 1 h was an optimizing condition for hydrolyzing flavonoid glycosides to myricetin and quercetin in Wuyi Rock tea. Caffeine and seven kinds of polyphenols (GA, EGC, C, EGCG, EC, ECG, and CGA) in 20 samples of Wuyi Rock tea were simultaneously determined using a simple and fast reverse-phase high-performance liquid chromatography procedure coupled with photodiode array detector (RP-HPLC-PDAD). The results indicated that there were significant (P < 0.05) differences of ECG, CGA, ECG, and myricetin glycosides in 'Wuyi Rougui' and 'Wuyi Shuixian', which were credited with causing the difference in taste between these two cultivar of Wuyi Rock tea. The study may be useful for clarifying the cause of "cultivated varieties flavor" of Wuyi Rock tea.

  6. Method validation and measurement uncertainty for the simultaneous determination of synthetic phenolic antioxidants in edible oils commonly consumed in Korea.

    Science.gov (United States)

    Kim, Jae-Min; Choi, Seung-Hyun; Shin, Gi-Hae; Lee, Jin-Ha; Kang, Seong-Ran; Lee, Kyun-Young; Lim, Ho-Soo; Kang, Tae Seok; Lee, Ok-Hwan

    2016-12-15

    This study investigated a method for the validation and determination of measurement uncertainty for the simultaneous determination of synthetic phenolic antioxidants (SPAs) such as propyl gallate (PG), octyl gallate (OG), dodecyl gallate (DG), 2,4,5-trihydroxy butyrophenone (THBP), tert-butylhydroquinone (TBHQ), butylated hydroxyanisole (BHA), and butylated hydroxytoluene (BHT) in edible oils commonly consumed in Korea. The validated method was able to extract SPA residues under the optimized HPLC-UV and LC-MS/MS conditions. Furthermore, the measurement of uncertainty was evaluated based on the precision study. For HPLC-UV analysis, the recoveries of SPAs ranged from 91.4% to 115.9% with relative standard deviations between 0.3% and 11.4%. In addition, the expanded uncertainties of the SPAs ranged from 0.15 to 5.91. These results indicate that the validated method is appropriate for the extraction and determination of SPAs and can be used to verify the safety of edible oil products containing SPAs residues. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Simultaneous Determination of Hormonal Residues in Treated Waters Using Ultrahigh Performance Liquid Chromatography-Tandem Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Rayco Guedes-Alonso

    2013-01-01

    Full Text Available In the last years, hormone consumption has increased exponentially. Because of that, hormone compounds are considered emerging pollutants since several studies have determinted their presence in water influents and effluents of wastewater treatment plants (WWTPs. In this study, a quantitative method for the simultaneous determination of oestrogens (estrone, 17β-estradiol, estriol, 17α-ethinylestradiol, and diethylstilbestrol, androgens (testosterone, and progestogens (norgestrel and megestrol acetate has been developed to determine these compounds in wastewater samples. Due to the very low concentrations of target compounds in the environment, a solid phase extraction procedure has been optimized and developed to extract and preconcentrate the analytes. Determination and quantification were performed by ultrahigh performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS. The method developed presents satisfactory limits of detection (between 0.15 and 9.35 ng·L−1, good recoveries (between 73 and 90% for the most of compounds, and low relative standard deviations (under 8.4%. Samples from influents and effluents of two wastewater treatment plants of Gran Canaria (Spain were analyzed using the proposed method, finding several hormones with concentrations ranged from 5 to 300 ng·L−1.

  8. Antioxidant activity of leaf extracts from different Hibiscus sabdariffa accessions and simultaneous determination five major antioxidant compounds by LC-Q-TOF-MS.

    Science.gov (United States)

    Wang, Jin; Cao, Xianshuang; Jiang, Hao; Qi, Yadong; Chin, Kit L; Yue, Yongde

    2014-12-17

    Hibiscus sabdariffa has gained attention for its antioxidant activity. There are many accessions of H. sabdariffa in the world. However, information on the quantification of antioxidant compounds in different accessions is rather limited. In this paper, a liquid chromatography/quadrupole-time-of-flight mass spectrometry (LC-Q-TOF-MS) method for simultaneous determination of five antioxidant compounds (neochlorogenic acid, chlorogenic acid, cryptochlorogenic acid, rutin, and isoquercitrin) in H. sabdariffa leaves was developed. The method was validated for linearity, sensitivity, precision, repeatability and accuracy. The validated method has been successfully applied for determination of the five analytes in eight accessions of H. sabdariffa. The eight accessions of H. sabdariffa were evaluated for their antioxidant activities by DPPH free radical scavenging assay. The investigated accessions of H. sabdariffa were rich in rutin and exhibited strong antioxidant activity. The two accessions showing the highest antioxidant activities were from Cuba (No. 2) and Taiwan (No. 5). The results indicated that H. sabdariffa leaves could be considered as a potential antioxidant source for the food industry. The developed LC-Q-TOF-MS method is helpful for quality control of H. sabdariffa.

  9. Validated Stability-Indicating RP-HPLC Method for Simultaneous Determination of Clorsulon and Ivermectin Employing Plackett-Burman Experimental Design for Robustness Testing.

    Science.gov (United States)

    Saad, Ahmed S; Ismail, Nahla S; Soliman, Marwa; Zaazaa, Hala E

    2016-01-01

    A sensitive and highly selective stability-indicating gradient HPLC method was developed and validated for simultaneous determination of clorsulon (CLO) and ivermectin (IVM) in the presence of their degradation products. The drugs were subjected to different stress conditions, including acid and alkaline hydrolysis, oxidative, thermal, and photolytic forced degradation. The robustness of the proposed method was assessed using the Plackett-Burman experimental design, the factors affecting system performance were defined, and nonsignificant intervals for the significant factors were determined. The separation was carried out on a ZORBAX SB phenyl analytical column (250 × 4.6 mm id, 5 μm particle size), with gradient elution utilizing 10 mM sodium dihydrogen phosphate and acetonitrile as mobile phase. UV detection was performed for CLO and IVM at 254 nm over a concentration range of 4-140 and 5-50 μg/mL, respectively, with mean percentage recoveries of 99.90 ± 1.30 and 98.59 ± 1.16%, respectively. The proposed method was successfully applied to a pharmaceutical dosage form containing the investigated drugs. The results were statistically compared with the official HPLC methods, and no significant differences were found.

  10. Development of a novel running buffer for the simultaneous determination of nitrate and nitrite in human serum by capillary zone electrophoresis.

    Science.gov (United States)

    Miyado, Takashi; Nagai, Hidenori; Takeda, Sahori; Saito, Keiitsu; Fukushi, Keiichi; Yoshida, Yasukazu; Wakida, Shin-ichi; Niki, Etsuo

    2003-10-03

    In order to improve NO2- peak height and obtain a convenient buffer system for the assay of nitrogen monooxide metabolites, we developed a novel running buffer for the simultaneous determination of nitrite and nitrate in human serum by capillary electrophoresis. The addition of cetyltrimethylammonium chloride to the running buffer resulted in high-speed separation using reverse electroosmotic flow. Highly sensitive determination was also achieved using stacking with 10-fold diluted sample solutions. The samples were injected hydrodynamically for 100 s into a 50 cm x 75 microm I.D. capillary. The separation voltage was 10 kV (negative polarity). UV detection was performed at 214 nm. We obtained complete separation of nitrite and nitrate in deproteinized human serum within 6 min with optimum analytical conditions. Linear calibration curves for nitrite and nitrate for both peak height and peak area were obtained with standard addition method. The limits of detection obtained at a signal-to-noise ratio of 3 for nitrite and nitrate were 4.1 and 2.0 microM, while the values of relative standard deviation of peak height were 2.4 and 2.6%, respectively.

  11. Simultaneous determination of amino acids and neurotransmitters in plasma samples from schizophrenic patients by hydrophilic interaction liquid chromatography with tandem mass spectrometry.

    Science.gov (United States)

    Domingues, Diego Soares; Crevelin, Eduardo José; de Moraes, Luiz Alberto Beraldo; Cecilio Hallak, Jaime Eduardo; de Souza Crippa, José Alexandre; Costa Queiroz, Maria Eugênia

    2015-03-01

    A sensitive, reproducible, and rapid method was developed for the simultaneous determination of underivatized amino acids (aspartate, serine, glycine, alanine, methionine, leucine, tyrosine, and tryptophan) and neurotransmitters (glutamate and γ-aminobutyric acid) in plasma samples using hydrophilic interaction liquid chromatography coupled to triple quadrupole tandem mass spectrometry. The plasma concentrations of amino acids and neurotransmitters obtained from 35 schizophrenic patients in treatment with clozapine (27 patients) and olanzapine (eight patients) were compared with those obtained from 38 healthy volunteers to monitor the effectiveness of treatment. The chromatographic conditions separated ten target compounds within 3 min. This method presented linear ranges that varied from (lower limit of quantification: 9.7-13.3 nmol/mL) to (upper limit of quantification: 19.4-800 nmol/mL), intra- and interassay precision with coefficients of variation lower than 10%, and relative standard error values of the accuracy ranged from -2.1 to 9.9%. The proposed method appropriately determines amino acids and neurotransmitters in plasma from schizophrenic patients. Compared with the control group (healthy volunteers), the plasma levels of methionine in schizophrenic patients treated with olanzapine are statistically significantly higher. Moreover, schizophrenic patients treated with clozapine tend to have increased plasma levels of glutamate. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. High performance liquid chromatography/ion-trap mass spectrometry for separation and simultaneous determination of ethynylestradiol, gestodene, levonorgestrel, cyproterone acetate and desogestrel.

    Science.gov (United States)

    Matejícek, David; Kubán, Vlastimil

    2007-04-11

    A fast and highly sensitive high performance liquid chromatographic/ion-trap mass spectrometric method (LC/MS) has been developed for simultaneous determination of ethynylestradiol (EE2), gestodene (GES), levonorgestrel (LNG), cyproterone acetate (CPA) and desogestrel (DES). Among three types of sorbents tested (C8, C18 and phenyl) from two suppliers, the best separation was achieved on reverse phase Zorbax SB-Phenyl column using aqueous methanol as a mobile phase. A linear gradient profile from 70 up to 100% (v/v) in 7th min, kept constant at 100% up to 10th min and followed by a negative gradient to 70% of methanol up to 12th min was used for elution. Applicability of electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI) and influence of the mobile phase composition, its flow rate, capillary/vaporizer temperature of API source and in-source fragmentor voltage ionization are discussed. The on-column limits of quantification (10S/N) were 300 pg of EE2, 14 pg of GES and LNG, 4 pg of CPA and 960 pg of DES per injection (1 microL) using APCI with data collection in selected ion monitoring (SIM) mode. The analytical performance of the method was evaluated using the determination of EE2, GES, LNG, CPA and DES in contraceptives and river water samples.

  13. Simultaneous determination of ammonia, dimethylamine, trimethylamine and trimethylamine-N-oxide in fish extracts by capillary electrophoresis with indirect UV-detection

    DEFF Research Database (Denmark)

    Timm Heinrich, Maike; Jørgensen, Bo

    2002-01-01

    A capillary electrophoretic method with indirect UV detection is described for simultaneous determination of ammonia, dimethylamine (DMA), trimethylamine (TMA) and trimethylamine-N- oxide (TMAO) in aqueous extracts of fish, A buffer consisting of 4 mM formic acid, 5 mM copper(II)sulfate and 3 m......M crown ether 18-crown-6 enabled separation of the analytes in 5-10 min. The use of an extended light path capillary technique resulted in a good sensitivity and repeatability. The linear dynamic range, based on a hydrostatic injection at 50 mbar for 2 s, was from the detection limit to at least 2.5 m......M. The detection limit for ammonia, DMA, TMA, and TMAO was less than 0.04 mM, corresponding to 2 mg nitrogen per 100 g fish. As an extra benefit, the method also provided a quantitative determination of potassium, sodium, calcium and magnesium ions. (C) 2002 Elsevier Science Ltd. All rights reserved....

  14. Simultaneous determination of fumonisins B1, B2 and B3 contaminants in maize by ultra high-performance liquid chromatography tandem mass spectrometry

    International Nuclear Information System (INIS)

    Ren Yiping; Zhang Yu; Han Shiyun; Han Zheng; Wu Yongning

    2011-01-01

    The present work developed an analytical method for simultaneous determination of fumonisins B 1 , B 2 and B 3 residues in maize by ultra high-performance liquid chromatography combined with electrospray ionization triple quadrupole tandem mass spectrometry (UHPLC-MS/MS) under the multiple reaction monitoring (MRM) mode, and especially focused on the optimization of extraction, clean-up, UHPLC separation and MS/MS parameters. The method involves addition of fumonisins isotope internal standards, extraction with a mixture of acetonitrile and water and clean-up with solid-phase extraction (SPE) cartridges before UHPLC-MS/MS analysis. A single-laboratory method validation was conducted by testing three different spiking levels for repeatability and recovery according to International Union of Pure and Applied Chemistry (IUPAC) guidelines. The LOQ of FB 1 , FB 2 and FB 3 were 1.50, 1.65 and 0.4 μg kg -1 , respectively, which were lower than the criteria of EU, USA and other countries regarding minimum residue limits of fumonisins in foods including baby foods and feedstuffs. Recoveries of three fumonisins ranged from 80.9% to 97.0% with RSD values of 2.4-11.1%.The advantages of this method include simple pretreatment, rapid determination and high sensitivity, and it fulfills the requirements for food analysis with respect to minimum residue limits of fumonisins in various countries.

  15. Development and Validation of a Reversed-phase HPLC Method for Simultaneous Determination of Aspirin, Atorvastatin Calcium and Clopidogrel Bisulphate in Capsules.

    Science.gov (United States)

    Londhe, S V; Deshmukh, R S; Mulgund, S V; Jain, K S

    2011-01-01

    A simple, accurate, rapid and precise isocratic reversed-phase high-performance liquid chromatographic method has been developed and validated for simultaneous determination of aspirin, atorvastatin calcium and clopidogrel bisulphate in capsules. The chromatographic separation was carried out on an Inertsil ODS analytical column (150×4.6 mm; 5 μm) with a mixture of acetonitrile:phosphate buffer pH 3.0 adjusted with o-phosphoric acid (50:50, v/v) as mobile phase; at a flow rate of 1.2 ml/min. UV detection was performed at 235 nm. The retention times were 1.89, 6.6 and 19.8 min. for aspirin, atorvastatin calcium and clopidogrel bisulphate, respectively. Calibration plots were linear (r(2)>0.998) over the concentration range 5-30 μg/ml for atorvastatin calcium and 30-105 μg/ml for aspirin and clopidogrel bisulphate. The method was validated for accuracy, precision, specificity, linearity, and sensitivity. The proposed method was successfully used for quantitative analysis of capsules. No interference from any component of pharmaceutical dosage form was observed. Validation studies revealed that method is specific, rapid, reliable, and reproducible. The high recovery and low relative standard deviation confirm the suitability of the method for routine determination of aspirin, atorvastatin calcium and clopidogrel bisulphate in bulk drug and capsule dosage form.

  16. Simultaneous determination of urinary parabens, bisphenol A, triclosan, and 8-hydroxy-2'-deoxyguanosine by liquid chromatography coupled with electrospray ionization tandem mass spectrometry.

    Science.gov (United States)

    Ren, Lu; Fang, Jianzhang; Liu, Guihua; Zhang, Jianqing; Zhu, Zhou; Liu, Honghe; Lin, Kai; Zhang, Huimin; Lu, Shaoyou

    2016-04-01

    A simple and fast method was developed for the simultaneous determination of five parabens, bisphenol A (BPA), triclosan (TCS), and 8-hydroxy-2'-deoxyguanosine (8-OHdG) in human urine using liquid chromatography coupled with electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS). The solid-phase extraction (SPE) procedure, chromatographic conditions, and MS/MS parameters were optimized to achieve maximum sensitivity and accuracy for the analytes. The validation results showed that the correlation coefficients (R (2)) and recoveries ranged from 0.999 to 1 and 83.9 to 109.9 %, respectively, and the intra-day and inter-day precisions (relative standard deviation, RSD) were within the range of 1.3-8.5 % and 1.3-9.0 %, respectively. The limits of detection for the analytes ranged from 0.001 to 0.05 μg/L. The method was successfully employed to determine parabens, BPA, TCS, and 8-OHdG in urine samples from school students in Guangzhou, China. The results showed that methyl, ethyl, n-propyl parabens, BPA, TCS, and 8-OHdG were frequently detected in urine samples. n-Butyl and benzyl parabens were only detected in a part of the samples due to their low concentrations in urine.

  17. A salting out-acetonitrile homogeneous extraction coupled with gas chromatography-mass spectrometry method for the simultaneous determination of thirteen N-nitrosamines in skin care cosmetics.

    Science.gov (United States)

    Dong, Hao; Guo, Xindong; Xian, Yanping; Luo, Haiying; Wang, Bin; Wu, Yuluan

    2015-11-27

    A sensitive gas chromatography-mass spectrometry method was established for the simultaneous determination of thirteen N-nitrosamines (NAs) in skin care cosmetics. The cosmetics samples were firstly dispersed by water and subsequently extracted and purified using salting out-acetonitrile homogeneous extraction method. Finally, the extracting solution was concentrated by slow nitrogen gas blowing. All of the samples were separated by INNOWAX capillary chromatographic column, and detected by selected ion monitoring (SIM) mode of gas chromatography-mass spectrometry (GC-MS) and quantified by isotope internal standard method. The method was validated for linearity and range, accuracy, precision and sensitivity. Under the optimized condition, the calibration curves were linear over the selected concentration ranges of 2-500μg/L for all the thirteen analytes, with calculated coefficients of determination (R(2)) of greater than 0.996. The limits of detection (LODs) and the limits of quantitation (LOQs) of the method were 3-15μg/kg and 10-50μg/kg, respectively. Recoveries were calculated at three levels of concentration spiked in two kinds of cosmetics (skin care cream and water). The values were found between 93.8% and 121.0% with relative standard deviation (RSD) values of 2.5-7.2% for intra-day precision (n=6) and 3.3-6.7% for inter-day precision (n=5). The method was successfully applied to analyze twenty-two cosmetics samples and N-nitrosodimethylamine (NDMA) was detected in one sample with the concentration of 207μg/kg. Copyright © 2015 Elsevier B.V. All rights reserved.

  18. D-Optimal mixture design optimization of an HPLC method for simultaneous determination of commonly used antihistaminic parent molecules and their active metabolites in human serum and urine.

    Science.gov (United States)

    Kanthiah, Selvakumar; Kannappan, Valliappan

    2017-08-01

    This study describes a specific, precise, sensitive and accurate method for simultaneous determination of hydroxyzine, loratadine, terfenadine, rupatadine and their main active metabolites cetirizine, desloratadine and fexofenadine, in serum and urine using meclizine as an internal standard. Solid-phase extraction method for sample clean-up and preconcentration of analytes was carried out using Phenomenex Strata-X-C and Strata X polymeric cartridges. Chromatographic analysis was performed on a Phenomenex cyano (150 × 4.6 mm i.d., 5 μm) analytical column. A D-optimal mixture design methodology was used to evaluate the effect of changes in mobile phase compositions on dependent variables and optimization of the response of interest. The mixture design experiments were performed and results were analyzed. The region of ideal mobile phase composition consisting of acetonitrile-methanol-ammonium acetate buffer (40 mm; pH 3.8 adjusted with acetic acid): 18:36:46% v/v/v was identified by a graphical optimization technique using an overlay plot. While using this optimized condition all analytes were baseline resolved in rate and analytes peaks were detected at 222 nm. The proposed bioanalytical method was validated according to US Food and Drug Administration guidelines. The proposed method was sensitive with detection limits of 0.06-0.15 μg/mL in serum and urine samples. Relative standard deviation for inter- and intra-day precision data was found to be <7%. The proposed method may find application in the determination of selected antihistaminic drugs in biological fluids. Copyright © 2017 John Wiley & Sons, Ltd.

  19. A Simultaneous and Continuous Excitation Method for High-Speed Electrical Impedance Tomography with Reduced Transients and Noise Sensitivity

    Directory of Open Access Journals (Sweden)

    Antoine Dupré

    2018-03-01

    Full Text Available This paper presents a concept for soft field tomographic scan of all the projections of electromagnetic waves emanating from an array of electrodes. Instead of the sequential excitation of all pairs of electrodes in the list of all projections, the new method present here consists of a single and continuous excitation. This excitation signal is the linear combination of the excitation signals in the projection set at different AC frequencies. The response to a given projection is discriminated by selecting the corresponding AC frequency component in the signal spectra of the digitally demodulated signals. The main advantage of this method is the suppression of transients after each projection, which is particularly problematic in electrical impedance tomography due to contact impedance phenomena and skin effect. The second benefit over the sequential scan method is the increased number of samples for each measurement for reduced noise sensitivity with digital demodulation. The third benefit is the increased temporal resolution in high-speed applications. The main drawback is the increased number of signal sources required (one per electrode. This paper focuses on electrical impedance tomography, based on earlier work by the authors. An experimental proof-of-concept using a simple 4-electrodes electrical impedance tomographic system is presented using simulations and laboratory data. The method presented here may be extended to other modalities (ultrasonic, microwave, optical, etc..

  20. Gradient high performance liquid chromatography method