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Sample records for ceftizoxime hplc kinetic

  1. Technetium-99m ceftizoxime kit preparation

    OpenAIRE

    Simone Odília Fernandes Diniz; Cristiano Ferrari Siqueira; David Lee Nelson; Josep Martin-Comin; Valbert Nascimento Cardoso

    2005-01-01

    The aim of this work was to prepare a kit of 99mTc-ceftizoxime (99mTc-CFT), with stability and biological activity preserved, able to identify a septic focus (E. coli) in the experimental infection model in rats. The preparation of the CFT kit involved the use of lyophilized solutions containing the antibiotic ceftizoxime and the sodium dithionite reducing agent (6.0 mg/mL). After lyophilization, the kit was reconstituted with 1.0 mL of sodium 99mTc-pertechnetate solution (Na99mTcO4-) with an...

  2. Technetium-99m ceftizoxime kit preparation

    Directory of Open Access Journals (Sweden)

    Simone Odília Fernandes Diniz

    2005-10-01

    Full Text Available The aim of this work was to prepare a kit of 99mTc-ceftizoxime (99mTc-CFT, with stability and biological activity preserved, able to identify a septic focus (E. coli in the experimental infection model in rats. The preparation of the CFT kit involved the use of lyophilized solutions containing the antibiotic ceftizoxime and the sodium dithionite reducing agent (6.0 mg/mL. After lyophilization, the kit was reconstituted with 1.0 mL of sodium 99mTc-pertechnetate solution (Na99mTcO4- with an activity of 370 MBq. The solution was boiled for 10 min and filtered through a cellulose ester filter. The labeling efficiency was on the order of 92%, remaining stable for six hours and the kit remained stable for two months. The biological activity of the 99mTc-CFT was evaluated by diffusion in agar impregnated with E.coli and S. aureus. Seven Wistar rats, weighing from 200 to 250 g, were used for the development of the septic focus. After 24 hours from the induction of the infectious site (E.coli, the animals were anesthetized and 0.1 mL of 99mTc-CFT (37 MBq was injected into the tail veins of the animals. The images were obtained with a gamma camera one, two and six hours after injection and the regions of interest (ROIs were calculated. The diameters of the inhibition halos for 99mTc-CFT were 27.16 ± 0.23 and 27.17 ± 0.20 for S.aureus and E.coli, respectively, while those for the unlabeled CFT were 30.4 ± 0.33 and 29.43 ± 0.26, respectively. The results for the biodistribution of 99mTc-CFT in infected animals furnished a ratio of 1.97 ± 0.31, 2.10 ± 0.42 and 2.01 ± 0.42 for cpm-target/cpm-no target for the one, two and six-hour periods, respectively. The images showed a clear uptake of labeled antibiotic (99mTc-CFT by the infectious site during the experiment. The results attest to the viability of producing a kit with 99m technetium-labeled ceftizoxime for the investigation of infectious processes.O objetivo deste trabalho foi preparar um kit de Tc

  3. Is Ceftizoxime an Appropriate Surrogate for Amikacin in Neonatal Sepsis Treatment? A Randomized Clinical Trial

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    Peyman Salamati

    2011-08-01

    Full Text Available Neonatal sepsis, a life-threatening condition, presents with non-specific clinical manifestations and needs immediate empirical antimicrobial therapy. Choosing an appropriate antibiotic regimen covering the most probable pathogens is an important issue. In this study we compared the effectiveness of ceftizoxime and amikacin in the treatment of neonatal sepsis both in combination with ampicillin. In a randomized clinical trial, all term neonates with suspected sepsis referred to Bahrami hospital during March 2008 to March 2010 were evaluated. Patients were randomly recruited into two groups; one group receiving ampicillin and amikacin and the other ampicillin and ceftizoxime. Blood, urine and cerebrospinal fluid cultures, leukocyte count and C-reactive protein level were measured in all neonates. A total of 135 neonates were evaluated, 65 in amikacin group and 70 in ceftizoxime group. 60 neonates (85.7% in ceftizoxime group and 54 neonates (83.1% in amikacin group responded to the treatment (P= 0.673 and χ2 = 0.178. Only 24 (18% blood samples had a report of positive blood culture. The most frequent pathogen was coagulase negative staphylococcus with the frequency of 58.32% of all positive blood samples. Ceftizoxime in combination with ampicillin is an appropriate antimicrobial regimen for surrogating the combination of ampicillin and amikacin to prevent bacterial resistance against them.

  4. HPLC-Based Method to Evaluate Kinetics of Glucosinolate Hydrolysis by Sinapis alba Myrosinase1

    Science.gov (United States)

    Vastenhout, Kayla J.; Tornberg, Ruthellen H.; Johnson, Amanda L.; Amolins, Michael W.; Mays, Jared R.

    2014-01-01

    Isothiocyanates (ITCs) are one of several hydrolysis products of glucosinolates, plant secondary metabolites which are substrates for the thioglucohydrolase myrosinase. Recent pursuits toward the development of synthetic, non-natural ITCs have consequently led to an exploration of generating these compounds from non-natural glucosinolate precursors. Evaluation of the myrosinase-dependent conversion of select non-natural glucosinolates to non-natural ITCs cannot be accomplished using established UV-Vis spectroscopic methods. To overcome this limitation, an alternative HPLC-based analytical approach was developed where initial reaction velocities were generated from non-linear reaction progress curves. Validation of this HPLC method was accomplished through parallel evaluation of three glucosinolates with UV-Vis methodology. The results of this study demonstrate that kinetic data is consistent between both analytical methods and that the tested glucosinolates respond similarly to both Michaelis–Menten and specific activity analyses. Consequently, this work resulted in the complete kinetic characterization of three glucosinolates with Sinapis alba myrosinase, with results that were consistent with previous reports. PMID:25068719

  5. Characterization of PKACα enzyme kinetics and inhibition in an HPLC assay with a chromophoric substrate.

    Science.gov (United States)

    Luzi, Nicole M; Lyons, Charles E; Peterson, Darrell L; Ellis, Keith C

    2017-09-01

    Here we describe a convenient, inexpensive, and non-hazardous method for the measurement of the kinase activity of the catalytic subunit of cAMP-dependent protein kinase (PKACα). The assay is based on the separation of a substrate peptide labeled with a strong chromophore from the phosphorylated product peptide by high-performance liquid chromatograph (HPLC) and quantification of the product ratiometrically at a wavelength in the visual spectrum (Vis). The utility and reliability of the HPLC-Vis assay were demonstrated by characterizing the kinetic parameters (KM, Vmax) of the new Rh-MAB-Kemptide substrate, a commercially prepared TAMRA-Kemptide substrate, and ATP as well as the potency (IC50, Ki) of the known PKACα inhibitors H89 and PKI(5-24). The advantages of this assay are that it is convenient and inexpensive, uses readily synthesized or commercially available substrates that are shelf-stable, uses a common piece of laboratory equipment, and does not require any hazardous materials such as radioactive γ-(32)P-ATP. The assay format is also highly flexible and could be adapted for the testing of many different kinases by changing the peptide substrate sequence. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. Formation study of Bisphenol A resole by HPLC, GPC and curing kinetics by DSC

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    Kamal Khoudary

    2016-11-01

    Full Text Available The formation study of Bisphenol A (BPA resole resins catalyzed by sodium hydroxide has been studied by HPLC, GPC. Resoles have been synthesized under controlled conditions: 90 °C, F/BPA = 1.5 (R1, 2.0 (R2, and 2.5 (R3. The resole with the high molar ratio has shown lower BPA content remained in the final product. The changes in molecular weights of Bisphenol A (BPA–formaldehyde reaction have been identified by GPC as a result of measurements, an increase in molecular weight has been observed with an increase of reaction time and molar ratio. Curing reaction kinetics of resins as a function of molar ratio have been studied by differential scanning calorimetric DSC technique. The activation energies increased with an increase in molar ratio and molecular weights.

  7. Quality by Design (QbD approach to develop HPLC method for eberconazole nitrate: Application oxidative and photolytic degradation kinetics

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    M. Vamsi Krishna

    2016-09-01

    Full Text Available Stability of eberconazole nitrate (EBZ was investigated using a stability indicating HPLC method. Quality by Design (QbD approach was used to facilitate method development. EBZ was exposed to different stress conditions, including hydrolytic (acid, base, neutral, oxidative, thermal and photolytic. Relevant degradation was found to take place in all the conditions. The degradation of EBZ followed (pseudo first-order kinetics under experimental conditions. The kinetic parameters (rate constant, t1/2, and t90 of the degradation of EBZ were calculated.

  8. Optimization of Extraction, HPLC and Kinetic Studies for Determination of Some Food Tainting Compounds in Different Food Matrices.

    Science.gov (United States)

    El-Kosasy, A M; Hussin, L A; Ayad, Miriam F; Fares, N V

    2015-10-01

    Solid-liquid extraction, ultrasonic-assisted extraction and matrix solid-phase dispersion (MSPD) were optimized and compared in terms of recoveries for the simultaneous extraction of indole (IND) and 2,4-dichlorophenol (DCP) from catfish samples and for the extraction of IND alone from potato samples. Applying high-performance liquid chromatography (HPLC-DAD) procedure using mobile phase of methanol : water (65 : 35) at 280 nm, MSPD was the method of choice for the extraction of IND and DCP from catfish and, also, for IND from potato. The extraction recoveries of MSPD were in the range (97.9-99.7%) and (99.8-100.6%); for IND and DCP, respectively, in catfish samples and (98.4-99.7%) for IND alone in potato samples. Solid-phase extraction (SPE) was chosen the method of choice for the extraction of DCP from fish farms water samples after optimization and comparison with direct sample injection and extraction recoveries were in the range (97.9-100.3%). Kinetics were further studied to follow each of production of IND in catfish during storage at different temperatures and uptake of DCP by tilapia in fish farms water samples using MSPD-HPLC and SPE-HPLC, respectively. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  9. HPLC-DAD and UV-spectrophotometry for the determination of lychnopholide in nanocapsule dosage form: validation and application to release kinetic study.

    Science.gov (United States)

    Branquinho, Renata Tupinambá; Mosqueira, Vanessa Carla Furtado; Kano, Eunice Kazue; de Souza, Jacqueline; Dorim, Diego Dias Ramos; Saúde-Guimarães, Dênia Antunes; de Lana, Marta

    2014-01-01

    Simple and sensitive methods using high-performance liquid chromatography-diode array detection (HPLC-DAD) and ultraviolet (UV)-spectrophotometry were developed and compared to quantify lychnopholide (LYC) in poly-ε-caprolactone nanocapsules and to study its release kinetics. Both methods were validated concerning their specificity, linearity, limits of detection and quantification, precision, accuracy and stability. HPLC-DAD analyses were conducted using an RP C18 column, isocratic elution with a methanol-water (60:40 v/v) mobile phase at 0.8 mL/min flow rate and detection at 265 nm. The linear response (r(2) > 0.999) was obtained within a concentration range of 2-25 µg/mL using HPLC-DAD and 5-40 µg/mL using spectrophotometry. Intra-day and inter-day precision were obtained with low relative standard deviation values. The accuracy of the methods was within the range 98-101% for HPLC-DAD and from 96-100% for UV-spectrophotometry. Both methods were suitable to be applied for the determination of drug loading percentage (>96%) and encapsulation efficiency (>90%). Furthermore, the sensitivity of HPLC-DAD method allows studies of LYC release/dissolution in sink conditions. LYC presented 100% dissolution after 24 h, whereas only 60% of LYC was released from the nanocapsule dosage form, with no burst effect. The methods fulfilled all validation parameters evaluated for LYC quantification in the polymeric nanocapsules and have proven to be accurate, selective and sensitive in the previously mentioned applications.

  10. Investigation of the profile and kinetics of degradation of rivaroxaban using HPLC, TLC-densitometry and LC/MS/MS: Application to pre-formulation studies

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    Mohamed A. Abdallah

    2015-06-01

    Full Text Available Rivaroxaban (RIVA, an amide group-containing oral anticoagulant was subjected to stress conditions commonly required for the registration of pharmaceuticals: base and acid-catalyzed hydrolysis (0.1 M, 60 °C, 3–6 h, oxidation (10% H2O2, 24 h, photodegradation (300–800 nm, 24 h and thermal decomposition (50 °C, 6 h. Two major degradation products were separated and identified using TLC and LC/MS/MS, respectively. An orthogonal stability-indicating testing protocol (RP-HPLC and NP-TLC-densitometry was developed and validated according to ICH guidelines. Both assays enabled the determination of RIVA in the presence of its degradation products as well as the kinetics of degradation. Determination was carried out over a concentration range of (5.00–50.00 μg/mL and (0.40–12.00 μg/band with an accuracy of (100.81% ± 1.03 and (100.29% ± 1.08 for HPLC and TLC-densitometry, respectively. Results indicated that RIVA was stable towards oxidation, photodegradation and thermal decomposition but extremely sensitive to hydrolysis. Two major degradation products were detected in the case of base-catalyzed hydrolysis while only one degradation product was detected upon acid-catalyzed hydrolysis. This could be attributed to the presence of amide groups in RIVA structure of different stability profiles. The kinetics of hydrolysis was investigated in more detail and the reaction was found to follow the pseudo first order kinetics, as confirmed by the results of both HPLC and TLC-densitometric assays. The applicability of the assay for the determination of RIVA content and dissolution pattern of the innovator product as well as three generic formulations was demonstrated.

  11. Kinetics study of metaxalone degradation under hydrolytic, oxidative and thermal stress conditions using stability-indicating HPLC method

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    Vamsi Krishna Marothu

    2012-12-01

    Full Text Available An isocratic stability indicating RP-HPLC–UV method is presented for the determination of metaxalone (MET in the presence of its degradation products. The method uses Dr. Maisch C18 column (250 mm×4.6 mm, 5 μm with mobile phase consisting of acetonitrile–potassium dihydrogen orthophosphate buffer with 4 mL of 0.4% triethyl amine (pH 3.0; 10 mM (58:42, v/v at a flow rate of 1.0 mL/min. pH of the buffer was adjusted with o-phosphoric acid. UV detection was performed at 225 nm. The method was validated for specificity, linearity, precision, accuracy, limit of detection, limit of quantification and robustness. The calibration plot was linear over the concentration range of 1–100 μg/mL having a correlation coefficient (r2 of 0.999. Limits of detection and quantification were 0.3 and 1 μg/mL, respectively. Intra-day and inter-day precision (% RSD was 0.65 and 0.79 respectively. The proposed method was used to investigate the degradation kinetics of MET under different stress conditions employed. Degradation of MET followed a pseudo-first-order kinetics, and rate constant (K, time left for 50% potency (t1/2, and time left for 90% potency (t90 were calculated. Keywords: Metaxalone, Degradation kinetics, RP-HPLC–UV

  12. A stability indicating HPLC method for determination of mebeverine in the presence of its degradation products and kinetic study of its degradation in oxidative condition.

    Science.gov (United States)

    Souri, E; Aghdami, A Negahban; Adib, N

    2014-01-01

    An HPLC method for determination of mebeverine hydrochloride (MH) in the presence of its degradation products was developed. The degradation of MH was studied under hydrolysis, oxidative and photolysis stress conditions. Under alkaline, acidic and oxidative conditions, degradation of MH was observed. The separation was performed using a Symmetry C18 column and a mixture of 50 mM KH2PO4, acetonitrile and tetrahydrfuran (THF) (63:35:2; v/v/v) as the mobile phase. No interference peaks from degradation products in acidic, alkaline and oxidative conditions were observed. The linearity, accuracy and precision of the method were studied. The method was linear over the range of 1-100 μg/ml MH (r(2)>0.999) and the CV values for intra-day and inter-day variations were in the range of 1.0-1.8%. The limit of quantification (LOQ) and the limit of detection (LOD) of the method were 1.0 and 0.2 μg/ml, respectively. Determination of MH in pharmaceutical dosage forms was performed using the developed method. Furthermore the kinetics of the degradation of MH in the presence of hydrogen peroxide was investigated. The proposed method could be a suitable method for routine quality control studies of mebeverine dosage forms.

  13. Scintigraphic imaging with technetium-99M-labelled ceftizoxime is a reliable technique for the diagnosis of deep sternal wound infection in rats

    Energy Technology Data Exchange (ETDEWEB)

    Costa, Paulo Henrique Nogueira; Diniz, Simone Odilia Fernandes; Cardoso, Valbert Nascimento; Tarabal, Bernardo; Takenaka, Isabella; Braga, Otavio; Vidigal, Paula Vieira Teixeira; Gelape, Claudio Leo; Araujo, Ivana Duval, E-mail: phnc@uol.com.br [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil)

    2015-07-01

    Purpose: to evaluate whether scintigraphy with technetium-99m-labeled ceftizoxime ({sup 99m}Tc-CFT) can differentiate mediastinitis from aseptic inflammation associated with sternotomy. Methods: twenty female Wistar rats were randomly distributed into four groups: S (control) -partial upper median sternotomy with no treatment; SW (control) - sternotomy and treatment of sternal wounds with bone wax; SB - sternotomy and infection with Staphylococcus aureus; SWB - sternotomy with bone wax treatment and bacterial infection. Scintigraphy with {sup 99m}Tc-CFT was performed eight days after surgery and images were collected 210 and 360 min after infusion of the radiopharmaceutical. Results: no animals exhibited clinical signs of wound infection at the end of the experiment, although histological data verified acute inflammatory response in those experimentally infected with bacteria. Scintigraphic images revealed that tropism of {sup 99m}Tc-CFT to infected sternums was greater than to their non-infected counterparts. Mean counts of radioactivity in bacteria-infected sternal regions (SB and SWB) were significantly higher (p = 0.0007) than those of the respective controls (S and SW).Conclusion: scintigraphy with technetium-99m-labeled ceftizoxime is a method that can potentially detect infection post sternotomy and differentiate from aseptic inflammation in animals experimentally inoculated with S. aureus (author)

  14. kinetics

    Directory of Open Access Journals (Sweden)

    D. E. Panayotounakos

    2002-01-01

    Full Text Available We present the construction of the general solutions concerning the one-dimensional (1D fully dynamic nonlinear partial differential equations (PDEs, for the erosion kinetics. After an uncoupling procedure of the above mentioned equations a second–order nonlinear PDE of the Monge type governing the porosity is derived, the general solution of which is constructed in the sense that a full complement of arbitrary functions (as many as the order is introduced. Afterwards, we specify the above solution according to convenient initial conditions.

  15. HPLC: Early and Recent Perspectives.

    Science.gov (United States)

    Karger, Barry L.

    1997-01-01

    Provides a perspective on what it was like in the early days of high-performance liquid chromatography (HPLC) and several of the key developments. Focuses on the advances in HPLC generally, and more specifically for the biological sciences, that were necessary for the method to reach the preeminent stage of today. Contains 20 references. (JRH)

  16. Literatuuronderzoek HPLC-methoden voor vitamine E

    NARCIS (Netherlands)

    Altena, A.; Hollman, P.C.H.

    1985-01-01

    Doel van dit onderzoek is: het inventariseren van HPLC-methoden voor vitamine E, eventueel in combinatie met vitamine A, in levensmiddelen. Een overzicht van de in de literatuur beschreven HPLC-methoden vanaf ca. 1977 wordt gegeven.

  17. Photoisomerization kinetics of trifloxystrobin.

    Science.gov (United States)

    Banerjee, Kaushik; Ligon, Axel Patrick; Spiteller, Michael

    2005-08-01

    The photoisomerization kinetics of trifloxystrobin (TFS) in acetone under artificial sunlight is reported. HPLC analysis showed the TFS, a strobilurine fungicide of EE conformation, was converted into an equilibrium mixture of four isomers after illumination for 7 h. The isomers were identified as EZ, EE, ZZ, and ZE and were separated in the crystalline form by preparative HPLC and characterized by use of a variety of spectroscopic techniques. The quantum yield and reaction constants for the isomerization reactions were determined. The detailed spectral features of the individual isomers measured by UV, IR, Raman, NMR and mass spectroscopy are presented and compared. The spectra of the isomers were found to be very characteristic, with good analytical significance.

  18. Acquisition of HPLC-Mass Spectrometer

    Science.gov (United States)

    2015-08-18

    31-Jan-2015 Approved for Public Release; Distribution Unlimited Final Report: Acquisition of HPLC -Mass Spectrometer The views, opinions and/or findings...published in peer-reviewed journals: Final Report: Acquisition of HPLC -Mass Spectrometer Report Title The acquisition of the mass spectrometer has been a

  19. Expermental Studies of quantitative evaluation using HPLC

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    Ki Rok Kwon

    2005-06-01

    Full Text Available Methods : This study was conducted to carry out quantitative evaluation using HPLC Content analysis was done using HPLC Results : According to HPLC analysis, each BVA-1 contained approximately 0.36㎍ melittin, and BVA-2 contained approximately 0.54㎍ melittin. But the volume of coating was so minute, slight difference exists between each needle. Conclusion : Above results indicate that the bee venom acupuncture can complement shortcomings of syringe usage as a part of Oriental medicine treatment, but extensive researches should be done for further verification.

  20. HPLC for quality control of polyimides

    Science.gov (United States)

    Young, P. R.; Sykes, G. F.

    1979-01-01

    High Pressure Liquid Chromatography (HPLC) as a quality control tool for polyimide resins and prepregs are presented. A data base to help establish accept/reject criteria for these materials was developed. This work is intended to supplement, not replace, standard quality control tests normally conducted on incoming resins and prepregs. To help achieve these objectives, the HPLC separation of LARC-160 polyimide precursor resin was characterized. Room temperature resin aging effects were studied. Graphite reinforced composites made from fresh and aged resin were fabricated and tested to determine if changes observed by HPLC were significant.

  1. Kinetic Typography

    DEFF Research Database (Denmark)

    van Leeuwen, Theo; Djonov, Emilia

    2014-01-01

    After discussing broad cultural drivers behind the development of kinetic typography, the chapter outlines an approach to analysing kinetic typography which is based on Halliday's theory of transitivity, as applied by Kress and Van Leeuwen to visual images....

  2. [HPLC Characteristic Fingerprint of "Boju" Chrysanthemum morifolium].

    Science.gov (United States)

    Yu, Nian-jun; Yu, Jiao; Zheng, Wei; Cao, Yong; Zheng, Tai-hua; Wang, Yun-qin

    2015-03-01

    To provide a scientific basis for quality control of "Boju" Chrysanthemum morifolium by establishing a HPLC characteristic fingerprint. The HPLC analysis was performed on a Spursil C18 chromatographic column (250 mm x 4. 6 mm, 5 µm), and the mobile phase was acetonitrile-0. 1% phosphoric acid in a gradient mode with the flow rate of 1. 0 mL/min. The detection wavelength was 325 nm and the temperature of column was 30 °C. The common pattern of HPLC characteristic chromatographic profile was established. There were 16 common peaks, five of which were identified in the pattern. The similarities of 10 batches of "Boju" Chrysanthemum monrfolium were evaluated, and all of them were greater than 0. 900. This analysis method of HPLC characteristic chromatographic fingerprint is simple and reproducible, and it can provide a scientific basis for identification and quality evaluation of "Boju" Chrysanthemum monfolium.

  3. Rapid mixing kinetic techniques.

    Science.gov (United States)

    Martin, Stephen R; Schilstra, Maria J

    2013-01-01

    Almost all of the elementary steps in a biochemical reaction scheme are either unimolecular or bimolecular processes that frequently occur on sub-second, often sub-millisecond, time scales. The traditional approach in kinetic studies is to mix two or more reagents and monitor the changes in concentrations with time. Conventional spectrophotometers cannot generally be used to study reactions that are complete within less than about 20 s, as it takes that amount of time to manually mix the reagents and activate the instrument. Rapid mixing techniques, which generally achieve mixing in less than 2 ms, overcome this limitation. This chapter is concerned with the use of these techniques in the study of reactions which reach equilibrium; the application of these methods to the study of enzyme kinetics is described in several excellent texts (Cornish-Bowden, Fundamentals of enzyme kinetics. Portland Press, 1995; Gutfreund, Kinetics for the life sciences. Receptors, transmitters and catalysis. Cambridge University Press, 1995).There are various ways to monitor changes in concentration of reactants, intermediates and products after mixing, but the most common way is to use changes in optical signals (absorbance or fluorescence) which often accompany reactions. Although absorbance can sometimes be used, fluorescence is often preferred because of its greater sensitivity, particularly in monitoring conformational changes. Such methods are continuous with good time resolution but they seldom permit the direct determination of the concentrations of individual species. Alternatively, samples may be taken from the reaction volume, mixed with a chemical quenching agent to stop the reaction, and their contents assessed by techniques such as HPLC. These methods can directly determine the concentrations of different species, but are discontinuous and have a limited time resolution.

  4. HPLC determination of selected incestisides in cosmetic

    OpenAIRE

    Kameníčková, Daniela

    2013-01-01

    Charles University in Prague, Faculty of Pharmacy in Hradec Králové Department of Analytical Chemistry Candidate: Daniela Kameníčková Supervisor: Doc. RNDr. Dalibor Šatínský, Ph.D. Title of Diploma Thesis: HPLC determination of selected incestisides in cosmetic Active ingredients fenoxycarb and permethrin were determined in cosmetic anti- parasitic product Arpalit® Neo shampoo against parasites with bamboo extract. Analysis was performed by HPLC using RP-Amide column 100 x 3 mm with a particl...

  5. An Inexpensive Digital Gradient Controller for HPLC.

    Science.gov (United States)

    Brady, James E.; Carr, Peter W.

    1983-01-01

    Use of gradient elution techniques in high performance liquid chromatography (HPLC) is often essential for direct separation of complex mixtures. Since most commercial controllers have features that are of marginal value for instructional purposes, a low-cost controller capable of illustrating essential features of gradient elution was developed.…

  6. Kinetic Interface

    DEFF Research Database (Denmark)

    2009-01-01

    A kinetic interface for orientation detection in a video training system is disclosed. The interface includes a balance platform instrumented with inertial motion sensors. The interface engages a participant's sense of balance in training exercises.......A kinetic interface for orientation detection in a video training system is disclosed. The interface includes a balance platform instrumented with inertial motion sensors. The interface engages a participant's sense of balance in training exercises....

  7. [Prime study of Gekko gecko in HPLC fingerprint].

    Science.gov (United States)

    Xu, Yong-Li; Zhang, Yue-Yun; Zhao, Cheng-Jian; Gu, Ying-Le; Huang, Yong; Li, Li

    2012-11-01

    To establish HPLC fingerprint of Gekko gecko. The relative retention time and relative peak area of exteacts of Gekko gecko were determine by HPLC to confirm proper chromatographic condition and obtain the data. Better distribution of relative retention time and relative peak area were shown under the chromatographic condition and the HPLC fingerprint was established. The established HPLC fingerprints of Gekko gecko can be used to identify Gekko gecko and its quality control.

  8. [HPLC fingerprint of Calendula officinalis flower].

    Science.gov (United States)

    Xing, Zhan-Fen; Cheng, Hong-Da; Zhang, Ping-Ping; Gong, Lei; Ma, Li-Ya

    2014-07-01

    To establish an HPLC fingerprint of Calendula officinalis flower for its quality control. Hypersil ODS C18 column (250 mm x 4.6 mm, 5 μm) was used with acetonitrile and water as mobile phase in a gradient mode at the flow rate of 1.0 mL/min. The detection wavelength was 220 nm and the temperature of column was set at 35 degrees C. The similarity was analyzed with the Estimating System of Similarity on the Chinese Medicine Fingerprint Chromatogram. The HPLC fingerprint of Calendula officinalis flower containing eleven peaks was set up. The similarity of Calendula officinalis flower from different habitats was greater than 0.90. This method is easy and reliable, which can be used to judge the habitat and control the quality of Calendula officinalis flower.

  9. HPLC Determination of Taurine in Sports Drinks

    Science.gov (United States)

    Orth, Dale L.

    2001-06-01

    The amino acid taurine (2-aminoethanesulfonic acid) is present as a nutritional supplement in many sports drinks. An experiment, suitable for a junior-senior level instrumental analysis course, is described to measure the amount of taurine in these sports drinks. A pre-column derivatization with Sanger's reagent, 2,4-dinitrofluorobenzene, is followed by an HPLC separation utilizing a gradient elution, and detection at 360 nm.

  10. Retinoid quantification by HPLC/MS(n)

    Science.gov (United States)

    McCaffery, Peter; Evans, James; Koul, Omanand; Volpert, Amy; Reid, Kevin; Ullman, M. David

    2002-01-01

    Retinoic acid (RA) mediates most of the biological effects of vitamin A that are essential for vertebrate survival. It acts through binding to receptors that belong to the nuclear receptor transcription factor superfamily (Mangelsdorf et al. 1994). It is also a highly potent vertebrate teratogen. To determine the function and effects of endogenous and exogenous RA, it is important to have a highly specific, sensitive, accurate, and precise analytical procedure. Current analyses of RA and other retinoids are labor intensive, of poor sensitivity, have limited specificity, or require compatibility with RA reporter cell lines (Chen et al. 1995. BIOCHEM: Pharmacol. 50: 1257-1264; Creech Kraft et al. 1994. BIOCHEM: J. 301: 111-119; Lanvers et al. 1996. J. Chromatogr. B Biomed. Appl. 685: 233-240; Maden et al. 1998. DEVELOPMENT: 125: 4133-4144; Wagner et al. 1992. DEVELOPMENT: 116: 55-66). This paper describes an HPLC/mass spectrometry/mass spectrometry product ion scan (HPLC/MS(n)) procedure for the analysis of retinoids that employs atmospheric pressure chemical ionization MS. The retinoids are separated by normal-phase column chromatography with a linear hexane-isopropanol-dioxane gradient. Each retinoid is detected by a unique series of MS(n) functions set at optimal collision-induced dissociation energy (30% to 32%) for all MS(n) steps. The scan events are divided into three segments, based on HPLC elution order, to maximize the mass spectrometer duty cycle. The all-trans, 9-cis, and 13-cis RA isomers are separated, if desired, by an isocratic hexane-dioxane-isopropanol mobile phase. This paper describes an HPLC/MS(n) procedure possessing high sensitivity and specificity for retinoids.

  11. An Investigation Into HPLC Data Quality Problems

    Science.gov (United States)

    Hooker, Stanford B.; VanHeukelem, Laurie

    2011-01-01

    This report summarizes the analyses and results produced by a five-member investigative team of Government, university, and industry experts, established by NASA HQ. The team examined data quality problems associated with high performance liquid chromatography (HPLC) analyses of pigment concentrations in seawater samples produced by the San Diego State University (SDSU) Center for Hydro-Optics and Remote Sensing (CHORS). This report shows CHORS did not validate the methods used before placing them into service to analyze field samples for NASA principal investigators (PIs), even though the HPLC literature contained easily accessible method validation procedures, and the importance of implementing them, more than a decade ago. In addition, there were so many sources of significant variance in the CHORS methodologies, that the HPLC system rarely operated within performance criteria capable of producing the requisite data quality. It is the recommendation of the investigative team to a) not correct the data, b) make all the data that was temporarily sequestered available for scientific use, and c) label the affected data with an appropriate warning, e.g., "These data are not validated and should not be used as the sole basis for a scientific result, conclusion, or hypothesis--independent corroborating evidence is required."

  12. Automatization for development of HPLC methods.

    Science.gov (United States)

    Pfeffer, M; Windt, H

    2001-01-01

    Within the frame of inprocess analytics of the synthesis of pharmaceutical drugs a lot of HPLC methods are required for checking the quality of intermediates and drug substances. The methods have to be developed in terms of optimal selectivity and low limit of detection, minimum running time and chromatographic robustness. The goal was to shorten the method development process. Therefore, the screening of stationary phases was automated by means of switching modules equipped with 12 HPLC columns. Mobile phase and temperature could be optimized by using Drylab after evaluating chromatograms of gradient elutions performed automatically. The column switching module was applied for more than three dozens of substances, e.g. steroidal intermediates. Resolution (especially of isomeres), peak shape and number of peaks turned out to be the criteria for selection of the appropriate stationary phase. On the basis of the "best" column the composition of the "best" eluent was usually defined rapidly and with less effort. This approach leads to savings in manpower by more than one third. Overnight, impurity profiles of the intermediates were obtained yielding robust HPLC methods with high selectivity and minimized elution time.

  13. Kinetics and

    Directory of Open Access Journals (Sweden)

    Mojtaba Ahmadi

    2016-11-01

    Full Text Available The aqueous degradation of Reactive Yellow 84 (RY84 by potassium peroxydisulfate (K2S2O8 has been studied in laboratory scale experiments. The effect of the initial concentrations of potassium peroxydisulfate and RY84, pH and temperature on RY84 degradation were also examined. Experimental data were analyzed using first and second-order kinetics. The degradation kinetics of RY84 of the potassium peroxydisulfate process followed the second-order reaction kinetics. These rate constants have an extreme values similar to of 9.493 mM−1min−1 at a peroxydisulfate dose of 4 mmol/L. Thermodynamic parameters such as activation (Ea and Gibbs free energy (ΔG° were also evaluated. The negative value of ΔGo and Ea shows the spontaneous reaction natural conditions and exothermic nature.

  14. Kinetic Biochemistry

    OpenAIRE

    Jäntschi, Lorentz

    2003-01-01

    Mathematics and computer programming have a major contribution to chemistry. Two directions can be identified: one that searches and tries (rich) to explain the structural binding and shape of the chemical compounds [1] with major applications in QSPR/QSAR studies [2], and applied sciences such as engineering of materials or agriculture [3]; the second direction is to models the kinetic processes that are involved in chemical reactions [4]. Many such models are available here. The present pap...

  15. Kinetic Biochemistry

    Directory of Open Access Journals (Sweden)

    Lorentz JÄNTSCHI

    2003-03-01

    Full Text Available Mathematics and computer programming have a major contribution to chemistry. Two directions can be identified: one that searches and tries (rich to explain the structural binding and shape of the chemical compounds [1] with major applications in QSPR/QSAR studies [2], and applied sciences such as engineering of materials or agriculture [3]; the second direction is to models the kinetic processes that are involved in chemical reactions [4]. Many such models are available here. The present paper describes three variants of well the known kinetic models and presents the mathematical equations associated with them. The differential equations are numerically solved and fitted with MathCad program. [1] Diudea M., Gutman I., Jäntschi L., Molecular Topology, Nova Science, Huntington, New York, 332 p., 2001, 2002. [2] Diudea M. V., Ed., QSPR / QSAR Studies by Molecular Descriptors, Nova Science, Huntington, New York, 438 p., 2001. [3] Jäntschi L., Microbiology and Toxicology. Phytochemistry Studies (in Romanian, Amici, Cluj-Napoca, 184 p., 2003. [4] Jäntschi L., Unguresan M., Physical Chemistry. Molecular Kinetic and Dynamic (in Romanian, Mediamira, Cluj-Napoca, 159 p., 2001.

  16. Physisorption kinetics

    CERN Document Server

    Kreuzer, Hans Jürgen

    1986-01-01

    This monograph deals with the kinetics of adsorption and desorption of molecules physisorbed on solid surfaces. Although frequent and detailed reference is made to experiment, it is mainly concerned with the theory of the subject. In this, we have attempted to present a unified picture based on the master equation approach. Physisorption kinetics is by no means a closed and mature subject; rather, in writing this monograph we intended to survey a field very much in flux, to assess its achievements so far, and to give a reasonable basis from which further developments can take off. For this reason we have included many papers in the bibliography that are not referred to in the text but are of relevance to physisorption. To keep this monograph to a reasonable size, and also to allow for some unity in the presentation of the material, we had to omit a number of topics related to physisorption kinetics. We have not covered to any extent the equilibrium properties of physisorbed layers such as structures, phase tr...

  17. HPLC determination of caffeine in coffee beverage

    Science.gov (United States)

    Fajara, B. E. P.; Susanti, H.

    2017-11-01

    Coffee is the second largest beverage which is consumed by people in the world, besides the water. One of the compounds which contained in coffee is caffeine. Caffeine has the pharmacological effect such as stimulating the central nervous system. The purpose of this study is to determine the level of caffeine in coffee beverages with HPLC method. Three branded coffee beverages which include in 3 of Top Brand Index 2016 Phase 2 were used as samples. Qualitative analysis was performed by Parry method, Dragendorff reagent, and comparing the retention time between sample and caffeine standard. Quantitative analysis was done by HPLC method with methanol-water (95:5v/v) as mobile phase and ODS as stationary phasewith flow rate 1 mL/min and UV 272 nm as the detector. The level of caffeine data was statistically analyzed using Anova at 95% confidence level. The Qualitative analysis showed that the three samples contained caffeine. The average of caffeine level in coffee bottles of X, Y, and Z were 138.048 mg/bottle, 109.699 mg/bottle, and 147.669 mg/bottle, respectively. The caffeine content of the three coffee beverage samples are statistically different (pcoffee beverage samples were not meet the requirements set by the Indonesian Standard Agency of 50 mg/serving.

  18. [RP-HPLC characteristics of dragon's blood].

    Science.gov (United States)

    Gao, Xiu-Li; Jiang, Qian; Wang, Peng-Jiao; Zhang, Min

    2007-10-01

    To study the fingerprint of dragon's blood resina draconis by high performance liquid chromatography. The samples are extracted with methanol and separated on a Eclipse XDB-C18 column (4.6 mm x 150 mm, 5 microm) with the mobile phase of acetonitrile-H2O in gradient mode, and the flow rate was 1.0 mL x min(-1), the detection wavelength was 275 nm and the temperature of column was 40 degrees C. Loureirin B was used as the reference compound. HPLC fingerprint of dragon's blood was established and the similarity of the fingerprint was compared. The method is simple, accurate, and can be used to control the quality of dragon's blood.

  19. Development of Reverse-Phase HPLC Method for Simultaneous ...

    African Journals Online (AJOL)

    Erah

    Quantitative analysis was performed on isocratic high performance liquid chromatography system (HPLC, Waters, ... The HPLC system was equipped with a software, Millenium® (Waters, Milford, USA). Chromatographic .... studied. Several binary or ternary eluents were tested using various proportions of solvents including ...

  20. The high performance liquid chromatography (HPLC) analysis of ...

    African Journals Online (AJOL)

    The high performance liquid chromatography (HPLC) analysis of ultraviolet (UV) irradiated chlorophyll a and secondary plant compounds. ... in all the samples leaving a bleached extract suitable for biological assays. Key words: Chlorophyll a, UV radiation, activated charcoal, HPLC, secondary compounds in plant extracts.

  1. Optimizing Chromatographic Separation: An Experiment Using an HPLC Simulator

    Science.gov (United States)

    Shalliker, R. A.; Kayillo, S.; Dennis, G. R.

    2008-01-01

    Optimization of a chromatographic separation within the time constraints of a laboratory session is practically impossible. However, by employing a HPLC simulator, experiments can be designed that allow students to develop an appreciation of the complexities involved in optimization procedures. In the present exercise, a HPLC simulator from "JCE…

  2. Determination of spectinomycin hydrochloride and its related substances by HPLC-ELSD and HPLC-MSn.

    Science.gov (United States)

    Wang, Jian; Hu, Xiaojun; Tu, Ying; Ni, Kunyi

    2006-04-13

    A new and simple high-performance liquid chromatography-evaporative light scattering detection (HPLC-ELSD) method for the determination of spectinomycin hydrochloride and its related substances was developed. The column was Agilent SB-C(18) (250 mm x 4.6 mm, 5 microm). The mobile phase was 25 mM trifluoroacetic acid. The drift tube temperature was 40 degrees C. The pressure of nebulizing gas was 3.5 bar. Good separation of spectinomycin from main related substances could be achieved. The standard curve was rectilinear in the range of 0.07-3.8 mg/ml (r = 0.9997). Precision was 1.0% (R.S.D.). The limit of detection was 6 microg/ml. The method is simple and rapid, and the results are accurate and reproducible. The HPLC-MS(n) method was used to characterize the structures of impurities contained in the spectinomycin. In positive mode, impurities were elucidated by use of electrospray ion trap mass spectrometry in the multi-stage MS full scan mode. The possible structures of impurities C and D in spectinomycin were deduced based on the HPLC-MS(n) data.

  3. Kinetic buffers.

    Science.gov (United States)

    Alibrandi, Giuseppe; Fabbrizzi, Luigi; Licchelli, Maurizio; Puglisi, Antonio

    2015-01-12

    This paper proposes a new type of molecular device that is able to act as an inverse proton sponge to slowly decrease the pH inside a reaction vessel. This makes the automatic monitoring of the concentration of pH-sensitive systems possible. The device is a composite formed of an alkyl chloride, which kinetically produces acidity, and a buffer that thermodynamically modulates the variation in pH value. Profiles of pH versus time (pH-t plots) have been generated under various experimental conditions by computer simulation, and the device has been tested by carrying out automatic spectrophotometric titrations, without using an autoburette. To underline the wide variety of possible applications, this new system has been used to realize and monitor HCl uptake by a di-copper(II) bistren complex in a single run, in a completely automatic experiment. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. [Development of Tianma HPLC fingerprint and discriminant analysis].

    Science.gov (United States)

    Xiao, Jia-Jia; Huang, Hong; Lei, You-Cheng; Lin, Ting-Wen; Ma, Yue; Zhang, Jing; Zhang, Xing-Guo; Zhang, Da-Quan; Lv, Guang-Hua

    2017-07-01

    Tianma(the tuber of Gastrodia eleta) is a widely used and pricy Chinese herb. Its counterfeits are often found in herbal markets, which are the plant materials with similar macroscopic characteristics of Tianma. Moreover, the prices of Winter Tianma(cultivated Tianma) and Spring Tianma(mostly wild Tianma) have significant difference. However, it is difficult to identify the true or false, good or bad quality of Tianma samples. Thus, a total of 48 Tianma samples with different characteristics(including Winter Tianma, Spring Tianma, slice, powder, etc.) and 9 plant species 10 samples of Tianma counterfeits were collected and analyzed by HPLC-DAD-MS techniques. After optimizing the procedure of sample preparation, chromatographic and mass-spectral conditions, the HPLC chromatograms of all those samples were collected and compared. The similarities and Fisher discriminant analysis were further conducted between the HPLC chromatograms of Tianma and counterfeit, Winter Tianma and Spring Tianma. The results showed the HPLC chromatograms of 48 Tianma samples were similar at the correlation coefficient more than 0.848(n=48). Their mean chromatogram was simulated and used as Tianma HPLC fingerprint. There were 11 common peaks on the HPLC chromatograms of Tianma, in which 6 main peaks were chosen as characteristic peaks and identified as gastrodin, p-hydroxybenzyl alcohol, parishin A, parishin B, parishin C, parishin E, respectively by comparison of the retention time, UV and MS data with those of standard chemical compounds. All the six chemical compounds are bioactive in Tianma. However, the HPLC chromatograms of the 10 counterfeit samples were significantly different from Tianma fingerprint. The correlation coefficients between HPLC fingerprints of Tianma with the HPLC chromatograms of counterfeits were less than 0.042 and the characteristic peaks were not observed on the HPLC chromatograms of these counterfeit samples. It indicated the true or false Tianma can be

  5. DETERMINATION AND VALIDATION OF MEBHYDROLINE NAPADISYLATE IN TABLETS BY HPLC

    Directory of Open Access Journals (Sweden)

    Lestyo Wulandari

    2010-06-01

    Full Text Available An accurate and sensitive HPLC method has been developed for the determination of mebhydroline napadisylate in the tablet. The Chromatography was performed on a reversed phase C-18 column, using a mobile phase of acetonitrile : ammonia 25% (80 : 20 v/v at ambient temperature 25±5 °C and UV detection operates at 320 nm in an overall analysis time of about 15 min, based on peak area. This HPLC method is selective, precise, and accurate and can be used for routine analysis of pharmaceutical preparation in industrial quality-control laboratories.   Keywords : HPLC, mebhydroline napadisylate, validation

  6. Determination of carbonyl compounds in air by HPLC; Determinacion de compuestos carbonilicos en aire por HPLC

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, S.; Perez, R.M.; Campos, A.; Gonzalez, D.

    1995-07-01

    A method for the determination of seven carbonyl compounds in air is presented. The procedure involve sampling of air by a Sep-Pak Cartridge impregnated with 2,4-dinitrophenylhydrazine. Elution was done with 3 mL of acetonitrile and the eluate was diluted to 5 mL. The analysis was done by HPLC with UV detection and external standard method quantification. It has been achieved relative standard deviations about 5% and detection limits of 80 ng/cartridge for formaldehyde, acetaldehyde and acetoacetonitrile. Three different types of samples (rural, urban, petrol emission) were successfully analyzed. (Author) 12 refs.

  7. Kinetic Studies of Biological Interactions By Affinity Chromatography

    OpenAIRE

    Schiel, John E.; Hage, David S.

    2009-01-01

    The rates at which biological interactions occur can provide important information on the mechanism and behavior of such processes in living systems. This review will discuss how affinity chromatography can be used as a tool to examine the kinetics of biological interactions. This approach, referred to here as biointeraction chromatography, uses a column with an immobilized binding agent to examine the association or dissociation of this agent with other compounds. The use of HPLC-based affin...

  8. Improved RP-HPLC method for determination of bovine lactoferrin and its proteolytic degradation in simulated gastrointestinal fluids.

    Science.gov (United States)

    Yao, Xudong; Bunt, Craig; Cornish, Jillian; Quek, Siew-Young; Wen, Jingyuan

    2013-02-01

    The objective of this study was to qualitatively and quantitatively evaluate bovine lactoferrin (bLf) and its stability using a rapid RP-HPLC method. bLf could be rapidly detected within 20 min and quantitated at levels down to 5 µg/mL, and the equation of linearity was y = 86.10x + 178.31 with the correlation coefficient (r(2)) 0.9997. Quantitative data obtained in the present study proved the improved RP-HPLC method to be a sensitive and accurate analytical tool for bLf determination. The proteolytic cleavage of bLf in simulated human gastrointestinal fluids was further analyzed by RP-HPLC, and found to follow pseudo-first-order kinetics. The typical equation obtained by pepsin was log(10) [A(t)]/[A(0)] = -0.03x (r(2) = 0.85), and log(10) [A(t)]/[A(0)] = -0.01x (r(2) = 0.81) for trypsin and chymotrypsin combination. Pepsinolysis of bLf in simulated gastric fluid was relatively fast with the half-life t(1/2) 23.1 min. The digestion of bLf in simulated intestinal fluid was slower with about a 3-fold increase in half-life (69.3 min). After the complete proteolysis of bLf, small cleaved peptide fragments were fully separated and identified by RP-HPLC. The proteolytic study indicated that this validated RP-HPLC was able to evaluate bLf stability though monitoring the derivatization products. Copyright © 2012 John Wiley & Sons, Ltd.

  9. A Simple HPLC Bioanalytical Method for the Determination of ...

    African Journals Online (AJOL)

    Purpose: To develop a simple, accurate, and precise high performance chromatography (HPLC) method with spectrophotometric detection for the determination of doxorubicin hydrochloride in rat plasma. Methods: Doxorubicin hydrochloride and daunorubicin hydrochloride (internal standard, IS) were separated on a C18.

  10. HPLC in natural product analysis: the detection issue.

    Science.gov (United States)

    Wolfender, Jean-Luc

    2009-06-01

    High-performance liquid chromatography (HPLC) is a very powerful and versatile chromatographic technique for the separation of natural products (NPs) in complex matrices, such as crude extracts for selective detection and quantification or general profiling. The method is widespread and has been adapted to the analysis of a broad range of NPs generally without the need for complex sample preparation. The choice of the appropriate detection method in HPLC is crucial because of the diversity of NPs and the fact that there is no single technique for their efficient detection. In this review both qualitative and quantitative applications of HPLC with UV, DAD, FD, ECD, RID, FID, CL, ESLD, CAD, MS, MS-MS, and NMR are covered to provide a general, rather than an exhaustive, overview. The potential and limitations as well as some new trends in HPLC hyphenation are discussed.

  11. A Concise Review on HPLC Method Development and Validation

    OpenAIRE

    Divya Gupta; B. K. Singh

    2016-01-01

    HPLC is an analytical tool which is able to detect, separate and quantify the drug, its various impurities and drug related degradants that can form on synthesis or storage. HPLC method development and validation play important role in new discovery, development and manufacture of pharmaceutical drugs. An analytical procedure is developed to test a defined characteristic of the drug substance or drug product against established acceptance criteria for that characteristic. A number of chromato...

  12. Strategieen voor het optimaliseren van vloeistofchromatografische (HPLC) scheidingen

    OpenAIRE

    Goewie; C.E.

    1985-01-01

    Dit rapport biedt een overzicht van de meest recente methoden voor optimalisering van HPLC scheidingen. Het is toegespitst op de problematiek van analyses, zoals regelmatig voorkomend binnen de praktijk van de residu-analyse. Voor het optimaliseren van HPLC scheidingen kunnen verschillende strategieen gevolgd worden. Uitgaande van fysisch-chemische theoretische principes kan men vrij snel afleiden welke combinaties van stationaire en mobiele fasen voor bepaalde typen te chromatograferen compo...

  13. HPLC analysis of closed, open, and reflex eye tear proteins

    OpenAIRE

    Sitaramamma T; Shivaji S; Rao Gullapalli

    1998-01-01

    Changes in the closed, open and reflex eye tear proteins of normal subjects were compared and analysed. Tear proteins were resolved by high-performance liquid chromatography (HPLC) utilising both gel filtration (P-300 SW) and reverse-phase (C-18) columns and the HPLC fractions were further analysed by sodium dodecyl sulphate - polyacrylamide gel electrophoresis (SDS-PAGE) under reducing and non-reducing conditions. The protein composition of the closed-eye tear was significantly different fro...

  14. [HPLC fingerprinting of total glycosides of Swertia franchetiana].

    Science.gov (United States)

    Tian, Wei; Chen, Zhao-hui; Zhai, Jing; Chen, Li-ren; Li, Yong-min

    2005-05-01

    To establish a sensitive and specific HPLC method for controlling the quality of total glycosides from Swertia franchetiana H. Smith. HPLC method was applied for quality and quantitative assessment of the pharmaceutical extracts from Swertia franchetiana H. Smith. The preparation of sample, the HPLC column, mobile phase, elution mode (isocratic or gradient) and gradient program were optimized in order to obtain HPLC profile. The HPLC system consisted of a SPD-1OAvp pump, SPD-M1OAVP photodiode-array detector (PAD), SIL-10ADVP auto injector. Data were acquired and processed with the CLASS-VP6.1 workstation. HPLC analysis was performed on a Kromasil C18 column (250 mm x 4. 6 mm ID, 5 microm) with methanol and water as mobile phase. The column temperature was set up at 40 degrees C and the flow-rate was 1 mL x min(-1). The reference solution of chemical standards and sample were injected into HPLC system, separately. The HPLC chromatographic fingerprinting of the total glycosides, showing 16 characteristic peaks which were partitioned into three parts: one peak in 0-10 min of retention time, nine peaks containing main 1-7 peaks in 10-15 min of retention time, 6 peaks in 15-30 min of retention time, was established from 10 lots of their products. By comparison of the retention time and the on-line UV spectra and their molecule weights of chemical standards, peak 1-7 were identified as swertiamarin (1), gentiopicroside (2), sweroside (3), isoorientin (4), swertisin (5), isoswertisin (6) and swetianolin (7), respectively. The ratios of peak area between 1-16 were in their extent. Moreover, comparison of the HPLC profiles of the total glycosides, the extracts prepared using another process and the plant indicated that they were closely related to each other. The HPLC profiles and quantitative assessment of the total glycosides from Swertia franchetiana H. Smith with high specificity can be used to control their quality and assure lot to lot consistency.

  15. Enzyme kinetics of hevamine, a chitinase from the rubber tree Hevea brasiliensis

    NARCIS (Netherlands)

    Bokma, Evert; Barends, Thomas; Terwisscha van Scheltinga, Anke C.; Dijkstra, Bauke W.; Beintema, Jaap J.

    2000-01-01

    The enzyme kinetics of hevamine, a chitinase from the rubber tree Hevea brasiliensis, were studied in detail with a new enzyme assay. In this assay, the enzyme reaction products were derivatized by reductive coupling to a chromophore, Products mere separated by HPLC and the amount of product was

  16. Vergelijking van HPLC-methoden voor de bepaling van pentachloorfenol in houtmonsters

    OpenAIRE

    Goewie; C.E.; Berkhoff; Der, C J

    1986-01-01

    Een vergelijkend onderzoek is verricht naar de bruikbaarheid van verschillende detectiemethoden in combinatie met HPLC voor de analyse van pentachloorfenol in hout. In het onderzoek wordt RP-HPLC met UK en amperometrische detectie beschreven, evenals NP-HPLC met elektroneninvangdetectie. In verschillende houtmonsters kon m.b.v. de NP-HPLC met electroneninvangdetectie 1-50 ppm pentachloorfenol worden aangetoond.

  17. [HPLC fingerprint of ethyl acetate extraction of Saxifraga stolonifera].

    Science.gov (United States)

    Zhou, Mei; Chen, Hua-Guo; Xian, Chun; Huang, Zhi-Jin; Zhou, Xin

    2013-04-01

    To establish an HPLC fingerprint of ethyl acetate extraction of Saxifraga stolonifera. The HPLC analysis was performed on a Diamonsil C18 (4.6 mm x 250 mm, 5 microm) column with isocratic elution of acetonitrile-0.05% phosphoric acid at a flow rate of 1.0 mL x min(-1). The detection wavelength was set at 256 nm and the column temperature was set at 30 degrees C. The HPLC fingerprint of ethyl acetate extraction of S. stolonifera has been established. There were fifteen common peaks, seven of which were identified by reference substances. The RSD of relative retention time was less than 3% in the precision and repeated tests. Eleven samples from different area can be distinguished from their fingerprints. This method is reasonable and reliable and can be used for quality control of S. stolonifera.

  18. Direct 13C NMR Detection in HPLC Hyphenation Mode

    DEFF Research Database (Denmark)

    Wubshet, Sileshi Gizachew; Johansen, Kenneth; Nyberg, Nils

    2012-01-01

    is indubitable in simplifying structural elucidations. In the current study, we demonstrated direct (13)C NMR detection of triterpenoids from a Ganoderma lucidum extract in hyphenation mode. The combined advantage of a cryogenically cooled probe, miniaturization, and multiple trapping enabled the first reported......Solid phase extraction (SPE) was introduced as a crucial step in the HPLC-SPE-NMR technique to enable online analyte enrichment from which proton-detected NMR experiments on submicrogram amounts from complex mixtures were possible. However, the significance of direct-detected (13)C NMR experiments...... application of HPLC-SPE-NMR analysis using direct-detected (13)C NMR spectra. HPLC column loading, accumulative SPE trappings, and the effect of different elution solvents were evaluated and optimized. A column loading of approximately 600 mug of a prefractionated triterpenoid mixture, six trappings...

  19. Light-scattering detection of phospholipids resolved by HPLC.

    Science.gov (United States)

    Descalzo, A M; Insani, E M; Pensel, N A

    2003-09-01

    An improved method for the analysis of phospholipids by normal-phase HPLC is described. Addition of methanol and acetonitrile to a gradient based on 2-propanol/hexane/water promoted a rapid separation of major classes of bovine surfactant phospholipids (PL) by using a conventional silica column. The use of an ELSD permitted an accurate analysis of a mixture of PL. Calibration curves were linear within the range of 5-40 microg with detection limits below 1 microg for PE and PC, and CV ranged from 0.6 to 9.6%. PL present in surfactant homogenates were separated by a solid-phase extraction (SPE) procedure before HPLC analysis. This methodology gave a recovery of 95% and combined SPE-HPLC and quantification of biological PL within a 30-min run. The use of ELSD detection of the eluted compounds was precise, linear, and sensitive.

  20. HPLC method development of active substances in nutraceuticals

    OpenAIRE

    Jägerová, Kateřina

    2013-01-01

    Charles University in Prague, Faculty of Pharmacy in Hradec Králové Department of Analytical Chemistry Candidate: Bc. Kateřina Jägerová Supervisor: Doc. RNDr. Dalibor Šatínský, Ph.D. Title of Diploma Thesis: HPLC method development of active substances determination in nutraceuticals A high performance liquid chromatography (HPLC) method with diode array detection (DAD) was used and validated for the simultaneous determination rutin, troxerutin, diosmin and hesperidin. The method was used for...

  1. A hybrid FIA/HPLC system incorporating monolithic column chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Adcock, Jacqui L. [School of Life and Environmental Sciences, Deakin University, Geelong, Victoria 3217 (Australia); Francis, Paul S. [School of Life and Environmental Sciences, Deakin University, Geelong, Victoria 3217 (Australia)], E-mail: psf@deakin.edu.au; Agg, Kent M. [School of Life and Environmental Sciences, Deakin University, Geelong, Victoria 3217 (Australia); Marshall, Graham D. [GlobalFIA, Fox Island, WA 98333 (United States); Barnett, Neil W. [School of Life and Environmental Sciences, Deakin University, Geelong, Victoria 3217 (Australia)

    2007-09-26

    We have combined the generation of solvent gradients using milliGAT pumps, chromatographic separations with monolithic columns and chemiluminescence detection in an instrument manifold that approaches the automation and separation efficiency of HPLC, whilst maintaining the positive attributes of flow injection analysis (FIA), such as manifold versatility, speed of analysis and portability. As preliminary demonstrations of this hybrid FIA/HPLC system, we have determined six opiate alkaloids (morphine, pseudomorphine, codeine, oripavine, ethylmorphine and thebaine) and four biogenic amines (vanilmandelic acid, serotonin, 5-hydroxyindole-3-acetic acid and homovanillic acid) in human urine, using tris(2,2'-bipyridyl)ruthenium(III) and acidic potassium permanganate chemiluminescence detection.

  2. Identification of Ruscus steroidal saponins by HPLC-MS analysis.

    Science.gov (United States)

    de Combarieu, E; Falzoni, M; Fuzzati, N; Gattesco, F; Giori, A; Lovati, M; Pace, R

    2002-12-01

    A novel HPLC-UV method has been developed for the fingerprint analysis of the steroidal saponins in the rhizomes of three Ruscus species (Ruscus aculeatus, Ruscus hypoglossum and Ruscus colchicus). Saponins were identified by HPLC-ESI-MS. During the study a new major saponin was detected in the rhizomes of R. hypoglossum and R. colchicus. The structure of the new compound was defined as 1-O-[alpha-L-rhamnopyranosyl-(1-->2)-6-O-acetyl-beta-D-galactopyranosyl]-1beta,3beta,22xi,26-tetrahydroxy-furost-5(6)-en-26-O-beta-D-glucopyranoside (8) by spectral analysis. Copyright 2002 Elsevier Science B.V.

  3. On-column deracemization of an atropisomeric biphenyl by quinine-based stationary phase and determination of rotational energy barrier by enantioselective stopped-flow HPLC and CEC.

    Science.gov (United States)

    Tobler, E; Lämmerhofer, M; Mancini, G; Lindner, W

    2001-01-01

    The reversible enantiomerization of axially chiral 2'-dodecyloxy-6-nitrobiphenyl-2-carboxylic acid was studied in the presence of a brush type chiral stationary phase based on O-(tert-butylcarbamoyl) quinine as chiral selector unit by stopped-flow high-performance liquid chromatography (sfHPLC) and capillary electrochromatography (sfCEC). After initial separation of the enantiomers in the first section of the column, the flow was stopped and the resolved species allowed to enantiomerize on-column. From this conversion, which could be determined from the enantiomeric ratios at different enantiomerization times, kinetic rate constants were calculated. By sfHPLC at a constant temperature of 15 degrees C, kinetic rate constants in the presence of the CSP were found to be 4.1 x 10(-5) s(-1) and 2.2 x 10(-5) s(-1) for the (-) and (+)-enantiomers, respectively, corresponding to half-lives of 279 and 530 min. Thus, apparent activation energies of enantiomerization were calculated to be 93.0 and 94.6 kJ mol(-1) for the (-) and (+)-enantiomers. On the macroscopic level, the apparent difference of rotational energy barriers and kinetic rate constants for both enantiomers is reflected as deracemization. For example, starting from a racemic mixture, an enantiomeric excess (ee) of 14% was seen in the stopped-flow HPLC experiment described after an enantiomerization time of 220 min at 15 degrees C, and a maximal ee of 17% can be approximated after infinite enantiomerization time. There is good agreement between HPLC and CEC results as well as their experimental errors, confirming that the new sfCEC technique may be a valuable and convenient tool to study interconversion processes. Copyright 2001 Wiley-Liss, Inc.

  4. Chemical fingerprinting and quantitative analysis of a Panax notoginseng preparation using HPLC-UV and HPLC-MS

    Directory of Open Access Journals (Sweden)

    Shao Qing

    2011-02-01

    Full Text Available Abstract Background Xuesaitong (XST injection, consisting of total saponins from Panax notoginseng, was widely used for the treatment of cardio- and cerebro-vascular diseases in China. This study develops a simple and global quality evaluation method for the quality control of XST. Methods High performance liquid chromatography-ultraviolet detection (HPLC-UV was used to identify and quantify the chromatographic fingerprints of the XST injection. Characteristic common peaks were identified using HPLC with photo diode array detection/electrospray ionization tandem mass spectrometry (HPLC-PDA/ESI-MSn. Results Representative fingerprints from ten batches of samples showed 27 'common saponins' all of which were identified and quantified using ten reference saponins. Conclusion Chemical fingerprinting and quantitative analysis identified most of the common saponins for the quality control of P. notoginseng products such as the XST injection.

  5. Stability-Indicating HPLC Method for the Simultaneous ...

    African Journals Online (AJOL)

    Methods: A stability indicating method for the simultaneous estimation of valsartan and ezetimibe in combined tablet formulation using a RP-HPLC was developed and validated as per ICH guidelines using a symmetry C18 column with a mobile phase comprising phosphate buffer and acetonitrile (58:42 v/v, pH 3.15) with a ...

  6. Validated RP-HPLC Method for Quantification of Phenolic ...

    African Journals Online (AJOL)

    Purpose: To evaluate the total phenolic content and antioxidant potential of the methanol extracts of aerial parts and roots of Thymus sipyleus Boiss and also to determine some phenolic compounds using a newly developed and validated reversed phase high performance liquid chromatography (RP-HPLC) method.

  7. Current HPLC Methods for Assay of Nano Drug Delivery Systems.

    Science.gov (United States)

    Tekkeli, Serife Evrim Kepekci; Kiziltas, Mustafa Volkan

    2017-01-01

    In nano drug formulations the mechanism of release is a critical process to recognize controlled and targeted drug delivery systems. In order to gain high bioavailability and specificity from the drug to reach its therapeutic goal, the active substance must be loaded into the nanoparticles efficiently. Therefore, the amount in biological fluids or tissues and the remaining amount in nano carriers are very important parameters to understand the potential of the nano drug delivery systems. For this aim, suitable and validated quantitation methods are required to determine released drug concentrations from nano pharmaceutical formulations. HPLC (High Performance Liquid Chromatography) is one of the most common techniques used for determination of released drug content out of nano drug formulations, in different physical conditions, over different periods of time. Since there are many types of HPLC methods depending on detector and column types, it is a challenge for the researchers to choose a suitable method that is simple, fast and validated HPLC techniques for their nano drug delivery systems. This review's goal is to compare HPLC methods that are currently used in different nano drug delivery systems in order to provide detailed and useful information for researchers. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  8. SCREENING CORD BLOOD FOR HEMOGLOBINOPATHIES AND THALASSEMIA BY HPLC

    NARCIS (Netherlands)

    VANDERDIJS, FPL; VANDENBERG, GA; SCHERMER, JG; MUSKIET, FD; LANDMAN, H; MUSKIET, FAJ

    We evaluated the use of an HPLC method for screening hemoglobins in cord blood. We studied the genotype frequencies of the structural hemoglobin variants HbS and HbC and the synthesis variants alpha- and beta+-thalassemia in babies born on Curacao. During three months, 67.2% of all (748) newborns

  9. Validated RP-HPLC Method for Quantification of Phenolic ...

    African Journals Online (AJOL)

    method. The antioxidative potential of the samples was evaluated using DPPH and ABTS assays. Phenolics responsible for the antioxidant activity of the plant were quantified by a newly developed and validated RP-HPLC method for the first time. Results: The total phenolic concentration of the aerial parts and roots were ...

  10. [Studies on fingerprints of Centella asiatica by HPLC].

    Science.gov (United States)

    Lu, Qiang; Li, Wan-hong; Hu, Shi-qiang

    2011-01-01

    To study the HPLC fingerprints and establish a sensitive and specific method for controlling the quality of Centella asiatica. HPLC gradient elution was applied for the fingerprints of Centella asiatica. All 16 samples are collected from different habitats of China. The columni was Alltech C18 column (250 mm x 4.6 mm, 5 microm), mobile phase was acetonitrile-water, flow rate was 1.0 ml/min, wavelength was 205 nm. The fingerprint of Centella asiatica was established, 16 samples of different areas of Centella asiatica were detected. There were 15 common peaks in the HPLC fingerprints of Centella asiatica. By comparison with the reference standards and using LC-ESI-MS(n) to corroborate the structure, 5-10 peaks were identified as madecassoside, asiaticoside, quercetin, kaemperol, madecassic acid and asiatic acid respectively. After calculating the similarity of the HPLC fingerprints of 16 habitants, the similarity of different habitats has been bad quite. The method is accurate, reliable and good repeatability. This chromatographic fingerprint method can be used to controll the quality of Centella asiatica.

  11. A Simple HPLC Bioanalytical Method for the Determination of ...

    African Journals Online (AJOL)

    Purpose: To develop a simple, accurate, and precise high performance chromatography (HPLC) method with spectrophotometric detection for the determination of doxorubicin hydrochloride in rat plasma. Methods: Doxorubicin hydrochloride and daunorubicin hydrochloride (internal standard, IS) were separated on a C18 ...

  12. HPLC quantification of phenolic content and assessment of ...

    African Journals Online (AJOL)

    HPLC results showed that the major phenolics present are quercetin, rutin, caffeic acid, garlic acid and quercetin. MEA was able to scavenge diphenyl picryl hydrazyl, hydroxyl and nitric oxide radicals and prevent lipid peroxidation induced by ferrous sulphate at all concentration tested. The toxicology investigation showed ...

  13. ICH guidelines-compliant HPLC-UV method for pharmaceutical ...

    African Journals Online (AJOL)

    ICH guidelines-compliant HPLC-UV method for pharmaceutical quality control and therapeutic drug monitoring of the multi-targeted tyrosine kinase inhibitor pazopanib. ... Oxamniquine (OXA) was used as internal standard (IS). The analytical column used for the separation was Nucleosil CN with dimensions (i.d. 250 × 4.6 ...

  14. Development and Validation of an HPLC Method for the ...

    African Journals Online (AJOL)

    A rapid, sensitive and selective reversed-phase high-performance liquid chromatographic (HPLC) method was developed for simultaneous determination of dextromethorphan hydrobromide (DXM), sodium benzoate (SB) and potassium guaiacolesulfonate (PGS) in cough mixture. The combined drug mixtures were ...

  15. A NEW REVERSE PHASE HPLC METHOD WITH FLUORESCENT ...

    African Journals Online (AJOL)

    A sensitive reverse phase-high performance liquid chromatography (RP-HPLC) method with fluorescent detector (FLD) was developed and optimized for salbutamol sulfate (SS) determination in human plasma. In this regard, mobile phase specifications, extraction procedures and excitation and emission wavelengths were ...

  16. A Stability Indicating HPLC Method for the Determination of ...

    African Journals Online (AJOL)

    Purpose: The present study was undertaken to develop a validated, rapid, simple and economic stability indicating reverse phase HPLC method for estimating meloxicam (MLX) in bulk and commercial preparations. Method: Reversed phase chromatographic analysis was performed on a C18 Hi Q Sil column with ...

  17. Rapid and Reliable HPLC Method for the Determination of Vitamin ...

    African Journals Online (AJOL)

    Purpose: To develop and validate an accurate, sensitive and reproducible high performance liquid chromatographic (HPLC) method for the quantitation of vitamin C in pharmaceutical samples. Method: The drug and the standard were eluted from Superspher RP-18 (250 mm x 4.6 mm, 10ìm particle size) at 20 0C.

  18. HPLC-Chip/MS technology in proteomic profiling.

    Science.gov (United States)

    Vollmer, Martin; van de Goor, Tom

    2009-01-01

    HPLC-chip/MS is a novel nanoflow analytical technology conducted on a microfabricated chip that allows for highly efficient HPLC separation and superior sensitive MS detection of complex proteomic mixtures. This is possible through on-chip preconcentration and separation with fluidic connection made automatically in a leak-tight fashion. Minimum precolumn and postcolumn peak dispersion and uncompromised ease of use result in compounds eluting in bands of only a few nanoliters. The chip is fabricated out of bio-inert polyimide-containing channels and integrated chip structures, such as an electrospray emitter, columns, and frits manufactured by laser ablation technology. Meanwhile, a variety of HPLC-chips differing in design and stationary phase are commercially available, which provide a comprehensive solution for applications in proteomics, glycomics, biomarker, and pharmaceutical discovery. The HPLC-chip can also be easily integrated into a multidimensional separation workflow where different orthogonal separation techniques are combined to solve a highly complex separation problems. In this chapter, we describe in detail the methodological chip usage and functionality and its application in the elucidation of the protein profile of human nucleoli.

  19. Ultratraces of carotenes in tomato purees : HPLC-TLS study

    NARCIS (Netherlands)

    Luterotti, S.; Markovic, K.; Franko, M.; Bicanic, D.D.; Vahcic, N.; Doka, O.

    2003-01-01

    The present study was designed to provide information about (i) the profile of carotene pigments and (ii) trace quantities of lycopene and -carotene left in tomato purées. The ultrasensitive method comprising HPLC and thermal lens spectrometric (TLS) detection enabled us to detect as low as 0.3 and

  20. HPLC/Chemiluminescence Detection of Methamphetamine and Amphetamine in Hair

    National Research Council Canada - National Science Library

    Takayama, Nariaki; Tanaka, Seishi; Kizu, Ryoichi; Hayakawa, Kazuichi

    1998-01-01

    ...) for determining methamphetamine (MA) and its metabolite, amphetamine (AP), in a single hair. MA and AP were extracted from a single hair with a solution of methanol and hydrochloric acid, evaporated to dryness, dansylated, and subjected to CL-HPLC. Bis...

  1. Kinetic polymerization behavior of fluorinated monomers for dental use.

    Science.gov (United States)

    Kadoma, Yoshinori

    2010-10-01

    The kinetic polymerization behavior of 2,2,2-trifluoroethyl methacrylate (TFEMA), 1,1,1,3,3,3-hexafluoroisopropyl methacrylate (HFIPMA), 2,2,2-trifluoroethyl acrylate (TFEA) and 1,1,1,3,3,3-hexafluoroisopropyl acrylate (HFIPA) was determined by isothermal differential scanning calorimetry (DSC) and high-performance liquid chromatography (HPLC) in order to improve the properties of fluorinated powder-liquid adhesive resins. Conversion and heat of polymerization were calculated, and the solubility of the homopolymers in common solvents was examined. Comparison of their polymerization reactivity with that of MMA revealed that the overall rate of polymerization initiated by benzoyl peroxide (BPO) decreased in the order TFEA>MMA>TFEMA>HFIPA>HFIPMA. Based on the retention time of the monomer determined by HPLC, the hydrophobicity of the monomers was found to increase in the order MMAadhesive resins.

  2. Extraction, Separation, and Identification of Phenolic Compounds in Virgin Olive Oil by HPLC-DAD and HPLC-MS.

    Science.gov (United States)

    Tasioula-Margari, Maria; Tsabolatidou, Eleftheria

    2015-08-13

    The aim of this study was to evaluate the recovery of individual phenolic compounds extracted from virgin olive oil (VOO), from different Greek olive varieties. Sufficient recoveries (90%) of all individual phenolic compounds were obtained using methanol as an extraction solvent, acetonitrile for residue solubilization, and two washing steps with hexane. Moreover, in order to elucidate structural characteristics of phenolic compounds in VOO, high performance liquid chromatography with a diode array detector (HPLC-DAD) at 280 and 340 nm and HPLC coupled to electrospray ionization mass spectrometry (HPLC-ESI-MS) in the negative-ion mode were performed. The most abundant phenolic compounds were oleuropein derivatives with m/z 319 and 377 and ligstroside derivatives with m/z 303, 361. Lignans, such as 1-acetoxypinoresinol and pinoresinol were also present in substantial quantities in the phenolic fraction. However, pinoresinol was co-eluted with dialdehydic form of ligstroside aglycone (DAFLA) and it was not possible to be quantified separately. The phenolic extracts, obtained from different VOO samples, yielded similar HPLC profiles. Differences, however, were observed in the last part of the chromatogram, corresponding to isomers of the aldehydic form of ligstroside aglycone. Oxidized phenolic products, originating from secoiridoids, were also detected.

  3. Principles of chemical kinetics

    CERN Document Server

    House, James E

    2007-01-01

    James House's revised Principles of Chemical Kinetics provides a clear and logical description of chemical kinetics in a manner unlike any other book of its kind. Clearly written with detailed derivations, the text allows students to move rapidly from theoretical concepts of rates of reaction to concrete applications. Unlike other texts, House presents a balanced treatment of kinetic reactions in gas, solution, and solid states. The entire text has been revised and includes many new sections and an additional chapter on applications of kinetics. The topics covered include quantitative rela

  4. Introduction to chemical kinetics

    CERN Document Server

    Soustelle, Michel

    2013-01-01

    This book is a progressive presentation of kinetics of the chemical reactions. It provides complete coverage of the domain of chemical kinetics, which is necessary for the various future users in the fields of Chemistry, Physical Chemistry, Materials Science, Chemical Engineering, Macromolecular Chemistry and Combustion. It will help them to understand the most sophisticated knowledge of their future job area. Over 15 chapters, this book present the fundamentals of chemical kinetics, its relations with reaction mechanisms and kinetic properties. Two chapters are then devoted to experimental re

  5. [Studies on HPLC-ELSD fingerprint of the Coleus forskohlii introduced in Tongcheng].

    Science.gov (United States)

    Wu, He-zhen; Yang, Qiao-rong; Yang, Yan-fang; Liu, Yan-wen

    2007-11-01

    To establish HPLC-ELSD fingerprint of Coleus forskohlii. Chromatographic fingerprint of Coleus forskohlii was investigated by HPLC-ELSD and gradient elution mode was applied to chromatographic separation. The HPLC-ELSD fingerprint of Coleus forskohlii was established preliminarily. HPLC-ELSD fingerprint method is repeated and can be used in quality control of Coleus forskohlii. The active constituent in Coleus forskohlii is probably at equal pace between introduced in Tongcheng and provenance.

  6. Synthesis and spectral characterization of 2,2-diphenylethyl glucosinolate and HPLC-based reaction progress curve data for the enzymatic hydrolysis of glucosinolates by Sinapis alba myrosinase

    Directory of Open Access Journals (Sweden)

    Chase A. Klingaman

    2017-02-01

    Full Text Available The data presented in this article are related to the research article, “HPLC-based enzyme kinetics assay for glucosinolate hydrolysis facilitate analysis of systems with both multiple reaction products and thermal enzyme denaturation” (C.K. Klingaman, M.J. Wagner, J.R. Brown, J.B. Klecker, E.H. Pauley, C.J. Noldner, J.R. Mays, [1]. This data article describes (1 the synthesis and spectral characterization data of a non-natural glucosinolate analogue, 2,2-diphenylethyl glucosinolate, (2 HPLC standardization data for glucosinolate, isothiocyanate, nitrile, and amine analytes, (3 reaction progress curve data for enzymatic hydrolysis reactions with variable substrate concentration, enzyme concentration, buffer pH, and temperature, and (4 normalized initial velocities of hydrolysis/formation for analytes. These data provide a comprehensive description of the enzyme-catalyzed hydrolysis of 2,2-diphenylethyl glucosinolate (5 and glucotropaeolin (6 under widely varied conditions.

  7. Vergelijking van HPLC-methoden voor de bepaling van pentachloorfenol in houtmonsters

    NARCIS (Netherlands)

    Goewie; C.E.; Berkhoff; C.J.

    1986-01-01

    Een vergelijkend onderzoek is verricht naar de bruikbaarheid van verschillende detectiemethoden in combinatie met HPLC voor de analyse van pentachloorfenol in hout. In het onderzoek wordt RP-HPLC met UK en amperometrische detectie beschreven, evenals NP-HPLC met elektroneninvangdetectie. In

  8. Application of directly coupled HPLC MMR to separation and characterization of lipoproteins from human serum

    DEFF Research Database (Denmark)

    Daykin, C. A.; Corcoran, O.; Hansen, S. H.

    2001-01-01

    with plasma proteins such as albumin occurred, and this clearly limits quantitation of that species by HPLC peak integration. We also show, for the first time, the application of directly coupled HPLC H-1 NMR spectroscopy to confirm the identification of the three major lipoproteins, The full chromatographic...... by the HPLC separation and that their gross supramolecular organization was intact....

  9. [Studies on fingerprinting of Flos Buddleja by RP-HPLC].

    Science.gov (United States)

    Han, Peng; Cui, Ya-jun; Guo, Hong-zhu; Guo, De-an

    2004-10-01

    To establish fingerprinting of Flos Buddleja by using RP-HPLC for the quality control. The HPLC condition was as follows: Inertsil ODS-3 C18 analytical column (4.6 mm x 250 mm, 5 microm), gredient eluation with MeCN (0.1% TFA)-H2O (0.1%TFA), flow rate 1.0 mL x min(-1), detection wavelength 254 nm. 10 commercial samples were analyzed to establish a fingerprinting. Among the obtained fingerprinting, most of the detected peaks were separated effectively. The accuracy, repeatability and stability of this method were satisfied. The RSDs of relative retention time and area of aimed peaks which existed in all samples wereless than 5%. Theresults were in accordance with the request of fingerprinting. The established fingerprinting can be used for the quality control of Flos Buddleja.

  10. HPLC analysis of neo-clerodane diterpenoids from Teucrium chamaedrys.

    Science.gov (United States)

    Avula, B; Manyam, R B; Bedir, E; Khan, I A

    2003-07-01

    A simple, rapid analytical method for the quantitative determination of nine neo-clerodane diterpenoids was developed. The neo-clerodane diterpenoids present in the plant material and extracts were separated with an acetonitrile-water gradient at a flow rate of 1 mL per minute. The HPLC separation was performed on a Phenomenex Luna C18(2) (150 x 4.6 mm I.D., particle size 5 microm) reversed phase column with detection at 220 nm. The limit of detection was 0.24-0.90 microg/mL. The relative standard deviation (RSD) values for the determination of neo-clerodane diterpenoids in plant extracts were less than 3.20%. This is the first analytical method developed for qualitative and quantitative analysis of nine neo-clerodane diterpenoids by HPLC with PDA detection.

  11. Quantification of Organic Acids in Fermented Shrimp Waste by HPLC

    Directory of Open Access Journals (Sweden)

    Dalia Isabel Sánchez-Machado

    2008-01-01

    Full Text Available This work describes a simple, rapid, and reliable HPLC method for the determination of organic acids in fermented shrimp waste. Lactic, acetic and citric acids were quantified by HPLC with UV detection, on a 250×4.6 mm Extrasil ODS 5-μm column, mobile phase was ultrapure water adjusted with metaphosphoric acid to pH=2.1, flow rate 0.6 mL/min, column temperature 30 °C, and detection wavelength 210 nm. Under these conditions, the recovery (97.5 % and the method repeatability (RSD=6.2 % for lactic acid were of satisfying quality. Organic acids can preserve the quality and nutritive value of fermented shrimp waste.

  12. HPLC-DAD determination of imidacloprid in onion

    OpenAIRE

    Mandić Aljoša; Lazić Sanja; Inđić Dušanka

    2003-01-01

    Imidacloprid is an insecticide most commonly used on vegetables, potato sugar beet, fruit, cereal, maize and rice. Imidacloprid residue has been determined in spiked onion and in onion samples. Sample preparation consisted of dichlormethane extraction of imidacloprid from onion, followed by purification of the obtained extract on a LC-Florisil disposable cartridge. The HPLC-DAD method bas been developed on reversed-phase for separation of imidacloprid with a mixture of 0.01 M phosphate buffer...

  13. Gradient Scouting in Reversed-Phase HPLC Revisited

    Science.gov (United States)

    Alcazar, A.; Jurado, J. M.; Gonzalez, A. G.

    2011-01-01

    Gradient scouting is the best way to decide the most suitable elution mode in reversed-phase high-performance liquid chromatography (RP-HPLC). A simple rule for this decision involves the evaluation of the ratio [delta]t/t[subscript G] (where [delta]t is the difference in the retention time between the last and the first peak and t[subscript G] is…

  14. High performance liquid chromatography (HPLC fingerprints and primary structure identification of corn peptides by HPLC-diode array detection and HPLC-electrospray ionization tandem mass spectrometry

    Directory of Open Access Journals (Sweden)

    Chi Wang

    2016-01-01

    Full Text Available Corn peptides (CPs are reported to have many biological functions, such as facilitating alcohol metabolism, antioxidation, antitumor, antihypertension, and hepatoprotection. To develop a method for quality control, the high-performance liquid chromatography (HPLC system was applied. Twenty-eight common peaks were found in all the CPs of corn samples from Enshi, China, based on which, a fingerprinting chromatogram was established for use in quality control in future research. Subsequently, the major chemical constituents of these common peaks were identified respectively using the HPLC-diode-array detection electrospray ionization tandem mass spectrometry (DAD-ESI-MS/MS system, and 48 peptide fractions were determined ultimately. This was the first time for the majority of these peptides to be reported, and many of them contained amino acids of glutamine (Q, L and A, which might play an important role in the exhibition of the bioactivities of CPs. Many peptides had a similar primary structure to the peptides which had been proven to be bioactive such as facilitating alcohol metabolism, scavenging free radicals, and inhibiting lipid peroxidation. This systematical analysis of the primary structure of CPs facilitated subsequent studies on the relationship between the structures and functions, and could accelerate holistic research on CPs.

  15. HPLC analysis of closed, open, and reflex eye tear proteins

    Directory of Open Access Journals (Sweden)

    Sitaramamma T

    1998-01-01

    Full Text Available Changes in the closed, open and reflex eye tear proteins of normal subjects were compared and analysed. Tear proteins were resolved by high-performance liquid chromatography (HPLC utilising both gel filtration (P-300 SW and reverse-phase (C-18 columns and the HPLC fractions were further analysed by sodium dodecyl sulphate - polyacrylamide gel electrophoresis (SDS-PAGE under reducing and non-reducing conditions. The protein composition of the closed-eye tear was significantly different from that of the open and reflex-eye tear. Secretory IgA (sIgA was the predominant protein in closed eye tears constituting 49% of the total protein compared to 11% in reflex tears, whereas lysozyme was the predominant protein (53% in reflex tears. Levels of lactoferrin, lipocalin and lysozyme were relatively constant in both open and reflex tears. HPLC profiles of the closed-eye tears, upon continuous stimulation of lacrimal glands indicated that sIgA was significantly reduced whereas lactoferrin, lipocalin, and lysozyme were significantly increased. These results indicate that the tear composition upon waking attains that of the open eye within 4 to 5 minutes, and upon continuous stimulation this reflects the reflex-eye tear composition. It also indicates that mechanisms responsible for changes in concentration of constitutive and regulated tear protein with stimulus can be studied successfully using non-invasive methods to collect human tears.

  16. HPLC analysis of closed, open, and reflex eye tear proteins.

    Science.gov (United States)

    Sitaramamma, T; Shivaji, S; Rao, G N

    1998-12-01

    Changes in the closed, open and reflex eye tear proteins of normal subjects were compared and analysed. Tear proteins were resolved by high-performance liquid chromatography (HPLC) utilising both gel filtration (P-300 SW) and reverse-phase (C-18) columns and the HPLC fractions were further analysed by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) under reducing and non-reducing conditions. The protein composition of the closed-eye tear was significantly different from that of the open and reflex-eye tear. Secretory IgA (sIgA) was the predominant protein in closed eye tears constituting 49% of the total protein compared to 11% in reflex tears, whereas lysozyme was the predominant protein (53%) in reflex tears. Levels of lactoferrin, lipocalin and lysozyme were relatively constant in both open and reflex tears. HPLC profiles of the closed-eye tears, upon continuous stimulation of lacrimal glands indicated that sIgA was significantly reduced whereas lactoferrin, lipocalin, and lysozyme were significantly increased. These results indicate that the tear composition upon waking attains that of the open eye within 4 to 5 minutes, and upon continuous stimulation this reflects the reflex-eye tear composition. It also indicates that mechanisms responsible for changes in concentration of constitutive and regulated tear protein with stimulus can be studied successfully using non-invasive methods to collect human tears.

  17. HPLC FOR CONTROL STABILITY OF QUERCETIN INJECTABLE DOSAGE FORM

    Directory of Open Access Journals (Sweden)

    Martynov AV

    2016-12-01

    Full Text Available Introduction. Quercetin is a flavone derivatives which known like a substances with vitamin activity, high antioxidant, antimutagenic and anticarcinogenic activity and many other types of biological activity. Wide usage of quercetin prevents their polyphenolic nature structure which does not allow a high bioavailability of pure quercetin when administered orally. This is associated with a wide spectrum variety of chemical reactions for the phenolic groups: from interaction with amino acid residues in proteins to reactions with amine heterocyclic alkaloids and polysaccharides. In our days Corvitin – one from the number of quercetin based drugs with sufficiently low levels all types toxicity, allergenic and has no irritating action on intravenous administration. In the same time quercetin cannot be used in full measure because of the limited number of publications with analysis methods, especially HPLC. Determining the stability over time of concentrate quercetin solution, as well as determining the stability of the concentrate to the original autoclave sterilization conditions is a promising direction in creating new drugs. Materials and methods The objective was to research quercetin soluble formulation samples in different conditions: 1 fresh dilute concentrate (0.9% sodium chloride; 2 the original dilute concentrate, which was stored at room temperature for 14 days in light and 3 similar to the first sample dilute concentrate, which went before breeding in autoclaving at 120 0 C for 20 minutes. The objects used in the studies were industrial drug-substance quercetin (Sinkea manufactured (China, the original pharmaceutical composition as the soluble form of quercetin for injection and aerosol applications, glycerol (Sigma, Polysorbat 80 (Merk, ethanol 96 %. For the HPLC – analysis, chromatograph "Milichrom A-02" (SiChrom, Knauer (Econova, Novosibirsk, Russia was used. Results and discussion Quercetin was identified using information on its

  18. Chemical Differentiation of Dendrobium officinale and Dendrobium devonianum by Using HPLC Fingerprints, HPLC-ESI-MS, and HPTLC Analyses

    Science.gov (United States)

    Ye, Zi; Dai, Jia-Rong; Zhang, Cheng-Gang; Lu, Ye; Wu, Lei-Lei; Gong, Amy G. W.; Wang, Zheng-Tao

    2017-01-01

    The stems of Dendrobium officinale Kimura et Migo (Dendrobii Officinalis Caulis) have a high medicinal value as a traditional Chinese medicine (TCM). Because of the limited supply, D. officinale is a high priced TCM, and therefore adulterants are commonly found in the herbal market. The dried stems of a closely related Dendrobium species, Dendrobium devonianum Paxt., are commonly used as the substitute; however, there is no effective method to distinguish the two Dendrobium species. Here, a high performance liquid chromatography (HPLC) method was successfully developed and applied to differentiate D. officinale and D. devonianum by comparing the chromatograms according to the characteristic peaks. A HPLC coupled with electrospray ionization multistage mass spectrometry (HPLC-ESI-MS) method was further applied for structural elucidation of 15 flavonoids, 5 phenolic acids, and 1 lignan in D. officinale. Among these flavonoids, 4 flavonoid C-glycosides were firstly reported in D. officinale, and violanthin and isoviolanthin were identified to be specific for D. officinale compared with D. devonianum. Then, two representative components were used as chemical markers. A rapid and reliable high performance thin layer chromatography (HPTLC) method was applied in distinguishing D. officinale from D. devonianum. The results of this work have demonstrated that these developed analytical methods can be used to discriminate D. officinale and D. devonianum effectively and conveniently. PMID:28769988

  19. Qualitative and Quantitative Analysis of Lignan Constituents in Caulis Trachelospermi by HPLC-QTOF-MS and HPLC-UV.

    Science.gov (United States)

    Liu, Xiao-Ting; Wang, Xu-Guang; Yang, Yu; Xu, Rui; Meng, Fan-Hua; Yu, Neng-Jiang; Zhao, Yi-Min

    2015-05-05

    A high-performance liquid chromatography coupled with quadrupole tandem time-of-flight mass (HPLC-QTOF-MS) and ultraviolet spectrometry (HPLC-UV) was established for simultaneous qualitative and quantitative analysis of the major chemical constituents in Caulis Trachelospermi, respectively. The analysis was performed on an Agilent Zorbax Eclipse Plus C18 column (4.6 mm×150 mm, 5 μm) using a binary gradient system of water and methanol, with ultraviolet absorption at 230 nm. Based on high-resolution ESI-MS/MS fragmentation behaviors of the reference standards, the characteristic cleavage patterns of lignano-9, 9'-lactones and lignano-8'-hydroxy-9, 9'-lactones were obtained. The results demonstrated that the characteristic fragmentation patterns are valuable for identifying and differentiating lignano-9,9'-lactones and lignano-8'-hydroxy-9,9'-lactones. As such, a total of 25 compounds in Caulis Trachelospermi were unambiguously or tentatively identified via comparisons with reference standards or literature. In addition, 14 dibenzylbutyrolatone lignans were simultaneously quantified in Caulis Trachelospermi by HPLC-UV method. The method is suitable for the qualitative and quantitative analyses of dibenzylbutyrolatone lignans in Caulis Trachelospermi.

  20. Qualitative and Quantitative Analysis of Lignan Constituents in Caulis Trachelospermi by HPLC-QTOF-MS and HPLC-UV

    Directory of Open Access Journals (Sweden)

    Xiao-Ting Liu

    2015-05-01

    Full Text Available A high-performance liquid chromatography coupled with quadrupole tandem time-of-flight mass (HPLC-QTOF-MS and ultraviolet spectrometry (HPLC-UV was established for simultaneous qualitative and quantitative analysis of the major chemical constituents in Caulis Trachelospermi, respectively. The analysis was performed on an Agilent Zorbax Eclipse Plus C18 column (4.6 mm × 150 mm, 5 μm using a binary gradient system of water and methanol, with ultraviolet absorption at 230 nm. Based on high-resolution ESI-MS/MS fragmentation behaviors of the reference standards, the characteristic cleavage patterns of lignano-9, 9'-lactones and lignano-8'-hydroxy-9, 9'-lactones were obtained. The results demonstrated that the characteristic fragmentation patterns are valuable for identifying and differentiating lignano-9,9'-lactones and lignano-8'-hydroxy-9,9'-lactones. As such, a total of 25 compounds in Caulis Trachelospermi were unambiguously or tentatively identified via comparisons with reference standards or literature. In addition, 14 dibenzylbutyrolatone lignans were simultaneously quantified in Caulis Trachelospermi by HPLC-UV method. The method is suitable for the qualitative and quantitative analyses of dibenzylbutyrolatone lignans in Caulis Trachelospermi.

  1. Solid-phase extraction and HPLC determination of fluoroquinolones in surface waters.

    Science.gov (United States)

    Sturini, Michela; Speltini, Andrea; Pretali, Luca; Fasani, Elisa; Profumo, Antonella

    2009-09-01

    An investigation on filtration procedures and SPE sorbents used for the determination of traces of the most common veterinary fluoroquinolones (FQs), marbofloxacin (MAR) and enrofloxacin (ENR) used as antibacterial agents in cattle and swine farms in the province of Pavia (Italy), was performed in natural waters. The filter composition and the sorbent used in the SPE strongly influence the correct recovery, both in terms of total and dissolved FQs concentration. An accurate comparison among different filters and SPE sorbents showed that a full determination of analytes was possible on nylon filters followed by anionic (WAX) and hydrophilic-lipophilic balance (HLB) resins as SPE. Quantitative analysis was done by chromatography with fluorescence detection (HPLC-FD). Fluoroquinolones recovery was between 90 and 116% with RSD not greater than 10% (sample volume 250 mL). The developed method allowed to determine both dissolved and NOM-absorbed fractions of FQs, therefore a full determination of the analytes was possible. Limits of detection (LOD) and quantification (LOQ) were, respectively, 0.7 and 2.2 ng/L for ENR and 2 and 6 ng/L for MAR. The kinetics of degradation under solar light was explored.

  2. Irreversible processes kinetic theory

    CERN Document Server

    Brush, Stephen G

    2013-01-01

    Kinetic Theory, Volume 2: Irreversible Processes deals with the kinetic theory of gases and the irreversible processes they undergo. It includes the two papers by James Clerk Maxwell and Ludwig Boltzmann in which the basic equations for transport processes in gases are formulated, together with the first derivation of Boltzmann's ""H-theorem"" and a discussion of this theorem, along with the problem of irreversibility.Comprised of 10 chapters, this volume begins with an introduction to the fundamental nature of heat and of gases, along with Boltzmann's work on the kinetic theory of gases and s

  3. NDMA formation by chloramination of ranitidine: Kinetics and mechanism

    KAUST Repository

    Le Roux, Julien

    2012-10-16

    The kinetics of decomposition of the pharmaceutical ranitidine (a major precursor of NDMA) during chloramination was investigated and some decomposition byproducts were identified by using high performance liquid chromatography coupled with mass spectrometry (HPLC-MS). The reaction between monochloramine and ranitidine followed second order kinetics and was acid-catalyzed. Decomposition of ranitidine formed different byproducts depending on the applied monochloramine concentration. Most identified products were chlorinated and hydroxylated analogues of ranitidine. In excess of monochloramine, nucleophilic substitution between ranitidine and monochloramine led to byproducts that are critical intermediates involved in the formation of NDMA, for example, a carbocation formed from the decomposition of the methylfuran moiety of ranitidine. A complete mechanism is proposed to explain the high formation yield of NDMA from chloramination of ranitidine. These results are of great importance to understand the formation of NDMA by chloramination of tertiary amines. © 2012 American Chemical Society.

  4. Quantification of appetite suppressing steroid glycosides from Hoodia gordonii in dried plant material, purified extracts and food products using HPLC-UV and HPLC-MS methods

    NARCIS (Netherlands)

    Janssen, H.-G.; Swindells, C.; Gunning, P.; Wang, W.; Grün, C.; Mahabir, K.; Maharaj, V.J.; Apps, P.J.

    2008-01-01

    High-performance liquid chromatography (HPLC)-UV and HPLC-Mass Spectrometry (MS) methods were developed for the quantitative analysis of the family of Hoodia gordonii steroid glycosides with appetite suppressing properties in dried plant material, in purified and enriched extracts and in various

  5. Chemical Kinetics Database

    Science.gov (United States)

    SRD 17 NIST Chemical Kinetics Database (Web, free access)   The NIST Chemical Kinetics Database includes essentially all reported kinetics results for thermal gas-phase chemical reactions. The database is designed to be searched for kinetics data based on the specific reactants involved, for reactions resulting in specified products, for all the reactions of a particular species, or for various combinations of these. In addition, the bibliography can be searched by author name or combination of names. The database contains in excess of 38,000 separate reaction records for over 11,700 distinct reactant pairs. These data have been abstracted from over 12,000 papers with literature coverage through early 2000.

  6. Thermal kinetic inductance detector

    Science.gov (United States)

    Cecil, Thomas; Gades, Lisa; Miceli, Antonio; Quaranta, Orlando

    2016-12-20

    A microcalorimeter for radiation detection that uses superconducting kinetic inductance resonators as the thermometers. The detector is frequency-multiplexed which enables detector systems with a large number of pixels.

  7. Geometry-controlled kinetics.

    Science.gov (United States)

    Bénichou, O; Chevalier, C; Klafter, J; Meyer, B; Voituriez, R

    2010-06-01

    It has long been appreciated that the transport properties of molecules can control reaction kinetics. This effect can be characterized by the time it takes a diffusing molecule to reach a target-the first-passage time (FPT). Determining the FPT distribution in realistic confined geometries has until now, however, seemed intractable. Here, we calculate this FPT distribution analytically and show that transport processes as varied as regular diffusion, anomalous diffusion, and diffusion in disordered media and fractals, fall into the same universality classes. Beyond the theoretical aspect, this result changes our views on standard reaction kinetics and we introduce the concept of 'geometry-controlled kinetics'. More precisely, we argue that geometry-and in particular the initial distance between reactants in 'compact' systems-can become a key parameter. These findings could help explain the crucial role that the spatial organization of genes has in transcription kinetics, and more generally the impact of geometry on diffusion-limited reactions.

  8. Fundamentals of enzyme kinetics.

    Science.gov (United States)

    Seibert, Eleanore; Tracy, Timothy S

    2014-01-01

    This chapter provides a general introduction to the kinetics of enzyme-catalyzed reactions, with a focus on drug-metabolizing enzymes. A prerequisite to understanding enzyme kinetics is having a clear grasp of the meanings of "enzyme" and "catalysis." Catalysts are reagents that can increase the rate of a chemical reaction without being consumed in the reaction. Enzymes are proteins that form a subset of catalysts. These concepts are further explored below.

  9. Electrochemical kinetics theoretical aspects

    CERN Document Server

    Vetter, Klaus J

    1967-01-01

    Electrochemical Kinetics: Theoretical Aspects focuses on the processes, methodologies, reactions, and transformations in electrochemical kinetics. The book first offers information on electrochemical thermodynamics and the theory of overvoltage. Topics include equilibrium potentials, concepts and definitions, electrical double layer and electrocapillarity, and charge-transfer, diffusion, and reaction overvoltage. Crystallization overvoltage, total overvoltage, and resistance polarization are also discussed. The text then examines the methods of determining electrochemical reaction mechanisms

  10. Kinetics of enzyme-catalyzed cross-linking of feruloylated arabinan from sugar beet

    DEFF Research Database (Denmark)

    Abang Zaidel, Dayang Norulfairuz; Arnous, Anis; Holck, Jesper

    2011-01-01

    the kinetics of HRP catalyzed cross-linking of FA esterified to α-(1,5)-linked arabinans are affected by the length of the arabinan chains carrying the feruloyl substitutions. The kinetics of the HRP-catalyzed cross-linking of four sets of arabinan samples from sugar beet pulp, having different molecular...... weights and hence different degrees of polymerization, were monitored by the disappearance of FA absorbance at 316 nm. MALDI-TOF/TOF-MS analysis confirmed that the sugar beet arabinans were feruloyl-substituted, and HPLC analysis verified that the amounts of diFAs increased when FA levels decreased...

  11. RP-HPLC Determination of Raloxifene in Pharmaceuticl Tablets

    Directory of Open Access Journals (Sweden)

    P. Venkata Reddy

    2006-01-01

    Full Text Available A reverse phase HPLC method is developed for the determination of Raloxifene in pharmaceutical dosage forms. Chromatography was carried out on an inertsil C18 column using a mixture of acetonitrile and phosphate buffer (30:70 v/v as the mobile phase at a flow rate of 1 mL/min. Detection was carried out at 290 nm .The retention time of the drug was 10.609 min. The method produced linear responses in the concentration range of 0.5-200 µg/mL of Raloxifene. The method was found to be applicable for determination of the drug in tablets.

  12. Thermolysis kinetics and thermal degradation compounds of alliin.

    Science.gov (United States)

    Chen, Zixing; Xu, MingJiao; Wang, Chao; Zhou, Hua; Fan, Lokyee; Huang, Xuesong

    2017-05-15

    To investigate thermolysis kinetics and identify degradation compounds, alliin solutions were heated at 60, 80, and 89°C. The degradation compounds of alliin were identified by high performance liquid chromatography-mass spectrometry (HPLC-MS), tandem mass spectrometry (MS/MS) and ultra-pressure liquid chromatography-high resolution mass spectrometry (UPLC-HRMS). The results showed that the thermal degradation kinetic of alliin could be described by a first-order reaction and k=4.38×1017exp (-142494/RT), where k is the reaction rate constant, min-1; R is gas constant; T is the absolute temperature, K. Degraded compounds, including S-allyl-l-cysteine and ethers, such as allyl alanine disulfide, allyl alanine trisulfide, allyl alanine tetrasulfide, dialanine disulfide (cysteine), dialanine trisulfide and dialanine tetrasulfide, were identified by HPLC-MS, MS/MS and UPLC-HRMS. Allyl alanine tetrasulfide was identified for the first time in alliin. The results show that alliin is unstable and significant numbers of organosulfur compounds are generated under high temperature treatment. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Analysis of C-glycosyl flavonoids from South American Passiflora species by HPLC-DAD and HPLC-MS.

    Science.gov (United States)

    Zucolotto, Silvana Maria; Fagundes, Carize; Reginatto, Flávio Henrique; Ramos, Freddy A; Castellanos, Leonardo; Duque, Carmenza; Schenkel, Eloir Paulo

    2012-01-01

    Leaves and fruits of Passiflora species are widely used around the world in popular medicine, mainly as sedatives and tranquilisers. C-glycosyl flavonoids are the main components of these species. To investigate the constituent patterns and to develop a chromatographic method for the characterisation of the C-glycosyl flavonoids profile of the extracts of the leaves and the pericarp of South American Passiflora species. The chemical composition of extracts from the leaves and the fruits' pericarp of Passiflora edulis var. flavicarpa, P. edulis var. edulis, Passiflora alata, Passiflora tripartita var. mollissima, Passiflora quadrangularis, Passiflora manicata and Passiflora ligularis was evaluated for the presence of C-glycosyl flavonoids. Two separate HPLC methods were developed suitable for a diode array detector (DAD) and a MS detector. Separation by HPLC-DAD was achieved on a Luna C-18 column, using solvent A (tetrahydrofuran-isopropanol-acetonitrile) and solvent B (H₃PO₄ 0.5%) in an isocratic elution mode. In the HPLC-MS, the components were separated on a Luna RP-18A column by a gradient elution (water-acetonitrile-formic acid). The presence of C-glycosyl flavonoids was identified in leaves and pericarp of P. edulis var. flavicarpa, P. alata, P. edulis var. edulis and P. tripartita var. molissima, but only in leaf extracts of P. quadrangularis and P. manicata and not at all in P. ligularis. The different species and varieties showed different major constituents. The C-glycosyl flavonoids identified more frequently were orientin, isoorientin, vitexin and isovitexin. The methods established are simple and can be used as a tool for the characterisation and quality control of pharmaceutical preparations containing these Passiflora extracts. Copyright © 2011 John Wiley & Sons, Ltd.

  14. Analysis of coal extracts by HPLC-ESI-MS

    Energy Technology Data Exchange (ETDEWEB)

    Jie Feng; Cui-Ping Ye; Wen-Ying Li; Ke-Chang Xie [Taiyuan University of Technology, Taiyuan (China). Key Laboratory of Coal Science and Technology

    2003-07-01

    In order to get the structure information of the coal pyridine extracts, the methods based on reverse-phase high-performance liquid chromatography (RP-HPLC) with photodiode array detector (PDA) and electro-spray ionization mass spectrometer (ESI-MS) has been developed. For the purpose of classifying the mixture according to the polarity of the compound before HPLC/MS analysis, column chromatography packed with silica gel was applied to separate coal pyridine extracts into three fractions: acetonitrile (lower), chloroform (middle), pyridine (higher). The fraction of chloroform (CHCl{sub 3}) was analyzed in this article. In the mass range of 150-1500amu, the components observed include 314.3/369.1, and 301.3/369.1, which should be the plasticizer in the solvent. Other peaks included a series of molecular ions from the beginning of 541.3amu with m/z difference 74amu (C{sub 3}H{sub 6}O{sub 2} or C{sub 4}H{sub 10}O). 541.3amu (ESI+) is the elemental structure in the series; this implied that the higher molecular mass parts in coal might consist of some basic units. And two valuable compounds containing nitrogen atom were acquired at m/z 393.5amu (C{sub 27}H{sub 39}NO) and 334.5amu (C{sub 20}H{sub 38}N{sub 4}). 11 refs., 5 figs., 1 tab.

  15. Quality control of PET radiopharmaceuticals using HPLC with electrochemical detection.

    Science.gov (United States)

    Nakao, Ryuji; Furutuka, Kenji; Yamaguchi, Masatoshi; Suzuki, Kazutoshi

    2006-04-01

    The usefulness of high-performance liquid chromatography with electrochemical detection (HPLC/ECD) in the quality control of positron emission tomography (PET) radiopharmaceuticals was evaluated for a number of substances. Chromatographic separation was performed using a reversed phase column and acetonitrile or 20 mM sodium phosphate buffer as the mobile phase. The effluent from the column was introduced into an electrochemical detector equipped with a glassy carbon electrode versus Ag/AgCl electrode operated in the direct current mode. In 19 of 21 PET radiopharmaceuticals studied, the compounds and corresponding precursors used in the synthesis of the radiopharmaceuticals could be successfully detected by the HPLC/ECD method. For 17 compounds with electroactive functional groups, such as aliphatic amines, phenols and aromatic amines, the detection limits were ppb levels for a 20-mul injection volume; this was significantly better compared with ultraviolet (UV) detection. This method could be applied to the analysis of [11C]MP4A, useful PET radiopharmaceutical for measuring acetylcholinesterase activity in the brain with no available UV absorbance.

  16. Variable-gradient generator for micro- and nano-HPLC.

    Science.gov (United States)

    Cappiello, Achille; Famiglini, Giorgio; Fiorucci, Chiara; Mangani, Filippo; Palma, Pierangela; Siviero, Antonella

    2003-03-01

    A new, simple device generates accurate nano- and microflow rate gradients from any conventional HPLC system. The core of the new device is represented by an electric-actuated, computer-controlled, multiposition HPLC valve. The valve hosts six reservoirs for as many different mobile-phase compositions of increasing strength. A low flow rate stream pushes the weakest solvent through the column as long as required and at the desired flow rate, until the chromatographic run is started. From this time on, the electric actuation allows one to select which reservoir will be on-line with the column and for how long, thus generating a specific solvent gradient, through a sequence of controlled segments of precise mobile-phase composition. This permits one not only to exactly reproduce the programmed slope but also to achieve different gradient shapes (i.e., linear, convex, concave) for different separation needs. The new device has proven to be reliable and reproducible even at the lowest flow rate tested (250 nL x min(-1)) and in different chromatographic conditions.

  17. Multiple alternative substrate kinetics.

    Science.gov (United States)

    Anderson, Vernon E

    2015-11-01

    The specificity of enzymes for their respective substrates has been a focal point of enzyme kinetics since the initial characterization of metabolic chemistry. Various processes to quantify an enzyme's specificity using kinetics have been utilized over the decades. Fersht's definition of the ratio kcat/Km for two different substrates as the "specificity constant" (ref [7]), based on the premise that the important specificity existed when the substrates were competing in the same reaction, has become a consensus standard for enzymes obeying Michaelis-Menten kinetics. The expansion of the theory for the determination of the relative specificity constants for a very large number of competing substrates, e.g. those present in a combinatorial library, in a single reaction mixture has been developed in this contribution. The ratio of kcat/Km for isotopologs has also become a standard in mechanistic enzymology where kinetic isotope effects have been measured by the development of internal competition experiments with extreme precision. This contribution extends the theory of kinetic isotope effects to internal competition between three isotopologs present at non-tracer concentrations in the same reaction mix. This article is part of a special issue titled: Enzyme Transition States from Theory and Experiment. Published by Elsevier B.V.

  18. [Chromatographic Fingerprinting Study of Zhenyuan Granules Dry Extract by HPLC-DAD and HPLC-MS/MS].

    Science.gov (United States)

    Li, Yuan-yuan; Shan, Jin-feng; Tan, Qing-jie; Wang, Song-lin; Jiang, Jian-lan

    2015-09-01

    To establish a novel, accurate and valid fingerprint method of Zhenyuan granules dry extract by using HPLC-DAD method, to study herbs belonging of fingerprint peaks and to identify some of the chromatographic peaks by HPLC-MS/MS analysis, for providing the basis for scientific evaluation of the quality. The sample solutions were analyzed by an Agilent SB C18 (250 mm x 4.6 mm, 5 µm) column, and gradiently eluted with acetonitrile (containing 0.1% formic acid) and aqueous phase (containing 0.1% formic acid) as the mobile phase. The flow rates were 1.2 mL/min (0~70 min) and 0.8 mL/min (70~150 min); the column temperature was 30 °C; and the detection wavelength was 254 nm. 40 peaks were selected as fingerprint peaks under the optimal chromatographic condition, and the similarity coefficients of 10 batches of Zhenyuan granules dry extract were all greater than 0.98. 27 peaks were tentatively identified with reference to literature data based on their mass spectrometry. The chromatographic fingerprint of Zhenyuan granules is proved to be a reliable method for comprehensive quality control and assessment.

  19. Determination of anthocyanins from camu-camu (Myrciaria dubia) by HPLC-PDA, HPLC-MS, and NMR.

    Science.gov (United States)

    Zanatta, Cinthia Fernanda; Cuevas, Elyana; Bobbio, Florinda O; Winterhalter, Peter; Mercadante, Adriana Z

    2005-11-30

    Camu-camu [Myrciaria dubia (HBK) McVaugh] is a small fruit native to the Amazonian rain forest. Its anthocyanin profile has now been investigated for the first time. Fruits from two different regions of the São Paulo state, Brazil, were analyzed. The major anthocyanins were isolated by high-speed countercurrent chromatography. HPLC-PDA, HPLC-MS/MS, and 1H NMR were used to confirm the identity of the main anthocyanins of camu-camu. Cyanidin-3-glucoside was identified as the major pigment in the fruits from both regions, representing 89.5% in the fruits produced in Iguape and 88.0% in those from Mirandópolis, followed by the delphinidin-3-glucoside, ranging between 4.2 and 5.1%, respectively. Higher total anthocyanin contents were detected in the fruits from Iguape (54.0 +/- 25.9 mg/100 g) compared to those from Mirandópolis (30.3 +/- 6.8 mg/100 g), most likely because of the lower temperatures in the Iguape region.

  20. Extraction and analysis of colourful eggshell pigments using HPLC and HPLC/electrospray ionization tandem mass spectrometry.

    Science.gov (United States)

    Gorchein, A; Lim, C K; Cassey, P

    2009-06-01

    The literature on the pigments of avian eggshells is critically reviewed. Methods using methanolic sulfuric acid or hydrochloric acid to extract eggshell pigments are unsuitable to detect the occurrence of zinc protoporphyrin or zinc biliverdin because they demetallate these compounds. Extraction methods are described here using EDTA and acetonitrile-acetic acid or acetonitrile-dimethyl sulfoxide, which do not demetallate zinc protoporphyrin. Such extracts were prepared from eggshell of the common nighthawk, Chordeiles minor, and from another six bird species. Protoporphyrin and biliverdin were identified and fully characterized by HPLC/electrospray ionization tandem mass spectrometry (HPLC/ESI-MS/MS) in all samples, but none contained zinc protoporphyrin. The zinc complex of biliverdin, claimed to be an additional pigment responsible for eggshell background colours, was labile to EDTA and acid pH and if occurring naturally could not be extracted intact by the published or the modified protocols. An explanation is advanced for the exceptional report that all porphyrins from uroporphyrin to protoporphyrin were found in eggshells of the fowl Gallus domesticus.

  1. Erbium hydride decomposition kinetics.

    Energy Technology Data Exchange (ETDEWEB)

    Ferrizz, Robert Matthew

    2006-11-01

    Thermal desorption spectroscopy (TDS) is used to study the decomposition kinetics of erbium hydride thin films. The TDS results presented in this report are analyzed quantitatively using Redhead's method to yield kinetic parameters (E{sub A} {approx} 54.2 kcal/mol), which are then utilized to predict hydrogen outgassing in vacuum for a variety of thermal treatments. Interestingly, it was found that the activation energy for desorption can vary by more than 7 kcal/mol (0.30 eV) for seemingly similar samples. In addition, small amounts of less-stable hydrogen were observed for all erbium dihydride films. A detailed explanation of several approaches for analyzing thermal desorption spectra to obtain kinetic information is included as an appendix.

  2. Spectrophotometric and HPLC determination of deflazacort in pharmaceutical dosage forms

    Directory of Open Access Journals (Sweden)

    Amarilis Scremin

    2010-06-01

    Full Text Available Deflazacort (DFZ is a glucocorticoid used as an anti-inflammatory and immunosuppressant drug. No official methods are available for DFZ determination in pharmaceutical formulations. The objective of this study was to develop, validate and compare spectrophotometric (UV and colorimetric and high-performance liquid chromatography (HPLC methods, for the quantitative determination of DFZ in tablets and oral suspension. For the UV method, ethanol was used as the solvent, with detection at 244 nm. The colorimetric method was based on the redox reaction with blue tetrazolium in alkaline medium, with detection at 524 nm. The method by HPLC was carried out using a C18 column, mobile phase consisting of acetonitrile:water (80:20, v/v with a flow rate of 1.0 mL min-1 and detection at 244 nm. The methods proved linear (r > 0.999, precise (RSD 97%. Statistical analysis of the results indicated that the UV and HPLC methods were statistically equivalent, while the values obtained for the colorimetric method differed significantly from the other methods.O deflazacorte (DFZ é um fármaco glicocorticóide usado como antiinflamatório e imunossupressor. Métodos oficiais não estão disponíveis para a determinação de DFZ em formas farmacêuticas. Este estudo teve como objetivo desenvolver, validar e comparar métodos por espectrofotometria (UV e colorimetria e cromatografia líquida de alta eficiência (CLAE, na determinação quantitativa de DFZ em comprimidos e suspensão oral. O método por UV utilizou etanol como solvente, com detecção em 244 nm. O método colorimétrico foi baseado na reação de redução com azul de tetrazólio em meio alcalino, com detecção em 524 nm. O método por CLAE utilizou coluna C18; fase móvel constituída de acetonitrila:água (80:20, v/v, com fluxo de 1,0 mL min-1 e detecção em 244 nm. Os métodos foram lineares (r > 0,999; precisos (RSD 97%. As análises estatísticas dos resultados obtidos indicaram que os m

  3. Total chemical synthesis of proteins without HPLC purification.

    Science.gov (United States)

    Loibl, S F; Harpaz, Z; Zitterbart, R; Seitz, O

    2016-11-01

    The total chemical synthesis of proteins is a tedious and time-consuming endeavour. The typical steps involve solid phase synthesis of peptide thioesters and cysteinyl peptides, native chemical ligation (NCL) in solution, desulfurization or removal of ligation auxiliaries in the case of extended NCL as well as many intermediary and final HPLC purification steps. With an aim to facilitate and improve the throughput of protein synthesis we developed the first method for the rapid chemical total on-resin synthesis of proteins that proceeds without a single HPLC-purification step. The method relies on the combination of three orthogonal protein tags that allow sequential immobilization (via the N-terminal and C-terminal ends), extended native chemical ligation and release reactions. The peptide fragments to be ligated are prepared by conventional solid phase synthesis and used as crude materials in the subsequent steps. An N-terminal His6 unit permits selective immobilization of the full length peptide thioester onto Ni-NTA agarose beads. The C-terminal peptide fragment carries a C-terminal peptide hydrazide and an N-terminal 2-mercapto-2-phenyl-ethyl ligation auxiliary, which serves as a reactivity tag for the full length peptide. As a result, only full length peptides, not truncation products, react in the subsequent on-bead extended NCL. After auxiliary removal the ligation product is liberated into solution upon treatment with mild acid, and is concomitantly captured by an aldehyde-modified resin. This step allows the removal of the most frequently observed by-product in NCL chemistry, i.e. the hydrolysed peptide thioester (which does not contain a C-terminal peptide hydrazide). Finally, the target protein is released with diluted hydrazine or acid. We applied the method in the synthesis of 46 to 126 amino acid long MUC1 proteins comprising 2-6 copies of a 20mer tandem repeat sequence. Only three days were required for the parallel synthesis of 9 MUC1 proteins

  4. Tebuconazole photocatalytic degradation kinetics

    OpenAIRE

    Prestes, Thiago de Hermann; Gibbon, Danielle de Oliveira; Lansarin, Marla Azário; Moro, Celso Camilo

    2010-01-01

    The tebuconazole photocatalytic degradation kinetics was studied in a batch reactor using TiO2 (P25-Degussa) as catalyst and a high pressure mercury lamp. The photolysis, adsorption and irradiation effects in the reaction rate were evaluated. Afterward, the suspension catalyst concentration and initial pH to the maximum reaction rate was determined. It was observed that the reaction rate can be approached by a pseudo-first order, with a maximum kinetics constant at 260 mg L-1catalyst concentr...

  5. HPLC analysis of sesaminol glucosides in sesame seeds.

    Science.gov (United States)

    Moazzami, Ali A; Andersson, Rolf E; Kamal-Eldin, Afaf

    2006-02-08

    An HPLC method was developed and validated for the quantification of sesaminol triglucoside and a sesaminol diglucoside in sesame seeds. These two lignans were isolated, and their structures were characterized by mass and nuclear magnetic resonance spectroscopy. Defatted sesame flour was extracted first with 85% ethanol for 5 h followed by 70% ethanol for 10 h at room temperature using naringenin as internal standard. Analysis of 65 different samples of sesame seeds indicated that the content of sesaminol triglucoside ranged from 36 to 1560 mg/100 g of seed (mean 637 +/- 312) and that of sesaminol diglucoside ranged from 0 to 493 mg/100 g of seed (mean 75 +/- 95). No significant difference was found between sesaminol glucoside contents in black and white seeds.

  6. In vitro monitoring of ciprofloxacin antacids interactions by UV & HPLC.

    Science.gov (United States)

    Sultana, Najma; Arayne, M Saeed; Hussain, Fida

    2005-10-01

    Ciprofloxacin or 1-cyclopropyl-6-fluoro-1,4-dihydro-4-oxo-7-(1-piperazinyl]-3-quinoline carboxylic acid is a fluorinated quinolone antibacterial agent extensively used worldwide. There are number of drug interactions reported for this antibacterial agent. In present studies, in vitro release of ciprofloxacin hydrochloride in presence of various antacids like sodium bicarbonate, calcium hydroxide, calcium carbonate, aluminum hydroxide, magnesium hydroxide, magnesium carbonate, magnesium trisilicate and magaldrate has been studied on BP 2002 dissolution test apparatus. Drug in each case was analyzed either by measuring the absorbance of aliquots at 278 and 316 nm on a UV/VIS spectrophotometer, or by reversed-phase high-performance liquid chromatographic (RP-HPLC) method. These studies were carried out in simulated gastric and intestinal juices for three hours at 37 degrees C. The availability of ciprofloxacin was found to be markedly retarded in presence of all the antacids studied.

  7. HPLC Analysis of Colorants Migrated from Children's Modeling Clays.

    Science.gov (United States)

    Kishi, Eri; Ozaki, Asako; Ooshima, Tomoko; Yamano, Tetsuo

    2016-01-01

    A method using high-performance liquid chromatograph (HPLC) was developed for the identification of colorants migrated from colored modeling clays, which are popular toys for children. Twelve permitted dyes and 25 non-permitted dyes were analyzed in 20 clays (10 wheat clays, 2 rice clays, 2 corn clays, 3 paper clays and 3 resin clays). As a result, 13 products which were labeled for children's use (under 6 years old) met the specifications of the Japanese Food Sanitation Law, while non-permitted colorants were eluted from 2 products. In additon, unknown colorants were eluted from 3 products for people over 6 years old, although these are not covered by the Japanese regulation. It was suggested that some type of clays contained pigments, which are generally used in printing ink and plastics.

  8. Quantitative analysis of PMR-15 polyimide resin by HPLC

    Science.gov (United States)

    Roberts, Gary D.; Lauver, Richard W.

    1987-01-01

    The concentration of individual components and of total solids of 50 wt pct PMR-15 resin solutions was determined using reverse-phase HPLC to within + or - 8 percent accuracy. Acid impurities, the major source of impurities in 3,3', 4,4'-benzophenonetetracarboxylic acid (BTDE), were eliminated by recrystallizing the BTDE prior to esterification. Triester formation was not a problem because of the high rate of esterification of the anhydride relative to that of the carboxylic acid. Aging of PMR-15 resin solutions resulted in gradual formation of the mononadimide and bisnadimide of 4,4'-methylenedianiline, with the BTDE concentration remaining constant. Similar chemical reactions occurred at a reduced rate in dried films of PMR-15 resin.

  9. HPLC Determination of Polyphenols from Calendula officinalis L. Flowers

    Directory of Open Access Journals (Sweden)

    Frum Adina

    2017-12-01

    Full Text Available Romanian spontaneous flora provides a lot of resources for the determination of different chemical compounds. This study uses flower samples from Calendula officinalis L. extracted through maceration. The chemical compounds determined were: (+-catechin, caffeic acid, chlorogenic acid, cinnamic acid, ferulic acid, gallic acid, rutin, resveratrol and quercetin. They were analyzed by using an optimized HPLC method. (+-Catechin, caffeic acid, chlorogenic acid and quercetin could not be identified in the analyzed samples. The greatest amount of phenolic compound found was rutin and the smallest quantity was determined for ferulic acid. The quantified compounds have proven to have benefits regarding human health, thus they can be used as functional compounds and can be included in food products and food supplements.

  10. [HPLC fingerprint chromatogram of Polygonum multiflorum from Guizhou].

    Science.gov (United States)

    Li, Yan; Wang, Hui-Juan; Lin, Bing; Zhao, Zhi; Zhou, Ying

    2012-12-01

    To establish the fingerprint of Polygonum multiflorum from Guizhou and provide a standard for its quality control. HPLC analysis was performed on Agillent ZABAX-C18 (4.6 mm x 250 mm, 5 microm), gradient eluted composed of acetonitrile-0.4% water solution of phosphoric acid. Column temperature was set at 25 degrees C and the flow rate was 1 mL/min. The detection wavelength was 280 nm and the analysis time was 60 min. 9 common peaks were identified. The RSD of the relative retention time and the relative peak area were less than 3% in analyzing its precision, stability and repeatability of the common peaks, and the similarity of the 16 batches of sample was more than 0.9. The method is simple and reliable, and it can provide a standard and guidance for quality control of Polygonum multiflorum.

  11. An improved HPLC method for determination of colocynthin in colocynth

    Directory of Open Access Journals (Sweden)

    M. Shekarchi

    2015-10-01

    Full Text Available Background and objectives: Colocynthin is the major active secondary metabolite of colocynth, Citrullus colocynthis (L. Schrad, which has been used in traditional and ethno medicine of many countries.  It could be considered as an active marker for quality control of colocynth and its herbal products. Analysis and standardization of colocynth and its herbal preparations are a critical issue for their safe applications in phytotherapy and traditional medicine. In the present work, a simple and efficient sample preparation was developed and optimized through combination of matrix solid phase dispersion and ultrasonic assisted extraction. In addition, analytical reversed-phase HPLC method was optimized for analyzing the concentration of colocynthin in colocynth pulp. Methods: Powdered colocynth pulp was grinded with diatomaceous earth to obtain a homogenous mixture. The blend was mixed with methanol and extracted by sonication, followed by centrifugation and filtration. The analytical chromatographic separation was carried out using Luna C18 in isocratic elution with methanol: isopropanol: water: triflouroacetic acid (30:10:60:0.1 v/v. The method was validated as well.  Results: The validation parameters were determines as follows, linear range (r2 = 0.999, 75-500 μg/mL, precision (intra-day < 2.7%, inter-day = 4.4% and accuracy measured via determination of recovery (90-107%. The limit of detection and quantization were calculated 8.5 and 25.7 μg/mL, respectively. Conclusion: Regarding the relatively high content of colocynthin in colocynth pulp, the validated HPLC method could be applied for quality control of colocynth pulp used in Traditional Persian Medicine.

  12. Simple Determination of Plasma Ponatinib Concentration Using HPLC.

    Science.gov (United States)

    Yasu, Takeo; Momo, Kenji; Kobayashi, Shunsuke; Kuroda, Seiichirou; Tojo, Arinobu

    2018-02-01

    Ponatinib, a novel tyrosine kinase inhibitor marketed in 2016, is a key drug used for treating chronic myeloid leukemia and Philadelphia chromosome-positive acute lymphoblastic leukemia. This study aimed to develop a simple method for determining plasma ponatinib concentration. The analysis required extraction of a 400-µL sample of plasma and precipitation of proteins using an Oasis HLB cartridge. Ponatinib and bosutinib, which is used as an internal standard, were separated by HPLC using a mobile phase of acetonitrile : 0.037 mol/L KH2PO4 (pH 4.5) (39 : 61, v/v) on a Capcell Pack C18 MG II (25×4.6 mm) monitored at 250 nm, with a flow rate of 1.0 mL/min. This assay method was then used for determining plasma ponatinib concentration in a 42-year-old man treated with ponatinib at 15 mg/d. The calibration curve was found to be linear for the plasma concentration range of 5-250 ng/mL with a regression coefficient (r2) of 0.9999. The coefficients of intra-day and inter-day validation under these concentrations were 2.1-6.0 and 4.5-8.0%, respectively. The assay accuracy was -1.5-9.0%, and the recovery was greater than 86%. The plasma concentration of the patient at 2.5 and 3 h after 15 mg ponatinib administration was 43.6 and 49.3 ng/mL, respectively. This method of HPLC equipped with UV detection for determining plasma ponatinib concentration has several advantages, such as simplicity and applicability to routine therapeutic drug monitoring at hospital laboratories.

  13. Identification of Rhodiola species by using RP-HPLC*

    Science.gov (United States)

    Wang, Qiang; Ruan, Xiao; Jin, Zhi-hua; Yan, Qi-chuan; Tu, Shan-jun

    2005-01-01

    An approach was established using RP-HPLC (reversed-phase high-performance liquid chromatography) to identify ten species of Rhodiola, R. coccinea A. Bor, R. junggarica C.Y. Yang et N.R. Cui spn., R. heterodonta A. Bor, R. linearifolia A. Bor, R. pamiro alaiucm A. Bor, R. kaschgarica A. Bor, R. litwinowii A. Bor, R. gelida schrenk, R. rosea L. and R. quadrifide Fisch et Mey collected from the Tianshan Mountains areas of China. Chromatograms of alcohol-soluble proteins, generated from these ten Rhodiola spp. were compared. Each chromatogram of alcohol-soluble proteins came from a single seed of one wild species only. The results showed that when using a Waters Delta Pak. C18, 5 μm particle size reversed phase column (150 mm×3.9 mm), a linear gradient of 22%–55% solvent B with a flow rate of 1 ml/min and a run time of 67 min, the chromatography gave optimum separation of Rhodiola alcohol-soluble proteins. Chromatogram of each species was different and could be used to identify those species. Cluster analysis of genetic similarity coefficients of 37% to 60% showed a medium degree of genetic diversity among the species in these eco-areas. Cluster analysis showed that the ten species of Rhodiola can be divided into four clusters and yielded the general and unique biochemical markers of these species. RP-HPLC was shown to be a rapid, repeatable and reliable method for Rhodiola species identification and analysis of genetic diversity. PMID:15909330

  14. Analysis of brominated and phosphate-based flame retardants in polymer samples by HPLC-UV/MS and online-GPC-HPLC-UV

    Energy Technology Data Exchange (ETDEWEB)

    Schlummer, M.; Brandl, F. [Fraunhofer-Institut fuer Verfahrenstechnik und Verpackung (IVV), Freising (Germany); Maeurer, A.

    2004-09-15

    Here we present two analytical approaches for the identification and quantification of brominated and phosphate-based flame retardants. The first is an HPLC-UV/MS approach, which allows the separation and unequivocal identification and quantification of at least 15 different technical flame retardants. The second approach was set-up as a screening tool, consisting of a GPC separation coupled to an HPLC-UV device.

  15. Kinetic energy budget details

    Indian Academy of Sciences (India)

    Abstract. This paper presents the detailed turbulent kinetic energy budget and higher order statistics of flow behind a surface-mounted rib with and without superimposed acoustic excitation. Pattern recognition technique is used to determine the large-scale structure magnitude. It is observed that most of the turbulence ...

  16. Modeling chemical kinetics graphically

    NARCIS (Netherlands)

    Heck, A.

    2012-01-01

    In literature on chemistry education it has often been suggested that students, at high school level and beyond, can benefit in their studies of chemical kinetics from computer supported activities. Use of system dynamics modeling software is one of the suggested quantitative approaches that could

  17. SHORT COMMUNICATION KINETIC SPECTROPHOTOMETRIC ...

    African Journals Online (AJOL)

    Preferred Customer

    ABSTRACT. ABSTRACT. A novel catalytic kinetic spectrophotometric method for the determination of iron is developed based on the catalytic effect of Fe(III) on the oxidation reaction of p-acetylarsenazo(ASApA) by potassium periodate. Maximum absorbance of the Fe(III)-ASApA-KIO4 system in 8.0 × 10-3 M sulfuric acid ...

  18. CATALYTIC KINETIC SPECTROPHOTOMETRIC DETERMINATION ...

    African Journals Online (AJOL)

    Based on the property that in 0.12 M sulfuric acid medium titanium(IV) catalyzes the discoloring reaction of DBS-arsenazo oxidized by potassium bromate, a new catalytic kinetic spectrophotometric method for the determination of trace titanium (IV) was developed. The linear range of the determination of titanium is

  19. CATALYTIC KINETIC SPECTROPHOTOMETRIC DETERMINATION ...

    African Journals Online (AJOL)

    Preferred Customer

    Research Center for Nanotechnology, Changchun University of Science and Technology,. Changchun 130022 ... Although catalytic kinetic spectrophotometry has been used in the determination of copper, the selectivity ... In this paper CPApA was used as the chromogenic agent, H2O2 as the oxidant, Cu(II) as the catalyst.

  20. Chemical Profiling (HPLC-NMR & HPLC-MS, Isolation, and Identification of Bioactive Meroditerpenoids from the Southern Australian Marine Brown Alga Sargassum paradoxum

    Directory of Open Access Journals (Sweden)

    Robert Brkljača

    2014-12-01

    Full Text Available A phytochemical investigation of a southern Australian marine brown alga, Sargassum paradoxum, resulted in the isolation and identification of four new (5, 9, 10, and 15 and nine previously reported (1, 2, 6–8, and 11–14 bioactive meroditerpenoids. HPLC-NMR and HPLC-MS were central to the identification of a new unstable compound, sargahydroquinal (9, and pivotal in the deconvolution of eight (1, 2, 5–7, and 10–12 other meroditerpenoids. In particular, the complete characterization and identification of the two main constituents (1 and 2 in the crude dichloromethane extract was achieved using stop-flow HPLC-NMR and HPLC-MS. This study resulted in the first acquisition of gHMBCAD NMR spectra in the stop-flow HPLC-NMR mode for a system solely equipped with a 60 μL HPLC-NMR flow cell without the use of a cold probe, microcoil, or any pre-concentration.

  1. Development and Validation of a New RP-HPLC Method for the ...

    African Journals Online (AJOL)

    ... rapid, cost-effective and accurate reverse phase-high performance liquid chromatography (RP-HPLC) method for the determination of aprepitant (APT) in capsule dosage form. Methods: The method developed for the determination of APT in capsule formulation involved using RP-HPLC which incorporated a C18 column ...

  2. Development and Validation of a RP-HPLC Method for the ...

    African Journals Online (AJOL)

    Erah

    Abstract. Purpose: To develop and validate a sensitive HPLC method for the separation and simultaneous estimation of two ... Methods: Reverse phase (RP) chromatographic separation and estimation was achieved using a. Shimadzu HPLC system. ..... 2.26, and r2, >0.999; CC-I: slope, 0.00046, y- intercept, 0.24351, and ...

  3. Theoretische en practische aspecten van het gebruik van micro-HPLC

    NARCIS (Netherlands)

    de Fluiter P; Jansen EHJM

    1992-01-01

    A practical and theoretical approach for the implementation of micro high performance liquid chromatography (HPLC) is described. A new simple and rapid test procedure was developed in wich a HPLC system can be validated for its suitability for micro-bore columns. It appeared that the detector

  4. Size exclusion HPLC of proteins for evaluation of durum wheat quality

    Science.gov (United States)

    The present research aimed to assess size exclusion HPLC (SE-HPLC) in protein molecular weight distribution determination for quality evaluation of durum semolina. Semolina samples were milled from 13 durum genotypes grown at 7 locations in 2009 and 2010 in ND. Sodium dodecyl sulfate (SDS) buffer ...

  5. Learning Chemical Kinetics with Spreadsheets.

    Science.gov (United States)

    Blickensderfer, Roger

    1990-01-01

    Presented are several simple kinetic systems together with the spreadsheets used to solve them. A set of exercises in chemical kinetics appropriate for an introductory course in physical chemistry is given. Error propagation calculations with experimental data are illustrated. (CW)

  6. Propanil in a Manitoba soil: an interactive spreadsheet model based on conventional chemical kinetics.

    Science.gov (United States)

    Gamble, Donald S; Webster, G R Barrie; Lamoureux, Marc

    2012-04-01

    An interactive spreadsheet model has been created for quantitative predictions of propanil sorption and reaction in a slurried Manitoba clay soil. Based on experimental values for the numbers of empty and filled sorption sites as reactants and products, the reaction mechanism has been described with conventional chemical kinetics. The on line HPLC μ extraction method revealed labile sorption, intraparticle diffusion, and a chemical reaction. Laidler's integral rate law for second order kinetics describes the labile sorption. Desorption, intraparticle diffusion, and the chemical reaction are all described by first order kinetics. The time dependent effects of initial concentration and amount of slurried soil can be predicted for sorption, intraparticle diffusion, and the amount of reaction product. Suggested applications include storm runoff and inputs for fate and transport hydrology models.

  7. Photon kinetics in plasmas

    Directory of Open Access Journals (Sweden)

    V.G. Morozov

    2009-01-01

    Full Text Available We present a kinetic theory of radiative processes in many-component plasmas with relativistic electrons and nonrelativistic heavy particles. Using the non-equilibrium Green's function technique in many-particle QED, we show that the transverse field correlation functions can be naturally decomposed into sharply peaked (non-Lorentzian parts that describe resonant (propagating photons and off-shell parts corresponding to virtual photons in the medium. Analogous decompositions are obtained for the longitudinal field correlation functions and the correlation functions of relativistic electrons. We derive a kinetic equation for the resonant photons with a finite spectral width and show that the off-shell parts of the particle and field correlation functions are essential to calculate the local radiating power in plasmas and recover the results of vacuum QED. The plasma effects on radiative processes are discussed.

  8. Kinetics of phase change

    Directory of Open Access Journals (Sweden)

    A.C. Faleiros

    2000-07-01

    Full Text Available The kinetic model for change of phases developed by M. Avrami at the end of the thirties has been used to describe the temporal behavior of phase changes. Until today this model is studied and adapted to include broader hypotheses. However, the mathematical format presented by M. Avrami is difficult to be understood by beginners. The purpose of this work is to clarify the mathematical treatment of Avrami's work, going straightforward to the arguments that led to his main results.

  9. Kinetic transport in crystals

    OpenAIRE

    Marklof, Jens

    2009-01-01

    One of the central challenges in kinetic theory is the derivation of macroscopic evolution equations--describing, for example, the dynamics of an electron gas--from the underlying fundamental microscopic laws of classical or quantum mechanics. An iconic mathematical model in this research area is the Lorentz gas, which describes an ensemble of non-interacting point particles in an infinite array of spherical scatterers. In the case of a disordered scatterer configuration, the classical result...

  10. Adsorption Kinetics at Silica Gel/Ionic Liquid Solution Interface

    Directory of Open Access Journals (Sweden)

    Jolanta Flieger

    2015-12-01

    Full Text Available A series of imidazolium and pyridinium ionic liquids with different anions (Cl−, Br−, BF4−, PF6− has been evaluated for their adsorption activity on silica gel. Quantification of the ionic liquids has been performed by the use of RP-HPLC with organic-aqueous eluents containing an acidic buffer and a chaotropic salt. Pseudo-second order kinetic models were applied to the experimental data in order to investigate the kinetics of the adsorption process. The experimental data showed good fitting with this model, confirmed by considerably high correlation coefficients. The adsorption kinetic parameters were determined and analyzed. The relative error between the calculated and experimental amount of ionic liquid adsorbed at equilibrium was within 7%. The effect of various factors such as initial ionic liquid concentration, temperature, kind of solvent, kind of ionic liquid anion and cation on adsorption efficiency were all examined in a lab-scale study. Consequently, silica gel showed better adsorptive characteristics for imidazolium-based ionic liquids with chaotropic anions from aqueous solutions in comparison to pyridinium ionic liquids. The adsorption was found to decrease with the addition of organic solvents (methanol, acetonitrile but it was not sensitive to the change of temperature in the range of 5–40 °C.

  11. Content determination of obeticholic acid tablets by HPLC

    Directory of Open Access Journals (Sweden)

    Yunxia LU

    2017-04-01

    Full Text Available In order to establish a method for the content determination of obeticholic acid tablets, HPLC-UV method is adopted. The determination is performed on Agilent HC-C18 column(250 mm×4.6 mm,5 μm) with mobile phase acetonitrile (002% formic acid-water (0.02% formic acid = 60∶40 (V/V at the flow rate of 1.0 mL/min. The detection wavelength is 195 nm, the column temperature is 30 ℃ and the volume is 100 μL. The result shows that there is a good liner relationship between the mass concentration of obeticholic acid in the range of 0.200 26~1.001 30 mg/mL and the peak area, and r=0.999 9. The RSD of precision, stability and reproducible tests are all less than 1.0%. The average recovery rate is 99.64% , and RSD is 0.58%(n=9. The method is simple, exclusive, accurate and durable, and can be used for the content determination of obeticholic acid tablets.

  12. A new HPLC method for pidotimod plasma levels determination.

    Science.gov (United States)

    Dal Bo, L; Broccali, G P; Silingardi, S; Coppi, G

    1993-04-01

    This paper describes a HPLC method for the determination of Pidotimod (3-L-pyroglutamyl-L-thiazolidine-4-carboxylic acid; PGT/1A), a new biological response modifier, in plasma. The column was an Aminex Ion Exclusion HPX 874 with a PRP precolumn, the mobile phase was 0.05% sulfuric acid-acetonitrile (88:12, v/v), the flow rate was 0.6 ml/min, the detection wavelength was 210 nm. Plasma (1 ml) was added with internal standard (Oxiracetam, concentration 400 micrograms/ml) (50 microliters) and 35% perchloric acid (100 microliters). The supernatant (0.5 ml) was added with mobile phase (0.5 ml) and, after centrifugation, injected into the column. The retention times of Pidotimod and Oxiracetam were 16.5 and 13.8 min. respectively. The method was validated for recovery, accuracy and reproducibility. The results after oral administration of 800 mg of Pidotimod in male volunteers were also given. This method is better than that previously described because it utilizes an internal standard and reaches a lower detection limit.

  13. HPLC-ELSD analysis of spectinomycin dihydrochloride and its impurities.

    Science.gov (United States)

    Zhou, Junyi; Zhang, Lin; Wang, Yan; Yan, Chao

    2011-08-01

    A simple, rapid and reliable reversed-phase ion-pair chromatography method by HPLC coupled to an evaporative light scattering detector (ELSD) has been developed to simultaneously determine chloride, spectinomycin and its related substances in a sample. The column was a TSKgel ODS-100V. The mobile phase was ACN/aqueous solution of 15 mM ammonium acetate adjusted with TFA to pH 3.0 (2:98 v/v), in an isocratic mode. The drift tube temperature was set at 50°C and the nebulizing gas flow rate of air was 3.5 L/min for ELSD detection. Almost all of the reported degradation compounds of spectinomycin such as actinamine, actinospectinoic acid and biosynthesis intermediates such as dihydrospectinomycin diastereoisomers were baseline separated. MS was utilized for the identification of spectinomycin and its seven related substances. The method for the assay of spectinomycin was successfully validated with respect to accuracy, precision (RSD less than 2%), linearity (throughout the linear range 0.025-3 mg/mL, r=0.9993), sensitivity (LOD: 100 ng on column) and robustness. The experimental results demonstrated that the simultaneous determination of chloride, spectinomycin and related substances is feasible in a single run, which suggests applicability in routine assays. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. HPLC analysis of methylxanthines in human breast milk.

    Science.gov (United States)

    Blanchard, J; Weber, C W; Shearer, L E

    1990-12-01

    A sensitive and specific high-performance liquid chromatographic (HPLC) procedure is developed for simultaneously quantitating the levels of caffeine, theophylline, theobromine and paraxanthine in breast milk. The method involved the precipitation of proteins present in the milk samples with a 6% v/v perchloric acid solution containing the internal standard, proxyphylline, followed by centrifugation at 12,800 Xg for 10 minutes. The clear supernatant was then chromatographed on a C18 reversed-phase analytical column at ambient temperature using a wavelength of 272 nm. Samples were eluted from the column at a constant flow rate of 1.5 mL/min using a gradient program in which the concentration of methanol in the mobile phase varied from 0 to 16%. The mean recoveries of the methylxanthines averaged over all the concentrations examined were generally excellent and ranged from 96.3 +/- 5.4% for caffeine to 102.3 +/- 8.9% for paraxanthine. The assay precision was very good and the peaks of interest were extremely well resolved. The method is recommended for assessing the total caffeine and dimethylxanthine load to which the nursing infant is exposed in mothers ingesting typical amounts of caffeine.

  15. HPLC retention thermodynamics of grape and wine tannins.

    Science.gov (United States)

    Barak, Jennifer A; Kennedy, James A

    2013-05-08

    The effect of grape and wine tannin structure on retention thermodynamics under reversed-phase high-performance liquid chromatography conditions on a polystyrene divinylbenzene column was investigated. On the basis of retention response to temperature, an alternative retention factor was developed to approximate the combined temperature response of the complex, unresolvable tannin mixture. This alternative retention factor was based upon relative tannin peak areas separated by an abrupt change in solvent gradient. Using this alternative retention factor, retention thermodynamics were calculated. Van't Hoff relationships of the natural log of the alternative retention factor against temperature followed Kirchoff's relationship. An inverse quadratic equation was fit to the data, and from this the thermodynamic parameters for tannin retention were calculated. All tannin fractions exhibited exothermic, spontaneous interaction, with enthalpy-entropy compensation observed. Normalizing for tannin size, distinct tannin compositional effects on thermodynamic parameters were observed. The results of this study indicate that HPLC can be valuable for measuring the thermodynamics of tannin interaction with a hydrophobic surface and provides a potentially valuable alternative to calorimetry. Furthermore, the information gathered may provide insight into understanding red wine astringency quality.

  16. Calcite Dissolution Kinetics

    Science.gov (United States)

    Berelson, W.; Subhas, A.; Dong, S.; Naviaux, J.; Adkins, J. F.

    2016-12-01

    A geological buffer for high atmospheric CO2 concentrations is neutralization via reaction with CaCO3. We have been studying the dissolution kinetics of carbonate minerals using labeled 13C calcite and Picarro-based measurements of 13C enrichments in solution DIC. This methodology has greatly facilitated our investigation of dissolution kinetics as a function of water carbonate chemistry, temperature and pressure. One can adjust the saturation state Omega by changing the ion activity product (e.g. adjusting carbonate ion concentration), or by changing the solubility product (e.g. adjusting temperature or pressure). The canonical formulation of dissolution rate vs. omega has been refined (Subhas et al. 2015) and shows distinct non-linear behavior near equilibrium and rates in sea water of 1-3 e-6 g/cm2day at omega = 0.8. Carbonic anhydrase (CA), an enzyme that catalyzes the hydration of dissolved CO2 to carbonic acid, was shown (in concentrations rate at low degrees of undersaturation by >500x. This result points to the importance of carbonic acid in enhancing dissolution at low degrees of undersaturation. CA activity and abundance in nature must be considered regarding the role it plays in catalyzing dissolution. We also have been investigating the role of temperature on dissolution kinetics. An increase of 16C yields an order of magnitude increase in dissolution rate. Temperature (and P) also change Omega critical, the saturation state where dissolution rates change substantially. Increasing pressure (achieved in a pressure reaction chamber we built) also shifts Omega critical closer to equilibrium and small pressure increases have large impact on dissolution kinetics. Dissolution rates are enhanced by an order of magnitude for a change in pressure of 1500 psi relative to the dissolution rate achieved by water chemistry effects alone for an omega of 0.8. We've shown that the thermodynamic determination of saturation state does not adequately describe the kinetics

  17. Applications of HPLC/MS in the analysis of traditional Chinese medicines

    Science.gov (United States)

    Li, Miao; Hou, Xiao-Fang; Zhang, Jie; Wang, Si-Cen; Fu, Qiang; He, Lang-Chong

    2012-01-01

    In China, traditional Chinese medicines (TCMs) have been used in clinical applications for thousands of years. The successful hyphenation of high-Performance liquid chromatography (HPLC) and mass spectrometry (MS) has been applied widely in TCMs and biological samples analysis. Undoubtedly, HPLC/MS technique has facilitated the understanding of the treatment mechanism of TCMs. We reviewed more than 350 published papers within the last 5 years on HPLC/MS in the analysis of TCMs. The present review focused on the applications of HPLC/MS in the component analysis, metabolites analysis, and pharmacokinetics of TCMs etc. 50% of the literature is related to the component analysis of TCMs, which show that this field is the most populär type of research. In the metabolites analysis, HPLC coupled with electrospray ionization quadrupole time-of-flight tandem mass spectrometry has been demonstrated to be the powerful tool for the characterization of structural features and fragmentation behavior patterns. This paper presented a brief overview of the applications of HPLC/MS in the analysis of TCMs. HPLC/MS in the fingerprint analysis is reviewed elsewhere. PMID:29403684

  18. Mass transfer kinetics, band broadening and column efficiency.

    Science.gov (United States)

    Gritti, Fabrice; Guiochon, Georges

    2012-01-20

    Important progress was recently made in our understanding of the physico-chemical aspects of mass transfer kinetics in chromatographic columns, in methods used for accurate determination of the different contributions to the height equivalent to a theoretical plate (HETP), and in the application of these advances to the elucidation of mass transfer mechanisms in columns packed with recent chromatographic supports (sub-2 μm fully porous particles, sub-3 μm core-shell particles, and monoliths). The independent contributions to the HETP are longitudinal diffusion, eddy dispersion, liquid-solid mass transfer (including trans-particle or trans-skeleton mass transfer and external film mass transfer), and the contributions caused by the thermal heterogeneity of the column. The origin and importance of these contributions are investigated in depth. This work underlines the areas in which improvements are needed, an understanding of the contribution of the external film mass transfer term, a better design of HPLC instruments providing a decrease of the extra-column band broadening contributions to the apparent HETP, the development of better packing procedures giving more radially homogeneous column beds, and new packing materials having a higher thermal conductivity to eliminate the nefarious impact of heat effects in very high pressure liquid chromatography (vHPLC) and supercritical fluid chromatography (SFC). Copyright © 2011 Elsevier B.V. All rights reserved.

  19. HPLC determination of glutathione and L-cysteine in pharmaceuticals after derivatization with ethacrynic acid.

    Science.gov (United States)

    Di Pietra, A M; Gotti, R; Bonazzi, D; Andrisano, V; Cavrini, V

    1994-01-01

    Ethacrynic acid and its methyl ester are proposed as useful pre-chromatographic derivatization reagents for the HPLC analysis (UV detection) of reduced glutathione (GSH) and L-cysteine. The optimum experimental conditions for the thiol derivatization, the removal of the excess reagent by liquid-liquid or solid-phase extraction and the reversed-phase chromatographic separations of the thiol adducts were investigated. The method was applied to the HPLC determination of GSH and L-cysteine in commercial formulations and proved to be suitable for the HPLC determination of oxidized glutathione (GSSG) after reduction to GSH using dithiothreitol (DTT).

  20. Electrochemically Pretreated Carbon Microfiber Electrodes as Sensitive HPLC-EC Detectors

    Directory of Open Access Journals (Sweden)

    Zdenka Bartosova

    2012-01-01

    Full Text Available The paper focuses on the analysis and detection of electroactive compounds using high-performance liquid chromatography (HPLC combined with electrochemical detection (EC. The fabrication and utilization of electrochemically treated carbon fiber microelectrodes (CFMs as highly sensitive amperometric detectors in HPLC are described. The applied pretreatment procedure is beneficial for analytical characteristics of the sensor as demonstrated by analysis of the model set of phenolic acids. The combination of CFM with separation power of HPLC technique allows for improved detection limits due to unique electrochemical properties of carbon fibers. The CFM proved to be a promising tool for amperometric detection in liquid chromatography.

  1. Kinetic distance and kinetic maps from molecular dynamics simulation

    CERN Document Server

    Noe, Frank

    2015-01-01

    Characterizing macromolecular kinetics from molecular dynamics (MD) simulations requires a distance metric that can distinguish slowly-interconverting states. Here we build upon diffusion map theory and define a kinetic distance for irreducible Markov processes that quantifies how slowly molecular conformations interconvert. The kinetic distance can be computed given a model that approximates the eigenvalues and eigenvectors (reaction coordinates) of the MD Markov operator. Here we employ the time-lagged independent component analysis (TICA). The TICA components can be scaled to provide a kinetic map in which the Euclidean distance corresponds to the kinetic distance. As a result, the question of how many TICA dimensions should be kept in a dimensionality reduction approach becomes obsolete, and one parameter less needs to be specified in the kinetic model construction. We demonstrate the approach using TICA and Markov state model (MSM) analyses for illustrative models, protein conformation dynamics in bovine...

  2. Kinetics of tetrataenite disordering

    Energy Technology Data Exchange (ETDEWEB)

    Dos Santos, E., E-mail: edisanfi@cbpf.br [Centro Brasileiro de Pesquisas Físicas, Rio de Janeiro (Brazil); Gattacceca, J.; Rochette, P. [Centre Européen de Recherche et d’Enseignement des Géosciences de l’Environnement, UM34, CNRS/Aix-Marseille University, Aix-en-Provence (France); Fillion, G. [Laboratoire National des Champs Magnétiques Intenses (LNCMI), CNRS, UJF, 38042 Grenoble (France); Scorzelli, R.B. [Centro Brasileiro de Pesquisas Físicas, Rio de Janeiro (Brazil)

    2015-02-01

    Tetrataenite is a chemically ordered L1{sub 0}-type Fe{sub 50}Ni{sub 50} alloy detected for the first time in 1977 by {sup 57}Fe Mössbauer spectroscopy studies in iron meteorites. The thermal history of meteorites, in particular short thermal events like those associated to hypervelocity impacts, can be constrained by tracing the presence of tetrataenite or its disordering into taenite. The knowledge of the disordering kinetics of tetrataenite, that is associated with changes in its magnetic properties, is still very fragmentary so that the time–temperature history of these meteorites cannot be constrained in details. Furthermore, knowledge of disordering kinetics is important due to potential technological application of tetrataenite as a rare-earth free strong magnet. Thus, this work provides the first time–temperature data for disordering reaction of tetrataenite. We have shown that disordering is not an instantaneous process but is a kinetic limited reaction. It was shown that disordering may take place at any temperature above the order–disorder transition for L{sub 10} superstructure phase (∼320 °C) when the appropriate time-scale is considered. This result means that the apparent Curie point for tetrataenite is not an absolute property in the sense that any estimate of this parameter should be referred to a given time-scale. - Highlights: • The first time–temperature data for tetrataenite disordering reaction is provided. • Previous works does not give a complete picture of tetrataenite disordering. • Apparent Curie temperature of tetrataenite should be referred to a time-scale. • Tetrataenite can be used as a probe to detect thermal/shock events recorded in meteorites.

  3. Kinetics of stress fibers

    Energy Technology Data Exchange (ETDEWEB)

    Stachowiak, Matthew R; O' Shaughnessy, Ben [Department of Chemical Engineering, Columbia University, New York, NY 10027 (United States)], E-mail: bo8@columbia.edu

    2008-02-15

    Stress fibers are contractile cytoskeletal structures, tensile actomyosin bundles which allow sensing and production of force, provide cells with adjustable rigidity and participate in various processes such as wound healing. The stress fiber is possibly the best characterized and most accessible multiprotein cellular contractile machine. Here we develop a quantitative model of the structure and relaxation kinetics of stress fibers. The principal experimentally known features are incorporated. The fiber has a periodic sarcomeric structure similar to muscle fibers with myosin motor proteins exerting contractile force by pulling on actin filaments. In addition the fiber contains the giant spring-like protein titin. Actin is continuously renewed by exchange with the cytosol leading to a turnover time of several minutes. In order that steady state be possible, turnover must be regulated. Our model invokes simple turnover and regulation mechanisms: actin association and dissociation occur at filament ends, while actin filament overlap above a certain threshold in the myosin-containing regions augments depolymerization rates. We use the model to study stress fiber relaxation kinetics after stimulation, as observed in a recent experimental study where some fiber regions were contractile and others expansive. We find that two distinct episodes ensue after stimulation: the turnover-overlap system relaxes rapidly in seconds, followed by the slow relaxation of sarcomere lengths in minutes. For parameter values as they have been characterized experimentally, we find the long time relaxation of sarcomere length is set by the rate at which actin filaments can grow or shrink in response to the forces exerted by the elastic and contractile elements. Consequently, the stress fiber relaxation time scales inversely with both titin spring constant and the intrinsic actin turnover rate. The model's predicted sarcomere velocities and contraction-expansion kinetics are in good

  4. Chemical kinetics modeling

    Energy Technology Data Exchange (ETDEWEB)

    Westbrook, C.K.; Pitz, W.J. [Lawrence Livermore National Laboratory, CA (United States)

    1993-12-01

    This project emphasizes numerical modeling of chemical kinetics of combustion, including applications in both practical combustion systems and in controlled laboratory experiments. Elementary reaction rate parameters are combined into mechanisms which then describe the overall reaction of the fuels being studied. Detailed sensitivity analyses are used to identify those reaction rates and product species distributions to which the results are most sensitive and therefore warrant the greatest attention from other experimental and theoretical research programs. Experimental data from a variety of environments are combined together to validate the reaction mechanisms, including results from laminar flames, shock tubes, flow systems, detonations, and even internal combustion engines.

  5. Analysis of sesquiterpene lactones, lignans, and flavonoids in wormwood (Artemisia absinthium L.) using high-performance liquid chromatography (HPLC)-mass spectrometry, reversed phase HPLC, and HPLC-solid phase extraction-nuclear magnetic resonance.

    Science.gov (United States)

    Aberham, Anita; Cicek, Serhat Sezai; Schneider, Peter; Stuppner, Hermann

    2010-10-27

    Today, the medicinal use of wormwood (Artemisia absinthium) is enjoying a resurgence of popularity. This study presents a specific and validated high-performance liquid chromatography (HPLC)-diode array detection method for the simultaneous determination and quantification of bioactive compounds in wormwood and commercial preparations thereof. Five sesquiterpene lactones, two lignans, and a polymethoxylated flavonoid were baseline separated on RP-18 material, using a solvent gradient consisting of 0.085% (v/v) o-phosphoric acid and acetonitrile. The flow rate was 1.0 mL/min, and chromatograms were recorded at 205 nm. The stability of absinthin was tested exposing samples to light, moisture, and different temperatures. Methanolic and aqueous solutions of absinthin were found to be stable for up to 6 months. This was also the case when the solid compound was kept in the refrigerator at -35 °C. In contrast, the colorless needles, when stored at room temperature, turned yellow. Three degradation compounds (anabsin, anabsinthin, and the new dimer 3'-hydroxyanabsinthin) were identified by HPLC-mass spectrometry and HPLC-solid-phase extraction-nuclear magnetic resonance and quantified by the established HPLC method.

  6. [Determination of theacrine in rat plasma by RP-HPLC].

    Science.gov (United States)

    Zhang, Wei-Ku; Xu, Jie-Kun; Hu, Jie-Qing; Wang, Su-Bo; Li, Ping; Hiroshi, Kurihara; Yao, Xin-Sheng; Tang, Bing-Hua

    2013-03-01

    To establish a method for the determination of theacrine in rat plasma after ig. administration of theacrine. Blood sample was taken timely from the eyes canthus of rats. Plasma was isolated and the protein was precipitated by ethyl acetate. Then the plasma concentration of theacrine was determined with RP-HPLC. Caffeine was used as the internal standard. The chromatographic conditions were as follows: Phenomenex Luna C18 (4.6 mm x 250 mm, 5 microm) at 25 degrees C, a mixture of methanol-water (25: 75) as the mobile phase, at the flow rate of 1.0 mL x min(-1) and the detection wavelength of 290 nm. The linear range of theacrine was 0.5-100 mg x L(-1) (R2 = 0.998 9). The lower limit of quantification was 0.5 mg x L(-1). The intra-day RSD was 1.49% 4.40% and inter-day RSD was 0.80% -10.27%. The average extraction recoveries of theacrine were 90.3% -95.8% at concentrations of 0.5, 5.0, 50 mg x L(-1). The main pharmacokinetic parameters after ig. administration of theacrine at concentration of 30 mg x kg(-1) were as follow: C(max) (35.45 +/- 30 2.68) mg x L(-1), t(max) (0.51 +/- 0.13) h, t1/2 (3.13 +/- 1.37) h, AUC(0-infinity) (2.65.39 +/- 94.71) mg x L(-1) x h. The method has been confirmed to be simple, stable, reproducible and with high specificity, and can be used for the pharmacokinetic study of theacrine in rats.

  7. Isolation and structure elucidation of cyclopeptide alkaloids from Ziziphus nummularia and Ziziphus spina-christi by HPLC-DAD-MS and HPLC-PDA-(HRMS)-SPE-NMR.

    Science.gov (United States)

    Tuenter, Emmy; Foubert, Kenn; Staerk, Dan; Apers, Sandra; Pieters, Luc

    2017-06-01

    Seven cyclopeptide alkaloids were isolated from the stem bark of Ziziphus nummularia and Ziziphus spina-christi. Three previously undescribed compounds were identified: nummularine-U, spinanine-B and spinanine-C, together with the known compounds mauritine-F, nummularine-D, nummularine-E and amphibine-D. For their purification either semi-preparative HPLC with DAD and ESIMS detection or HPLC-PDA-(HRMS)-SPE-NMR was applied, together with conventional separation methods. Their structures were elucidated by spectroscopic means. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Residue analysis of spectinomycin in tissues of chicken and swine by HPLC

    National Research Council Canada - National Science Library

    Hamamoto, Kouko; Mizuno, Yasuharu; Koike, Ryoji; Yamaoka, Ryozo; Takahashi, Toshio; Takahashi, Yoshiyuki

    2003-01-01

    A reversed-phase HPLC method with ultraviolet detection using p-nitrophenyl hydrazine as a pre-column derivatizing reagent was investigated for the determination of the antibiotic spectinomycin (SPCM...

  9. HPLC SEPARATION OF CHIRAL ORGANOPHOSPHORUS PESTICIDES ON POLYSACCHARIDE CHIRAL STATIONARY PHASES

    Science.gov (United States)

    High-performance liquid chromatographic separation of the individual enantiomers of 12 organophosphorus pesticides (OPs) were obtained on polysaccharide chiral HPLC columns using an alkane-alcohol mobile phase. The OP pesticides were crotoxyphos, dialifor, dyfonate, fenamiphos, ...

  10. Determination of blood urea using cation exchange column solid phase extraction combined with HPLC

    National Research Council Canada - National Science Library

    Hideharu SHINTANI; Takashi INOUE

    1994-01-01

    ...°C with detection at 200 nm. By comparing ultrafiltrated blood urea and native blood urea, the blood urea from the HPLC chromatogram was found to be completely free of blood admixtures and almost free of blood protein...

  11. Single-Injection HPLC Method for Rapid Analysis of a Combination Drug Delivery System

    National Research Council Canada - National Science Library

    Tucker, Robert M; Parcher, Benjamin W; Jones, Ella F; Desai, Tejal A

    2012-01-01

    .... We present a single-step method for quantifying three model therapeutics released from a model hydrogel scaffold using high-performance liquid chromatography (HPLC). Poly(ethylene glycol) dimethacrylate (PEGDMA...

  12. Quantitative analysis by HPLC-MS2 of the pyrrolizidine alkaloid adonifoline in Senecio scandens.

    Science.gov (United States)

    Zhang, Fang; Wang, Chang-Hong; Wang, Wan; Chen, Lu-Xin; Ma, Hong-Yan; Zhang, Chao-Feng; Zhang, Mian; Bligh, S W Annie; Wang, Zheng-Tao

    2008-01-01

    A quantitative method using HPLC-MS(2) has been developed for the determination of adonifoline, one of the retronecine-type hepatotoxic pyrrolizidine alkaloids in Senecio scandens Buch.-Ham. ex D. Don., a traditional Chinese herb. Using an orthogonal design test, a simple and rapid sample extraction method was developed. HPLC analysis was conducted using a C(18) column as stationary phase and a mixture of acetonitrile and aqueous formic acid as mobile phase. Good linearity for adonifoline was found in the concentration range 0.12-4.18 microg/mL, and the HPLC-MS/MS method was shown to be appropriate, in terms of sensitivity, precision and reproducibility. The quantities of adonifoline in extracts of 18 plant samples from different collection sources and from different parts (flowers, leaves, thick stems, slim stems and roots) of S. scandens were determined using the newly developed HPLC/MS(2) analysis. (c) 2007 John Wiley & Sons, Ltd.

  13. The Validation of Plasma Darunavir Concentrations Determined by the HPLC Method for Protease Inhibitors

    National Research Council Canada - National Science Library

    Takahashi, Masaaki; Kudaka, Yuichi; Okumura, Naoya; Hirano, Atsushi; Banno, Kazuhide; Kaneda, Tsuguhiro

    2007-01-01

    .... The aim of this study was to validate the determination of plasma DRV concentrations using the HPLC method, a simple procedure for simultaneous determination of seven HIV protease inhibitors and efavirenz...

  14. Automated precolumn derivatization procedures in HPLC for biomedical and clinical applications

    NARCIS (Netherlands)

    Wolf, Johannes Hendrik

    1992-01-01

    This thesis describes three automated precolumn derivatization procedures for the analysis of carboxylic group-containing compounds. After derivatization with a suitable label, the derivatives are separated on reversed-phashed HPLC and detected by fluorescence. ... Zie: Summary

  15. Kinetics of coal pyrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Seery, D.J.; Freihaut, J.D.; Proscia, W.M. (United Technologies Research Center, East Hartford, CT (USA)); Howard, J.B.; Peters, W.; Hsu, J.; Hajaligol, M.; Sarofim, A. (Massachusetts Inst. of Tech., Cambridge, MA (USA)); Jenkins, R.; Mallin, J.; Espindola-Merin, B. (Pennsylvania State Univ., University Park, PA (USA)); Essenhigh, R.; Misra, M.K. (Ohio State Univ., Columbus, OH (USA))

    1989-07-01

    This report contains results of a coordinated, multi-laboratory investigation of coal devolatilization. Data is reported pertaining to the devolatilization for bituminous coals over three orders of magnitude in apparent heating rate (100 to 100,000 + {degree}C/sec), over two orders of magnitude in particle size (20 to 700 microns), final particle temperatures from 400 to 1600{degree}C, heat transfer modes ranging from convection to radiative, ambient pressure ranging from near vacuum to one atmosphere pressure. The heat transfer characteristics of the reactors are reported in detail. It is assumed the experimental results are to form the basis of a devolatilization data base. Empirical rate expressions are developed for each phase of devolatilization which, when coupled to an awareness of the heat transfer rate potential of a particular devolatilization reactor, indicate the kinetics emphasized by a particular system reactor plus coal sample. The analysis indicates the particular phase of devolatilization that will be emphasized by a particular reactor type and, thereby, the kinetic expressions appropriate to that devolatilization system. Engineering rate expressions are developed from the empirical rate expressions in the context of a fundamental understanding of coal devolatilization developed in the course of the investigation. 164 refs., 223 figs., 44 tabs.

  16. Chemical kinetics of gas reactions

    CERN Document Server

    Kondrat'Ev, V N

    2013-01-01

    Chemical Kinetics of Gas Reactions explores the advances in gas kinetics and thermal, photochemical, electrical discharge, and radiation chemical reactions. This book is composed of 10 chapters, and begins with the presentation of general kinetic rules for simple and complex chemical reactions. The next chapters deal with the experimental methods for evaluating chemical reaction mechanisms and some theories of elementary chemical processes. These topics are followed by discussions on certain class of chemical reactions, including unimolecular, bimolecular, and termolecular reactions. The rema

  17. Assessment by HPLC of the degradation behavior of acitretin under hydrolytic, oxidative, photolytic and thermal stress conditions

    Directory of Open Access Journals (Sweden)

    Pawan K. Porwal

    2014-12-01

    Full Text Available Acitretin is a photosensitive oral retinoid with very limited data available on its degradation. The official HPLC method for acitretin determination was insufficient to resolve the degradation products generated during stability studies. Therefore, an isocratic RP-HPLC–UV method was developed for the determination of acitretin in the presence of its related impurities and degradation products. Efficient chromatographic separation was achieved on a Thermo beta-basic column C18 (100 mm×4.6 mm, 5 μm with mobile phase containing 0.3% (v/v glacial acetic acid with acetonitrile (ACN and isopropyl alcohol (IPA in an isocratic ratio of 70:30 at a flow rate of 1.0 mL/min with the eluent monitored at 360 nm. The method was validated for specificity, linearity, precision, accuracy and robustness. The calibration plot was linear over the concentration range of 50–150 μg/mL with a correlation coefficient (r2 of 0.999. The proposed method was used to investigate the degradation kinetics of acitretin under the different degradative conditions. The degradation rate constant (K, half-life (t1/2, and t90 were calculated. Degradation of acitretin followed pseudo-first-order kinetics. The drug was found to be less stable under acidic and photolytic degradation conditions: the photolytic degradation constants for acitretin in sunlight and UV light were 0.002698% and 0.0008402% min−1, respectively. The LOD for acitretin and the known impurities were at a level below 0.02%. The method shows consistent recoveries for ACTR (99.8%–101.2% and also for its known impurities (97.2–101.3%. The method was found to be accurate, precise, linear, specific, sensitive, rugged, robust, and useful for characterizing the stability of this chemical.

  18. Adsorption analysis equilibria and kinetics

    CERN Document Server

    Do, Duong D

    1998-01-01

    This book covers topics of equilibria and kinetics of adsorption in porous media. Fundamental equilibria and kinetics are dealt with for homogeneous as well as heterogeneous particles. Five chapters of the book deal with equilibria and eight chapters deal with kinetics. Single component as well as multicomponent systems are discussed. In kinetics analysis, we deal with the various mass transport processes and their interactions inside a porous particle. Conventional approaches as well as the new approach using Maxwell-Stefan equations are presented. Various methods to measure diffusivity, such

  19. A Simple HPLC-ELSD Method for Sugar Analysis in Goji Berry

    OpenAIRE

    D. Montesano; L. Cossignani; L. Giua; E. Urbani; M. S. Simonetti; F. Blasi

    2016-01-01

    Fructose, glucose, and sucrose were identified and quantified in commercial samples of Lycium barbarum L. fruits (goji berries) by high performance liquid chromatography-evaporative light scattering detector (HPLC-ELSD) method. This study described a rapid, simple, sensitive, selective, and reliable HPLC method suitable for the profiling of major sugars in berries, the evaluation of the nutritional/energetic properties, and assessment of the maturation stage. The proposed analytical method wa...

  20. Anti-acetylcholinesterase and antioxidant activities and HPLC-MS analysis of polyphenol from extracts of Nelsonia canescens (Lam. Spreng.

    Directory of Open Access Journals (Sweden)

    Nab èrè Ouattara

    2013-10-01

    Full Text Available Objective: To investigate the anti-acetylcholinesterase and antioxidant activities and to evaluate the major polyphenolic compounds of Nelsonia canescens extracts. Methods: The anti-acetylcholinesterase activity was assessed using a kinetic inhibition standard method. Two methods, ABTS and lipid peroxidation, were used to estimate the antioxidant capacity. Polyphenols profile of the plant extract has been determined with a HPLC-MS method. Results: The results showed that butanol extract exhibited the best anti-acetylcholinesterase activity with inhibition percentage of (55.62依1.49%. The best 3 ethylbenzothiazoline-6-sulphonate radical cation scavenging capacity was found for ethyl acetate extract with a value of (56.20 依0.77 mg equivalent trolox/g while the crude extract showed the highest inhibition of the rat liver lipid peroxidation (52.57依1.20%. Polyphenols profile revealed the presence of five phenol acids (p-coumaric acid, caffeic acid, chlorogenic acid, ferulic acid and gentisic acid and three flavonoids (apigenin, luteolin, quercetin. Conclusions: All the extracts of Nelsonia canescens exhibited antioxidant and AChE inhibition capacities. The active compounds identified and quantified in this species are mainly responsible for these in vitro biological activities and allow to justify its widely use in Burkina Faso traditional medicine.

  1. HPLC analysis of vitamin B6 in foods

    Directory of Open Access Journals (Sweden)

    V.-M. OLLILAINEN

    2008-12-01

    Full Text Available The objective of this work was to evaluate the methods for determination of vitamin B6 in foods. To achieve this, the literature review focused on sample treatment and liquid chromatographic analysis of vitamin B6 related compounds. In the experimental part, the chosen sample pretreatment and the high-performance liquid chromatographic (HPLC method were validated, and used to produce vitamin B6 data on various food items commonly consumed in Finland. The main emphasis of the sample treatment was on the extraction efficiency and the maintenance of the original concentration profile of the vitamers. Several acid extraction procedures were tested for this purpose. Perchloric acid was chosen as the extraction agent. Routine food analysis was then performed using dilute ice-cold perchloric acid extraction followed by an internally standardized ion-paired reversed-phase liquid chromatography. Food samples were hydrolyzed with takadiastase and alkaline phosphatase enzymes, phosphorylated and glycosylated vitamers were quantitated before and after the enzymatic digestion. This procedure enabled the extraction of vitamin B6 compounds in their intact forms, and the measurement of free, phosphorylated and glycosylated forms. The maintenance of the concentration profile of the vitamers was verified by using 14C -labeled pyridoxal 5'-phosphate in the examination of the extraction procedure. The extraction efficiency and laboratory performance were confirmed by interlaboratory studies. Up-to-date data on vitamin B6 content of about fifty common food items was produced. The data includes the results from meat and poultry, fish and fish product, dairy product, cereal and vegetable, and ready-to-eat food samples. Free and phosphorylated vitamin B6 compounds were measured in all food groups, and the glycosylated vitamer fraction was analyzed in all plant-derived foods. The results obtained in this work showed that vitamin B6 content of nearly all foods of plant

  2. Arsenic-containing fatty acids and hydrocarbons in marine oils - Determination using reversed-phase HPLC-ICP-MS and HPLC-qTOF-MS

    DEFF Research Database (Denmark)

    Sele, Veronika; Sloth, Jens Jørgen; Holmelid, Bjarte

    2014-01-01

    concentrations from 1.6 to 12.5 mg kg-1 oil, were analyzed for arsenolipids using reversed-phase high performance liquid chromatography coupled with inductively coupled plasma mass spectrometry (HPLC-ICP-MS). The arsenolipids were quantified using three different arsenic-containing calibration standards...

  3. Isolation and characterisation of selected germander diterpenoids from authenticated Teucrium chamaedrys and T. canadense by HPLC, HPLC-mS and NMR.

    Science.gov (United States)

    Sundaresan, P Ramnathan; Slavoff, Sarah A; Grundel, Erich; White, Kevin D; Mazzola, Eugene; Koblenz, Daniel; Rader, Jeanne I

    2006-01-01

    Teucrium species, such as germander, are rich in neo-clerodane diterpenoids and have been used in traditional folk medicine for their stimulant, diuretic, antipyretic and antiseptic properties. However, the furano neo-clerodane diterpenoids present in germander have been implicated in the in vivo hepatotoxicity of this botanical. In this study, authenticated germander (Teucrium chamaedrys L. and Teucrium canadense L.) was used as the source material. Methanol extracts of powdered plant mate rial were prepared and analysed by HPLC using Synergi Max-RP columns with monitoring at 220 nm. Limited amounts of teucrin A and other diterpenoid standards were analysed on a Synergi Max-RP column in order to determine their retention times and to generate calibration curves. The same standards were subjected to concurrent mass spectral analysis. Teucrin A and diterpenoids such as dihydroteugin, teuflin, teuflidin and teucvidin were tentatively identified in the plant extracts by HPLC-MS and 1H-NMR experiments. For the isolation of teucrium diterpenoids on a semipreparative scale, a solid-phase extraction method was developed for the first time using styrene divinylbenzene and strata-X sorbents for teucrin A and teuflin, respectively. Semi-preparative HPLC of the methanol extract of the powdered aerial parts of Teucrium plants was carried out on a semipreparative Synergi Max-RP column with photodiode array detection in order to confirm the identities of some diterpenoids by HPLC-MS and NMR.

  4. Kinetics of Social Contagion

    Science.gov (United States)

    Ruan, Zhongyuan; Iñiguez, Gerardo; Karsai, Márton; Kertész, János

    2015-11-01

    Diffusion of information, behavioral patterns or innovations follows diverse pathways depending on a number of conditions, including the structure of the underlying social network, the sensitivity to peer pressure and the influence of media. Here we study analytically and by simulations a general model that incorporates threshold mechanism capturing sensitivity to peer pressure, the effect of "immune" nodes who never adopt, and a perpetual flow of external information. While any constant, nonzero rate of dynamically introduced spontaneous adopters leads to global spreading, the kinetics by which the asymptotic state is approached shows rich behavior. In particular, we find that, as a function of the immune node density, there is a transition from fast to slow spreading governed by entirely different mechanisms. This transition happens below the percolation threshold of network fragmentation, and has its origin in the competition between cascading behavior induced by adopters and blocking due to immune nodes. This change is accompanied by a percolation transition of the induced clusters.

  5. The temperature hydration kinetics

    Directory of Open Access Journals (Sweden)

    Mircea Oroian

    2017-07-01

    Full Text Available The aim of this study is to evaluate the hydration kinetics of lentil seeds (Lens culinaris in water at different temperatures (25, 32.5, 40, 55, 70 and 80 °C for assessing the adequacy of models for describing the absorption phenomena during soaking. The diffusion coefficient values were calculated using Fick’s model for spherical and hemispherical geometries and the values were in the range of 10−6 m2/s. The experimental data were fitted to Peleg, Sigmoidal, Weibull and Exponential models. The models adequacy was determined using regression coefficients (R2, root mean square error (RMSE and reduced chi-square (χ2. The Peleg model is the suitable one for predicting the experimental data. Temperature had a positive and significant effect on the water absorption capacities and absorption was an endothermic process.

  6. Kinetics of Social Contagion

    CERN Document Server

    Ruan, Zhongyuan; Karsai, Marton; Kertesz, Janos

    2015-01-01

    Diffusion of information, behavioural patterns or innovations follows diverse pathways depending on a number of conditions, including the structure of the underlying social network, the sensitivity to peer pressure and the influence of media. Here we study analytically and by simulations a general model that incorporates threshold mechanism capturing sensitivity to peer pressure, the effect of `immune' nodes who never adopt, and a perpetual flow of external information. While any constant, non-zero rate of dynamically-introduced innovators leads to global spreading, the kinetics by which the asymptotic state is approached show rich behaviour. In particular we find that, as a function of the density of immune nodes, there is a transition from fast to slow spreading governed by entirely different mechanisms. This transition happens below the percolation threshold of fragmentation of the network, and has its origin in the competition between cascading behaviour induced by innovators and blocking of adoption due ...

  7. KINETIC SPECTROPHOTOMETRIC DETERMINATION OF SOME ...

    African Journals Online (AJOL)

    Preferred Customer

    ABSTRACT. A simple and sensitive kinetic spectrophotometric method was developed for the determination of some fluoroquinolonea antibiotics; gemifloxacin mesylate, moxifloxacin hydrochloride and gatifloxacin in bulk and in pharmaceutical preparations. The method is based upon a kinetic investigation of the oxidation ...

  8. Dimensional enhancement of kinetic energies

    DEFF Research Database (Denmark)

    Schleich, W.P.; Dahl, Jens Peder

    2002-01-01

    Simple thermodynamics considers kinetic energy to be an extensive variable which is proportional to the number N of particles. We present a quantum state of N noninteracting particles for which the kinetic energy increases quadratically with N. This enhancement effect is tied to the quantum centr...

  9. Cluster analysis of historical and modern hard red spring wheat cultivars based on parentage and HPLC analysis of gluten forming proteins

    Science.gov (United States)

    In this study, 30 hard red spring (HRS) wheat cultivars released between 1910 and 2013 were analyzed to determine how they cluster in terms of parentage and protein data, analyzed by reverse-phase HPLC (RP-HPLC) of gliadins, and size-exclusion HPLC (SE-HPLC) of unreduced proteins. Dwarfing genes in...

  10. Effect of analyte properties on the kinetic performance of liquid chromatographic separations.

    Science.gov (United States)

    de Villiers, André; Lynen, Frédéric; Sandra, Pat

    2009-04-17

    Advances in modern high-performance liquid chromatography (HPLC) have led to increased interest in the comparison of the ultimate performance limits of methodologies aimed at increasing the resolving power per unit time. Kinetic plot-based methods have proven invaluable in facilitating such evaluations. However, in bridging the gap between fundamental comparisons and the eventual practical applicability of kinetic performance data, the effect of analyte properties have thus far largely been neglected. Using pharmaceutical compounds as representative real-life analytes, it is demonstrated that noteworthy differences in the optimal kinetic performance of a chromatographic system are observed compared to data for common test compounds. For a given stationary phase particle size, higher optimal- and maximum plate numbers, corresponding to increased analysis times, are measured for pharmaceutical compounds. Moreover, it is found that the optimal particle size/maximum pressure combination depends on the analyte under investigation, with the beneficial range of efficiencies for small particles shifted towards higher plate numbers for drug molecules. It is further demonstrated that the pH of the mobile phase plays a crucial role in determining the kinetic performance of pharmaceutical compounds. These data clearly indicate that data for test compounds do not reflect the performance attainable for pharmaceutical compounds and highlights the importance of using real-life samples to perform kinetic evaluations.

  11. KINETICS OF THE ACETYLCHOLINESTERASE (AchE INHIBITION

    Directory of Open Access Journals (Sweden)

    Hendry Yanuar

    2010-06-01

    Full Text Available Acetylcholinesterase (AchE is an enzyme, which work on acetylcholine hydrolysis. Some insecticides can inhibit the activities of this enzyme. The purpose of this research was determined the kinetics of the AchE inhibition over the organophosphate and carbamat inhibitors with the methylindoxylacetate (MIA as a substrate. The AchE extract was obtained from the local honeybee head (100 heads on the 5 mL of phosphate buffer 0.05 M. Based on the preliminary analysis, the volume of the enzyme extract for the reaction rate was 100 mL on 1-5 mL of the substrate. Monocrothopos, Carbophenathion, Baycarb and MIPC were used as inhibitors which the concentration were 0.0018, 0.0030, and 0.0042 mg/mL respectively. The reaction rate were measured by Fluorescence HPLC Monitor (Shimadzu RF 535 at 540 nm, and some computational program were used on data analysis. The result of this research showed that the maximum rate of MIA hydrolysis by AchE  without the presence of inhibitor was 5.16 mL/s and the hydrolysis constant (Km was 3.49, and the inhibitors did not influence the maximum rate of substrate hydrolysis. It was finally concluded that the kinetics of AchE inhibition on MIA hydrolysis over the organophosphate and carbamat inhibitors was the competitive inhibition. Keyword: acetylcholinesterase, inhibition, organophosphate, carbamat

  12. Restructuration kinetics of amphiphilic intraocular lenses during aging.

    Science.gov (United States)

    Tortolano, Lionel; Saunier, Johanna; Hammami, Senda; Manerlax, Katia; Matmati, Houssem; Do, Bernard; Jubeli, Emile; Fattal, Elias; Yagoubi, Najet

    2018-01-01

    Photooxidation and hydrolysis are the two primary aging factors of intraocular lenses. Opacifications, dislocations, glistening and yellowing of the implanted acrylic lenses, which are due to chain scissions and depolymerization, are the consequences of aging from the clinical perspective. The purpose of this study was to examine the consequence of the aging of intraocular lenses on chemical and surface properties. Acrylic lenses made of poly acrylic-co-polystyrene polymer were artificially aged by photooxidation and hydrolysis from 2 to 20 years. Degradation products were observed by Reverse-phase High-Performance Liquid Chromatography RP-HPLC and thermogravimetric analysis (TGA). The surface, which was analyzed by atomic force microscopy (AFM) and fibronectin adhesion kinetics, was chosen as an indicator of intraocular biocompatibility. Low-molecular-weight degradation products (LMWP) result from chain scission under both hydrolysis and photooxidation. The osmotic effects of water enable degradation products to migrate through the polymer. A portion of the degradation products exudate in the surrounding center, whereas a portion link with lateral chains of the polymer. At the same time, the surface roughness evolves to externalize the most hydrophilic chains. As a result, the fibronectin adhesion level decrease with time, which indicates the existence of a biocompatible kinetic for implanted intraocular lenses. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Modeling the kinetics of vulcanization polydienes

    National Research Council Canada - National Science Library

    V. I. Molchanov; O. V. Karmanova; S. G. Tikhomirov

    2013-01-01

    A model of vulcanization kinetics, which allows describing the kinetic curves of any form and on the basis of economical laboratory experiment analytically evaluate the kinetics of isothermal curing was proposed...

  14. An Efficient Method for the Preparative Isolation and Purification of Flavonoid Glycosides and Caffeoylquinic Acid Derivatives from Leaves of Lonicera japonica Thunb. Using High Speed Counter-Current Chromatography (HSCCC) and Prep-HPLC Guided by DPPH-HPLC Experiments

    OpenAIRE

    Daijie Wang; Ning Du; Lei Wen; Heng Zhu; Feng Liu; Xiao Wang; Jinhua Du; Shengbo Li

    2017-01-01

    In this work, the n-butanol extract from leaves of Lonicera japonica Thunb. (L. japonica) was reacted with DPPH and subjected to a HPLC analysis for the guided screening antioxidants (DPPH-HPLC experiments). Then, nine antioxidants, including flavonoid glycosides and caffeoylquinic acid derivatives, were isolated and purified from leaves of L. japonica using high speed counter-current chromatography (HSCCC) and prep-HPLC. The n-butanol extract was firstly isolated by HSCCC using methyl tert...

  15. Simultaneous detection of water-soluble vitamins using the High Performance Liquid Chromatography (HPLC - a review

    Directory of Open Access Journals (Sweden)

    Rosemond Godbless Dadzie

    2014-01-01

    Full Text Available The water-soluble vitamins (WSV: ascorbic acid (vitamin C, thiamine (B1, riboflavin (B2, niacin (B3, panthothenic acid (B5, pyridoxine, and pyridoxal (B6, folic acid (B9, biotin(B8 , and B12 are very essential in the diet of humankind. As a result of ever increasing pressures from both consumers and legal enforcers, to specify accurately nutritive compositions of WSV that are present in food materials, many researchers have attempted to fill this niche through the provision of highly sensitive and rapid high performance liquid chromatography (HPLC procedures. In view of the health benefits of WSV, a replete of HPLC methods have been developed for simultaneous determination of their contents in nature and fortified food samples, nutritional supplements, as well as blood plasmas. The rate of losses of these vitamins during food processing and analysis, in addition to their transient dynamics, presents complexities in developing a highly sensitive HPLC procedure for their simultaneous separations and assays. This review critically assesses the different HPLC procedures developed by researchers and available in the open literature for simultaneous determination of water-soluble vitamins (WSV in dried tropical fruits materials. The study revealed that not a single chromatographic run developed by researchers can simultaneously elute all the WSV at a time. However, the HPLC procedures that are capable of determining all the WSV were coupled with electrospray ionization mass spectroscopy (ESI-MS, thus making the set-up expensive.

  16. Kinetics of Levoglucosenone Isomerization.

    Science.gov (United States)

    Krishna, Siddarth H; Walker, Theodore W; Dumesic, James A; Huber, George W

    2017-01-10

    We studied the acid-catalyzed isomerization of levoglucosenone (LGO) to 5-hydroxymethylfurfural (HMF) and developed a reaction kinetics model that describes the experimental data across a range of conditions (100-150 °C, 50-100 mm H2 SO4 , 50-150 mm LGO). LGO and its hydrated derivative exist in equilibrium under these reaction conditions. Thermal and catalytic degradation of HMF are the major sources of carbon loss. Within the range of conditions studied, higher temperatures and shorter reaction times favor the production of HMF. The yields of HMF and levulinic acid decrease monotonically as tetrahydrofuran is added to the aqueous solvent system, indicating that water plays a role in the LGO isomerization reaction. Initial-rate analyses show that HMF is produced solely from LGO rather than from the hydrated derivative of LGO. The results of this study are consistent with a mechanism for LGO isomerization that proceeds through hydration of the anhydro bridge, followed by ring rearrangement analogous to the isomerization of glucose to fructose. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Kinetic properties of cyanase.

    Science.gov (United States)

    Anderson, P M; Little, R M

    1986-04-08

    Cyanase is an inducible enzyme in Escherichia coli that catalyzes the hydrolysis of cyanate. Bicarbonate is required for activity, perhaps as a substrate, and the initial product of the reaction is carbamate, which spontaneously breaks down to ammonia and bicarbonate [Anderson, P. M. (1980) Biochemistry 19, 2882]. The purpose of this study was to characterize the kinetic properties of cyanase. Initial velocity studies showed that both cyanate and bicarbonate act as competitive substrate inhibitors. A number of monovalent anions act as inhibitors. Azide and acetate appear to act as competitive inhibitors with respect to cyanate and bicarbonate, respectively. Chloride, bromide, nitrate, nitrite, and formate also inhibit, apparently as the result of binding at either substrate site. Malonate and several other dicarboxylic dianions at very low concentrations display "slow-binding", reversible inhibition which can be prevented by saturating concentrations of either substrate. The results are consistent with a rapid equilibrium random mechanism in which bicarbonate acts as a substrate, bicarbonate and cyanate bind at adjacent anion-binding sites, and both substrates can bind at the other substrate anion binding site to give a dead-end complex.

  18. Analysis of flame retardant additives in polymer fractions of waste of electric and electronic equipment (WEEE) by means of HPLC-UV/MS and GPC-HPLC-UV.

    Science.gov (United States)

    Schlummer, Martin; Brandl, Fritz; Mäurer, Andreas; van Eldik, Rudi

    2005-01-28

    An HPLC-UV/MS method has been developed to identify and quantify flame retardants in post-consumer plastics from waste of electric and electronic equipment (WEEE). Atmospheric pressure chemical ionisation spectra of 15 brominated and phosphate-based flame retardants were recorded and interpreted. The method was applied to detect flame retardant additives in polymer extracts obtained from pressurised liquid extraction of solid polymers. In addition, a screening method was developed for soluble styrene polymers to isolate a flame retardant fraction through the application of gel permeation chromatography (GPC). This fraction was transferred to an online-coupled HPLC column and detected by UV spectroscopy, which allowed a reliable qualitative and quantitative analysis of brominated flame retardants in the polymer solutions.

  19. Separation and identification of the phthalic anhydride derivatives of Liqusticum Chuanxiong Hort by GC-MS, TLC, HPLC-DAD, and HPLC-MS.

    Science.gov (United States)

    Li, Hong-Xia; Ding, Ming-Yu; Yu, Jian-Yuan

    2002-03-01

    A simple, sensitive, and rapid method using gas chromatography (GC)-mass spectrometry (MS) is developed for the simultaneous separation and identification of the active ingredients of Liqusticum Chuanxiong Hort (Chuanxiong). Ten phthalic anhydride derivatives (PADs) are identified in Chuanxiong as 3-butylphthalide, 3-butylidenephthalide, 3-butylidene-4-hydroxyphthalide, senkyunolide A, neocnidilide, Z-ligustilide, E-ligustilide, senkyunolide F, senkyunolide-H, and senkyunolide-I. The existence of ferulic acid and vanillin in Chuanxiong extract is also demonstrated. Further identification of these compounds is performed by thin-layer chromatography, high-performance liquid chromatography (HPLC), and HPLC-MS analysis. This is the first report of the separation and determination of the PADs in Chuanxiong by GC-MS.

  20. Nonanthocyanin secondary metabolites of black raspberry (Rubus occidentalis L.) fruits: identification by HPLC-DAD, NMR, HPLC-ESI-MS, and ESI-MS/MS analyses.

    Science.gov (United States)

    Paudel, Liladhar; Wyzgoski, Faith J; Scheerens, Joseph C; Chanon, Ann M; Reese, R Neil; Smiljanic, Danijela; Wesdemiotis, Chrys; Blakeslee, Joshua J; Riedl, Kenneth M; Rinaldi, Peter L

    2013-12-11

    Nonanthocyanin secondary metabolites potentially contributing to the antiproliferative bioactivity of black raspberry ( Rubus occidentalis L.) fruits were extracted in ethyl acetate and isolated by semipreparative and analytical HPLC and analyzed by NMR, HPLC-ESI-MS, and ESI-MS/MS techniques. Here we present complete and partial structures of a variety of the chemical entities such as quercetin 3-glucoside, quercetin 3-rutinoside, myricetin glucoside, dihydrokaempferol glucoside, benzoic acid β-d-glucopyranosyl ester, 3,4-dihydroxybenzoic acid, epicatechin, caffeic acid, p-coumaric acid, p-coumaryl glucoside, p-coumaryl sugar ester, ellagic acid, methyl ellagic acid acetylpentose, methyl ellagic acid valerylpentose, trans-piceid, phloretin glucoside (phloridzin), dihydrosinapic acid, salicylic acid β-d-glucopyranosyl ester, a salicylic acid derivative without attached sugar, p-alkylphenyl glucoside, and a citric acid derivative. To our knowledge, 15 of these compounds were not previously reported in black raspberry fruits.

  1. ANALISIS RESIDU KLORPIRIFOS DALAM SAYUR-SAYURAN DENGAN TEKNIK HIGH PERFORMANCE LIQUID CHROMATOGRAPHY (HPLC

    Directory of Open Access Journals (Sweden)

    Aman Sentosa Panggabean

    2016-06-01

    Full Text Available The research about analysis of chlorpyrifos residue in vegetables by using High Performance Liquid Chromatography (HPLC technique has been done. To obtain the optimal measurement results, the measurement performed several important parameters in the chromatographic system was composition of mobile phase, volume injection sample, flow rate and pH eluent. Optimum measurement conditions obtained was mobile phase composition (water : methanol with 70 : 30, volume injection sample are 5 mL, flow rate are 0.5mL/menit and pH eluent are 7. The analytical performance that obtained is good showed with the reproducibility value as percentage coefficient variance (% CV was 0.0664%, limit of detection (LOD was 0.44 ppm, with a recovery percentage of > 95%. The results obtained showed the HPLC technique can be used for the routine analysis in the determination of chlorpyrifos for the vegetable samples. Keywords: Chlorpyrifos, Vegetables, HPLC.

  2. Monitoring of monosaccharides, oligosaccharides, ethanol and glycerol during wort fermentation by biosensors, HPLC and spectrophotometry.

    Science.gov (United States)

    Monošík, Rastislav; Magdolen, Peter; Stredanský, Miroslav; Šturdík, Ernest

    2013-05-01

    The aim of the present study was to analyze sugar levels (namely maltose, maltotriose, glucose and fructose) and alcohols (ethanol and glycerol) during the fermentation process in wort samples by amperometric enzymatic biosensors developed by our research group for industrial application, HPLC and spectrophotometry, and to compare the suitability of the presented methods for determination of individual analytes. We can conclude that for the specific monitoring of maltose or maltotriose only the HPLC method was suitable. On the other hand, biosensors and spectrophotometry reflected a decrease in total sugar concentration better and were able to detect both glucose and fructose in the later stages of fermentation, while HPLC was not. This can be attributed to the low detection limits and good sensitivity of the proposed methods. For the ethanol and glycerol analysis all methods proved to be suitable. However, concerning the cost expenses and time analysis, biosensors represented the best option. Copyright © 2012 Elsevier Ltd. All rights reserved.

  3. Brief on -Hyphenated Methods of HPLC for Determining the Presence of Solutes.

    Directory of Open Access Journals (Sweden)

    Mohamad Taleuzzaman

    2017-02-01

    Full Text Available HPLC is the tool in liquid chromatography is unique because of particle size, smaller particle in the stationary phase, increase efficiency of a separation. However, if the particles are made smaller, capillary action increases and it becomes more difficult to drain the column under gravity. For quantitative analysis different types of detector is used in conjunction with HPLC which give precise and accurate result and it is apply according to the nature of the substance. Various types of detectors used in HPLC are mass spectrometry, infrared spectroscopy, visible spectroscopy, ultraviolet spectroscopy, fluorescence spectroscopy, nuclear magnetic resonance, conductivity measurement, and refractive index measurement. Each detector has its assets, limitations and sample types for which it is most effective. The recent development of the so-called hyphenated techniques has improved the ability to separate and identify multiple entities within a mixture.

  4. PREPARATIVE ISOLATION AND PURIFICATION OF CHEMICAL CONSTITUENTS OF BELAMCANDA BY MPLC, HSCCC AND PREP-HPLC

    Science.gov (United States)

    Wang, Xiaohong; Liang, Yong; Peng, Cuilin; Xie, Huichun; Pan, Man; Zhang, Tianyou; Ito, Yoichiro

    2010-01-01

    Combined with medium-pressure liquid chromatography (MPLC) and preparative high-pressure liquid chromatography (Prep-HPLC), high-speed countercurrent chromatography (HSCCC) was successfully applied for separation and purification of isoflavonoids from the extract of belamcanda. HSCCC separation was performed on a two-phase solvent system composed of methyl tert-butyl ether -ethyl acetate - n-butyl alcohol – acetonitrile −0.1% aqueous trifluoroacetic acid at a volume radio of 1:2:1:1:5. Semi-purified peak fractions from HSCCC separation were further purified by Prep-HPLC. Nine well-separated fractions were analyzed by HPLC-UV absorption spectrometry to determine their purities and characterized with ESI-MSn. Except for peaksland VII (unknown) seven compounds were identified as apocynin (peak II), mangiferin (peak III), 7-O-methylmangiferin (peak IV), hispidulin (peak V), 3′-hydroxyltectoridin (peak VI), iristectorin B (peak VII), isoiridin (peak IX). PMID:21552369

  5. [Separation and preparation of indole alkaloids in Lycorma delicatula White. by HPLC].

    Science.gov (United States)

    Xue, G; Yuan, S

    1996-09-01

    A HPLC method for separating and preparing indole alkaloids is described. HPLC conditions for analysis: BIO-RAD series 700 HPLC, model 700 data station, UV: model 1749 UV-VIS monitor, column: BIO-RAD Hi-pore RP318, 250 mm x 10 mm, mobile phase: 80% methanol-H2O(gradient), flow rate: 1.5 ml/min, detection wavelength: 254 nm. On the basis of spectral (1HNMR, 13CNMR, H-H COSY, MS, DEPT) and chemical evidence, the structures of two compounds were elucidated as beta-yohimbine (yohimban-16-carboxylic acid-17-hydroxy methylester (3 alpha, 16 alpha, 17 beta)) and ajmalicine (oxayohimban-16-carboxylic acid-16,17-didehydro-19-ethyl methyl ester (19 alpha)).

  6. Validated Reverse Phase HPLC Method for the Determination of Impurities in Etoricoxib

    Directory of Open Access Journals (Sweden)

    S. Venugopal

    2011-01-01

    Full Text Available This paper describes the development of reverse phase HPLC method for etoricoxib in the presence of impurities and degradation products generated from the forced degradation studies. The drug substance was subjected to stress conditions of hydrolysis, oxidation, photolysis and thermal degradation. The degradation of etoricoxib was observed under base and oxidation environment. The drug was found stable in other stress conditions studied. Successful separation of the drug from the process related impurities and degradation products were achieved on zorbax SB CN (250 x 4.6 mm 5 μm particle size column using reverse phase HPLC method. The isocratic method employed with a mixture of buffer and acetonitrile in a ratio of 60:40 respectively. Disodium hydrogen orthophosphate (0.02 M is used as buffer and pH adjusted to 7.20 with 1 N sodium hydroxide solution. The HPLC method was developed and validated with respect to linearity, accuracy, precision, specificity and ruggedness.

  7. The validation of plasma darunavir concentrations determined by the HPLC method for protease inhibitors.

    Science.gov (United States)

    Takahashi, Masaaki; Kudaka, Yuichi; Okumura, Naoya; Hirano, Atsushi; Banno, Kazuhide; Kaneda, Tsuguhiro

    2007-10-01

    Darunavir (DRV) is a new protease inhibitor used to treat human immunodeficiency virus (HIV) type-1. The aim of this study was to validate the determination of plasma DRV concentrations using the HPLC method, a simple procedure for simultaneous determination of seven HIV protease inhibitors and efavirenz. The calibration curve was linear (range of 0.13 to 10.36 microg/ml). The average accuracy ranged from 100.7 to 105.6%. Both the interday and intraday coefficients of variation were less than 6.7%, which was similar to or much lower than previously reported values by the LC/MS/MS method. It is concluded that HPLC can be used to determine plasma DRV concentrations and routinely in the clinical setting; thus, this HPLC method enables further study of DRV pharmacokinetics in conventional hospital laboratories.

  8. Improved method for HPLC analysis of polyamines, agmatine and aromatic monoamines in plant tissue

    Science.gov (United States)

    Slocum, R. D.; Flores, H. E.; Galston, A. W.; Weinstein, L. H.

    1989-01-01

    The high performance liquid chromatographic (HPLC) method of Flores and Galston (1982 Plant Physiol 69: 701) for the separation and quantitation of benzoylated polyamines in plant tissues has been widely adopted by other workers. However, due to previously unrecognized problems associated with the derivatization of agmatine, this important intermediate in plant polyamine metabolism cannot be quantitated using this method. Also, two polyamines, putrescine and diaminopropane, also are not well resolved using this method. A simple modification of the original HPLC procedure greatly improves the separation and quantitation of these amines, and further allows the simulation analysis of phenethylamine and tyramine, which are major monoamine constituents of tobacco and other plant tissues. We have used this modified HPLC method to characterize amine titers in suspension cultured carrot (Daucas carota L.) cells and tobacco (Nicotiana tabacum L.) leaf tissues.

  9. Determination of free salicylic acid in chewing aspirin tablets by HPLC.

    Science.gov (United States)

    Tian, Jun; Chen, Xin-shan; Wang, Rui-dong

    2003-07-01

    To establish a HPLC method for determining the content of free salicylic acid in chewing aspirin tablets. The determination was conducted on a HPLC column (C(18), 150 mm x 4.6 mm x 5 microm) with methanol-water-glacial acetic acid (8.0 5.5 1.0) as the mobile phase and the detection wavelength of 302 nm. The calibration curve was linear within the concentration range of 2.65 to 31.77 microg/ml (r=0.999 97) of salicylic acid. The average recovery rate was 100.21% with relative standard deviation of 0.53% (n=6). HPLC is quick and accurate of determining the content of free salicylic acid for chewing aspirin tablets.

  10. HPLC Fingerprint Analysis Combined with Chemometrics for Authentication of Kaempferia galanga from Related Species

    Directory of Open Access Journals (Sweden)

    Cahya Septyanti

    2016-12-01

    Full Text Available Fingerprint analysis using high performance liquid chromatography (HPLC has been developed for authentication of Kaempferia galanga from related species, such as Kaempferia pandurata and K. rotunda. By comparing the fingerprint chromatograms of K. galanga, K. pandurata and K. rotunda, we could identify K. galanga samples and detect adulteration of K. galanga from K. pandurata and K. rotunda by using their marker peaks. We also combined HPLC fingerprint with chemometrics for discrimination the three species and also for authentication of K. galanga. All the three species and K. galanga adulterated with K. pandurata and K. rotunda were discriminated successfully by using principal component analysis (PCA and discriminant analysis (DA. This result indicates that HPLC fingerprint analysis in combination with PCA (PC1 = 30.06% and PC2 = 34.74% and DA (DF1 = 94.59% and DF2 = 3.32% could be used for authentication of K. galanga samples from the related species.

  11. Analysis of the extracts of Isatis tinctoria by new analytical approaches of HPLC, MS and NMR.

    Science.gov (United States)

    Zhou, Jue; Qu, Fan

    2011-01-01

    The methods of extraction, separation and analysis of alkaloids and indole glucosinolates (GLs) ofIsatis tinctoria were reviewed. Different analytical approaches such as High-pressure Liquid Chromatography (HPLC), Liquid Chromatography with Electrospray Ionization Mass Spectrometry (LC/ESI/MS), Electrospray Ionization Time-Of-Flight Mass Spectrometry (ESI-TOF-MS), and Nuclear Magnetic Resonance (NMR) were used to validate and identity of these constituents. These methods provide rapid separation, identification and quantitative measurements of alkaloids and GLs of Isatis tinctoria. By connection with different detectors to HPLC such as PDA, ELSD, ESI- and APCI-MS in positive and negative ion modes, complicated compounds could be detected with at least two independent detection modes. The molecular formula can be derived in a second step of ESI-TOF-MS data. But for some constituents, UV and MS cannot provide sufficient structure identification. After peak purification, NMR by semi-preparative HPLC can be used as a complementary method.

  12. [Comparative study on HPLC fingerprint of ordinary powder and ultrafine powder for Gardenia jasminoides f. longicarpa].

    Science.gov (United States)

    Ju, Ai-Hua; Zhou, Kai; Zhang, Jing; Cai, Li-Juan; Song, Ping-Ping

    2013-07-01

    To establish an HPLC fingerprint of Gardenia jasminoides f. longicarpa and compare the differences between its ordinary powder and ultrafine powder. The analysis was carried out on a Kromasil C18 (250 mm x 4.6 mm, 5 microm) column with gradient elution of acetonitrile-0.4% phosphoric acid at the flow rate of 1.0 ml/min. The wavelength was 240 nm during 0 - 40 min and 440 nm during 40 - 80 min. HPLC fingerprint of Gardenia jasminoides f. longicarpa was established, 23 common peaks were identified,and the similarity of 10 samples was greater than 0.9. Ultrafine grinding did not change the types and number of chemical compositions, but it obviously increased the content of main chemical compositions. The HPLC fingerprint is accurate, reliable and repeatable, which can be used for quality control of Gardenia jasminoides f. longicarpa. Ultrafine grinding can stimulate the release of chemical components of Gardenia jasminoides f. longicarpa.

  13. Kinetic ELISA in microfluidic channels

    National Research Council Canada - National Science Library

    Yanagisawa, Naoki; Dutta, Debashis

    2011-01-01

    In this article, we describe the kinetic ELISA of Blue Tongue and Epizootic Hemorrhagic Disease viral antibodies in microfluidic channels by monitoring the rate of generation of the enzyme reaction...

  14. Development and application of HPLC-RI and HPLC-MS/MS based methods for quantification of residual deoxycholate levels in pneumococcal polysaccharides.

    Science.gov (United States)

    Gairola, Sunil; Gautam, Manish; Patil, Dada; Manoj Kumar, Krishna; Shinde, Pravin; Jana, S K; Dhere, Rajeev; Jadhav, Suresh

    2016-11-01

    The analysis of residual sodium deoxycholate (DOC); a detergent of biological origin used in manufacturing of polysaccharide vaccines is challenging due to complex sample matrices and the lack of suitable methods. Here we report, rapid and sensitive high-performance liquid chromatography-refractive index (HPLC-RI) and tandem mass spectrometry (HPLC-MS/MS) methods for estimation of residual DOC in pneumococcal polysaccharides. For HPLC-RI method, separation was achieved using Luna C18 column and mobile phase compositions of acetonitrile: methanol: 20 mM sodium acetate (60:05:35% v/v). For HPLC-MS/MS method, separation was achieved using a Hypersil BDS C18 column with gradient elution of methanol and water (0.1% formic acid). MS/MS method showed linearity (r(2) = 0.997) over the range of 10-320 ng/mL with limits of detection (LOD) and lower limit of quantitation (LOQ) of 3 and 10 ng/mL respectively. Precision (% RSD) and accuracy (% recovery) for both methods were in the range of 0.74-8.29% and 82.33-117.86% respectively. Sample matrices interferences were addressed following novel sample clean-up method based on liquid-liquid extraction. Both methods enabled traceable quantitation of DOC in intermediate and purified pneumococcal polysaccharides of serotypes: 1, 5, 6A, 6B, 7F, 9V, 14, 19A, 19F and 23F. Copyright © 2016 International Alliance for Biological Standardization. Published by Elsevier Ltd. All rights reserved.

  15. Modelling Heart Rate Kinetics

    Science.gov (United States)

    Zakynthinaki, Maria S.

    2015-01-01

    The objective of the present study was to formulate a simple and at the same time effective mathematical model of heart rate kinetics in response to movement (exercise). Based on an existing model, a system of two coupled differential equations which give the rate of change of heart rate and the rate of change of exercise intensity is used. The modifications introduced to the existing model are justified and discussed in detail, while models of blood lactate accumulation in respect to time and exercise intensity are also presented. The main modification is that the proposed model has now only one parameter which reflects the overall cardiovascular condition of the individual. The time elapsed after the beginning of the exercise, the intensity of the exercise, as well as blood lactate are also taken into account. Application of the model provides information regarding the individual’s cardiovascular condition and is able to detect possible changes in it, across the data recording periods. To demonstrate examples of successful numerical fit of the model, constant intensity experimental heart rate data sets of two individuals have been selected and numerical optimization was implemented. In addition, numerical simulations provided predictions for various exercise intensities and various cardiovascular condition levels. The proposed model can serve as a powerful tool for a complete means of heart rate analysis, not only in exercise physiology (for efficiently designing training sessions for healthy subjects) but also in the areas of cardiovascular health and rehabilitation (including application in population groups for which direct heart rate recordings at intense exercises are not possible or not allowed, such as elderly or pregnant women). PMID:25876164

  16. Residue behaviors and dietary risk assessment of dinotefuran and its metabolites in Oryza sativa by a new HPLC-MS/MS method.

    Science.gov (United States)

    Li, Ruijuan; Liu, Tongjin; Cui, Shuhua; Zhang, Sicong; Yu, Jianlei; Song, Guochun

    2017-11-15

    In this study, we developed a new method to detect dinotefuran and its metabolites (UF and DN) in Oryza sativa (Rice) by HPLC-MS/MS in multiple reaction monitoring (MRM) modes. The recovery rates for dinotefuran, UF and DN were 82.3-85.8%, 83.7-89.0%, and 81.6-90.2%, respectively. The dissipation kinetics of dinotefuran in rice followed a combined first+first kinetic model, where the half-lives of dinotefuran and its metabolites were determined to be between 0.5 and 2.3days. The dinotefuran residue in brown rice sampled at day 7, 14, and 21 after the last application was 0.4131mg/kg with a very low risk quotient (RQ) value. We recommend that the safety interval of application for rice is 7days. The method developed in this study is simple and rapid, with high accuracy and precision which meet the requirements for quantitative analysis of dinotefuran in rice. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Identification and quantification of free, conjugate and total phenolic compounds in leaves of 20 sweetpotato cultivars by HPLC-DAD and HPLC-ESI-MS/MS.

    Science.gov (United States)

    Luo, Chunying; Wang, Xixi; Gao, Ge; Wang, Lian; Li, Yongxin; Sun, Chengjun

    2013-12-01

    The study systematically investigated free, conjugate and total phenolics (phenolic acids and flavonoids) in leaves of 19 Chinese and one American sweetpotato cultivars grown in China. Three extraction/hydrolytic methods (direct extraction and acidic and basic hydrolysis) for sample preparation were employed to obtain different forms of phenolics. Twenty-nine phenolics were separated and identified using HPLC-DAD and HPLC-ESI-MS/MS. Three quercetin glycosides were characterised for the first time from this plant. Contents of the principal phenolics identified were determined by the HPLC-DAD procedure, which was validated in terms of linearity, precision, accuracy and limit of detection and quantification. Moreover, to the best of our knowledge, it is the first to reveal and demonstrate artifacts of esterification during acidic methanolic and ethanolic hydrolysis, and chromatographic behaviours, UV spectra and MS data of 20 hydroxycinnamic acid methyl and ethyl esters were obtained using acidic methanolic and ethanolic hydrolysis. Copyright © 2013 Elsevier Ltd. All rights reserved.

  18. Screening and Analysis of the Potential Bioactive Components of Poria cocos (Schw. Wolf by HPLC and HPLC-MSn with the Aid of Chemometrics

    Directory of Open Access Journals (Sweden)

    Ling-Fang Wu

    2016-02-01

    Full Text Available The aim of the present study was to establish a new method based on Similarity Analysis (SA, Cluster Analysis (CA and Principal Component Analysis (PCA to determine the quality of different samples of Poria cocos (Schw. Wolf obtained from Yunnan, Hubei, Guizhou, Fujian, Henan, Guangxi, Anhui and Sichuan in China. For this purpose 15 samples from the different habitats were analyzed by HPLC-PAD and HPLC-MSn. Twenty-three compounds were detected by HPLC-MSn, of which twenty compounds were tentatively identified by comparing their retention times and mass spectrometry data with that of reference compounds and reviewing the literature. The characteristic fragmentations were summarized. 3-epi-Dehydrotumulosic acid (F13, 3-oxo-16α,25-dihydroxylanosta-7,9(11,24(31-trien-21-oic acid (F4, 3-oxo-6,16α-dihydroxylanosta-7,9(11,24(31-trien-21-oic acid (F7 and dehydropachymic acid (F15 were deemed to be suitable marker compounds to distinguish between samples of different quality according to CA and PCA. This study provides helpful chemical information for further anti-tumor activity and active mechanism research on P. cocos. The results proved that fingerprint combined with a chemometric approach is a simple, rapid and effective method for the quality discrimination of P. cocos.

  19. Screening and Analysis of the Marker Components in Ganoderma lucidum by HPLC and HPLC-MS(n) with the Aid of Chemometrics.

    Science.gov (United States)

    Wu, Lingfang; Liang, Wenyi; Chen, Wenjing; Li, Shi; Cui, Yaping; Qi, Qi; Zhang, Lanzhen

    2017-04-06

    Ganoderma triterpenes (GTs) are the major secondary metabolites of Ganoderma lucidum, which is a popularly used traditional Chinese medicine for complementary cancer therapy. The present study was to establish a fingerprint evaluation system based on Similarity Analysis (SA), Cluster Analysis (CA) and Principal Component Analysis (PCA) for the identification and quality control of G. lucidum. Fifteen samples from the Chinese provinces of Hainan, Neimeng, Shangdong, Jilin, Anhui, Henan, Yunnan, Guangxi and Fujian were analyzed by HPLC-PAD and HPLC-MS(n). Forty-seven compounds were detected by HPLC, of which forty-two compounds were tentatively identified by comparing their retention times and mass spectrometry data with that of reference compounds and reviewing the literature. Ganoderic acid B, 3,7,15-trihydroxy-11,23-dioxolanost-8,16-dien-26-oic acid, lucidenic acid A, ganoderic acid G, and 3,7-oxo-12-acetylganoderic acid DM were deemed to be the marker compounds to distinguish the samples with different quality according to both CA and PCA. This study provides helpful chemical information for further research on the anti-tumor activity and mechanism of action of G. lucidum. The results proved that fingerprints combined with chemometrics are a simple, rapid and effective method for the quality control of G. lucidum.

  20. Pharmacokinetic study of arctigenin in rat plasma and organ tissue by RP-HPLC method.

    Science.gov (United States)

    He, Fan; Dou, De-Qiang; Hou, Qiang; Sun, Yu; Kang, Ting-Guo

    2013-01-01

    A high-performance liquid chromatography (HPLC) technique was developed for the determination of arctigenin in plasma and various organs of rats after the oral administration of 30, 50 and 70 mgkg(-1) of arctigenin to the Sprague-Dawley rats. Results showed that the validated HPLC method was simple, fast, reproducible and suitable to the determination of arctigenin in rat plasma and organ tissue and one-compartmental model with zero-order absorption process can well describe the changes of arctigenin concentration in the plasma. The concentration of compound was highest in the spleen, less in the liver and the least in the lung.

  1. [Simultaneous analysis and detection of pesticides in fresh fruits and vegetables by HPLC and GC].

    Science.gov (United States)

    Tsuchiya, T; Maeda, K; Sekiguchi, Y; Hirahara, Y; Watanabe, Y; Tonogai, Y

    1998-01-01

    A method was established for simultaneous determination of pesticide residue in fresh fruits and vegetables by HPLC and GC. CH3CN extraction/NaCl partiton method was used in order to recover hydrophilic pesticide such as acephate, methamidophos. Dimethoate and methamidophos from okra and DDVP from strawberry were detected by GC. On the other hand confirmation method by GC and GC/MS was studied for peaks detected by HPLC with UV and/or FL detector. OPP, TBZ, imazalil chlorpyrifos etc. in citrus fruits were detected by the proposed method.

  2. SPE-HPLC purification of endocrine disrupting compounds from human serum for assessment of xenoestrogenic activity

    DEFF Research Database (Denmark)

    Hjelmborg, P.S.; Ghisari, Mandana; Bonefeld-Jørgensen, Eva

    2006-01-01

    Assessment of xenoestrogenic activity in human serum samples requires the removal of endogenous sex hormones to assure that the activity measured originates from xenobiotic compounds only. Serum samples representing high, medium and lower accumulation of persistent organic pollutants (POPs) were...... response curve. 17β-Estradiol titrations showed that the xenoestrogenic effects were mediated via ER. Moreover, our SPE-HPLC-ERE-CALUX assay was demonstrated to elicit high interlaboratory correlation. In the present study the combination of SPE-HPLC purification and the ex vivo estrogenic responses...

  3. Analysis of neutral lipids from microalgae by HPLC-ELSD and APCI-MS/MS.

    Science.gov (United States)

    Donot, F; Cazals, G; Gunata, Z; Egron, D; Malinge, J; Strub, C; Fontana, A; Schorr-Galindo, S

    2013-12-30

    A method was developed to analyze neutral lipids through the use of three triglycerides, four free fatty acids, six di- and four mono-glycerides standards by high performance liquid chromatography (HPLC) normal phase coupled with either with evaporative light scattering detector (ELSD) or with mass spectrometry (MS) operating in atmospheric pressure chemical ionization (APCI) mode. The method was applied to the determination of the neutral lipid fraction from a Botryococcus braunii race A (B. braunii) culture. This method led us to identify neutral lipids synthesized by B. braunii in a single analysis within 45min through HPLC-APCI-MS/MS technique. Copyright © 2013 Elsevier B.V. All rights reserved.

  4. A thin film degradation study of a fluorinated polyether liquid lubricant using an HPLC method

    Science.gov (United States)

    Morales, W.

    1986-01-01

    A High Pressure Liquid Chromatography (HPLC) separation method was developed to study and analyze a fluorinated polyether fluid which is promising liquid lubricant for future applications. This HPLC separation method was used in a preliminary study investigating the catalytic effect of various metal, metal alloy, and ceramic engineering materials on the degradation of this fluid in a dry air atmosphere at 345 C. Using a 440 C stainless steel as a reference catalytic material it was found that a titanium alloy and a chromium plated material degraded the fluorinated polyether fluid substantially more than the reference material.

  5. Crystallization Kinetics within a Generic Modelling Framework

    DEFF Research Database (Denmark)

    Meisler, Kresten Troelstrup; von Solms, Nicolas; Gernaey, Krist

    2013-01-01

    An existing generic modelling framework has been expanded with tools for kinetic model analysis. The analysis of kinetics is carried out within the framework where kinetic constitutive models are collected, analysed and utilized for the simulation of crystallization operations. A modelling...... procedure is proposed to gain the information of crystallization operation kinetic model analysis and utilize this for faster evaluation of crystallization operations....

  6. Identification of Radiodegradation Products of Acebutolol and Alprenolol by HPLC/MS/MS.

    Science.gov (United States)

    Ogrodowczyk, Magdalena; Dettlaff, Katarzyna; Kachlicki, Piotr; Marciniec, Barbara

    2015-01-01

    Two therapeutically active compounds from the group of β-blockers, acebutolol (AC) and alprenolol (AL), in solid form were subjected to ionizing radiation emitted by a beam of high energy electrons from an accelerator with a standard sterilization dose of 25 kGy and in higher doses of 50-400 kGy. The effects of irradiation were detected by chromatographic methods (TLC, HPLC) and a hyphenated method (HPLC/MS/MS). No significant changes in the physicochemical properties of both compounds studied irradiated with 25 kGy were noted, but upon irradiation with the highest dose (400 kGy) the loss of AC and AL content determined by HPLC was 2.79 and 9.12%, respectively. The product of AC decomposition and the two products of AL decomposition were separated and identified by HPLC/MS/MS. It has been established that radiodegradation of AC and AL takes place by oxidation, leading to formation of the products of radiolysis, most probably alcohol derivatives of the β-blockers studied. The additional product that appears on radiodegradation of AL is probably formed as a result of two simultaneous reactions: oxidation and CH2 group elimination.

  7. A RP-HPLC method for the determination of tea catechins

    NARCIS (Netherlands)

    Khokhar, S.; Venema, D.; Hollman, P.C.H.; Dekker, M.; Jongen, W.M.F.

    1997-01-01

    An HPLC method with gradient elution for the quantification of catechins ((−)-epigallocatechin (EGC), ( )-catechin (C), (−)-epicatechin (EC), (−)-epigallocatechingallate (EGCg) and (−)-epicatechingallate (ECg)) in tea was developed. The method was used to determine catechins in black tea, green tea

  8. Multielemental speciation analysis by advanced hyphenated technique - HPLC/ICP-MS: A review.

    Science.gov (United States)

    Marcinkowska, Monika; Barałkiewicz, Danuta

    2016-12-01

    Speciation analysis has become an invaluable tool in human health risk assessment, environmental monitoring or food quality control. Another step is to develop reliable multielemental speciation methodologies, to reduce costs, waste and time needed for the analysis. Separation and detection of species of several elements in a single analytical run can be accomplished by high performance liquid chromatography hyphenated to inductively coupled plasma mass spectrometry (HPLC/ICP-MS). Our review assembles articles concerning multielemental speciation determination of: As, Se, Cr, Sb, I, Br, Pb, Hg, V, Mo, Te, Tl, Cd and W in environmental, biological, food and clinical samples analyzed with HPLC/ICP-MS. It addresses the procedures in terms of following issues: sample collection and pretreatment, selection of optimal conditions for elements species separation by HPLC and determination using ICP-MS as well as metrological approach. The presented work is the first review article concerning multielemental speciation analysis by advanced hyphenated technique HPLC/ICP-MS. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. Determination of Trace Level Triclosan in Water by Online Preconcentration and HPLC-UV Diode Array

    Science.gov (United States)

    An online high performance liquid chromatography (HPLC) method for the detection and quantification of trace levels of triclosan in water is discussed. Triclosan, an anti-bacterial agent, and related compounds have been shown to reach municipal waste waters through the disposal ...

  10. [Comparative study of HPLC fingerprint between Zanthoxylum bungeanum and Zanthoxylum schinifolium].

    Science.gov (United States)

    Song, Li; Liu, You-Ping

    2012-01-01

    To establish the HPLC fingerprint of Zanthoxylum bungeanum and Zanthoxylum schinifolium for finding the difference. Samples were extracted with 50% methanol 25 mL by ultrasonic wave and then separated on Hypersil BDS C18 (250 mm x 4.6 mm, 5 microm) column. Gradient elution was carried out with a mobile phase of methanol-water. The detection wavelength was 268 nm, the column temperature was set at 35 degrees C, the flow rate was 1.0 mL/min and the analytic time was 130 min. The software "Similarity Evaluation System for Chromatographic Fingerprint of TCMs" (Version 2004A) was employed to generate the mean chromatogram and carry out the similarity analysis of the samples. SPSS 17.0 was employed to carry out the cluster analysis. Similarity of Z. bungeanum was 0.909 - 0.992 and that of Z. schinifolium was 0.930 - 0.999. There were 27 common peaks in HPLC Fingerprints of Z. bungeanum and 24 in that of Z. schinifolium. Their HPLC standard fingerprints were obvious difference. They belonged to different categories in cluster analysis. The method is simple, accurate and rapid. It could obviously distinguish Z. bungeanum from Z. schinifolium. So it suggests that HPLC fingerprints should be one of the quality control indexes of Zanthoxyli Pericarpium.

  11. Determination of acetylsalicylic acid and salicylic acid in foods, using HPLC with fluorescence detection.

    NARCIS (Netherlands)

    Venema, D.P.; Hollman, P.C.H.; Janssen, P.L.T.M.K.; Katan, M.B.

    1996-01-01

    We developed a specific and sensitive HPLC method with fluorescence detection for the determination of free acetylsalicylic acid, free salicylic acid, and free salicylic acid plus salicylic acid after alkaline hydrolysis (free-plus-bound) in foods. Acetylsalicylic acid was detected after postcolumn

  12. Simultaneous HPLC quantitative analysis of active compounds in leaves of Moringa oleifera Lam.

    Science.gov (United States)

    Vongsak, Boonyadist; Sithisarn, Pongtip; Gritsanapan, Wandee

    2014-08-01

    Moringa oleifera Lam. has been used as a traditional medicine for the treatment of numerous diseases. A simultaneous high-performance liquid chromatography (HPLC) analysis was developed and validated for the determination of the contents of crypto-chlorogenic acid, isoquercetin and astragalin, the primary antioxidative compounds, in M. oleifera leaves. HPLC analysis was successfully conducted by using a Hypersil BDS C18 column, eluted with a gradient of methanol-1% acetic acid with a flow rate of 1 mL/min, and detected at 334 nm. Parameters for the validation included linearity, precision, accuracy and limits of detection and quantitation. The developed HPLC method was precise, with relative standard deviation oleifera leaf extracts were 98.50, 98.47 and 98.59%, respectively. The average contents of these compounds in the dried ethanolic extracts of the leaves of M. oleifera collected from different regions of Thailand were 0.081, 0.120 and 0.153% (w/w), respectively. The developed HPLC method was appropriate and practical for the simultaneous analysis of crypto-chlorogenic acid, isoquercetin and astragalin in the leaf extract of M. oleifera. This work is valuable as guidance for the standardization of the leaf extracts and pharmaceutical products of M. oleifera. © The Author [2013]. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  13. HPLC-SPE-NMR for combinatorial biosynthetic investigations – expanding the landscape of diterpene structural diversity

    DEFF Research Database (Denmark)

    Kongstad, Kenneth Thermann; Andersen-Ranberg, Johan; Hamberger, Björn Robert

    In this work, the analytical technique, HPLC-HRMS-SPE-NMR was used for the first time in combination with combinatorial biosynthetic investigations in N. benthamiana. This efficient setup allowed for identification of several diterpene synthase (diTPS) combinations responsible for stereospecific ...

  14. Determination of the sugar content in fruit flavoured drinks by HPLC ...

    African Journals Online (AJOL)

    The remaining 3 fruit flavoured drinks indicated the presence of glucose and sucrose only. The sugar content of some of the drinks calls for caution in children's diet especially with the rise in obesity and dental erosion in tooth enamel associated with sugar sweetened beverages or drinks. Keywords: HPLC; Fruit drinks, ...

  15. HPLC analysis of kaempherol and quercetin derivatives isolated by different extraction techniques from plant matrix.

    Science.gov (United States)

    Skalicka-Woźniak, Krystyna; Szypowski, Janusz; Głowniak, Kazimierz

    2011-01-01

    Soxhlet extraction, ultrasound extraction, and accelerated solvent extraction (ASE), followed by RP-HPLC with a photodiode array detector was used for the determination of flavonoids in fruits of Peucedanum alsaticum. Three compounds were identified: a kaempherol derivative (astragalin), and two quercetin derivatives (quercitrin and hiperoside). The highest extraction yields of the selected compounds were obtained by use of exhaustive ASE.

  16. Development and Validation of a Stability-Indicating RP-HPLC ...

    African Journals Online (AJOL)

    Purpose: To develop a stability indicating RP-HPLC method for a combination drug product containing a high dose of paracetamol (PR) and low doses of domperidone (DM) and tramadol HCL (TR). Methods: The analytes are well separated by a reverse phase column and an isocratic mobile phase consisting of 0.1 %v/v ...

  17. Fast quality screening of vegetable oils by HPLC-thermal lens spectrometric detection

    NARCIS (Netherlands)

    Luterotti, S.; Franko, M.; Bicanic, D.

    2002-01-01

    Isocratic reversed-phase HPLC with thermal lens spectrometric (TLS) detection enabled identification of linseed, olive, sesame, and wheat germ vegetable oils to control the authenticity of the oils based on characteristic carotenoid/carotene profiles. Four characteristic regions of carotenoids

  18. Development and Validation of a RP-HPLC Method for Assay of ...

    African Journals Online (AJOL)

    1Polymer Research Lab, Department of Chemistry, Faculty of Science, 2Department of Pharmaceutics, Faculty of Pharmacy,. King Abdulaziz ... Purpose: To develop and validate a novel reverse phase high performance liquid chromatographic. (RP-HPLC) .... instrument with Eclipse XDB® column 5 µm (4.6 x. 150 mm).

  19. Discrimination of Polish unifloral honeys using overall PTR-MS and HPLC fingerprints combined with chemometrics

    NARCIS (Netherlands)

    Kus, P.M.; Ruth, van S.M.

    2015-01-01

    A total of 62 honey samples of six floral origins (rapeseed, lime, heather, cornflower, buckwheat and black locust) were analysed by means of proton transfer reaction mass spectrometry (PTR-MS) and HPLC-DAD. The data were evaluated by principal component analysis and k-nearest neighbours

  20. Characterization of insulin-loaded liposome using column-switching HPLC.

    Science.gov (United States)

    Ohnishi, Naozumi; Tanaka, Shota; Tahara, Kohei; Takeuchi, Hirofumi

    2015-02-20

    We evaluated the drug-encapsulation state of insulin (INS)-loaded liposome using a novel column-switching HPLC system that can automatically separate unloaded drug from encapsulated drug by hydrophobic interaction. When the INS-loaded liposome was dispersed in water (pH 7.4), the encapsulation efficiency (EE) obtained by the column-switching HPLC system was consistent with that obtained by a conventional ultracentrifugation method. However, the INS-loaded liposome dispersed in 0.1% acetic acid (pH 3.3) showed disagreement between the EEs obtained by both methods. Considering the results of particle size, zeta potential, and transmission electron microscope (TEM) observations, we hypothesized that the column-switching HPLC method was able to distinguish INS adsorbed onto the liposome surface from the encapsulated INS, although an ultracentrifugation method precipitated the adsorbed INS onto the liposome surface along with the encapsulated INS. Therefore, the novel column-switching HPLC system may be a more accurate and useful technique for characterization and optimization of the INS-loaded liposome formulation. Copyright © 2014 Elsevier B.V. All rights reserved.

  1. PHYTOPLANKTON PIGMENT ANALYSIS BY HPLC FOR ASSESSING COMMUNITY COMPOSITION IN THE LAURENTIAN GREAT LAKES

    Science.gov (United States)

    A technique to rapidly assess phytoplankton dynamics is being evaluated for its utility in the Great Lakes. Comparison to traditional microscopic techniques and to more recent in-situ FluoroProbe technology will allow us to determine if HPLC pigment analysis can provide unique a...

  2. HPLC-photodiode array detection analysis of curcuminoids in Curcuma species indigenous to Indonesia

    NARCIS (Netherlands)

    Bos, Rein; Windono, Tri; Woerdenbag, Herman J.; Boersma, Ykelien L.; Koulman, Albert; Kayser, Oliver

    An optimized HPLC method with photodiode array detection was developed and applied to analyse the curcuminoids curcumin, demethoxycurcumin, and bis-demethoxycurcumin in rhizomes of Curcuma mangga Val &. v. Zijp, C. heyneana Val. & v. Zijp, C. aeruginosa Roxb. and C. soloensis Val. (Zingiberaceae),

  3. Determination of organic acids evolution during apple cider fermentation using an improved HPLC analysis method

    NARCIS (Netherlands)

    Zhang, H.; Zhou, F.; Ji, B.; Nout, M.J.R.; Fang, Q.; Zhang, Z.

    2008-01-01

    An efficient method for analyzing ten organic acids in food, namely citric, pyruvic, malic, lactic, succinic, formic, acetic, adipic, propionic and butyric acids, using HPLC was developed. Boric acid was added into the mobile phase to separate lactic and succinic acids, and a post-column buffer

  4. Two Validated HPLC Methods for the Quantification of Alizarin and other Anthraquinones in Rubia tinctorum Cultivars

    NARCIS (Netherlands)

    Derksen, G.C.H.; Lelyveld, G.P.; Beek, van T.A.; Capelle, A.; Groot, de Æ.

    2004-01-01

    Direct and indirect HPLC-UV methods for the quantitative determination of anthraquinones in dried madder root have been developed, validated and compared. In the direct method, madder root was extracted twice with refluxing ethanol-water. This method allowed the determination of the two major native

  5. An optimized method for automated analysis of algal pigments by HPLC

    NARCIS (Netherlands)

    van Leeuwe, M. A.; Villerius, L. A.; Roggeveld, J.; Visser, R. J. W.; Stefels, J.

    2006-01-01

    A recent development in algal pigment analysis by high-performance liquid chromatography (HPLC) is the application of automation. An optimization of a complete sampling and analysis protocol applied specifically in automation has not yet been performed. In this paper we show that automation can only

  6. Determination of epirubicin and its metabolite epirubicinol in saliva and plasma by HPLC

    NARCIS (Netherlands)

    Dodde, WIW; Maring, JG; Hendriks, G; Wachters, FM; Groen, HJM; de Vries, EGE; Uges, DRA

    We present a high-performance liquid chromatography (HPLC) method suitable for the analysis of epirubicin and its metabolite epirubicinol in saliva and plasma. Preparation of saliva and plasma samples was performed by extraction of analytes with a chloroform: 2-propanol mixture (6:1, vol/vol) and

  7. [Identification and Comparison of Constituents of Different Processed Products of Ligubtrum lucidum Fruit by HPLC Fingerprint].

    Science.gov (United States)

    Liang, Xiao; Wu, Peng; Zhang, Xue-lan; Li, Zhuan-mei; Wang, Jun-xiu; Zhang, Qun-qun; Meng, Yan

    2015-11-01

    To identify and compare the constituents in different processed products of Ligubtrum lucidum fruit by HPLC fingerprint, in order to study the changes of chemical constituents before and after processing. HPLC analysis was carried outwith the mobile phase of acetonitrile and 0.1% formic acid in a gradient elution mode. The number of HPLC fingerprint chromatographic peaks and peak area changes in two processed products and the crude product under 240 nm and 280 nm were compared. Then the obtained fingerprint chromatographic peaks were confirmed according to the the standard references. 40 chromatographic peaks were detected from Ligustrum lucidum fruit, of which 18 chromatographic peaks were confirmed, including eleven iridoids, five phenethyl alcohols, one flavonoid and one aldehyde. 38 chromatographic peaks were detected from both steaming with wine product and the steamed product, of which 15 chromatographic peaks were confirmed, including seven iridoids, five phenethyl alcohols, one flavonoid, one aldehyde and one organic acid. There was a significant difference of fingerprint among crude Ligustrum lucidum fruit and its two processed products, but little difference between steaming with wine product and the steamed product. HPLC fingerprint of the steaming with wine product and the steamed product of Ligustrum lucidum fruit are similar while the changes on chemical composition and the content in steaming with wine product and steamed product of Ligustrum lucidum fruit are remarkable.

  8. Method for Vanadium Speciation in Aqueous Samples by HPLC-ICP ...

    African Journals Online (AJOL)

    Method for Vanadium Speciation in Aqueous Samples by HPLC-ICP-OES. M Hu, PP Coetzee. Abstract. A method for vanadium speciation is proposed. The method uses a low concentration eluent, 10 mmol L–1 EDTA and 14 mmol L–1 sodium carbonate, for the ion chromatographic separation of vanadium species at a ...

  9. Simultaneous analysis of 17 diuretics in dietary supplements by HPLC and LC-MS/MS.

    Science.gov (United States)

    Woo, H; Kim, J W; Han, K M; Lee, J H; Hwang, I S; Lee, J H; Kim, J; Kweon, S J; Cho, S; Chae, K R; Han, S Y; Kim, J

    2013-01-01

    In order to test health foods for illegally added diuretics for weight loss, we developed simple, rapid, selective, and sensitive methods using HPLC and LC-MS/MS for the simultaneous analysis of 17 diuretics in dietary supplements. HPLC conditions were set with a Capcell-pak C18, using a mobile phase consisting of gradient conditions, UV detection at 254 nm and validated for linearity (r(2)> 0.999), precision (CV ≤ 3%), recoveries (90.4-102.8%) and reproducibility. Identification and quantification of 17 diuretics were accomplished by ion-spray LC-MS/MS using multiple reaction monitoring (MRM). The chromatographic separation was carried out under the reversed-phase mechanism on an HSS-T3 column. The LC-MS/MS method was validated for linearity (r(2)> 0.99) and precision (CV Diuretics were not detected in all samples. Extraction recovery was also investigated and the extraction recoveries in different formulations were from 88% to 110% and from 81% to 116% using HPLC and LC-MS/MS, respectively. There was no significant difference in recoveries in the type of dietary supplements. Based on this result, the developed methods to monitor illegal drug adulterations in dietary supplements using HPLC and LC-MS/MS are simple, fast and reliable. Therefore, it is applicable to routine drug-adulteration screening.

  10. RP-HPLC-DAD determination of quercetin, luteolin and apigenin in ...

    African Journals Online (AJOL)

    HPLC methods have been reported to quantify isolated flavonoids or these compounds in complex biological matrices, such as Chinese herbal drugs products from factories. This work was developed to separate quercetin, luteolin and apigenin and to quantify them in extractive solutions from Marchantia covoluta. The main ...

  11. GC-MS and HPLC analysis of crude extracts of stem bark of ...

    African Journals Online (AJOL)

    The present investigation was carried out to characterize the chemical profile of the crude extract of stem bark of Adansonia digitata using GC-MS and HPLC analysis The plant stem bark were extracted using three solvents, the crude extracts of each solvent were characterized using Gas chromatography mass spectrometry ...

  12. Application of HPLC capacity coefficients to characterize the sorption of polycyclic aromatic compounds to humic acid

    DEFF Research Database (Denmark)

    Nielsen, T.; Helweg, C.; Siigur, K.

    1997-01-01

    The sorption coefficients to humic acid of 46 PAC having a wide range in polarity were compared with the capacity coefficients of the PAC to a non-polar HPLC column material (ODS) and a polar one (Diol). It is shown that polar interactions contribute to the sorption of polar PAC in addition...

  13. Analysis of several irdoid and indole precursors of terpenoid indole alkaloids with a single HPLC run

    DEFF Research Database (Denmark)

    Dagnino, Denise; Schripsema, Jan; Verpoorte, Robert

    1996-01-01

    An isocratic HPLC system is described which allows the separation of the iridoid and indole precursors of terpenoid indole alkaloids, which are present in a single crude extract. The system consists of a column of LiChrospher 60 RP select B 5 my, 250x4 mm (Merck) with an eluent of 1 % formic acid...

  14. Literatuuronderzoek naar HPLC-methoden voor de bepaling van vitamine B1 en B2

    NARCIS (Netherlands)

    Hollman, P.

    1986-01-01

    Analyses van vitamine B1 en B2 worden door de afdeling Additieven/Micronutrienten veelvuldig uitgevoerd in zeer diverse produkten. Dit stelt hoge eisen aan de selektiviteit van de gebruikte methoden. Onlangs werd dan ook HPLC geïntroduceerd voor de analyse van vitamine B1 en B2. Op basis van een

  15. Extraction and Purification of Glucoraphanin by Preparative High-Performance Liquid Chromatography (HPLC)

    Science.gov (United States)

    Lee, Iris; Boyce, Mary C.

    2011-01-01

    A student activity that focuses on the isolation of glucoraphanin from broccoli using preparative high-performance liquid chromatography (HPLC) is presented here. Glucoraphanin is a glucosinolate, whose byproducts are known to possess anticancer properties. It is present naturally at high levels in broccoli and other "Brassica" vegetables. This…

  16. Development and validation of a RP-HPLC method for assay of ...

    African Journals Online (AJOL)

    Purpose: To develop and validate a novel reverse phase high performance liquid chromatographic (RP-HPLC) method for the quantification of atorvastatin in thermosensitive hydrogel-based nanocrystal formulation. Method: Chromatographic identification was achieved on C18 (5 μm) column using acetonitrile and 0.025 M ...

  17. A Decomposition Model for HPLC-DAD Data Set and Its Solution by Particle Swarm Optimization

    Directory of Open Access Journals (Sweden)

    Lizhi Cui

    2014-01-01

    Full Text Available This paper proposes a separation method, based on the model of Generalized Reference Curve Measurement and the algorithm of Particle Swarm Optimization (GRCM-PSO, for the High Performance Liquid Chromatography with Diode Array Detection (HPLC-DAD data set. Firstly, initial parameters are generated to construct reference curves for the chromatogram peaks of the compounds based on its physical principle. Then, a General Reference Curve Measurement (GRCM model is designed to transform these parameters to scalar values, which indicate the fitness for all parameters. Thirdly, rough solutions are found by searching individual target for every parameter, and reinitialization only around these rough solutions is executed. Then, the Particle Swarm Optimization (PSO algorithm is adopted to obtain the optimal parameters by minimizing the fitness of these new parameters given by the GRCM model. Finally, spectra for the compounds are estimated based on the optimal parameters and the HPLC-DAD data set. Through simulations and experiments, following conclusions are drawn: (1 the GRCM-PSO method can separate the chromatogram peaks and spectra from the HPLC-DAD data set without knowing the number of the compounds in advance even when severe overlap and white noise exist; (2 the GRCM-PSO method is able to handle the real HPLC-DAD data set.

  18. Novel assay of antibacterial components in manuka honey using lucigenin-chemiluminescence-HPLC

    Energy Technology Data Exchange (ETDEWEB)

    Karasawa, Koji, E-mail: koji180@pharm.showa-u.ac.jp; Haraya, Shiomi; Okubo, Sachie; Arakawa, Hidetoshi

    2017-02-15

    Five components (hydrogen peroxide, methylglyoxal, dihydroxyacetone, fructose and glucose) of New Zealand manuka honey (Leptospermum scoparium) were analyzed using lucigenin chemiluminescence high-performance liquid chromatography (lucigenin-CL-HPLC). We focused on active oxygen species produced from the components in order to easily detect these five components contained in manuka honey. H{sub 2}O{sub 2} and O{sub 2}{sup −} generated from these components were identified by lucigenin-CL and electron spin resonance (ESR), and the bactericidal effect of ROS was confirmed using E. coli. The previously reported assays for Manuka honey components have low specificities and require complicated preprocessing methods. As our results, the detection and identification of these components were possible within 30 min in lucigenin-CL-HPLC system, without any special treatment. It is considered that lucigenin-CL-HPLC is useful for the quality control and the analysis of various honey. - Highlights: • Antibacterial components in manuka honey by HPLC with lucigenin-CL. • Five antibacterial compounds measured via generation of reactive oxygen species. • Simple, sensitive and useful for quality control and analysis of antibacterial honey.

  19. Validation of chromatographic methods: an experiment using HPLC and Green Chemistry in methylxanthines determination

    OpenAIRE

    Nádia Machado de Aragão; Márcia Cristina da Cunha Veloso; Jailson Bittencourt de Andrade

    2009-01-01

    The validation of analytical methods is an important step in quality control. The main objective of this study is to propose an HPLC experiment to verify the parameters of validation of chromatographic methods, based on green chemistry principles, which can be used in experimental courses of chemistry and related areas.

  20. Melanin determination by high performance liquid chromatography (HPLC) for K. marxianus

    Science.gov (United States)

    Ultraviolet light (UV) mutated K. marxianus was found to turn dark brown during a growth assay. This brown color was hypothesized to be melanin overproduction influenced by the UV exposure. Cell cultures were oxidized and HPLC analyzed to determine melanin concentrations. The resulting melanin con...

  1. 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.

  2. Determination of Trace Elements in Uranium by HPLC-ID-ICP-MS: NTNFC Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Manard, Benjamin Thomas [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Wylie, Ernest Miller II [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Xu, Ning [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Tandon, Lav [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-10-19

    This report covers the FY 16 effort for the HPLC-ID-ICP-MS methodology 1) sub-method validation for the group I&II elements, 2) sub-method stood-up and validation for REE, 3) sub-method development for the transition element, and 4) completion of a comprehensive SOP for three families of elements.

  3. Using HPLC-Mass Spectrometry to Teach Proteomics Concepts with Problem-Based Techniques

    Science.gov (United States)

    Short, Michael; Short, Anne; Vankempen, Rachel; Seymour, Michael; Burnatowska-Hledin, Maria

    2010-01-01

    Practical instruction of proteomics concepts was provided using high-performance liquid chromatography coupled with a mass selective detection system (HPLC-MS) for the analysis of simulated protein digests. The samples were prepared from selected dipeptides in order to facilitate the mass spectral identification. As part of the prelaboratory…

  4. Development and Validation of a RP-HPLC Method for the ...

    African Journals Online (AJOL)

    Purpose: To develop and validate a sensitive HPLC method for the separation and simultaneous estimation of two ingredients in a composition comprising of rifampicin and a flavonoid glycoside (an enhancer of oral bioavailability of rifampicin). Methods: Reverse phase (RP) chromatographic separation and estimation was ...

  5. Competitive Nitration of Benzene-Fluorobenzene and Benzene-Toluene Mixtures: Orientation and Reactivity Studies Using HPLC

    Science.gov (United States)

    Blankespoor, Ronald L.; Hogendoorn, Stephanie; Pearson, Andrea

    2007-01-01

    The reactivity and orientation effects of a substituent are analyzed by using HPLC to determine the competitive nitration of the benzene-toluene and benzene-fluorobenzene mixtures. The results have shown that HPLC is an excellent instrumental method to use in analyzing these mixtures.

  6. The first use of a HPLC system at a Louisiana Sugarcane Factory: What it can do for you

    Science.gov (United States)

    Alma Plantation sugarcane factory established and operated the first High Performance Liquid Chromatography (HPLC) system in Louisiana in 2015. Although many HPLC systems exist, the factory opted for a ThermoFisherTM ion chromatography (anion exchange) system with integrated pulsed amperometric det...

  7. Kinetic hysteresis in collagen folding.

    Science.gov (United States)

    Mizuno, Kazunori; Boudko, Sergei P; Engel, Jürgen; Bächinger, Hans Peter

    2010-06-16

    The triple helix of collagen shows a steep unfolding transition upon heating, whereas less steep and more gradual refolding is observed upon cooling. The shape of the hysteresis loop depends on the rate of temperature change as well as the peptide concentration. Experimental heating and cooling rates are usually much faster than rates of unfolding and refolding. In this work, collagen model peptides were used to study hysteresis quantitatively. Their unfolding and refolding profiles were recorded at different heating and cooling rates, and at different peptide concentrations. Data were fitted assuming kinetic mechanisms in which three chains combine to a helix with or without an intermediate that acts as a nucleus. A quantitative fit was achieved with the same kinetic model for the forward and backward reactions. Transitions of exogenously trimerized collagen models were also analyzed with a simplified kinetic mechanism. It follows that true equilibrium transitions can only be measured at high concentrations of polypeptide chains with slow scanning rates, for example, 0.1 degrees C/h at 0.25 mM peptide concentration of (Gly-Pro-Pro)(10). (Gly-Pro-4(R)Hyp)(10) folds approximately 2000 times faster than (Gly-Pro-Pro)(10). This was explained by a more stable nucleus, whereas the rate of propagation was almost equal. The analysis presented here can be used to derive kinetic and thermodynamic data for collagenous and other systems with kinetically controlled hysteresis. (c) 2010 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  8. HPLC/ICP-MS in combination with "reverse" online isotope dilution in drug metabolism studies.

    Science.gov (United States)

    Meermann, Björn; Hulstaert, Anne; Laenen, Aline; Van Looveren, Cis; Vliegen, Maarten; Cuyckens, Filip; Vanhaecke, Frank

    2012-03-06

    During the development of a new drug compound, its metabolism needs to be unraveled. For quantification of the metabolites formed, the drug under investigation is traditionally synthesized with a radiolabel ((14)C or (3)H) and the metabolites present in different matrixes (blood, urine, feces) upon drug administration are determined by means of high-performance liquid chromatography (HPLC) coupled to radiodetection. This approach allows for quantification of the metabolites formed and enables a straightforward distinction between exogenous (i.e., drug-related) and endogenous species (as only the radiolabeled species are detected). However, in some cases, the use of a radiolabeled compound in human in vivo studies is not advisible, e.g., for drug compounds or their metabolites showing a long plasma or tissue half-life. In cases where the candidate drug molecule contains an element detectable by means of inductively coupled plasma mass spectrometry (ICP-MS), HPLC/ICP-MS is a promising alternative approach. However, the method lacks specificity when a distinction between drug-related species and endogenous compounds containing the same target element needs to be accomplished. As a result, we have developed an HPLC/ICP-MS-based method combined with "reverse" online isotope dilution ("reverse" online ID) for metabolite quantification. The methodology was evaluated by the analysis of feces samples from rats dosed with a (81)Br-labeled drug compound. The method allows for both (i) valid quantification of the drug metabolites and (ii) distinction among endogenous, exogenous, and "mixed" species, based on their isotopic "fingerprint". A good repeatability (relative standard deviation of 4.2%) and limit of detection (0.35 mg of drug compound L(-1) of feces extract), of the same order of magnitude as those observed for "normal" online ID HPLC/ICP-MS and HPLC/radiodetection, were achieved.

  9. Determination of Bortezomib in API Samples Using HPLC: Assessment of Enantiomeric and Diastereomeric Impurities.

    Science.gov (United States)

    Kamalzadeh, Zahra; Babanezhad, Esmaeil; Ghaffari, Solmaz; Mohseni Ezhiyeh, Alireza; Mohammadnejad, Mahdieh; Naghibfar, Mehdi; Bararjanian, Morteza; Attar, Hossein

    2017-08-01

    A new, normal phase high performance liquid chromatography (NP-HPLC) method was developed for separation of Bortezomib (BZB) enantiomers and quantitative determination of (1S,2R)-enantiomer of BZB in active pharmaceutical ingredient (API) samples. The developed method was validated based on International Conference on Harmonisation (ICH) guidelines and it was proved to be accurate, precise and robust. The obtained resolution (RS) between the enantiomers was more than 2. The calibration curve for (1S,2R)-enantiomer was found to be linear in the concentration range of 0.24-5.36 mg/L with regression coefficient (R2) of 0.9998. Additionally, the limit of detection (LOD) and limit of quantification (LOQ) were 0.052 and 0.16 mg/L, respectively. Also, in this study, a precise, sensitive and robust gradient reversed-phase HPLC (RP-HPLC) method was developed and validated for determination of BZB in API samples. The detector response was linear over the concentration range of 0.26-1110.5 mg/L. The values of R2, LOD and LOQ were 0.9999, 0.084 and 0.25 mg/L, respectively. For both NP-HPLC and RP-HPLC methods, all of the RSD (%) values obtained in the precision study were 2,000 and RS > 2.0. The performance of two common integration methods of valley to valley and drop perpendicular for drawing the baseline between two adjacent peaks were investigated for the determination of diastereomeric impurity (Imp-D) in the BZB-API samples. The results showed that the valley to valley method outperform the drop perpendicular method for calculation of Imp-D peak areas. Therefore, valley to valley method was chosen for peak integration. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  10. Validation of creatinine assays utilizing HPLC and IDMS traceable standards in sera of children.

    Science.gov (United States)

    Schwartz, George J; Kwong, Tai; Erway, Brian; Warady, Bradley; Sokoll, Lori; Hellerstein, Stanley; Dharnidharka, Vikas; Furth, Susan; Muñoz, Alvaro

    2009-01-01

    The purpose of this study was to validate serum creatinine (SCr) concentrations assayed in the Central Biochemistry Laboratory of the National Institutes of Health (NIH)-funded Chronic Kidney Disease in Children (CKiD) study utilizing an enzymatic assay (Siemens Advia 2400) against a method traceable to reference isotope dilution mass spectroscopy (IDMS) developed by the National Institute of Standards and Technology (NIST). High-performance liquid chromatography (HPLC) measured SCr after external validation utilizing IDMS-based standard reference materials. Sera from the first 201 subjects enrolled in CKiD were analyzed and compared for creatinine concentration by enzymatic and HPLC methods. Fifty "normal" pediatric sera were subsequently analyzed. Finally, a "pediatric" reference standard was prepared and examined for accuracy and precision. Enzymatic SCr concentrations (median 1.4 mg/dl) of CKiD subjects were well correlated with HPLC (r = 0.984) but were slightly higher (+7%; p < 0.001). Agreement was poorer at lower SCr (median 0.4 mg/dl) when using samples from normal children and the "pediatric" reference standard. However, the Roche enzymatic assay was comparable with HPLC in accuracy and precision. Referring physicians should be aware of the accuracy and reproducibility of their laboratory's SCr assay. Our enzymatic assay agreed well with HPLC in CKiD subjects with elevated SCr. We suggest that NIST develop a pediatric SCr standard reference material for use by assay manufacturers to improve accuracy and precision of assays at the low SCr levels observed in most pediatric patients.

  11. Robustness Analysis of Kinetic Structures

    DEFF Research Database (Denmark)

    Kirkegaard, Poul Henning; Sørensen, John Dalsgaard

    2009-01-01

    The present paper considers robustness of kinetic structures. Robustness of structures has obtained a renewed interest due to a much more frequent use of advanced types of structures with limited redundancy and serious consequences in case of failure. Especially for these types of structural syst...... systems, it is of interest to investigate how robust the structures are, or what happens if a structural element is added to or removed from the original structure. The present paper discusses this issue for kinetic structures in architecture.......The present paper considers robustness of kinetic structures. Robustness of structures has obtained a renewed interest due to a much more frequent use of advanced types of structures with limited redundancy and serious consequences in case of failure. Especially for these types of structural...

  12. Kinetic theory and transport phenomena

    CERN Document Server

    Soto, Rodrigo

    2016-01-01

    This textbook presents kinetic theory, which is a systematic approach to describing nonequilibrium systems. The text is balanced between the fundamental concepts of kinetic theory (irreversibility, transport processes, separation of time scales, conservations, coarse graining, distribution functions, etc.) and the results and predictions of the theory, where the relevant properties of different systems are computed. The book is organised in thematic chapters where different paradigmatic systems are studied. The specific features of these systems are described, building and analysing the appropriate kinetic equations. Specifically, the book considers the classical transport of charges, the dynamics of classical gases, Brownian motion, plasmas, and self-gravitating systems, quantum gases, the electronic transport in solids and, finally, semiconductors. Besides these systems that are studied in detail, concepts are applied to some modern examples including the quark–gluon plasma, the motion of bacterial suspen...

  13. Phosphate kinetic models in hemodialysis

    DEFF Research Database (Denmark)

    Laursen, Sisse Heiden; Vestergaard, Peter; Hejlesen, Ole K.

    2018-01-01

    BACKGROUND: Understanding phosphate kinetics in dialysis patients is important for the prevention of hyperphosphatemia and related complications. One approach to gain new insights into phosphate behavior is physiologic modeling. Various models that describe and quantify intra- and/or interdialytic...... phosphate kinetics have been proposed, but there is a dearth of comprehensive comparisons of the available models. The objective of this analysis was to provide a systematic review of existing published models of phosphate metabolism in the setting of maintenance hemodialysis therapy. STUDY DESIGN......: Systematic review. SETTING & POPULATION: Hemodialysis patients. SELECTION CRITERIA FOR STUDIES: Studies published in peer-reviewed journals in English about phosphate kinetic modeling in the setting of hemodialysis therapy. PREDICTOR: Modeling equations from specific reviewed studies. OUTCOMES: Changes...

  14. Selected readings in chemical kinetics

    CERN Document Server

    Back, Margaret H

    2013-01-01

    Selected Readings in Chemical Kinetics covers excerpts from 12 papers in the field of general and gas-phase kinetics. The book discusses papers on the laws of connexion between the conditions of a chemical change and its amount; on the reaction velocity of the inversion of the cane sugar by acids; and the calculation in absolute measure of velocity constants and equilibrium constants in gaseous systems. The text then tackles papers on simple gas reactions; on the absolute rate of reactions in condensed phases; on the radiation theory of chemical action; and on the theory of unimolecular reacti

  15. Chemical kinetics and combustion modeling

    Energy Technology Data Exchange (ETDEWEB)

    Miller, J.A. [Sandia National Laboratories, Livermore, CA (United States)

    1993-12-01

    The goal of this program is to gain qualitative insight into how pollutants are formed in combustion systems and to develop quantitative mathematical models to predict their formation rates. The approach is an integrated one, combining low-pressure flame experiments, chemical kinetics modeling, theory, and kinetics experiments to gain as clear a picture as possible of the process in question. These efforts are focused on problems involved with the nitrogen chemistry of combustion systems and on the formation of soot and PAH in flames.

  16. Chemical kinetics and reaction dynamics

    CERN Document Server

    Houston, Paul L

    2006-01-01

    This text teaches the principles underlying modern chemical kinetics in a clear, direct fashion, using several examples to enhance basic understanding. It features solutions to selected problems, with separate sections and appendices that cover more technical applications.Each chapter is self-contained and features an introduction that identifies its basic goals, their significance, and a general plan for their achievement. This text's important aims are to demonstrate that the basic kinetic principles are essential to the solution of modern chemical problems, and to show how the underlying qu

  17. Non-kinetic capabilities: complementing the kinetic prevalence to targeting

    NARCIS (Netherlands)

    Ducheine, P.A.L.; Ducheine, P.A.L.; Schmitt, M.N.; Osinga, F.P.B.

    2016-01-01

    Targeting is used in military doctrine to describe a military operational way, using (military) means to influence a target (or addressee) in order to achieve designated political and/or military goals. The four factors italicized are used to analyse non-kinetic targeting, thereby complementing our

  18. Non-kinetic capabilities: complementing the kinetic prevalence to targeting

    NARCIS (Netherlands)

    Ducheine, P.

    2014-01-01

    Targeting is used in military doctrine to describe a military operational way, using (military) means to influence a target (or addressee) in order to achieve designated political and/or military goals. The four factors italicized are used to analyse non-kinetic targeting, complementing our

  19. Using a simple HPLC approach to identify the enzymatic products of UTL-5g, a small molecule TNF-α inhibitor, from porcine esterase and from rabbit esterase.

    Science.gov (United States)

    Swartz, Kenneth; Zhang, Yiguan; Valeriote, Frederick; Chen, Ben; Shaw, Jiajiu

    2013-12-01

    UTL-5g is a novel small-molecule chemoprotector that lowers hepatotoxicity, nephrotoxicity, and myelotoxicity induced by cisplatin through TNF-α inhibition among other factors. As a prelude to investigating the metabolites of UTL-5g, we set out to identify the enzymatic products of UTL-5g under the treatment of both porcine liver esterase (PLE) and rabbit liver esterase (RLE). First, a number of mixtures made by UTL-5g and PLE were incubated at 25°C. At predetermined time points, individual samples were quenched by acetonitrile, vortexed, and centrifuged. The supernatants were then analyzed by reversed-phase HPLC (using a C18 column). The retention times and UV/vis spectra of individual peaks were compared to those of UTL-5g and its two postulated enzymatic products; thus the enzymatic products of UTL-5g were tentatively identified. Secondly, a different HPLC method (providing different retentions times) was used to cross-check and to confirm the identities of the two enzymatic products. Based on the observations, it was concluded that under the treatment of PLE, the major enzymatic products of UTL-5g were 5-methyliosxazole-3-carboxylic acid (ISOX) and 2,4-dichloroaniline (DCA). Treatment of UTL-5g by RLE also provided the same enzymatic products of UTL-5g from esterase. These results indicate that the peptide bond in UTL-5g was cleaved by PLE/RLE. Michaelis-Menten kinetics showed that the Km values of UTL-5g were 2.07mM with PLE and 0.37mM with RLE indicating that UTL-5g had a higher affinity with RLE. In summary, by a simple HPLC approach, we have concluded that the peptide bond in UTL-5g was cleaved by esterase from either porcine liver or rabbit liver in vitro and afforded DCA (at a mole ratio of 1:1) and ISOX. However, further studies are needed in order to determine whether UTL-5g is metabolized by microsomal enzymes to produce ISOX and DCA. Copyright © 2013 Elsevier B.V. All rights reserved.

  20. The effect of re-dissolution solvents and HPLC columns on the analysis of mycosporine-like amino acids in the eulittoral macroalgae and

    National Research Council Canada - National Science Library

    Karsten, Ulf; Escoubeyrou, Karine; Charles, François

    2009-01-01

    .... Therefore pure methanol, distilled water and HPLC eluent were evaluated as re-dissolution solvent for dried and extracts, which were subsequently analyzed on three reversed-phase C8 and C18 HPLC columns...

  1. Estimation of the limit of detection with a bootstrap-derived standard error by a partly non-parametric approach. Application to HPLC drug assays

    DEFF Research Database (Denmark)

    Linnet, Kristian

    2005-01-01

    Bootstrap, HPLC, limit of blank, limit of detection, non-parametric statistics, type I and II errors......Bootstrap, HPLC, limit of blank, limit of detection, non-parametric statistics, type I and II errors...

  2. Kinetics study of hydrochlorothiazide lactose liquid state interaction using conventional isothermal arrhenius method under basic and neutral conditions

    Directory of Open Access Journals (Sweden)

    Faranak Ghaderi

    Full Text Available ABSTRACT The Maillard reaction of hydrochlorothiazide (HCTZ and lactose has been previously demonstrated in pharmaceutical formulations. In this study, the activation energy of - hydrohlorothiazide and lactose interaction in the liquid state was ascertained under basic and neutral conditions. Conventional isothermal High Performance Liquid Chromatography (HPLC technique was employed to ascertain the kinetic parameters using Arrhenius method. Results: The activation energy obtained was 82.43 and 100.28 kJ/mol under basic and neutral conditions, respectively. Consequently, it can be inferred that Maillard reaction is significantly affected by pH, which can be used as a control factor whenever the reaction potentially occurs.

  3. Kinetic energy equations for the average-passage equation system

    Science.gov (United States)

    Johnson, Richard W.; Adamczyk, John J.

    1989-01-01

    Important kinetic energy equations derived from the average-passage equation sets are documented, with a view to their interrelationships. These kinetic equations may be used for closing the average-passage equations. The turbulent kinetic energy transport equation used is formed by subtracting the mean kinetic energy equation from the averaged total instantaneous kinetic energy equation. The aperiodic kinetic energy equation, averaged steady kinetic energy equation, averaged unsteady kinetic energy equation, and periodic kinetic energy equation, are also treated.

  4. Bicarbonate kinetics in Indian males

    Indian Academy of Sciences (India)

    We have studied the recovery of tracer-labelled bicarbonate using a bolus administration model, and further characterized kinetics of bicarbonate using a three-compartment model, to assess which compartmental fluxes changed during the change from a fasted state to fed state. Recovery of bicarbonate was lower at 69% ...

  5. An equilibrium and kinetic modeling

    African Journals Online (AJOL)

    SERVER

    2007-06-18

    Jun 18, 2007 ... The Langmuir and Freundlich adsorption models fitted well with the equilibrium data of the process studied. ... followed the first order rate expression. Key words: Penicillin-G wastewater, Phanerochate chrysosporium, equilibrium, kinetic study. ... Ammonia-nitrogen (mg/l). 300 - 500. Total phosphate (mg/l).

  6. KINETIC SPECTROPHOTOMETRIC DETERMINATION OF SOME ...

    African Journals Online (AJOL)

    Preferred Customer

    (KMnO4) in alkaline medium (NaOH). The intensity of the color was increased with time and therefore, a kinetically based method was developed for the spectrophotometric determination of these drugs in pharmaceutical formulations. The absorbance of the oxidation product remains stable for at least 8.0 hours.

  7. Chemical kinetics on extrasolar planets.

    Science.gov (United States)

    Moses, Julianne I

    2014-04-28

    Chemical kinetics plays an important role in controlling the atmospheric composition of all planetary atmospheres, including those of extrasolar planets. For the hottest exoplanets, the composition can closely follow thermochemical-equilibrium predictions, at least in the visible and infrared photosphere at dayside (eclipse) conditions. However, for atmospheric temperatures approximately planets.

  8. Robustness Analysis of Kinetic Structures

    DEFF Research Database (Denmark)

    Kirkegaard, Poul Henning; Sørensen, John Dalsgaard

    2009-01-01

    Kinetic structures in architecture follows a new trend which is emerging in responsive architecture coined by Nicholas Negroponte when he proposed that architecture may benefit from the integration of computing power into built spaces and structures, and that better performing, more rational...

  9. Kinetics of Bio-Reactions

    DEFF Research Database (Denmark)

    Villadsen, John

    2015-01-01

    his chapter predicts the specific rates of reaction by means of a mathematical expression, the kinetics of the reaction. This expression can be derived through a mechanistic interpretation of an enzymatically catalyzed reaction, but it is essentially of empirical nature for cell reactions. The mo...

  10. Kinetics of borided gear steels

    Indian Academy of Sciences (India)

    source used, boriding temperature, treatment time, and properties of the borided material (Sahin. & Meric 2002 ... The boriding heat treatment was carried out in solid medium containing an Ekabor-II ..... 2007 Growth kinetics of boride layers on iron-chromium alloys and their dry abrasive wear resistance,. Materials Science ...

  11. Solving Simple Kinetics without Integrals

    Science.gov (United States)

    de la Pen~a, Lisandro Herna´ndez

    2016-01-01

    The solution of simple kinetic equations is analyzed without referencing any topic from differential equations or integral calculus. Guided by the physical meaning of the rate equation, a systematic procedure is used to generate an approximate solution that converges uniformly to the exact solution in the case of zero, first, and second order…

  12. Thermodynamic basis for cluster kinetics

    DEFF Research Database (Denmark)

    Hu, Lina; Bian, Xiufang; Qin, Xubo

    2006-01-01

    Due to the inaccessibility of the supercooled region of marginal metallic glasses (MMGs) within the experimental time window, we study the cluster kinetics above the liquidus temperature, Tl, to acquire information on the fragility of the MMG systems. Thermodynamic basis for the stability...

  13. Superconductivity by kinetic energy saving?

    NARCIS (Netherlands)

    Van der Marel, D; Molegraaf, HJA; Presura, C; Santoso, [No Value; Hewson, AC; Zlatic,

    2003-01-01

    A brief introduction is given in the generic microscopic framework of superconductivity. The consequences for the temperature dependence of the kinetic energy, and the correlation energy are discussed for two cases: The BCS scenario and the non-Fermi liquid scenario. A quantitative comparison is

  14. Deuterium Exchange Kinetics by NMR.

    Science.gov (United States)

    Roper, G. C.

    1985-01-01

    Describes a physical chemistry experiment which allows such concepts as kinetics, catalysis, isotope shifts, coupling constants, and the use of nuclear magnetic resonance (NMR) for quantitative work to be covered in the same exercise. Background information, experimental procedures used, and typical results obtained are included. (JN)

  15. Kinetic studies of cellulose enzymatic hydrolysis from pretreated corn cob

    Science.gov (United States)

    Stevanie, Jeannie; Kartawiria, Irvan; Abimanyu, Haznan

    2017-01-01

    Successful utilization of corn cob biomass as raw material in bioethanol production is depending on the hydrolysis process where high level of β-cellulose is converted into glucose. Enzymatic hydrolysis is the common process for this purpose. This study is focusing on the evaluation of hydrolysis of pre-treated corn cob using Novozymes Cellic ® C-Tec2 and H-Tec2 enzymes to obtain the optimum reaction condition and its general reaction kinetics. The corn cob used was pretreated using 10% of NaOH solution. Hydrolysis reactions were conducted in 250 ml Erlenmeyer flask for 72 hour using mixture of C-Tec2 and H-Tec2 enzymes at the fixed ratio of 5:1 and glucose concentration were measured using HPLC. Reaction temperature of 40°C and quantity of 0.5 ml enzyme solution per gram substrate gives the highest reaction rate (0.0123 gram of glucose/gram sample.h) with the glucose yield being 0.089 g glucose/ g substrate. Total conversion of cellulose observed was 11.91 %. Corn cob hydrolysis using C-Tec2 and H-Tec2 enzymes also result in xylose (0.0202 g/g substrate), which can also contribute to bioethanol productivity in further fermentation process. The reaction is following zero order kinetics for the first 8 hours and reaches maximum yield within 10 hours; significantly shorter compared to previous studies of cellulosic material hydrolysis that may take up to 72 hour to complete. Prolonging the hydrolysis of pre-treated corn cob more than 24 hour gives no significant increase in glucose conversion and yield. Hydrolysis temperature range of 40°C to 60°C is in accordance with the manufacturer recommendation for the purpose; however the decrease of reaction rate is observable at temperature 50°C or higher.

  16. Identification and Analysis of Amygdalin, Neoamygdalin and Amygdalin Amide in Different Processed Bitter Almonds by HPLC-ESI-MS/MS and HPLC-DAD.

    Science.gov (United States)

    Xu, Shuya; Xu, Xinfang; Yuan, Shaoxiong; Liu, Huan; Liu, Mengnan; Zhang, Ying; Zhang, Hui; Gao, Yan; Lin, Ruichao; Li, Xiangri

    2017-08-30

    Processing is a traditional pharmacy technology based on traditional Chinese medicine theory. The traditional Chinese medicine (TCM) ingredients should be processed before being used as a medicine. Processed bitter almonds are widely used in the clinic in TCM for the treatment of cough and asthma. In this work the amygdalin profile of three producing areas in China was determined, with respect to three differently processed bitter almond products: raw, stir-fried and scalded. Identification of the compounds was done by using high performance liquid chromatography coupled to electrospray ionization mass spectrometry (HPLC-ESI-MS/MS). Results indicated that amygdalin, neoamygdalin and amygdalin amide were identified in the different processed bitter almonds. Meanwhile, amygdalin was used as a standard to calculate the quantification of amygdalin and the concentration ratio of neoamygdalin and total amygdalin by HPLC-DAD. The data suggested that composition of amygdalin isomers in bitter almonds was influenced by the processing method. It also gives a new understanding of the processing principle of bitter almonds. Moreover, the classification of different processed bitter almonds can be achieved on the basis of amygdalin isomers levels.

  17. Quality Evaluation and Chemical Markers Screening of Salvia miltiorrhiza Bge. (Danshen Based on HPLC Fingerprints and HPLC-MSn Coupled with Chemometrics

    Directory of Open Access Journals (Sweden)

    Wenyi Liang

    2017-03-01

    Full Text Available Danshen, the dried root of Salvia miltiorrhiza Bge., is a widely used commercially available herbal drug, and unstable quality of different samples is a current issue. This study focused on a comprehensive and systematic method combining fingerprints and chemical identification with chemometrics for discrimination and quality assessment of Danshen samples. Twenty-five samples were analyzed by HPLC-PAD and HPLC-MSn. Forty-nine components were identified and characteristic fragmentation regularities were summarized for further interpretation of bioactive components. Chemometric analysis was employed to differentiate samples and clarify the quality differences of Danshen including hierarchical cluster analysis, principal component analysis, and partial least squares discriminant analysis. Consistent results were that the samples were divided into three categories which reflected the difference in quality of Danshen samples. By analyzing the reasons for sample classification, it was revealed that the processing method had a more obvious impact on sample classification than the geographical origin, it induced the different content of bioactive compounds and finally lead to different qualities. Cryptotanshinone, trijuganone B, and 15,16-dihydrotanshinone I were screened out as markers to distinguish samples by different processing methods. The developed strategy could provide a reference for evaluation and discrimination of other traditional herbal medicines.

  18. Kinetic investigation of wood pyrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Thurner, F.; Mann, U.; Beck, S. R.

    1980-06-01

    The objective of this investigation was to determine the kinetics of the primary reactions of wood pyrolysis. A new experimental method was developed which enabled us to measure the rate of gas, tar, and char production while taking into account the temperature variations during the wood heating up. The experimental method developed did not require any sophisticated instruments. It facilitated the collection of gas, tar and residue (unreacted wood and char) as well as accurate measurement of the temperature inside the wood sample. Expressions relating the kinetic parameters to the measured variables were derived. The pyrolysis kinetics was investigated in the range of 300 to 400/sup 0/C at atmospheric pressure and under nitrogen atmosphere. Reaction temperature and mass fractions of gas, tar, and residue were measured as a function of time. Assuming first-order reactions, the kinetic parameters were determined using differential method. The measured activation energies of wood pyrolysis to gas, tar, and char were 88.6, 112.7, and 106.5 kJ/mole, respectively. These kinetic data were then used to predict the yield of the various pyrolysis products. It was found that the best prediction was obtained when an integral-mean temperature obtained from the temperature-time curve was used as reaction temperature. The pyrolysis products were analyzed to investigate the influence of the pyrolysis conditions on the composition. The gas consisted mainly of carbon dioxide, carbon monoxide, oxygen, and C/sub 3//sup +/-compounds. The gas composition depended on reaction time as well as reactor temperature. The tar analysis indicated that the tar consisted of about seven compounds. Its major compound was believed to be levoglucosan. Elemental analysis for the char showed that the carbon content increased with increasing temperature.

  19. Chemical degradation kinetics of fibrates: bezafibrate, ciprofibrate and fenofibrate

    Directory of Open Access Journals (Sweden)

    Marcelo Antonio de Oliveira

    Full Text Available ABSTRACT Fibrates are drugs used for the treatment of hypertriglyceridemia and for the prevention of atherosclerosis. Three drugs in the fibrate class, ciprofibrate, fenofibrate and bezafibrate, were chosen for this study because their raw materials are readily available and because scientific publications on these compounds is limited. To evaluate their intrinsic stability, the drugs were exposed to a test condition (temperature, oxidation, UV light exposure, hydrolysis at different pH values and metal ions in solution and then were subjected to analysis by HPLC. The samples were run on a C18 column, with a flow rate of 1.0 mL min-1 in a mobile phase consisting of methanol: 0.01 % phosphoric acid v/v (80:20, with variable detection wavelengths in the UV spectra. The analysis methodology showed satisfactory performance parameters. The three drugs were very unstable, degrading in each of the conditions evaluated. The test conditions of acid and basic hydrolysis showed the most significant degradation. The results demonstrated that the drugs in this class are unstable. Based on these experimentally determined degradation kinetics, it is easy to understand and emphasize the importance of the lack of liquid dosage forms on the market for fibrates because of their instability.

  20. Formation kinetics of furfuryl alcohol in a coffee model system.

    Science.gov (United States)

    Albouchi, Abdullatif; Murkovic, Michael

    2018-03-15

    The production of furfuryl alcohol from green coffee during roasting and the effect of multiple parameters on its formation were studied employing HPLC-DAD. Results show that coffee produces furfuryl alcohol in larger quantities (418µg/g) compared to other beans or seeds (up to 132µg/g) roasted under the same conditions. The kinetics of furfuryl alcohol production resemble those of other process contaminants (e.g., HMF, acrylamide) produced in coffee roasting, with temperature and time of roasting playing significant roles in quantities formed. Different coffee species yielded different amounts of furfuryl alcohol. The data point out that the amounts of furfuryl alcohol found in roasted coffee do not reflect the total amounts produced during roasting because great amounts of furfuryl alcohol (up to 57%) are evaporating and released to the atmosphere during roasting. Finally the effect of the moisture content on furfuryl alcohol formation was found to be of little impact. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Kinetic study of ultrasonic antisolvent crystallization of sirolimus

    Energy Technology Data Exchange (ETDEWEB)

    Gandhi, P.J. [Chemical Engineering Department, S. V. National Institute of Technology, Surat 395007, Gujarat (India); Concept Medical Research Pvt. Ltd., Ground Floor, Narayan Darshan, Nr. Rupam Cinema, Salabatpura, Surat 395003, Gujarat (India); Murthy, Z.V.P.

    2010-03-15

    Sirolimus, generally used in organ transplantation, is derived from bacterium Streptomyces hygroscopicus. Mass transfer controlled ultrasonic antisolvent method was used for determining the precipitation kinetics of sirolimus. The effect of temperature was determined on the particles size, percentage recovery, critical radius of nucleus, mass transfer coefficient, etc. for sirolimus dissolved in methanol and antisolvent water using ultrasonic treatment. The study was done using classical nucleation theory, which can also be applied to precipitation processes. Experiments were carried out at various temperatures; viz: 45, 50, 60 and 70 C and the percentage recoveries of sirolimus were found to be 90.74, 91.5, 92.64 and 93.61%, respectively, for initial amount of 8 mg dissolved in 1 mL of solvent and further introduced into 12 mL of HPLC water. The final average diameters of crystals observed for the temperatures were 1371, 1287, 1063 and 863 nm, respectively. The systems were found to be mass transfer controlling and that the mass diffusivities were found to be about 3.97 x 10{sup -9}, 4.00 x 10{sup -9}, 3.01 x 10{sup -9} and 1.92 x 10{sup -9} m{sup 2}/s, respectively. (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  2. 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%.

  3. Determination of ergosterol levels in barley and malt varieties in the Czech Republic via HPLC.

    Science.gov (United States)

    Jedlicková, Lenka; Gadas, David; Havlová, Pavla; Havel, Josef

    2008-06-11

    Ergosterol is considered to be a suitable indicator of mold infestation in barley and malt. In this study ergosterol levels in different varieties of barley and malt produced in the Czech Republic were determined. A modified high-performance liquid chromatography (HPLC) method was statistically processed, validated (Effivalidation program), and applied to 124 samples of barley and malt. Ergosterol was isolated by extraction and saponification, and the quantification was performed using HPLC with diode array detection. The content of ergosterol ranged between the limit of detection (LOD) and 36.3 mg/kg in barley and between the LOD and 131.1 mg/kg in malt. Ergosterol is presumably connected with metabolites generated when barley grain is attacked by pathogens, and such barley often shows a high overfoaming (gushing) value. However, it was found that the content of ergosterol does not correlate with the degree of beer gushing.

  4. Analysis of the monosaccharide composition of fucoidan by precolumn derivation HPLC

    Science.gov (United States)

    Zhang, Jingjing; Zhang, Quanbin; Wang, Jing; Shi, Xuelian; Zhang, Zhongshan

    2009-09-01

    We developed an HPLC method for analysis of the monosaccharide composition of fucoidans. The fucoidan was hydrolyzed into monosaccharides with 2 mol/L trifluoroacetic acid. Using ribose as the internal standard, the monosaccharide derivatives, obtained with 1-Phenyl-3-methyl-5-pyrazolone (PMP), were separated by reverse-phase HPLC using a gradient elution process, and monitored by ultraviolet detection at 245 nm. In the concentration range of 0.1-2.0 mmol/L, the peak area of each monosaccharide had a good linear relationship with its concentration ( r 2>0.998). The average recoveries of mannose, rhamnose, glucuronic acid, glucose, galactose, xylose, and fucose were 86.2%, 95.1%, 62.5%, 102.0%, 94.8%, 66.6%, and 105.1%, respectively. This method was accurate and had good reproducibility and could be used to determine the monosaccharide contents of fucoidans.

  5. DETERMINATION OF PROTEINS FROM BUFFALO MILK USING HIGH PERFORMANCE LIQUID CROMATOGRAPHY RP-HPLC

    Directory of Open Access Journals (Sweden)

    AURELIA PECE

    2008-10-01

    Full Text Available In the hereby paper, we have undertaken a study on buffalo milk proteins, employing high performance liquid chromatography (HPLC. This RP-HPLC technique is commonly employed in the separation and assessment of caseins K, and in the fresh, as well as processed milk. These methods are also successfully applied in the authenticity and origin assessment of certain cheese products and the qualitative analysis of milk in bubalines, ovines, caprines and bovines (Ferreira si Cacote, 2003; Veloso si colab., 2002. In order to identify the main protein types, we found support in literature data (Miranda si colab., 2004, and thus achieved the chromatographic separation on whole milk, lactoserum and casein samples.

  6. GlycoBase and autoGU: resources for interpreting HPLC-glycan data.

    Science.gov (United States)

    Campbell, Matthew P; Royle, Lousie; Rudd, Pauline M

    2015-01-01

    The biological relevance of protein glycosylation has made glycomics, the comprehensive study to identify all glycans in an organism, indispensable in many research fields. Determining the structure and functional relationship of glycoproteins requires the comprehensive characterization of glycan structures by a range of analytical methods. High performance liquid chromatography (HPLC) is a well-established technology commonly used for the complete structural elucidation of N- and O-linked glycans; however, the analysis of data is a major bottleneck and robust bioinformatic solutions are required. This chapter describes the availability of databases and tools, GlycoBase and autoGU developed in conjunction with the EUROCarbDB initiative, to assist the interpretation of HPLC-glycan data collections.

  7. Determination of diclofenac released from suppositories using UV spectrophotometry, spectra derivative spectrophotometry and HPLC.

    Science.gov (United States)

    Sznitowska, Małgorzata; Stokrocka, Małgorzata

    2007-01-01

    Spectrophotometric method is often recommended in dissolution testing of not only tablets or capsules but also suppositories. Dissolution rate of diclofenac sodium was studied using a pharmacopoeial flow-through apparatus and pH 7.3 buffer. For two lipophilic suppository bases (Witepsol W-32 and H-19) dissolution rate was overestimated with the spectrophotometric zero-order method in comparison to HPLC method, although the difference was statistically significant only in the case of the Witepsol W-32 basis. On the other hand, first derivative spectrophotometry allowed for elimination of the interference of the suppository lipophilic components dissolved in the buffer medium and no difference was observed between the results of this analysis in comparison with HPLC results.

  8. Validation of simultaneous volumetric and HPLC methods for the determination of pridinol mesylate in raw material.

    Science.gov (United States)

    Simionato, Laura D; Ferello, Leonardo; Stamer, Sebastián; Zubata, Patricia D; Segall, Adriana I

    2013-01-01

    Simple, sensitive, and economical simultaneous volumetric and HPLC methods for the determination of pridinol mesylate in raw material have been developed. The volumetric method is based on the reaction of pridinol with sodium lauryl sulphate in diluted sulphuric acid. Dimethyl yellow was used as indicator to detect the end point of the titration in aqueous/organic layer. The HPLC method for the determination of pridinol mesylate employs a reverse phase C18 column at ambient temperature with a mobile phase consisting of acetonitrile: 0.05 M potassium dihydrogen phosphate, pH adjusted to 5.0 (1 : 2, v/v). The flow rate was 0.8 mL/min. Quantitation was achieved with UV detection at 258 nm based on peak area. Both methods were found to be suitable for the quality control of pridinol mesylate in raw material.

  9. Isolation, Identification, and Characterization of One Degradation Product in Ambroxol by HPLC-Hyphenated Techniques

    Science.gov (United States)

    Thummala, Veera Raghava Raju; Ivaturi, Mrutyunjaya Rao; Nittala, Someswara Rao

    2014-01-01

    This study details the isolation, identification, and characterization of ambroxol’s unknown impurity. One unknown impurity of ambroxol was formed in the formulated drug under stress conditions [40°C /75% relative humidity (RH) for 6 months] with the relative retention time (RRT) 0.68 in RP-HPLC. The impurity was enriched by exposing it to heat and it was isolated by using preparative HPLC. The enriched impurity was purified and characterized using the following sophisticated techniques: 2D NMR (gDQ-COSY, gHSQC, and gHMBC), FTIR, and LC-MS/MS. On the basis of the spectral data, the impurity was characterized as trans-4-(6,8-dibromoquinazolin-3(4H)-yl)cyclohexanol. PMID:24959402

  10. HPLC quantification of the HIV-1 protease inhibitor saquinavir in brain and testis of mice.

    Science.gov (United States)

    Mudigonda, Koteshwara; Jukanti, Raju; Apte, Shashank S; Ajjala, Devender R; Shrivastava, Wishu; Kandikere, Vishwottam N; Nirogi, Ramakrishna V S

    2006-10-01

    A rapid, reliable HPLC method with UV detection (240 nm) was developed and validated for quantitation of saquinavir in mice brain and testis. Saquinavir and the internal standard were isolated from homogenized tissue matrices using liquid-liquid extraction procedure and were then analyzed using an isocratic mobile phase by reversed-phase liquid chromatography. The lower limit of quantification was 50 ng/g for both brain and testis. A linear dynamic range of 50-5000 ng/g for both brain and testis was established. This HPLC method was validated with between-batch precision of 0.5-4.4 and 1.5-5.5% for brain and testis, respectively. The between-batch accuracy was 94.7-105.9% and 97.5-105.0% for brain and testis, respectively. The present method was applied for tissue distribution studies of the novel drug delivery systems of saquinavir in mice.

  11. Targeted natural product isolation guided by HPLC-SPE-NMR: Constituents of Hubertia species

    DEFF Research Database (Denmark)

    Sprogoe, K.; Staek, D.; Jager, A.K.

    2007-01-01

    -hydroxyphenyl)acetyl]quinic acid (3), was performed. Finally, targeted isolation of 1 was achieved by SPE fractionation and preparative HPLC, followed by evaluation of its antioxidant and antimicrobial activity. In contrast to chlorogenic acid and 3,5-di-O-caffeoylquinic acid, which act as antioxidants......The hyphenated technique, high-performance liquid chromatography-solid-phase extraction-nuclear magnetic resonance spectroscopy (HPLC-SPE-NMR), has been applied for rapid identification of novel natural products in crude extracts of Hubertia ambavilla and Hubertia tomentosa. The technique allowed...... full or partial identification of all major extract constituents and demonstrated the presence of unusual quinic acid derivatives containing the (1-hydroxy-4-oxocyclohexa-2,5-dienyl)acetyl residue that exhibit strongly coupled ABXY patterns, the parameters of which were obtained by spin simulations...

  12. HPLC-DPPH Screening Method for Evaluation of Antioxidant Compounds Extracted from Semen Oroxyli

    Directory of Open Access Journals (Sweden)

    Renyi Yan

    2014-04-01

    Full Text Available Semen Oroxyli, derived from the seed of Oroxylum indicum L., is a commonly used Traditional Chinese Medicine with beneficial effects against several respiratory disorders. Antioxidative flavonoids may be partly responsible for its medicinal functions. The aim of this study was to rapidly determine the antioxidants in Semen Oroxyli based on a HPLC-DPPH method. Four major flavonoids, baicalein-7-O-gentiobioside, baicalein-7-O-glucoside, baicalein, and baicalin, were identified as the active components against DPPH free radicals, which is in accord with the results of our former traditional activity-guided phytochemical study. The oxidative products of the four antioxidant flavonoids were studied in the DPPH spiking HPLC assay, it was suggested that the three active flavonoid glycosides were converted into 5,6-dihydroxy-7-methoxyflavone, which implied that an additional hydroxyl at C-6 in 5,7-dihydroxyflavones plays an important role in the DPPH assay.

  13. Isolation and characterization of novel degradation products of Doxofylline using HPLC, FTIR, LCMS and NMR.

    Science.gov (United States)

    Raju, Ch Krishnam; Pandey, Avadhesh K; S, Gururaj; Ghosh, Kaushik; Pola, Arunima; Goud P, Sanath Kumar; Jaywant, Mrunal A; Navalgund, Sameer G

    2017-06-05

    Forced degradation of Doxofylline (DFL) in different stress (base and peroxide) conditions gave rise to two potential unknown impurities. These unknown degradation products DFL DEG-I and DFL DEG-II were evaluated using a new-reverse-phase high performance liquid chromatography (HPLC), where it was eluted at 0.44 and 1.09 relative retention times to DFL peak. DFL DEG-I and DFL DEG-II were isolated using preparative HPLC from degradation mixtures. The structure of DFL DEG-I and DFL DEG-II were elucidated using high resolution MS, multi-dimensional NMR and FTIR spectroscopic techniques, and characterized. The stereochemistry of the enantiomers in DFL DEG-II has further been investigated using computational techniques. To the best of our knowledge, DFL DEG-I and DFL DEG-II are novel impurities and not reported elsewhere. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Separation of Alkyne Enantiomers by Chiral Column HPLC Analysis of Their Cobalt-Complexes

    Directory of Open Access Journals (Sweden)

    Qiaoyun Liu

    2017-03-01

    Full Text Available Separation of the enantiomers of new chiral alkynes in strategic syntheses and bioorthogonal studies is always problematic. The chiral column high-performance liquid chromatography (HPLC method in general could not be directly used to resolve such substrates, since the differentiation of the alkyne segment with the other alkane/alkene segment is not significant in the stationary phase, and the alkyne group is not a good UV chromophore. Usually, a pre-column derivatization reaction with a tedious workup procedure is needed. Making use of easily-prepared stable alkyne-cobalt-complexes, we developed a simple and general method by analyzing the in situ generated cobalt-complex of chiral alkynes using chiral column HPLC. This new method is especially suitable for the alkynes without chromophores and other derivable groups.

  15. HPLC determination of certain flavonoids and terpene lactones in selected Ginkgo biloba L. phytopharmaceuticals.

    Science.gov (United States)

    Mesbah, Mostafa K; Khalifa, Sherief I; El-Gindy, Alaa; Tawfik, Kamilia A

    2005-01-01

    The biologically active secondary metabolites of Ginkgo biloba extract EGb 761 in phytopharmaceuticals were analyzed using two simple, rapid, accurate and sensitive HPLC methods. The proposed methods were successfully applied in the determination of terpenes and flavonoids in four phytopharmaceutical preparations selected from the Egyptian market. The terpenes; ginkgolide A, ginkgolide B, and bilobalide were analyzed using RP 18 column with a mobile phase consisting of water/methanol/isopropanol (72.5:17.5:10, v/v) at a flow rate of 1 ml min-1 and UV detection at 220 nm. The flavonoids; quercetin and kaempferol were analyzed using RP 18 column in a step gradient elution with acetonitrile and water at pH 3.3 and flow rate of 1.5 ml min-1 with UV detection at 370 nm. The two HPLC methods were completely validated.

  16. New determination method for sulfonation degree of phthalic anhydride by RP-HPLC.

    Science.gov (United States)

    Zhu, Lijun; Song, Lechun; Liu, Bin; Zhou, Yulu; Xiang, Yuzhi; Xia, Daohong

    2014-01-01

    A novel method was developed to monitor the reaction process and evaluate the sulfonation level in the sulfonation of phthalic anhydride by reversed-phase high-performance liquid chromatography (RP-HPLC). The product peak was identified in chromatograms through product analysis and by comparing its retention time with that of standard compounds. By comparing the hydrolysis and alcoholysis methods, optimized pretreatment of the sample was found for RP-HPLC. Based on the determined percentages of phthalic anhydride and sulfonated phthalic anhydride in the mixture, the degree of sulfonation was calculated. When the sulfonation degree of phthalic anhydride was in the range of 2.8-71%, the recovery of 97-104% was achieved, and the procedure was rapid and accurate.

  17. Chemical fingerprint and quantitative analysis for quality control of polyphenols extracted from pomegranate peel by HPLC.

    Science.gov (United States)

    Li, Jianke; He, Xiaoye; Li, Mengying; Zhao, Wei; Liu, Liu; Kong, Xianghong

    2015-06-01

    A simple and efficient HPLC fingerprint method was developed and validated for quality control of the polyphenols extracted from pomegranate peel (PPPs). Ten batches of pomegranate collected from different orchards in Shaanxi Lintong of China were used to establish the fingerprint. For the fingerprint analysis, 15 characteristic peaks were selected to evaluate the similarities of 10 batches of the PPPs. The similarities of the PPPs samples were all more than 0.968, indicating that the samples from different areas of Lintong were consistent. Additionally, simultaneous quantification of eight monophenols (including gallic acid, punicalagin, catechin, chlorogenic acid, caffeic acid, epicatechin, rutin, and ellagic acid) in the PPPs was conducted to interpret the consistency of the quality test. The results demonstrated that the HPLC fingerprint as a characteristic distinguishing method combining similarity evaluation and quantitative analysis can be successfully used to assess the quality and to identify the authenticity of the PPPs. Copyright © 2014 Elsevier Ltd. All rights reserved.

  18. [Comparison between colorimetry and HPLC on the stability test of roxithromycin].

    Science.gov (United States)

    Wei, Z P; Mao, S R; Bi, D Z

    2000-11-01

    To compare the stability of roxithromycin in solutions of different pH. Roxithromycin solutions of different pH were prepared with water, simulate intestinal fluid (SIF) and simulate gastric fluid (SGF) shown to be the stability of these solutions were tested by colorimetry and HPLC. Roxithromycin was stable in water, SGF and SIF determined by colorimetry. However, it was found to be stable only in water and SIF but unstable in SGF as determined by HPLC. Roxithromycin is unstable in acidic medium like SGF. The metabolite of roxithromycin showed unfavorable interference on the assay of roxithromycin when colorimetry was used. Colorimetry can not be used for the determination and assay of roxithromycin in acidic solution like SGF.

  19. Some Aspects of Extended Kinetic Equation

    Directory of Open Access Journals (Sweden)

    Dilip Kumar

    2015-09-01

    Full Text Available Motivated by the pathway model of Mathai introduced in 2005 [Linear Algebra and Its Applications, 396, 317–328] we extend the standard kinetic equations. Connection of the extended kinetic equation with fractional calculus operator is established. The solution of the general form of the fractional kinetic equation is obtained through Laplace transform. The results for the standard kinetic equation are obtained as the limiting case.

  20. Holographic kinetic k-essence model

    Energy Technology Data Exchange (ETDEWEB)

    Cruz, Norman [Departamento de Fisica, Facultad de Ciencia, Universidad de Santiago de Chile, Casilla 307, Santiago (Chile)], E-mail: ncruz@lauca.usach.cl; Gonzalez-Diaz, Pedro F.; Rozas-Fernandez, Alberto [Colina de los Chopos, Instituto de Fisica Fundamental, Consejo Superior de Investigaciones Cientificas, Serrano 121, 28006 Madrid (Spain)], E-mail: a.rozas@cfmac.csic.es; Sanchez, Guillermo [Departamento de Matematica y Ciencia de la Computacion, Facultad de Ciencia, Universidad de Santiago de Chile, Casilla 307, Santiago (Chile)], E-mail: gsanchez@usach.cl

    2009-08-31

    We consider a connection between the holographic dark energy density and the kinetic k-essence energy density in a flat FRW universe. With the choice c{>=}1, the holographic dark energy can be described by a kinetic k-essence scalar field in a certain way. In this Letter we show this kinetic k-essential description of the holographic dark energy with c{>=}1 and reconstruct the kinetic k-essence function F(X)

  1. Modeling the kinetics of vulcanization polydienes

    OpenAIRE

    V. I. Molchanov; O. V. Karmanova; S. G. Tikhomirov

    2013-01-01

    A model of vulcanization kinetics, which allows describing the kinetic curves of any form and on the basis of economical laboratory experiment analytically evaluate the kinetics of isothermal curing was proposed. In studying the kinetics of vulcanization, we assumed that the individual stages of the vulcanization process differ significantly speed and to determine the parameters on reometric curve isolated several areas. It allows to describe the process of a set of simple coupled first and s...

  2. Modeling the kinetics of vulcanization polydienes

    Directory of Open Access Journals (Sweden)

    V. I. Molchanov

    2013-01-01

    Full Text Available A model of vulcanization kinetics, which allows describing the kinetic curves of any form and on the basis of economical laboratory experiment analytically evaluate the kinetics of isothermal curing was proposed. In studying the kinetics of vulcanization, we assumed that the individual stages of the vulcanization process differ significantly speed and to determine the parameters on reometric curve isolated several areas. It allows to describe the process of a set of simple coupled first and second order vulcanization reactions.

  3. Transient state kinetics tutorial using the kinetics simulation program, KINSIM.

    OpenAIRE

    Wachsstock, D.H.; Pollard, T. D.

    1994-01-01

    This article provides an introduction to a computer tutorial on transient state kinetics. The tutorial uses our Macintosh version of the computer program, KINSIM, that calculates the time course of reactions. KINSIM is also available for other popular computers. This program allows even those investigators not mathematically inclined to evaluate the rate constants for the transitions between the intermediates in any reaction mechanism. These rate constants are one of the insights that are ess...

  4. Validated HPLC-PDA method for rosmarinic acid quantification in Rosemary

    OpenAIRE

    Bara, María Teresa. F.; Rezende, Kênnia R.; Alves,Suzana F.; Oliveira, Ezequiane M. S.; Chaul, Luiza T.; Conceição, Edmilson C. da; Couto, Renê O.; Paula, José R.

    2011-01-01

    A fast and simple HPLC-PDA method for rosmarinic acid quantification in Rosemary leaves powder was validated. The analyses were performed using a C18 column in isocratic conditions and detection at 254 nm. Performing the system suitability tests, the method showed to be capable of providing data of acceptable quality. Results showed that the method was selective, linear for concentration ranges between 2.5-50 μg.mL–1 , sensitive, precise, accurate and robust. The main advantages of...

  5. Potential diagnostic of Branched-Chain Ketoaciduria by HPLC-DAD

    OpenAIRE

    Trintinalia, Maíra Magalhães; Alves, Atecla Nunciata Lopes; Fernandes, Liliam; Bechara, Etelvino Jose Henriques; Assunção, Nilson Antonio

    2014-01-01

    A system of high performance liquid chromatography (HPLC) was used for the development and validation of efficient method for quantitative determination of three aminoacids involved in the inherited metabolic disease Branched-Chain Ketoaciduria (BCK), also called maple syrup urine disease. The analytical conditions were selected in order to obtain baseline separation profiles of the amino acids known to be altered in blood plasma of BCK patients, namely L-valine, L-isoleucine, and L-leucine. ...

  6. PRELIMINARY PHYTOCHEMICAL SCREENING AND HPLC ANALYSIS OF FLAVONOID FROM METHANOLIC EXTRACT OF LEAVES OF ANNONA SQUAMOSA

    OpenAIRE

    Soni Himesh; Sharma Sarvesh; Patel Sita Sharan; Mishra K; Singhai A.K.

    2011-01-01

    The present paper deals with the phytochemical screening of therapeutic importance from Annona squamosa leaves, an important medicinal plant. This study involves the preliminary screening, qualitative thin layer chromatographic separation of secondary metabolites from leaves of A. squamosa. Further, HPLC Flavonoids profile of the methanolic extract had been studied. The generated data has provided the basis for its wide uses as the therapeutant in the traditional and folk medicines.

  7. Comparison of UHPLC and HPLC in Benzodiazepines Analysis of Postmortem Samples

    Science.gov (United States)

    Behnoush, Behnam; Sheikhazadi, Ardeshir; Bazmi, Elham; Fattahi, Akbar; Sheikhazadi, Elham; Saberi Anary, Seyed Hossein

    2015-01-01

    Abstract The aim of this study was to compare system efficiency and analysis duration regarding the solvent consumption and system maintenance in high-pressure liquid chromatography (HPLC) and ultra high-pressure liquid chromatography (UHPLC). In a case–control study, standard solutions of 7 benzodiazepines (BZs) and 73 biological samples such as urine, tissue, stomach content, and bile that screened positive for BZs were analyzed by HPLC and UHPLC in laboratory of forensic toxicology during 2012 to 2013. HPLC analysis was performed using a Knauer by 100-5 C-18 column (250 mm × 4.6 mm) and Knauer photodiode array detector (PAD). UHPLC analysis was performed using Knauer PAD detector with cooling autosampler and Eurospher II 100-3 C-18 column (100 mm × 3 mm) and also 2 pumps. The mean retention time, standard deviation, flow rate, and repeatability of analytical results were compared by using 2 methods. Routine runtimes in HPLC and UHPLC took 40 and 15 minutes, respectively. Changes in mobile phase composition of the 2 methods were not required. Flow rate and solvent consumption in UHPLC decreased. Diazepam and flurazepam were detected more frequently in biological samples. In UHPLC, small particle size and short length of column cause effective separation of BZs in a very short time. Reduced flow rate, solvent consumption, and injection volume cause more efficiency and less analysis costs. Thus, in the detection of BZs, UHPLC is an accurate, sensitive, and fast method with less cost of analysis. PMID:25860209

  8. Assessment of radiochemical purity of [{sup 18}F]fludeoxyglucose by high pressure liquid chromatography (HPLC)

    Energy Technology Data Exchange (ETDEWEB)

    Lacerda, Aline E.; Silva, Juliana B.; Silveira, Marina B.; Ferreira, Soraya Z., E-mail: radiofarmacoscdtn@cdtn.b [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil). Unidade de Pesquisa e Producao de Radiofarmacos

    2011-07-01

    The quality control of [{sup 18}F]fludeoxyglucose ({sup 18}FDG) has received attention due to its increasing clinical use. Although the quality requirements of {sup 18}FDG are established in various pharmacopoeia, the suitability of all testing methods used should be verified under actual conditions of use and documented. The aim of this study was to develop a high pressure liquid chromatography (HPLC) method for radiochemical purity evaluation of {sup 18}FDG, based on pharmacopoeia references, and to verify its suitability for routine quality control in our centre. HPLC analysis was performed with an Agilent HPLC. {sup 18}FDG and impurities were separated on an anion-exchange column by isocratic elution with 0.1 M NaOH as the mobile phase. Detection was accomplished with refractive index and NaI (Tl) scintillation detectors. The flow rate of the mobile phase was set at 0.8 mL/min and the column temperature was kept at 35 deg C. Specificity, linearity, precision and robustness were assessed to verify if the method was adequate for its intended purpose. Retention time of {sup 18}FDG was not affected by the presence of other components of the formulation and a good peak resolution was achieved. The analytical curve of {sup 18}FDG was linear, with a correlation coefficient value of 0.9995. Intraday repeatable precision, reported as the relative standard deviation, was 0.11%. Analytical procedure remained unaffected by small variations in mobile phase flow rate. Results evidenced that HPLC is suitable for radiochemical purity evaluation of {sup 18}FDG, considering operational conditions of our laboratory. (author)

  9. HPLC fucoxanthin profiles of a microalga, a macroalga and a pure fucoxanthin standard.

    Science.gov (United States)

    Foo, Su Chern; Yusoff, Fatimah Md; Ismail, Maznah; Basri, Mahiran; Yau, Sook Kun; Khong, Nicholas M H; Chan, Kim Wei; Ebrahimi, Mahdi

    2017-02-01

    Data in this article illustrate representative fucoxanthin chromatograms of a microalga, Chaetoceros calcitrans; a macroalga, Saccharina japonica and; a pure fucoxanthin standard. High performance liquid chromatography (HPLC) eluted fucoxanthin at the 7.008±0.024th min. This data article refers to the research article ''Antioxidant capacities of fucoxanthin-producing algae as influenced by their carotenoid and phenolic contents'' Foo et al. [1]; where a more comprehensive data interpretation and analysis is explained.

  10. Reversed-phase HPLC retention data in correlation studies with in lipophilicity molecular descriptors of carotenoids

    OpenAIRE

    Podunavac-Kuzmanović Sanja O.; Jevrić Lidija R.; Tepić Aleksandra N.; Šumić Zdravko

    2013-01-01

    Influence of chemical structure on the lipophilicity of isolated free carotenoids from paprika oleoresin has been studied by QSRR approach (Quantitative structure-retention relationship). The chromatographic behavior of these compounds was investigated by using reversed phase high-pressure liquid chromatography (RP HPLC). Retention mechanism has been determined using the following mobile phase: acetone -water, on reversed - phase column (SB-C18). A variety ...

  11. Antiproliferative activity of Citrus juices and HPLC evaluation of their flavonoid composition.

    Science.gov (United States)

    Camarda, Lorenzo; Di Stefano, Vita; Del Bosco, Sergio Fatta; Schillaci, Domenico

    2007-09-01

    The antiproliferative activity of fresh fruit juices extracted from Citrus sinensis (cv. Washington Navel and cv. Sanguinello), C. deliciosa cv. Avana, C. clementina cv. Nules, C. aurantium subsp. myrtifolia , was evaluated against K562 (human chronic myelogenous leukemia), HL-60 (human leukemia) and MCF-7 (human breast adenocarcinoma) cell lines. All the juices tested showed antiproliferative activity. Moreover, the pattern of the main flavanone compounds in the juices has been determined by HPLC analysis.

  12. Kinetic modelling of enzymatic starch hydrolysis

    NARCIS (Netherlands)

    Bednarska, K.A.

    2015-01-01

    Kinetic modelling of enzymatic starch hydrolysis – a summary K.A. Bednarska The dissertation entitled ‘Kinetic modelling of enzymatic starch hydrolysis’ describes the enzymatic hydrolysis and kinetic modelling of liquefaction and saccharification of wheat starch.

  13. Kinetical foundations of non-conventional statistics

    Science.gov (United States)

    Kaniadakis, G.; Quarati, P.; Scarfone, A. M.

    2002-03-01

    After considering the kinetical interaction principle (KIP) introduced by Kaniadakis (Physica A 296 (2001) 405), we study in the Boltzmann picture, the evolution equation and the H-theorem for non-extensive systems. The q-kinetics and the κ-kinetics are studied in detail starting from the most general non-linear Boltzmann equation compatible with the KIP.

  14. Kinetical Foundations of Non Conventional Statistics

    OpenAIRE

    Kaniadakis, G.; Quarati, P.; Scarfone, A. M.

    2001-01-01

    After considering the kinetical interaction principle (KIP) introduced in ref. Physica A {\\bf296}, 405 (2001), we study in the Boltzmann picture, the evolution equation and the H-theorem for non extensive systems. The $q$-kinetics and the $\\kappa$-kinetics are studied in detail starting from the most general non linear Boltzmann equation compatible with the KIP.

  15. Erbium hydride thermal desorption : controlling kinetics.

    Energy Technology Data Exchange (ETDEWEB)

    Ferrizz, Robert Matthew

    2007-08-01

    Thermal desorption spectroscopy (TDS) is used to study the decomposition kinetics of erbium hydride thin films. The TDS results presented in this report show that hydride film processing parameters directly impact thermal stability. Issues to be addressed include desorption kinetics for dihydrides and trihydrides, and the effect of film growth parameters, loading parameters, and substrate selection on desorption kinetics.

  16. Kinetics of yttrium oxide carbochlorination

    Energy Technology Data Exchange (ETDEWEB)

    Gaviria, J.P., E-mail: gaviriaj@cab.cnea.gov.ar [Division Cinetica Quimica - Complejo Tecnologico Pilcaniyeu - Centro Atomico Bariloche - Comision Nacional de Energia Atomica, Av. Bustillo km 9500 (8400), S.C. de Bariloche, Rio Negro (Argentina); Consejo Nacional de Investigaciones Cientificas y Tecnicas (Argentina); Fouga, G.G. [Division Cinetica Quimica - Complejo Tecnologico Pilcaniyeu - Centro Atomico Bariloche - Comision Nacional de Energia Atomica, Av. Bustillo km 9500 (8400), S.C. de Bariloche, Rio Negro (Argentina); Consejo Nacional de Investigaciones Cientificas y Tecnicas (Argentina); Bohe, A.E. [Division Cinetica Quimica - Complejo Tecnologico Pilcaniyeu - Centro Atomico Bariloche - Comision Nacional de Energia Atomica, Av. Bustillo km 9500 (8400), S.C. de Bariloche, Rio Negro (Argentina); Consejo Nacional de Investigaciones Cientificas y Tecnicas (Argentina); Centro Regional Universitario Bariloche - Universidad Nacional del Comahue (Argentina)

    2011-04-20

    Research highlights: {yields} Chlorination kinetics of Y{sub 2}O{sub 3}-C system was studied by thermogravimetry. {yields} The influence of carbon content, flow rate, sample mass and pCl{sub 2} were evaluated. {yields} Reaction proceeds through three successive stages until the formation of YCl{sub 3}(l). {yields}STAGE I is the formation of YOCl(s) and is under chemical control for T < 700 {sup o}C. {yields}STAGE I follows a nucleation and growth model. Kinetics parameters were obtained. - Abstract: The chlorination kinetics of the Y{sub 2}O{sub 3}-sucrose carbon system was studied by thermogravimetry. This work is a continuation of a previous one in which the reaction stages and the stoichiometry of each reaction have been determined. The influence of carbon content, total flow rate, sample initial mass and chlorine partial pressure was evaluated. The effect of carbon content on the reactive mixture was studied between 6.7 and 70% (carbon mass/total mass). The results showed that the reaction rate of each stage is strongly increased as the carbon content increases and the range of occurrence of the stages depends on the amount of carbon in the solid reactive mixture. The formation reaction of YOCl (STAGE I) is chemically controlled for temperatures lower than 700 {sup o}C with average effective activation energies of 165 {+-} 6 and 152 {+-} 7 kJ/mol for 8.7 and 16.7%C, respectively. The formation of the YOCl follows a nucleation and growth mechanism, with a combination of continuous nucleation and site saturation, and anisotropic growth controlled by diffusion. The kinetics of STAGE I can be expressed by the following global rate equation that includes the variables analyzed: (d{alpha})/(dt) =k{sub 0}Bexp(-(Ea)/(R{sub g}T) )pCl{sub 2}{l_brace}n(1-{alpha})[-ln(1-{alpha})]{r_brace}{sup (n-1)/n} where k{sub 0}B = 1.9 x 10{sup 4}, n = 1.20 for 8.7%C, and k{sub 0}B = 8.4 x 10{sup 3}, n = 1.14 for 16.7%C. STAGES II and III correspond to the YOCl carbochlorination to

  17. Determination of impurities and degradation products from veterinary medicinal products by HPLC method

    Directory of Open Access Journals (Sweden)

    Elena Gabriela Oltean

    2014-06-01

    Full Text Available The organic or inorganic impurities in the veterinary medicinal product can derive from starting materials, manufacturing process, incomplete purification, inappropriate storage. The acceptable levels of impurities in pharmaceuticals are estimated by comparison with standard solutions, according to the appropriate monographs. Forced degradation studies determine the stability of the method of dosage for the active compounds and for the entire finished product under excessive accelerated degradation conditions. They also provide information on degradation pathways and selectivity of analytical methods applied. The information provided by the degradation studies on the active compound and finished pharmaceutical product should demonstrate the specificity of the analytical method regarding impurities. Forced degradation studies should demonstrate that the impurities and degradation products generated do not interfere with the active compound. The current forced degradation methods consist of acid hydrolysis, basic hydrolysis, oxidation, exposure of the medicinal product to temperature and light. HPLC methods are an integral analytical instrument for the analysis of the medicinal product. The HPLC method should be able to separate, detect and quantify various specific degradation products that can appear after manufacture or storage of the medicinal product, as well as new elements appearing after synthesis. FDA and ICH guidelines recommend the enclosure of the results, including the chromatograms specific to the forced degradation-subjected medicinal product, in the documentation for marketing authorization. Using HPLC methods in forced degradation studies on medicinal products provides relevant information on the method of determination for the formulation of the medicinal product, synthesis product, packaging methods and storage.

  18. Reliable HPLC separation, vibrational circular dichroism spectra, and absolute configurations of isoborneol enantiomers.

    Science.gov (United States)

    Gao, Rui-Qi; Fan, Jun; Tan, Qi; Guo, Dong; Chen, Tao; He, Ru-Jian; Li, Dan; Zhang, Hui; Zhang, Wei-Guang

    2017-09-01

    Resolution of chiral compounds has played an important role in the pharmaceutical field, involving detailed studies of pharmacokinetics, physiological, toxicological, and metabolic activities of enantiomers. Herein, a reliable method by high-performance liquid chromatography (HPLC) coupled with an optical rotation detector was developed to separate isoborneol enantiomers. A cellulose tris(3, 5-dimethylphenylcarbamate)-coated chiral stationary phase showed the best separation performance for isoborneol enantiomers in the normal phase among four polysaccharide chiral packings. The effects of alcoholic modifiers and column temperature were studied in detail. Resolution of the isoborneol racemate displayed a downward trend along with an increase in the content of ethanol and column temperature, indicating that less ethanol in the mobile phase and lower temperature were favorable to this process. Moreover, two isoborneol enantiomers were obtained via a semipreparative chiral HPLC technique under optimum conditions, and further characterized by analytical HPLC, and experimental and calculated vibrational circular dichroism (VCD) spectroscopy, respectively. The solution VCD spectrum of the first-eluted component was consistent with the Density Functional Theory (DFT) calculated pattern based on the SSS configuration, indicating that this enantiomer should be (1S, 2S, 4S)-(+)-isoborneol. Briefly, these results have provided reliable information to establish a method for analysis, preparative separation, and absolute configuration of chiral compounds without typical chromophoric groups. © 2017 Wiley Periodicals, Inc.

  19. Identification and Quantitation of Asparagine and Citrulline Using High-Performance Liquid Chromatography (HPLC

    Directory of Open Access Journals (Sweden)

    Cheng Bai

    2007-01-01

    Full Text Available High-performance liquid chromatography (HPLC analysis was used for identification of two problematic ureides, asparagine and citrulline. We report here a technique that takes advantage of the predictable delay in retention time of the co-asparagine/citrulline peak to enable both qualitative and quantitative analysis of asparagine and citrulline using the Platinum EPS reverse-phase C18 column (Alltech Associates. Asparagine alone is eluted earlier than citrulline alone, but when both of them are present in biological samples they may co-elute. HPLC retention times for asparagine and citrulline were influenced by other ureides in the mixture. We found that at various asparagines and citrulline ratios [= 3:1, 1:1, and 1:3; corresponding to 75:25, 50:50, and 25:75 (μMol ml–1/μMol ml–1], the resulting peak exhibited different retention times. Adjustment of ureide ratios as internal standards enables peak identification and quantification. Both chemicals were quantified in xylem sap samples of pecan [Carya illinoinensis (Wangenh. K. Koch] trees. Analysis revealed that tree nickel nutrition status affects relative concentrations of Urea Cycle intermediates, asparagine and citrulline, present in sap. Consequently, we concluded that the HPLC methods are presented to enable qualitative and quantitative analysis of these metabolically important ureides.

  20. Application of RP-HPLC in Detecting Content of Ferulic Acid in Fuke Qianjin Capsule

    Directory of Open Access Journals (Sweden)

    Ming-zhi WANG

    2015-09-01

    Full Text Available Objective: To establish a method for the determination of ferulic acid content in Fuke Qianjin Capsule. Methods: Reversed phase high performance liquid chromatography (RP-HPLC was applied in this study, with the detection conditions as follows: chromatographic column: Boston green ODS·min-1, detection wavelength: 316 nm, and column temperature: 30℃. C18 (250 mm × 4.6 mm, 5 μm, mobile phase: methanol-0.1% phosphoric acid (25:75, flow velocity: 1.0 mLResults: Ferulic acid, whose sample size was 0.017760-0.10656 μg, was in favorable linear relationship with the integral value of peak area, with correlation coefficient r=0.9998. The average sample-injecting recovery rate and degree of precision (RSD were 97.6% (n=6 and 1.6%, respectively. The results of this study also showed that the specificity of RP-HPLC in this study was excellent; negative samples had no interference on chromatographic peak of target substance (ferulic acid; and RSD of accuracy, repeatability, stability and recovery rate were 1.1%, 1.4%, 1.2% and 1.6%, respectively.Conclusion: RP-HPLC is accurate, rapid, stable and convenient, so it can be used as an optimal method for the detection of ferulic acid content in Fuke Qianjin Capsule.

  1. Analytical standards production for the analysis of pomegranate anthocyanins by HPLC

    Directory of Open Access Journals (Sweden)

    Manuela Cristina Pessanha de Araújo Santiago

    2014-03-01

    Full Text Available Pomegranate (Punica granatum L. is a fruit with a long medicinal history, especially due to its phenolic compounds content, such as the anthocyanins, which are reported as one of the most important natural antioxidants. The analysis of the anthocyanins by high performance liquid chromatography (HPLC can be considered as an important tool to evaluate the quality of pomegranate juice. For research laboratories the major challenge in using HPLC for quantitative analyses is the acquisition of high purity analytical standards, since these are expensive and in some cases not even commercially available. The aim of this study was to obtain analytical standards for the qualitative and quantitative analysis of the anthocyanins from pomegranate. Five vegetable matrices (pomegranate flower, jambolan, jabuticaba, blackberry and strawberry fruits were used to isolate each of the six anthocyanins present in pomegranate fruit, using an analytical HPLC scale with non-destructive detection, it being possible to subsequently use them as analytical standards. Furthermore, their identities were confirmed by high resolution mass spectrometry. The proposed procedure showed that it is possible to obtain analytical standards of anthocyanins with a high purity grade (98.0 to 99.9% from natural sources, which was proved to be an economic strategy for the production of standards by laboratories according to their research requirements.

  2. Metabolite profiling of leek (Allium porrum L) cultivars by (1) H NMR and HPLC-MS.

    Science.gov (United States)

    Soininen, Tuula H; Jukarainen, Niko; Soininen, Pasi; Auriola, Seppo O K; Julkunen-Tiitto, Riitta; Oleszek, Wieslaw; Stochmal, Anna; Karjalainen, Reijo O; Vepsäläinen, Jouko J

    2014-01-01

    Leek (Allium ampeloprasum var. porrum) is consumed as a vegetable throughout the world. However, little is known about the metabolites of leek cultivars, especially those with potentially important beneficial properties for human health. We provide new information for the overall metabolite composition of several leek cultivars grown in Europe by using HPLC-MS and (1) H NMR. The use of a novel CTLS/NMR (constrained total-line-shape nuclear magnetic resonance) approach was found to be capable of reliable quantification, even with overlapping metabolite signals in the (1) H NMR of plant metabolites. Additionally, a new application for leek flavonoids was optimised for HPLC-MS. The total concentration of carbohydrates (glucose, fructose, kestose/nystose and sucrose) and nine amino acids varied by fourfold in leek juice from different cultivars, while the total concentrations of four organic acids were similar in all cultivars. All the quantified flavonols were kaempferol derivatives or quercetin derivatives and threefold differences in flavonol concentrations were detected between cultivars. In this study, various phytochemical profiles were determined for several leek cultivars by (1) H NMR spectroscopy with CTLS combined with HPLC-MS. The wide variation in bioactive compounds among commercial leek cultivars offers promising opportunities for breeders to raise the levels of important biochemical compounds in leek breeding lines, and also provides some objective measure for quality assurance for the leek industry. Copyright © 2014 John Wiley & Sons, Ltd.

  3. Sources of errors in the quantitative analysis of food carotenoids by HPLC.

    Science.gov (United States)

    Kimura, M; Rodriguez-Amaya, D B

    1999-09-01

    Several factors render carotenoid determination inherently difficult. Thus, in spite of advances in analytical instrumentation, discrepancies in quantitative results on carotenoids can be encountered in the international literature. A good part of the errors comes from the pre-chromatographic steps such as: sampling scheme that does not yield samples representative of the food lots under investigation; sample preparation which does not maintain representativity and guarantee homogeneity of the analytical sample; incomplete extraction; physical losses of carotenoids during the various steps, especially during partition or washing and by adsorption to glass walls of containers; isomerization and oxidation of carotenoids during analysis. On the other hand, although currently considered the method of choice for carotenoids, high performance liquid chromatography (HPLC) is subject to various sources of errors, such as: incompatibility of the injection solvent and the mobile phase, resulting in distorted or split peaks; erroneous identification; unavailability, impurity and instability of carotenoid standards; quantification of highly overlapping peaks; low recovery from the HPLC column; errors in the preparation of standard solutions and in the calibration procedure; calculation errors. Illustrations of the possible errors in the quantification of carotenoids by HPLC are presented.

  4. Quantitative analysis of eugenol in clove extract by a validated HPLC method.

    Science.gov (United States)

    Yun, So-Mi; Lee, Myoung-Heon; Lee, Kwang-Jick; Ku, Hyun-Ok; Son, Seong-Wan; Joo, Yi-Seok

    2010-01-01

    Clove (Eugenia caryophyllata) is a well-known medicinal plant used for diarrhea, digestive disorders, or in antiseptics in Korea. Eugenol is the main active ingredient of clove and has been chosen as a marker compound for the chemical evaluation or QC of clove. This paper reports the development and validation of an HPLC-diode array detection (DAD) method for the determination of eugenol in clove. HPLC separation was accomplished on an XTerra RP18 column (250 x 4.6 mm id, 5 microm) with an isocratic mobile phase of 60% methanol and DAD at 280 nm. Calibration graphs were linear with very good correlation coefficients (r2 > 0.9999) from 12.5 to 1000 ng/mL. The LOD was 0.81 and the LOQ was 2.47 ng/mL. The method showed good intraday precision (%RSD 0.08-0.27%) and interday precision (%RSD 0.32-1.19%). The method was applied to the analysis of eugenol from clove cultivated in various countries (Indonesia, Singapore, and China). Quantitative analysis of the 15 clove samples showed that the content of eugenol varied significantly, ranging from 163 to 1049 ppb. The method of determination of eugenol by HPLC is accurate to evaluate the quality and safety assurance of clove, based on the results of this study.

  5. Stability-indicating HPLC method for the determination of darunavir ethanolate.

    Science.gov (United States)

    Reddy, B V Rami; Jyothi, G; Reddy, B S; Raman, N V V S S; Reddy, K Subhash Chander; Rambabu, C

    2013-01-01

    A novel stability-indicating reversed-phase high-performance liquid chromatographic (HPLC) method has been developed for the quantitative determination of darunavir ethanolate, an HIV-1 protease inhibitor. The chromatographic separation was achieved using an X-Bridge C18 (150 × 4.6 mm × 3.5 µm) HPLC column in isocratic mode employing 0.01M ammonium formate (pH.3.0) buffer and acetonitrile in the ratio of 55:45 (v/v) with a flow rate of 1.0 mL/min. The detector wavelength was monitored at 265 nm and the column temperature was maintained at 30°C. Darunavir ethanolate was exposed to thermal, photolytic, acid, base and oxidative stress conditions. Considerable degradation of the drug substance was found to occur under acid, base and oxidative stress conditions. The peak homogeneity data of darunavir ethanolate obtained by photodiode array detection demonstrated the specificity of the method in the presence of degradants. The degradation products were well resolved from primary peak of darunavir, indicating that the method is specific and stability-indicating. The HPLC method was validated as per International Conference on Harmonization guidelines with respect to specificity, precision, linearity, accuracy and robustness. Regression analysis showed a correlation coefficient value greater than 0.999. The accuracy of the method was established based on the recovery obtained for darunavir ethanolate.

  6. Comparative determination of sibutramine as an adulterant in natural slimming products by HPLC and HPTLC densitometry.

    Science.gov (United States)

    Ariburnu, Etil; Uludag, Mehmet Fazli; Yalcinkaya, Huseyin; Yesilada, Erdem

    2012-05-01

    A new validated method for the identification and quantification of the sibutramine was developed by HPTLC-densitometry at 225 nm and advantages and disadvantages compared with HPLC-FLD at 225 nm emission and 316 nm excitation. Both methods were applied to the analysis of three natural slimming products in the market for the quantitative analysis of illegally added sibutramine. HPTLC separations were performed on (20 cm × 10 cm) glass HPTLC plates coated with silica gel 60 F(254) using a mobile phase, n-hexane-acetone-ammonia (10:1:0.1, v/v/v). For HPLC analysis, a phenyl column (5.0 μm, 150 mm × 4.6 mm, i.d.) and an isocratic mobile phase of acetonitrile-water-formic acid (pH 3.0; 0.19M) (45:55:0.78, v/v/v) was used. The calibration curve area versus concentration was found to be linear in the range of 250-2000 ng/spot(-1) and 5-200 μg/ml for HPTLC and HPLC, respectively. Both methods were validated for accuracy, precision, linearity, selectivity, recovery and short term stability. As a conclusion, these methods were found to be useful for the routine analysis of illegally added sibutramine in the marketed products. Copyright © 2012 Elsevier B.V. All rights reserved.

  7. Simultaneous Speciation of Arsenic, Selenium, and Chromium by HPLC-ICP-MS

    Science.gov (United States)

    Wolf, Ruth E.; Morman, Suzette A.; Morrison, Jean M.; Lamothe, Paul J.

    2008-01-01

    An adaptation of an analytical method developed for chromium speciation has been utilized for the simultaneous determination of As(III), As(V), Se(IV), Se(VI), Cr(III), and Cr(VI) species using high performance liquid chromatography (HPLC) separation with ICP-MS detection. Reduction of interferences for the determination of As, Se, and Cr by ICP-MS is a major consideration for this method. Toward this end, a Dynamic Reaction Cell (DRC) ICP-MS system was used to detect the species eluted from the chromatographic column. A variety of reaction cell gases and conditions may be utilized, and the advantages and limitations of the gases tested to date will be presented and discussed. The separation and detection of the As, Se, and Cr species of interest can be achieved using the same chromatographic conditions in less than 2 minutes by complexing the Cr(III) with EDTA prior to injection on the HPLC column. Practical aspects of simultaneous speciation analysis will be presented and discussed, including issues with HPLC sample vial contamination, standard and sample contamination, species stability, and considerations regarding sample collection and preservation methods. The results of testing to determine the method's robustness to common concomitant element and anion effects will also be discussed. Finally, results will be presented using the method for the analysis of a variety of environmental and geological samples including waters, soil leachates and simulated bio-fluid leachates.

  8. [Correlation of HPLC Characteristic Spectra of Vinegar Corydalis Rhizoma Decoction Pieces, Water Decoction and Formula Granules].

    Science.gov (United States)

    Wei, Mei; Du, Lan-zhe; Li, Hui; Zhang, Guang-da; Chen, Xiang-dong

    2015-05-01

    To study the correlation of characteristic spectra of Vinegar Corydalis Rhizoma decoction pieces, water decoction and formula granules by HPLC, and to investigate the transfer of the main chemical constituents between three different forms. The analysis was carried out by a Phenomenex Gemini C18 column (250 mm x 4.6 mm,5 μm) with acetonitrile-1% acetic acid and ammonium acetate buffer solution (pH 6.0) as the mobile phase in a gradient elution mode. The detection wavelength was 280 nm with a flow rate of 0.8 mL /min. The column temperature was 30 degrees C. The characteristic spectra from 11 batches of Vinegar Corydalis Rhizoma decoction pieces, 11 batches of water decoction and 11 batches of formula granules were established respectively. Ten peaks in the HPLC characteristic spectra from 11 batches of formula granules could be tracked in the water decoction, nine peaks in the HPLC characteristic spectra could be tracked in the decoction pieces. In the ten common peaks, four components such as protopine, palnatine chloride, berberine hydrochloride and tetrahydropalmatine were verified. The main chemical components of Vinegar Corydalis Rhizoma decoction pieces, water decoction and formula granules are basically the same, the common component contents have similar proportion.

  9. Monitoring of atrazine in milk using a rapid tube-based ELISA and validation with HPLC.

    Science.gov (United States)

    Barchanska, Hanna; Jodo, Elzbieta; Price, Robert Graham; Baranowska, Irena; Abuknesha, Ramadan

    2012-06-01

    Although atrazine has been banned in the European Union since 2007 it still persists in soil from where it can enter the food chain. Milk-producing animals accumulate atrazine from contaminated feed and water and since large quantities of milk and milk products are consumed its quality should be constantly monitored. The objective of this investigation was to develop a simple tube ELISA procedure suitable for use in non-specialised laboratories and in the field. A polyclonal antibody raised in sheep and the hapten-gelatine conjugate was immobilised onto polystyrene tubes. This enables the colour produced to be read on a basic spectrophotometer. Milk samples were collected from three farms in different regions of Poland and diluted before immunoassay was performed. Samples were extracted with hexane-acetone for HPLC analysis. The amount of fat in the milk samples interferes with the dose response so it essential that the standards are prepared in the same samples matrix. A good correlation between 1% and 2% was found between the two methods in the analysis of real samples. However the ELISA procedure was more sensitive that the HPLC method since atrazine was detected in some samples by the ELISA but was not confirmed by the HPLC method. The study demonstrated that the simple antigen-coated tube assay provides a cost effective and valuable screening test that can be easily modified for direct use as a screening tool in the field. Copyright © 2012. Published by Elsevier Ltd.

  10. Determination of Bovine Lactoferrin in Food by HPLC with a Heparin Affinity Column for Sample Preparation.

    Science.gov (United States)

    Zhang, Yin; Lou, Fei; Wu, Wei; Dong, Xin; Ren, Jia; Shen, Qiuguang

    2017-01-01

    An HPLC method was developed for the quantitative determination of bovine lactoferrin (bLF) in sterilized milk, modified milk, fermented milk, infant formula, adult formula, rice cereal, vitamin function drink, and protein powder products. bLF was first extracted with a phosphate buffer (pH 8), underwent cleanup in a heparin affinity column, and was detected by HPLC with a C4 column and diode-array detector at a wavelength of 280 nm. The proposed method provided a linear detection range of 10.0-1000 μg/mL with an LOD of 0.6 mg/100 g in liquid samples and 3 mg/100 g in solid samples and an LOQ of 2 mg/100 g in liquid samples and 10 mg/100 g in solid samples. In addition, the method showed good recovery for various samples, ranging from 76 to 96%. The method had several remarkable advantages, including ease of handling, high sensitivity and accuracy, good reproducibility, and low-cost detection. Based on the distinctive properties presented here, we believe the proposed HPLC assay holds great promise for the oversight and detection of bLF in testing organizations, dairy enterprises, and regulatory authorities.

  11. Simultaneous quantitative determination of five alkaloids in Catharanthus roseus by HPLC-ESI-MS/MS.

    Science.gov (United States)

    Zhang, Lin; Gai, Qing-Hui; Zu, Yuan-Gang; Yang, Lei; Ma, Yu-Liang; Liu, Yang

    2014-10-01

    To establish a method to simultaneously determine the main five alkaloids of Catharanthus roseus for trace samples, a high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry (HPLC-ESI-MS/MS) analysis method was developed. The five Catharanthus alkaloids, vinblastine, vincristine, vinleurosine, vindoline, and catharanthine were chromatographically separated on a C18 HPLC column. The mobile phase was methanol-15 nmol·L(-1) ammonium acetate containing 0.02% formic acid (65 : 35, V/V). The quantification of these alkaloids was based on the Multiple Reaction Monitoring (MRM) mode. This method was validated, and the results achieved the aims of the study. The intra- and inter-day precision and accuracy of the five alkaloids were within 1.2%-11.5% (RSD%) and -10.9%-10.5% (RE%). The recovery rates of the five alkaloids of samples were from 79.9% to 91.5%. The five analytes were stable at room temperature for 2 h, at 4 °C for 12 h, and at -20 °C for two weeks. The developed method was applied successfully to determine the content of the five alkaloids in three plant parts of three batches of C. roseus with a minute amount collected from three regions of China. The HPLC-ESI-MS/MS method can be used for the simultaneous determination of five important alkaloids in trace C. roseus samples. Copyright © 2014 China Pharmaceutical University. Published by Elsevier B.V. All rights reserved.

  12. A nitromethane-based HPLC system alternative to acetonitrile for carotenoid analysis of fruit and vegetables.

    Science.gov (United States)

    Sandmann, Gerhard

    2010-01-01

    Acetonitrile-based HPLC systems are the most commonly used for carotenoid analysis from different plant tissues. Because of the acetonitrile shortage, an HPLC system for the separation of carotenoids on C(18) reversed-phase columns was developed in which an acetonitrile-alcohol-based mobile phase was replaced by nitromethane. This solvent comes closest to acetonitrile with respect to its elutrophic property. Our criterion was to obtain similar separation and retention times for a range of differently structured carotenoids. This was achieved by further increase in the lipophilicity with ethylacetate. For all the carotenoids which we tested, we found co-elution only of β-cryptoxanthin and lycopene. By addition of 1% of water, separation of this pair of carotenoids was also achieved. The final recommended mobile phase consisted of nitromethane : 2-propanol : ethyl acetate : water (79 : 10 : 10 : 1, by volume). On Nucleosil C(18) columns and related ones like Hypersil C(18), we obtained separation of carotenes, hydroxyl, epoxy and keto derivatives, which resembles the excellent separation properties of acetonitrile-based mobile phases on C(18) reversed phase columns. We successfully applied the newly developed HPLC system to the separation of carotenoids from different vegetables and fruit. Copyright © 2010 John Wiley & Sons, Ltd.

  13. Fast and calibration free determination of first order reaction kinetics in API synthesis using in-situ ATR-FTIR.

    Science.gov (United States)

    Rehbein, Moritz C; Husmann, Sascha; Lechner, Christian; Kunick, Conrad; Scholl, Stephan

    2017-09-28

    In early stages of drug development only sparse amounts of the key substances are available, which is problematic for the determination of important process data like reaction kinetics. Therefore, it is important to perform experiments as economically as possible, especially in regards to limiting compounds. Here we demonstrate the use of a temperature step experiment enabling the determination of complete reaction kinetics in a single non-isothermal experiment. In contrast to the traditionally used HPLC, the method takes advantage of the high measuring rate and the low amount of labor involved in using in-situ ATR-FTIR to determine time-dependent concentration-equivalent data. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Kinetic behaviour in supercritical fluid chromatography with modified mobile phase for 5 μm particle size and varied flow rates.

    Science.gov (United States)

    Lesellier, E; Fougere, L; Poe, Donald P

    2011-04-15

    After much development of stationary phase chemistry, in recent years the focus of many studies in HPLC has shifted to increase the efficiency and analysis speed. Ultra high pressure liquid chromatography (UHPLC) using sub-2 μm particles, and high temperature liquid chromatography (HTLC), using temperatures above 100°C have received much attention. These new approaches allow the use of flow rates higher than those classically used in HPLC, reducing the analysis duration. Due to the low viscosity of supercritical fluids, high velocities, i.e. high flow rates, can be achieved with classical pumping systems typically used in supercritical fluid chromatography (SFC). The effects of the flow rate increase with CO(2)/methanol mobile phase was studied on the inlet pressure, t(0), the retention factor of the compounds, and on the efficiency. Simple comparisons of efficiencies obtained at varied temperature between SFC and HPLC, with a packed column containing 5 μm particles, show the greater kinetic performances achieved with the CO(2)/methanol fluid, and underline specific behaviours of SFC, occurring for high flow rates and sub-ambient temperature. Some values (N/t(0)) are also compared to UHPLC data, showing that good performance can be achieved in SFC without applying drastic analytical conditions. Finally, simple kinetic plots (t(0) vs N) at constant column length are used to select combinations of temperature and flow rate necessary to achieve a required theoretical plate number. Copyright © 2010 Elsevier B.V. All rights reserved.

  15. Kinetic Quantum Theory of Gravity

    CERN Document Server

    DeAquino, F

    2002-01-01

    Gravity is here quantized starting from the generalization of the action function. This leads to an equation of correlation between gravitational and inertial masses, which depends on the particle's kinetic energy. We show that there is a reaffirmation of the strong equivalence principle and consequently the Einstein's equations are preserved. In fact such equations are deduced here directly from this kinetic approach to Gravity. Moreover, we have obtained a generalized equation for inertial forces, which incorporates the Mach's principle into Gravitation. Also, we have deduced the equation of Entropy; the Hamiltonian for a particle in an electromagnetic field and the reciprocal fine structure constant. It is possible to deduce the expression of the Casimir force and also to explain the Inflation Period and the Missing Matter without assuming the existence of vacuum fluctuations. This new approach for Gravity will allow us to understand some crucial matters in Cosmology.

  16. Kinetic Quantum Theory of Gravity

    CERN Document Server

    DeAquino, F

    2002-01-01

    Starting from the action function we have derived a theoretical background that leads to quantization of gravity and the deduction of a correlation between the gravitational and inertial masses, which depends on the kinetic momentum of the particle. We show that there is a reaffirmation of the strong equivalence principle and consequently the Einstein's equations are preserved. In fact such equations are deduced here directly from this kinetic approach to Gravity. Moreover, we have obtained a generalized equation for inertial forces, which incorporates the Mach's principle into Gravitation. Also, we have deduced the equation of Entropy; the Hamiltonian for a particle in an electromagnetic field and the reciprocal fine structure constant. It is possible to deduce the expression of the Casimir force and also to explain the Inflation Period and the Missing Matter without assuming the existence of vacuum fluctuations. This new approach for Gravity will allow us to understand some crucial matters in Cosmology.

  17. Kinetic approach to relativistic dissipation

    Science.gov (United States)

    Gabbana, A.; Mendoza, M.; Succi, S.; Tripiccione, R.

    2017-08-01

    Despite a long record of intense effort, the basic mechanisms by which dissipation emerges from the microscopic dynamics of a relativistic fluid still elude complete understanding. In particular, several details must still be finalized in the pathway from kinetic theory to hydrodynamics mainly in the derivation of the values of the transport coefficients. In this paper, we approach the problem by matching data from lattice-kinetic simulations with analytical predictions. Our numerical results provide neat evidence in favor of the Chapman-Enskog [The Mathematical Theory of Non-Uniform Gases, 3rd ed. (Cambridge University Press, Cambridge, U.K., 1970)] procedure as suggested by recent theoretical analyses along with qualitative hints at the basic reasons why the Chapman-Enskog expansion might be better suited than Grad's method [Commun. Pure Appl. Math. 2, 331 (1949), 10.1002/cpa.3160020403] to capture the emergence of dissipative effects in relativistic fluids.

  18. Morphogenesis of Kinetic Reciprocal Frames

    DEFF Research Database (Denmark)

    Parigi, Dario; Sassone, Mario

    2011-01-01

    Kinetic structures in civil engineering and architecture gained considerable more attention in the very recent years as a practical solution to face time dependant performances. Realized projects are mostly bridges, retractable roofs, while in architecture the trend follows the category of intera......Kinetic structures in civil engineering and architecture gained considerable more attention in the very recent years as a practical solution to face time dependant performances. Realized projects are mostly bridges, retractable roofs, while in architecture the trend follows the category...... (RF) were studied in the past as a practical solution to span distances with shorter elements. Leonardo da Vinci discovered interesting RF patterns and studied three dimensional arch structures for bridges. RF are generally defined as structures that forms closed circuits of forces, and where elements...

  19. Art Engineering and Kinetic Art

    Directory of Open Access Journals (Sweden)

    Barış Yılmaz

    2014-12-01

    Full Text Available Performing an art, either by painting or by sculpturing, requires to be interdisciplinary. When an artist creates his/her work of art, the process he/she realizes is supported by different engineering disciplines. Therefore, especially modern artists need to understand engineering science and this results in transforming artists into engineers. Opportunities provided by technology and science enable artists to expand his/her vision and to improve his/her works. Especially kinetic art has become an approach that combines art with engineering. Kinetic art, which is nourished with varied disciplines, is an excellent example to prove that art is interdisciplinary and to show the relationship between artist/art and engineering.

  20. Unfolding Kinetics of Egg Protein

    Science.gov (United States)

    Sharma, Dipti

    2011-03-01

    This study explores denaturing kinetics of egg white using high resolution calorimetric technique. Fresh egg was scanned fro heating and cooling to see the thermodynamics 10circ; C to 100circ; C at different heating ramp rates varying from 1 to 20circ; C/min. An endothermic peak was found on heating scan showing denaturing of protein which was found absent at the cooling indicating the absence of any residue after heating. The denature peak shifted towards higher temperature as ramp rate increases following Arrhenius behavior and shows an activated denaturing kinetics of the egg protein. This peak was also compared with the water to avoid water effects. Behavior of denaturing peak can be explained in terms of Arrhenius theory.

  1. Kinetic ELISA in Microfluidic Channels

    Directory of Open Access Journals (Sweden)

    Debashis Dutta

    2011-06-01

    Full Text Available In this article, we describe the kinetic ELISA of Blue Tongue and Epizootic Hemorrhagic Disease viral antibodies in microfluidic channels by monitoring the rate of generation of the enzyme reaction product under static conditions. It has been shown that this format of the immunoassay allows very reliable quantitation of the target species using inexpensive glass microchips and a standard epifluorescence microscope system coupled to a CCD camera. For the viral antibodies assayed here, the limit of detection (LOD for the analyte concentration in our microchips was established to be 3–5 times lower than that obtained on commercial microwell plates using a fiftieth of the sample volume and less than a third of the incubation time. Our analyses further show that when compared to the end-point ELISA format, the kinetic mode of this assay yields an improvement in the LOD by over an order of magnitude in microfluidic devices. This benefit is primarily realized as the observed variation in the background fluorescence (signal at the start of the enzyme reaction period was significantly larger than that in the rate of signal generation upon repeating these assays in different microchannels/microchips. Because the kinetic ELISA results depend only on the latter quantity, the noise level in them was substantially lower compared to that in its end-point counterpart in which the absolute fluorescence measurements are of greater significance. While a similar benefit was also recorded through implementation of kinetic ELISAs on the microwell platform, the improvement in LOD registered in that system was not as significant as was observed in the case of microfluidic assays.

  2. UV–VIS and HPLC studies on Amphiroa anceps (Lamarck Decaisne

    Directory of Open Access Journals (Sweden)

    Johnson Marimuthu (a Antonisamy

    2016-09-01

    Full Text Available The present study was aimed to explore phytochemical constituents present in Amphiroa anceps (Lamarck Decaisne. The extracts of A. anceps were scanned in the wavelength ranging from 200 to 1100 nm by using Shimadzu Spectrophotometer. HPLC method was performed on a Shimadzu LC-10 AT VP HPLC system, which was equipped with a model LC-10AT pump, UV–VIS detector SPD-10AT, Rheodyne injector fitted with a 20 μl loop and auto injector SIL-10AT. Out of 156 (2 × 6 × 13 = 156 tests for the presence or absence of the above compounds, 42 tests gave positive results and the remaining 114 showed negative results. The 42 positive results showed the presence of alkaloids, steroids, phenolic groups, saponins, tannin, flavonoids, terpenoids, glycosides, proteins and sugars. The results of the ash analysis discovered the existence of sulphur, calcium, magnesium, iron, phosphorous and chlorine in all the extracts of A. anceps. The UV–VIS profile of A. anceps benzene extracts showed peaks at 670, 612, 536, 504, and 412 nm with the absorption 2.004, 0.333, 0.417, 0.608 and 3.311. The UV–VIS profile of A. anceps chloroform extracts showed the peaks at 666, 608, 538, 502 and 416 nm with the absorption 1.029, 0.39, 0.458, 0.552 and 2.648. The qualitative UV–VIS spectrum profile of A. anceps methanolic extracts showed peaks at 656 and 330 nm with the absorption 0.295 and 3.656. The HPLC profile of A. anceps aqueous extracts showed two prominent peaks at a retention time of 1.737 and 2.680 min and some moderate peaks were observed with the retention time 4.083, 6.387 and 1.490 min. The qualitative HPLC fingerprint profile of isopropanol extract of A. anceps showed one prominent peak at a retention time of 2.673 min. The HPLC profile of A. anceps methanolic extracts illustrated two prominent peaks at a retention time of 1.927 and 2.667 min and some moderate peaks were also observed with the retention time 2.347, 4.077 and 5.873 min, respectively.

  3. Degradation kinetic modelling of ascorbic acid and colour intensity in pasteurised blood orange juice during storage.

    Science.gov (United States)

    Remini, Hocine; Mertz, Christian; Belbahi, Amine; Achir, Nawel; Dornier, Manuel; Madani, Khodir

    2015-04-15

    The stability of ascorbic acid and colour intensity in pasteurised blood orange juice (Citrus sinensis [L.] Osbeck) during one month of storage was investigated at 4-37 °C. The effects of ascorbic acid fortification (at 100, 200 mg L(-1)) and deaeration, temperature/time storage on the kinetic behaviour were determined. Ascorbic acid was monitored by HPLC-DAD and colour intensity by spectrophotometric measurements. Degradation kinetics were best fitted by first-order reaction models for both ascorbic acid and colour intensity. Three models (Arrhenius, Eyring and Ball) were used to assess the temperature-dependent degradation. Following the Arrhenius model, activation energies were ranged from 51 to 135 kJ mol(-1) for ascorbic acid and from 49 to 99 kJ mol(-1) for colour intensity. The effect of storage temperature and deaeration are the most influent factors on kinetics degradation, while the fortification revealed no significant effect on ascorbic acid content and colour intensity. Copyright © 2014 Elsevier Ltd. All rights reserved.

  4. Kinetic and thermodynamic investigation of mancozeb degradation in tomato homogenate during thermal processing.

    Science.gov (United States)

    Certel, Muharrem; Cengiz, Mehmet F; Akçay, Mehmet

    2012-02-01

    The kinetic and thermodynamic parameters of mancozeb degradation in tomato homogenates under the conditions prevailing in the manufacture of tomato products (at 60-100 °C for 0-60 min) were investigated. A gas chromatography-mass spectrometry method was used to analyse residual mancozeb in tomato homogenate. Ethylenethiourea (ETU), the main toxic degradation product of mancozeb, was measured by high-performance liquid chromatography (HPLC)-with photodiode array detector (PDA). The degradation of mancozeb and the formation of ETU in tomato homogenates were adequately described as first-order kinetics. Dependence of the rate constant followed the Arrhenius relationship. Apparent activation energies, temperature coefficients, half time and time to reduce to 90% of the initial value of mancozeb were calculated as kinetic parameters. The thermodynamic parameters of mancozeb were also described as Δg(d) = - 2.440 and 7.074 kJ mol⁻¹; Δh(d) = - 32.555 and - 42.767 kJ mol⁻¹; Δs(d) = - 0.090 and - 0.150 kJ mol⁻¹ K⁻¹; K(e) = 0.414 and 9.797 L g⁻¹ for 333 and 373 K respectively. Current findings may shed light on the reduction of mancozeb residue and its toxic degradation product during thermal processing of tomatoes and may also be valuable in awareness and prevention of potential risks from dietary exposure. Copyright © 2011 Society of Chemical Industry.

  5. Nonextensive kinetics of fluorescence resonance energy transfer.

    Science.gov (United States)

    Rolinski, Olaf J; Birch, David J S

    2008-10-14

    Some fluorescence dyes in complex media, such as those found in biology, demonstrate nonextensive kinetics, which implies representing their fluorescence decays in terms of lifetime distributions rather than simple exponentials. Complex kinetics usually discourage application to lifetime sensors, as it is believed, that additional molecular mechanisms employed for detection of an analyte will make the resulting kinetics ambiguous and the sensor response inconclusive. In this paper we investigate theoretically the applicability of complex dye kinetics as a fluorescence resonance energy transfer based lifetime sensor and demonstrate that the nonextensive nature of its kinetics does not decrease the sensing performance, and indeed even provides richer structural information than a simple exponential behavior.

  6. Kinetic Algorithms for Harbour Management

    Science.gov (United States)

    Gold, C. M.; Goralski, R. I.

    2012-07-01

    Modern harbour management for a busy port needs to resolve a variety of simultaneous problems. Harbour traffic may be busy and the waterways congested, both by the major shipping and by the attendant harbour tugs. The harbour channel may be narrow and tortuous, and rapidly changing tides may require frequent course adjustments. Navigation aids must be clearly specified and immediately identifiable, in order to permit safe passage for the vessels. This requires a GIS with attributes not easily available with traditional products. The GeoVS system is a kinetic GIS with full three-dimensional visualisation, so that ships, bathymetry and landscape may be viewed in a form that is immediately understandable to both harbour pilots and the harbour authority. The system is kinetic because the data structures used to preserve the topological relationships between ships, seafloor and coastline are able to be maintained on a real-time basis, taking account of ship movement recorded on the compulsory AIS (Automatic Information System) beacons. Maintenance of this real-time topology allows for easy detection of potential collisions, as well as real-time bathymetric estimations, necessary to prevent ship grounding in highly tidal environments. The system, based on previous research into kinetic Voronoi diagrams, as well as development of a completely new graphical engine, is now in commercial production, where its advantages over simpler twodimensional models without automatic collision and grounding detection are becoming evident. Other applications are readily envisaged, and will be addressed in the near future.

  7. KINETIC ALGORITHMS FOR HARBOUR MANAGEMENT

    Directory of Open Access Journals (Sweden)

    C. M. Gold

    2012-07-01

    Full Text Available Modern harbour management for a busy port needs to resolve a variety of simultaneous problems. Harbour traffic may be busy and the waterways congested, both by the major shipping and by the attendant harbour tugs. The harbour channel may be narrow and tortuous, and rapidly changing tides may require frequent course adjustments. Navigation aids must be clearly specified and immediately identifiable, in order to permit safe passage for the vessels. This requires a GIS with attributes not easily available with traditional products. The GeoVS system is a kinetic GIS with full three-dimensional visualisation, so that ships, bathymetry and landscape may be viewed in a form that is immediately understandable to both harbour pilots and the harbour authority. The system is kinetic because the data structures used to preserve the topological relationships between ships, seafloor and coastline are able to be maintained on a real-time basis, taking account of ship movement recorded on the compulsory AIS (Automatic Information System beacons. Maintenance of this real-time topology allows for easy detection of potential collisions, as well as real-time bathymetric estimations, necessary to prevent ship grounding in highly tidal environments. The system, based on previous research into kinetic Voronoi diagrams, as well as development of a completely new graphical engine, is now in commercial production, where its advantages over simpler twodimensional models without automatic collision and grounding detection are becoming evident. Other applications are readily envisaged, and will be addressed in the near future.

  8. An automated HPLC method to determine intracellular vincristine concentrations in mononuclear cells of children with acute lymphoblastic leukemia

    NARCIS (Netherlands)

    Groninger, E; Koopmans, P; Kamps, W; Uges, D

    A method to determine intracellular vincristine concentrations in vivo in leukemic cells of patients is useful to investigate mechanisms of vincristine resistance. We developed a high-performance liquid chromatographic (HPLC) method to measure vincristine concentrations in human mononuclear cells

  9. INTERFERENCE OF CARBAMYLATED AND ACETYLATED HEMOGLOBINS IN ASSAYS OF GLYCOHEMOGLOBIN BY HPLC, ELECTROPHORESIS, AFFINITY-CHROMATOGRAPHY, AND ENZYME-IMMUNOASSAY

    NARCIS (Netherlands)

    WEYKAMP, CW; PENDERS, TJ; SIEBELDER, CWM; MUSKIET, FAJ; VANDERSLIK, W

    In vitro-synthesized carbamylated and acetylated hemoglobins interfered in assays of glycohemoglobin by HPLC and electrophoresis but had no effects on results obtained by affinity chromatography and enzyme immunoassay. Correlations between long-term serum urea concentrations and glycohemoglobin

  10. Residuen van anabolica in toedieningsplaatsen bij slachtdieren. II Specifieke identificatie van anabolica met HPLC-diode array detectie

    NARCIS (Netherlands)

    van Blitterswijk H; Jansen EHJM; Stephany RW

    1985-01-01

    De combinatie hoge druk vloeistofchromatografie (HPLC) met in situ totale ultraviolet (UV) spectrumdetectie via het "diode array principe", wordt nader beschreven en geevalueerd. Een relatief grote hoeveelheid stof (circa 200 nanogram) is benodigd voor spectrum identificatie. Voor

  11. Highly sensitive and specific analysis of sterol profiles in biological samples by HPLC-ESI-MS/MS.

    Science.gov (United States)

    Honda, Akira; Miyazaki, Teruo; Ikegami, Tadashi; Iwamoto, Junichi; Yamashita, Kouwa; Numazawa, Mitsuteru; Matsuzaki, Yasushi

    2010-08-01

    High-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) is a powerful method for the microanalysis of compounds in biological samples. Compared with gas chromatography-mass spectrometry (GC-MS), this method is more broadly applicable to various compounds and usually does not require a derivatization step before analysis. However, when neutral sterols are analyzed, the sensitivities of usual HPLC-MS/MS method are not superior to those of GC-MS because the sterols are relatively resistant to ionization. In this review, we introduce the recent development of HPLC-MS/MS analysis for the quantification of non-cholesterol sterols. By adding an effective derivatization step to the conventional procedure, sterol analysis by HPLC-MS/MS surpassed that obtained by GC-MS in sensitivity. In addition, sufficient specificity of this method was achieved by selected reaction monitoring (SRM) and thorough chromatographic separation of each sterol. Copyright 2010 Elsevier Ltd. All rights reserved.

  12. Quantifying nanomolar levels of nitrite in biological samples by HPLC-Griess method: special reference to arterio-venous difference in vivo.

    Science.gov (United States)

    Ishibashi, Takaharu; Miwa, Tomoko; Shinkawa, Ikumi; Nishizawa, Naoki; Nomura, Mihoko; Yoshida, Junko; Kawada, Tomie; Nishio, Matomo

    2008-05-01

    Nitrite (NO(2)(-)) is assumed to play an important role in regulation of vascular tone as a reservoir of nitric oxide (NO). To examine its physiological contribution, however, a sensitive method is required for determination of the true level of NO(2)(-) in biological samples. To this end, practical consideration to avoid NO(2)(-) contamination through the quantification procedure is important. We present here a highly sensitive and accurate method for determining NO(2)(-) in plasma by improving the HPLC-Griess system with minimal NO(2)(-) contamination in the samples. The system achieved high sensitivity (detection limit of 2 nM and sensitivity to 1 nM) and complete separation of the NO(2)(-) signal peak by modifying the system setup and mobile phase. Using this method, we achieved acceptable quantification of low NO(2)(-) levels in plasma. Deproteinization by ultrafiltration and exposure to atmosphere before measurement were identified as the major sources of NO(2)(-) contamination during sample processing. We addressed these issues by the use of methanol for deproteinization and gas-tight caps. These countermeasures allowed us to detect small arterio-venous NO(2)(-) differences in rabbit plasma that may indicate kinetic difference of NO(2)(-) in a small number of samples (n = 6). This difference became prominent when NO(2)(-) or a NO releasing agent, NOR1, was intravenously applied. Our results indicate that application of a sensitive method with careful handling is important for accurate determination of NO(2)(-) and that our method is applicable for further examination of the kinetic features of NO(2)(-) in vivo.

  13. Photocatalytic degradation kinetics and mechanism of antivirus drug-lamivudine in TiO{sub 2} dispersion

    Energy Technology Data Exchange (ETDEWEB)

    An, Taicheng, E-mail: antc99@gig.ac.cn [State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Resources Utilization and Protection, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China); An, Jibin [State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Resources Utilization and Protection, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China); College of Petrochemical Technology, Lanzhou University of Technology, Lanzhou 730050 (China); Graduate School of Chinese Academy of Sciences, Beijing 100049 (China); Yang, Hai [State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Resources Utilization and Protection, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China); Graduate School of Chinese Academy of Sciences, Beijing 100049 (China); Li, Guiying [State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Resources Utilization and Protection, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China); Feng, Huixia [College of Petrochemical Technology, Lanzhou University of Technology, Lanzhou 730050 (China); Nie, Xiangping [Institute of Hydrobiology, Jinan University, Guangzhou 510632 (China)

    2011-12-15

    Highlights: Black-Right-Pointing-Pointer Photocatalytic degradation kinetics of antivirus drug lamivudine. Black-Right-Pointing-Pointer The degradation kinetics was optimized by the single-variable-at-a-time. Black-Right-Pointing-Pointer The degradation kinetics was optimized by central composite design. Black-Right-Pointing-Pointer The contribution of reactive species was investigated with addition of scavengers. Black-Right-Pointing-Pointer Six intermediates were identified and a degradation mechanism was proposed. - Abstract: Photocatalytic degradation kinetics of antivirus drug-lamivudine in aqueous TiO{sub 2} dispersions was systematically optimized by both single-variable-at-a-time and central composite design based on the response surface methodology. Three variables, TiO{sub 2} content, initial pH and lamivudine concentration, were selected to determine the dependence of degradation efficiencies of lamivudine on independent variables. Response surface methodology modeling results indicated that degradation efficiencies of lamivudine were highly affected by TiO{sub 2} content and initial lamivudine concentration. The highest degradation efficiency was achieved at suitable amount of TiO{sub 2} and with maintaining initial lamivudine concentration to a minimum. In addition, the contribution experiments of various primary reactive species produced during the photocatalysis were investigated with the addition of different scavengers and found that hydroxyl radicals was the major reactive species involved in lamivudine degradation in aqueous TiO{sub 2}. Six degradation intermediates were identified using HPLC/MS/MS, and photocatalytic degradation mechanism of lamivudine was proposed by utilizing collective information from both experimental results of HPLC/MS/MS, ion chromatography as well as total organic carbon and theoretical data of frontier electron densities and point charges.

  14. Screening and Identifying Antioxidative Components in Ginkgo biloba Pollen by DPPH-HPLC-PAD Coupled with HPLC-ESI-MS2.

    Directory of Open Access Journals (Sweden)

    Jiying Qiu

    Full Text Available The Ginkgo biloba is one of ancient trees that exists from billions of years ago, its leaf and nut are used as herbs and foods in China, while so far its pollen does not have any application except pollination. In order to evaluate the antioxidant activity of Ginkgo biloba pollen, and rapidly screen its antioxidative components, the 1,1-diphenyl-2-picrylhydrazyl (DPPH scavenging ability, total flavonoid, total phenol, and proanthocyanidin of Ginkgo biloba pollen were determined and compared with those of Ginkgo biloba leaf and nut, and the off-line DPPH-HPLC-PAD and HPLC-ESI-MS2 were applied for screening and identifying the antioxidant flavonoids in Ginkgo biloba pollen. The results showed that the DPPH scavenging ability of Ginkgo biloba pollen was much higher than Ginkgo biloba nut, but lower than Ginkgo biloba leaf, while the total content of flavonoid in Ginkgo biloba pollen was approximately 4.37 times higher than in Ginkgo biloba leaf. Further studies found that the major flavonol aglycone in Ginkgo biloba pollen was kaempferol, which accounted for 96.71% of the total aglycones (includes quercetin, kaempferol and isorhamnetin, and the main flavonoid components in Ginkgo biloba pollen were flavonoid glycosides. Finally, ten antioxidant peaks were screened and identified to be flavonoids (including kaempferol and nine flavonoid glycosides, so flavonoids were likely to be the main antioxidant components in GP, and among them, three novel kaempferol glycosides (peaks 1, 2, and 3 were found in Ginkgo biloba pollen for the first time, which had never been found in Ginkgo biloba.

  15. Screening and Identifying Antioxidative Components in Ginkgo biloba Pollen by DPPH-HPLC-PAD Coupled with HPLC-ESI-MS2.

    Science.gov (United States)

    Qiu, Jiying; Chen, Xiangyan; Netrusov, A I; Zhou, Qingxin; Guo, Danyang; Liu, Xiaoyong; He, Hailun; Xin, Xue; Wang, Yifen; Chen, Leilei

    2017-01-01

    The Ginkgo biloba is one of ancient trees that exists from billions of years ago, its leaf and nut are used as herbs and foods in China, while so far its pollen does not have any application except pollination. In order to evaluate the antioxidant activity of Ginkgo biloba pollen, and rapidly screen its antioxidative components, the 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging ability, total flavonoid, total phenol, and proanthocyanidin of Ginkgo biloba pollen were determined and compared with those of Ginkgo biloba leaf and nut, and the off-line DPPH-HPLC-PAD and HPLC-ESI-MS2 were applied for screening and identifying the antioxidant flavonoids in Ginkgo biloba pollen. The results showed that the DPPH scavenging ability of Ginkgo biloba pollen was much higher than Ginkgo biloba nut, but lower than Ginkgo biloba leaf, while the total content of flavonoid in Ginkgo biloba pollen was approximately 4.37 times higher than in Ginkgo biloba leaf. Further studies found that the major flavonol aglycone in Ginkgo biloba pollen was kaempferol, which accounted for 96.71% of the total aglycones (includes quercetin, kaempferol and isorhamnetin), and the main flavonoid components in Ginkgo biloba pollen were flavonoid glycosides. Finally, ten antioxidant peaks were screened and identified to be flavonoids (including kaempferol and nine flavonoid glycosides), so flavonoids were likely to be the main antioxidant components in GP, and among them, three novel kaempferol glycosides (peaks 1, 2, and 3) were found in Ginkgo biloba pollen for the first time, which had never been found in Ginkgo biloba.

  16. A Validated Stability-Indicating HPLC Method for Routine Analysis of an Injectable Lincomycin and Spectinomycin Formulation

    OpenAIRE

    Abualhasan,Murad; Batrawi, Nidal; SUTCLIFFE, Oliver; ZAID, Abdel

    2012-01-01

    Lincomycin and spectinomycin combination therapy is widely used in veterinary medicine for the treatment of gastrointestinal and respiratory infections caused by lincomycin- and spectinomycin-sensitive microorganisms. A simple, reverse phase HPLC method for the analysis of samples of an injectable lincomycin and spectinomycin preparation containing a mixture of inactive excipients has been developed. The HPLC was carried out using the RP-C18 (250 mm × 4.0 mm, 5 μm) column, with the gradient m...

  17. DEVELOPMENT OF ASSAY METHOD AND FORCED DEGRADATION STUDY OF LEDIPASVIR AND SOFOSBUVIR BY RP-HPLC IN TABLET FORMULATION

    OpenAIRE

    S. Naazneen*, A. Sridevi

    2017-01-01

    Chronic hepatitis C virus (HCV) infection is one of the most common etiologies of liver-related mortality throughout the world. Sofosbuvir and ledipasvir are inhobits HCV NS5B and HCV NS5A polymerase respectively. No published LC-MS/MS and HPLC based methods for simultaneous estimation of ledipasvir and sofosbuvir. Therefore, A stability indicating high performance liquid Chromatographic (HPLC) method was developed and validated for estimation of both drugs. Chromatographic separation was ach...

  18. ALKYLARYLKETONE HOMOLOGOUS SERIES FOR DETERMINATION OF KOVATS RETENTION INDICES WITH RP-HPLC USING ACETONITRILE/WATER SYSTEM

    Directory of Open Access Journals (Sweden)

    Rinaldi Idroes

    2010-06-01

    Full Text Available Some factors such as the changes of the stationary phase, temperature, pH-value, mobile-phase composition and flow rate play a crucial role in effecting the sensitivity of retention times in high performance liquid chromatography (HPLC system. Utilizing a retention index system is one of the methods to minimize those effects. Besides the mentioned factors, dead-time influences on determining the retention index as well. In comparison with Gas Chromatography (GC, the retention Index determination method in HPLC is still widely discussed, due to the difficulty of utilizing n-alkane as standard. In addition, the solutes in HPLC interact with the mobile-phase, thus the retention behavior also depend on the mobile-phase. Actually, It is difficult to use n-alkanes in HPLC as standards in case of some considerable problems, due to they are very non polar but also large retention times which lack of chromophores. Therefore, using n-alkane in routine analysis could be inconvenient. In comparison with n-alkanes, the alkylarylketones homologous series are stable compounds, commercially available and easily detected by a UV detector. This paper introduces Determination of Kovats Retention Index in the HPLC using Alkylarylketone homologous series and then is connected with n-alkane as a frame of reference. Steroids were used as test substance for calculating Kovats retention index values in acetonitrile/water system.   Keywords: Kovats Retention Index, RP- HPLC, n-alkane, alkylarylketone

  19. Comparative evaluation of an ISO 3632 method and an HPLC-DAD method for safranal quantity determination in saffron.

    Science.gov (United States)

    García-Rodríguez, M Valle; López-Córcoles, Horacio; Alonso, Gonzalo L; Pappas, Christos S; Polissiou, Moschos G; Tarantilis, Petros A

    2017-04-15

    The aim of this work was a comparison of the ISO 3632 (2011) method and an HPLC-DAD method for safranal quantity determination in saffron. Samples from different origins were analysed by UV-vis according to ISO 3632 (2011) and by HPLC-DAD. Both methods were compared, and there was no correlation between the safranal content obtained by UV-vis and HPLC-DAD. An over-estimation in the UV-vis experiment was observed, which was related to the cis-crocetin esters content, as well as other compounds. The results demonstrated that there was no relationship between ISO quality categories and safranal content using HPLC-DAD. Therefore, HPLC-DAD might be preferable to UV-vis for determining the safranal content and the classification of saffron for commercial purposes. In addition, HPLC-DAD was adequate for determining the three foremost parameters that define the quality of saffron (crocetin esters, picrocrocin and safranal); therefore, this approach could be included in the ISO 3632 method (2011). Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Stability of an anti-stroke peptide: driving forces and kinetics in chemical degradation.

    Science.gov (United States)

    Li, Rui; Wang, Fengzhen; Chen, Li; Zhu, Shuning; Wu, Lin; Jiang, Sunmin; Xu, Qunwei; Zhu, Dongya

    2014-09-10

    NR2B9c (Lys-Leu-Ser-Ser-Ile-Glu-Ser-Asp-Val) is a 9-amino acid peptide that has been illustrated to be a potential anti-stroke drug. For more effective treatment, suitable drug delivery systems should be developed. However, little is known about the stability of NR2B9c which is essential to its formulation. In this study, a reversed-phase high-performance liquid chromatography (HPLC) was applied to study the forced degradation behavior and stability of NR2B9c. HPLC studies were performed with an C8 column using a mobile phase consisting of acetonitrile (14.5:85.5, v/v) and aqueous solution (0.1% trifluoroacetic acid (TFA) and 0.05 M KH2PO4). The flow rate and the wavelength set during HPLC detection were 1.0 mL/min and 205 nm, respectively. The degradation pattern of NR2B9c aqueous solution followed pseudo first-order kinetics. The degradation rate at pH 7.5 was the slowest according to the plotting V-shaped pH-rate profile. The influence of temperature on the rate of reactions was interpreted in terms of Arrhenius equation (r(2)>0.98). Thermodynamic parameters were calculated based on Eyring equation (r(2)>0.98). The concentrations of drug, buffer species, buffer concentrations, oxidation and organic solvents have noticeable effects on the degradation of NR2B9c while ultrasound shows little impact under the experimental conditions. In a word, this study may give a detailed description of stability of NR2B9c. Copyright © 2014. Published by Elsevier B.V.

  1. High-Resolution Inhibition Profiling Combined with HPLC-HRMS-SPE-NMR for Identification of PTP1B Inhibitors from Vietnamese Plants

    Directory of Open Access Journals (Sweden)

    Binh Thi Dieu Trinh

    2017-07-01

    Full Text Available Protein tyrosine phosphatase 1B (PTP1B plays a key role as a negative regulator in insulin signal transduction by deactivating the insulin receptor. Thus, PTP1B inhibition has emerged as a potential therapeutic strategy for curing insulin resistance. In this study, 40 extracts from 18 different plant species were investigated for PTP1B inhibitory activity in vitro. The most promising one, the EtOAc extract of Ficus racemosa, was investigated by high-resolution PTP1B inhibition profiling combined with HPLC-HRMS-SPE-NMR analysis. This led to the identification of isoderrone (1, derrone (2, alpinumisoflavone (3 and mucusisoflavone B (4 as PTP1B inhibitors. IC50 of these compounds were 22.7 ± 1.7, 12.6 ± 1.6, 21.2 ± 3.8 and 2.5 ± 0.2 µM, respectively. Kinetics analysis revealed that these compounds inhibited PTP1B non-competitively with Ki values of 21.3 ± 2.8, 7.9 ± 1.9, 14.3 ± 2.0, and 3.0 ± 0.5 µM, respectively. These findings support the important role of F. racemosa as a novel source of new drugs and/or as a herbal remedy for treatment of type 2 diabetes.

  2. Simultaneous kinetic spectrometric determination of three flavonoid antioxidants in fruit with the aid of chemometrics

    Science.gov (United States)

    Sun, Ruiling; Wang, Yong; Ni, Yongnian; Kokot, Serge

    2014-03-01

    A simple, inexpensive and sensitive kinetic spectrophotometric method was developed for the simultaneous determination of three anti-carcinogenic flavonoids: catechin, quercetin and naringenin, in fruit samples. A yellow chelate product was produced in the presence neocuproine and Cu(I) - a reduction product of the reaction between the flavonoids with Cu(II), and this enabled the quantitative measurements with UV-vis spectrophotometry. The overlapping spectra obtained, were resolved with chemometrics calibration models, and the best performing method was the fast independent component analysis (fast-ICA/PCR (Principal component regression)); the limits of detection were 0.075, 0.057 and 0.063 mg L-1 for catechin, quercetin and naringenin, respectively. The novel method was found to outperform significantly the common HPLC procedure.

  3. Reaction networks and kinetics of biochemical systems.

    Science.gov (United States)

    Arceo, Carlene Perpetua P; Jose, Editha C; Lao, Angelyn R; Mendoza, Eduardo R

    2017-01-01

    This paper further develops the connection between Chemical Reaction Network Theory (CRNT) and Biochemical Systems Theory (BST) that we recently introduced [1]. We first use algebraic properties of kinetic sets to study the set of complex factorizable kinetics CFK(N) on a CRN, which shares many characteristics with its subset of mass action kinetics. In particular, we extend the Theorem of Feinberg-Horn [9] on the coincidence of the kinetic and stoichiometric subsets of a mass action system to CF kinetics, using the concept of span surjectivity. We also introduce the branching type of a network, which determines the availability of kinetics on it and allows us to characterize the networks for which all kinetics are complex factorizable: A "Kinetics Landscape" provides an overview of kinetics sets, their algebraic properties and containment relationships. We then apply our results and those (of other CRNT researchers) reviewed in [1] to fifteen BST models of complex biological systems and discover novel network and kinetic properties that so far have not been widely studied in CRNT. In our view, these findings show an important benefit of connecting CRNT and BST modeling efforts. Copyright © 2016 Elsevier Inc. All rights reserved.

  4. Kinetics of heterogeneous catalytic reactions

    CERN Document Server

    Boudart, Michel

    2014-01-01

    This book is a critical account of the principles of the kinetics of heterogeneous catalytic reactions in the light of recent developments in surface science and catalysis science. Originally published in 1984. The Princeton Legacy Library uses the latest print-on-demand technology to again make available previously out-of-print books from the distinguished backlist of Princeton University Press. These paperback editions preserve the original texts of these important books while presenting them in durable paperback editions. The goal of the Princeton Legacy Library is to vastly increase acc

  5. CMD kinetics and regenerative medicine.

    Science.gov (United States)

    Anjamrooz, Seyed Hadi

    2016-01-01

    The author's theory of the cell memory disc (CMD) offers a radical and holistic picture of the cell from both functional and structural perspectives. Despite all of the attention that has been focused on different regenerative strategies, several serious CMD-based obstacles still remain that make current cell therapies inherently unethical, harmful, and largely ineffective from a clinical viewpoint. Accordingly, unless there is a real breakthrough in finding an alternative or complementary approach to overcome these barriers, all of the discussion regarding cell-based therapies may be fruitless. Hence, this paper focuses on the issue of CMD kinetics in an attempt to provide a fresh perspective on regenerative medicine.

  6. Kinetic Modeling of Microbiological Processes

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Chongxuan [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Fang, Yilin [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2012-08-26

    Kinetic description of microbiological processes is vital for the design and control of microbe-based biotechnologies such as waste water treatment, petroleum oil recovery, and contaminant attenuation and remediation. Various models have been proposed to describe microbiological processes. This editorial article discusses the advantages and limiation of these modeling approaches in cluding tranditional, Monod-type models and derivatives, and recently developed constraint-based approaches. The article also offers the future direction of modeling researches that best suit for petroleum and environmental biotechnologies.

  7. Identification of chemical markers in Cordyceps sinensis by HPLC-MS/MS.

    Science.gov (United States)

    Hu, Hankun; Xiao, Ling; Zheng, Baogen; Wei, Xin; Ellis, Alexis; Liu, Yi-Ming

    2015-10-01

    Authentication and quality assessment of Cordyceps sinensis, a precious and pricey natural product that offers a variety of health benefits, is highly significant. To identify effective chemical markers, authentic C. sinensis was thoroughly screened by using HPLC-MS/MS. In addition to many previously reported ingredients, two glycosides, i.e., cyclo-Ala-Leu-rhamnose and Phe-o-glucose, were detected for the first time in this material. Six ingredients detected, including cordycepin, D-mannitol, Phe, Phe-o-glucose, cyclo-Gly-Pro, and cyclo-Ala-Leu-rhamnose, were selected as a collection of chemical markers. An HPLC-MS/MS method was developed to simultaneously quantify them with sensitivity and specificity. The method had limits of detection ranging from 0.008 μg mL(-1) for cordycepin to 0.75 μg mL(-1) for cyclo-Gly-Pro. Recovery was found between 96 and 103 % in all tests. To evaluate the effectiveness of the marker collection proposed, five authentic C. sinensis samples and five samples of its substitutes were analyzed. Cordycepin, D-mannitol, and Phe were found present in all samples. The contents ranged from 0.0076 to 0.029 % (w/w) for cordycepin, 0.33 to 18.9 % for mannitol, and 0.0013 to 0.642 % for Phe. Interestingly, the two glycosides, Phe-o-glucose and cyclo-Ala-Leu-rhamnose, were detected only in authentic C. sinensis samples. These results indicated that the proposed protocol based on HPLC-MS/MS quantification of the markers might have a great potential in authentication and quality assessment of C. sinensis. Graphical abstract Chemical markers of C. sinensis identified in this work.

  8. The Second SeaWiFS HPLC Analysis Round-Robin Experiment (SeaHARRE-2)

    Science.gov (United States)

    2005-01-01

    Eight international laboratories specializing in the determination of marine pigment concentrations using high performance liquid chromatography (HPLC) were intercompared using in situ samples and a variety of laboratory standards. The field samples were collected primarily from eutrophic waters, although mesotrophic waters were also sampled to create a dynamic range in chlorophyll concentration spanning approximately two orders of magnitude (0.3 25.8 mg m-3). The intercomparisons were used to establish the following: a) the uncertainties in quantitating individual pigments and higher-order variables (sums, ratios, and indices); b) an evaluation of spectrophotometric versus HPLC uncertainties in the determination of total chlorophyll a; and c) the reduction in uncertainties as a result of applying quality assurance (QA) procedures associated with extraction, separation, injection, degradation, detection, calibration, and reporting (particularly limits of detection and quantitation). In addition, the remote sensing requirements for the in situ determination of total chlorophyll a were investigated to determine whether or not the average uncertainty for this measurement is being satisfied. The culmination of the activity was a validation of the round-robin methodology plus the development of the requirements for validating an individual HPLC method. The validation process includes the measurements required to initially demonstrate a pigment is validated, and the measurements that must be made during sample analysis to confirm a method remains validated. The so-called performance-based metrics developed here describe a set of thresholds for a variety of easily-measured parameters with a corresponding set of performance categories. The aggregate set of performance parameters and categories establish a) the overall performance capability of the method, and b) whether or not the capability is consistent with the required accuracy objectives.

  9. Evaporative light scattering detection in quantitative HPLC of PAC mixtures and coal-tar pitches

    Energy Technology Data Exchange (ETDEWEB)

    Cebolla, V.L.; Membrado, L.; Vela, J. [Instituto de Carboquimica, Zaragoza (Spain)] [and others

    1996-12-31

    The term Polycyclic Aromatic Compounds (PACs) include a wide variety of classes of compounds. In turn, the number of possible PACs for each class is of astronomical proportion. Environmental and fossil-fuel samples are composed of very complex mixtures of unknown PACs. The strategy for their analysis depends, among others, on the nature of matrix and PAC concentration, and involves cleanup/prefractionation steps and HPLC analysis. Therefore, HPLC detectors must be calibrated with pure reference standards for every substance to be quantified. However, only a relatively small fraction of PACs can unambiguously be identified and are commercially available. An ideal detector for chromatography of complex mixtures should provide uniform response factors for each separated compound or class of compounds. None of the conventional HPLC detectors (UV, Refractive Index, fluorescence) meet this requirement, neither for mixtures of unknown but well-separated pure peaks nor for compound-class fractionation of fossil fuels (where other additional problems can occur, such as presence of very heavy and polar PACs, quenching problems using fluorescence detection, need of tedious absolute calibrations, etc.) It has been reported that the Evaporative Light Scattering Detector (ELSD) enables all types of non-volatile solutes to be detected, although it has recently been reported that solutes having a lower volatility than the mobile phase can be analyzed working at mild temperatures. Detector response has been reported to be quite independent of the chemical composition of the solute. However, very different response factors were reported in the past in the case of semi-volatile PACs. This work intends: (i) to evaluate the possibility of the application of ELSD in order to quantify PACs in complex mixtures, (ii) to theoretically justify the responses of the studied PACs, and (iii) to lay the groundwork for application to fossil-fuel characterization.

  10. A lectin HPLC method to enrich selectively-glycosylated peptides from complex biological samples.

    Science.gov (United States)

    Johansen, Eric; Schilling, Birgit; Lerch, Michael; Niles, Richard K; Liu, Haichuan; Li, Bensheng; Allen, Simon; Hall, Steven C; Witkowska, H Ewa; Regnier, Fred E; Gibson, Bradford W; Fisher, Susan J; Drake, Penelope M

    2009-10-01

    Glycans are an important class of post-translational modifications. Typically found on secreted and extracellular molecules, glycan structures signal the internal status of the cell. Glycans on tumor cells tend to have abundant sialic acid and fucose moieties. We propose that these cancer-associated glycan variants be exploited for biomarker development aimed at diagnosing early-stage disease. Accordingly, we developed a mass spectrometry-based workflow that incorporates chromatography on affinity matrices formed from lectins, proteins that bind specific glycan structures. The lectins Sambucus nigra (SNA) and Aleuria aurantia (AAL), which bind sialic acid and fucose, respectively, were covalently coupled to POROS beads (Applied Biosystems) and packed into PEEK columns for high pressure liquid chromatography (HPLC). Briefly, plasma was depleted of the fourteen most abundant proteins using a multiple affinity removal system (MARS-14; Agilent). Depleted plasma was trypsin-digested and separated into flow-through and bound fractions by SNA or AAL HPLC. The fractions were treated with PNGaseF to remove N-linked glycans, and analyzed by LC-MS/MS on a QStar Elite. Data were analyzed using Mascot software. The experimental design included positive controls-fucosylated and sialylated human lactoferrin glycopeptides-and negative controls-high mannose glycopeptides from Saccharomyces cerevisiae-that were used to monitor the specificity of lectin capture. Key features of this workflow include the reproducibility derived from the HPLC format, the positive identification of the captured and PNGaseF-treated glycopeptides from their deamidated Asn-Xxx-Ser/Thr motifs, and quality assessment using glycoprotein standards. Protocol optimization also included determining the appropriate ratio of starting material to column capacity, identifying the most efficient capture and elution buffers, and monitoring the PNGaseF-treatment to ensure full deglycosylation. Future directions include

  11. [Study and comparison on HPLC fingerprints of flavonoids of frequently used Chinese materia medica in citrus].

    Science.gov (United States)

    Chen, Yonggang; Lin, Li

    2011-10-01

    To establish the HPLC fingerprint of flavonoids of the six clinical frequently used Chinese materia medica for regulating Qi flow,such as Citri grandis, C. grands, Citri Reticulatae Pericarpium, Citri Reticulatae Pericarpium Viride, Aurantii Fructus, and Aurantii Fructus Immaturus from Citrus, and analysis differences in the fingerprints to provide scientific basis for profile-effect research and clinical reasonable use. HPLC was performed on a C18 column with methanol-water (with acetic acid), to establish HPLC fingerprints of the six kinds of medicinal herbs on the same chromatograph condition. The six frequently used Chinese materia medica were divided into naringin type and hesperidin type according to the method of phytochemotaxonomy. Based on the retention time of chromatograph peaks, C. grandis and C. grands had fifteen common peaks; Citri Reticulatae Pericarpium, Citri Reticulatae Pericarpium Viride, Aurantii Fructus and Aurantii Fructus Immaturus had ten common peaks. All herbs had five common peaks. Compared with mutual model, the holistic similarity of chromatograms of C. grandis and C. grands was in the range of 0.9285 - 0.9962. The degree of similarity was high. For Citri Reticulatae Pericarpium, Citri Reticulatae Pericarpium Viride and Aurantii Fructus Immaturus, it was in the range of 0.9221 - 0.9973 and high. But the similarity of Aurantii Fructus was only in 0.4547 - 0.7733 with the mutual model. The established fingerprints of flavonoids of the six common traditional Chinese medicines can be used to compare the differences intuitively. Meanwhile, the peak height and peak areas of characteristic peaks are different remarkably, but whether it is connected with the different function of regulating Qi flow of the six medical materials in clinical use, is still needed to be studied.

  12. Selenosugar determination in porcine liver using multidimensional HPLC with atomic and molecular mass spectrometry.

    Science.gov (United States)

    Lu, Ying; Pergantis, Spiros A

    2009-01-01

    A methodology based on liquid chromatography coupled online with atomic and molecular mass spectrometry was developed for identifying trace amounts of the selenosugar methyl 2-acetamido-2-deoxy-1-seleno-β-D-galactopyranoside (SeGalNAc) in porcine liver, obtained from an animal that had not received selenium supplementation. Sample preparation was especially critical for the identification of SeGalNAc by molecular mass spectrometry. This involved liver extraction using a Tris buffer, followed by sequential centrifugations. The resulting cytosolic fraction was pre-concentrated and the low molecular weight selenium (LMWSe) fraction obtained from a size exclusion column was collected, concentrated, and subsequently analyzed using a tandem dual-column HPLC-ICP-MS system which consisted of strong cation exchange (SCX) and reversed phase (RP) columns coupled in tandem. Hepatocytosolic SeGalNAc was tentatively identified by retention time matching and spiking. Its identity was further confirmed by using the same type of chromatography on-line with atmospheric pressure chemical ionization tandem mass spectrometry operated in the selected reaction monitoring (SRM) mode. Four SRM transitions, characteristic of SeGalNAc, were monitored and their intensity ratios determined in order to confirm SeGalNAc identification. Instrument limits of detection for SeGalNAc by SCX-RP HPLC-ICP-MS and SCX-RP HPLC-APCI-MS/MS were 3.4 and 2.9 μg Se L(-1), respectively. Selenium mass balance analysis revealed that trace amounts of SeGalNAc, 2.16±0.94 μg Se kg(-1) liver (wet weight) were present in the liver cytosol, corresponding to 0.4% of the total Se content in the porcine liver.

  13. HPLC-DAD determination of CNS-acting drugs in human blood, plasma, and serum.

    Science.gov (United States)

    Moreno, Ana María Jiménez; Navas, María José; Asuero, Agustín G

    2014-01-01

    This is a review of the literature regarding high-performance liquid chromatography-diode array detection (HPLC-DAD) procedures for the detection and determination of several categories of central nervous system-acting drugs in blood, plasma, or serum samples. Psychiatric and neurological drugs, such as antidepressants, benzodiazepines, antipsychotics, antiepileptics, and antiparkinsonians, have been included because of their relevance to therapeutic drug monitoring and systematic toxicological analysis. Articles published between 2000 and January 2012 have been taken into consideration. This review has focused on methodological approaches, sample pretreatment techniques, and other practical aspects.

  14. Design and Prototype of an Automated Column-Switching HPLC System for Radiometabolite Analysis

    Directory of Open Access Journals (Sweden)

    Neil Vasdev

    2016-08-01

    Full Text Available Column-switching high performance liquid chromatography (HPLC is extensively used for the critical analysis of radiolabeled ligands and their metabolites in plasma. However, the lack of streamlined apparatus and consequently varying protocols remain as a challenge among positron emission tomography laboratories. We report here the prototype apparatus and implementation of a fully automated and simplified column-switching procedure to allow for the easy and automated determination of radioligands and their metabolites in up to 5 mL of plasma. The system has been used with conventional UV and coincidence radiation detectors, as well as with a single quadrupole mass spectrometer.

  15. Development and Validation of New RP-HPLC Method for the Determination of Dexrazoxane

    OpenAIRE

    Basaveswara Rao, M. V.; Prasanthi, V.; Rao, G. Venkata; Raman, B. V.

    2012-01-01

    A new sensitive, precise, rapid and linear RP-HPLC method was developed and validated for the determination of dexrazoxane in formulations and human serum samples. Good chromatographic separation of dexrazoxane was achieved by using Kromasil C18 column. The system was operated at ambient temperature using a mobile phase consisting of methanol, 5% ortho phosphoric acid, 0.01M ammonium dihydrogen phosphate and tetrahydrofuran, pH 4.2 (10:40:30:20, v/v) isocratically at a flow rate of 1 ml/min. ...

  16. 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...

  17. HPLC/UV quantitation of retinal, retinol, and retinyl esters in serum and tissues

    OpenAIRE

    Kane, Maureen A.; Folias, Alexandra E.; Napoli, Joseph L.

    2008-01-01

    We report robust HPLC/UV methods for quantifying retinyl esters (RE), retinol (ROL) and retinal (RAL) applicable to diverse biological samples, with lower limits of detection of 0.7 pmol, 0.2 pmol, and 0.2 pmol, respectively, and linear ranges >3 orders of magnitude. These assays function well with small, complex biological samples (10–20 mg tissue). Coefficients of variation range from: intra-day, 5.9–10.0%; inter-day, 5.9–11.0%. Quantification of endogenous RE, ROL, and RAL in mouse serum a...

  18. [Determination of contents of amygdalin in traditional and granular decoctions of Maxingshigan decoction by HPLC].

    Science.gov (United States)

    Wu, Kong-yun; Liang, Guang-yi; He, Zhu-ying; Jin, Feng-yun; Li, Xing; Feng, Hua

    2007-09-01

    To determine the contents of amygdalin in traditional and granular decoctions of Maxingshigan decoction. The determination was carried out by HPLC with an ODS column and a mobile phase of water-methanol (23:77) at 215 nm. The content of amygdalin in traditional decoction of Maxingshigan Decoction was 17.74 mg/g and 24.80 mg/g in granular one. The content of glycyrrhizic acid in traditional decoction of Maxingshigan decoction is obviously higher than that in granular one.

  19. Design and Prototype of an Automated Column-Switching HPLC System for Radiometabolite Analysis.

    Science.gov (United States)

    Vasdev, Neil; Collier, Thomas Lee

    2016-08-17

    Column-switching high performance liquid chromatography (HPLC) is extensively used for the critical analysis of radiolabeled ligands and their metabolites in plasma. However, the lack of streamlined apparatus and consequently varying protocols remain as a challenge among positron emission tomography laboratories. We report here the prototype apparatus and implementation of a fully automated and simplified column-switching procedure to allow for the easy and automated determination of radioligands and their metabolites in up to 5 mL of plasma. The system has been used with conventional UV and coincidence radiation detectors, as well as with a single quadrupole mass spectrometer.

  20. De HPLC analyse van bromacil, diuron en metaboliet 3,4-dichlooraniline in bronwater

    OpenAIRE

    Goewie CE; Hogendoorn EA

    1987-01-01

    In het kader van het ad-hoc inspectie onderzoek zijn in de maand maart 1987 in totaal drie watermonsters geanalyseerd op aanwezigheid van diuron. Gelijktijdig zijn door de afdeling BM van het LOC de monsters met een GLC-methode geanalyseerd op aanwezigheid van residuen bromacil en methalaxil. Voor de analyse van diuron is een HPLC-methode ontwikkeld, waarbij de component in bronwater geanalyseerd kan worden tot een aantoonbaarheidsgrens van 0,01 mug/l (ppb). Met de methode kunnen eveneens de ...

  1. Tannin analysis of chestnut bark samples (Castanea sativa Mill.) by HPLC-DAD-MS.

    Science.gov (United States)

    Comandini, Patrizia; Lerma-García, María Jesús; Simó-Alfonso, Ernesto Francisco; Toschi, Tullia Gallina

    2014-08-15

    In the present investigation, an HPLC-DAD/ESI-MS method for the complete analysis of tannins and other phenolic compounds of different commercial chestnut bark samples was developed. A total of seven compounds (vescalin, castalin, gallic acid, vescalagin, 1-O-galloyl castalagin, castalagin and ellagic acid) were separated and quantified, being 1-O-galloyl castalagin tentatively identified and found for the first time in chestnut bark samples. Thus, this method provided information regarding the composition and quality of chestnut bark samples, which is required since these samples are commercialised due to their biochemical properties as ingredients of food supplements. Copyright © 2014 Elsevier Ltd. All rights reserved.

  2. HPLC fucoxanthin profiles of a microalga, a macroalga and a pure fucoxanthin standard

    Directory of Open Access Journals (Sweden)

    Su Chern Foo

    2017-02-01

    Full Text Available Data in this article illustrate representative fucoxanthin chromatograms of a microalga, Chaetoceros calcitrans; a macroalga, Saccharina japonica and; a pure fucoxanthin standard. High performance liquid chromatography (HPLC eluted fucoxanthin at the 7.008±0.024th min. This data article refers to the research article ‘‘Antioxidant capacities of fucoxanthin-producing algae as influenced by their carotenoid and phenolic contents’’ Foo et al. [1]; where a more comprehensive data interpretation and analysis is explained.

  3. Determination of Arctiin and Arctigenin Contents in Arctium Tomentosum Mill. by HPLC Method

    OpenAIRE

    Xiaoying Zhou; Haoke Zhang; Liang Ge; Haiyan Gong; Shuge Tian

    2011-01-01

    A simple, precise, rapid and accurate, binary-phase high performance liquid chromatographic method has been developed for the determination of arctiin and arctigenin contents in the Arctium tomentosumMill. with short run time. Chromatographic separation was achieved by using HPLC system, consisting of a Shimadzu LC-6AD and Kromasil C18 column (250×4.6 mm, 5 μm, with pre-column), the mobile phase consists of methanol and water (55: 45). Detection wavelength was 280 nm. The speed of flow was 1....

  4. Time-resolved SAXS measurements facilitated by online HPLC buffer exchange

    DEFF Research Database (Denmark)

    Jensen, Malene Hillerup; Toft, Katrine Nørgaard; David, Gabriel

    2010-01-01

    be possible to separate contributions from individual species present in solution. Hence, time-resolved SAXS (TR-SAXS) data of processes in development can be analyzed. Many reported TR-SAXS results are initialized by a sudden change in buffer conditions facilitated by rapid mixing combined with either...... continuous or stopped flow. In this paper a method for obtaining TR-SAXS data from systems where the reaction is triggered by removal of a species is presented. This method is based on fast buffer exchange over a short desalting column facilitated by an online HPLC (high-performance liquid chromatography...

  5. Kinetic Chain Rehabilitation: A Theoretical Framework

    Directory of Open Access Journals (Sweden)

    Aaron Sciascia

    2012-01-01

    Full Text Available Sequenced physiologic muscle activations in the upper and lower extremity result in an integrated biomechanical task. This sequencing is known as the kinetic chain, and, in upper extremity dominant tasks, the energy development and output follows a proximal to distal sequencing. Impairment of one or more kinetic chain links can create dysfunctional biomechanical output leading to pain and/or injury. When deficits exist in the preceding links, they can negatively affect the shoulder. Rehabilitation of shoulder injuries should involve evaluation for and restoration of all kinetic chain deficits that may hinder kinetic chain function. Rehabilitation programs focused on eliminating kinetic chain deficits, and soreness should follow a proximal to distal rationale where lower extremity impairments are addressed in addition to the upper extremity impairments. A logical progression focusing on flexibility, strength, proprioception, and endurance with kinetic chain influence is recommended.

  6. Aflatoxins contamination in Pakistani brown rice: a comparison of TLC, HPLC, LC-MS/MS and ELISA techniques.

    Science.gov (United States)

    Iqbal, Javed; Asghar, Muhammad Asif; Ahmed, Aftab; Khan, Mobeen Ahmed; Jamil, Khalid

    2014-12-01

    Advancement in the field of analytical food-chemistry has explored various experimental techniques for aflatoxins (AFs) quantification. The present study was aimed to compare four different techniques; thin-layer chromatography (TLC), high-performance liquid chromatography (HPLC), liquid chromatography-tandem mass spectrometry (LC-MS/MS) and enzyme-linked immunosorbent assay (ELISA) for the analysis of aflatoxin B₁ (AFB₁), B₂ (AFB₂), G₁ (AFG₁) and G₂ (AFG₂) in brown rice (n = 120) being collected from Karachi, Pakistan. All the four assays provide precised, accurate and comparable results. However, some differences were observed. For instance, TLC, HPLC and LC-MS/MS methodologies offered the advantage of the quantification of individual toxins in contrast to ELISA technique. The contamination ranges of AFB₁/AFB₂ as determined by TLC, HPLC and LC-MS/MS were 1.18-9.97/0.59-1.52, 0.16-10.54/0.26-1.35 and 0.11-10.88/0.38-1.48 µg/kg, respectively. However, AFG₁ and AFG₂ were not detected in any tested samples. Furthermore, owing to low-detection limit and sensitivity, HPLC and LC-MS/MS methodologies have identified greater number of contaminated samples in comparison to TLC and ELISA techniques. The overall average results of total AFs as provided by HPLC (3.79 µg/kg) and LC-MS/MS (3.89 µg/kg) were found higher in comparison to TLC (3.68 µg/kg) and ELISA (3.70 µg/kg). On the basis of achieved results, it was concluded that TLC, HPLC, LC-MS/MS and ELISA techniques are valuable tool for the quantification of AFs in cereals and grains. Furthermore, HPLC and LC-MS/MS techniques offer an added advantage for the detection of AFs in diminutive levels.

  7. Combustion kinetics and reaction pathways

    Energy Technology Data Exchange (ETDEWEB)

    Klemm, R.B.; Sutherland, J.W. [Brookhaven National Laboratory, Upton, NY (United States)

    1993-12-01

    This project is focused on the fundamental chemistry of combustion. The overall objectives are to determine rate constants for elementary reactions and to elucidate the pathways of multichannel reactions. A multitechnique approach that features three independent experiments provides unique capabilities in performing reliable kinetic measurements over an exceptionally wide range in temperature, 300 to 2500 K. Recent kinetic work has focused on experimental studies and theoretical calculations of the methane dissociation system (CH{sub 4} + Ar {yields} CH{sub 3} + H + Ar and H + CH{sub 4} {yields} CH{sub 3} + H{sub 2}). Additionally, a discharge flow-photoionization mass spectrometer (DF-PIMS) experiment is used to determine branching fractions for multichannel reactions and to measure ionization thresholds of free radicals. Thus, these photoionization experiments generate data that are relevant to both reaction pathways studies (reaction dynamics) and fundamental thermochemical research. Two distinct advantages of performing PIMS with high intensity, tunable vacuum ultraviolet light at the National Synchrotron Light Source are high detection sensitivity and exceptional selectivity in monitoring radical species.

  8. Preventing Corrosion by Controlling Cathodic Reaction Kinetics

    Science.gov (United States)

    2016-03-25

    Preventing corrosion by controlling cathodic reaction kinetics Progress Report for Period: 1 SEP 2015-31 MAR 2016 John Keith Department of...25 March 2016 Preventing corrosion by controlling cathodic reaction kinetics Annual Summary Report: FY16 PI: John Keith, 412-624-7016,jakeith...elements on the kinetics of oxygen reduction reaction catalyzed on titanium oxide in order to develop new approaches for controlling galvanic corrosion

  9. An Efficient Method for the Preparative Isolation and Purification of Flavonoid Glycosides and Caffeoylquinic Acid Derivatives from Leaves of Lonicera japonica Thunb. Using High Speed Counter-Current Chromatography (HSCCC) and Prep-HPLC Guided by DPPH-HPLC Experiments.

    Science.gov (United States)

    Wang, Daijie; Du, Ning; Wen, Lei; Zhu, Heng; Liu, Feng; Wang, Xiao; Du, Jinhua; Li, Shengbo

    2017-02-02

    In this work, the n-butanol extract from leaves of Lonicera japonica Thunb. (L. japonica) was reacted with DPPH and subjected to a HPLC analysis for the guided screening antioxidants (DPPH-HPLC experiments). Then, nine antioxidants, including flavonoid glycosides and caffeoylquinic acid derivatives, were isolated and purified from leaves of L. japonica using high speed counter-current chromatography (HSCCC) and prep-HPLC. The n-butanol extract was firstly isolated by HSCCC using methyl tert-butyl ether/n-butanol/acetonitrile/water (0.5% acetic acid) (2:2:1:5, v/v), yielding five fractions F1, F2 (rhoifolin), F3 (luteoloside), F4 and F5 (collected from the column after the separation). The sub-fractions F1, F4 and F5 were successfully separated by prep-HPLC. Finally, nine compounds, including chlorogenic acid (1), lonicerin (2), rutin (3), rhoifolin (4), luteoloside (5), 3,4-Odicaffeoylquinic acid (6), hyperoside (7), 3,5-O-dicaffeoylquinic acid (8), and 4,5-O-dicaffeoylquinic acid (9) were obtained, respectively, with the purities over 94% as determined by HPLC. The structures were identified by electrospray ionization mass spectrometry (ESI-MS), 1H- and 13C-NMR. Antioxidant activities were tested, and the isolated compounds showed strong antioxidant activities.

  10. An Efficient Method for the Preparative Isolation and Purification of Flavonoid Glycosides and Caffeoylquinic Acid Derivatives from Leaves of Lonicera japonica Thunb. Using High Speed Counter-Current Chromatography (HSCCC and Prep-HPLC Guided by DPPH-HPLC Experiments

    Directory of Open Access Journals (Sweden)

    Daijie Wang

    2017-02-01

    Full Text Available In this work, the n-butanol extract from leaves of Lonicera japonica Thunb. (L. japonica was reacted with DPPH and subjected to a HPLC analysis for the guided screening antioxidants (DPPH-HPLC experiments. Then, nine antioxidants, including flavonoid glycosides and caffeoylquinic acid derivatives, were isolated and purified from leaves of L. japonica using high speed counter-current chromatography (HSCCC and prep-HPLC. The n-butanol extract was firstly isolated by HSCCC using methyl tert-butyl ether/n-butanol/acetonitrile/water (0.5% acetic acid (2:2:1:5, v/v, yielding five fractions F1, F2 (rhoifolin, F3 (luteoloside, F4 and F5 (collected from the column after the separation. The sub-fractions F1, F4 and F5 were successfully separated by prep-HPLC. Finally, nine compounds, including chlorogenic acid (1, lonicerin (2, rutin (3, rhoifolin (4, luteoloside (5, 3,4-Odicaffeoylquinic acid (6, hyperoside (7, 3,5-O-dicaffeoylquinic acid (8, and 4,5-O-dicaffeoylquinic acid (9 were obtained, respectively, with the purities over 94% as determined by HPLC. The structures were identified by electrospray ionization mass spectrometry (ESI-MS, 1H- and 13C-NMR. Antioxidant activities were tested, and the isolated compounds showed strong antioxidant activities.

  11. MBS Analysis Of Kinetic Structures Using ADAMS

    DEFF Research Database (Denmark)

    Kirkegaard, Poul Henning; Nielsen, Søren R.K.

    2009-01-01

    -called multibody system (MBS) formalism. The present paper considers MBS modeling of kinetic architectural structures using the software packages ADAMS. As a result, it is found that symbolic MBS simulation tools facilitate a useful evaluation environment for MBS users during a design phase of responsive kinetic......The present paper considers multibody system (MBS) analysis of kinetic structures using the software package ADAMS. Deployable, foldable, expandable and reconfigurable kinetic structures can provide a change in the geometric morphology of the envelope by contributing to making it adaptable to e...

  12. Simultaneous column chromatographic extraction and purification of abscisic acid in peanut plants for direct HPLC analysis.

    Science.gov (United States)

    Zhang, Ya-Wen; Fan, Wei-Wei; Li, Hui; Ni, He; Han, Han-Bing; Li, Hai-Hang

    2015-10-01

    Abscisic acid (ABA), a universal signaling molecule, plays important roles in regulating plant growth, development and stress responses. The low contents and complex components in plants make it difficult to be accurately analyzed. A novel one-step sample preparation method for ABA in plants was developed. Fresh peanut (Arachis hypogaea) plant materials were fixed by oven-drying, microwave drying, boiling or Carnoy's fixative, and loaded onto a mini-preparing column. After washed the impurities, ABA was eluted with a small amount of solvent. ABA in plant materials was completely extracted and purified in 2mL solution and directly analyzed by HPLC, with a 99.3% recovery rate. Multiple samples can be simultaneously prepared. Analyses using this method indicated that the endogenous ABA in oven-dried peanut leaves increased 20.2-fold from 1.01 to 20.37μgg(-1) dry weight within 12h and then decreased in 30% polyethylene glycol 6000 treated plants, and increased 3.34-fold from 0.85 to 2.84μgg(-1) dry weight in 5 days and then decreased in soil drought treated plants. The method combined the column chromatographic extraction and solid-phase separation technologies in one step and can completely extracted plant endogenous ABA in a purified and highly concentrated form for direct HPLC analysis. Copyright © 2015 Elsevier B.V. All rights reserved.

  13. HPLC/PDA/ESI-MS evaluation of saffron (Crocus sativus L.) adulteration.

    Science.gov (United States)

    Sabatino, Leonardo; Scordino, Monica; Gargano, Maria; Belligno, Adalgisa; Traulo, Pasqualino; Gagliano, Giacomo

    2011-12-01

    The present study evaluated the reliability of the ISO/TS 3632-2 UV-Vis spectrometric method for saffron classification, making experiments on saffron samples to which were added increasing concentrations of common saffron spice adulterants (safflower, marigold and turmeric). The results showed that the ISO/TS 3632-2 method is not able to detect addition of up to 10-20%, w/w, of saffron adulterants. For additions from 20 to 50%, w/w, of the three adulterants, saffron was classified in a wrong category; addition of higher than 50%, w/w, determined variations in the investigated parameters that did not allow identification of the product as "saffron". In all cases, the method did not permit the recognition of the nature of the adulterant. On the contrary, the specificity of the HPLC/PDA/MS technique allowed the unequivocal identification of adulterant characteristic marker molecules that could be recognized by the values of absorbance and mass. The selection of characteristic ions of each marker molecule has revealed concentrations of up to 5%, w/w, for safflower and marigold and up to 2% for turmeric. In addition, the high dyeing power of turmeric allowed the determination of 2%, w/w, addition using exclusively the HPLC/PDA technique.

  14. Analysis of aldehydes in human exhaled breath condensates by in-tube SPME-HPLC.

    Science.gov (United States)

    Wang, ShuLing; Hu, Sheng; Xu, Hui

    2015-11-05

    In this paper, polypyrrole/graphene (PPy/G) composite coating was prepared by a facile electrochemical polymerization strategy on the inner surface of a stainless steel (SS) tube. Based on the coating tube, a novel online in-tube solid-phase microextraction -high performance liquid chromatography (IT-SPME-HPLC) was developed and applied for the extraction of aldehydes in the human exhaled breath condensates (EBC). The hybrid PPy/G nanocomposite exhibits remarkable chemical and mechanical stability, high selectivity, and satisfactory extraction performance toward aldehyde compounds. Moreover, the proposed online IT-SPME-HPLC method possesses numerous superiorities, such as time and cost saving, process simplicity, high precision and sensitivity. Some parameters related to extraction efficiency were optimized systematically. Under the optimal conditions, the recoveries of the aldehyde compounds at three spiked concentration levels varied in the range of 85%-117%. Good linearity was obtained with excellent correlation coefficients (R(2)) being larger than 0.994. The relative standard deviations (n = 5) of the method ranged from 1.8% to 11.3% and the limits of detection were between 2.3 and 3.3 nmol L(-1). The successful application of the proposed method in human EBC indicated that it is a promising approach for the determination of trace aldehyde metabolites in complex EBC samples. Copyright © 2015 Elsevier B.V. All rights reserved.

  15. HPLC method for measurement of human salivary α-amylase inhibition by aqueous plant extracts.

    Science.gov (United States)

    Takács, István; Takács, Ákos; Pósa, Anikó; Gyémánt, Gyöngyi

    2017-06-01

    Control of hyperglycemia is an important treatment in metabolic disorders such as type II diabetes and obesity. α-Amylase, as the first enzyme of glucose release from dietary polysaccharides, is a potential target to identify new sources of novel anti-obesity and anti-diabetic drugs. In this work, different herbal extracts as α-amylase inhibitors were studied by measuring the rate of the cleavage of a maltooligomer substrate 2-chloro-4-nitrophenyl-β-D-maltoheptoside. Measurement of chromophore containing products after reversed phase HPLC separation was used for α-amylase activity measurement. Rates of hydrolysis catalysed by human salivary α-amylase were determined in the presence and absence of lyophilised water extracts of eleven herbs. Remarkable bioactivities were found for extracts of Cinnamomum zeylanicum Blume (bark), Camellia sinensis L. (leaf), Ribes nigrum L. (leaf), Laurus nobilis L. (leaf), Vaccinium macrocarpon Aiton (fruit) and Syzygium aromaticum L. (bud). Determined IC50 values were in 0.017-41 μg/ml range for these six selected plant extracts. Our results confirm the applicability of this HPLC-based method for the quick and reliable comparison of plants as α-amylase inhibitors.

  16. HPLC fingerprint analysis combined with chemometrics for pattern recognition of ginger.

    Science.gov (United States)

    Feng, Xu; Kong, Weijun; Wei, Jianhe; Ou-Yang, Zhen; Yang, Meihua

    2014-03-01

    Ginger, the fresh rhizome of Zingiber officinale Rosc. (Zingiberaceae), has been used worldwide; however, for a long time, there has been no standard approbated internationally for its quality control. To establish an efficacious and combinational method and pattern recognition technique for quality control of ginger. A simple, accurate and reliable method based on high-performance liquid chromatography with photodiode array (HPLC-PDA) detection was developed for establishing the chemical fingerprints of 10 batches of ginger from different markets in China. The method was validated in terms of precision, reproducibility and stability; and the relative standard deviations were all less than 1.57%. On the basis of this method, the fingerprints of 10 batches of ginger samples were obtained, which showed 16 common peaks. Coupled with similarity evaluation software, the similarities between each fingerprint of the sample and the simulative mean chromatogram were in the range of 0.998-1.000. Then, the chemometric techniques, including similarity analysis, hierarchical clustering analysis and principal component analysis were applied to classify the ginger samples. Consistent results were obtained to show that ginger samples could be successfully classified into two groups. This study revealed that HPLC-PDA method was simple, sensitive and reliable for fingerprint analysis, and moreover, for pattern recognition and quality control of ginger.

  17. HPLC/QTOF-MS/MS application to investigate phenolic constituents from Ficus pandurata H. aerial roots.

    Science.gov (United States)

    Zhang, Xiaoping; Lv, Huiqing; Li, Zuguang; Jiang, Kezhi; Lee, Maw-Rong

    2015-06-01

    Ficus pandurata H. aerial roots are used as a traditional Chinese medicine for the treatment of uarthritis, indigestion and hyperuricemia. However, the bioactive constituents responsible for the pharmacological effects of F. pandurata H. are unclear. A simple and efficient HPLC/QTOF-MS/MS (high-performance liquid chromatography/electrospray ionization with quadrupole time-of-flight tandem mass spectrometry) method was established to detect and identify active constituents in the n-butanol extract of F. pandurata H. aerial roots. Chemical constituents were separated and investigated by HPLC/QTOF-MS/MS in the negative-ion mode. Thirty-seven compounds, including hydroxycinnamic acid derivatives, hydroxybenzoic acid derivatives, hydroquinone glycosides, flavonoid glycosides, etc., were identified or tentatively characterized in the n-butanol extract of F. pandurata H. aerial roots by comparing the UV spectra, accurate mass spectra and fragmentation pathways and retrieving the reference literatures. Moreover, the flavonoid trisaccharides and hydroxybenzoic acid derivatives were tentatively characterized in F. pandurata H. for the first time. The analytical tool used here is very valuable in the rapid separation and identification of the multiple and minor constituents in the n-butanol extract of F. pandurata H. aerial roots. Copyright © 2014 John Wiley & Sons, Ltd.

  18. A Simple HPLC-ELSD Method for Sugar Analysis in Goji Berry

    Directory of Open Access Journals (Sweden)

    D. Montesano

    2016-01-01

    Full Text Available Fructose, glucose, and sucrose were identified and quantified in commercial samples of Lycium barbarum L. fruits (goji berries by high performance liquid chromatography-evaporative light scattering detector (HPLC-ELSD method. This study described a rapid, simple, sensitive, selective, and reliable HPLC method suitable for the profiling of major sugars in berries, the evaluation of the nutritional/energetic properties, and assessment of the maturation stage. The proposed analytical method was validated and the results showed good precision, accuracy, and linearity. In all analyzed goji fruits, glucose and fructose were the predominant sugars, while sucrose content was about ten times lower than each monose. It was observed that glucose and fructose were detected in comparable quantities in all considered samples. Quantitative analysis showed that fructose, glucose, and sucrose content ranged from 154.20 to 259.13 mg g−1, from 152.92 to 284.60 mg g−1, and from 13.75 to 36.43 mg g−1, respectively.

  19. 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.

  20. Comparative authentication of Hypericum perforatum herbal products using DNA metabarcoding, TLC and HPLC-MS.

    Science.gov (United States)

    Raclariu, Ancuta Cristina; Paltinean, Ramona; Vlase, Laurian; Labarre, Aurélie; Manzanilla, Vincent; Ichim, Mihael Cristin; Crisan, Gianina; Brysting, Anne Krag; de Boer, Hugo

    2017-05-02

    Many herbal products have a long history of use, but there are increasing concerns over product efficacy, safety and quality in the wake of recent cases exposing discrepancies between labeling and constituents. When it comes to St. John's wort (Hypericum perforatum L.) herbal products, there is limited oversight, frequent off-label use and insufficient monitoring of adverse drug reactions. In this study, we use amplicon metabarcoding (AMB) to authenticate 78 H. perforatum herbal products and evaluate its ability to detect substitution compared to standard methods using thin-layer chromatography (TLC) and high performance liquid chromatography coupled with mass spectrometry (HPLC-MS). Hypericum perforatum was detected in 68% of the products using AMB. Furthermore, AMB detected incongruence between constituent species and those listed on the label in all products. Neither TLC nor HPLC-MS could be used to unambiguously identify H. perforatum. They are accurate methods for authenticating presence of the target compounds, but have limited efficiency in detecting infrageneric substitution and do not yield any information on other plant ingredients in the products. Random post-marketing AMB of herbal products by regulatory agencies could raise awareness among consumers of substitution and would provide an incentive to manufacturers to increase quality control from raw ingredients to commercialized products.

  1. Improved HPLC column-switching determination of Coenzyme Q and Vitamin E in plasma.

    Science.gov (United States)

    Bompadre, Stefano; Tulipani, Sara; Romandini, Stefania; Giorgetti, Raffaele; Battino, Maurizio

    2008-01-01

    A novel isocratic modified column-switching HPLC method for automated quantitative analysis of Vitamin E and Coenzyme Q, in the reduced and oxidized form, is described. Many column-switching HPLC methods are found in the literature, also for determining antioxidant substances, but we developed a different system of column-switching. An empty column, 5 cm long, was connected to the switching valve, before the sample loop and the extraction column. The sample loop was connected directly after the empty column. The inserted column, containing about 1.4 ml of the extraction eluent simulated a gradient elution, enhancing sensitivity and resolution. When switching the columns, the empty column is placed right before the extraction column and acts as a static mixer for the extraction phase and the incoming analytical phase. Samples were cleaned from interfering compounds by transfer onto a extraction-column, using a C-8 silica. Separation was performed onto an analytical column C18 3 m icrom, 150 mm x 4.6 mm at a flow rate of 1.0 ml/min with 20 mmol/l lithium perchlorate/perchloric acid, pH3.0 in Ethanol as analytical eluent. Detection was performed with a ESA Coulochem 5100 A model. The method was found to be suitable for automated analysis of Coenzyme Q, reduced and oxidized form, and Vitamin E in serum.

  2. Antioxidant, DNA protective efficacy and HPLC analysis of Annona muricata (soursop) extracts.

    Science.gov (United States)

    George, V Cijo; Kumar, D R Naveen; Suresh, P K; Kumar, R Ashok

    2015-04-01

    Annona muricata is a naturally occurring edible plant with wide array of therapeutic potentials. In India, it has a long history of traditional use in treating various ailments. The present investigation was carried out to characterize the phytochemicals present in the methanolic and aqueous leaf extracts of A. muricata, followed by validation of its radical scavenging and DNA protection activities. The extracts were also analyzed for its total phenolic contents and subjected to HPLC analysis to determine its active metabolites. The radical scavenging activities were premeditated by various complementary assays (DRSA, FRAP and HRSA). Further, its DNA protection efficacy against H2O2 induced toxicity was evaluated using pBR322 plasmid DNA. The results revealed that the extracts were highly rich in various phytochemicals including luteolin, homoorientin, tangeretin, quercetin, daidzein, epicatechin gallate, emodin and coumaric acid. Both the extracts showed significant (p < 0.05) radical scavenging activities, while methanolic extract demonstrated improved protection against H2O2-induced DNA damage when compared to aqueous extract. A strong positive correlation was observed for the estimated total phenolic contents and radical scavenging potentials of the extracts. Further HPLC analysis of the phyto-constituents of the extracts provides a sound scientific basis for compound isolation.

  3. Large-scale simulation of flow and transport in reconstructed HPLC-microchip packings.

    Science.gov (United States)

    Khirevich, Siarhei; Höltzel, Alexandra; Ehlert, Steffen; Seidel-Morgenstern, Andreas; Tallarek, Ulrich

    2009-06-15

    Flow and transport in a particle-packed microchip separation channel were investigated with quantitative numerical analysis methods, comprising the generation of confined, polydisperse sphere packings by a modified Jodrey-Tory algorithm, 3D velocity field calculations by the lattice-Boltzmann method, and modeling of convective-diffusive mass transport with a random-walk particle-tracking approach. For the simulations, the exact conduit cross section, the particle-size distribution of the packing material, and the respective average interparticle porosity (packing density) of the HPLC-microchip packings was reconstructed. Large-scale simulation of flow and transport at Peclet numbers of up to Pe = 140 in the reconstructed microchip packings (containing more than 3 x 10(5) spheres) was facilitated by the efficient use of supercomputer power. Porosity distributions and fluid flow velocity profiles for the reconstructed microchip packings are presented and analyzed. Aberrations from regular geometrical conduit shape are shown to influence packing structure and, thus, porosity and velocity distributions. Simulated axial dispersion coefficients are discussed with respect to their dependence on flow velocity and bed porosity. It is shown by comparison to experimental separation efficiencies that the simulated data genuinely reflect the general dispersion behavior of the real-life HPLC-microchip packings. Differences between experiment and simulation are explained by differing morphologies of real and simulated packings (intraparticle porosity, packing structure in the corner regions).

  4. Quantitative metabolite profiling of edible onion species by NMR and HPLC-MS.

    Science.gov (United States)

    Soininen, Tuula H; Jukarainen, Niko; Auriola, Seppo O K; Julkunen-Tiitto, Riitta; Karjalainen, Reijo; Vepsäläinen, Jouko J

    2014-12-15

    Allium genus is a treasure trove of valuable bioactive compounds with potentially therapeutically important properties. This work utilises HPLC-MS and a constrained total-line-shape (CTLS) approach applied to (1)H NMR spectra to quantify metabolites present in onion species to reveal important inter-species differences. Extensive differences were detected between the sugar concentrations in onion species. Yellow onion contained the highest and red onion the lowest amounts of amino acids. The main flavonol-glucosides were quercetin 3,4'-diglucoside and quercetin 4'-glucoside. In general, the levels of flavonols were, higher in yellow onions than in red onions, and garlic and leek contained a lower amount of flavonols than the other Allium species. Our results highlight how (1)H NMR together with HPLC-MS can be useful in the quantification and the identification of the most abundant metabolites, representing an efficient means to pinpoint important functional food ingredients from Allium species. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. Analysis of bioactivities and chemical composition of Ziziphus joazeiro Mart. using HPLC-DAD.

    Science.gov (United States)

    Brito, Sharlene M O; Coutinho, Henrique D M; Talvani, Andre; Coronel, Cathia; Barbosa, Andreza G R; Vega, Celeste; Figueredo, Fernando G; Tintino, Saulo R; Lima, Luciene F; Boligon, Aline A; Athayde, Margareth L; Menezes, Irwin R A

    2015-11-01

    The aim of this study was to evaluate the chemical profile and antioxidant, antimicrobial and antiparasitic activities of the hydroalcoholic extract of the leaves of Ziziphus joazeiro Mart. (HELZJ). The antioxidant DPPH and FRAP assays and chemical profile were determined by colorimetric methods and HPLC/DAD. The antiparasitic, antibiotic and antibiotic-modifying activity were evaluated by microdilution assays. The HPLC-DAD assay showed the presence of mostly tannins and flavonoids, such as caffeic acid and quercetin. The levels of polyphenols and flavonoids were 183.136 mg/g extract and 7.37 mg/g extract, respectively. DPPH and FRAP showed low antioxidant activity for the extract. The antibacterial and antifungal activities were not of clinical relevance, showing MIC>1024 μg/mL. However, synergism was observed between HELZJ and the antibiotics amikacin and gentamicin, which resulted in decreased bacterial drug resistance. EHFZJ showed low toxicity in fibroblasts in vitro, while antiparasitic results against Trypnosoma cruzi, Leishmania braziliensis and Leishmania infantum were not clinically relevant. Thus, our results indicate that Z. joazeiro Mart. (HELZJ) could be a source of plant-derived natural products that could lead to the development of promising new antibiotic compounds for infectious diseases. Copyright © 2014 Elsevier Ltd. All rights reserved.

  6. Determination of Arctiin and Arctigenin Contents in Arctium Tomentosum Mill. by HPLC Method

    Directory of Open Access Journals (Sweden)

    Xiaoying Zhou

    2011-01-01

    Full Text Available A simple, precise, rapid and accurate, binary-phase high performance liquid chromatographic method has been developed for the determination of arctiin and arctigenin contents in the Arctium tomentosumMill. with short run time. Chromatographic separation was achieved by using HPLC system, consisting of a Shimadzu LC-6AD and Kromasil C18 column (250×4.6 mm, 5 μm, with pre-column, the mobile phase consists of methanol and water (55: 45. Detection wavelength was 280 nm. The speed of flow was 1.0 mL/min. The specimen handing quantity was 10 μL. The arctiin’s linearity range was 1.575∼4.725 μg (r=0.9995. The arctigenin’s linearity range was 0.613, 3.063 μg (r = 0.9998 and the linear relationship was accurate. The average recovery (n=5 of arctiin and arctigenin were 101.55% (RSD=2.23% 101.63% (RSD =1.49 % respectively. The contents of arctiin and arctigenin in Arctium tomentosum Mill. were 10.69 mg/g and 0.15 mg/g, respectively. Therefore, the developed HPLC method can be applied to both in vitro studies of arctiin and arctigenin formulations as well as drug estimation in biological samples.

  7. Effective method for the detection of piroxicam in human plasma using HPLC

    Directory of Open Access Journals (Sweden)

    Adriana Maria CALVO

    2016-01-01

    Full Text Available Abstract Non-steroidal anti-inflammatory drugs (NSAIDs are widely used by the general population to alleviate inflammation and pain after oral surgeries. Piroxicam is among the most commonly used NSAIDs and excels in controlling pain, swelling, trismus and other common symptoms of inflammation. This study aimed to evaluate different concentrations of piroxicam and its major metabolite, 5’-hydroxypiroxicam, in human plasma samples over time using high performance liquid chromatography (HPLC after liquid-liquid extraction. Briefly, 10 volunteers participated in this study after approval by the Ethics Committee of Bauru School of Dentistry, Universidade de São Paulo – USP, Brazil. Volunteers received a single dose oral of piroxicam (20 mg and had blood collected at various times following an established protocol. The methodology of liquid-liquid extraction was effective for determining concentrations of piroxicam in plasma using HPLC in 10 out of 10 volunteers while 5’-hydroxypiroxicam was only detected in 2 out of 10 volunteers.

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

    Directory of Open Access Journals (Sweden)

    Mahmoud A. Tantawy

    2013-03-01

    Full Text Available 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 (D1 and derivative ratio (DD1 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.

  9. Development and Validation of Dissolution Test for Fluconazole Capsules by HPLC and Derivative UV Spectrophotometry

    Directory of Open Access Journals (Sweden)

    Josilene Chaves Ruela Corrêa

    2012-01-01

    Full Text Available The purpose of this study is to develop and validate a dissolution test for fluconazole, an antifungal used for the treatment of superficial, cutaneous, and cutaneomucous infections caused by Candida species, in capsules dosage form. Techniques by HPLC and UV first derivative spectrophotometry (UV-FDS were selected for quantitative evaluation. In the development of release profile, several conditions were evaluated. Dissolution test parameters were considered appropriate when a most discriminative release profile for fluconazole capsules was yielded. Dissolution test conditions for fluconazole capsules were 900 mL of HCl 0.1 M, 37 ± 0.5 °C using baskets with 50 rpm for 30 min of test. The developed HPLC and UV-FDS methods for the antifungal evaluation were selective and met requirements for an appropriate and validated method, according to ICH and USP requirements. Both methods can be useful in the registration process of new drugs or their renewal. For routine analysis application cost, simplicity, equipment, solvents, speed, and application to large or small workloads should be observed.

  10. HPLC Quantitative Analysis of Main Stilbenes and Flavones in Different Parts of Matteuccia struthiopteris

    Directory of Open Access Journals (Sweden)

    Shubei Li

    2013-01-01

    Full Text Available A simple and accurate HPLC-UV method was developed for the simultaneous quantitative analysis of main stilbenes and flavones in different parts (fronds, rhizomes, and frond bases of M. struthiopteris. The chromatographic separation was performed on a Kromasil C18 column (4.6 mm × 250 mm, 5 μm with the mobile phase of MeOH-H2O (including 0.1% phosphoric acid using a gradient elution at the flow rate of 1.0 mL min−1 and UV detection at 295 nm. The method was validated by specificity, linearity, accuracy (recovery, and precision tests (repeatability, intra- and interday. For all the six compounds, the linear regression coefficients ranged from 0.9958 to 0.9998 within the test ranges; intra- and interday precisions were <2% and the mean recoveries ranged from 98.09 to 103.56%. The amount of these compounds in the frond bases was almost the same as in the rhizomes but much higher than that in the fronds. The results indicate that the HPLC method developed was appropriate for the analysis of the six compounds in different parts (fronds, rhizomes, and frond bases of M. struthiopteris.

  11. Ultrasound-assisted extraction, HPLC analysis, and antioxidant activity of polyphenols from unripe apple.

    Science.gov (United States)

    Yue, Tianli; Shao, Dongyan; Yuan, Yahong; Wang, Zhouli; Qiang, Chunyan

    2012-08-01

    The polyphenols were extracted from the unripe apple assisted by a highly efficient and simple method of the ultrasound. Response surface methodology was used to investigate the effects of processing parameters, including ultrasound power, extraction time, temperature, and ethanol concentration on total polyphenols yield and polyphenols composition was analyzed by HPLC. Antioxidant activity of the polyphenols was evaluated as 2, 2-diphenyl-1-picrylhydracyl scavenging activity and inhibition activity of lipid peroxidation. The results showed that 10-100 times higher total polyphenols yield was obtained from the unripe apple than those from the reported apple pomace. The optimum extraction conditions were ultrasonic power of 519.39 W, extraction time of 30 min, extraction temperature 50°C, ethanol concentration of 50% gave the total polyphenols yield of 13.26 ± 0.56 mg GAE/g. HPLC analysis indicated that (-)-epicatechin, procyanidin B2, chlorogenic acid, and procyanidin B1 were the predominant polyphenols in unripe apple, which contributed to the higher antioxidant activity to 2, 2-diphenyl-1-picrylhydracyl of unripe apple polyphenols than other apple polyphenols. The extracted polyphenols had higher ability to inhibit lipid peroxidation than butylated hydroxy toluene, which demonstrated that the unripe apple polyphenols have the potential to be used as a substitute of some synthetic antioxidants. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Development and validation of an HPLC method for tetracycline-related USP monographs.

    Science.gov (United States)

    Hussien, Emad M

    2014-09-01

    A novel reversed-phase HPLC method was developed and validated for the assay of tetracycline hydrochloride and the limit of 4-epianhydrotetracycline hydrochloride impurity in tetracycline hydrochloride commercial bulk and pharmaceutical products. The method employed L1 (3 µm, 150 × 4.6 mm) columns, a mobile phase of 0.1% phosphoric acid and acetonitrile at a flow rate of 1.0 mL/min, and detection at 280 nm. The separation was performed in HPLC gradient mode. Forced degradation studies showed that tetracycline eluted as a spectrally pure peak and was well resolved from its degradation products. The fast degradation of tetracycline hydrochloride and 4-epianhydrotetracycline hydrochloride in solution was retarded by controlling the autosampler temperature at 4 °C and using 0.1% H3 PO4 as diluent. The robustness of the method was tested starting with the maximum variations allowed in the US Pharmacopeia (USP) general chapter Chromatography . The method was linear over the range 80-120% of the assay concentration (0.1 mg/mL) for tetracycline hydrochloride and 50-150% of the acceptance criteria specified in the individual USP monographs for 4-epianhydrotetracycline hydrochloride. The limit of quantification for 4-epianhydrotetracycline hydrochloride was 0.1 µg/mL, 20 times lower than the acceptance criteria. The method was specific, precise, accurate and robust. Copyright © 2014 John Wiley & Sons, Ltd.

  13. Direct UV Spectrophotometry and HPLC Determination of Triton X-100 in Split Virus Influenza Vaccine.

    Science.gov (United States)

    Pavlović, Bojana; Cvijetić, Nataša; Dragačević, Luka; Ivković, Branka; Vujić, Zorica; Kuntić, Vesna

    2016-01-01

    One of the most commonly used surfactants in the production of split virus influenza vaccine is nonionic surfactant Triton X-100. After splitting of the virus is accomplished, Triton X-100 is removed from the vaccine by subsequent production steps. Because of toxicity of Triton X-100, which remains in the vaccine in residual amounts, a sufficiently sensitive method for its detection and quantification needs to be defined. Two methods for determination of Triton X-100 residuals were developed: the UV-spectrophotometry and HPLC methods. For both methods, preparation of vaccine samples and removal of proteins and virus particles were crucial: samples were treated with methanol (1:1) and then centrifuged at 25 000 × g for 30 min. After such treatment, the majority of vaccine components that interfered in the UV region were removed, and diluted samples could be directly measured. The chromatographic system included C18 column, step methanol gradient, and detection at 225 nm with a single peak of Triton X-100 at 12.6 min. Both methods were validated and gave satisfactory results for accuracy, precision, specificity, linearity, and robustness. LOQ was slightly lower for the HPLC method. Hence, it was shown that both methods are suitable for analysis of residual amounts of Triton X-100, with the advantages of the UV method being its simplicity and availability in most laboratories.

  14. HPLC/MS-TOF Analysis of Surface Resins from Three Poplar Clones Grown in Serbia

    Directory of Open Access Journals (Sweden)

    Branislav Trudić

    2016-12-01

    Full Text Available Background and Purpose: Poplar clones grown in Serbia are fast growing tree species important for many different purposes in forestry and industry. In this study chemical content of the surface resins of three poplar clones grown in Serbia - M1, B229 and PE 19/66 was analyzed, aiming at their potential usage as a source of natural products important for pharmacy and chemotaxonomy. Materials and Methods: Using HPLC/MS-TOF we gained the first information on chemical compounds which comprise of resins on terminal twigs cuttings of commonly grown poplar clones. Provided from the nursery of the Institute of Lowland Forestry and Environment (Serbia, terminal twigs cuttings with leaves of different development stage from two year old seedlings of M1 poplar clone (Populus euramericana L., PE 19/66 clone and B229 clone (both belonging to Populus deltoides were sampled. The washing of the surface resins from terminal twigs cuttings of every sample was done with methylene-chloride until the samples were prepared for HPLC/MS-TOF analysis. Results: Out of 38 different compounds which were identified, M1 clone qualitatively differed for 14 compounds as compared to two other clones. Generally, the results showed that the composition of the resins consisted of different phenolic acids, phenolic esters, flavonoids and other contents. Conclusion: These three poplar clones are potent producers of pharmacologically and chemotaxonomically potent compounds in forest ecosystems, especially M1 clone.

  15. Determination of fructooligosaccharides in burdock using HPLC and microwave-assisted extraction.

    Science.gov (United States)

    Li, Jing; Liu, Xiaomei; Zhou, Bin; Zhao, Jing; Li, Shaoping

    2013-06-19

    The root of burdock ( Arctium lappa L.) is a commonly used vegetable in Asia. Fructooligosaccharides (FOS) are usually considered as its main bioactive components. Thus, quantitative analysis of these components is very important for the quality control of burdock. In this study, an HPLC-ELSD and microwave-assisted extraction method was developed for the simultaneous determination of seven FOS with degrees of polymerization (DP) between 3 and 9, as well as fructose, glucose, and sucrose in burdock from different regions. The separation was performed on a Waters XBridge Amide column (4.6 × 250 mm i.d., 3.5 μm) with gradient elution. All calibration curves for investigated analytes showed good linear regression (r > 0.9990). Their LODs and LOQs were lower than 3.63 and 24.82 μg/mL, respectively. The recoveries ranged from 99.2 to 102.6%. The developed method was successfully applied to determination of ten sugars in burdock from different locations of Asia. The results showed that the contents of FOS in different samples of burdock collected at appropriate times were similar, and the developed HPLC-ELSD with microwave-assisted extraction method is helpful to control the quality of burdock.

  16. [Spectrum-effect Relationship Between Total Antioxidant Activity and HPLC Fingerprint of Arctium lappa Root].

    Science.gov (United States)

    Wang, Xiao-juan; Jiang, Lin

    2014-12-01

    To explore the spectrum-effect relationship between the HPLC fingerprint of Arctium lappa root methanol extract and the total antioxidant activity. The experiment was carried out with Gemini C18 110A (250 mm x 4.6 mm, 5 µm) column using methanol-0.04% phosphoric acid as gradient mobile phase at the flow rate of 1.0 mL/min, detection wavelength of 320 nm. The total antioxidant activity was determined by measuring the absorbance of each sample after being reacted with ammonium molybdate reagent. The spectrum-effect relationship was investigated using canonical correlation analysis (CCA). The spectrum-effect relationship between the HPLC fingerprint of Arctium lappa root methanol extract and the total antioxidant activity were established, the similarity of fingerprint of all samples was above 0.9. Peaks 1, 6, 9, 12 and 14 were principle components of Arctium lappa root for the total antioxidant activity. This method contributes to the fast comprehensive evaluation of quality of Arctium lappa root.

  17. UPLC and HPLC of caffeoyl esters in wild and cultivated Arctium lappa L.

    Science.gov (United States)

    Haghi, Ghasem; Hatami, Alireza; Mehran, Mehdi

    2013-05-01

    Analytical methods including ultra-performance liquid chromatography (UPLC) and high-performance liquid chromatography (HPLC) with photodiode array (PDA) detector were developed for the analysis of caffeoylquinic acid derivatives in seeds, leaves and roots of Arctium lappa L. Separation was performed on C(18) column utilising 5% (v/v) acetic acid in water and acetonitrile at 330 nm. Both methodologies were validated in terms of linearity, precision, and recovery. The results showed that the major advantages of UPLC, over HPLC were the fast analysis, narrow peaks, high sensitivity, and reduction of solvent consumption. Subsequently the methods were applied for the identification and quantification of chlorogenic acid (5-CQA) and 1,5-dicaffeoylquinic acid (1,5-DCQA) as main compounds in samples. The total phenolic content of samples ranged from 3.93 to 14.13 g of 5-CQA equivalent/100g dry weight (DW). There was a significant variability from 89 to 571 mg/100g for 5-CQA and 48 to 486 mg/100g for 1,5-DCQA in dry material. Copyright © 2012 Elsevier Ltd. All rights reserved.

  18. Analysis of Dithiocarbamate Fungicides in Vegetable Matrices Using HPLC-UV Followed by Atomic Absorption Spectrometry.

    Science.gov (United States)

    Al-Alam, Josephine; Bom, Laura; Chbani, Asma; Fajloun, Ziad; Millet, Maurice

    2017-04-01

    A simple method combining ion-pair methylation, high-performance liquid chromatography (HPLC) analysis with detection at 272 nm and atomic absorption spectrometry was developed in order to determine 10 dithiocarbamate fungicides (Dazomet, Metam-sodium, Ferbam, Ziram, Zineb, Maneb, Mancozeb, Metiram, Nabam and Propineb) and distinguish ethylenbisdithiocarbamates (EBDTCs) Zineb, Maneb and Mancozeb in diverse matrices. This method associates reverse phase analysis by HPLC analysis with detection at 272 nm, with atomic absorption spectrometry in order to distinguish, with the same extraction protocol, Maneb, Mancozeb and Zineb. The limits of detection (0.4, 0.8, 0.5, 1.25 and 1.97) and quantification (1.18, 2.5, 1.52, 4.2 and 6.52) calculated in injected nanogram, respectively, for Dazomet, Metam-Na, dimethyldithiocarbamates (DMDTCs), EBDTCs and propylenebisdithiocarbamates (PBDTCs) justify the sensitivity of the method used. The coefficients of determination R2 were 0.9985, 0.9978, 0.9949, 0.988 and 0.9794, respectively, for Dazomet, Metam-Na, DMDTCs, EBDTCs and PBDTCs, and the recovery from fortified apple and leek samples was above 90%. Results obtained with the atomic absorption method in comparison with spectrophotometric analysis focus on the importance of the atomic absorption as a complementary specific method for the distinction between different EBDTCs fungicides. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  19. [Determination of oleanolic acid in fufang zhenqin feining capsules by RP-HPLC].

    Science.gov (United States)

    Rong, Lu-Ping; Chen, Yi-Shen; Liao, Hua-Wei; Wan, Zheng-Lan

    2013-08-01

    To investigate the optimal technology of extraction of fufang zhenqin feining capsules and establish a method for determination its oleanolic acid. Orthogonal test was employed for selecting the optimum extraction technology by the index of the content of oleanolic acid in extraction. HPLC was performed on a C18 (250 mm x 4.6 mm, 5 microm) column using methanol-0.3% triethylamine solution (80: 20) as the mobile phase at a flow rate of 1 ml/min. The detection wavelength was set at 210 nm. The column temperature was 30 degrees C and the injection size was 25 microL. The optimum extraction technology was as follows: the concertration of alcohol was 70%, the ratio of solid/material was 8: 1, extracting 3 times with half an hour for each time. The linear range of oleanolic acid was 59.68 - 596.8 microg/ml (r = 0.9997), the average recovery was 99.79% (RSD = 0.5%). The considerable extraction rate of active components in the drugs is achieved by applying the selected technology, and the simple method is fit for production. The established HPLC method is simple, accurate, special and can be used for the quality control of fufang zhenqin feining capsules.

  20. Solid phase extraction and determination of carbamate pesticides in water samples by reverse-phase HPLC

    Energy Technology Data Exchange (ETDEWEB)

    Moreno-Tovar, J.; Santos-Delgado, M.J. [Departamento de Quimica Analitica, Facultad de ciencias Quimicas, Universidad Complutense de Madrid (Spain)

    1995-12-31

    Solid phase extraction. SPE. using C{sub 1}8 bonded silica cartridges for trace amounts determination of carbaryl, propoxur, thiram, propham and methiocarb in water samples was studied and the breakthrough volume of the cartridges was established. The high enrichment factor and large injection volume admissible in the isocratic reverse-phase HPLC system allows pesticides determination with UV detection at 22o nm even at a concentration lower than 0.05 mug/L. Purified tap natural and underground water samples were spiked with carbamate pesticides in the concentration range 0.16-16.0 mug/L. Large volumes of samples (up to 2L) were passed through available C{sub 1}8, cartridges and eluted with acetonitrile. The preconcentrated samples were analyzed by HPLC using a Spherisorb ODS column with a 42.58 acetonitrile-water mobile phase. From replicate samples, recovery for the pesticides ranged from 79.0 to 103.7% except for thiran which is not retained. Tehe relative standard deviation (n=4 at 0.16 to 1.61 mug/L concetration level) range from 1.1 to 6.8%. (Author) 14 refs.

  1. HPLC determination and clinical significance of serum prednisone in patients with nephrotic syndrome

    Science.gov (United States)

    Chen, Chun-Mei; Xia, Yun-Cheng; Zhang, Xu-Guang; Peng, Can-Hui; Liu, Fu-You; Peng, You-Ming; Sun, Lin

    2014-01-01

    Aim: A rapid protocol is necessary to determine the serum concentrations of prednisone. Methods: The HP1100 high-performance liquid chromatographic (HPLC) system was employed. The HP Lichrosphere C8 column (250 mm × 4 mm, i.d., 5 μm particle size) was used. The mobile phase was methanol, tetrahydrofuran and water in the ratio 25:25:50. The flow rate was 1.0 ml/min. The sample was monitored by UV absorbance at 240 nm. Acetanilide was used as the internal standard, and methanol was added into the serum for depositing the protein. Results: The chromatography was effective and was not interfered with by the serum components. Good linearity was observed, within the range of 10-500 μg/L for prednisone, and the detection limit was 5 μg/L. The serum concentrations of prednisone between the nephrotic syndrome (NS) group and the control group were significantly different (P 0.05). The serum ncentration of prednisone in the steroid-resistant group was lower than that in the steroid-sensitive group (P < 0.05). Conclusions: HPLC is a practical and reliable method to determine the serum concentration of prednisone with high accuracy, precision, linearity and repeatability. PMID:25664064

  2. Solicitation of HPLC and HPTLC Techniques for Determination of Rutin from Polyalthia longifolia Thwaites

    Science.gov (United States)

    Doshi, Gaurav Mahesh; Zine, Sandeep Prabhakar; Chaskar, Pratip Kashinath; Une, Hemant Devidas

    2014-01-01

    Background: Polyalthia longifolia Thwaites is an important traditional plant in India. Rutin, an active constituent has been reported to possess good amount of pharmacological as well as therapeutic potential. Objective: The aim of the present study was to find out by analytical techniques how much percentage of rutin is present in the plant leaves’ ethanolic extract by analytical techniques. Materials and Methods: Shade dried leaves of Polyalthia longifolia were subjected to cold ethanolic extraction followed by monitoring the isolated rutin high-pressure liquid chromatography (HPLC) and high performance thin layer chromatography (HPTLC) after carrying out preliminary phytochemical screening. Results: Extraction yield was found to be 13.94% w/w. Phytochemical screening of the extract showed the presence of flavonoids, steroids, diterpenoids, alkaloids, saponins, tannins and phenolic compounds and mucilage. From the Rf value, the ethanolic extract was found to be having constituent identical to rutin. By HPTLC and HPLC the amount of rutin was found to be 11.60% w/w and 4.03% w/v, respectively. Conclusion: The active constituent isolated was found to be equal to rutin. PMID:25002804

  3. HPLC-DAD-ESI-MS Analysis of Flavonoids from Leaves of Different Cultivars of Sweet Osmanthus.

    Science.gov (United States)

    Wang, Yiguang; Fu, Jianxin; Zhang, Chao; Zhao, Hongbo

    2016-09-14

    Osmanthus fragrans Lour. has traditionally been a popular ornamental plant in China. In this study, ethanol extracts of the leaves of four cultivar groups of O. fragrans were analyzed by high-performance liquid chromatography coupled with diode array detection (HPLC-DAD) and high-performance liquid chromatography with electrospray ionization and mass spectrometry (HPLC-ESI-MS). The results suggest that variation in flavonoids among O. fragrans cultivars is quantitative, rather than qualitative. Fifteen components were detected and separated, among which, the structures of 11 flavonoids and two coumarins were identified or tentatively identified. According to principal component analysis (PCA) and hierarchical cluster analysis (HCA) based on the abundance of these components (expressed as rutin equivalents), 22 selected cultivars were classified into four clusters. The seven cultivars from Cluster III ('Xiaoye Sugui', 'Boye Jingui', 'Wuyi Dangui', 'Yingye Dangui', 'Danzhuang', 'Foding Zhu', and 'Tianxiang Taige'), which are enriched in rutin and total flavonoids, and 'Sijigui' from Cluster II which contained the highest amounts of kaempferol glycosides and apigenin 7-O-glucoside, could be selected as potential pharmaceutical resources. However, the chemotaxonomy in this paper does not correlate with the distribution of the existing cultivar groups, demonstrating that the distribution of flavonoids in O. fragrans leaves does not provide an effective means of classification for O. fragrans cultivars based on flower color.

  4. Determination of zearalenone in traditional Chinese medicinal plants and related products by HPLC-FLD.

    Science.gov (United States)

    Zhang, Xiaofei; Liu, Wenkun; Logrieco, Antonio F; Yang, Meihua; Ou-yang, Zhen; Wang, Xiong; Guo, Qi

    2011-01-01

    A HPLC-FLD method has been developed and validated for zearalenone (ZON) in 107 widely consumed Chinese medicinal herbs and related products collected from different regions of China. Samples were extracted with methanol/water (80 : 20, v/v), and the extracts were cleaned-up through immunoaffinity columns (IAC). ZON was quantified by HPLC with fluorescence detection. Recoveries from three different medicinal herbs spiked with ZON at levels ranging from 30 to 600 µg kg(-1) were from 80.8 to 98.3%. The limit of detection was 9.5 µg kg(-1), based on a signal-to-noise ratio of 3 : 1. Naturally occurring ZON was only found in coix seed medicinal herb (all nine samples), with levels ranging from 18.7 to 211.4 µg kg(-1). Positive results were confirmed by UV spectrum and LC-ESI-MS/MS. This is the first report of ZON contamination of a Chinese medicinal herb.

  5. Chromatographic analyses of fatty acid methyl esters by HPLC-UV and GC-FID

    Energy Technology Data Exchange (ETDEWEB)

    Carvalho, Myller S.; Pinho, David M.M.; Suarez, Paulo A.Z., E-mail: psuarez@unb.br [Laboratorio de Materiais e Combustiveis, Instituto de Quimica, Universidade de Brasilia, DF (Brazil); Mendonca, Marcio A. [Faculdade de Agronomia e Medicina Veterinaria, Universidade de Brasilia, DF (Brazil); Resck, Ines S. [Laboratorio de Ressonancia Magnetica Nuclear, Universidade de Brasilia, DF (Brazil)

    2012-04-15

    An analytical method using high performance liquid chromatography with UV detection (HPLC-UV) (method A) was used for simultaneous determination of total amounts of triacylglycerides, diacylglycerides, monoacylglycerides and fatty acid methyl esters in alcoholysis of different oil (cotton, canola, sunflower, corn and soybean) samples. Analyses were carried out at 40 deg C for 20 min using a gradient of methanol (MeOH) and 2-propanol-hexane 5:4 (v/v) (PrHex): 100% of MeOH in 0 min, 50% of MeOH and 50% of PrHex in 10 min maintained with isocratic elution for 10 min. Another HPLC-UV method (method B) with acetonitrile isocratic elution for 34 min was used to determine the fatty acid composition of oils analyzing their methyl ester derivatives. Contents were determined with satisfactory repeatability (relative standard deviation, RSD < 3%), linearity (r{sup 2} > 0.99) and sensitivity (limit of quantification). Method B was compared with an official gas chromatographic method with flame ionization detection (GC-FID) from American Oil Chemists' Society (AOCS) in the determination of fatty acid methyl esters (FAME) in biodiesel real samples. (author)

  6. HPLC method for rapidly following biodiesel fuel transesterification reaction progress using a core-shell column

    Energy Technology Data Exchange (ETDEWEB)

    Allen, Samuel J.; Ott, Lisa S. [California State University, Chico, CA (United States)

    2012-07-15

    There are a wide and growing variety of feedstocks for biodiesel fuel. Most commonly, these feedstocks contain triglycerides which are transesterified into the fatty acid alkyl esters (FAAEs) which comprise biodiesel fuel. While the tranesterification reaction itself is simple, monitoring the reaction progress and reaction products is not. Gas chromatography-mass spectrometry is useful for assessing the FAAE products, but does not directly address either the tri-, di-, or monoglycerides present from incomplete transesterification or the free fatty acids which may also be present. Analysis of the biodiesel reaction mixture is complicated by the solubility and physical property differences among the components of the tranesterification reaction mixture. In this contribution, we present a simple, rapid HPLC method which allows for monitoring all of the main components in a biodiesel fuel transesterification reaction, with specific emphasis on the ability to monitor the reaction as a function of time. The utilization of a relatively new, core-shell stationary phase for the HPLC column allows for efficient separation of peaks with short elution times, saving both time and solvent. (orig.)

  7. 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.

  8. A validated HPLC method for separation and determination of promethazine enantiomers in pharmaceutical formulations.

    Science.gov (United States)

    Saleh, Ola A; El-Azzouny, Aida A; Aboul-Enein, Hassan Y; Badawy, Amr M

    2009-01-01

    A simple, rapid, and validated method for separation and determination of promethazine enantiomers was developed. Promethazine was separated and quantitated on a Vancomycin Chirobiotic V column (250 x 4.6 mm), using a mixture of methanol, acetic acid, and triethylamine (100:0.1:0.1%, by volume) as a mobile phase at 20 degrees C and at a flow rate of 1 mL/min. The UV-detector was set to 254 nm. Acetyl salicylic acid (Aspirin) was used as an internal standard. The applied HPLC method allowed separation and quantification of promethazine enantiomers with good linearity (r > .999) in the studied range. The relative standard deviations (RSD) were 0.29 and 0.36 for the promethazine enantiomers with accuracy of 100.06 and 100.08. The limit of detection and limit of quantification of promethazine enantiomers were found to be 0.04 and 0.07 microg/mL, respectively. The method was validated through the parameters of linearity, accuracy, precision, and robustness. The HPLC method was applied for the quantitative determination of promethazine in pharmaceutical formulations.

  9. 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.

  10. A single extraction and HPLC procedure for simultaneous analysis of phytosterols, tocopherols and lutein in soybeans.

    Science.gov (United States)

    Slavin, Margaret; Yu, Liangli Lucy

    2012-12-15

    A saponification/extraction procedure and high performance liquid chromatography (HPLC) analysis method were developed and validated for simultaneous analysis of phytosterols, tocopherols and lutein (a carotenoid) in soybeans. Separation was achieved on a phenyl column with a ternary, isocratic solvent system of acetonitrile, methanol and water (48:22.5:29.5, v/v/v). Evaporative light scattering detection (ELSD) was used to quantify β-sitosterol, stigmasterol, campesterol, and α-, δ- and γ-tocopherols, while lutein was quantified with visible light absorption at 450 nm. Peak identification was verified by retention times and spikes with external standards. Standard curves were constructed (R(2)>0.99) to allow for sample quantification. Recovery of the saponification and extraction was demonstrated via analysis of spiked samples. Also, the accuracy of results of four soybeans using the described saponification and HPLC analytical method was validated against existing methods. This method offers a more efficient alternative to individual methods for quantifying lutein, tocopherols and sterols in soybeans. Copyright © 2012 Elsevier Ltd. All rights reserved.

  11. Monitoring by HPLC of Chamomile Flavonoids Exposed to Rat Liver Microsomal Metabolism

    Science.gov (United States)

    Petroianu, Georg; Szőke, Éva; Kalász, Huba; Szegi, Péter; Laufer, Rudolf; Benkő, Bernadett; Darvas, Ferenc; Tekes, Kornélia

    2009-01-01

    Three major flavonoid chamomile components (quercetin, apigenin-7-O-glucoside and rutin) were subjected to oxidative metabolism by cytochrome P-450 of rat liver microsomal preparations. Changes over time in their respective concentrations were followed using reversed-phase HPLC with UV detection. No clean-up had to be applied as only the specific flavonoid had to be separated from the background components originating from the rat liver microsome. Neither the concentration of apigenin-7-O-glucoside nor that of the diglycoside rutin decreased during one hour of exposure to rat microsomal treatment. In contrast, the concentration of quercetin, a lipophilic aglycon, decreased. Our analytical HPLC results complement the in silico calculated lipophilicity (logP) of these compounds; the relatively high lipophilicity of quercetin appears to predispose it to oxidative metabolism in order to decrease its fat solubility. In contrast the much less lipophilic compounds apigenin-7-O-glucoside and rutin were resistant in vitro to microsomal treatment. PMID:19707521

  12. Fingerprint analysis of polysaccharides from different Ganoderma by HPLC combined with chemometrics methods.

    Science.gov (United States)

    Sun, Xiaomei; Wang, Haohao; Han, Xiaofeng; Chen, Shangwei; Zhu, Song; Dai, Jun

    2014-12-19

    A fingerprint analysis method has been developed for characterization and discrimination of polysaccharides from different Ganoderma by high performance liquid chromatography (HPLC) coupled with chemometrics means. The polysaccharides were extracted under ultrasonic-assisted condition, and then partly hydrolyzed with trifluoroacetic acid. Monosaccharides and oligosaccharides in the hydrolyzates were subjected to pre-column derivatization with 1-phenyl-3-methyl-5-pyrazolone and HPLC analysis, which will generate unique fingerprint information related to chemical composition and structure of polysaccharides. The peak data were imported to professional software in order to obtain standard fingerprint profiles and evaluate similarity of different samples. Meanwhile, the data were further processed by hierarchical cluster analysis and principal component analysis. Polysaccharides from different parts or species of Ganoderma or polysaccharides from the same parts of Ganoderma but from different geographical regions or different strains could be differentiated clearly. This fingerprint analysis method can be applied to identification and quality control of different Ganoderma and their products. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. Optimization of Robust HPLC Method for Quantitation of Ambroxol Hydrochloride and Roxithromycin Using a DoE Approach.

    Science.gov (United States)

    Patel, Rashmin B; Patel, Nilay M; Patel, Mrunali R; Solanki, Ajay B

    2017-03-01

    The aim of this work was to develop and optimize a robust HPLC method for the separation and quantitation of ambroxol hydrochloride and roxithromycin utilizing Design of Experiment (DoE) approach. The Plackett-Burman design was used to assess the impact of independent variables (concentration of organic phase, mobile phase pH, flow rate and column temperature) on peak resolution, USP tailing and number of plates. A central composite design was utilized to evaluate the main, interaction, and quadratic effects of independent variables on the selected dependent variables. The optimized HPLC method was validated based on ICH Q2R1 guideline and was used to separate and quantify ambroxol hydrochloride and roxithromycin in tablet formulations. The findings showed that DoE approach could be effectively applied to optimize a robust HPLC method for quantification of ambroxol hydrochloride and roxithromycin in tablet formulations. Statistical comparison between results of proposed and reported HPLC method revealed no significant difference; indicating the ability of proposed HPLC method for analysis of ambroxol hydrochloride and roxithromycin in pharmaceutical formulations. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  14. CZE/PAD and HPLC-UV/PAD Profile of Flavonoids from Maytenus aquifolium and Maytenus ilicifolia “espinheira santa” Leaves Extracts

    OpenAIRE

    Cristina A. Diagone; Renata Colombo; Lanças, Fernando M.; Yariwake, Janete H.

    2012-01-01

    This paper describes the application of HPLC and CZE to analyze flavonoids in the leaves of Maytenus ilicifolia and Maytenus aquifolium, which are species widely used in Brazilian folk medicine. The two species showed different flavonoid profiles, but acidic hydrolysis of the Maytenus extracts confirmed that all these compounds are quercetin or kaempferol derivatives. A comparison of the CZE and HPLC profiles of Maytenus extracts showed numerous flavonoid peaks using HPLC. However, the advant...

  15. Adsorption Kinetics of Carbamate Pesticide in Rice Field Soil

    Directory of Open Access Journals (Sweden)

    Soontree Khuntong

    2010-07-01

    Full Text Available Ultrasonic extraction (75.55% with petroleum ether:acetone (1:1, v/v was employed for extraction of carbofuran in rice field soil. The amounts of carbofuran were determined by reverse phase HPLC. The analytical method provided high precision and accuracy with the relative error of 0.47%. The percentage of recoveries varied from 84% to 77% in the con¬centration ranges of 10–40 mg/L of spiked soil samples. The carbofuran residues in the rice field soil significantly decreased year by year because of pesticide properties, soil properties and degradation conditions. A high amount of residues was found in the plots that contained high organic contents. The adsorption of carbofuran in soil reached equilibrium within 23 h. The percentage of adsorption varied from almost 30% to 80% depending on concentrations of carbofuran. The adsorption of carbofuran agreed with Freundlich isotherms; q = 7.07 x 10-5Cf2.5092; with the correlation coefficient of 0.9281. Organic carbon coefficient, Koc, was 1.91 x 10-3 mg/L calculated from Kd, and half-life (8.9 d of adsorbed carbofuran. The GUS index (6.37 calculated from Koc presented a high lixiviation potential. The positive ΔG indicated the non-spontaneous reaction. Carbofuran rapidly desorbed from soil at the desorption rate of 0.0228 mg/kg soil d. Kinetic studies provided the first order reaction with the reaction rate of 0.0779 mg/d and half-life of 8.9 days.

  16. Analysis of kinetic reaction mechanisms

    CERN Document Server

    Turányi, Tamás

    2014-01-01

    Chemical processes in many fields of science and technology, including combustion, atmospheric chemistry, environmental modelling, process engineering, and systems biology, can be described by detailed reaction mechanisms consisting of numerous reaction steps. This book describes methods for the analysis of reaction mechanisms that are applicable in all these fields. Topics addressed include: how sensitivity and uncertainty analyses allow the calculation of the overall uncertainty of simulation results and the identification of the most important input parameters, the ways in which mechanisms can be reduced without losing important kinetic and dynamic detail, and the application of reduced models for more accurate engineering optimizations. This monograph is invaluable for researchers and engineers dealing with detailed reaction mechanisms, but is also useful for graduate students of related courses in chemistry, mechanical engineering, energy and environmental science and biology.

  17. Dissolution Kinetics of Alumina Calcine

    Energy Technology Data Exchange (ETDEWEB)

    Batcheller, Thomas Aquinas

    2001-09-01

    Dissolution kinetics of alumina type non-radioactive calcine was investigated as part of ongoing research that addresses permanent disposal of Idaho High Level Waste (HLW). Calcine waste was produced from the processing of nuclear fuel at the Idaho Nuclear Technology and Engineering Center (INTEC). Acidic radioactive raffinates were solidified at ~500°C in a fluidized bed reactor to form the dry granular calcine material. Several Waste Management alternatives for the calcine are presented in the Idaho High Level Waste Draft EIS. The Separations Alternative addresses the processing of the calcine so that the HLW is ready for removal to a national geological repository by the year 2035. Calcine dissolution is the key front-end unit operation for the separations alternative.

  18. Kinetics on cocondensation of phenol and urea

    Science.gov (United States)

    Bunichiro Tomita; Yasunori Yoshida; Chung-Yun. Hse

    1993-01-01

    The chemical kinetics on cocondensation between methylolphenols and urea under acidic condition were investigated using 2- and 4-hydroxybenzyl alcohols as well as 2,4,6-trimethylolphenol as model compounds. The reactivity of the cocondensation were compared between o- and p-methylol groups. Moreover, the kinetics on self-condensations of monomethylolphenols and...

  19. Inflation Rates, Car Devaluation, and Chemical Kinetics.

    Science.gov (United States)

    Pogliani, Lionello; Berberan-Santos, Mario N.

    1996-01-01

    Describes the inflation rate problem and offers an interesting analogy with chemical kinetics. Presents and solves the car devaluation problem as a normal chemical kinetic problem where the order of the rate law and the value of the rate constant are derived. (JRH)

  20. Kinetic spectrophotometric determination of some fluoroquinolone ...

    African Journals Online (AJOL)

    A simple and sensitive kinetic spectrophotometric method was developed for the determination of some fluoroquinolonea antibiotics; gemifloxacin mesylate, moxifloxacin hydrochloride and gatifloxacin in bulk and in pharmaceutical preparations. The method is based upon a kinetic investigation of the oxidation reaction of ...

  1. Modeling composting kinetics: A review of approaches

    NARCIS (Netherlands)

    Hamelers, H.V.M.

    2004-01-01

    Composting kinetics modeling is necessary to design and operate composting facilities that comply with strict market demands and tight environmental legislation. Current composting kinetics modeling can be characterized as inductive, i.e. the data are the starting point of the modeling process and

  2. Thermal degradation kinetics and solid state, temperature ...

    Indian Academy of Sciences (India)

    WINTEC

    Phenothiazine derivatives belong to a big group of aromatic compounds. These derivatives are substituted in ... Elemental analysis for carbon, hydrogen, nitrogen and sulphur were done using Vario EL III CHNS ... The aim of the kinetic study of thermal analysis data is to find out the most probable kinetic model which best ...

  3. Towards Free-Form Kinetic Structures

    DEFF Research Database (Denmark)

    Parigi, Dario; Kirkegaard, Poul Henning

    2012-01-01

    of pin-slot paths starting from the local displacements of element [2] [3]. In the design of kinetic structures, in particular when complex three dimensional and non regular configurations are involved, the functionality is frequently related to a global displacement capability of the assembly rather...... for the generation of free-form kinetic structures....

  4. Saffman-Taylor fingers with kinetic undercooling

    KAUST Repository

    Gardiner, Bennett P. J.

    2015-02-23

    © 2015 American Physical Society. The mathematical model of a steadily propagating Saffman-Taylor finger in a Hele-Shaw channel has applications to two-dimensional interacting streamer discharges which are aligned in a periodic array. In the streamer context, the relevant regularization on the interface is not provided by surface tension but instead has been postulated to involve a mechanism equivalent to kinetic undercooling, which acts to penalize high velocities and prevent blow-up of the unregularized solution. Previous asymptotic results for the Hele-Shaw finger problem with kinetic undercooling suggest that for a given value of the kinetic undercooling parameter, there is a discrete set of possible finger shapes, each analytic at the nose and occupying a different fraction of the channel width. In the limit in which the kinetic undercooling parameter vanishes, the fraction for each family approaches 1/2, suggesting that this "selection" of 1/2 by kinetic undercooling is qualitatively similar to the well-known analog with surface tension. We treat the numerical problem of computing these Saffman-Taylor fingers with kinetic undercooling, which turns out to be more subtle than the analog with surface tension, since kinetic undercooling permits finger shapes which are corner-free but not analytic. We provide numerical evidence for the selection mechanism by setting up a problem with both kinetic undercooling and surface tension and numerically taking the limit that the surface tension vanishes.

  5. COMPARATIVE ANALYSIS OF SOME EXISTING KINETIC MODELS ...

    African Journals Online (AJOL)

    In terms of highest values of R2, first proposed model accounted for 46.7%, Pseudo second-order kinetics model 40% while Elovich, Webber-Morris and second proposed kinetic models accounted for 6.7% respectively of the total results for biosorption of the three heavy metals by five selected microorganisms. But based ...

  6. Enhancing Thai Students' Learning of Chemical Kinetics

    Science.gov (United States)

    Chairam, Sanoe; Somsook, Ekasith; Coll, Richard K.

    2009-01-01

    Chemical kinetics is an extremely important concept for introductory chemistry courses. The literature suggests that instruction in chemical kinetics is often teacher-dominated at both the secondary school and tertiary levels, and this is the case in Thailand--the educational context for this inquiry. The work reported here seeks to shift students…

  7. Thermodynamic, kinetic and mechanistic investigations of ...

    Indian Academy of Sciences (India)

    standardized by iodometric titration and gravimetrically by the thiocyanate23 method. 2.3 Kinetic Measurements. Kinetics was followed under pseudo first order con- ditions where [PPZ] > [DPC] at 25 ± 0.1◦C, unless otherwise specified. The reaction was initiated by mix- ing the DPC to PPZ solution, which also contained.

  8. A Comprehensive Enzyme Kinetic Exercise for Biochemistry

    Science.gov (United States)

    Barton, Janice S.

    2011-01-01

    This article describes a comprehensive treatment of experimental enzyme kinetics strongly coupled to electronic data acquisition and use of spreadsheets to organize data and perform linear and nonlinear least-squares analyses, all in a manner that promotes development of important reasoning skills. Kinetic parameters are obtained for the stable…

  9. Kinetic energy driven pairing in cuprate superconductors

    NARCIS (Netherlands)

    Maier, TA; Jarrell, M; Macridin, A; Slezak, C

    2004-01-01

    Pairing occurs in conventional superconductors through a reduction of the electronic potential energy accompanied by an increase in kinetic energy. In the underdoped cuprates, optical experiments show that pairing is driven by a reduction of the electronic kinetic energy. Using the dynamical cluster

  10. Concepts of radial and angular kinetic energies

    DEFF Research Database (Denmark)

    Dahl, Jens Peder; Schleich, W.P.

    2002-01-01

    We consider a general central-field system in D dimensions and show that the division of the kinetic energy into radial and angular parts proceeds differently in the wave-function picture and the Weyl-Wigner phase-space picture, Thus, the radial and angular kinetic energies are different quantities...

  11. A Method of Hepatocyte Extraction Conjugated with HPLC is Established for Screening Potential Active Components in Chinese Medicines—Probing Herba Artemisiae Scopariae as an Exemplifying Approach

    Directory of Open Access Journals (Sweden)

    Hong-Wei Fan

    2012-02-01

    Full Text Available In order to establish an effective and quick method for screening potential bioactive compounds in Traditional Chinese Medicines (TCMs, hepatocytes were employed for extracting either bifendate, a clinical medicine for liver diseases, or chemicals in Herba Artemisiae Scopariae (A. Scopariae, a commonly used traditional Chinese medicine for remedying liver diseases such as hepatitis induced by viruses, chemicals or alcohol. After hepatocyte extraction the compounds were analyzed by HPLC, therefore this method was referrred to as hepatocyte extraction conjugated with HPLC (HE-HPLC. In the first part of this study, HE-HPLC showed that bifendate was extracted by hepatocytes and detected by HPLC-DAD which indicated the feasibility of this method. Then in the second part of the study, the potential active components in the A. scopariae extract were studied using HE-HPLC. Six chemicals in the A. scopariae extract, which could bind to hepatocytes in vitro, were detected by HPLC-DAD and three were identified as 7-hydroxy-coumarin (7-OH-C, capillartemisin A and 7-methoxy-coumarin, respectively. In vitro assays showed that 7-OH-C protected HL-7702 hepatocytes from H2O2 injury. The results indicated that these compounds could be extracted by hepatocytes, could be detected by HPLC and more importantly were bioactive. It is suggested that HE-HPLC is a useful method for screening potent active components in Chinese medicines used to treat liver diseases.

  12. Comparison of HPLC, UV spectrophotometry and potentiometric titration methods for the determination of lumefantrine in pharmaceutical products.

    Science.gov (United States)

    da Costa César, Isabela; Nogueira, Fernando Henrique Andrade; Pianetti, Gérson Antônio

    2008-09-10

    This paper describes the development and evaluation of a HPLC, UV spectrophotometry and potentiometric titration methods to quantify lumefantrine in raw materials and tablets. HPLC analyses were carried out using a Symmetry C(18) column and a mobile phase composed of methanol and 0.05% trifluoroacetic acid (80:20), with a flow rate of 1.0ml/min and UV detection at 335nm. For the spectrophotometric analyses, methanol was used as solvent and the wavelength of 335nm was selected for the detection. Non-aqueous titration of lumefantrine was carried out using perchloric acid as titrant and glacial acetic acid/acetic anhydride as solvent. The end point was potentiometrically determined. The three evaluated methods showed to be adequate to quantify lumefantrine in raw materials, while HPLC and UV methods presented the most reliable results for the analyses of tablets.

  13. A new approach to the analysis of nicarbazin and ionophores in eggs by HPLC/MS/MS.

    Science.gov (United States)

    Dmitrovic, Jasna; Durden, David A

    2011-01-01

    An HPLC/MS/MS method has been developed and validated for the quantification and confirmation of nicarbazin and ionophores (lasalocid, monensin, salinomycin, and narasin) in eggs. Nicarbazin is determined in the negative electrospray mode with a basic mobile phase that supports creation of negative ions. Consequently, our ability to maintain instrument sensitivity over time has significantly improved. The analysis of the ionophores is done in the positive electrospray mode using ammonium buffer for HPLC separation. Monitoring ammonium adduct parent ions resulted in enhanced sensitivity and better reproducibility of the ionophore analysis. The validation of this improved HPLC/MS/MS method for the detection of nicarbazin and the ionophores demonstrated excellent precision of below 10% RSD and lower LOD values (microg/kg) for nicarbazin (0.018), lasalocid (0.015), monensin (0.015), salinomycin (0.033), and narasin (0.039).

  14. A validated stability indicating DAD–HPLC method for determination of pentoxifylline in presence of its pharmacopeial related substances

    Directory of Open Access Journals (Sweden)

    Mohamed A. Korany

    2013-12-01

    Full Text Available A validated, simple and sensitive stability-indicating HPLC method was introduced for the analysis of Pentoxifylline in the presence of its pharmacopeial related substances, Caffeine anhydrous and Theophylline anhydrous, in the presence of its forced degradation products. This was achieved using a gradient DAD–HPLC method in order to achieve a good separation between the related substance peaks, complying with the pharmacopeial requirement, and an adequate retention time for the Pentoxifylline peak. The method was validated according to the ICH guidelines and different HPLC parameters were optimized for the determination of Pentoxifylline in its dosage form (sustained release tablets. Furthermore, the study of forced degradation of Pentoxifylline was done under various conditions including; hydrolysis (acid, alkaline and neutral, oxidation, dry heat and photo-decomposition. The proposed method could separate Pentoxifylline peak from those of the different forced degradation product peaks and the purity of the Pentoxifylline peak was confirmed using the photo-diode array detector.

  15. Adsorption studies of molasse's wastewaters on activated carbon: modelling with a new fractal kinetic equation and evaluation of kinetic models.

    Science.gov (United States)

    Figaro, S; Avril, J P; Brouers, F; Ouensanga, A; Gaspard, S

    2009-01-30

    Adsorption kinetic of molasses wastewaters after anaerobic digestion (MSWD) and melanoidin respectively on activated carbon was studied at different pH. The kinetic parameters could be determined using classical kinetic equations and a recently published fractal kinetic equation. A linear form of this equation can also be used to fit adsorption data. Even with lower correlation coefficients the fractal kinetic equation gives lower normalized standard deviation values than the pseudo-second order model generally used to fit adsorption kinetic data, indicating that the fractal kinetic model is much more accurate for describing the kinetic adsorption data than the pseudo-second order kinetic model.

  16. Crystallization Kinetics within a Generic Modeling Framework

    DEFF Research Database (Denmark)

    Meisler, Kresten Troelstrup; von Solms, Nicolas; Gernaey, Krist V.

    2014-01-01

    A new and extended version of a generic modeling framework for analysis and design of crystallization operations is presented. The new features of this framework are described, with focus on development, implementation, identification, and analysis of crystallization kinetic models. Issues related...... to the modeling of various kinetic phenomena like nucleation, growth, agglomeration, and breakage are discussed in terms of model forms, model parameters, their availability and/or estimation, and their selection and application for specific crystallization operational scenarios under study. The advantages...... of employing a well-structured model library for storage, use/reuse, and analysis of the kinetic models are highlighted. Examples illustrating the application of the modeling framework for kinetic model discrimination related to simulation of specific crystallization scenarios and for kinetic model parameter...

  17. Isolation, cytotoxicity evaluation and HPLC-quantification of the chemical constituents from Prangos pabularia.

    Directory of Open Access Journals (Sweden)

    Saleem Farooq

    Full Text Available Phytochemical analysis of the dichloromethane:methanol (1:1 extract of root parts of Prangos pabularia led to the isolation of twelve cytotoxic constituents, viz., 6-hydroxycoumarin (1, 7-hydroxycoumarin (2, heraclenol-glycoside (3, xanthotoxol (4, heraclenol (5, oxypeucedanin hydrate (6, 8-((3,3-dimethyloxiran-2-ylmethyl-7-methoxy-2H-chromen-2-one (7, oxypeucedanin hydrate monoacetate (8, xanthotoxin (9, 4-((2-hydroxy-3-methylbut-3-en-1-yloxy-7H-furo[3,2-g]chromen-7-one (10, imperatorin (11 and osthol (12. The isolates were identified using spectral techniques in the light of literature. 3-(4,5-dimethyl thiazol-2yl-2,5-diphenyltetrazolium bromide (MTT cytotoxicity screening of the isolated constituents was carried out against six human cancer cell lines including lung (A549 and NCI-H322, epidermoid carcinoma (A431, melanoma (A375, prostate (PC-3 and Colon (HCT-116 cell lines. Osthol (12 exhibited the highest cytotoxicity with IC50 values of 3.2, 6.2, 10.9, 14.5, 24.8, and 30.2 µM against epidermoid carcinoma (A431, melanoma (A375, lung (NCI-H322, lung (A549, prostate (PC-3 and colon (HCT-116 cell lines respectively. Epidermoid carcinoma cell line A431 was sensitive to most of the compounds followed by lung (A549 cancer cell line. Finally a simple and reliable HPLC method was developed (RP-HPLC-DAD and validated for the simultaneous quantification of these cytotoxic constituents in Prangos pabularia. The extract was analyzed using a reversed-phase Agilent ZORBAX eclipse plus column C18 (4.6×250 mm, 5 µm at 250 nm wavelength using a gradient water-methanol solvent system at a flow rate of 0.8 ml/min. The RP-HPLC method is validated in terms of recovery, linearity, accuracy and precision (intra and inter-day validation. This method, because of shorter analysis time, makes it valuable for the commercial quality control of Prangos pabularia extracts and its future pharmaceutical preparations.

  18. A novel fourth-order calibration method based on alternating quinquelinear decomposition algorithm for processing high performance liquid chromatography-diode array detection- kinetic-pH data of naptalam hydrolysis.

    Science.gov (United States)

    Qing, Xiang-Dong; Wu, Hai-Long; Zhang, Xi-Hua; Li, Yong; Gu, Hui-Wen; Yu, Ru-Qin

    2015-02-25

    Five-way high performance liquid chromatography-diode array detection (HPLC-DAD)-kinetic-pH data were obtained by recording the kinetic evolution of HPLC-DAD signals of samples at different pH values and a new fourth-order calibration method, alternating quinquelinear decomposition (AQQLD) based on pseudo-fully stretched matrix forms of the quinquelinear model, was developed. Simulated data were analyzed to investigate the performance of AQQLD in comparison with five-way parallel factor analysis (PARAFAC). The tested results demonstrated that AQQLD has the advantage of faster convergence rate and being insensitive to the excess component number adopted in the model. Then, they have been successfully applied to investigate quantitatively the kinetics of naptalam (NAP) hydrolysis in two practical systems. Additionally, the serious chromatographic peak shifts were accurately corrected by means of chromatographic peak alignment method based on abstract subspace difference. The good recoveries of NAP were obtained in these samples by selecting the time region of chromatogram. The elution time, spectral, kinetic time and pH profiles resolved by the chemometric techniques were in good agreement with experimental observations. It demonstrates the potential for the utilization of fourth-order data for some complex systems, opening up a new approach to fourth-order data generation and subsequent fourth-order calibration. Copyright © 2014 Elsevier B.V. All rights reserved.

  19. NEW DEFINITIONS OF KINETIC VISUAL ACUITY AND KINETIC VISUAL FIELD AND THEIR AGING EFFECTS

    Directory of Open Access Journals (Sweden)

    Jinglong WU

    2009-01-01

    However, traditional kinetic visual acuity and kinetic visual field measurements do not factor in the effects of individual differences in simple reaction times. This study identifies problems with the traditional method employed to define kinetic visual acuity and kinetic visual fields, and proposes new definitions of kinetic visual acuity and kinetic visual fields that measure simple reaction times and their aging effects. Simple reaction time tests reveal that simple reaction times of senior citizens are longer than those of younger people. The results of appraisal tests between traditional and new kinetic visual acuity definitions demonstrate the appropriateness of the new kinetic visual acuity definition. The study also takes a quantitative look at the aging effects of kinetic visual fields, measuring kinetic visual field characteristics of senior citizens while assessing space dependence, light dependence and index speed dependence of young people. The results obtained show that kinetic visual field ranges decrease with age, particularly in upward visual fields rather than downward visual fields in all target conditions. Visual field angle reductions in the temple sides of upward visual fields were of particular note.

  20. [Determination of triterpenoic acids in fruits of Ziziphus jujuba using HPLC-MS with polymeric ODS column].

    Science.gov (United States)

    Zhang, Yong; Zhou, An; Xie, Xiao-Mei

    2013-03-01

    A simple and sensitive method has been developed to simultaneously determine betunilic acid, oleanolic acid and ursolic acid in the fruits of Ziziphus jujuba from different regions by HPLC-MS. This HPLC assay was performed on PAH polymeric C18 bonded stationary phase column with mobile phase contained acetonitrile-water (90: 10) and with negative ESI detection mode. The developed approach was characterized by short time consumption for chromatographic separation, high sensitivity and good reliability so as to meet the requirements for rapid analysis of large-batch fruits of Z. jujuba from different habitats.

  1. A Comparison of Four Methods (Immunochemistry and HPLC) for Determination of 25-(OH)-Vitamin D in Postmenopausal Women.

    Science.gov (United States)

    Klapkova, Eva; Cepova, Jana; Pechova, Marta; Dunovska, Katerina; Kotaska, Karel; Prusa, Richard

    2017-02-01

    Three immunochemical methods for the determination of 25-(OH)-vitamin D and validated HPLC method for the determination of 25-(OH)-vitamin D3 and 25-(OH)-vitamin D2 were compared. 62 patient samples from postmenopausal women were measured and the results obtained by all these methods were compared. We used three chemiluminescent assays for determination of 25-(OH)-vitamin D. 25-(OH)-vitamin D3 and 25-(OH)-vitamin D2 were determined by HPLC with UV detection (Agilent 1200). The chemiluminescent assays were performed using the Abbott Architect i4000SR analyzer (Abbott Laboratories, Germany), the ADVIA Centaur (Siemens, USA), and the Liaison XL (DiaSorin Inc, USA). The statistical evaluation was done using GraphPad Prism 6.0. The data were tested by Tukey's multiple comparison test. All methods showed significant differences in comparison with the immunochemical method from DiaSorin (p < 0.001 for Abbott, p < 0.05 for Siemens, and p < 0.0001 for HPLC). The comparison of the immunochemical method from Siemens with HPLC was also significant, p < 0.05. The mean of DiaSorin measurements was 38% lower than the mean of HPLC measurements. The non-significant difference was shown by the comparison of Abbott with HPLC and also Abbott with Siemens. Means for the 25-(OH)-vitamin D methods used were: Abbott 70.2 ± 24.2 nmol/L, Siemens 67.6 ± 27.9 nmol/L, DiaSorin 53.5 ± 17.1, and HPLC 82.4 ± 40.0 nmol/L. The comparison of the DiaSorin immunochemical assay with other tested methods showed the greatest deviation. The mean of DiaSorin measurements was 38% lower than the mean of HPLC measurements. According to the results of the DiaSorin method, most patients treated with vitamin D would not achieve the optimal level of 25-(OH)-vitamin D and this could negatively affect the clinical decision.

  2. Inositol phosphates from barley low-phytate grain mutants analysed by metal-dye detection HPLC and NMR

    DEFF Research Database (Denmark)

    Hatzack, F.; Hübel, F.; Zhang, W.

    2001-01-01

    Inositolphosphates from barley low-phytate grain mutants and their parent variety were analysed by metal-dye detection HPLC and NMR. Compound assignment was carried out by comparison of retention times using a chemical hydrolysate of phytate [Ins(1,2,3,4,5,6)P(6)] as a reference; Co-inciding rete......Inositolphosphates from barley low-phytate grain mutants and their parent variety were analysed by metal-dye detection HPLC and NMR. Compound assignment was carried out by comparison of retention times using a chemical hydrolysate of phytate [Ins(1,2,3,4,5,6)P(6)] as a reference; Co...

  3. Comparative Study of RP-HPLC and UV Spectrophotometric Techniques for the Simultaneous Determination of Amoxicillin and Cloxacillin in Capsules.

    Science.gov (United States)

    Giang, Do T; Hoang, Vu D

    2010-04-01

    Reversed-phase HPLC and UV spectrophotometric techniques using water as solvent have been developed and validated for the simultaneous determination of amoxicillin and cloxacillin in capsules. For both techniques, the linearity range of 60.073x2013;140.0 µg/mL was studied. The spectrophotometric data show that non-derivative techniques, such as absorbance ratio and compensation, and ratio spectra first-order derivative could be successfully used for the co-assay of amoxicillin and cloxacillin. Based on the statistical comparison of spectrophotometric and chromatographic data, the interchangeability between HPLC and UV spectrophotometric techniques has been suggested for the routine analysis.

  4. Photocatalytic mineralization of codeine by UV-A/TiO₂--Kinetics, intermediates, and pathways.

    Science.gov (United States)

    Kuo, Chin-Sheng; Lin, Cheng-Fang; Hong, Pui-Kwan Andy

    2016-01-15

    This study investigated the photocatalytic degradation of codeine by UV-irradiated TiO2. The degradation kinetics was determined under varied conditions including the TiO2 loading, codeine concentration, and pH. Codeine and several reaction intermediates including morphine were identified and tracked during degradation using HPLC/MS-MS technique, along with TOC and IC measurements. Specifically, removal of 100 μg/L of spike codeine was complete in 3 min by contact with a 0.1 g/L suspension of TiO2 under UV irradiation at pH 7. The degradation kinetics of codeine was first-order with respect to both the catalyst TiO2 and the reactant codeine, with enhanced reaction rates with increasing pH up to pH 9. Mineralization of codeine was possible upon prolonged contact; near complete mineralization of 10 mg/L of codeine was achieved in 90 min with 0.1 g/L TiO2 under irradiation at pH 5, during which the organic nitrogen was converted to NH3-N (74%) and NO3-N (22%). Based on the identified intermediates, two degradation pathways were proposed of which one involved ipso-substitution followed by cleavage of the aromatic ring and another involved repeated hydroxylation of the codeine molecule followed by its fragmentation. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. Biosorption of Bisphenol A by Agricultural Waste: A Kinetic and Isothermic Study

    Directory of Open Access Journals (Sweden)

    Davoud Balarak

    2017-06-01

    Full Text Available B Abstract Background and Objectives: Bisphenol A is a phenolic compound, which even in low concentration, is harmful and toxic for human and environment and is abundantly found in industrial effluents. In the present study, the removal of bisphenol A by Canola wastes, was investigated. Methods: In this experimental study, first canola waste was collected and their stem was removed, and then were dried in fur (105°C for 24h and were sized using ASTM. The changes of pH, adsorbent dosage, contact time, and bisphenol A concentration, were assessed and the remaining concentration of bisphenol A was analyzed using HPLC. Equilibrium data were investigated by various types of adsorption isotherms and kinetics. Results: In this study, the specific surface area of adsorbent was 52.5m2/g. The maximum absorption of bisphenol A was obtained at pH=3, adsorbent dosage was 4g/L and contact time was 75 min. The bisphenol A removal efficiency decreased from 98.9% to 65.4% with increasing concentrations of bisphenol A from 25 to 200mg/L. Also, the results of adsorption study showed the highest correlation with the Langmuir isotherm and pseudo second-order kinetic model. Conclusion: According to the results of the current study, bisphenol adsorbent can be used as an effective and low-cost adsorbent to treat the industrial wastewater and/or aqueous solution containing phenolic compounds.

  6. Transformation of benzophenone-type UV filters by chlorine: Kinetics, products identification and toxicity assessments.

    Science.gov (United States)

    Li, Jian; Ma, Li-yun; Xu, Li

    2016-07-05

    The present study focused on the kinetics, transformation pathways and toxicity of several benzophenone-type ultraviolet filters (BPs) during the water chlorination disinfection process. The transformation kinetics of the studied three BPs was found to be second-order reaction, which was dependent on the concentration of BPs and chlorine. The second-order rate constants increased from 86.7 to 975 M(-1) s(-1) for oxybenzone, 49.6-261.7 M(-1) s(-1) for 4-hydroxybenzophenone and 51.7-540 M(-1) s(-1) for 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid with the increasing pH value from 6 to 8 of the chlorination disinfection condition. Then the transformation products (TPs) of these BPs were identified by HPLC-QTof analysis. Several transformation pathways, including electrophilic substitution, methoxyl substitution, ketone groups oxidation, hydrolysis, decarboxylation and ring cleavage reaction, were speculated to participate in the chlorination transformation process. Finally, according to the toxicity experiment on luminescent bacteria, Photobacterium phosphoreum, enhanced toxicity was observed for almost all the TPs of the studied BPs except for 2,2'-dihydroxy-4,4'-dimethoxybenzophenone; it suggested the formation of TPs with more toxic than the parent compounds during the chlorination process. The present study provided a foundation to understand the transformation of BPs during chlorination disinfection process, and was of great significance to the drinking water safety. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Effect of ultrasonic waves on the stability of all-trans lutein and its degradation kinetics.

    Science.gov (United States)

    Song, Jiang-Feng; Li, Da-Jing; Pang, Hui-Li; Liu, Chun-Quan

    2015-11-01

    Ultrasound treatment has been widely applied in the extraction of biologically active compounds including carotenoids. However, there are few reports on their effects on the stability of these compounds. In the present study, the stability of all-trans lutein, one of the carotenoids, was investigated under the action of ultrasound. Results showed that ultrasound induced the isomerization of all-trans lutein to its isomers, namely to 13-cis lutein, 13'-cis lutein, 9-cis lutein and 9'-cis lutein as analyzed by HPLC coupled with DAD and LC-MS; and the percentage of the isomerization increased with increasing both ultrasonic frequency and power. The stability of all-trans lutein in dichloromethane was worst among multiple kinds of solvents. Interestingly, the retention rate of all-trans lutein improved as the temperature increased, which runs counter to the Arrhenius law. Under ultrasound irradiation, the degradation mechanism might be different with various temperatures, the degradation of all-trans lutein followed first-order kinetics at 20°C, while second-order kinetics was followed at 30-50°C. As the ultrasonic reaction time prolonged, lutein epoxidation nearly occurred. Those results presented here emphasized that UAE techniques should be carefully used in the extraction of all-trans lutein. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. Azoreductase kinetics and gene expression in the synthetic dyes-degrading Pseudomonas

    Directory of Open Access Journals (Sweden)

    Ameer Elfarash

    2017-12-01

    Full Text Available Microorganisms have an effective capability to degrade synthetic dyestuff enzymatically. In this study, two 16S rRNA identified Pseudomonas aeruginosa bacterial isolates (ASU3 and ASU6 have been screened to enzymatically degrade both Disperse Blue 64 (DB64 and Acid Yellow 17 (AY17 which resembles 2 of the synthetic dyes that causes aquatic environmental pollution. The expression of the azoR1 gene has been detected in the strains, the degradation percentage of DB64 and AY17 by stain ASU6 was found to exceed the ASU3. This returned to the differences in the expression levels of azoR1 between the ASU6 and the ASU3 which was confirmed by RT-PCR. In addition, the specific activity (U/mg protein of azoreductase in ASU6 was higher than ASU3 when MethylRed (MR, DB64 and AY17 were used as a substrate, separately. The azoreductase kinetics was studied to find the optimum condition for maintaining the stability of the enzyme. The degraded products separated by HPLC/MS were tested for their toxicity on two crop plants and they were nontoxic to the plants. Keywords: Azoreductase, Kinetics, Pseudomonas aeruginosa, Synthetic dyes

  9. Determination of related substances in lisinopril and amlodipine tablets by HPLC

    Directory of Open Access Journals (Sweden)

    Dao-Rui Yu

    2016-06-01

    Full Text Available Objective: To establish an HPLC method for determining the related substances in lisinopril and amlodipine tablets. Methods: An Inertsil Thermo BDS HYPERSIL C18 (4.6 mm伊250 mm, 5 μm column was used with the Acetonitrile-water-phosphoric acid (10:90:0.1 as mobile phase A and Acetonitrile-water-phosphoric acid (90:10:0.1 as mobile phase B by gradient elution at the detection wavelength of 215 nm. The flow rate was 1.0 mL/min and the column temperature was 30 ℃. Results: The separation of the impurity peak and peak was good. Besides, all the impurities could be detected effectively. Conclusions: The method is sensitive, accurate and selective. It is suitable for control the related substances in lisinopril and Amlodipine tablets.

  10. RP - HPLC Method for Determination of Piperine from Piper longum Linn. and Piper nigrum Linn

    Directory of Open Access Journals (Sweden)

    M. K. Santosh

    2005-01-01

    Full Text Available Piper longum Linn. and Piper nigrum Linn. are used as spices and medicines. Quantitative determination of piperine was undertaken to provide an easy and simple analytical method, which can be used as a routine quality control method. RP-HPLC was performed using methanol and water as mobile phase. The detection and quantification was performed at a wavelength of 345 nm. Linearity of detector response for piperine was between the concentrations 0.005% to 0.1%. The correlation coefficient obtained for the linearity was 0.998. The assay value of piperine for fruit and root of P. longum was found to be 0.879% and 0.31%. The assay value of piperine for fruit of P. nigrum was 4.5%. The recovery value of standard piperine was 99.4%. Low value of standard deviation and coefficient of variation are indicative of high precision of the method.

  11. Quantitative determination of Zn protoporphyrin IX, heme and protoporphyrin IX in Parma ham by HPLC.

    Science.gov (United States)

    Wakamatsu, Jun-Ichi; Odagiri, Hiroko; Nishimura, Takanori; Hattori, Akihito

    2009-05-01

    We measured the contents of Zn protoporphyrin IX (ZPP), heme and protoporphyrin IX (PPIX) in Parma ham by simultaneous analysis using high-performance liquid chromatography (HPLC). Extraction with ethyl acetate-acetic acid (4:1) was suitable for the quantitative analysis of ZPP. The contents of heme, ZPP and PPIX in Parma ham were 15.0-29.9, 27.7-47.0 and 0.4-1.1μg/g, respectively, and total content of porphyrin was 43.7-76.6μg/g. The amount of ZPP in Parma ham was larger than that of heme, and ZPP accounted for 60-70% of all porphyrins.

  12. Uncertainty budget for final assay of a pharmaceutical product based on RP-HPLC

    DEFF Research Database (Denmark)

    Heydorn, Kaj; Anglov, Thomas; Byrialsen, Kirsten

    2003-01-01

    Compliance with specified limits for the content of active substance in a pharmaceutical drug requires knowledge of the uncertainty of the final assay. The uncertainty of measurement is based on the ISO recommendation as expressed in the Guide to the Expression of Uncertainty in Measurement (GUM......). The reported example illustrates the estimation of uncertainty for the final determination of a protein concentration by HPLC using UV detection, using the approach described by EURACHEM/CITAC. The combined standard uncertainty for a protein concentration of 2400 mumol/L was estimated to be 14 mumol/L. All...... known and potential uncertainty components are presented in Ishikawa diagrams and were carefully evaluated using Type A or Type B estimates. Special efforts were made to avoid duplication or omission of significant contributions to the combined uncertainty. Hence, before accepting the uncertainty budget...

  13. A review of post-column photochemical reaction systems coupled to electrochemical detection in HPLC

    Energy Technology Data Exchange (ETDEWEB)

    Fedorowski, Jennifer [Department of Chemistry and Biochemistry, University of Maryland, Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250 (United States); LaCourse, William R., E-mail: lacourse@umbc.edu [Department of Chemistry and Biochemistry, University of Maryland, Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250 (United States)

    2010-01-04

    Post-column photochemical reaction systems have developed into a common approach for enhancing conventional methods of detection in HPLC. Photochemical reactions as a means of 'derivatization' have a significant number of advantages over chemical reaction-based methods, and a significant effort has been demonstrated to develop an efficient photochemical reactor. When coupled to electrochemical (EC) detection, the technique allows for the sensitive and selective determination of a variety of compounds (e.g., organic nitro explosives, beta-lactam antibiotics, sulfur-containing antibiotics, pesticides and insecticides). This review will focus on developments and methods using post-column photochemical reaction systems followed by EC detection in liquid chromatography. Papers are presented in chronological order to emphasize the evolution of the approach and continued importance of the application.

  14. HPLC for confirmatory diagnosis and biochemical monitoring of Cuban patients with hyperphenylalaninemias.

    Science.gov (United States)

    Contreras, Jiovanna; Alonso, Elsa; Fuentes, Lisset E

    2015-01-01

    Hyperphenylalaninemias are inborn errors of phenylalanine metabolism caused by deficiency of L-phenylalanine hydroxylase (the enzyme that converts phenylalanine to tyrosine), resulting in increased serum phenylalanine (>4 mg/dL or 240 µmol/L). Phenylketonuria, or PKU, is the most common form. Untreated PKU is associated with progressive neurodevelopmental delay, evolving towards intellectual impairment. Cuba introduced a national newborn screening program for PKU in 1986. It has enabled early diagnosis and initiation of dietary treatment, reducing appearance of intellectual impairment in these patients. Originally, confirmatory diagnosis was done only by quantifying serum phenylalanine. In 2010, however, an HPLC method for quantifying serum phenylalanine and tyrosine simultaneously was validated at the National Medical Genetics Center, to perform confirmatory and differential diagnosis of hyperphenylalaninemias, as well as biochemical monitoring of patients diagnosed. Describe experience using HPLC confirmatory diagnosis for positive cases from the National Neonatal Screening Program for Phenylketonuria and in biochemical monitoring of diagnosed patients after initiation of dietary treatment. A descriptive retrospective case-series study was conducted from June 2010 through June 2012. The study population comprised 531 infants who tested positive in the National Neonatal Screening Program for Phenylketonuria. Variables used were serum phenylalanine concentration (first criterion of positivity) and tyrosine, phenylalanine/tyrosine ratio (second criterion, both detected by reverse-phase HPLC with direct fluorescence), hyperphenylalaninemia classification, year of diagnosis, sex, and province of origin. Of the samples, 97.7% (519/531) were confirmed as false positives, and 10.4% (55/531) had transient neonatal tyrosinemia. Hyperphenylalaninemia was diagnosed in 12 infants (2.2%): 1.3% (7/531) presented classical PKU, with 34.7 ± 14.7 mg/dL phenylalanine in serum and

  15. HPLC Fingerprinting of Sennosides in Laxative Drugs with Isolation of Standard Substances from Some Senna Leaves

    Directory of Open Access Journals (Sweden)

    L. Omur Demirezer

    2011-01-01

    Full Text Available Senna leaves are one of the oldest medicinal herbs and they are used as laxative. Herbal teas which contain senna leaves are most commonly used to promote weight loss. The quality control of slimming teas which contain Senna leaves and also pharmaceutical preparations including Senna extract enriched by sennoside B was achieved by HPLC fingerprinting method. While the presence of sennoside A and B in laxative drugs was proved, it was seen to be devoid of sennosides in slimming teas. Kaempferol 3-O-β-D-gentiobioside (1, aloe-emodine 8-O-β-D-glucopyranoside (2, rhein 8-O-β-D-glucopyranoside (3, torachrysone 8-O-β-D-glucopyranoside (4, isorhamnetine 3-O-β-D-gentiobioside (5 were also isolated from Senna leaves.

  16. Rapid HPLC method for the simultaneous monitoring of duloxetine, venlaflaxine, fluoxetine and paroxetine in biofluids.

    Science.gov (United States)

    Samanidou, Victoria F; Kourti, Paraskevi V

    2009-08-01

    A simple and rapid HPLC method is developed for the determination of two serotonin-norepinephrine-reuptake inhibitors (duloxetine and venlaflaxine) and two selective serotonin-reuptake inhibitors (fluoxetine and paroxetine) in human biofluids. Separation was performed on an Inertsil ODS-3 column (250 x 4.0 mm, 5 µm) with acetonitrile-ammonium acetate (0.05 M, 41:59 v/v) at 235 nm, within 7 min. SPE on Oasis(®) HLB cartridges was applied for the isolation of analytes from biofluids. The developed methodology was validated in terms of sensitivity, linearity, accuracy, precision, stability and selectivity. Relative standard deviation was less than 10.4%. Limit of detection was 0.2-0.6 ng/µl in blood plasma and 0.1-0.8 ng/µl in urine. The method was successfully applied to biofluids from a patient under duloxetine treatment.

  17. Development and Application of Multidimensional HPLC Mapping Method for O-linked Oligosaccharides

    Directory of Open Access Journals (Sweden)

    Koichi Kato

    2011-12-01

    Full Text Available Glycosylation improves the solubility and stability of proteins, contributes to the structural integrity of protein functional sites, and mediates biomolecular recognition events involved in cell-cell communications and viral infections. The first step toward understanding the molecular mechanisms underlying these carbohydrate functionalities is a detailed characterization of glycan structures. Recently developed glycomic approaches have enabled comprehensive analyses of N-glycosylation profiles in a quantitative manner. However, there are only a few reports describing detailed O-glycosylation profiles primarily because of the lack of a widespread standard method to identify O-glycan structures. Here, we developed an HPLC mapping method for detailed identification of O-glycans including neutral, sialylated, and sulfated oligosaccharides. Furthermore, using this method, we were able to quantitatively identify isomeric products from an in vitro reaction catalyzed by N-acetylglucosamine-6O-sulfotransferases and obtain O-glycosylation profiles of serum IgA as a model glycoprotein.

  18. Determination of Diphenylamine in Gunshot Residue by HPLC-MS/MS

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    Hongcheng Mei

    2016-01-01

    Full Text Available A high performance liquid chromatography tandem mass spectrometry/mass spectrometry (HPLC-MS/MS protocol was developed for the determination of diphenylamine (DPA. Four productions of DPA were selected for qualitative assay and the peak area of the main product ion for quantitation. By means of separation using an Agilent Extend-C18 column (CA, USA (150 mm × 4.6 mm, 5 μm with methanol-water (90:10 as the mobile phase, DPA was detected by electrospray ionization (ESI tandem mass spectrometry in positive mode. The linearity of the peak area versus concentration ranged 5-500 ng/mL, r 2 = 0.9978. The limit of detection (S/N =3 of this method was 0.3 ng/mL. This method is applicable for the determination of DPA in gunshot residue.

  19. HPLC Enantioseparation of Phenylcarbamic Acid Derivatives by Using Macrocyclic Chiral Stationary Phases

    Directory of Open Access Journals (Sweden)

    Hroboňová Katarína

    2016-06-01

    Full Text Available The HPLC by using chiral stationary phases based on macrocyclic antibiotics, dimethylphenyl carbamate cyklofructan 7 and β-cyclodextrin in terms of polar-organic separation mode (mobile phase methanol/acetonitrile/acetic acid/triethylamine were used for enantioseparation of alkoxy derivatives of phenylcarbamic acid. The effect of the analyte structures on the efficiency of enantioseparation was investigated. The most suitable stationary phase was teicoplanin aglycone, where the separations of the enantiomers were obtained (the resolution value from 0.65 to 2.90, depending on the structure of the analyte. Significant effect on the resolution of the enantiomers has position of alkoxy substituent in the hydrophobic part of the molecule. The enantiorecognition was achieved for 3-alkoxysubstituted derivatives.

  20. Application of artificial neural networks for response surface modelling in HPLC method development

    Directory of Open Access Journals (Sweden)

    Mohamed A. Korany

    2012-01-01

    Full Text Available This paper discusses the usefulness of artificial neural networks (ANNs for response surface modelling in HPLC method development. In this study, the combined effect of pH and mobile phase composition on the reversed-phase liquid chromatographic behaviour of a mixture of salbutamol (SAL and guaiphenesin (GUA, combination I, and a mixture of ascorbic acid (ASC, paracetamol (PAR and guaiphenesin (GUA, combination II, was investigated. The results were compared with those produced using multiple regression (REG analysis. To examine the respective predictive power of the regression model and the neural network model, experimental and predicted response factor values, mean of squares error (MSE, average error percentage (Er%, and coefficients of correlation (r were compared. It was clear that the best networks were able to predict the experimental responses more accurately than the multiple regression analysis.