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Sample records for high-performance liquid chromatography-ultraviolet

  1. High-performance liquid chromatography ultraviolet-photodiode array detection method for aflatoxin B1 in cattle feed supplements

    Science.gov (United States)

    Mochamad, Lazuardi; Hermanto, Bambang

    2017-01-01

    Aim: The objective of the current study is to determine the concentration of aflatoxin B1 using high-performance liquid chromatography (HPLC) with a photodiode array (PDA) detector. Materials and Methods: Aflatoxin B1 certified reference grade from Trilogy Analytical Laboratory dissolved acetonitrile (ACN) at 10 µg/mL was using standard assessment. HPLC instruments such as ultraviolet-PDA detector used a Shimadzu LC-6AD pump with DGU-20A5 degasser, communication module-20A, and PDA detector SPD-M20A with FRC-10A fraction collector. The HPLC was set isocratic method at 354 nm with a reverse-phase ODS C18 column (LiChrospher® 100 RP-18; diameter, 5 µm) under a 20°C controlled column chamber. Rheodyne® sample loops were performed in 20 µL capacities. The mobile phase was performed at fraction 63:26:11 H2O: methanol:ACN at pH 6.8. A total of 1 kg of feed contained 10% bread crumbs and 30% concentrated, 40% forage, and 20% soybean dregs were using commercials samples. Samples were extracted by ACN and separated with solid phase extraction ODS 1 mL than elution with mobile phase to collect at drying samples performed. The samples were ready to use after added 1 mL mobile phase than injected into the system of HPLC. Results: We found that the retention time of aflatoxin B1 was approximately 10.858 min. Linearity of 0.01-0.08 µg/mL aflatoxin B1 dissolved in mobile phase was obtained at R2=0.9. These results demonstrate that these methods can be used to analyze aflatoxin B1 and gain 89-99% recovery. The limit of detection of this assay was obtained at 3.5 × 10−6 µg/mL. Conclusion: This method was easy to apply and suitable to analyzing at small concentrations of aflatoxin B1 in formulated product of feed cattle. PMID:28919686

  2. High-performance liquid chromatography ultraviolet-photodiode array detection method for aflatoxin B1 in cattle feed supplements.

    Science.gov (United States)

    Mochamad, Lazuardi; Hermanto, Bambang

    2017-08-01

    The objective of the current study is to determine the concentration of aflatoxin B1 using high-performance liquid chromatography (HPLC) with a photodiode array (PDA) detector. Aflatoxin B1 certified reference grade from Trilogy Analytical Laboratory dissolved acetonitrile (ACN) at 10 µg/mL was using standard assessment. HPLC instruments such as ultraviolet-PDA detector used a Shimadzu LC-6AD pump with DGU-20A5 degasser, communication module-20A, and PDA detector SPD-M20A with FRC-10A fraction collector. The HPLC was set isocratic method at 354 nm with a reverse-phase ODS C18 column (LiChrospher(®) 100 RP-18; diameter, 5 µm) under a 20°C controlled column chamber. Rheodyne(®) sample loops were performed in 20 µL capacities. The mobile phase was performed at fraction 63:26:11 H2O: methanol:ACN at pH 6.8. A total of 1 kg of feed contained 10% bread crumbs and 30% concentrated, 40% forage, and 20% soybean dregs were using commercials samples. Samples were extracted by ACN and separated with solid phase extraction ODS 1 mL than elution with mobile phase to collect at drying samples performed. The samples were ready to use after added 1 mL mobile phase than injected into the system of HPLC. We found that the retention time of aflatoxin B1 was approximately 10.858 min. Linearity of 0.01-0.08 µg/mL aflatoxin B1 dissolved in mobile phase was obtained at R(2)=0.9. These results demonstrate that these methods can be used to analyze aflatoxin B1 and gain 89-99% recovery. The limit of detection of this assay was obtained at 3.5 × 10(-6) µg/mL. This method was easy to apply and suitable to analyzing at small concentrations of aflatoxin B1 in formulated product of feed cattle.

  3. The Measurement of Meloxicam and Meloxicam Metabolites in Rat Plasma Using a High-Performance Liquid Chromatography-Ultraviolet Spectrophotometry Method.

    Science.gov (United States)

    Miyamoto, Aoi; Aoyama, Takahiko; Matsumoto, Yoshiaki

    2017-02-01

    A high-performance liquid chromatography-ultraviolet spectrophotometry (HPLC-UV) method for the determination of meloxicam (MEL) and meloxicam metabolites (5'-hydroxy meloxicam (5-HMEL) and 5'-carboxy meloxicam (5-CMEL)) has been developed. After extraction of MEL, 5-HMEL, and 5-CMEL from rat plasma using Oasis HLB cartridges, the extracts were separated with a Luna C18 (2) 100 A column (5 µm, 4.6×150 mm, Phenomenex) using a mobile phase of 50 mM phosphate buffer (pH 2.15, solvent A) and acetonitrile (solvent B) at a flow rate of 0.8 mL/min in a linear gradient. The detection wavelength was 360 nm, and the internal standard (IS) was piroxicam. Each calibration curve was linear in the range of 40 to 1000 ng/mL (r2>0.999). The extraction rates of MEL, 5-HMEL, and 5-CMEL were greater than 86.9%. The intra- and inter-day accuracies were in the range of 95.0 to 119.0%, and the precision was 0.2 to 17.0%. To the best of our knowledge, this is the first report of the quantitative and qualitative measurement of meloxicam and each metabolite using an HPLC-UV method.

  4. On-line high-performance liquid chromatography-ultraviolet-nuclear magnetic resonance method of the markers of nerve agents for verification of the Chemical Weapons Convention.

    Science.gov (United States)

    Mazumder, Avik; Gupta, Hemendra K; Garg, Prabhat; Jain, Rajeev; Dubey, Devendra K

    2009-07-03

    This paper details an on-flow liquid chromatography-ultraviolet-nuclear magnetic resonance (LC-UV-NMR) method for the retrospective detection and identification of alkyl alkylphosphonic acids (AAPAs) and alkylphosphonic acids (APAs), the markers of the toxic nerve agents for verification of the Chemical Weapons Convention (CWC). Initially, the LC-UV-NMR parameters were optimized for benzyl derivatives of the APAs and AAPAs. The optimized parameters include stationary phase C(18), mobile phase methanol:water 78:22 (v/v), UV detection at 268nm and (1)H NMR acquisition conditions. The protocol described herein allowed the detection of analytes through acquisition of high quality NMR spectra from the aqueous solution of the APAs and AAPAs with high concentrations of interfering background chemicals which have been removed by preceding sample preparation. The reported standard deviation for the quantification is related to the UV detector which showed relative standard deviations (RSDs) for quantification within +/-1.1%, while lower limit of detection upto 16mug (in mug absolute) for the NMR detector. Finally the developed LC-UV-NMR method was applied to identify the APAs and AAPAs in real water samples, consequent to solid phase extraction and derivatization. The method is fast (total experiment time approximately 2h), sensitive, rugged and efficient.

  5. Screening, recognition and quantitation of salbutamol residues in ham sausages by molecularly imprinted solid phase extraction coupled with high-performance liquid chromatography-ultraviolet detection.

    Science.gov (United States)

    Yan, Hongyuan; Wang, Ruiling; Han, Yehong; Liu, Suting

    2012-07-01

    A highly selective molecularly imprinted solid phase extraction (MISPE) coupled with liquid chromatography-ultraviolet detection was developed for the determination of salbutamol (SAL) in ham sausages. New molecularly imprinted polymers (MIPs) were synthesized with phenylephrine as dummy template and it revealed good affinity to SAL in methanol-acetonitrile system. Adsorption capacity of the MIPs was evaluated by dynamic adsorption experiments. The MIPs were used as SPE sorbent for the selective clean-up and pre-concentration of SAL in ham sausage samples. The results showed that the matrix compounds presented in ham sausage samples could be removed effectively and the recoveries of SAL at three spiked levels were ranged from 82.6 to 100.5% with the relative standard deviation (RSD) of less than 3.6%. This method is simple and sensitive, and is therefore an alternative tool to the existing methods for analyzing residual SAL in biological samples. Copyright © 2012 Elsevier B.V. All rights reserved.

  6. Development of high performance liquid chromatography-ultraviolet detection method for screening mebendazole, clorsulon, diaveridine, and tolfenamic acid in animal-based food samples.

    Science.gov (United States)

    Kang, Yun Pyo; Yu, Jin; Huh, Yoonyoung; Oh, Jae Ho; Kwon, Chan Hyeok; Lee, Seul Ji; Ee, Ji Won; Kim, Geun Tae; Lee, Jin Gyun; Lee, Jeongmi; Park, Jeong Hill; Kim, You-Sun; Kwon, Sung Won

    2014-03-01

    This study focused on the detection and validation of the residues of the four veterinary drugs, mebendazole, clorsulon, diaveridine, and tolfenamic acid, using high performance liquid chromatography (HPLC) and an ultraviolet (UV) detector. Utilizing C18 column as a stationary phase and applying appropriate mobile phases to each analysis according to the properties of the analytes, target compounds in food samples were successfully detected and separated within 15-50 min. Additionally, in order to optimize detection, liquid-liquid extraction (LLE) and purification steps were established to minimize the endogenous peaks and their interferences. The method was validated through testing of linearity, accuracy, precision, the limit of detection (LOD) and the limit of quantification (LOQ). The LOQ levels of the four drugs were lower than the maximum residual limit, and the coefficient of determination (R(2) ) was over 0.99. The recovery results ranged from 82.3-105.2%, 79.3-83.3%, 79.4-86.0%, and 81.7-88.5% with relative standard deviations lower than 20% for mebendazole, clorsulon, diaveridine, and tolfenamic acid, respectively, corresponding to the CODEX guideline. This proposed method reduces costs and enables easier application in rural or remote areas where testing facilities or instruments often are unavailable. Copyright © 2013 John Wiley & Sons, Ltd.

  7. High-performance liquid chromatography-ultraviolet detection method for the simultaneous determination of typical biogenic amines and precursor amino acids. Applications in food chemistry.

    Science.gov (United States)

    Mazzucco, Eleonora; Gosetti, Fabio; Bobba, Marco; Marengo, Emilio; Robotti, Elisa; Gennaro, Maria Carla

    2010-01-13

    A reversed-phase high-performance liquid chromatography (HPLC) method was developed for the simultaneous determination in food of biogenic amines and their precursor amino acids after a precolumn derivatization with dansyl chloride. The chromatographic conditions, selected to be suitable for mass spectrometry detection, were optimized through experimental design and artificial neural networks. The HPLC-UV method was validated by comparing the separation results with those obtained through a HPLC method, working under the same chromatographic conditions but employing mass spectrometry detection. The HPLC-UV method was then applied to the analysis of different food samples, namely, cheese, clams, salami, and beer. For all of the matrices, recoveries (relative standard deviation always 92% were obtained. The results are discussed as a function of the total biogenic amine content and of the concentration ratio between amines and precursor amino acids.

  8. Rapid quantitation of fluoxetine and norfluoxetine in serum by micro-disc solid-phase extraction with high-performance liquid chromatography-ultraviolet absorbance detection.

    Science.gov (United States)

    Li, Kong M; Thompson, Murray R; McGregor, Iain S

    2004-05-25

    A rapid, robust and sensitive method for the extraction and quantitative analysis of serum fluoxetine (FLX) and norfluoxetine (N-FLX) using a solid-phase extraction (SPE) column and high-performance liquid chromatography (HPLC) with ultraviolet (UV) detection was developed and validated. The sample clean-up step was performed by simple micro-disc mixed-mode (non-polar and strong cation exchange (SCX)) SPE cartridges. Separation of analytes and internal standard (IS) clomipramine (CLO) from endogenous matrix interference was achieved using a Waters Symmetry C(8) (150 mm x 2.1 mm i.d., 5 microm) reversed-phase narrow bore column. The relative retention times were 8.5, 9.6 and 10.5 min for FLX, N-FLX and CLO, respectively with a low isocratic flow rate of 0.3 ml/min. Chromatographic run time was completed in 15 min and peak area ratios of analytes to IS were used for regression analysis of the calibration curve. The latter was linear from 10 to 4000 nmol/l using 0.5 ml sample volume of serum. The average recovery was 95.5% for FLX and 96.9% for N-FLX. The lowest limit of quantitation (LLOQ) for serum FLX and N-FLX was 10 nmol/l (on-column amount of 200 fmol). The method described was used to analyse serum samples obtained from rats given chronic FLX treatment and to examine the relationship between steady state serum drug concentrations and neurochemical changes in several brain regions.

  9. One-pot synthesis of zeolitic imidazolate framework-8/poly (methyl methacrylate-ethyleneglycol dimethacrylate) monolith coating for stir bar sorptive extraction of phytohormones from fruit samples followed by high performance liquid chromatography-ultraviolet detection.

    Science.gov (United States)

    You, Linna; He, Man; Chen, Beibei; Hu, Bin

    2017-11-17

    In this work, zeolitic imidazolate framework-8 (ZIF-8)/poly (methyl methacrylate-ethyleneglycol dimethacrylate) (MMA-EGDMA) composite monolith was in situ synthesized on stir bar by one-pot polymerization. Compared with the neat monolith, ZIF-8/poly(MMA-EGDMA) composite monolith has larger surface area and pore volume. It also exhibits higher extraction efficiency for target phytohormones than poly(MMA-EGDMA) monolith and commercial polyethylene glycol (PEG) coated stir bar. Based on it, a method of ZIF-8/poly(MMA-EGDMA) monolith coated stir bar sorptive extraction (SBSE)-high performance liquid chromatography-ultraviolet detection (HPLC-UV) was established for the analysis of five phytohormones in apple and pear samples. The developed method exhibited low limits of detection (0.11-0.51μg/L), wide linear range (0.5-500μg/L) and good recoveries (82.7-111%), which demonstrated good application potential of the ZIF-8/monolith coated stir bar in trace analysis of organic compounds. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Application of bamboo charcoal as solid-phase extraction adsorbent for the determination of atrazine and simazine in environmental water samples by high-performance liquid chromatography-ultraviolet detector.

    Science.gov (United States)

    Zhao, Ru-Song; Yuan, Jin-Peng; Jiang, Ting; Shi, Jun-Bo; Cheng, Chuan-Ge

    2008-08-15

    In this article, a new method for the determination of triazine herbicides atrazine and simazine in environment aqueous samples was developed. It was based on solid-phase extraction (SPE) using bamboo charcoal as adsorbent and high-performance liquid chromatography-ultraviolet detector (HPLC-UV) for the enrichment and determination of atrazine and simazine at trace level. Related important factors influencing the extraction efficiency, such as the kind of eluent and its volume, flow rate of the sample, pH of the sample, and volume of the sample, were investigated and optimized in detail. Under the optimal conditions, the experimental results showed that excellent linearity was obtained over the range of 0.5-30 microg L(-1) with correlation coefficients 0.9991 and 0.9982, for atrazine and simazine, respectively; and the relative standard deviations of two analytes were 8.3, 8.7%, respectively. The proposed method was successfully applied to the analysis of tap water and well water samples. And satisfactory spiked recoveries were obtained in the range of 75.2-107.1%. The above results indicated that the developed method was an excellent alternative for the routine analysis in environmental field.

  11. Reversed-phase high-performance Liquid Chromatography-ultraviolet Photodiode Array Detector Validated Simultaneous Quantification of six Bioactive Phenolic Acids in Roscoea purpurea Tubers and their In vitro Cytotoxic Potential against Various Cell Lines

    Science.gov (United States)

    Srivastava, Sharad; Misra, Ankita; Kumar, Dharmesh; Srivastava, Amit; Sood, Anil; Rawat, AKS

    2015-01-01

    Background: Roscoea purpurea or Roscoea procera Wall. (Zingiberaceae) is traditionally used for nutrition and in the treatment of various ailments. Objective: Simultaneous reversed-phase high-performance liquid chromatography-ultraviolet (RP-HPLC) photodiode array detector identification of phenolic acids (PA's) was carried out in whole extract of tuber and their cytotoxic potential was estimated along with radical scavenging action. Bioactivity guided fractionation was also done to check the response potential against the same assay. Materials and Methods: Identification and method validation was performed on RP-HPLC column and in vitro assays were used for bioactivity. Results: Protocatechuic acid, syringic acid, ferulic acid, rutin, apigenin, and kaempferol were quantified as 0.774%, 0.064%, 0.265%, 1.125%, 0.128%, and 0.528%, respectively. Validated method for simultaneous determination of PA's was found to be accurate, reproducible, and linearity was observed between peak area response and concentration. Recovery of identified PA's was within the acceptable limit of 97.40–104.05%. Significant pharmacological response was observed in whole extract against in vitro cytotoxic assay, that is, Sulforhodamine B assay, however, fractionation results in decreased action potential. Similar pattern of results were observed in the antioxidant assay, as total phenolic content and total flavonoid content were highest in whole extract and decreases with fractionation. Radical scavenging activity was prominent in chloroform fraction, exhibiting IC50 at 0.25 mg/mL. Conclusion: Study, thus, reveals that R. purpurea exhibit significant efficacy in cytotoxic activity with the potentiality of scavenging free radicals due the presence of PA's as reported through RP-HPLC. SUMMARY Proto-catechuic acid, syringic acid, ferulic acid, rutin, apigenin and kaempferol were quantified as 0.774, 0.064, 0.265, 1.125, 0.128 and 0.528 %Preliminary cytotoxic activity revealed that whole

  12. Low-density solvent-based dispersive liquid-liquid microextraction combined with single-drop microextraction for the fast determination of chlorophenols in environmental water samples by high performance liquid chromatography-ultraviolet detection.

    Science.gov (United States)

    Li, Xiaoyi; Xue, Aifang; Chen, Hao; Li, Shengqing

    2013-03-08

    A new format of fast three-phase microextraction by combining low-density solvent-based dispersive liquid-liquid microextraction (DLLME) and single-drop microextraction (SDME) was for the first time developed for the determination of chlorophenols in environmental water samples. The extraction procedure includes a 2 min DLLME pre-extraction and a 10 min SDME back-extraction. A portion of low-density solvent (toluene) was used as organic phase and injected into the aqueous sample (donor phase) with methanol as disperser. The analytes were pre-extracted into the organic phase within 2 min. A thin layer of the organic phase formed on the top of the aqueous phase by a 2 min centrifugation. Then a drop of acceptor solution was introduced into the upper layer and SDME was carried out for the back-extraction. The stirring step typically involved in SDME and LLLME is avoided with the benefit of the high speed and efficiency of DLLME pre-extraction. After extraction, the acceptor drop was withdrawn and directly injected into a high performance liquid chromatography instrument with ultraviolet detection for analysis. Five chlorophenols, 4-chlorophenol, 2-chlorophenol, 2,4-dichlorophenol, 2,4,6-trichlorophenol, and pentachlorophenol, were selected as model compounds for developing and evaluating the method. Factors affecting extraction efficiency were studied, including the organic solvent, the disperser solvent, the composition of donor phase and acceptor phase, the volume of acceptor microdrop, and the extraction time. At optimal conditions, the method showed low detection limit (0.016-0.084 μg/L) for the five chlorophenols, good linearity (from 0.2-250 to 1.0-250 μg/L, depending on the analytes) and repeatability (RSD below 8.2, n=5). The simple, fast, and efficient feature of the proposed method was demonstrated by the analysis of chlorophenols in environmental water samples. Copyright © 2013 Elsevier B.V. All rights reserved.

  13. Comparison of dual solvent-stir bars microextraction and U-shaped hollow fiber-liquid phase microextraction for the analysis of Sudan dyes in food samples by high-performance liquid chromatography-ultraviolet/mass spectrometry.

    Science.gov (United States)

    Yu, Chunhe; Liu, Qing; Lan, Lidan; Hu, Bin

    2008-04-25

    Two sample preparation methods, dual solvent-stir bars microextraction (DSSBME) and U-shaped hollow fiber-liquid phase microextraction (U-shaped HF-LPME), are proposed and critically compared for high-performance liquid chromatography (HPLC)-ultraviolet (UV)/mass spectrometry (MS) analysis of Sudan dyes in this paper. In DSSBME, the organic solvent was confined to a pair of hollow fiber membrane fixed on a stir bar, which can stir by itself, while the hollow fiber in U-shaped HF-LPME was fixed by two microsyringes. The significant factors affecting the microextraction of Sudan dyes in both microextraction techniques have been examined and no obvious difference in the effect of extraction solvent, pH and salt concentration on the extraction efficiency of Sudan dyes was observed except extraction time and stirring speed. Both microextraction techniques were similar in terms of analytical performance from aqueous solutions (LODs ranged from 0.09 to 0.95 microgL(-1) by HPLC-UV and 2.5-6.2 microgL(-1) by HPLC-MS; the absolute LODs ranged from 0.9 to 11.25 pg by HPLC-UV and 5-21.2 pg by HPLC-MS), however, DSSBME was more stable (lower stirring speed required), less sample consuming and much shorter time required to reach extraction equilibrium; while U-shaped HF-LPME was easier to operate and no more special device required. The two microextraction techniques combined with HPLC-UV/MS were successfully applied to the analysis of real samples including strawberry sauce, capsicum oil, salted egg, and two kinds of chilli sauce. Although the LODs of HPLC-UV are lower than that of HPLC-MS by a factor of 10 in this work, the absolute LODs for both HPLC-UV and HPLC-MS are comparable. HPLC-UV cannot identify the suspicious peaks at the same retention time as that of Sudan II and III in salted egg, while HPLC-MS can give exact information of Sudan I-IV in real sample analysis and is more reliable. The sensitivity of HPLC-MS is enough for real sample analysis.

  14. High Performance Liquid Chromatography

    Science.gov (United States)

    Talcott, Stephen

    High performance liquid chromatography (HPLC) has many applications in food chemistry. Food components that have been analyzed with HPLC include organic acids, vitamins, amino acids, sugars, nitrosamines, certain pesticides, metabolites, fatty acids, aflatoxins, pigments, and certain food additives. Unlike gas chromatography, it is not necessary for the compound being analyzed to be volatile. It is necessary, however, for the compounds to have some solubility in the mobile phase. It is important that the solubilized samples for injection be free from all particulate matter, so centrifugation and filtration are common procedures. Also, solid-phase extraction is used commonly in sample preparation to remove interfering compounds from the sample matrix prior to HPLC analysis.

  15. Screening Non-colored Phenolics in Red Wines using Liquid Chromatography/Ultraviolet and Mass Spectrometry/Mass Spectrometry Libraries

    Directory of Open Access Journals (Sweden)

    Jianping Sun

    2007-03-01

    Full Text Available Liquid chromatography/ultraviolet (LC/UV and mass spectrometry/mass spectrometry (MS/MS libraries containing 39 phenolic compounds were established by coupling a LC and an ion trap MS with an electrospray ionization (ESI source, operated in negative ion mode. As a result, the deprotonated [M-H]- molecule was observed for all the analyzed compounds. Using MS/MS hydroxybenzoic acid and hydroxycinnamic acids showed a loss of CO2 and production of a [M-H-44] - fragment and as expected, the UV spectra of these two compounds were affected by their chemical structures. For flavonol and flavonol glycosides, the spectra of their glycosides and aglycones produced deprotonated [M-H]- and [A-H]- species, respectively, and their UV spectra each presented two major absorption peaks. The UV spectra and MS/MS data of flavan-3-ols and stilbenes were also investigated. Using the optimized LC/MS/MS analytical conditions, the phenolic extracts from six representative wine samples were analyzed and 31 phenolic compounds were detected, 26 of which were identified by searching the LC/UV and MS/MS libraries. Finally, the presence of phenolic compounds was confirmed in different wine samples using the LC/UV and LC/MS/MS libraries.

  16. Validation of a liquid chromatography ultraviolet method for determination of herbicide diuron and its metabolites in soil samples

    Directory of Open Access Journals (Sweden)

    ANA LUCIA S.M. FELICIO

    2016-01-01

    Full Text Available ABSTRACT Diuron is one of the most widely herbicide used worldwide, which can undergo degradation producing three primary metabolites: 3,4-dichlorophenylurea, 3-(3,4-dichlorophenyl-1-methylurea, and 3,4-dichloroaniline. Since the persistence of diuron and its by-products in ecosystems involves risk of toxicity to environment and human health, a reliable quantitative method for simultaneous monitoring of these compounds is required. Hence, a simple method without preconcentration step was validated for quantitation of diuron and its main metabolites by high performance liquid chromatography with ultraviolet detection. Separation was achieved in less than 11 minutes using a C18 column, mobile phase composed of acetonitrile and water (45:55 v/v at 0.86 mL min-1 and detection at 254 nm. The validated method using solid-liquid extraction followed by an isocratic chromatographic elution proved to be specific, precise and linear (R2 ˃ 0.99, presenting more than 90% of recovery. The method was successfully applied to quantify diuron and their by-products in soil samples collected in a sugarcane cultivation area, focusing on the environmental control.

  17. Two dimensional liquid chromatography-ultraviolet/mass spectrometric (2DLC-UV/MS) analyses for quantitation of intact proteins in complex biological matrices.

    Science.gov (United States)

    Julka, Samir; Folkenroth, Jason; Young, Scott A

    2011-07-15

    A conventional scale online two dimensional liquid chromatography-ultraviolet/mass spectrometric (2DLC-UV/MS) method was developed for simultaneous quantitation of intact proteins. A series of valve switches were utilized between the two LC dimensions and the mass spectrometer to resolve and confirm the proteins of interest from a complex biological matrix. Two model proteins, myoglobin and serum albumin were simultaneously resolved and quantitated from Escherichia coli lysate using a strong anion-exchange chromatography and reversed-phase chromatography as the first and second dimension respectively. The method validation consisted of evaluating linearity, precision, and accuracy. A linear relationship (R(2)>0.99) between the concentrations of the two proteins and peak areas was observed over the concentration range; 12.0-120.4 μg/mL and 8.5-85.4 μg/mL for serum albumin and myoglobin, respectively. The average RSD of peak areas for intra-day and inter-day analyses were 5.9% and 9.4% for myoglobin and 6.2% and 10.1% for serum albumin respectively. Over the linear range, the recoveries ranged from -15.4 to 9.0% for serum albumin and -2.5 to 9.4% for myoglobin. The system presented in this work is amenable to a quality control environment for evaluation and quantitation of expression levels of multiple target proteins. To our knowledge, this represents the first 2DLC-UV/MS method depicting the viability of simultaneous quantitation of more than one intact protein from complex biological mixtures in a single run. Copyright © 2011 Elsevier B.V. All rights reserved.

  18. High Performance Liquid Chromatography Method for the ...

    African Journals Online (AJOL)

    High Performance Liquid Chromatography Method for the Determination of Anethole in Rat Plasma. ... Journal Home > Vol 13, No 5 (2014) > ... Results: GC determination showed that anethole in the essential oil of star anise exhibited a ...

  19. Optimization and validation of high performance liquid ...

    African Journals Online (AJOL)

    Optimization and validation of high performance liquid chromatography-ultra violet method for quantitation of metoprolol in rabbit plasma: application to ... Methods: Mobile phase of methanol and 50 mM ammonium dihydrogen phosphate solution (50:50) at pH 3.05 was used for separation of metoprolol on BDS hypersil ...

  20. Gradient High Performance Liquid Chromatography Method ...

    African Journals Online (AJOL)

    Purpose: To develop a gradient high performance liquid chromatography (HPLC) method for the simultaneous determination of phenylephrine (PHE) and ibuprofen (IBU) in solid dosage form. Methods: HPLC determination was carried out on an Agilent XDB C-18 column (4.6 x 150mm, 5 μ particle size) with a gradient ...

  1. High Performance Liquid Chromatographic Determination of ...

    African Journals Online (AJOL)

    Purpose: To develop a simple, precise and rapid high-performance liquid chromatographic technique coupled with photodiode array detection (DAD) method for the simultaneous determination of rutin, quercetin, luteolin, genistein, galangin and curcumin in propolis. Methods: Ultrasound-assisted extraction was applied to ...

  2. Rapid high performance liquid chromatographic determination of ...

    African Journals Online (AJOL)

    Rapid high performance liquid chromatographic determination of chlorpropamide in human plasma. MTB Odunola, IS Enemali, M Garba, OO Obodozie. Abstract. Samples were extracted with dichloromethane and the organic layer evaporated to dryness. The residue was dissolved in methanol, and 25 ìl aliquot injected ...

  3. Determination of imatinib plasma levels in patients with chronic myeloid leukemia by high performance liquid chromatography-ultraviolet detection and liquid chromatography-tandem mass spectrometry: methods' comparison.

    Science.gov (United States)

    Awidi, Abdalla; Salem, Isam I; Najib, Naji; Mefleh, Razan; Tarawneh, Bothainah

    2010-06-01

    The aims of this study were to validate and compare HPLC and LCMSMS analytical methods and their applicability for the quantitation of imatinib in human plasma. A total of 50 patients with chronic myeloid leukemia (CML) in chronic phase (CP) receiving 400 mg/day imatinib were enrolled in the study. Drug levels were determined by HPLC-UV and LCMSMS. HPLC intra-day accuracy ranged from 100.51 to 103.19%. LCMSMS accuracy ranged from 89.72 to 106.29%. The correlation coefficient between both methods was r(2)=0.96. HPLC can be used for imatinib levels' determinations in patients accurately and precisely. Copyright 2009 Elsevier Ltd. All rights reserved.

  4. High Performance Liquid Chromatography Method for the ...

    African Journals Online (AJOL)

    chromatography (HPLC) technique with UV-VIS detection method was developed for the determination of the compound in rat ... Keywords: Anethole, High performance liguid chromatography, Star anise, Essential oil, Rat plasma,. Illicium verum Hook. .... solution of anethole. Plasma proteins were precipitated by adding 0.3.

  5. Porphyrins profile by high performance liquid chromatography ...

    African Journals Online (AJOL)

    Most porphyria symptoms are nonspecific and occur intermittently; resulting frequently in missed diagnosis since the disease itself is a rare one. The aim of the study is to establish a new reliable and accurate laboratory method for separation, identification and quantitation of urinary porphyrins by liquid chromatography ...

  6. Molecularly imprinted polymer for the extraction of parabens from environmental solid samples prior to their determination by high performance liquid chromatography-ultraviolet detection.

    Science.gov (United States)

    Núñez, L; Turiel, E; Martin-Esteban, A; Tadeo, J L

    2010-03-15

    An analytical methodology incorporating a molecularly imprinted solid-phase extraction procedure (MISPE) has been developed for the determination of parabens in environmental solid samples. Four different polymers were prepared combining the use of acetonitrile or toluene as porogen, and 4-vinylpyridine (VP) or methacrylic acid (MAA) as monomer, using benzylparaben (BzP) as a template molecule. Although all the polymers were able to recognize the template in rebinding experiments, the MIP prepared in toluene using MAA showed better performance. This polymer was also capable of recognizing other parabens (methyl, ethyl, isopropyl, propyl, isobutyl, butyl and benzylparaben) allowing to develop an appropriated MISPE procedure for this family of compounds. The extraction of the parabens from environmental solid samples was performed by ultrasonic assisted extraction in small columns (SAESC), and this procedure next to MISPE as clean-up step followed by HPLC-UV determination was successfully used for the determination of parabens in soil and sediment samples of different locations. Recoveries ranging from 80% to 90% have been achieved depending on the compound and the samples, and limits of detection (LODs) were under 1 ng g(-1) for all the compounds, making this method suitable for the determination of parabens in environmental solid matrices. The method was further applied to the determination of paraben contents in real samples, founding levels up to 11.5 ng g(-1) in sea sediments. Copyright (c) 2009 Elsevier B.V. All rights reserved.

  7. ANALYSIS OF AMINO ACIDS BY HIGH PERFORMANCE LIQUID CHROMATOGRAPHY

    Directory of Open Access Journals (Sweden)

    Qurat E Noor Baig

    2016-06-01

    Full Text Available Amino acids are the building blocks of proteins and are considered as the key precursors for the formation of hormones and low molecular weight nitrogenous substances with biological importance. Since the analysis of amino acids has been carried out for both qualitative and quantitative purposes with an aim to study their levels in the plasma concentration, the quantitative determination, in particular, also helps in the diagnosis of different diseases associated with their deficiency. This review article deals with the determination of amino acids by chromatographic methods which include ion-exchange chromatography (IEC, high performance liquid chromatography (HPLC, reverse phase-high performance liquid chromatography (RP-HPLC and ultra-performance liquid chromatography (UPLC. The review will also give an idea for the preparation of samples, derivatization methods for the analysis of amino acids (direct and indirect methods and separation of amino acids by high performance liquid chromatographic technique.

  8. Sensitive high performance liquid chromatographic method for the ...

    African Journals Online (AJOL)

    A new simple, sensitive, cost-effective and reproducible high performance liquid chromatographic (HPLC) method for the determination of proguanil (PG) and its metabolites, cycloguanil (CG) and 4-chlorophenylbiguanide (4-CPB) in urine and plasma is described. The extraction procedure is a simple three-step process ...

  9. 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.

  10. Quantification of Tea Flavonoids by High Performance Liquid Chromatography

    Science.gov (United States)

    Freeman, Jessica D.; Niemeyer, Emily D.

    2008-01-01

    We have developed a laboratory experiment that uses high performance liquid chromatography (HPLC) to quantify flavonoid levels in a variety of commercial teas. Specifically, this experiment analyzes a group of flavonoids known as catechins, plant-derived polyphenolic compounds commonly found in many foods and beverages, including green and black…

  11. An optimized gossypol high-performance liquid chromatography ...

    Indian Academy of Sciences (India)

    A comparative study on gossypol content of various genetic types of pigment glands of cotton varieties was conducted through an optimized high-performance liquid chromatography (HPLC) on a C18 column (4.6 mm × 250 mm, 5 m particle) with methanol–0.5% acetic acid aqueous solution, 90 : 10 (v/v), as mobile phase, ...

  12. Buffer-Free High Performance Liquid Chromatography Method for ...

    African Journals Online (AJOL)

    Purpose: To develop and validate a simple, economical and reproducible high performance liquid chromatographic (HPLC) method for the determination of theophylline in pharmaceutical dosage forms. Method: Caffeine was used as the internal standard and reversed phase C-18 column was used to elute the drug and ...

  13. Spectrum-effect relationships between high performance liquid ...

    African Journals Online (AJOL)

    Purpose: To investigate the spectrum-effect relationships between high performance liquid chromatography (HPLC) fingerprints and duodenum contractility of charred areca nut (CAN) on rats. Methods: An HPLC method was used to establish the fingerprint of charred areca nut (CAN). The promoting effect on contractility of ...

  14. Rapid extraction and determination of amphetamines in human urine samples using dispersive liquid-liquid microextraction and solidification of floating organic drop followed by high performance liquid chromatography.

    Science.gov (United States)

    Ahmadi-Jouibari, Toraj; Fattahi, Nazir; Shamsipur, Mojtaba

    2014-06-01

    A novel, rapid, simple and sensitive dispersive liquid-liquid microextraction method based on the solidification of floating organic drop (DLLME-SFO) combined with high-performance liquid chromatography-ultraviolet detection (HPLC-UV) was used to determine amphetamine and methamphetamine in urine samples. The factors affecting the extraction efficiency of DLLME-SFO such as the kind and volume of the extraction and the disperser solvents, effect of concentration of K2CO3 and extraction time were investigated and the optimal extraction conditions were established. Under the optimum conditions (extraction solvent: 30.0μl 1-undecanol; disperser solvent: 300μl acetonitrile; buffer concentration: 2% (w/v) K2CO3 and extraction time: 1min), calibration curves are linear in the range of 10-3000μgl(-1) and limit of detections (LODs) are in the range of 2-8μgl(-1). The relative standard deviations (RSDs) for 100μgl(-1) of amphetamine and methamphetamine in diluted urine are in the range of 6.2-7.8% (n=7). The method was successfully applied for the determination of amphetamine and methamphetamine in the actual urine samples. The relative recoveries of urine samples spiked with amphetamine and methamphetamine are 87.8-113.2%. The obtained results show that DLLME-SFO combined with HPLC-UV is a fast and simple method for the determination of amphetamine and methamphetamine in urine. Copyright © 2014 Elsevier B.V. All rights reserved.

  15. Analysis of Tocopherols by High Performance Liquid Chromatography

    Directory of Open Access Journals (Sweden)

    B. Edison

    2009-01-01

    Full Text Available : Gas chromatography is the key technique for organic components and also for tocopherols analysis. High performance liquid chromatography has an important role to take part in applications such as the handling of less usual samples, prevention of degradation of heat sensitive functional groups and for micro preparative purposes. Many approaches for development of improved methods are suggested, especially for reversed phase applications.

  16. Trends in High Performance Liquid Chromatography for Cultural Heritage.

    Science.gov (United States)

    Degano, Ilaria; La Nasa, Jacopo

    2016-04-01

    The separation, detection and quantitation of specific species contained in a sample in the field of Cultural Heritage requires selective, sensitive and reliable methods. Procedures based on liquid chromatography fulfil these requirements and offer a wide range of applicability in terms of analyte types and concentration range. The main applications of High Performance Liquid Chromatography in this field are related to the separation and detection of dyestuffs in archaeological materials and paint samples by reversed-phase liquid chromatography with suitable detectors. The relevant literature will be revised, with particular attention to sample treatment strategies and future developments. Reversed phase chromatography has also recently gained increasing importance in the analysis of lipid binders and lipid materials in archaeological residues: the main advantages and disadvantages of the new approaches will be discussed. Finally, the main applications of ion chromatography and size exclusion chromatography in the field of Cultural Heritage will be revised in this chapter.

  17. [Determination of amygdalin in hawthorn by high performance liquid chromatography].

    Science.gov (United States)

    Lü, Weifeng; Ding, Mingyu

    2005-09-01

    A suitable method for extraction of amygdalin from hawthorn has been established. At first, the lipophilic components were removed with petroleum ether by ultrasonic extraction. The amygdalin was then extracted by methanol in a Soxhlet's apparatus. For quantitation, a high performance liquid chromatographic method was developed by using a reversed-phase C18 column, mobile phase of methanol-water (15:85, v/v) and a detection wavelengh of 215 nm. It can be concluded that the content of amygdalin is higher in the seeds than that in the hawthorn powder without the seeds and the yield of amygdalin is higher in the hawthorn pieces than that in the hawthorn powder.

  18. Alcoholic fermentation process control by high-performance liquid chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Morawski, J.; Dincer, A.K.; Ivie, K.

    1983-02-01

    In large-scale fermentation for energy production high-performance liquid chromatography (HPLC) provides an accurate method of monitoring the original oligosaccharides and polysaccharides, as well as their hydrolysis to fermentable monosaccharides. Also measuring the saccharide and alcohol content of the fermentation vat allows overseeing of the process, providing the capability of allowing the fermentation to proceed to the most economical level prior to distillation. Another application for HPLC in a large-scale fermentation for energy is to analyze the stillage for its ethanol content during distillation, in order to observe the efficiency of the still. HPLC can separate and detect very low levels, (i.e., 100 parts per million), of ethanol to yield information concerning the distillation process. These capabilities indicate that HPLC is an extremely useful efficient instrument to the fermentation industries. (Refs. 2).

  19. Separation of human tear proteins by high performance liquid chromatography.

    Science.gov (United States)

    Boonstra, A; Kijlstra, A

    1984-12-01

    The optimal conditions for separating human tear proteins by high performance liquid chromatography (HPLC) using a Waters I-125 gel filtration column were investigated. Several elution buffers were tested including phosphate buffer alone and phosphate buffer to which varying amounts of NaCl or 0.1% Tween was added. The combination of phosphate buffer (pH 5.28), 0.5 M NaCl and 0.1% Tween gave the best resolution and a recovery of 90% of the proteins applied. Tear lactoferrin was shown to adhere to the column packing when the molarity of the elution buffer was not high enough. Using optimal conditions, the tear proteins IgA, lactoferrin and lysozyme were identified in distinct peaks after a preparative HPLC run. When used in combination with Schirmer strips as a tear sampling method, HPLC was shown to be a rapid, simple and reproducible way of investigating the composition of tear proteins.

  20. A quantitative method for the determination of bosutinib in human plasma using high-performance liquid chromatography and ultraviolet detection.

    Science.gov (United States)

    Sumimoto, Takahiro; Nakahara, Ryosuke; Sato, Yuhki; Itoh, Hiroki

    2018-01-01

    We propose a simple, sensitive, and fast high-performance liquid chromatography ultraviolet detection (HPLC-UV) method for the quantitative determination of bosutinib in human plasma. Plasma samples were processed using an Oasis hydrophilic-lipophilic balance extraction cartridge (1 mL, 30 mg). Bosutinib and the internal standard imatinib were separated using a mobile phase of 0.5% Na2 PO4 H2 O (pH 3.5)-acetonitrile-methanol (55:25:20, v/v/v) on a CAPCELL PAK C18 MG II reversed-phase column 250 nm×4.6 nm i.d., at a flow rate of 1.0 mL/min, with ultraviolet detection at 250 nm. The calibration curve exhibited linearity over the bosutinib concentration range of 25-1500 ng/mL at 250 nm, with coefficient of variation for intraday precision of 2.42%, 6.04%, and 1.11% for 100, 250, and 1500 ng/mL, respectively, of bosutinib. The lower limit of detection was 20 ng/mL. The extraction recovery rates for bosutinib ranged from 84.36% to 85.82%. The intra- and interday precision was below 8.7%, and the accuracy ranged from -5.95% to 5.85% over the linear range. No notable matrix effects or astaticism were observed. The proposed HPLC-UV method was successfully applied as an assay to detect bosutinib in human plasma. © 2017 Wiley Periodicals, Inc.

  1. Determination of saffron quality by high-performance liquid chromatography.

    Science.gov (United States)

    Valle García-Rodríguez, M; Serrano-Díaz, Jéssica; Tarantilis, Petros A; López-Córcoles, Horacio; Carmona, Manuel; Alonso, Gonzalo L

    2014-08-13

    The aim of this work was to propose a high-performance liquid chromatography with diode array detection (HPLC-DAD) method for determining the three main compounds responsible for determining the quality of saffron (crocetin esters, picrocrocin, and safranal) by preparing an aqueous extract according to the ISO 3632 standard to solve the difficulty that this standard has for aroma and taste determination by ultraviolet-visible spectroscopy. Toward this aim, laboratory-isolated picrocrocin, a safranal standard with a purity of ≥ 88%, trans-crocetin di(β-D-gentiobiosyl) ester (trans-4-GG) and trans-crocetin (β-D-glucosyl)-(β-D-gentiobiosyl) ester (trans-3-Gg) standards, both with a purity of ≥ 99%, and 50 different saffron spice samples from Italy, Iran, Greece, and Spain were used in the intralaboratory validation of the HPLC method. The analytical method proposed was adequate in terms of linearity, selectivity, sensitivity, and accuracy for determining the three foremost parameters that define the quality of saffron using only a saffron solution prepared according to the ISO 3632 standard.

  2. Determination of Finasteride in Tablets by High Performance Liquid Chromatography

    Directory of Open Access Journals (Sweden)

    K. Basavaiah

    2007-01-01

    Full Text Available A rapid, highly sensitive high performance liquid chromatographic method has been developed for the determination of finasteride(FNS in bulk drug and in tablets. FNS was eluted from a ODS C18 reversed phase column at laboratory temperature (30 ± 2°C with a mobile phase consisting of methanol and water (80+20 at a flow rate of 1 mL min-1 with UV detection at 225 nm. The retention time was ∼ 6.1 min and each analysis took not more than 10 min. Quantitation was achieved by measurement of peak area without using any internal standard. Calibration graph was linear from 2.0 to 30 μg mL-1 with limits of detection (LOD and quantification (LOQ being 0.2 and 0.6 μg mL-1, respectively. The method was validated according to the current ICH guidelines. Within-day co efficients of variation (CV ranged from 0.31 to 0.69% and between-day CV were in the range 1.2-3.2%. Recovery of FNS from the pharmaceutical dosage forms ranged from 97.89 – 102.9 with CV of 1.41-4.13%. The developed method was compared with the official method for FNS determination in its tablet forms.

  3. Agarose-chitosan-C18film micro-solid phase extraction combined with high performance liquid chromatography for the determination of phenanthrene and pyrene in chrysanthemum tea samples.

    Science.gov (United States)

    Ng, Nyuk Ting; Sanagi, Mohd Marsin; Wan Ibrahim, Wan Nazihah; Wan Ibrahim, Wan Aini

    2017-05-01

    Agarose-chitosan-immobilized octadecylsilyl-silica (C 18 ) film micro-solid phase extraction (μSPE) was developed and applied for the determination of phenanthrene (PHE) and pyrene (PYR) in chrysanthemum tea samples using high performance liquid chromatography-ultraviolet detection (HPLC-UV). The film of blended agarose and chitosan allows good dispersion of C 18 , prevents the leaching of C 18 during application and enhances the film mechanical stability. Important μSPE parameters were optimized including amount of sorbent loading, extraction time, desorption solvent and desorption time. The matrix match calibration curves showed good linearity (r⩾0.994) over a concentration range of 1-500ppb. Under the optimized conditions, the proposed method showed good limits of detection (0.549-0.673ppb), good analyte recoveries (100.8-105.99%) and good reproducibilities (RSDs⩽13.53%, n=3) with preconcentration factors of 4 and 72 for PHE and PYR, respectively. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. Sensitive and Selective Reversed-Phase High Performance Liquid ...

    African Journals Online (AJOL)

    Methods: Pre-column sample clean-up was carried out by liquid-liquid extraction of the analytes with chloroform: isopropanol (70:30) solution after alkalization of 1000 μL sample and spiking of internal standard, morphine. The samples were chromatographed in a reversed-phase (C-18) ultra sphere silica (5μm particle size ...

  5. High performance batteries with carbon nanomaterials and ionic liquids

    Science.gov (United States)

    Lu, Wen [Littleton, CO

    2012-08-07

    The present invention is directed to lithium-ion batteries in general and more particularly to lithium-ion batteries based on aligned graphene ribbon anodes, V.sub.2O.sub.5 graphene ribbon composite cathodes, and ionic liquid electrolytes. The lithium-ion batteries have excellent performance metrics of cell voltages, energy densities, and power densities.

  6. High performance ultracapacitors with carbon nanomaterials and ionic liquids

    Science.gov (United States)

    Lu, Wen; Henry, Kent Douglas

    2012-10-09

    The present invention is directed to the use of carbon nanotubes and/or electrolyte structures in various electrochemical devices, such as ultracapacitors having an ionic liquid electrolyte. The carbon nanotubes are preferably aligned carbon nanotubes. Compared to randomly entangled carbon nanotubes, aligned carbon nanotubes can have better defined pore structures and higher specific surface areas.

  7. High Performance Mars Liquid Cooling and Ventilation Garment Project

    Science.gov (United States)

    Terrier, Douglas; Clayton, Ronald; Whitlock, David; Conger, Bruce

    2015-01-01

    EVA space suit mobility in micro-gravity is enough of a challenge and in the gravity of Mars, improvements in mobility will enable the suited crew member to efficiently complete EVA objectives. The idea proposed is to improve thermal efficiencies of the liquid cooling and ventilation garment (LCVG) in the torso area in order to free up the arms and legs by removing the liquid tubes currently used in the ISS EVA suit in the limbs. By using shaped water tubes that greatly increase the contact area with the skin in the torso region of the body, the heat transfer efficiency can be increased to provide the entire liquid cooling requirement and increase mobility by freeing up the arms and legs. Additional potential benefits of this approach include reduced LCVG mass, enhanced evaporation cooling, increased comfort during Mars EVA tasks, and easing of the overly dry condition in the helmet associated with the Advanced Extravehicular Mobility Unit (EMU) ventilation loop currently under development.

  8. A combination of solid-phase extraction and dispersive solid-phase extraction effectively reduces the matrix interference in liquid chromatography-ultraviolet detection during pyraclostrobin analysis in perilla leaves.

    Science.gov (United States)

    Farha, Waziha; Rahman, Md Musfiqur; Abd El-Aty, A M; Jung, Da-I; Kabir, Md Humayun; Choi, Jeong-Heui; Kim, Sung-Woo; Im, So Jeong; Lee, Young-Jun; Shin, Ho-Chul; Kwon, Chan-Hyeok; Son, Young-Wook; Lee, Kang-Bong; Shim, Jae-Han

    2015-12-01

    Perilla leaves contain many interfering substances; thus, it is difficult to protect the analytes during identification and integration. Furthermore, increasing the amount of sample to lower the detection limit worsens the situation. To overcome this problem, we established a new method using a combination of solid-phase extraction and dispersive solid-phase extraction to analyze pyraclostrobin in perilla leaves by liquid chromatography with ultraviolet absorbance detection. The target compound was quantitated by external calibration with a good determination coefficient (R(2) = 0.997). The method was validated (in triplicate) with three fortification levels, and 79.06- 89.10% of the target compound was recovered with a relative standard deviation <4. The limits of detection and quantification were 0.0033 and 0.01 mg/kg, respectively. The method was successfully applied to field samples collected from two different areas at Gwangju and Muan. The decline in the resiudue concentrations was best ascribed to a first-order kinetic model with half-lives of 5.7 and 4.6 days. The variation between the patterns was attributed to humidity. Copyright © 2015 John Wiley & Sons, Ltd.

  9. High-performance liquid chromatography - Ultraviolet method for the determination of total specific migration of nine ultraviolet absorbers in food simulants based on 1,1,3,3-Tetramethylguanidine and organic phase anion exchange solid phase extraction to remove glyceride.

    Science.gov (United States)

    Wang, Jianling; Xiao, Xiaofeng; Chen, Tong; Liu, Tingfei; Tao, Huaming; He, Jun

    2016-06-17

    The glyceride in oil food simulant usually causes serious interferences to target analytes and leads to failure of the normal function of the RP-HPLC column. In this work, a convenient HPLC-UV method for the determination of the total specific migration of nine ultraviolet (UV) absorbers in food simulants was developed based on 1,1,3,3-tetramethylguanidine (TMG) and organic phase anion exchange (OPAE) SPE to efficiently remove glyceride in olive oil simulant. In contrast to the normal ion exchange carried out in an aqueous solution or aqueous phase environment, the OPAE SPE was performed in the organic phase environments, and the time-consuming and challenging extraction of the nine UV absorbers from vegetable oil with aqueous solution could be readily omitted. The method was proved to have good linearity (r≥0.99992), precision (intra-day RSD≤3.3%), and accuracy(91.0%≤recoveries≤107%); furthermore, the lower limit of quantifications (0.05-0.2mg/kg) in five types of food simulants(10% ethanol, 3% acetic acid, 20% ethanol, 50% ethanol and olive oil) was observed. The method was found to be well suited for quantitative determination of the total specific migration of the nine UV absorbers both in aqueous and vegetable oil simulant according to Commission Regulation (EU) No. 10/2011. Migration levels of the nine UV absorbers were determined in 31 plastic samples, and UV-24, UV-531, HHBP and UV-326 were frequently detected, especially in olive oil simulant for UV-326 in PE samples. In addition, the OPAE SPE procedure was also been applied to efficiently enrich or purify seven antioxidants in olive oil simulant. Results indicate that this procedure will have more extensive applications in the enriching or purification of the extremely weak acidic compounds with phenol hydroxyl group that are relatively stable in TMG n-hexane solution and that can be barely extracted from vegetable oil. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. Determination of sulfonamides in butter samples by ionic liquid magnetic bar liquid-phase microextraction high-performance liquid chromatography.

    Science.gov (United States)

    Wu, Lijie; Song, Ying; Hu, Mingzhu; Xu, Xu; Zhang, Hanqi; Yu, Aimin; Ma, Qiang; Wang, Ziming

    2015-01-01

    A novel, simple, and environmentally friendly pretreatment method, ionic liquid magnetic bar liquid-phase microextraction, was developed for the determination of sulfonamides in butter samples by high-performance liquid chromatography. The ionic liquid magnetic bar was prepared by inserting a stainless steel wire into the hollow of a hollow fiber and immobilizing ionic liquid in the micropores of the hollow fiber. In the extraction process, the ionic liquid magnetic bars were used to stir the mixture of sample and extraction solvent and enrich the sulfonamides in the mixture. After extraction, the analyte-adsorbed ionic liquid magnetic bars were readily isolated with a magnet from the extraction system. It is notable that the present method was environmentally friendly since water and only several microliters of ionic liquid were used in the whole extraction process. Several parameters affecting the extraction efficiency were investigated and optimized, including the type of ionic liquid, sample-to-extraction solvent ratio, the number of ionic liquid magnetic bars, extraction temperature, extraction time, salt concentration, stirring speed, pH of the extraction solvent, and desorption conditions. The recoveries were in the range of 73.25-103.85 % and the relative standard deviations were lower than 6.84 %. The experiment results indicated that the present method was effective for the extraction of sulfonamides in high-fat content samples.

  11. HIGH PERFORMANCE LIQUID CHROMATOGRAPHIC SEPARATION OF THE ENANTIOMERS OF 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) was obtained on polysaccharide enantioselective HPLC columns using alkane-alcohol mobile phase. The OP pesticides were crotoxyphos, dialifor, fonofos, fenamiph...

  12. Covalent triazine framework-1 as adsorbent for inline solid phase extraction-high performance liquid chromatographic analysis of trace nitroimidazoles in porcine liver and environmental waters.

    Science.gov (United States)

    Zhong, Cheng; Chen, Beibei; He, Man; Hu, Bin

    2017-02-03

    In this study, covalent triazine framework-1 (CTF-1) was adopted as solid phase extraction (SPE) sorbents, and a method of SPE inline coupled with high performance liquid chromatography-ultraviolet (HPLC-UV) detection was developed for trace analysis of three nitroimidazolaes (including metronidazole, ronidazole and dimetridazole) in porcine liver and environmental water samples. CTF-1 has rich π-electron and N containing triazine, thus can form π-π interaction and intermolecular hydrogen bond with three target polar nitroimidazoles, resulting in high extraction efficiency (87%-98%). Besides, CTF-1 has large specific area, which benefits rapid mass transfer and low column pressure, leading to fast adsorption/desorption dynamics. Several parameters affecting inline SPE including pH, sample flow rate, sample volume, desorption reagents, elution flow rate, elution volume, and ionic strength were investigated. Under the optimal experimental conditions, the limits of detection (S/N=3) were found to be in the range of 0.11-0.13μg/L. The enrichment factors (EFs) ranged from 52 to 59 fold (theoretical EF was 60-fold). The relative standard deviations were in the range of 4.3-9.4% (n=7, c=1μg/L), and the linear range was 0.5-500μg/L for three target analytes. The sample throughput is 7/h. The proposed method was successfully applied to the analysis of nitroimidazoles in porcine liver and environmental water samples with good recoveries for the spiked samples. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Arsenic speciation in edible alga samples by microwave-assisted extraction and high performance liquid chromatography coupled to atomic fluorescence spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Salgado, S. [Departamento de Ingenieria Civil: Tecnologia Hidraulica y Energetica, Escuela Universitaria de Ingenieria Tecnica de Obras Publicas, Universidad Politecnica de Madrid, Alfonso XII 3 y 5, 28014 Madrid (Spain); Quijano, M.A., E-mail: marian.quijano@upm.es [Departamento de Ingenieria Civil: Tecnologia Hidraulica y Energetica, Escuela Universitaria de Ingenieria Tecnica de Obras Publicas, Universidad Politecnica de Madrid, Alfonso XII 3 y 5, 28014 Madrid (Spain); Bonilla, M.M. [Departamento de Ingenieria Civil: Tecnologia Hidraulica y Energetica, Escuela Universitaria de Ingenieria Tecnica de Obras Publicas, Universidad Politecnica de Madrid, Alfonso XII 3 y 5, 28014 Madrid (Spain)

    2012-02-10

    Highlights: Black-Right-Pointing-Pointer Total As and As species were analyzed in edible marine algae. Black-Right-Pointing-Pointer A microwave-assisted extraction method with deionized water was applied. Black-Right-Pointing-Pointer As compounds identified comprised DMA, As(V) and four arsenosugars Black-Right-Pointing-Pointer Considerably high As(V) concentrations were found in the most of the algae studied. - Abstract: Twelve commercially available edible marine algae from France, Japan and Spain and the certified reference material (CRM) NIES No. 9 Sargassum fulvellum were analyzed for total arsenic and arsenic species. Total arsenic concentrations were determined by inductively coupled plasma atomic emission spectrometry (ICP-AES) after microwave digestion and ranged from 23 to 126 {mu}g g{sup -1}. Arsenic species in alga samples were extracted with deionized water by microwave-assisted extraction and showed extraction efficiencies from 49 to 98%, in terms of total arsenic. The presence of eleven arsenic species was studied by high performance liquid chromatography-ultraviolet photo-oxidation-hydride generation atomic-fluorescence spectrometry (HPLC-(UV)-HG-AFS) developed methods, using both anion and cation exchange chromatography. Glycerol and phosphate sugars were found in all alga samples analyzed, at concentrations between 0.11 and 22 {mu}g g{sup -1}, whereas sulfonate and sulfate sugars were only detected in three of them (0.6-7.2 {mu}g g{sup -1}). Regarding arsenic toxic species, low concentration levels of dimethylarsinic acid (DMA) (<0.9 {mu}g g{sup -1}) and generally high arsenate (As(V)) concentrations (up to 77 {mu}g g{sup -1}) were found in most of the algae studied. The results obtained are of interest to highlight the need to perform speciation analysis and to introduce appropriate legislation to limit toxic arsenic species content in these food products.

  14. Development of a High-Performance Liquid Chromatographic Method for Asiaticoside Quantification in Different Skin Layers after Topical Application of a Centella asiatica Extract.

    Science.gov (United States)

    da Rocha, Priscila Bianca Rodrigues; Souza, Bruno Dos Santos; Andrade, Lígia Marquez; Marreto, Ricardo Neves; Lima, Eliana Martins; Taveira, Stephânia Fleury

    2017-12-01

    The topical application of Centella asiatica extract has been commonly used for many different purposes but especially for cosmetic use in the treatment of gynoid lipodystrophy. Asiaticoside, the most active component in this extract, is responsible for its therapeutic activities. However, little is known to date about asiaticoside skin penetration. Thus, an analytical method for asiaticoside quantification in different skin layers after the topical application of C. asiatica extract was developed and skin permeation studies were performed with the plant extract to apply the analytical method developed. An extraction procedure to recover asiaticoside from the biological matrix was also developed. Asiaticoside was assayed by HPLC/UV (high-performance liquid chromatography-ultraviolet detection) using a gradient of ACN (acetonitrile) and 0.2% phosphoric acid (flow rate of 1.0 mL/min). The analytical procedure was validated according to U. S. Food and Drug Administration guidelines. Selectivity was shown, as endogenous skin components did not interfere with the asiaticoside peak. Analytical curve was linear (3 to 60 µg/mL) and the lower limit of quantification was determined (3 µg/mL). Asiaticoside recoveries from skin samples were 95.1% and 66.7% for the stratum corneum and remaining skin, respectively. After 48 h of in vitro permeation studies, a substantial amount of asiaticoside was quantified in the skin layers. The presence of asiaticoside was also detected in the receptor solution of Franz diffusion cells after 48 h (5.81 ± 1.00 µg/mL). The method was reliable and reproducible for asiaticoside quantification in skin samples, thereby making it possible to determine the cutaneous penetration profile of this drug in permeation studies. Georg Thieme Verlag KG Stuttgart · New York.

  15. Simultaneous quantification of triterpenoic acids by high performance liquid chromatography method in the extracts of gum resin of Boswellia serrata obtained by different extraction techniques.

    Science.gov (United States)

    Sharma, Neha; Bhardwaj, Vikram; Singh, Samar; Ali, Sheikh Abid; Gupta, D K; Paul, Satya; Satti, Naresh K; Chandra, Suresh; Verma, Mahendra K

    2016-01-01

    Boswellia serrata, also known as Indian frankincense is a commercially important medicinal plant which has been used for hundreds of years as an Ayurvedic medicine for the attempted treatment of arthritis. It contains naturally occurring triterpenoic acids, called as boswellic acids (BA's). A highly reproducible High performance liquid chromatography-ultraviolet diode array detection (HPLC-UV-DAD) method was developed for the simultaneous determination and quantitative analysis of eight major triterpenoic acids in Boswellia serrata gum resin obtained by different extraction techniques. All the calibration curves exhibited good linear regression (R(2) > 0.997) within the test ranges. The established method showed good precision and overall recoveries of the boswellic acids. The eight triterpenoic acids coded as BS-1 (11-keto-beta-boswellic acid), BS-2 (3-O-acetyl-11-keto-beta-boswellic acid), BS-3 (3-keto tirucallic acid), BS-4 (3-O-acetyl-alpha-tirucallic acid), BS-5 (3-O-acetyl-beta-tirucallic acid), BS-6 (alpha-boswellic acid), BS-7 (beta-boswellic acid) and BS-8 (3-O-acetyl-beta-boswellic acid) were isolated from the processed gum resin of Boswellia serrata by column chromatography. The proposed HPLC method is simple, reliable and has been very useful for the qualitative as well as quantitative analysis of boswellic acids in the gum resin of Boswellia serrata. The proposed method allows to quantify boswellic acids in appreciable amounts by HPLC-UV (DAD) method in the extracts and the available marketed formulations.Graphical abstractIsolation & separation of eight Triterpenoic acids from Boswellia serrata.

  16. High performance liquid-level sensor based on mPOFBG for aircraft applications

    DEFF Research Database (Denmark)

    Marques, C. A. F.; Pospori, A.; Saez-Rodriguez, D.

    2015-01-01

    A high performance liquid-level sensor based on microstructured polymer optical fiber Bragg grating (mPOFBG) array sensors is reported in detail. The sensor sensitivity is found to be 98pm/cm of liquid, enhanced by more than a factor of 9 compared to a reported silica fiber-based sensor....

  17. Salting-out assisted liquid-liquid extraction coupled to dispersive liquid-liquid microextraction for the determination of chlorophenols in wine by high-performance liquid chromatography.

    Science.gov (United States)

    Fan, Yingying; Hu, Shibin; Liu, Shuhui

    2014-12-01

    A novel procedure of sample preparation combined with high-performance liquid chromatography with diode array detection is introduced for the analysis of highly chlorinated phenols (trichlorophenols, tetrachlorophenols, and pentachlorophenol) in wine. The main features of the proposed method are (i) low-toxicity diethyl carbonate as extraction solvent to selectively extract the analytes without matrix effect, (ii) the combination of salting-out assisted liquid-liquid extraction and dispersive liquid-liquid microextraction to achieve an enrichment factor of 334-361, and (iii) the extract is analyzed by high-performance liquid chromatography to avoid derivatization. Under the optimum conditions, correlation coefficients (r) were >0.997 for calibration curves in the range 1-80 ng/mL, detection limits and quantification limits ranged from 0.19 to 0.67 and 0.63 to 2.23 ng/mL, respectively, and relative standard deviation was <8%. The method was applied for the determination of chlorophenols in real wines, with recovery rates in the range 82-104%. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. New methods and materials for solid phase extraction and high performance liquid chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Dumont, Philip John [Iowa State Univ., Ames, IA (United States)

    1996-04-23

    This paper describes methods for solid phase extraction and high performance liquid chromatography (HPLC). The following are described: Effects of Resin Sulfonation on the Retention of Polar Organic Compounds in Solid Phase Extraction; Ion-Chromatographic Separation of Alkali Metals In Non-Aqueous Solvents; Cation-Exchange Chromatography in Non-Aqueous Solvents; and Silicalite As a Stationary Phase For HPLC.

  19. Coupling nanoliter high-performance liquid chromatography to inductively coupled plasma mass spectrometry for arsenic speciation.

    Science.gov (United States)

    Cheng, Heyong; Shen, Lihuan; Liu, Jinhua; Xu, Zigang; Wang, Yuanchao

    2017-12-23

    Nanoliter high-performance liquid chromatography shows low consumption of solvents and samples, offering one of the best choices for arsenic speciation in precious samples in combination with inuctively coupled plasma mass spectrometry. A systematic investigation on coupling nanoliter high-performance liquid chromatography to inductively coupled plasma mass spectrometry from instrument design to injected sample volume and mobile phase was performed in this study. Nanoflow mobile phase was delivered by flow splitting using a conventional high-pressure pump with reuse of mobile phase waste. Dead volume was minimized to 60 nL for the sheathless interface based on the previously developed nanonebulizer. Capillary columns for nanoliter high-performance liquid chromatography were found to be sensitive to sample loading volume. An apparent difference was also found between the mobile phases for nanoliter and conventional high-performance liquid chromatography. Baseline separation of arsenite, arsenate, monomethylarsenic, and dimethylarsenic was achieved within 11 min on a 15 cm C18 capillary column and within 12 min on a 25 cm strong anion exchange column. Detection limits of 0.9-1.8 μg/L were obtained with precisions variable in the range of 1.6-4.2%. A good agreement between determined and certified values of a certified reference material of human urine (GBW 09115) validated its accuracy along with good recoveries (87-102%). © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. An Advanced, Interactive, High-Performance Liquid Chromatography Simulator and Instructor Resources

    Science.gov (United States)

    Boswell, Paul G.; Stoll, Dwight R.; Carr, Peter W.; Nagel, Megan L.; Vitha, Mark F.; Mabbott, Gary A.

    2013-01-01

    High-performance liquid chromatography (HPLC) simulation software has long been recognized as an effective educational tool, yet many of the existing HPLC simulators are either too expensive, outdated, or lack many important features necessary to make them widely useful for educational purposes. Here, a free, open-source HPLC simulator is…

  1. High-Performance Liquid Chromatography in the Undergraduate Chemical Engineering Laboratory

    Science.gov (United States)

    Frey, Douglas D.; Guo, Hui; Karnik, Nikhila

    2013-01-01

    This article describes the assembly of a simple, low-cost, high-performance liquid chromatography (HPLC) system and its use in the undergraduate chemical engineering laboratory course to perform simple experiments. By interpreting the results from these experiments students are able to gain significant experience in the general method of…

  2. Determination for Synthesis and Content of Tetrahydropalmatine Based on High Performance Liquid Chromatography

    OpenAIRE

    Yuanming Zhang

    2014-01-01

    Tetrahydropalmatine is a kind of food additive with useful medicine value (dietary supplement), the tetrahydropalmatine synthetic process by using high performance liquid chromatography method was researched in the study, the experiments show that the dissolution rate of active ingredients in the tetrahydropalmatine water extract synthesized by this method has increased and the amount of active ingredient has greatly improved.

  3. Comparison of high performance liquid chromatography and enzymatic analysis of soluble carbohydrates in loblolly pine

    Science.gov (United States)

    Patricia L. Faulkner; Michele M. Schoeneberger; Kim H. Ludovici

    1993-01-01

    Foliar tissue was collected from a field study designed to test impacts of atmospheric pollutants on loblolIy pine (Pinus taeda L.) seedlings. Standard enzymatic (ENZ) and high performance liquid chromatography (HPLC) methods were used to analyze the tissue for soluble sugars. A comparison of the methods revealed no significant diffennces in accuracy...

  4. High Performance Liquid Chromatographic Analysis of Phytoplankton Pigments Using a C16-Amide Column

    Science.gov (United States)

    A reverse-phase high performance liquid chromatographic (RP-HPLC) method was developed to analyze in a single run, most polar and non-polar chlorophylls and carotenoids from marine phytoplankton. The method is based on a RP-C16-Amide column and a ternary gradient system consistin...

  5. DETERMINATION OF CHLOROPHENOLS, NITROPHENOLS, AND METHYLPHENOLS IN GROUND-WATER SAMPLES USING HIGH PERFORMANCE LIQUID CHROMATOGRAPHY

    Science.gov (United States)

    A high performance liquid chromatography (HPLC) method was developed to quantitatively determine phenolic compounds and their isomers in aqueous samples. The HPLC method can analyze a mixture of 15 contaminants in the same analytical run with an analysis time of 25 minutes. The...

  6. DETERMINATION OF CHLOROPHEONIS, NITROPHENOIS AND METHYLPHENOIS IN GROUND-WATER SAMPLES USING HIGH PERFORMANCE LIQUID CHROMATOGRAPHY

    Science.gov (United States)

    A high performance liquid chromatography (HPLC) method was developed to quantitatively determine phenolic compounds and their isomers in aqueous samples. The HPLC method can analyze a mixture of 15 contaminants in the same analytical run with an analysis time of 25 minutes. The...

  7. 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…

  8. High-performance liquid chromatography determination of dapsone, monoacetyldapsone, and pyrimethamine in filter paper blood spots

    DEFF Research Database (Denmark)

    Rønn, A M; Lemnge, M M; Angelo, H R

    1995-01-01

    A high-performance liquid chromatography method for the simultaneous analysis of dapsone (DDS), the major metabolite of DDS, monoacetyldapsone (MADDS), and pyrimethamine (PYR) was modified for capillary blood samples obtained by finger prick and dried on filter paper. Limit of quantitation using...

  9. Nitrate and nitrite content in bottled beverages by ion-pair high-performance liquid chromatography.

    Science.gov (United States)

    Song, Yang; Deng, Gui-Fang; Xu, Xiang-Rong; Chen, Yong-Hong; Chen, Feng; Li, Hua-Bin

    2013-01-01

    Nitrate and nitrite levels in six types of beverages--total of 292 individual samples from 73 brands (four bottles each)--from Guangzhou city in China were evaluated by ion-pair high-performance liquid chromatography. All samples contained nitrate. Nitrate and nitrite ranges were 0.43-46.08 and beverages.

  10. Analysis of carprofen dosage forms and drug substance by high-performance liquid chromatography.

    Science.gov (United States)

    Ross, A J; Del Mauro, M D; Sokoloff, H K; Casey, D L

    1984-09-01

    A high-performance liquid chromatographic method for the analysis of carprofen in solid dosage forms and as the bulk drug substance was developed. The simple, accurate, reproducible, and stability-indicating method was shown to be applicable to drug substance and dosage form stability studies, as well as the quality control of carprofen dosage forms.

  11. Comparison of ultra high performance supercritical fluid chromatography, ultra high performance liquid chromatography, and gas chromatography for the separation of synthetic cathinones.

    Science.gov (United States)

    Carnes, Stephanie; O'Brien, Stacey; Szewczak, Angelica; Tremeau-Cayel, Lauriane; Rowe, Walter F; McCord, Bruce; Lurie, Ira S

    2017-09-01

    A comparison of ultra high performance supercritical fluid chromatography, ultra high performance liquid chromatography, and gas chromatography for the separation of synthetic cathinones has been conducted. Nine different mixtures of bath salts were analyzed in this study. The three different chromatographic techniques were examined using a general set of controlled synthetic cathinones as well as a variety of other synthetic cathinones that exist as positional isomers. Overall 35 different synthetic cathinones were analyzed. A variety of column types and chromatographic modes were examined for developing each separation. For the ultra high performance supercritical fluid chromatography separations, analyses were performed using a series of Torus and Trefoil columns with either ammonium formate or ammonium hydroxide as additives, and methanol, ethanol or isopropanol organic solvents as modifiers. Ultra high performance liquid chromatographic separations were performed in both reversed phase and hydrophilic interaction chromatographic modes using SPP C18 and SPP HILIC columns. Gas chromatography separations were performed using an Elite-5MS capillary column. The orthogonality of ultra high performance supercritical fluid chromatography, ultra high performance liquid chromatography, and gas chromatography was examined using principal component analysis. For the best overall separation of synthetic cathinones, the use of ultra high performance supercritical fluid chromatography in combination with gas chromatography is recommended. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Injection-ultrasound-assisted emulsification microextraction based on using low-density organic solvent followed by high-performance liquid chromatography for the determination of pyrethroids in water samples.

    Science.gov (United States)

    Xu, Kailin; Liang, Bing; Li, Yanfang; Cheng, Yuan; Feng, Yuyan

    2013-02-21

    A highly efficient, simple and rapid method, injection-ultrasound-assisted emulsification microextraction based on using low-density organic solvents followed by high-performance liquid chromatography-ultraviolet detection, was developed for the determination of trace level pyrethroids in water samples. Various parameters influencing the extraction efficiency, such as type of extractant, extractant volume, ultrasonic time, centrifugation time and salt addition, were studied and optimized by two methods: the single factor experiment and the Box-Behnken design. Under the optimum conditions, great enrichment factors (678-713) and good recoveries (92.48-97.31%) were obtained for the extraction and analysis of artificial water samples. Linearity of the method for three pyrethroids was in the range of 0.11-218 μg L(-1) for fenpropathrin, and 0.07-136 μg L(-1) for fenvalerate and permethrin, respectively, with correlation coefficients ranging from 0.9994 to 0.9999. The limits of detection for the target analytes were 12.13 to 20.16 ng L(-1), and the limits of quantification were 40.43 to 67.19 ng L(-1). The recoveries of the three pyrethroids from actual water samples at three spiked levels were in the range of 83.25 to 103.3% with relative standard deviation RSDs less than 7.40%.

  13. Simultaneous determination of polar and apolar compounds in environmental samples by a polyaniline/hydroxyl multi-walled carbon nanotubes composite-coated stir bar sorptive extraction coupled with high performance liquid chromatography.

    Science.gov (United States)

    Hu, Cong; He, Man; Chen, Beibei; Hu, Bin

    2015-05-15

    Developing novel coatings for stir bar sorptive extraction (SBSE) is essential for extending the application of SBSE. Herein, a polyaniline/hydroxyl multi-walled carbon nanotubes (PANi/MWCNTs-OH) composite-coated stir bar was prepared via the adhesion technique for the simultaneous extraction of polar and apolar compounds, and a novel method of PANi/MWCNTs-OH-coated SBSE coupled with high performance liquid chromatography-ultraviolet detection (HPLC-UV) was proposed. To test the extraction performance of PANi/MWCNTs-OH-coated stir bar, phenols, non-steroidal anti-inflammatory drugs, and polychlorinated biphenyls were selected as representatives for polar, semi-polar and apolar compounds, respectively. High enrichment factors (EFs) ranged from 20.4 to 60.4-fold (theoretical EF, 100-fold) for target analytes were achieved, indicating that the proposed method is applicable in simultaneous analysis of the compounds with different polarities. The prepared PANi/MWCNTs-OH-coated stir bar has a good preparation reproducibility and can be reused for 20 times. The limits of detection (LODs, S/N=3) were found to be in the range of 0.09-0.81μg/L. To validate the applicability, the proposed method was successfully applied to the analysis of eight target analytes in Yangtze River water after filtration and in the extract from sediment samples. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. Improved method for the determination of the cortisol production rate using high-performance liquid chromatography and liquid scintillation counting

    NARCIS (Netherlands)

    van Ingen, H. E.; Endert, E.

    1988-01-01

    Two new methods for the determination of the cortisol production rate using reversed-phase high-performance liquid chromatography are described. One uses ultraviolet detection at 205 nm, the other on-line post-column derivatization with benzamidine, followed by fluorimetric detection. The specific

  15. Simultaneous high-performance liquid chromatographic determination of suxibuzone and its metabolites in plasma and urine.

    Science.gov (United States)

    Marunaka, T; Shibata, T; Minami, Y; Umeno, Y; Shindo, T

    1980-11-01

    A high-performance liquid chromatographic method is described for the simultaneous determination of the anti-inflammatory agent suxibuzone and its metabolites, 4-hydroxymethylphenylbutazone, phenylbutazone, oxyphenbutazone, and gamma-hydroxyphenylbutazone, in plasma and urine. Acidified plasma or urine is extracted with benzenecyclohexane (1:1). The organic extract is reduced to dryness and the resulting residue is redissolved in methanol. Aliquots of this solution are chromatographed on a reversed-phase column using a mobile phase of methanol--0.5 M KH2PO4 (linear gradient from 0 to 100% methanol at 8% min with a flow rate of 2.0 ml/min) on a high-performance liquid chromatograph equipped with a UV absorbance detector (254 nm). Detection is limited to 0.10 microgram/ml for suxibuzone and 4-hydroxymethylphenylbutazone and to 0.05 microgram/ml for the other metabolites.

  16. Analysis of drugs of abuse in human plasma by dispersive liquid-liquid microextraction and high-performance liquid chromatography.

    Science.gov (United States)

    Fernández, P; Regenjo, M; Bermejo, A M; Fernández, A M; Lorenzo, R A; Carro, A M

    2015-04-01

    Opioids and cocaine are widely used at present, both for recreational purposes and as drugs of abuse. This raises the need to develop new analytical methods specifically designed for the simultaneous detection of several drugs of abuse in biological samples. In this work, dispersive liquid-liquid microextraction (DLLME) was assessed as a new sample treatment for the simultaneous extraction of morphine (MOR), 6-acetylmorphine (6AM), cocaine (COC), benzoylecgonine (BZE) and methadone (MET) from human plasma. Preliminary assays were done before developing an experimental design based on a Uniform Network Doehlert which allowed the optimum extraction conditions to be identified, namely: a volume of extractant solvent (chloroform) and dispersant solvent (acetonitrile) of 220 µl and 3.2 ml, respectively; 0.2 g of NaCl as a salting-out additive; pH 10.6 and ultrasound stirring for 3.5 min. The resulting extracts were analyzed by high-performance liquid chromatography with photodiode array detection (HPLC-PDA), using an XBridge® RP18 column (250 × 4.6 mm i.d., 5 µm particle size). Calibration graphs were linear over the concentration range 0.1-10 µg ml⁻¹, and detection limits ranged from 13.9 to 28.5 ng ml⁻¹. Precision calculated at three different concentration levels in plasma was included in the range 0.1-6.8% RSD. Recoveries of the five drugs were all higher than 84% on average. Finally the proposed method was successfully applied to 22 plasma samples from heroin, cocaine and/or methadone users, and the most frequently detected drug was benzoylecgonine, followed by methadone, cocaine and morphine. Copyright © 2014 John Wiley & Sons, Ltd.

  17. Determination of food preservatives and saccharin by high-performance liquid chromatography.

    Science.gov (United States)

    Leuenberger, U; Gauch, R; Baumgartner, E

    1979-05-21

    The quantitative analysis of benzoic and sorbic acid, methyl, ethyl and propyl esters of p-hydroxybenzoic acid and saccharin in foodstuffs is described. These compounds are quantitatively extracted with disposable clean-up columns packed with Extrelut and simultaneously determined by high-performance liquid chromatography on reversed-phase columns. Complicated matrices such as cheese, cake, ketchup and chocolate were tested and recoveries were generally better than 95% in the concentration ranges normally used in the food industry.

  18. Simple high-performance liquid chromatographic method to analyse megazol in human and rat plasma

    OpenAIRE

    Enanga, Bertin; Labat, Christian; Boudra, Hamid; Chauvière, G; Keita, M; Bouteille, B.; Dumas, Michel; Houin, Georges

    1997-01-01

    A simple and sensitive high-performance liquid chromatographic method has been developed to measure megazol in human plasma. The method was optimized and validated according to the Washington Concensus Conference on the Validation of Analytical Methods (V.P. Shah et al., Eur. J. Drug Metab. Pharmacokinet., 15 (1991) 249). The criteria of complete validation were specificity, linearity, precision, analytical recovery, dilution and stability. It involved extraction of the plasma with dichlorome...

  19. High-performance liquid chromatography for assaying NAD glycohydrolase from Neurospora crassa conidia.

    Science.gov (United States)

    Pietta, P; Pace, M; Menegus, F

    1983-06-01

    A rapid and sensitive high-performance liquid chromatographic technique was developed to determinate NAD glycohydrolase (EC 3.2.2.5.) activity from Neurospora crassa conidia. The separation of the assay substrate and products was achieved by isocratic reverse-phase chromatography and the peaks were detected by the absorbance at 259 nm. Quantities of NAD+ and nicotinamide as small as 10 pmol could be measured.

  20. Serum Protein Profile Study of Clinical Samples Using High Performance Liquid Chromatography-Laser Induced Fluorescence

    DEFF Research Database (Denmark)

    Karemore, Gopal Raghunath; Ukendt, Sujatha; Rai, Lavanya

    2009-01-01

    The serum protein profiles of normal subjects, patients diagnosed with cervical cancer, and oral cancer were recorded using High Performance Liquid Chromatography combined with Laser Induced Fluorescence detection (HPLC-LIF). Serum protein profiles of the above three classes were tested...... for establishing the ability of HPLC-LIF protein profiling technique for discrimination, using hard clustering and Fuzzy clustering methods. The clustering algorithms have quite successfully classified the profiles as belonging to normal, cancer of cervix, and oral cancer conditions....

  1. Instrumental liquid chromatography: a practical manual on high-performance liquid chromatographic methods

    National Research Council Canada - National Science Library

    Parris, N. A

    1976-01-01

    Available texts on liquid chromatography have tended to emphasize the developments in the theoretical understanding of the technique and methodology or to list numerous applications, complete with experimental details...

  2. Quantitative analysis of benzodiazepines in vitreous humor by high-performance liquid chromatography

    Directory of Open Access Journals (Sweden)

    Elham Bazmi

    2016-08-01

    Full Text Available Objective: Benzodiazepines are frequently screened drugs in emergency toxicology, drugs of abuse testing, and in forensic cases. As the variations of benzodiazepines concentrations in biological samples during bleeding, postmortem changes, and redistribution could be biasing forensic medicine examinations, hence selecting a suitable sample and a validated accurate method is essential for the quantitative analysis of these main drug categories. The aim of this study was to develop a valid method for the determination of four benzodiazepines (flurazepam, lorazepam, alprazolam, and diazepam in vitreous humor using liquid–liquid extraction and high-performance liquid chromatography. Methods: Sample preparation was carried out using liquid–liquid extraction with n-hexane: ethyl acetate and subsequent detection by high-performance liquid chromatography method coupled to diode array detector. This method was applied to quantify benzodiazepines in 21 authentic vitreous humor samples. Linear curve for each drug was obtained within the range of 30–3000 ng/mL with coefficient of correlation higher than 0.99. Results: The limit of detection and quantitation were 30 and 100 ng/mL respectively for four drugs. The method showed an appropriate intra- and inter-day precision (coefficient of variation < 10%. Benzodiazepines recoveries were estimated to be over 80%. The method showed high selectivity; no additional peak due to interfering substances in samples was observed. Conclusion: The present method was selective, sensitive, accurate, and precise for the quantitative analysis of benzodiazepines in vitreous humor samples in forensic toxicology laboratory.

  3. Determination of prostaglandin analogs in cosmetic products by high performance liquid chromatography with tandem mass spectrometry.

    Science.gov (United States)

    Wittenberg, James B; Zhou, Wanlong; Wang, Perry G; Krynitsky, Alexander J

    2014-09-12

    A method was developed and validated for the determination of 16 prostaglandin analogs in cosmetic products. The QuEChERS (Quick, Easy, Cheap, Efficient, Rugged, Safe) liquid-liquid extraction method, typically used for pesticide residue analysis, was utilized as the sample preparation technique. The prostaglandin analogs were chromatographically separated and quantified using high performance liquid chromatography with tandem mass spectrometry (HPLC-MS/MS). Thirty-one cosmetic products were surveyed, and 13 products were determined to contain a prostaglandin analog with amounts ranging from 27.4 to 297μg/g. The calculated concentrations for the cosmetic products were in a similar range when compared to the concentrations of three different prostaglandin analog-containing prescription products. Copyright © 2014 Elsevier B.V. All rights reserved.

  4. High-Performance Liquid Chromatographic and High-Performance Thin-Layer Chromatographic Method for Quantitative Estimation of Dolutegravir Sodium in Bulk Drug and Pharmaceutical Dosage Form

    OpenAIRE

    Bhavar, Girija B.; Sanjay S. Pekamwar; Aher, Kiran B.; Thorat, Ravindra S.; Chaudhari, Sanjay R.

    2015-01-01

    Simple, sensitive, precise, and specific high-performance liquid chromategraphic (HPLC) and high-performance thin-layer chromatographic (HPTLC) methods for the determination of dolutegravir sodium in bulk drug and pharmaceutical dosage form were developed and validated. In the HPLC method, analysis of the drug was carried out on the ODS C18 column (150 ? 4.6 mm, 5 ?m particle size) using a mixture of acetonitrile: water (pH 7.5) in the ratio of 80:20 v/v as the mobile phase at the flow rate 1...

  5. Determination of Duloxetine and Its Major Metabolites in Rabbit Plasma by High-Performance Liquid Chromatography

    OpenAIRE

    T. K. Laha; S. Sen; G. Mishra

    2015-01-01

    A rapid and sensitive high performance liquid chromatographic method is described for simultaneous determination of duloxetine and its major metabolites, such as 4- hydroxy duloxetine (M7), Glucuronide conjugate of 5-hydroxy-6-methoxy duloxetine (M6) and Glucuronide conjugate of dihydrodiol duloxetine (M12) in rabbit plasma. HPLC analysis was carried out on a µ-Bondapak C18 column (250 mm × 4.6 mm, 5µm particle size) using methanol: phosphate buffer (pH 7.9, 50 mM) (7:3 v/v) as the mobile pha...

  6. Detection of cheese whey and caseinomacropeptide in fermented milk beverages using high performance liquid chromatography

    OpenAIRE

    E.H.P. Andrade; M.R. Souza; L.M. Fonseca; C.F.A.M. Penna; M.M.O.P. Cerqueira; T. Roza; B. Seridan; M.F.S. Resende; F.A. Pinto; C.N.B.C. Villanoeva; M.O. Leite

    2014-01-01

    Cheese whey level and caseinomacropeptide (CMP) index of fermented milk beverages added with four levels of cheese whey (0, 10, 20, and 40%) and stored at 8-10oC for 0, 7, 14 and 21 days were determined by high performance liquid chromatography-gel filtration (HPLC-GF). Additionally, the interference of the starter culture and the storage time on the detection of cheese whey and CMP were investigated. Refrigerated storage up to 21 days did not affect (P>0.05) cheese whey and CMP amounts in mi...

  7. High-performance liquid chromatographic determination of molluscicidal saponins from Phytolacca dodecandra (Phytolaccaceae).

    Science.gov (United States)

    Slacanin, I; Marston, A; Hostettmann, K

    1988-09-02

    A high-performance liquid chromatographic method is described for the determination of oleanane saponins in Phytolacca dodecandra (Phytolaccaceae), a plant with potent molluscicidal properties. The molluscicidal monodesmosidic saponins of the berries were determined at 254 nm as their 4-bromophenacyl derivatives, whereas the non-derivatized bidesmosidic saponins, lacking a free carboxyl group, were determined at 206 nm. A comparison of different extraction procedures showed that with cold water predominantly monodesmosidic saponins were obtained, whereas hot water gave mainly bidesmosidic (non-molluscicidal) saponins.

  8. Study of Saiga Horn Using High-Performance Liquid Chromatography with Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Kateřina Mikulíková

    2012-01-01

    Full Text Available The saiga horns have been investigated the using of modern analytic methods. High-performance liquid chromatography (HPLC with mass-spectrometric (MS and MS/MS detection and polyacrylamide gel electrophoresis (PAGE were used. It could be concluded that basic proteins of the saiga horns are keratins and collagen. The basic representation protein in all samples is keratin type I microfibrillar (from sheep, keratin type II microfibrillar (from sheep, collagen type I (α1 (from bovine and collagen type I (α2 (from bovine. Free amino acids we determined in all samples are nontreated by enzyme.

  9. Determination of Niacinamide in Lotions and Creams Using Liquid-Liquid Extraction and High-Performance Liquid Chromatography

    Science.gov (United States)

    Usher, Karyn M.; Simmons, Carolyn R.; Keating, Daniel W.; Rossi, Henry F., III

    2015-01-01

    Chemical separations are an important part of an undergraduate chemistry curriculum. Sophomore students often get experience with liquid-liquid extraction in organic chemistry classes, but liquid-liquid extraction is not as often introduced as a quantitative sample preparation method in honors general chemistry or quantitative analysis classes.…

  10. [Isolation of toxic peptides from Amanita phalloides and their analysis using high-performance liquid chromatography].

    Science.gov (United States)

    Hampl, J

    1993-08-05

    The objective of the work is isolation of toxic peptides from Amanita phalloides--amatoxins (alfa-, beta-, gamma-amanitin) and phallotoxins (phalloidin, phallacidin, phallisin, phallisacin) by liquid chromatography on Sephadex LH-20 according to Yocum modification. Seven main toxins were isolated in centigram amounts. The purity of the toxins isolated was verified by the characteristics of their absorbance spectra, by thin layer chromatography (TLC) and high-performance liquid chromatography on reversed phase (RP-HPLC). The fraction of acid phallotoxins which appears homogenous in TLC and Sephadex LH-20 was separated into 5 substances (four of which are phallotoxins) by preparative RP-HPLC technique. The toxins isolated are sufficiently pure to be used as standards in HPLC.

  11. Determination of metal ions by high-performance liquid chromatographic separation of their hydroxamic acid chelates

    Energy Technology Data Exchange (ETDEWEB)

    Palmieri, M.D.; Fritz, J.S.

    1987-09-15

    Metal ions are determined by adding N-methylfurohydroxamic acid to an aqueous sample and then separating the metal chelates by direct injection onto a liquid chromatographic column. Separations on a C/sub 8/ silica column and a polystyrene-divinylbenzene column are compared, with better separations seen on the polymeric column. The complexes formed at low pH values are cationic and are separated by an ion pairing mechanism. Retention times and selectivity of the metal complexes can be varied by changing the pH. Several metal ions can be separated and quantified; separation conditions, linear calibration curve ranges, and detection limits are presented for Zr(IV), Hf(IV), Fe(III), Nb(V), Al(III), and Sb(III). Interferences due to the presence of other ions in solution are investigated. Finally, an antiperspirant sample is analyzed for zirconium by high-performance liquid chromatography.

  12. Separative determination of ascorbic acid and erythorbic acid by high-performance liquid chromatography.

    Science.gov (United States)

    Arakawa, N; Otsuka, M; Kurata, T; Inagaki, C

    1981-01-01

    High-performance liquid chromatography (HPLC) was applied to the determination of ascorbic acid (AsA) and erythorbic acid (ErA). The apparatus was a Shimadzu model LC-2P Liquid Chromatograph equipped with a UV detector set at 254 nm. The separation was achieved on a LiChrosorb-NH2 column which was pre-treated with 0.1 M ammonium monophosphate solution using a mixture of acetonitrile, acetic acid and water (87:2:11, v/v) as an eluant. The HPLC method has the following advantages: AsA and ErA are quantitated after being distinctly separated, analysis time per one sample is short, and AsA or ErA levels as low as 1.0 X 10(-2) microgram are detectable. Recovery experiments with dehydro-AsA and dehydro-ErA, involving reduction with H2S, give satisfactory results.

  13. Quantification of Quercetin and Rutin from Benincasa hispida Seeds and Carissa Congesta Roots by High-performance Thin Layer Chromatography and High-performance Liquid Chromatography.

    Science.gov (United States)

    Doshi, Gaurav Mahesh; Une, Hemant Devidas

    2016-01-01

    In Indian Ayurvedic system, Benincasa hispida (BH) and Carissa congesta (CC) are well-known plants used for major and minor ailments. BH has been regarded as Kushmanda, whereas CC has been used in immune-related disorders of the human system. Quercetin and rutin identified from the vast plethora of plant extracts have proved to possess ethnopharmacological relevance. In present studies, we have determined quercetin and rutin in terms of percentage in BH seeds and CC roots by high-performance thin layer chromatography (HPTLC) and high-performance liquid chromatography (HPLC). After extraction and phytochemical screening, the extracts were subjected to quantification for the presence of quercetin and rutin by HPTLC and HPLC. HPTLC showed quercetin as 44.60, 27.13% and rutin as 32.00, 36.31% w/w, whereas HPLC revealed quercetin as 34.00, 35.00% and rutin as 21.99, 45.03% w/v in BH and CC extracts, respectively. The BH and CC extracts have elucidated peaks that were corresponding with standard peaks on undertaking chromatographic studies. Quercetin and rutin are isolated from BH seeds and CC roots by High Performance. Thin Layer Chromatography and High Performance Liquid Chromatography. HPTLC revealed presence of quercetin as 44.60, 27.13 % and rutin as 32.00, 36.31 % w/w. HPLC revealed presence of quercetin as 34.00, 35.00 % and rutin as 21.99, 45.03 % w/v. Abbreviation Used: HPTLC: High Performance Thin Layer Chromatography; HPLC: High Pressure Liquid Chromatography, UV: Ultraviolet, CC: Carissa congesta, BH: Benincasa hispida.

  14. Feeding of liquid silicon for high performance multicrystalline silicon with increased ingot height and homogenized resistivity

    Science.gov (United States)

    Krenckel, Patricia; Riepe, Stephan; Schindler, Florian; Strauch, Theresa

    2017-04-01

    Feeding of liquid silicon during the directional solidification process is a promising opportunity for cost reduction by increased throughput and improved material homogeneity due to constant resistivity over ingot height. In this work, a liquid feeding apparatus was developed for an industrial type directional solidification furnace. One n-type G2 sized High Performance multicrystalline ingot with liquid feeding of additional 14 kg of undoped silicon feedstock was crystallized. The resistivity was kept within a range of ±0.1 Ω cm of the target resistivity during the feeding sequence. A smaller mean grain area growth was observed during feeding, whereas the area fraction of recombination active dislocation structures was as low as in a reference ingot. Increased interstitial oxygen and substitutional carbon concentrations were measured for the ingot with liquid feeding. The measured mean bulk lifetime of 190 μs for passivated wafers in the feeding sequence can probably be increased by further pre-melting crucible improvements. For this laboratory experiment, energy reductions of 2% per wafer and time savings of 16% per wafer were realized.

  15. Comparison of capillary electrophoresis and high performance liquid chromatography methods for caffeine determination in decaffeinated coffee

    Directory of Open Access Journals (Sweden)

    Carolina Schaper Bizzotto

    2013-03-01

    Full Text Available Decaffeinated coffee accounts for 10 percent of coffee sales in the world; it is preferred by consumers that do not wish or are sensitive to caffeine effects. This article presents an analytical comparison of capillary electrophoresis (CE and high performance liquid chromatography (HPLC methods for residual caffeine quantification in decaffeinated coffee in terms of validation parameters, costs, analysis time, composition and treatment of the residues generated, and caffeine quantification in 20 commercial samples. Both methods showed suitable validation parameters. Caffeine content did not differ statistically in the two different methods of analysis. The main advantage of the high performance liquid chromatography (HPLC method was the 42-fold lower detection limit. Nevertheless, the capillary electrophoresis (CE detection limit was 115-fold lower than the allowable limit by the Brazilian law. The capillary electrophoresis (CE analyses were 30% faster, the reagent costs were 76.5-fold, and the volume of the residues generated was 33-fold lower. Therefore, the capillary electrophoresis (CE method proved to be a valuable analytical tool for this type of analysis.

  16. Hb A1c Separation by High Performance Liquid Chromatography in Hemoglobinopathies

    Directory of Open Access Journals (Sweden)

    Vani Chandrashekar

    2016-01-01

    Full Text Available Hb A1c measurement is subject to interference by hemoglobin traits and this is dependent on the method used for determination. In this paper we studied the difference between Hb A1c measured by HPLC in hemoglobin traits and normal chromatograms. We also studied the correlation of Hb A1c with age. Hemoglobin analysis was carried out by high performance liquid chromatography. Spearman’s rank correlation was used to study correlation between A1c levels and age. Mann-Whitney U test was used to study the difference in Hb A1c between patients with normal hemoglobin and hemoglobin traits. A total of 431 patients were studied. There was positive correlation with age in patients with normal chromatograms only. No correlation was seen in Hb E trait or beta thalassemia trait. No significant difference in Hb A1c of patients with normal chromatograms and patients with hemoglobin traits was seen. There is no interference by abnormal hemoglobin in the detection of A1c by high performance liquid chromatography. This method cannot be used for detection of A1c in compound heterozygous and homozygous disorders.

  17. Simple high-performance liquid chromatographic method to analyse megazol in human and rat plasma.

    Science.gov (United States)

    Enanga, B; Labat, C; Boudra, H; Chauvière, G; Keita, M; Bouteille, B; Dumas, M; Houin, G

    1997-08-29

    A simple and sensitive high-performance liquid chromatographic method has been developed to measure megazol in human plasma. The method was optimized and validated according to the Washington Concensus Conference on the Validation of Analytical Methods (V.P. Shah et al., Eur. J. Drug Metab. Pharmacokinet., 15 (1991) 249). The criteria of complete validation were specificity, linearity, precision, analytical recovery, dilution and stability. It involved extraction of the plasma with dichloromethane, followed by reversed-phase high-performance liquid chromatography using a Kromasil C8 column and UV detection at 360 nm. The retention times of the internal standard (tinidazol) and megazol were 6.10 and 9.60 min, respectively. The standard curve was linear from 2 ng ml-1 (limit of quantification) to 2000 ng ml-1. The coefficients of variation for all the criteria of validation were less than 6%; 85 to 92% extraction efficiencies were obtained. Megazol was stable during the storage period (one month at -20 degrees C) in plasma and for two months at 25 degrees C in standard solution. The method was tested by measuring the plasma concentration following oral administration to rat and was shown to be suitable for pharmacokinetic studies.

  18. Unconventional High-Performance Laser Protection System Based on Dichroic Dye-Doped Cholesteric Liquid Crystals

    Science.gov (United States)

    Zhang, Wanshu; Zhang, Lanying; Liang, Xiao; Le Zhou; Xiao, Jiumei; Yu, Li; Li, Fasheng; Cao, Hui; Li, Kexuan; Yang, Zhou; Yang, Huai

    2017-02-01

    High-performance and cost-effective laser protection system is of crucial importance for the rapid advance of lasers in military and civilian fields leading to severe damages of human eyes and sensitive optical devices. However, it is crucially hindered by the angle-dependent protective effect and the complex preparation process. Here we demonstrate that angle-independence, good processibility, wavelength tunability, high optical density and good visibility can be effectuated simultaneously, by embedding dichroic anthraquinone dyes in a cholesteric liquid crystal matrix. More significantly, unconventional two-dimensional parabolic protection behavior is reported for the first time that in stark contrast to the existing protection systems, the overall parabolic protection behavior enables protective effect to increase with incident angles, hence providing omnibearing high-performance protection. The protective effect is controllable by dye concentration, LC cell thickness and CLC reflection efficiency, and the system can be made flexible enabling applications in flexible and even wearable protection devices. This research creates a promising avenue for the high-performance and cost-effective laser protection, and may foster the development of optical applications such as solar concentrators, car explosion-proof membrane, smart windows and polarizers.

  19. Determination of metformin in human plasma by high-performance liquid chromatography.

    Science.gov (United States)

    Amini, Hossein; Ahmadiani, Abolhassan; Gazerani, Parisa

    2005-09-25

    A simple, selective and sensitive high-performance liquid chromatographic method with spectrophotometric detection was developed for the determination of antihyperglycemic agent metformin in human plasma using a novel sample extraction procedure. Liquid-liquid extraction of metformin and ranitidine (as internal standard) from plasma samples was performed with 1-butanol/n-hexane (50:50, v/v) in alkaline condition followed by back-extraction into diluted acetic acid. Chromatography was carried out using a silica column (250 mmx4.6 mm, 5 microm) under isocratic elution with acetonitrile-40 mM aqueous sodium dihydrogen phosphate (25:75, v/v), pH 6. The limit of quantification (LOQ) was 15.6 ng/ml and the calibration curves were linear up to 2000 ng/ml. The mean absolute recoveries for metformin and internal standard using the present extraction procedure were 98 and 95%, respectively. The intra- and inter-day coefficient of variation and percent error values of the assay method were all less than 8.3%.

  20. Sensitive determination of clarithromycin in human plasma by high-performance liquid chromatography with spectrophotometric detection.

    Science.gov (United States)

    Amini, Hossein; Ahmadiani, Abolhassan

    2005-03-25

    A rapid, selective and sensitive high-performance liquid chromatographic method with spectrophotometric detection was developed for the determination of clarithromycin in human plasma. Liquid-liquid extraction of clarithromycin and norverapamil (as internal standard) from plasma samples was performed with n-hexane/1-butanol (98:2, v/v) in alkaline condition followed by back-extraction into diluted acetic acid. Chromatography was carried out using a CN column (250 mm x 4.6 mm, 5 microm) under isocratic elution with acetonitrile-50 mM aqueous sodium dihydrogen phosphate (32:68, v/v), pH 4.5. Detection was made at 205 nm and analyses were run at a flow-rate of 1.0 ml/min at 40 degrees C. The analysis time was less than 11 min. The method was specific and sensitive with a quantification limit of 31.25 ng/ml and a detection limit of 10 ng/ml in plasma. The mean absolute recovery of clarithromycin from plasma was 95.9%, while the intra- and inter-day coefficient of variation and percent error values of the assay method were all less than 9.5%. Linearity was assessed in the range of 31.25-2000 ng/ml in plasma with a correlation coefficient of greater than 0.999. The method was used to analyze several hundred human plasma samples for bioavailability studies.

  1. High-performance liquid chromatography analysis methods developed for quantifying enzymatic esterification of flavonoids in ionic liquids

    DEFF Research Database (Denmark)

    Lue, Bena-Marie; Guo, Zheng; Xu, X.B.

    2008-01-01

    Methods using reversed-phase high-performance liquid chromatography (RP-HPLC) with ELSD were investigated to quantify enzymatic reactions of flavonoids with fatty acids in the presence of diverse room temperature ionic liquids (RTILs). A buffered salt (preferably triethylamine-acetate) was found...... essential for separation of flavonoids from strongly polar RTILs, whereby RTILs were generally visible as two major peaks identified based on an ion-pairing/exchanging hypothesis. C8 and C12 stationary phases were optimal while mobile phase pH (3-7) had only a minor influence on separation. The method...... developed was successfully applied for primary screening of RTILs (> 20), with in depth evaluation of substrates in 10 RTILs, for their evaluation as reaction media....

  2. Rapid determination of amphotericin B levels in serum by high-performance liquid chromatography without interference by bilirubin.

    OpenAIRE

    Hosotsubo, H; Takezawa, J; Taenaka, N; Hosotsubo, K; Yoshiya, I

    1988-01-01

    A high-performance liquid chromatographic method for the determination of amphotericin B concentrations in human serum without bilirubin interference was developed and compared with a microbiological assay. The high-performance liquid chromatographic assay utilized a reversed-phase trimethyl silica column, simple sample preparation, and visible detection. Reproducibility studies yielded coefficient-of-variation ranges from 1.02 to 2.11% for within-day precision and 2.88 to 4.32% for between-d...

  3. Development of high performance liquid chromatography method for miconazole analysis in powder sample

    Science.gov (United States)

    Hermawan, D.; Suwandri; Sulaeman, U.; Istiqomah, A.; Aboul-Enein, H. Y.

    2017-02-01

    A simple high performance liquid chromatography (HPLC) method has been developed in this study for the analysis of miconazole, an antifungal drug, in powder sample. The optimized HPLC system using C8 column was achieved using mobile phase composition containing methanol:water (85:15, v/v), a flow rate of 0.8 mL/min, and UV detection at 220 nm. The calibration graph was linear in the range from 10 to 50 mg/L with r 2 of 0.9983. The limit of detection (LOD) and limit of quantitation (LOQ) obtained were 2.24 mg/L and 7.47 mg/L, respectively. The present HPLC method is applicable for the determination of miconazole in the powder sample with a recovery of 101.28 % (RSD = 0.96%, n = 3). The developed HPLC method provides short analysis time, high reproducibility and high sensitivity.

  4. High-performance liquid chromatographic determination of biogenic amines in fish implicated in food poisoning.

    Science.gov (United States)

    Hwang, D F; Chang, S H; Shiua, C Y; Chai, T

    1997-05-23

    A rapid, sensitive and reproducible high-performance liquid chromatographic procedure for the determination of nine biogenic amines in fish by improved benzoylation with benzoyl chloride was developed. The benzoylation of amines with benzoyl chloride at 30 degrees C for 40 min was the optimal condition to eliminate the influence of interfering peaks during analysis. The calibration curve for each amine was linear within the range of 0.02-4 microg. The amine recovery from fish meat was better by extraction with 6% trichloroacetic acid than with 1 M HClO4. The application of this method to detect amines in a fried marlin fillet implicated in a food poisoning incident indicated that a high level (84.1 mg/100 g) of histamine was present in the sample.

  5. 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.

  6. Preparation and evaluation of pillararene bonded silica gel stationary phases for high performance liquid chromatography.

    Science.gov (United States)

    Zhao, Wenjie; Chu, Jianxiang; Xie, Fuwei; Duan, Qunpeng; He, Lijun; Zhang, Shusheng

    2017-02-17

    Pillararene bonded stationary phases for high performance liquid chromatography were prepared using 3-aminopropyltriethoxysilane as coupling reagent. The structure of the new materials was characterized by infrared spectroscopy, elemental analysis and thermogravimetric analysis. The chromatographic performance and retention mechanism of the new stationary phases were evaluated in reversed-phase mode compared with C18 using different solute probes including Tanaka test solutes, polycyclic aromatic hydrocarbons, phenols and aromatic positional isomers. The new stationary phases could provide various interactions for different solutes, such as hydrophobic, hydrogen bonding, π-π and inclusion interactions. The synergistic effects resulting from aromatic rings, oxygen atoms, alkyl linkers and cavities in the new host molecules improved the separation selectivity by multiple retention mechanisms. Such hybrid stationary phases can provide more versatility and have great potential for the analysis of complex samples. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Analysis of sulfonated compounds by ion-exchange high-performance liquid chromatography-mass spectrometry.

    Science.gov (United States)

    Socher, G; Nussbaum, R; Rissler, K; Lankmayr, E

    2001-03-30

    Ion-exchange high-performance liquid chromatography (HPIEC)-mass spectrometry (MS) was used for the analysis of different sulfonated compounds. HPIEC was performed on an aminopropyl column applying a gradient with increasing concentration of a buffer consisting of ammonium acetate-acetic acid and acetonitrile as the organic modifier. HPIEC is well suited to highly efficient separation of sulfonated compounds and furthermore, due to the volatility of ammonium acetate, the method is also appropriate for LC-MS coupling by the means of either atmospheric pressure chemical ionization or electrospray ionization. The applicability range of HPIEC-MS is demonstrated on the basis of a complex mixture of model substances consisting of sulfonated aromatics and textile dyes largely differing from each other in their structural properties.

  8. 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.

  9. Core-Shell Columns in High-Performance Liquid Chromatography: Food Analysis Applications

    Directory of Open Access Journals (Sweden)

    Raffaella Preti

    2016-01-01

    Full Text Available The increased separation efficiency provided by the new technology of column packed with core-shell particles in high-performance liquid chromatography (HPLC has resulted in their widespread diffusion in several analytical fields: from pharmaceutical, biological, environmental, and toxicological. The present paper presents their most recent applications in food analysis. Their use has proved to be particularly advantageous for the determination of compounds at trace levels or when a large amount of samples must be analyzed fast using reliable and solvent-saving apparatus. The literature hereby described shows how the outstanding performances provided by core-shell particles column on a traditional HPLC instruments are comparable to those obtained with a costly UHPLC instrumentation, making this novel column a promising key tool in food analysis.

  10. HIGH PERFORMANCE LIQUID CHROMATOGRAPHY METHOD FOR DETERMINATION OF NIFEDIPINE IN HUMAN PLASMA

    Directory of Open Access Journals (Sweden)

    MOHAMMAD ABDOLLAHI

    1999-10-01

    Full Text Available A relatively simple normal phase high performance liquid chromatography (HPLC method was modified for determination of nifedipine in human plasma. The method is based on ultraviolet detection at 235 nm and acidic plasma extraction by a mixture of dichioromethane (30% and n-hexane (70% using nimodipine as an internal standard. The system was stabilized with the use of n-hexane (80%, chloroform (17% and methanol (3% as mobile phase. The assay was linear up to at least 120 ng/ml of nifedipine in plasma. The limit of reliable determination was at least 3 ng/ml plasma. The reproducibility of the method was satisfactory. The procedure can be used effectively to quantitate nifedipine in the human plasma.

  11. [Determination of polysorbates in foods by solid-phase extraction and high-performance liquid chromatography].

    Science.gov (United States)

    Nomura, Chie; Kitagawa, Mikiya; Yoshida, Masaharu; Tanaka, Yukio

    2007-06-01

    A simple and rapid method using refractive index high-performance liquid chromatography (RI-HPLC) was developed for the determination of polysorbates (PS) in processed foods. PS were extracted with ethyl acetate containing 5% methanol. The extract was cleaned up on a multimode cartridge (300 mg) and an Alumina-N cartridge (500 mg) to remove fats and food color. HPLC separation was performed on a C18 column (4.6 i.d. x 150 mm) with methanol as the mobile phase. The recoveries of PS80 from nine kinds of foods fortified at the levels 1-5 g/kg were 80-99%. The limit of quantitation for PS80 in foods was 0.10 g/kg. The proposed method was applied to Worcestershire sauce that was PS-positive by TLC, and PS was confirmed to be present as PS80 at the concentration of 0.13 g/kg.

  12. Simultaneous assay for amatoxins and phallotoxins in Amanita phalloides Fr. by high-performance liquid chromatography.

    Science.gov (United States)

    Enjalbert, F; Gallion, C; Jehl, F; Monteil, H; Faulstich, H

    1992-05-15

    A reversed-phase high-performance liquid chromatographic method is described that allows the simultaneous determination of up to eight amatoxins and phallotoxins. The method identifies both neutral toxins (alpha- and gamma-amanitin, phalloidin, phallisin and phalloin) and acidic toxins (beta-amanitin, phallacidin and phallisacin). Toxins were separated, identified and determined by gradient elution with 0.02 M aqueous ammonium acetate-acetonitrile and simultaneous monitoring of the absorbances at 214 and 295 nm. The assay was successfully applied to the analysis of the toxins in a crude extract of Amanita phalloides. The limit of detection for each toxin was 10 ng/ml of extraction medium. The assay was further validated by analysing the toxin content in Galerina marginata, a species containing only amatoxins. This relatively simple method should be suitable for the detection of amatoxins and phallotoxins in almost any species of mushrooms.

  13. Characterization of nine polyphenols in fruits of Malus pumila Mill by high-performance liquid chromatography

    Directory of Open Access Journals (Sweden)

    Lu Bai

    2016-04-01

    Full Text Available Polyphenols are important bioactive substances in apple. To explore the profiles of the nine representative polyphenols in this fruit, a high-performance liquid chromatography method has been established and validated. The validated method was successfully applied for the simultaneous characterization and quantification of these nine apple polyphenols in 11 apple extracts, which were obtained from six cultivars from Shaanxi Province, China. The results showed that only abscission of the Fuji apple sample was rich in the nine apple polyphenols, and the polyphenol contents of other samples varied. Although all the samples were collected in the same region, the contents of nine polyphenols were different. The proposed method could serve as a prerequisite for quality control of Malus products.

  14. Characterization of nine polyphenols in fruits of Malus pumila Mill by high-performance liquid chromatography.

    Science.gov (United States)

    Bai, Lu; Guo, Sen; Liu, Qingchao; Cui, Xueqin; Zhang, Xinxin; Zhang, Li; Yang, Xinwen; Hou, Manwei; Ho, Chi-Tang; Bai, Naisheng

    2016-04-01

    Polyphenols are important bioactive substances in apple. To explore the profiles of the nine representative polyphenols in this fruit, a high-performance liquid chromatography method has been established and validated. The validated method was successfully applied for the simultaneous characterization and quantification of these nine apple polyphenols in 11 apple extracts, which were obtained from six cultivars from Shaanxi Province, China. The results showed that only abscission of the Fuji apple sample was rich in the nine apple polyphenols, and the polyphenol contents of other samples varied. Although all the samples were collected in the same region, the contents of nine polyphenols were different. The proposed method could serve as a prerequisite for quality control of Malus products. Copyright © 2015. Published by Elsevier B.V.

  15. High-performance liquid chromatography of bile pigments: separation and characterization of the urobilinoids.

    Science.gov (United States)

    Bull, R V; Lim, C K; Gray, C H

    1981-11-20

    The detailed analysis of faecal bile pigments by high-performance liquid chromatography is described. Non-aqueous reversed-phase systems with acetonitrile-dimethyl sulphoxide or acetonitrile-dimethyl sulphoxide-methanol as the mobile phase on C1, C8 or C18-bonded silica are used for the group separation of verdinoids, violinoids and urobilinoids. A silica column, with acetonitrile-water-tetraethylene-pentamine as mobile phase, separates the laevorotatory stercobilin (C33H46N4O6) and half-stercobilin (C33H44N4O6) from the optically inactive urobilin (C33H42N4O6). The diastereoisomers are resolved by converting the urobilinoids into their dimethyl esters before chromatography on a silica column with n-heptane-methyl acetate-methanol containing 1% of diethylamine as the solvent system.

  16. High-performance liquid chromatographic analysis of anthraquinone compounds in the Laurera benguelensis

    Science.gov (United States)

    Manojlović, N.; Marković, Z.; Gritsanapan, W.; Boonpragob, K.

    2009-09-01

    A high-performance liquid chromatographic (HPLC) method has been developed for the characterization of anthraquinone metabolites in extracts of the lichen Laurera benguelensis. With this method four anthraquinone derivatives 1,8-dihydroxy-3-methoxy-6-methylanthraquinone, 1,8-dihydroxy-3-formyl-6-methoxyanthraquinone, 1,8-dihydroxy-3-hydroxymethyl-6-methoxy-anthraquinone and 1,3,8-trihyroxy-6-methylanthraquinone can be analyzed. Components of lichen were detected by characteristic ultraviolet spectra and relative retention times. This is first report of phytochemical analysis of L. benguelensis. Importance of this research is in recognizing some new source (lichen and its extracts) as a natural emplacement of antioxidants because oxidation with free radicals or autooxidation is big problem for preservation of food products.

  17. Use of high-performance liquid chromatography-diode array detection in forensic toxicology.

    Science.gov (United States)

    Koves, E M

    1995-02-10

    A comprehensive approach to the analysis for many drugs in postmortem blood and biological fluids using high-performance liquid chromatography and diode array detection has been developed. To reduce the likelihood of co-eluting interference components of postmortem blood or other drugs, selective back-extraction was also used to screen and quantitate drugs in blood and biofluids. An isocratic mobile phase (acetonitrile, phosphoric acid and triethylamine buffer, pH 3.4) was developed and found stable, reliable and convenient for general drug screening and quantitation. A library of drug spectra in the ultraviolet wavelength range (210-367 nm) was established for 272 drugs on two reversed-phase columns: Supelcosil (biphenyl) and LiChrospher RP-8. The application of several methods to whole blood, the analysis of complex cases and the use of multicomponent analysis for qualitative and quantitative analysis is discussed.

  18. SIMULTANEOUS DETERMINATION OF PARACETAMOL AND IBUPROFENE MIXTURES BY HIGH PERFORMANCE LIQUID CHROMATOGRAPHY

    Directory of Open Access Journals (Sweden)

    Sophi Damayanti

    2010-06-01

    Full Text Available Analytical method for the determination of paracetamol and ibuprofene mixtures has been developed by High Performance Liquid Chromatography using C-18 column and acetinitrile - phosphate buffer pH = 4.5 (75:25 containing 0.075% sodium hexanesulfunate as a mobile phase. The detector was set at 215 nm. Using such conditions, retention time for paracetamol and ibuprofen was 4.89 and 7.11 min, respectively. The recovery for paracetamol and ibuprofen was found to be 101.07± 0.73% and 102.02 ± 1.58%, respectively. The detector limits of the method was 1.30 and 1.60 μg/mL with the relative standard deviation (RSD 0.74 and 1.52% for paracetamol and ibuprofen, respectively.   Keywords: paracetamol, ibuprofen, multi-component, validation, HPLC.

  19. Determination of 1-hydroxypyrene in human urine by high-performance liquid chromatography

    DEFF Research Database (Denmark)

    Hansen, Åse Marie; Poulsen, O M; Christensen, J M

    1993-01-01

    A high-performance liquid chromatography (HPLC)/fluorescence method for quantitative analysis of 1-hydroxypyrene in urine was developed. The method validation analysis showed the method to be in analytical control. No significant systematical errors could be demonstrated. The entire run time....... The developed method is presently used for measurement of 1-hydroxypyrene in urine samples from workers exposed to a low airborne level of polycyclic aromatic hydrocarbons, generally less than 25 micrograms/m3. The urine samples of exposed workers (n = 122) showed a range of 1-hydroxypyrene from the limit...... of chromatography was 10 min using isocratic elution (acetonitrile-water, 70:30), and the retention time for 1-hydroxypyrene was 3.5 min. The short run time in combination with the low limit detection (1.37 nmol/L) makes the method potentially applicable for surveillance of pyrene exposure in work environments...

  20. High-performance liquid chromatography for determination of α-tocopherol in vegetables

    Directory of Open Access Journals (Sweden)

    Marcin Horbowicz

    2013-12-01

    Full Text Available A simple method for the determination of α-tocopherol in vegetables is described. The procedure consists of the following steps: saponification, extraction, silica-column clean-up, and high-performance liquid chromatography. Elution time for D, L-α-tocopherol was 9.0 min using a Zorbax Sil (250 x 4.6 mm column and an isocratic mobile phase of hexane-methanol (99.3 + 0.7, with a flow rate of 1 ml/min, and detection at 292 nm using a variable UV detector. The average recovery of α-tocopherol was 91.2%, and the minimum detectable amount was 0.1 mg/100 g of fresh vegetable tissue. This method is comparable to gas-chromatographic determination of α-tocopherol, but has fewer analytical steps and gives more reproducible results.

  1. Detection of cheese whey and caseinomacropeptide in fermented milk beverages using high performance liquid chromatography

    Directory of Open Access Journals (Sweden)

    E.H.P. Andrade

    2014-06-01

    Full Text Available Cheese whey level and caseinomacropeptide (CMP index of fermented milk beverages added with four levels of cheese whey (0, 10, 20, and 40% and stored at 8-10oC for 0, 7, 14 and 21 days were determined by high performance liquid chromatography-gel filtration (HPLC-GF. Additionally, the interference of the starter culture and the storage time on the detection of cheese whey and CMP were investigated. Refrigerated storage up to 21 days did not affect (P>0.05 cheese whey and CMP amounts in milk (0% of cheese whey and in fermented milk beverages added with 10 and 20% of cheese whey (P>0.05. However, cheese whey and CMP amounts were higher than expected (P<0.05 in fermented milk beverages added with 40% of cheese whey and stored for 21 days.

  2. Analysis of lipophilic pigments from a phototrophic microbial mat community by high performance liquid chromatography

    Science.gov (United States)

    Palmisano, A. C.; Cronin, S. E.; Des Marais, D. J.

    1988-01-01

    As assay for lipophilic pigments in phototrophic microbial mat communities using reverse phase-high performance liquid chromatography was developed which allows the separation of 15 carotenoids and chloropigments in a single 30 min program. Lipophilic pigments in a laminated mat from a commercial salina near Laguna Guerrero Negro, Baja California Sur, Mexico reflected their source organisms. Myxoxanthophyll, echinenone, canthaxanthin, and zeaxanthin were derived from cyanobacteria; chlorophyll c, and fucoxanthin from diatoms; chlorophyll a from cyanobacteria and diatoms; bacteriochlorophylls a and c, bacteriophaeophytin a, and gamma-carotene from Chloroflexus spp.; and beta-carotene from a variety of phototrophs. Sensitivity of detection was 0.6-6.1 ng for carotenoids and 1.7-12 ng for most chloropigments. This assay represents a significant improvement over previous analyses of lipophilic pigments in microbial mats and promises to have a wider application to other types of phototrophic communities.

  3. Rifampicin Interference in the Measurement of Urinary Catecholamines by High-Performance Liquid Chromatography.

    Science.gov (United States)

    Kim, Hyun-Ki; Ko, Dae-Hyun; Jeong, Tae-Dong; Lee, Sang-Hee; Lee, Woochang; Lee, Soo-Youn; Chun, Sail; Song, Junghan; Min, Won-Ki

    2015-01-01

    Measurement of urine and plasma catecholamines and their metabolites are essential for the diagnosis of pheochromocytoma. Here, we report our experience of rifampicin interference in the measurement of urinary catecholamines using high-performance liquid chromatography. During a 1-year period, four patients taking rifampicin showed unusual chromatograms with markedly larger norepinephrine spikes, translating to highly elevated norepinephrine concentrations: 290.2, 720.1, 312.0, and 812.7 μg/L. This interference effect did not occur when samples were prepared using the alumina method, with norepinephrine values decreasing to 26.4, 31.5, 21.9, and 17.2 μg/L. Interference was also absent in data using LC-MS/MS. Clinical laboratories should verify whether rifampicin interferes with test results in their assays, and physicians should be informed that urinary norepinephrine levels can be falsely elevated in patients taking rifampicin. © 2015 by the Association of Clinical Scientists, Inc.

  4. [Determination of aspirin and free salicylic acid in lysinipirine injection by high performance liquid chromatography].

    Science.gov (United States)

    Dong, Yu; Zhao, Yuan-zheng; Zhang, Yi-na

    2002-05-01

    The contents of aspirin and free salicylic acid in lysinipirine injection were determined by high performance liquid chromatography (HPLC). A Hypersil BDS C18 column was used with the mobile phase of methanol-water-acetic acid (35:65:3, volume ratio) and the detection wavelength of 280 nm. The average recoveries of aspirin and salicylic acid added were 99.27% (RSD = 0.8%) and 99.61%(RSD = 1.3%), respectively. The calibration curves had good linearity in the range of 0.028 g/L -0.141 mg/L and 0.77 mg/L -3.85 mg/L, and the correlation coefficients were 0.9999 and 0.9998 for aspirin and salicylic acid respectively.

  5. High-performance liquid chromatographic screening of chlorophyll derivatives produced during fruit storage.

    Science.gov (United States)

    Almela, L; Fernández-López, J A; Roca, M J

    2000-02-18

    Reversed-phase high-performance liquid chromatography with photodiode array and fluorescence detection was applied to the systematic screening of chlorophylls and derivative pigments. The chromatographic procedure proposed made it possible to successfully separate and identify eight chlorophyll derivatives (the a and b forms of chlorophyll, chlorophyllide, pheophytin and pheophorbide) by using a linear gradient of methanol, acetone and ammonium acetate. The method has been routinely applied to study chlorophyll degradation during the postharvest storage of cherimoya (Annona cherimola, Mill.) fruits. The brilliant green colour even at maturity, and its high chlorophyllase and Mg-dechelating activities, indicate that this plant material might be suitable for investigating the as yet not well known chlorophyll breakdown processes.

  6. Denaturing high performance liquid chromatography (DHPLC in detection of microsatellite instability

    Directory of Open Access Journals (Sweden)

    Metka Ravnik-Glavač

    2007-12-01

    Full Text Available Background: Microsatellite instability (MSI is a phenomenon characterized by small deletions or insertions within short tandem repeats in tumour DNA compared to matching normal DNA. MSI analysis is becoming more and more important for detection of hereditary non-polyposis colorectal cancer as well as for sporadic primary colorectal tumours with MSI high phenotype. Use of five quasimonomorphic mononucleotide markers eliminates ultimate need for analysis of germline DNA corresponding to tumour DNA. Here we discuss our method for MSI analysis using denaturating high performance liquid chromatography (DHPLC in combination with quasimonomorphic mononucleotide microsatellite markers in comparison with previously used methods. The method is high-throughput, accurate, quick and cost-effective and suitable for large-scale studies as well as for daily use with smaller numbers of samples.

  7. Determination of primary amino acids in wines by high performance liquid magneto-chromatography.

    Science.gov (United States)

    Barrado, E; Rodriguez, J A; Castrillejo, Y

    2009-05-15

    Eight amino acids (ethanolamine, glycine, alanine, beta-aminobutyric acid, leucine, methionine, histidine and asparagine) were identified and quantified in Spanish wines by high performance liquid magneto-chromatography (HPLMC) with UV-V spectrophotometry. For this method, the amino acids are first complexed with mono(1,10-phenanthroline)-Cu(II) to confer them paramagnetic properties, and then separated by application of a low magnetic field intensity (5.5 mT) to the stationary phase contained in the chromatographic column. Principal components analysis of the results obtained grouped together the wine samples according to their denomination of origin: "Ribera del Duero", "Rueda" or "Rioja" (Spain). Through cluster analysis, a series of correlations was also observed among certain amino acids, and between these groupings and the type of wine. These clusters were found to reflect the role played by the amino acids as primary or secondary nutrients for the bacteria involved in alcoholic and malolactic fermentation.

  8. High performance liquid chromatography method for the determination of cinnamyl alcohol dehydrogenase activity in soybean roots.

    Science.gov (United States)

    dos Santos, W D; Ferrarese, Maria de Lourdes Lucio; Ferrarese-Filho, O

    2006-01-01

    This study proposes a simple, quick and reliable method for determining the cinnamyl alcohol dehydrogenase (CAD; EC 1.1.1.195) activity in soybean (Glycine max L. Merr.) roots using reversed-phase high performance liquid chromatography (RP-HPLC). The method includes a single extraction of the tissue and conduction of the enzymatic reaction at 30 degrees C with cinnamaldehydes (coniferyl or sinapyl), substrates of CAD. Disappearance of the substrates in the reaction mixture is monitored at 340 nm (for coniferaldehyde) or 345 nm (for sinapaldehyde) by isocratic elution with methanol/acetic acid through a GLC-ODS (M) column. This HPLC technique furnishes a rapid and reliable measure of cinnamaldehyde substrates, and may be used as an alternative tool to analyze CAD activity in enzyme preparation without previous purification.

  9. [Separation of enantiomeric labetalol by reversed-phase high performance liquid chromatography].

    Science.gov (United States)

    Zhao, H; Li, H; Qui, Z

    1999-07-01

    A reversed-phase high performance liquid chromatographic method for the separation of labetalol enantiomers was developed. In the method, 2, 3, 4, 6-tetra-O-acetyl-beta-D-glucopyranosyl isothiocyanate (GITC) was chosen as the reagent for pre-column chiral derivatization of labetalol to give four diastereomeric thiourea derivatives. These derivatives were efficiently separated on a Nova-Pak C18 column using V(MeOH):V(0.01 mol.L-1(pH 7.00) H2PO4(-)-HPO(4)2- buffer) = 51:49 as the mobile phase and detected by UV detector at a wavelength of 250 nm or fluorescence detector at lambda ex = 340 nm and lambda em = 440 nm. The effects of the pH of mobile phase on the retention and fluorescence absorbance are also discussed.

  10. Ionic liquid-based air-assisted liquid-liquid microextraction followed by high performance liquid chromatography for the determination of five fungicides in juice samples.

    Science.gov (United States)

    You, Xiangwei; Chen, Xiaochu; Liu, Fengmao; Hou, Fan; Li, Yiqiang

    2018-01-15

    A novel and simple ionic liquid-based air-assisted liquid-liquid microextraction technique combined with high performance liquid chromatography was developed to analyze five fungicides in juice samples. In this method, ionic liquid was used instead of a volatile organic solvent as the extraction solvent. The emulsion was formed by pulling in and pushing out the mixture of aqueous sample solution and extraction solvent repeatedly using a 10mL glass syringe. No organic dispersive solvent was required. Under the optimized conditions, the limits of detection (LODs) were 0.4-1.8μgL(-1) at a signal-to-noise ratio of 3. The limits of quantification (LOQs) set as the lowest spiking levels with acceptable recovery in juices were 10μgL(-1), except for fludioxonil whose LOQ was 20μgL(-1). The proposed method was applied to determine the target fungicides in juice samples, and acceptable recoveries ranging from 74.9% to 115.4% were achieved. Copyright © 2017. Published by Elsevier Ltd.

  11. Simultaneous quantification of various retinoids by high performance liquid chromatography: its relevance to alcohol research.

    Science.gov (United States)

    Yokoyama, H; Matsumoto, M; Shiraishi, H; Ishii, H

    2000-04-01

    We established a high performance liquid chromatography system that allowed simultaneous quantification of various retinoids. We applied the retinoids to a high performance liquid chromatography system with a silica gel absorption column. Samples were separated by the system with a binary multistep gradient with two kinds of solvent that contained n-Hexan, 2-propanol, and glacial acetic acid in different ratios. Each retinoid was detected at a wavelength of 350 nm. This condition allowed separation of 13-cis-retinoic acid, 9-cis-retinoic acid, all-trans-retinoic acid, 13-cis-retinol, all-trans-retinol, all-trans-4-oxo-retinoic acid, and 13-cis-4-oxo-retinoic acid as distinct single peaks. Each retinoid was also analyzed separately and its retention time determined. To ascertain the reliability of this system for retinoid quantification, retinoids at various concentrations were applied to the system. We observed the linearities between the concentration and area under the curve of the peak for each retinoid by linear least-squares regression analysis up to 2.5 ng/ml for all retinoic acids and up to 5 ng/ml for all retinols. There was no significant scattering in tests of within-day reproducibility or day-to-day reproducibility. Using this system, we examined effects of light exposure on isomerization of retinoids. When retinoids were exposed to room light for 2 hr, the amounts of all but 13-cis-retinol changed significantly. In particular, the amounts of all-trans-retinoic acid and 9-cis-retinoic acid were reduced by 40% and 60%, respectively. The HPLC system established in this study should be useful for studying the oxidation pathway of retinol to retinoic acid. A light-shielded condition is required when particular retinoic acids are analyzed.

  12. High-performance liquid chromatography mass spectrometry of gold and alloy clusters protected by hydrophilic thiolates.

    Science.gov (United States)

    Niihori, Yoshiki; Shima, Daisuke; Yoshida, Kana; Hamada, Kota; Nair, Lakshmi V; Hossain, Sakiat; Kurashige, Wataru; Negishi, Yuichi

    2018-01-25

    In this work, we found two hydrophilic interaction liquid chromatography (HILIC) columns for high-performance liquid chromatography (HPLC) suitable for the high-resolution separation of hydrophilic metal clusters. The mass distributions of the product mixtures of hydrophilic metal clusters were evaluated via HPLC mass spectrometry (LC/MS) using these HILIC columns. Consequently, we observed multiple clusters that had not been previously reported for glutathionate (SG)-protected gold clusters (Aun(SG)m). Additionally, we demonstrated that Aun-xMx(SG)m alloy clusters (M = Ag, Cu, or Pd) in which part of the Au in the Aun(SG)m cluster is replaced by a heteroelement can be synthesized, similar to the case of hydrophobic alloy clusters. It is easy to evaluate the mass distributions of hydrophilic metal clusters using this method. Thus, remarkable progress in the synthesis techniques of hydrophilic metal clusters through the use of this method is anticipated, as is the situation for hydrophobic metal clusters.

  13. Reversed-phase high-performance liquid chromatography of tenuazonic acid and related tetramic acids.

    Science.gov (United States)

    Shephard, G S; Thiel, P G; Sydenham, E W; Vleggaar, R; Marasas, W F

    1991-05-03

    A reversed-phase high-performance liquid chromatographic system for the determination of the fungal toxin, tenuazonic acid, (5S,8S)-3-acetyl-5-sec.-butyltetramic acid, is described. The system utilizes a column packed with deactivated end-capped C18 silica with a high carbon load to overcome the problem of poor chromatographic performance of this beta-diketone on reversed-phase liquid chromatography which previously necessitated the use of anion-exchange, ligand-exchange or ion-pairing methods. The reversed-phase system allows the separation of tenuazonic acid from its (5R,8S)-diastereomer, allo-tenuazonic acid and was applied to the detection of tenuazonic acid in cultures of Alternaria alternata and Phoma sorghina. By means of diode-array ultraviolet detection, (5S)-3-acetyl-5-isopropyltetramic acid was observed in extracts of culture material. This metabolite was purified using the analytical reversed-phase system and was identified by 1H and 13C nuclear magnetic resonance spectroscopy.

  14. Metabolic profiling assisted quality assessment of Rhodiola rosea extracts by high-performance liquid chromatography.

    Science.gov (United States)

    Wang, Zhanguo; Hu, Huiling; Chen, Fang; Zou, Liang; Yang, Mingfu; Wang, Anqi; Foulsham, James E; Lan, Ke

    2012-05-01

    In this work, fast and sensitive high-performance liquid chromatography (HPLC) coupled with multivariate analysis was utilized to assist the quality assessment of Rhodiola rosea extracts (RREs). 131 peaks were separated and detected in RREs on a fused-core C18 column. Principal component analysis (PCA) and hierarchical cluster analysis (HCA) of the chromatographic data demonstrated that 10 batches of RREs could be well-differentiated and categorized into three groups which were closely related to the origins of RREs. Partial least square-discriminant analysis (PLS-DA) showed that the quality differentiation might be explained by at least 6 components, in which rosavin was characterized by an external reference, rosiridine was identified by liquid chromatography-mass spectrometry (LC-MS), and the mass spectra of the others were provided. The observation that the level of rosavin was more relevant to the multivariate chromatographic data than the ones of salidroside and tyrosol, the other two components commonly used to standardize RREs, was confirmed by the PLS prediction models. Results of the present study not only indicated that rosavin was a rational marker to represent the quality of RREs, but also demonstrated the power of HPLC-based metabolic profiling in the quality assessment of herbal extracts. © Georg Thieme Verlag KG Stuttgart · New York.

  15. [Estimation of chloramphenicol in the working area air by high performance liquid chromatography].

    Science.gov (United States)

    Kristova-Bagdasarian, V L; Chokhadzhieva, D

    2008-01-01

    Chloramphenicol (levomycetin) is a broad-spectrum antibiotic that is active against gram-positive and gram-negative microorganisms. At present, it is manufactured via organic synthesis. Working place air becomes polluted during the manufacture and use of medicines containing chloramphenicol. In the working place air, chloramphenicol is present as a disintegration aerosol and may provoke occupational diseases of varying severity in the exposed persons. A procedure has been determined to measure air chloramphenicol, by using high performance liquid chromatography. Aspiration through an AFA FPP-15 aerosol filter is a suitable device for air chloramphenicol sampling. The selected chloramphenicol is removed from the filter via triple methanol extraction in an ultrasound bath. The pooled extract is evaporated to dryness in a current of nitrogen and the dry residue is dissolved in the mobile phase containing acetonitrile : buffer (pH 4.8) = 30:70. The chloramphenicol determination procedure using reverse-phase liquid chromatography with ultraviolet detection at a wavelength of 275 nm has been developed and completely validated. Chromatographic conditions are given. The retention time of chloramphenicol is 6.5 min. The detection limit is 0.1 microg/cm3. The method is noted for a linear relationship between the concentration of chloramphenicol (microg/cm3) and the peak area (mm2) in the range of 1 to 20 microg/cm3.

  16. High-performance liquid-catalyst fuel cell for direct biomass-into-electricity conversion.

    Science.gov (United States)

    Liu, Wei; Mu, Wei; Deng, Yulin

    2014-12-01

    Herein, we report high-performance fuel cells that are catalyzed solely by polyoxometalate (POM) solution without any solid metal or metal oxide. The novel design of the liquid-catalyst fuel cells (LCFC) changes the traditional gas-solid-surface heterogeneous reactions to liquid-catalysis reactions. With this design, raw biomasses, such as cellulose, starch, and even grass or wood powders can be directly converted into electricity. The power densities of the fuel cell with switchgrass (dry powder) and bush allamanda (freshly collected) are 44 mW cm(-2) and 51 mW cm(-2) respectively. For the cellulose-based biomass fuel cell, the power density is almost 3000 times higher than that of cellulose-based microbial fuel cells. Unlike noble-metal catalysts, POMs are tolerant to most organic and inorganic contaminants. Therefore, almost any raw biomass can be used directly to produce electricity without prior purification. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Complementary high performance sensing of gases and liquids using silver nanotube

    Science.gov (United States)

    Isro, Suhandoko D.; Iskandar, Alexander A.; Tjia, May-On

    2017-11-01

    A study on refractive index sensing using a silver nanotube is carried out to investigate the relative advantages of sensing gaseous and liquid samples outside the tube (outer sensing) and inside the core (inner sensing). The geometrical and material parameters of the nanotube are varied to explore the favorable sensing performances covering the range of refractive indices between 1.1 and 1.5. It is shown that the performances at the three sensing points considered are consistently improved with decreased shell thickness and core radius in both sensing modes. While the performance is also monotonously and drastically enhanced with decreased counter permittivity in inner sensing, the similarly large variations in the outer sensing mode are less than strictly consistent. The study further shows that the most favorable FOM values are attained by both sensing modes with 2.5 nm Ag shell thickness and 27.5 nm core radius of the nanotube, whereas the most favorable counter permittivities are different for the two modes. Remarkably, the trend of increasing FOM for samples of lower refractive indices in outer sensing is entirely reversed in inner sensing with roughly the same level of performances. Thus, the core/shell structure of the silver nanotube offers the complementary high performance sensing of gases and liquids using the two sensing modes with appropriately chosen system parameters.

  18. [Determination of phthalic anhydride in ambient air by high performance liquid chromatography].

    Science.gov (United States)

    Zaĭtseva, N V; Ulanova, T S; Karnazhitskaia, T D; Antip'eva, M V; Kislitsina, A V

    2011-01-01

    The paper considers the measurement of phthalic anhydride in the ambient air samples by high performance liquid chromatography. It describes conditions for air sampling and analysis of phthalic anhydride levels in the presence of concomitant components of its production (phthalic and maleic acids, maleic anhydride, etc.) on a liquid chromatograph with an UV detector. The procedure was tested, by estimating the quality of ambient air at the border of a sanitary protection zone of phthalic anhydride production and when analyzing the air in the industrial area. Field studies detected the concentrations of phthalic anhydrate in the air of an enterprise area, which were equal to 0.017-0.115 mg/dm3. Phthalic anhydride was detectable at a concentration of 0.001-0.0021 mg/dm3 at the border of the existing sanitary protection zone in single cases. The procedure has been recommended to measure the mass concentrations of phthalic anhydride aerosol and vapors in ambient air at the reference concentration.

  19. [Measurement of 11 benzophenone ultraviolet-filters in cosmetics by high performance liquid chromatography].

    Science.gov (United States)

    Qu, Baocheng; Bian, Haitao; Mao, Xiqin; Li, Jin

    2015-12-01

    A sample preparation and analytical method with liquid-liquid extraction (LLE) and high performance liquid chromatography (HPLC) was developed to detect 11 benzophenone ultraviolet-filters in cosmetics. The target compounds were extracted by the mixed solutions of tetrahydrofuran (TH)/methanol/water or dichloromethane/water at proper ratios. The extracts were centrifuged and filtered to remove matrix compounds, and then analyzed by HPLC. The separation of analytes was carried out on a Diamonsil-C18 column (150 mm x 4.6 mm, 5 μm) with 0.1% (v/v) formic acid aqueous solution (containing 10 mmol/L ammonium acetate) as mobile phase A and methanol containing 0.1% (v/v) formic acid as mobile phase B. The spiked recoveries of the method (n = 7) were 93.4%-103.8% with the relative standard deviations of 0.1%-4.2%. The limits of detection (LODs) were in the range of 4.0-30 μg/g and the limits of quantitation (LOQs) ranged from 15 to 100 μg/g. The method was applied to the determination of 42 cosmetic samples randomly purchased from the supermarket in Dalian. Five benzophenone series were always detected, in which the content of benzophenone-3 in sunscreen cream and the content of benzophenone-2 in perfume were very high and reached 2 785 μg/g and 2 106 μg/g, respectively. The results showed that the developed method is efficient, reliable and sensitive, which can be applied to the determination of benzophenones in cosmetics.

  20. Determination of insecticides in water using in situ halide exchange reaction-assisted ionic liquid dispersive liquid-liquid microextraction followed by high-performance liquid chromatography.

    Science.gov (United States)

    Li, Songqing; Gao, Haixiang; Zhang, Jiaheng; Li, Yubo; Peng, Bing; Zhou, Zhiqiang

    2011-11-01

    A dispersive liquid-liquid microextraction (DLLME) method using in situ halide exchange reaction to form ionic liquid (IL) extraction phase was developed to determine four insecticides (i.e. methoxyfenozide, tetrachlorvinphos, thiamethoxam, and diafenthiuron) in water samples. The preconcentration procedure, followed by high-performance liquid chromatography and variable wavelength detectors (VWD), enabled the formation of the immiscible IL extraction phase; the insecticides were transferred into the IL phase simultaneously, which enhanced the efficiency and sufficiency, greatly shortening the operation time. The experimental parameters affecting the extraction efficiency including volume of extraction IL, extraction and centrifugation times, volume of the sample solution and exchanging reagent, and addition of organic solvent and salt were investigated and optimized. Under optimized conditions, the extractions yielded recoveries of the target analytes from 82 to 102%. The calibration curves were linear, and the correlation coefficient ranged from 0.9990 to 0.9999 under the concentration levels of 5-200 μg/L. The relative standard deviation (n=6) was 2.9-4.6%. The limits of detection (LODs) for the four insecticides were between 0.98 and 2.54 μg/L. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Ionic-liquid-based dispersive liquid-liquid microextraction coupled with high-performance liquid chromatography for the forensic determination of methamphetamine in human urine.

    Science.gov (United States)

    Wang, Ruifeng; Qi, Xiujuan; Zhao, Lei; Liu, Shimin; Gao, Shuang; Ma, Xiangyuan; Deng, Youquan

    2016-07-01

    Determination of methamphetamine in forensic laboratories is a major issue due to its health and social harm. In this work, a simple, sensitive, and environmentally friendly method based on ionic liquid dispersive liquid-liquid microextraction combined with high-performance liquid chromatography was established for the analysis of methamphetamine in human urine. 1-Octyl-3-methylimidazolium hexafluorophosphate with the help of disperser solvent methanol was selected as the microextraction solvent in this process. Various parameters affecting the extraction efficiency of methamphetamine were investigated systemically, including extraction solvent and its volume, disperser solvent and its volume, sample pH, extraction temperature, and centrifugal time. Under the optimized conditions, a good linearity was obtained in the concentration range of 10-1000 ng/mL with determination coefficient >0.99. The limit of detection calculated at a signal-to-noise ratio of 3 was 1.7 ng/mL and the relative standard deviations for six replicate experiments at three different concentration levels of 100, 500, and 1000 ng/mL were 6.4, 4.5, and 4.7%, respectively. Meanwhile, up to 220-fold enrichment factor of methamphetamine and acceptable extraction recovery (>80.0%) could be achieved. Furthermore, this method has been successfully employed for the sensitive detection of a urine sample from a suspected drug abuser. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Sensitive determination of nitrophenol isomers by reverse-phase high-performance liquid chromatography in conjunction with liquid-liquid extraction

    Science.gov (United States)

    A method for the highly sensitive determination of 2-, 3- and 4- nitrophenols was developed using reverse-phase high-performance liquid chromatography (RP-HPLC) with a UV photodiode array detector. Using a reverse-phase column and 40% aqueous acetonitrile as an eluent (i.e. isocratic elution), the i...

  3. Determination of diflubenzuron and chlorbenzuron in fruits by combining acetonitrile-based extraction with dispersive liquid-liquid microextraction followed by high-performance liquid chromatography.

    Science.gov (United States)

    Ruan, Chunqiang; Zhao, Xiang; Liu, Chenglan

    2015-09-01

    In this study, a simple and low-organic-solvent-consuming method combining an acetonitrile-partitioning extraction procedure followed by "quick, easy, cheap, effective, rugged and safe" cleanup with ionic-liquid-based dispersive liquid-liquid microextraction and high-performance liquid chromatography with diode array detection was developed for the determination of diflubenzuron and chlorbenzuron in grapes and pears. Ionic-liquid-based dispersive liquid-liquid microextraction was performed using the ionic liquid 1-hexyl-3-methylimidazolium hexafluorophosphate as the extractive solvent and acetonitrile extract as the dispersive solvent. The main factors influencing the efficiency of the dispersive liquid-liquid microextraction were evaluated, including the extractive solvent type and volume and the dispersive solvent volume. The validation parameters indicated the suitability of the method for routine analyses of benzoylurea insecticides in a large number of samples. The relative recoveries at three spiked levels ranged between 98.6 and 109.3% with relative standard deviations of less than 5.2%. The limit of detection was 0.005 mg/kg for the two insecticides. The proposed method was successfully used for the rapid determination of diflubenzuron and chlorbenzuron residues in real fruit samples. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Evaluation of aminoacids in irradiated beans (Vigna unguiculata (L.) Walp) by high performance liquid chromatography (HPLC)

    Energy Technology Data Exchange (ETDEWEB)

    Lima, Keila S. Cople; Souza, Luciana B.; Coelho, Maysa J.; Lima, Antonio L. Santos; Hernandes, Nilber K. [Instituto Militar de Engenharia (IME), Rio de Janeiro, RJ (Brazil). Secao de Engenharia Nuclear]. E-mail: keila@ime.eb.br; Godoy, Ronoel L.O. [EMBRAPA Agroindustria de Alimentos, Rio de Janeiro, RJ (Brazil)]. E-mail: ronoel@ctaa.embrapa.br

    2007-07-01

    Fradinho-bean (Vigna unguiculata (L.) Walp) is originated from Africa and is known in Brazil as 'caupi', 'corda' or 'macassar'. It is grown in the interior of Northeast Brazil (semi-arid region) and can be found in parts of the North, being one of the most important components of people's diet in those regions. The Northeast area produces around 429,375 ton of fradinho-bean per year. Leguminous plants are very important sources of proteins, vitamins, carbohydrates and minerals. This kind of bean is an excellent source of proteins (around 23- 25% of its nutritional content), being superior to regular beans (Phaseolus vulgaris). The irradiation process is an alternative to avoid post-harvesting losses, without changing the nutritional value of food. This study has the objective to evaluate the effect of different gamma irradiation doses (0.0; 0.5; 1.0; 2.5; 5.0 and 10.0 kGy) on aminoacid content of fradinho-bean by high performance liquid chromatography (HPLC) and the accompanying of the grains during storage time of 6 months. After irradiation, the bean grains went through a milling process in order to make flour for posterior extraction. A liquid chromatographer Waters, model Alliance 2695, with fluorescent detector Waters 2475, having a mobile phase with gradient elution of sodium acetate. acetonitrile and Milli-Q water, was employed. The flux used was 1 mL/min and the injection volume of 10 {mu}L. The column (C 18 150.0 x 3.9 mm) was kept at 36 deg C. The results show that gamma irradiation is a promise process for fradinho bean during conservation storage time of 6 months, until the dose of 10.0 kGy. Even the most radio-sensitive aminoacids like aromatics and basic lateral chains were preserved. (author)

  5. Comparative in vitro assessment of tolterodine tartrate tablets by high performance liquid chromatographic (HPLC

    Directory of Open Access Journals (Sweden)

    Hossein Danafar

    2016-06-01

    Full Text Available Tolterodine tartrate, is a new, potent and competitive muscarinic receptor antagonist in clinical development for the treatment of urge incontinence and other symptoms of unstable bladder. The purpose of this study is to establish a reliable and quick method for the assignment of tolterodine tartrate by high performance liquid chromatography with ultraviolet detection (HPLC-UV. A rapid  and  sensitive  high  performance  liquid  chromatographic  (HPLC  method  has  been developed  for  determination  of  tolterodine tartrate.  Mobile phase was composed of phosphate acetate 0.1 M (pH 2.5-acetonitrile (50:50 v/v with a flow rate of 1.2 ml/min. The eluted peaks were detected by a UV detector was set at wavelength of 285 nm. The method was validated in the range of tolterodine tartrate concentrations from 10 to 100 µg/ml. The limits of detection (LOD and quantitation (LOQ of the method were 5 and 10 µg/ml, respectively. The average drug recovery was 98.20 % throughout the linear concentration range. The average within-run and between-run accuracy values of 98.56 % and 99.11 % respectively. Statistical  assessment  of  various  in  vitro  dissolution  parameters  and  assay  results was  also  conducted  to  establish  if  there were  any significant difference among them. The validated HPLC method has been used successfully to study tolterodine tartrate.

  6. [Determination of three isothiazolinone biocides in water-borne adhesives by high performance liquid chromatography].

    Science.gov (United States)

    Zhou, Xiao; Li, Xiaolan; Chen, Zhiyan; Ye, Changwen; Zhou, Yun; Meng, Dongling

    2015-01-01

    A rapid high performance liquid chromatography (HPLC) method was developed for the quantitative analysis of three isothiazolinone biocides (2-methyl-4-isothiazolin-3-one (MI), 5-chloro-2-methyl-4-isothiazolin-3-one (CMI) and 1, 2-benzylisothiazolin-3-one (BIT)) in water-borne adhesives. The sample was extracted with methanol-water (1:1, v/v), and purified by centrifugation and filtration. The isothiazolones were separated on a C18 column with methanol-water as mobile phases under gradient elution and detected with a diode array detector (DAD). The pretreatment factors such as extraction solvent, extraction method, dilution ratio, extraction time were optimized. Under the optimized conditions, the targets had good linearities (r2H > or = 0.9992) in the range of 0.25-10.0 mg/L. The recoveries were between 92% and 103% with the relative standard deviations not more than 4%. The limits of detection (LODs) were between 0.43 mg/kg and 1.14 mg/kg. The limits of quantification (LOQs) were between 1.44 mg/kg and 3.81 mg/kg. The results showed that the method can achieve the purpose of quantitative detection. The analyses of real samples verified the reliability of this method.

  7. Determination of the Thermodegradation of deoxyArbutin in Aqueous Solution by High Performance Liquid Chromatography

    Directory of Open Access Journals (Sweden)

    Chih-Chien Lin

    2010-10-01

    Full Text Available Tyrosinase is the key and rate-limiting enzyme responsible for the conversion of tyrosine into melanin. Competitive inhibition of tyrosinase enzymatic activity results in decreased or absent melanin synthesis by melanocytes in human skin. DeoxyArbutin (4-[(tetrahydro-2H-pyran-2-yloxy]phenol, a novel skin whitening agent, was synthesized through the removal of hydroxyl groups from the glucose side-chain of arbutin. DeoxyArbutin not only shows greater inhibition of tyrosinase activity but is also safer than hydroquinone and arbutin. Hence, deoxyArbutin is a potential skin whitening agent for cosmetics and depigmenting drugs; however, stability of this compound under some conditions remains a problem. The lack of stability poses developmental and practical difficulties for the use of deoxyArbutin in cosmetics and medicines. Improving the thermostability of deoxyArbutin is an important issue for its development. In this research, we established an analytical procedure to verify the amount of deoxyArbutin in solutions using a high performance liquid chromatographic (HPLC method. The results indicate that this novel skin whitening agent is a thermolabile compound in aqueous solutions. Additionally, the rate constant for thermodegradation (k and the half-life (t1/2 of deoxyArbutin were determined and can be used to understand the thermodegradation kinetics of deoxyArbutin. This information can aid in the application of deoxyArbutin for many future uses.

  8. Simultaneous quantification of five major biologically active ingredients of saffron by high-performance liquid chromatography.

    Science.gov (United States)

    Li, N; Lin, G; Kwan, Y W; Min, Z D

    1999-07-23

    A simple, sensitive and specific high-performance liquid chromatography-UV (HPLC-UV) method has been developed for the first time to simultaneously quantify the five major biologically active ingredients of saffron, namely crocin 1, crocin 2, crocin 3, crocin 4 and crocetin. Calibration curves were derived by spiking authentic compounds and internal standard, 13-cis-retinoic acid, into herbal samples prior to extraction. Extraction was conducted simply by stirring dried herb (20 mg) with 80% aqueous methanol (5 ml) at ambient temperature in the dark for 2 h. The HPLC assay was performed on a reversed-phase C18 column with linear gradient elution using methanol and 1% aqueous acetic acid. Calibrations were linear (r2 = 0.999) for all five analytes, with overall intra- and inter-day RSDs of less than 11%. The assay was successfully applied to the determination of four crocins and crocetin in three saffron samples and two Zhizi, another crocin-containing herb. Results indicate that the developed HPLC assay can be readily utilized as a quality control method for crocin-containing medicinal herbs.

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

    Directory of Open Access Journals (Sweden)

    Viviane Benevenuti Silva

    2013-09-01

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

  10. Determination of meropenem levels in human serum by high-performance liquid chromatography with ultraviolet detection.

    Science.gov (United States)

    Roth, Thomas; Fiedler, Stella; Mihai, Sidonia; Parsch, Hans

    2017-05-01

    Meropenem is a β-lactam broad-spectrum antibiotic and belongs to the subgroup of carbapenems. It is primarily used in intensive care units for intravenous treatment of severe infections. To avoid bacterial resistance or toxic side effects, the determination of serum meropenem concentration is highly advisable. A simple and fast method for the quantitative determination of meropenem in human serum using high-performance liquid chromatography with ultraviolet detection (HPLC/UV) was developed and validated. Meropenem was determined by an isocratic HPLC using a tris(hydroxymethyl)aminomethane buffer (pH 8.5; 15% methanol) as a mobile phase and UV detection at 300 nm, with a flow rate of 1.0 mL/min and an analysis time of 10 min. Chromatographic separation was performed on a Kinetex C18 column (5 μm, 150 × 4.6 mm). In order to remove undesired serum components, solid-phase extraction was used for sample preparation. Since meropenem is not stable in solution, sample and stock solution were stored at -80°C. After preparation, samples were stable at room temperature for at least 6 h. The calibration curve was linear from 3.5 to 200 mg/L with a correlation coefficient r2 of 0.999. The method is accurate with an intra- and inter-assay precision <18.5%. Copyright © 2016 John Wiley & Sons, Ltd.

  11. Determination of Posaconazole in Plasma/Serum by High-Performance Liquid Chromatography with Fluorescence Detection

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    Peter H. Tang

    2017-05-01

    Full Text Available A sensitive high-performance liquid chromatographic (HPLC method is described for the determination of posaconazole in human plasma/serum. The method is based on a single dilution step by treating the sample with methanol, and followed by the direct injection of the sample into the HPLC system. Posaconazole and internal standard ketoconazole in the methanol extract are subsequently analyzed by using a fluorescence (FL detector at optimized wavelengths (excitation 245 nm and emission 380 nm. The method achieves a linear detector response for peak height measurements over the concentration range of 0.1–10 µg/mL which adequately covers the therapeutic range for appropriate patient monitoring. The chromatographic time is less than 8 min per injection, an improvement over most published HPLC/FL or HPLC/UV methods. The method’s limit of quantitation, linearity, imprecision, and accuracy met all criteria required by the Guidance for Industry Bioanalytical Method Validation. In comparison to other published methods, the current method would be of interest to analytical and clinical laboratories because it employs simple, rapid, and cost-effective procedures.

  12. Comparative determination of phenytoin in plasma by fluorescence polarization immunoassay and high performance liquid chromatography.

    Science.gov (United States)

    Othman, S; al-Turk, W A; Awidi, A S; Daradkeh, T K; Shaheen, O

    1987-09-01

    The need for careful monitoring of plasma concentrations of phenytoin during use of the drug in the treatment of epilepsy is well recognized; there can be great intersubject variation in the absorption rate and clearance rate of the drug, and its therapeutic ratio is narrow. In this study, two methods for determining plasma phenytoin concentrations were compared. One, based on fluorescence polarisation immunoassay (FPIA), is utilised in a commercially-available kit. The other, our own modification of a published procedure, was based on high performance liquid chromatography (HPLC). The accuracy and precision of both methods were evaluated, and the coefficients of variation (C.V.) were calculated. The C.V.'s ranged from 0.71 to 1.86% for the FPIA method, and from 2.81 to 8.69% for the HPLC method. Corresponding bias values were 1.20 to 1.60%, and 2.81 to 8.69%, respectively. A good correlation coefficient (0.977) was obtained, but estimated phenytoin concentrations were significantly higher (95% confidence level) using the HPLC method. We conclude that both methods perform adequately for clinical purposes. The HPLC method is, however, less expensive than the FPIA method.

  13. Synergic Effect of Sulfacetamide and Sulfadiazine in High Performance Liquid Chromatographic Determination of Their Mixture

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    Zahra Ramezani

    2017-02-01

    Full Text Available Background Data accuracy in analytical determination is of prime importance. Antibiotic levels are usually obtained in mixtures using chromatographic techniques. Thus, evaluation of data accuracy in mixtures seems necessary. Objectives The aim of this study was to show how the figure of merits for high performance liquid chromatographic (HPLC determination of sulfacetamide and sulfadiazine changes, while injecting their mixture compared to those injected individually. Methods Standard solutions of the mixture of 2 selected sulfonamides as well as each individual solution were injected on ODS2 C18 (250 × 4.6 mm, 5 µm column. In each case, linear range, limit of detection, and recovery were evaluated. Results Three linear ranges with different sensitivity were observed for both antibiotics, while some that were injected simultaneously compared with those injected separately (just one linear range. The accuracy of the results was compared by both calibration curves (standards injected individually or simultaneously, and suitable calibration methods were introduced. Conclusions More precautions should be taken when determining antibiotics when they present as a mixture. Accordingly, a preliminary study is required to determine the accurate range when analyzing mixtures.

  14. Enantiomeric separation of nonproteinogenic amino acids by high-performance liquid chromatography.

    Science.gov (United States)

    Ilisz, István; Aranyi, Anita; Pataj, Zoltán; Péter, Antal

    2012-12-21

    Amino acids are essential for life, and have many functions in metabolism. One particularly important function is to serve as the building blocks of peptides and proteins, giving rise complex three dimensional structures through disulfide bonds or crosslinked amino acids. Peptides are frequently cyclic and contain proteinogenic as well as nonproteinogenic amino acids in many instances. Since most of the amino acids contain a chiral carbon atom, the stereoisomers of all these amino acids and the peptides in which they are to be found may possess differences in biological activity in living systems. The development of methods for the separation of enantiomers has attracted great interest, since it became evident that the potential biological or pharmacological applications are mostly restricted to one of the enantiomers. The important analytical task of the separation of isomers is achieved mainly by chromatographic and electrophoretic methods. This special review surveys indirect and direct high-performance liquid chromatographic (HPLC) methods of biologically and pharmaceutically important enantiomers of nonproteinogenic amino acids and related compounds, with emphasis on the literature published from the beginning. Copyright © 2012 Elsevier B.V. All rights reserved.

  15. Rapid extraction and high-performance liquid chromatographic determination of parthenolide in feverfew (Tanacetum parthenium).

    Science.gov (United States)

    Zhou, J Z; Kou, X; Stevenson, D

    1999-03-01

    A rapid and sensitive method for quantifying parthenolide in feverfew herb (Tanacetum parthenium) was developed that is significantly faster than those reported in the literature. The extraction system consisted of acetonitrile/water (90:10, v/v) in a bottle with stirring for 30 min. Both Soxhlet and bottle-stirring extractions were studied. Samples were analyzed using high-performance liquid chromatography with a Cosmosil C18-AR column (150 x 4.6 mm, 5 microm, 120 A). The mobile phase consisted of acetonitrile/water (55:45, v/v) with a flow rate of 1.5 mL/min and UV detection at 210 nm. Analysis time was 6 min, with a detection limit of 0.10 ng on column. The calibration curve was linear over a range of 0.160-850 microg/mL parthenolide with R(2) = 0.9999. Replicate tests indicated good reproducibility of the method with an RSD% = 0.88 (n = 10). Spike recovery of parthenolide was found to be 99.3% with an RSD% = 1.6 (n = 6).

  16. Determination of Decabrominated Diphenyl Ether in Soils by Soxhlet Extraction and High Performance Liquid Chromatography

    Science.gov (United States)

    Yang, Xing-Jian; Dang, Zhi; Zhang, Fang-Li; Lin, Zhao-Ying; Zou, Meng-Yao; Tao, Xue-Qin; Lu, Gui-Ning

    2013-01-01

    This study described the development of a method based on soxhlet extraction combining high performance liquid chromatography (soxhlet-HPLC) for the accurate detection of BDE-209 in soils. The solvent effect of working standard solutions in HPLC was discussed. Results showed that 1 : 1 of methanol and acetone was the optimal condition which could totally dissolve the BDE-209 in environmental samples and avoid the decrease of the peak area and the peak deformation difference of BDE-209 in HPLC. The preliminary experiment was conducted on the configured grassland (1 μg/g) to validate the method feasibility. The method produced reliable reproducibility, simulated soils (n = 4) RSD 1.0%, and was further verified by the analysis e-waste contaminated soils, RSD range 5.9–11.4%. The contamination level of BDE-209 in burning site was consistent with the previous study of Longtang town but lower than Guiyu town, and higher concentration of BDE-209 in paddy field mainly resulted from the long-standing disassembling area nearby. This accurate and fast method was successfully developed to extract and analyze BDE-209 in soil samples, showing its potential use for replacing GC to determinate BDE-209 in soil samples. PMID:24302876

  17. 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.

  18. High Performance Liquid Metal Battery with Environmentally Friendly Antimony-Tin Positive Electrode.

    Science.gov (United States)

    Li, Haomiao; Wang, Kangli; Cheng, Shijie; Jiang, Kai

    2016-05-25

    For the first time, Sb-Sn alloys are reported as environmentally friendly positive electrodes for high performance liquid metal batteries (LMBs). Meanwhile, the dominant role of Sb in setting the potential and the inert "solvent" role of Sn in lowering the melting point and decreasing the cell cost are clarified on the basis of electrochemical titration and ex situ analysis. The Li||Sb-Sn LMB exhibits superior rate performance (only 13% capacity loss from 100 mA cm(-2) to 1 A cm(-2) of current densities), low materials cost (73 $ kW h(-1)), and high energy density (200.4 W h kg(-1)) at reduced operating temperature. Most notably, after 3500 h of operation (more than 430 full charge-discharge cycles), a discharge capacity of 20.6 Ah is maintained with a capacity retention of 96.7%, corresponding to a fade rate of 0.0078% per cycle, which potentially meets the metrics of large-scale energy storage without environmental concerns.

  19. Quantitative analysis of mitragynine in human urine by high performance liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Lu, Shijun; Tran, Buu N; Nelsen, Jamie L; Aldous, Kenneth M

    2009-08-15

    Mitragynine is the primary active alkaloid extracted from the leaves of Mitragyna speciosa Korth, a plant that originates in South-East Asia and is commonly known as kratom in Thailand. Kratom has been used for many centuries for their medicinal and psychoactive qualities, which are comparable to that of opiate-based drugs. Kratom abuse can lead to a detectable content of mitragynine residue in urine. Ultra trace amount of mitragynine in human urine was determined by a high performance liquid chromatography coupled to an electrospray tandem mass spectrometry (HPLC-ESI/MS/MS). Mitragynine was extracted by methyl t-butyl ether (MTBE) and separated on a HILIC column. The ESI/MS/MS was accomplished using a triple quadrupole mass spectrometer in positive ion detection and multiple reactions monitoring (MRM) mode. Ajmalicine, a mitragynine's structure analog was selected as internal standard (IS) for method development. Quality control (QC) performed at three levels 0.1, 1 and 5 ng/ml of mitragynine in urine gave mean recoveries of 90, 109, and 98% with average relative standard deviation of 22, 12 and 16%, respectively. The regression linearity of mitragynine calibration ranged from 0.01 to 5.0 ng/ml was achieved with correlation coefficient greater than 0.995. A detection limit of 0.02 ng/ml and high precision data within-day and between days analysis were obtained.

  20. Development of high-performance liquid chromatographic for quality and authenticity control of Chinese propolis.

    Science.gov (United States)

    Cui-ping, Zhang; Shuai, Huang; Wen-ting, Wei; Shun, Ping; Xiao-ge, Shen; Ya-jing, Li; Fu-liang, Hu

    2014-07-01

    A RP-high-performance liquid chromatography (HPLC) method was developed for quality control of Chinese propolis by simultaneous analysis of 12 flavonoids and 8 phenolic acids. The results showed that vanillic acid, rutin, myricetin, and luteolin were not detected in all of the analyzed propolis and poplar tree gum samples. The caffeic acid, ferulic acid and p-coumaric acid were not detected in poplar tree gum but were detected in propolis, which suggest that they are practical indexes of distinguishing propolis from poplar tree gum. The flavonoid profiles of poplar tree gum were found to be similar to those of propolis, which are dominated by pinobanksin, pinocembrin, 3-O-acetylpinobanksin, chrysin, and galangin. Therefore, the proposed method could be applied to exclude poplar tree gum from propolis with cafferic acid, ferulic acid, and p-coumaric acid as qualitative markers, and distinguish poplar source resin from other illegal substances, and evaluate the quality grading of poplar-type propolis with pinobanksin, pinocembrin, 3-O-acetylpinobanksin, chrysin, and galangin as qualitative and quantitative markers. © 2014 Institute of Food Technologists®

  1. A validated new method for nevirapine quantitation in human plasma via high-performance liquid chromatography.

    Science.gov (United States)

    Silverthorn, Courtney F; Parsons, Teresa L

    2006-01-01

    A fully validated and clinically relevant assay was developed for the assessment of nevirapine concentrations in neonate blood plasma samples. Solid-phase extraction with an acid-base wash series was used to prepare subject samples for analysis. Samples were separated by high performance liquid chromatography and detected at 280 nm on a C8 reverse-phase column in an isocratic mobile phase. The retention times of nevirapine and its internal standard were 5.0 and 6.9 min, respectively. The method was validated by assessment of accuracy and precision (statistical values 0.996) and the average recovery was 93% (n = 18). The lower limit of quantification (relative standard deviation <20%) was determined to be 25 ng/mL for 50 microL of plasma, allowing detection of as little as 1.25 ng of nevirapine in a sample. This value represents an increase in sensitivity of up to 30-fold over previously published methods. Copyright 2005 John Wiley & Sons, Ltd.

  2. Analysis of Fluconazole in Human Urine Sample by High Performance Liquid Chromatography Method

    Science.gov (United States)

    Hermawan, D.; Ali, N. A. Md; Ibrahim, W. A. Wan; Sanagi, M. M.

    2013-04-01

    A method for determination of fluconazole, antifungal drug in human urine by using reversed-phased high performance liquid chromatography (RP-HPLC) with ultraviolet (UV) detector was developed. Optimization HPLC conditions were carried out by changing the flow rate and composition of mobile phase. The optimum separation conditions at a flow rate 0.85 mL/min with a composition of mobile phase containing methanol:water (70:30, v/v) with UV detection at a wavelength 254 nm was able to analyze fluconazole within 3 min. The excellent linearity was obtained in the range of concentration 1 to 10 μg/mL with r2 = 0.998. The limit of detection (LOD) and limit of quantitation (LOQ) were 0.39 μg/mL and 1.28 μg/mL, respectively. Solid phase extraction (SPE) method using octadecylsilane (C18) as a sorbent was used to clean-up and pre-concentrated of the urine sample prior to HPLC analysis. The average recoveries of fluconazole in spiked urine sample was 72.4% with RSD of 3.21% (n=3).

  3. Determination of isotopically labelled monoesterphthalates in urine by high performance liquid chromatography-mass spectrometry.

    Science.gov (United States)

    Anderson, Warwick A C; Barnes, Karen A; Castle, Laurence; Damant, Andrew P; Scotter, Michael J

    2002-09-01

    A method of analysis for monoesters of phthalic acid ('monoesterphthalates') in human urine has been developed. The method was needed to determine the hydrolysis and excretion efficiency of isotopically-labelled phthalate diesters ('phthalates') when they were fed to volunteers as part of a biomarker study to estimate total exposure to phthalates. The targeted substances were 13C-monobutylphthalate (MBP), 2H4-monobutylphthalate (MBP), 2H4-monobenzylphthalate (MBeP), 13C-monocyclohexylphthalate (MCHP), 13C-monoethylhexylphthalate (MEHP), and 13C-monoisodecylphthalate (MIDP). The monoesters in urine were deconjugated enzymatically, extracted into solvent, and then determined by high performance liquid chromatography-mass spectrometry (LC-MS) using atmospheric pressure chemical ionisation in the negative ion mode. The limits of determination were 10 ng ml(-1) for MBP, MCHP, MBeP and MEHP, and 40 ng ml(-1) for MIDP. The recovery from urine spiked at 100 ng ml(-1) was in the range from 70 to 85% except for MIDP which was lower at 55%. The between-batch reproducibility of the analysis was in the range 8 to 17% (n = 6 batches on separate days).

  4. Detection of HEMA in self-etching adhesive systems with high performance liquid chromatography

    Science.gov (United States)

    Panduric, V.; Tarle, Z.; Hameršak, Z.; Stipetić, I.; Matosevic, D.; Negovetić-Mandić, V.; Prskalo, K.

    2009-04-01

    One of the factors that can decrease hydrolytic stability of self-etching adhesive systems (SEAS) is 2-hydroxymethylmethacrylate (HEMA). Due to hydrolytic instability of acidic methacrylate monomers in SEAS, HEMA can be present even if the manufacturer did not include it in original composition. The aim of the study was to determine the presence of HEMA because of decomposition by hydrolysis of methacrylates during storage, resulting with loss of adhesion strength to hard dental tissues of the tooth crown. Three most commonly used SEAS were tested: AdheSE ONE, G-Bond and iBond under different storage conditions. High performance liquid chromatography analysis was performed on a Nucleosil C 18-100 5 μm (250 × 4.6 mm) column, Knauer K-501 pumps and Wellchrom DAD K-2700 detector at 215 nm. Data were collected and processed by EuroCrom 2000 HPLC software. Calibration curves were made related eluted peak area to known concentrations of HEMA (purchased from Fluka). The elution time for HEMA is 12.25 min at flow rate 1.0 ml/min. Obtained results indicate that no HEMA was present in AdheSE ONE because methacrylates are substituted with methacrylamides that seem to be more stable under acidic aqueous conditions. In all other adhesive systems HEMA was detected.

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

    Science.gov (United States)

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

    2014-10-01

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

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

    Science.gov (United States)

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

    2013-11-01

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

  7. Quantitative Determination of Compounds from Akebia quinata by High-Performance Liquid Chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Yen, Nguyen; Thu, Nguyen; Zhao, Bing Tian; Woo, Mi Hee; Min, Byung Sun [Catholic Univ. of Daegu, Gyeongsan (Korea, Republic of); Lee, Jae Hyun [Dongguk Univ., Yongin (Korea, Republic of); Kim, Jeong Ah [Kyungpook National Univ., Daegu (Korea, Republic of); Son, Jong Keun [Yeungnam Univ., Gyeongsan (Korea, Republic of); Choi, Jae Sui [Pukyung National Univ., Busan (Korea, Republic of); Woo, Eun Rhan [Chosun Univ., Gwangju (Korea, Republic of)

    2014-07-15

    To provide the scientific corroboration of the traditional uses of Akebia quinata (Thunb.) Decne., a detailed analytical examination of A. quinata stems was carried out using a reversed-phase high performance liquid chromatography (RP-HPLC) method coupled to photodiode array detector (PDA) for the simultaneous determination of four phenolic substances; cuneataside D, 2-(3,4-dihydroxyphenyl)ethyl-O-β-D-glucopyranoside, 3-caffeoylquinic acid and calceolarioside B. Particular attention was focused on the main compound, 3-caffeoylquinic acid, which has a range of biological functions. In addition, 2-(3,4-dihydroxyphenyl)ethyl-O-β-D-glucopyranoside was considered as a discernible marker of A. quinata from its easy confuse plants. The contents of compounds 2 and 3 ranged from 0.72 to 2.68 mg/g and from 1.66 to 5.64 mg/g, respectively. The validation data indicated that this HPLC/PDA assay was used successfully to quantify the four phenolic compounds in A. quinata from different locations using relatively simple conditions and procedures. The pattern-recognition analysis data from 53 samples classified them into two groups, allowing discrimination between A. quinata and comparable herbs. The results suggest that the established HPLC/PDA method is suitable for quantitation and pattern-recognition analyses for a quality evaluation of this medicinal herb.

  8. Determination of 5-methylcytosine from plant DNA by high-performance liquid chromatography.

    Science.gov (United States)

    Wagner, I; Capesius, I

    1981-06-26

    The relative amounts of the five nucleosides (deoxycytidine, 5-methyldeoxycytidine, deoxyadenosine, deoxyguanosine and thymidine) in the DNA of nine plant species, one plant satellite DNA, and one animal species were determined by high performance liquid chromatography. The method allows the clean separation of the nucleosides from 10 microgram samples with 15 min. The following values for the proportion of methylated cytosines among all cytosines were obtained: Lobularia maritima 18.5%, Nicotiana tabacum 32.6%, Pisum sativum 23.2%, Rhinanthus minor 29.2%, Sinapsis alba 12.2%, Vicia faba 30.5%, Viscum album 23.2%, Cymbidium pumilum 18.8%, Cymbidium pumilum AT-rich satellite DNA 15.8%, Triticum aestivum 22.4%. DNA of an animal, the gerbil, Meriones unguiculatus, had a methylation percentage of 3.1%. An estimate of the GC content based on the buoyant density of DNA tends to be lower than the actual value, an estimate based on the melting temperature tends to be higher. This supports the finding by other authors that DNA methylation decreases the buoyant density and may increase the melting temperature at high m5C concentration.

  9. 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.

  10. Analysis of serotonin concentrations in human milk by high-performance liquid chromatography with fluorescence detection.

    Science.gov (United States)

    Chiba, Takeshi; Maeda, Tomoji; Tairabune, Tomohiko; Tomita, Takashi; Sanbe, Atsushi; Takeda, Rika; Kikuchi, Akihiko; Kudo, Kenzo

    2017-03-25

    Serotonin (5-hydroxytryptamine, 5-HT) plays an important role in milk volume homeostasis in the mammary gland during lactation; 5-HT in milk may also affect infant development. However, there are few reports on 5-HT concentrations in human breast milk. To address this issue, we developed a simple method based on high-performance liquid chromatography with fluorescence detection (HPLC-FD) for measuring 5-HT concentrations in human breast milk. Breast milk samples were provided by four healthy Japanese women. Calibration curves for 5-HT in each sample were prepared with the standard addition method between 5 and 1000 ng/ml, and all had correlation coefficients >0.999. The recovery of 5-HT was 96.1%-101.0%, with a coefficient of variation of 3.39%-8.62%. The range of 5-HT concentrations estimated from the calibration curves was 11.1-51.1 ng/ml. Thus, the HPLC-FD method described here can effectively extract 5-HT from human breast milk with high reproducibility. Copyright © 2017 Elsevier Inc. All rights reserved.

  11. Simultaneous determination of eleven characteristic lignans in Schisandra chinensis by high-performance liquid chromatography.

    Science.gov (United States)

    Hu, Junyang; Mao, Chunqin; Gong, Xiaodong; Lu, Tulin; Chen, Han; Huang, Zhijun; Cai, Baochang

    2013-04-01

    Schisandra chinensis, one of the well-known traditional Chinese herbal medicines, is derived from the dry ripe fruits of Schisandra chinensis (Turcz.) Baill. according to the 9th China Pharmacopeia. Lignans are the main components isolated from extracts of S. chinensis and their content varies depending on where S. chinensis was collected. We have established a qualitative and quantitative method based on the bioactive lignans for control of the quality of S. chinensis from different sources. To develop a high-performance liquid chromatography method, an Elite ODS C18 column (250 mm Χ 4.6 mm, 5μm) at a column temperature of 30°C and flow rate of 1.0ml/min using acetonitrile (A) and water (B) as the mobile phase with a linear gradient and the peaks were monitored at 217 nm. All calibration curves showed good linearity (r ≥ 0.9995) within test ranges. This method showed good repeatability for the quantification of these eleven components in S. chinensis with intra- and inter-day relative standard deviations less than 0.43% and 1.21%, respectively. In the recovery test, results of accuracy ranged from 99.51% to 101.31% with RSD values less than 2. The validated method can be successfully applied to quantify the eleven investigated components in 22 samples of S. chinensis from different sources.

  12. Methacrylate-bonded covalent-organic framework monolithic columns for high performance liquid chromatography.

    Science.gov (United States)

    Liu, Li-Hua; Yang, Cheng-Xiong; Yan, Xiu-Ping

    2017-01-06

    Covalent-organic frameworks (COFs) are a newfangled class of intriguing microporous materials. Considering their unique properties, COFs should be promising as packing materials for high performance liquid chromatography (HPLC). However, the irregular shape and sub-micrometer size of COFs synthesized via the traditional methods render the main obstacles for the application of COFs in HPLC. Herein, we report the preparation of methacrylate-bonded COF monolithic columns for HPLC to overcome the above obstacles. The prepared COF bonded monolithic columns not only show good homogeneity and permeability, but also give high column efficiency, good resolution and precision for HPLC separation of small molecules including polycyclic aromatic hydrocarbons, phenols, anilines, nonsteroidal anti-inflammatory drugs and benzothiophenes. Compared with the bare polymer monolithic column, the COF bonded monolithic columns show enhanced hydrophobic, π-π and hydrogen bond interactions in reverse phase HPLC. The results reveal the great potential of COF bonded monoliths for HPLC and COFs in separation sciences. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Spectrophotometric and high performance liquid chromatographic methods for sensitive determination of bisphenol A.

    Science.gov (United States)

    Zhuang, Yafeng; Zhou, Meng; Gu, Jia; Li, Xiangmei

    2014-03-25

    A new spectrophotometric method for the determination of trace amounts of bisphenol A based on a diazotization-coupling reaction was developed. In acidic solution, clenbuterol was first diazotized with sodium nitrite, then coupled with bisphenol A to from an azo-compound [I] in NH3-NH4Cl buffer, which shows a maximum absorption at 410 nm. The effects of the amount of sodium nitrite, diazo reaction time, the amount of clenbuterol, coupling reaction time and coupling reaction temperature have been examined. Under the optional conditions, the determination of the linear range of bisphenol A is 0.24-8.4 μg/mL, correlation coefficient is 0.9905 and detection limit of this method is 0.15 μg/mL. The spectrophotometric method is simple, rapid, high sensitivity with better accuracy. High performance liquid chromatography (HPLC) technique combined with this new spectrophotometric method has been also developed for the measurement of bisphenol A. The analysis was achieved on a C18 column using water and methanol as a mobile phase and the detection was done spectrophotometrically at 410 nm. These reported methods were applied to the determination of bisphenol A in hot water in contact with commercially available table-water bottle samples. Copyright © 2013 Elsevier B.V. All rights reserved.

  14. Simultaneous characterization and quantification of 17 main compounds in Rabdosia rubescens by high performance liquid chromatography

    Directory of Open Access Journals (Sweden)

    Sen Guo

    2017-04-01

    Full Text Available Rabdosia rubescens is a healthy herbal tea and well-known Chinese medicinal herb. To evaluate the quality of R. rubescens from China, a high performance liquid chromatography method with dual-wavelength detection was developed and validated. The method was successfully applied for the simultaneous characterization and quantification of 17 main constituents from four different cultivation regions in China. Under optimal conditions, analysis was performed on a Luna C-18 column and gradient elution with a solvent system of acetonitrile and 0.5% (v/v acetic acid–water at a flow rate of 1.0 mL/min and wavelength of 220 nm and 280 nm. All standard calibration curves exhibited good linearity (r2 > 0.9992 within the test ranges. The precision was evaluated by intraday and interday tests, which revealed relative standard deviation values within the ranges of 0.57–2.35% and 0.52–3.40%, respectively. The recoveries were in the range of 96.37–101.66%. The relative standard deviation values for stability and repeatability were < 5%. The contents of some compounds were low and varied with different cultivars. The proposed method could serve as a prerequisite for quality control of R. rubescens materials and products.

  15. Determination of Capsaicin and Dihydrocapsaicin in Capsicum Fruit Samples using High Performance Liquid Chromatography

    Directory of Open Access Journals (Sweden)

    Ayman Abdel Ghafar

    2011-10-01

    Full Text Available The aim of the present study was to determine the content of capsaicin and dihydrocapsaicin in Capsicum samples collected from city markets in Riyadh (Saudi Arabia, calculate their pungency in Scoville heat units (SHU and evaluate the average daily intake of capsaicin for the population of Riyadh. The investigated samples consisted of hot chillies, red chillies, green chillies, green peppers, red peppers and yellow peppers. Extraction of capsaicinoids was done using ethanol as solvent, while high performance liquid chromatography (HPLC was used for separation, identification and quantitation of the components. The limit of detection (LOD of the method was 0.09 and 0.10 µg/g for capsaicin and dihydrocapsaicin, respectively, while the limit of quantification (LOQ was 0.30 and 0.36 µg/g for capsaicin and dihydrocapsaicin, respectively. Hot chillies showed the highest concentration of capsaicin (4249.0 ± 190.3 µg/g and the highest pungency level (67984.60 SHU, whereas green peppers had the lowest detected concentration (1.0 ± 0.9 µg/g; green peppers, red peppers and yellow peppers were non pungent. The mean consumption of peppers for Riyadh city population was determined to be 15.5 g/person/day while the daily capsaicin intake was 7.584 mg/person/day.

  16. A simple high-performance liquid chromatographic practical approach for determination of flurbiprofen

    Directory of Open Access Journals (Sweden)

    Muhammad Akhlaq

    2011-01-01

    Full Text Available A simple, rapid, sensitive, and specific high-performance liquid chromatography (HPLC assay for flurbiprofen has been developed and validated practically. The chromatography was conducted using Gemini C18 column (5 μm; 4.6 mm × 250 mm, Phenomenex, California, USA. The mobile phase containing disodium hydrogen phosphate solution (30 mM pH 7.0 and acetonitrile (50:50; and the isocratic flow rate of 1.0 ml/min were used in the current study. Detection was made at 247 nm. The calibration curve was linear (r ≥ 0.9996 over the concentration range of 5-50 mm/ml. Mean percentage (% recovery ± % relative standard deviation (RSD ranged from 97.07 ± 0.008 to 103.66 ± 0.013. Within-day and between-day precision were also in acceptable range of 98.83 ± 0.004 to 104.56 ± 0.009. In order to confirm the practical applicability of the method developed, flurbiprofen controlled release matrix tablets were subjected to the dissolution studies and the release rate was analyzed. The reported HPLC for flurbiprofen provides several advantages of simplicity, high specificity, accuracy, and very short run-cycle time. It is suggested that the method should be used for the routine quality control analysis of flurbiprofen pure drug and its dosage forms.

  17. Monosodium glutamate in chicken and beef stock cubes using high-performance liquid chromatography.

    Science.gov (United States)

    Demirhan, Buket Er; Demirhan, Burak; Sönmez, Ceren; Torul, Hilal; Tamer, Uğur; Yentür, Gülderen

    2015-01-01

    In this survey monosodium glutamate (MSG) levels in chicken and beef stock cube samples were determined. A total number of 122 stock cube samples (from brands A, B, C, D) were collected from local markets in Ankara, Turkey. High-performance liquid chromatography with diode array detection (HPLC-DAD) was used for quantitative MSG determination. Mean MSG levels (±SE) in samples of A, B, C and D brands were 14.6 ± 0.2 g kg⁻¹, 11.9 ± 0.3 g kg⁻¹, 9.7 ± 0.1 g kg⁻¹ and 7.2 ± 0.1 g kg⁻¹, respectively. Differences between mean levels of brands were significant. Also, mean levels of chicken stock cube samples were lower than in beef stock cubes. Maximum limits for MSG in stock cubes are not specified in the Turkish Food Codex (TFC). Generally the limit for MSG in foods (except some foods) is established as 10 g kg⁻¹ (individually or in combination).

  18. [Determination of sucralose in foods and beverages by ultraviolet derivatization-high performance liquid chromatography].

    Science.gov (United States)

    Chen, Lu-Ying; Liu, Ya-Pan; Ran, Xue-Qin; Sun, Cheng-Jun

    2014-09-01

    To establish a method for determination of sucralose in foods and beverages using high performance liquid chromatography. Sucralose was extracted with water and centrifuged, and then derivatized with benzoyl chloride in alkaline medium. The ultraviolet absorbing derivatives were separated on a Hydro-RP 80 angstroms C18 column (250 mm x 4.6 mm, 4 microm, Synergi) using methanol-water (95:5,V/V) as mobile phase with UV detection at 232 nm. A good correlation (correlation coefficient=0. 999 8) between detected and actual sucralose was achieved in the range of 0.05 to 1.00 microg. The detection limit of sucralose was 0.00125 microg. The recoveries were in the range from 97.4% to 102.0% with relative standard deviations of less than 5.0%. The intraday and interday relative standard deviations of the method were 1.52% and 4.04%, respectively. This method is simple, rapid, and accurate without the need of special detectors, and it can be used for rapid determination of sucralose in foods and beverages.

  19. Simple Quantification of Pentosidine in Human Urine and Plasma by High-Performance Liquid Chromatography

    Directory of Open Access Journals (Sweden)

    Ji Sang Lee

    2017-01-01

    Full Text Available Pentosidine is an advanced glycation end-product (AGE and fluorescent cross-link compound. A simple high-performance liquid chromatographic (HPLC method was developed for the detection and quantification of pentosidine in human urine and plasma. The mobile phase used a gradient system to improve separation of pentosidine from endogenous peaks, and chromatograms were monitored by fluorescent detector set at excitation and emission wavelengths of 328 and 378 nm, respectively. The retention time for pentosidine was 24.3 min and the lower limits of quantification (LLOQ in human urine and plasma were 1 nM. The intraday assay precisions (coefficients of variation were generally low and found to be in the range of 5.19–7.49% and 4.96–8.78% for human urine and plasma, respectively. The corresponding values of the interday assay precisions were 9.45% and 4.27%. Accuracies (relative errors ranged from 87.9% to 115%. Pentosidine was stable in a range of pH solutions, human urine, and plasma. In summary, this HPLC method can be applied in future preclinical and clinical evaluation of pentosidine in the diabetic patients.

  20. A stability-indicating high performance liquid chromatography method to determine apocynin in nanoparticles

    Directory of Open Access Journals (Sweden)

    Juliana Kovalczuk de Oliveira

    2017-04-01

    Full Text Available In this study, we developed and validated a fast, specific, sensitive, precise and stability-indicating high performance liquid chromatography (HPLC method to determine the drug apocynin in bovine serum albumin (BSA nanoparticles. Chromatographic analyses were performed on an RP C18 column and using a photodiode array detector at a wavelength of 276 nm. Mobile phase consisted of a mixture of acetonitrile and 1% acetic acid (60:40, v/v, and it was eluted isocratically at a flow rate of 0.8 mL/min. The retention time of apocynin chromatographic peak was 1.65 min. The method was linear, precise, accurate and specific in the range of 5–100 μg/mL. The intra- and inter-day precisions presented relative standard deviation (RSD values lower than 2%. The method was robust regarding changes in mobile phase proportion, but not for flow rate. Limits of detection and quantitation were 78 ng/mL and 238 ng/mL, respectively. Apocynin was exposed to acid and alkali hydrolysis, oxidation and visible light. The drug suffered mild degradation under acid and oxidation conditions and great degradation under alkali conditions. Light exposure did not degrade the drug. The method was successfully applied to determine the encapsulation efficiency of apocynin in BSA nanoparticles.

  1. [Simultaneous determination of 38 limited colorants in cosmetics by high performance liquid chromatography].

    Science.gov (United States)

    Mao, Xiqin; Li, Chunling; Ren, Guojie; Zhang, Guocui; Li, Xiaofei; Li, Peng

    2015-03-01

    A method has been established for the simultaneous determination of 38 limited colorants in cosmetics by high performance liquid chromatography (HPLC). The samples were extracted by ultrasonic with tetrahydrofuran, methanol, ammonium acetate solution as extraction solvents. After centrifugation, nitrogen blow and redissolved in turn, the extracts were separated on an Agilent zorbax SB-Aq column (150 mm x 3.0 mm, 3.5 µm) using a gradient elution program with acetonitrile and 30 mmol/L ammonium acetate containing 0.075% (v/v) formic acid as mobile phases. The detection wavelengths were set at 254, 416, 484, 514, 590 and 620 nm. The linear ranges of the 38 target compounds were all in the range of 1 to 10 mg/L with correlation coefficients more than 0.999. The limits of quantification (LOQs) for the 38 colorants were in the range of 5-50 µg/g. The average recoveries at two spiked levels ranged from 93.2% to 107.6% with the relative standard deviations (RSDs) less than 10% (n = 6). This method is accurate, simple, sensitive and reliable, and can be used for the analysis of the 38 limited colorants in cosmetics.

  2. Determination of the Thermodegradation of deoxyArbutin in Aqueous Solution by High Performance Liquid Chromatography

    Science.gov (United States)

    Yang, Chao-Hsun; Chen, Yi-Shyan; Lai, Jeng-Shiow; Hong, Willy W. L.; Lin, Chih-Chien

    2010-01-01

    Tyrosinase is the key and rate-limiting enzyme responsible for the conversion of tyrosine into melanin. Competitive inhibition of tyrosinase enzymatic activity results in decreased or absent melanin synthesis by melanocytes in human skin. DeoxyArbutin (4-[(tetrahydro-2H-pyran-2-yl)oxy]phenol), a novel skin whitening agent, was synthesized through the removal of hydroxyl groups from the glucose side-chain of arbutin. DeoxyArbutin not only shows greater inhibition of tyrosinase activity but is also safer than hydroquinone and arbutin. Hence, deoxyArbutin is a potential skin whitening agent for cosmetics and depigmenting drugs; however, stability of this compound under some conditions remains a problem. The lack of stability poses developmental and practical difficulties for the use of deoxyArbutin in cosmetics and medicines. Improving the thermostability of deoxyArbutin is an important issue for its development. In this research, we established an analytical procedure to verify the amount of deoxyArbutin in solutions using a high performance liquid chromatographic (HPLC) method. The results indicate that this novel skin whitening agent is a thermolabile compound in aqueous solutions. Additionally, the rate constant for thermodegradation (k) and the half-life (t1/2) of deoxyArbutin were determined and can be used to understand the thermodegradation kinetics of deoxyArbutin. This information can aid in the application of deoxyArbutin for many future uses. PMID:21152314

  3. Determination of glyphosate in soil/sludge by high performance liquid chromatography.

    Science.gov (United States)

    Sun, Lisi; Kong, Deyang; Gu, Weidong; Guo, Xinyan; Tao, Wenqi; Shan, Zhengjun; Wang, Ying; Wang, Na

    2017-06-16

    In order to evaluate the pollution caused due to glyphosate (Glyp) in soils and sludge, it is important to establish a set of standard determination techniques. In this work, the previously reported HPLC analytical method for determination of Glyp has been improved in order to be applied for all kinds of soils/sludge. The soil/sludge samples were extracted using sodium phosphate and trisodium citrate aqueous solutions. The extract was adjusted to pH 9 and contaminations were removed by washing with n-hexane. The method developed in this work further involves derivatization with 9-fluorenylmethylchloroformate (FMOC-Cl) followed by high performance liquid chromatography (HPLC) coupled with fluorescence detection. The method was validated in three soil (red soil, black soil and paddy soil) and two sludge samples (lake and river sludge) from China and verified in six laboratories. A good linear relationship (correlation coefficients ≥0.999) was observed within the range of 0.005-0.5mg/L. The limit of detection (LOD) and the limit of quantitation (LOQ) were determined to be 0.01mg/kg and 0.04mg/kg, respectively. The precision and accuracy were satisfactory with the relative standard deviation (RSD) lower than 15% and the mean recovery values ranging from 75% to 110% (n=6), that spiked at three levels (0.1, 0.5 and 1.0mg/kg). Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Enantioselective high performance liquid chromatography and supercritical fluid chromatography separation of spirocyclic terpenoid flavor compounds.

    Science.gov (United States)

    Schaffrath, Mathias; Weidmann, Verena; Maison, Wolfgang

    2014-10-10

    Chiral spirocyclic terpenoids are abundant natural flavors with significant impact particularly on the food industry. Chromatographic methods for analytical and preparative separation of these compounds are therefore of high interest to natural product chemists in academia and industry. Gas chromatography on chiral stationary phases is currently the standard method for the separation of volatile terpenoids, limiting the scale to analytical quantities. We report herein high performance liquid chromatography (HPLC) and supercritical fluid chromatography (SFC) protocols for the chiral separation of several racemic spirocyclic terpenoids such as the important flavors theaspirane and vitispirane. A screening of mobile phases and 16 commercially available chiral stationary phases (CSPs) largely based on polysaccharides led to identification of protocols for the separation of all terpenoids tested. SFC methods were found to be particularly useful for the separation of these spirocyclic flavors due to the volatility and low polarity of the compounds. The reported chiral HPLC and SFC protocols are scalable alternatives to gas chromatographic separations of volatile terpenoid flavors. Copyright © 2014 Elsevier B.V. All rights reserved.

  5. Arsenic speciation in soil using high performance liquid chromatography/inductively coupled plasma/mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Bass, D.A.; Yaeger, J.S.; Parish, K.J.; Crain, J.S.; Kiely, J.T.; Gowdy, M.J. [Argonne National Lab., IL (United States); Mohrman, G.B.; Besmer, M.G. [Rocky Mountain Arsenal, Commerce City, CO (United States)

    1996-08-01

    A method has been developed to identify and quantify As(III), As(V), and organoarsenic compounds in soil samples from the Rocky Mountain Arsenal (RMA) by high performance liquid chromatography/inductively coupled plasma/mass spectrometry (HPLC/ICP/MS). The soils were extracted using tetrabutylammonium hydroxide (TBAH) and sonication. The percentages of As(III), As(V), and organoarsenic species extracted from soil samples were 30, 50, and 100 respectively. The arsenic species were not altered during the extraction process. They were separated by reversed-phase, ion-pairing, HPLC using a microbore Inertsil-ODS{trademark} column. The HPLC column effluent was introduced into an ICP/MS system using a direct injection nebulizer (DIN). Detection limits of less than 1 pg were readily obtained for each arsenic species. Internal standards are recommended to increase accuracy and precision. Soil samples spiked with arsenic oxide, sodium arsenate, dimethylarsinic acid (DMAA), and chlorovinyl arsenious acid (CVAA) were extracted, identified and quantified with the HPLC/ICP/MS system. The soil samples were analyzed in support of the analytical needs of a thermal desorption treatability study being conducted at the RMA.

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

    Directory of Open Access Journals (Sweden)

    Mohammad Faraji

    2016-04-01

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

  7. High performance liquid chromatographic determination of oxeladin citrate and oxybutynin hydrochloride and their degradation products.

    Science.gov (United States)

    El-Gindy, Alaa

    2005-08-01

    Two high performance liquid chromatographic (HPLC) methods are presented for the determination of oxeladin citrate (OL) and oxybutynin hydrochloride (OB) and their degradation products. The first method was based on HPLC separation of OL from its degradation product using a Nucleosil C(18) column with a mobile phase consisting of acetonitrile -0.1% phosphoric acid (60:40 v/v). The second method was based on HPLC separation of OB from its degradation product using a VP-ODS C(18) column with a mobile phase consisting of acetonitrile/0.01 M potassium dihydrogen phosphate/diethylamine (60:40:0.2). Quantitation was achieved with UV detection at 220 nm based on peak area. The two HPLC methods were applied for the determination of OL or OB, their degradation products, methylparaben and propylparaben in pharmaceutical preparations. The proposed methods were used to investigate the kinetics of acidic and alkaline degradation processes of OL and OB at different temperatures and the apparent pseudofirst-order rate constant, half-life and activation energy were calculated. The pH-rate profiles of degradation of OL and OB in Britton-Robinson buffer solutions within the pH range 2-12 were studied.

  8. Determination of caffeine, theophylline and theobromine in serum and saliva using high-performance liquid chromatography.

    Science.gov (United States)

    Scott, N R; Chakraborty, J; Marks, V

    1984-03-01

    A method is described for the measurement of theobromine, theophylline and caffeine in serum and saliva by high-performance liquid chromatography (HPLC). A chloroform/isopropanol extract (85:15, v/v) is evaporated to dryness and chromatographed on a 100 X 4.5 mm id Hypersil octadecylsilane column with UV detection at 280 nm. Theobromine, theophylline, caffeine and the internal standard proxyphylline are satisfactorily resolved with an elution system of acetonitrile/tetrahydrofuran/50 mM acetate buffer, pH 4.0, (4:1:95, v/v). No interference is observed from the presence of xanthine metabolites or any of a number of common drugs examined. A good correlation was observed between the concentrations of caffeine in serum and in saliva suggesting that salivary measurements may be useful for the study of caffeine pharmacokinetics in man. Caffeine levels determined by the HPLC procedure described here agreed well with those obtained by a radioimmunoassay method. The method is also suitable for determining the xanthine content of beverages by direct injection of diluted samples.

  9. Geographical tracing of Xihu Longjing tea using high performance liquid chromatography.

    Science.gov (United States)

    Wang, Liyuan; Wei, Kang; Cheng, Hao; He, Wei; Li, Xinghui; Gong, Wuyun

    2014-03-01

    Xihu Longjing tea (XHLJ) is one of the most famous green tea in China. Due to its high price, some inauthentic XHLJ from other tea producing areas appear on the market and hurt the interests of customers and producers. High-performance liquid chromatography (HPLC) combined with the principal component analysis (PCA) and linear discriminant analysis (LDA) methods were applied to the geographical tracing of XHLJ from two other types of Longjing teas and a non-Longjing flatten-shaped tea (non-LJ). The chromatograms of the tea samples from four different regions were highly similar. It was difficult to classify 4 types of teas directly by PCA. However, high total accuracy rates of 94.8% and 87.6% for the training and test set were achieved for distinguishing XHLJ from the other three types of tea by stepwise discriminant analysis. The identification accuracy of XHLJ from non-LJ was the highest, suggesting geographical distance might play an important role in this process. In summary, a combination of chromatographic chemical fingerprints with LDA provides a simple and rapid approach for the identification of XHLJ from other teas. Copyright © 2013 Elsevier Ltd. All rights reserved.

  10. Determination of betamethasone dipropionate and salicylic acid in pharmaceutical preparations by high-performance liquid chromatography.

    Science.gov (United States)

    Kedor-Hackmann, E R; Gianotto, E A; Santoro, M I

    1998-06-01

    The simultaneous determination of betamethasone dipropionate (BD) and salicylic acid (SA) in both ointment and topical solution was developed using high-performance liquid chromatography (HPLC). The method was standardized using a LiChrospher 100 RP-18 (125 x 4 mm, 5 microns) column, acetonitrile-tetrahydrofuran-acetic acid 1% (25:20:55 v/v), apparent pH 3.3, as mobile phase, and UV detection at 254 nm. The peak area response versus concentration was linear in a concentration range from 5.0 to 50.0 micrograms/ml of BD and from 20.0 to 200.0 micrograms/ml of SA. The correlation coefficients were 0.9997 for BD and 0.9987 for SA, and the relative standard errors of estimates were 1.38% for BD and 3.27% for SA. The coefficient of variation and the recovery average were, respectively, 0.41-1.15% and 100.09% for BD, and 0.57-0.95% and 99.79% for SA.

  11. Determination by high-performance liquid chromatography of phenylbutazone in samples of plasma from fighting bulls.

    Science.gov (United States)

    Marti, M I González; Sánchez, González C I; Jiménez, Hernández; Cachán, García; Castro, de Cabo M J; Cuadrado, A L Garzón

    2002-03-25

    The purpose of this study was to investigate the possible presence of phenylbutazone in plasma samples from fighting bulls killed in 2nd and 3rd category bullrings in the province of Salamanca (Spain) in 1998, 1999 and 2000. For quantitative and qualitative determination, a high-performance liquid chromatograph was used, equipped with a photodiode-array detector and setting wavelengths at 240, 254 and 284 nm. The mobile phase optimized for the simultaneous detection of dexamethasone, betamethasone, flunixin and phenylbutazone, was 0.01 M acetic acid pH 3 in methanol (35:65 v/v) at a flow rate of 1 ml/min. Plasma samples were deproteinized with 400 microl of acetonitrile and 20 microl of the supernatant were injected directly into the chromatographic system equipped with a Lichrospher 60 RP select B column and guard column. For the quantitative analysis, standard calibration curves were made in a concentration range between 0.25 and 30 microg/ml, using betamethasone as internal standard. The retention time of phenylbutazone was 8.7 +/- 0.2 min and recovery was 83%. The detection and quantification limits were 0.016 and 0.029, respectively for A=240 nm. The study results show that 17 of the 74 samples analyzed in 1998, 18 of those from 1999 and 10 of those from 2000 were positive for phenylbutazone.

  12. High performance liquid chromatography method for residues analysis of thidiazuron in apple and soil.

    Science.gov (United States)

    Hu, Ji-Ye; Hu, Ya-Qin; Chen, Yang; Yang, Tao

    2011-10-01

    A rapid, sensitive and reliable analytical method for thidiazuron residues in apple and soil was established. The residual levels of the pesticide in apple and soil were determined by high performance liquid chromatography (HPLC) with UV detector. Samples of apple and soil were extracted with acetonitrile-water solutions, and then cleaned up by Florisil or C(18) cartridges. The results showed good linearity (r(2)=1.000) over the concentration range of 0.01-5.0 mg/L. Limits of quantification (LOQ) of the method were 0.01 mg/kg for both soil and apple. Recovery from the apple and soil samples were 83.36%-84.08% and 85.27%-89.83%, respectively, and the corresponding relative standard deviations (RSDs) of the recovery data were 0.155%-0.524% and 0.475%-4.79% for the three fortified levels (0.01, 0.1, 0.5 mg/kg). The analyte in the samples were further confirmed by electrospray ionization tandem mass spectrometry (ESI-MS/MS). It was demonstrated that the proposed method was simple and efficient, and particularly suitable for detecting thidiazuron residues in apple and soil. © Springer Science+Business Media, LLC 2011

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

    Science.gov (United States)

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

    2002-01-01

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

  14. High performance liquid chromatography determination of theobromine and caffeine in cocoa beans gamma irradiated

    Energy Technology Data Exchange (ETDEWEB)

    Soares, Anderson D.B. [Faculdade de Engenharia de Varginha, MG (Brazil); Mansur Neto, Elias [Minas Gerais Univ., Belo Horizonte, MG (Brazil)

    1997-12-01

    Irradiation is a processing technology that has been shown to be a wholesome process by many scientific studies conducted worldwide during the past 40 years, which has been approved by 37 countries. Irradiated foods have been studied so extensively, that the effects on foods are better understood than any other preservation process, including food freezing and dehydration. Cocoa beans has been commercially irradiated in countries such as Ivory Coast and Argentina. The alkaloids theobromine and caffeine are responsible for the mildly stimulating properties and bitter taste of cocoa and chocolate products. Previously fermented dried and nonfumigated cocoa beans were irradiated at doses of 0, 5.0, 10.0 and 20.0 kGy using Co-60 gamma rays. The samples were analysed for determining theobromine and caffeine contents in the cocoa beans by TIMBIE et al. (1978) high performance liquid chromatography (HPLC) method. Boiling water extracts were cooled, centrifuged and injected into the chromatograph. Theobromine and caffeine were quantitated at 273 nm and showed the tendency of decreasing as the dose of radiation increases. Theobromine and caffeine ranged from 42.3 to 37.1 mg/g and from 7.60 to 6.13 mg/g. respectively from 0 to 20.0 kGy. These results were discussed in relation to the possible acceptance of radiosterization of cocoa beans commercially up to the dose of 20.0 kGy. (author). 10 refs., 1 tab.

  15. Simultaneous characterization and quantification of 17 main compounds in Rabdosia rubescens by high performance liquid chromatography.

    Science.gov (United States)

    Guo, Sen; Cui, Xueqin; Jiang, Mi; Bai, Lu; Tian, Xiao; Guo, Tiantian; Liu, Qingchao; Zhang, Li; Ho, Chi-Tang; Bai, Naisheng

    2017-04-01

    Rabdosia rubescens is a healthy herbal tea and well-known Chinese medicinal herb. To evaluate the quality of R. rubescens from China, a high performance liquid chromatography method with dual-wavelength detection was developed and validated. The method was successfully applied for the simultaneous characterization and quantification of 17 main constituents from four different cultivation regions in China. Under optimal conditions, analysis was performed on a Luna C-18 column and gradient elution with a solvent system of acetonitrile and 0.5% (v/v) acetic acid-water at a flow rate of 1.0 mL/min and wavelength of 220 nm and 280 nm. All standard calibration curves exhibited good linearity (r 2  > 0.9992) within the test ranges. The precision was evaluated by intraday and interday tests, which revealed relative standard deviation values within the ranges of 0.57-2.35% and 0.52-3.40%, respectively. The recoveries were in the range of 96.37-101.66%. The relative standard deviation values for stability and repeatability were < 5%. The contents of some compounds were low and varied with different cultivars. The proposed method could serve as a prerequisite for quality control of R. rubescens materials and products. Copyright © 2016. Published by Elsevier B.V.

  16. High-performance liquid chromatographic postcolumn reaction detection based on a competitive binding system

    Energy Technology Data Exchange (ETDEWEB)

    Przyjazny, A.; Kjellstroem, T.L.; Bachas, L.G. (Univ. of Kentucky, Lexington (USA))

    1990-12-01

    Postcolumn reactions are typically employed to improve detection in high-performance liquid chromatography (HPLC) separation techniques. This study proposes the use of competitive binding principles in designing novel postcolumn reaction schemes. The feasibility of this approach was tested by using the HPLC determination of biotin and biocytin as a model system. The effluent from the HPLC column was merged with a reagent stream containing avidin, whose bindings sites were occupied by the dye HABA (2-(4{prime}-hydroxyphenylazo)benzoic acid). HABA was displaced by the analytes from the avidin-HABA complex and the free dye was determined with a UV-vis detector at 345 nm. The procedure was optimized with respect to reactor design, reagent concentrations, and the flow rate of reagent solution. Analytical characteristics of the developed procedure were determined and compared with the direct detection of biotin and biocytin at 220 nm. The postcolumn reaction scheme improved the selectivity and sensitivity of the detection of biotin and biocytin while maintaining similar detection limits.

  17. Quantitative analysis of three chiral pesticide enantiomers by high-performance column liquid chromatography.

    Science.gov (United States)

    Wang, Peng; Liu, Donghui; Gu, Xu; Jiang, Shuren; Zhou, Zhiqiang

    2008-01-01

    Methods for the enantiomeric quantitative determination of 3 chiral pesticides, paclobutrazol, myclobutanil, and uniconazole, and their residues in soil and water are reported. An effective chiral high-performance liquid chromatographic (HPLC)-UV method using an amylose-tris(3,5-dimethylphenylcarbamate; AD) column was developed for resolving the enantiomers and quantitative determination. The enantiomers were identified by a circular dichroism detector. Validation involved complete resolution of each of the 2 enantiomers, plus determination of linearity, precision, and limit of detection (LOD). The pesticide enantiomers were isolated by solvent extraction from soil and C18 solid-phase extraction from water. The 2 enantiomers of the 3 pesticides could be completely separated on the AD column using n-hexane isopropanol mobile phase. The linearity and precision results indicated that the method was reliable for the quantitative analysis of the enantiomers. LODs were 0.025, 0.05, and 0.05 mg/kg for each enantiomer of paclobutrazol, myclobutanil, and uniconazole, respectively. Recovery and precision data showed that the pretreatment procedures were satisfactory for enantiomer extraction and cleanup. This method can be used for optical purity determination of technical material and analysis of environmental residues.

  18. High-performance liquid-chromatographic separation of subcomponents of antimycin-A

    Science.gov (United States)

    Abidi, S.L.

    1988-01-01

    Using a reversed-phase high-performance liquid chromatographic (HPLC) technique, a mixture of antimycins A was separated into eight hitherto unreported subcomponents, Ala, Alb, A2a, A2b, A3a, A3b, A4a, and A4b. Although a base-line resolution of the known four major antimycins Al, A2, A3, and A4 was readily achieved with mobile phases containing acetate buffers, the separation of the new antibiotic subcomponents was highly sensitive to variation in mobile phase conditions. The type and composition of organic modifiers, the nature of buffer salts, and the concentration of added electrolytes had profound effects on capacity factors, separation factors, and peak resolution values. Of the numerous chromatographic systems examined, a mobile phase consisting of methanol-water (70:30) and 0.005 M tetrabutylammonium phosphate at pH 3.0 yielded the most satisfactory results for the separation of the subcomponents. Reversed-phase gradient HPLC separation of the dansylated or methylated antibiotic compounds produced superior chromatographic characteristics and the presence of added electrolytes was not a critical factor for achieving separation. Differences in the chromatographic outcome between homologous and structural isomers were interpretated based on a differential solvophobic interaction rationale. Preparative reversed-phase HPLC under optimal conditions enabled isolation of pure samples of the methylated antimycin subcomponents for use in structural studies.

  19. Sources of Variability in Chlorophyll Analysis by Fluorometry and by High Performance Liquid Chromatography. Chapter 22

    Science.gov (United States)

    VanHeukelem, Laurie; Thomas, Crystal S.; Glibert, Patricia M.

    2001-01-01

    The need for accurate determination of chlorophyll a (chl a) is of interest for numerous reasons. From the need for ground-truth data for remote sensing to pigment detection for laboratory experimentation, it is essential to know the accuracy of the analyses and the factors potentially contributing to variability and error. Numerous methods and instrument techniques are currently employed in the analyses of chl a. These methods range from spectrophotometric quantification, to fluorometric analysis and determination by high performance liquid chromatography. Even within the application of HPLC techniques, methods vary. Here we provide the results of a comparison among methods and provide some guidance for improving the accuracy of these analyses. These results are based on a round-robin conducted among numerous investigators, including several in the Sensor Intercomparison and Merger for Biological and Interdisciplinary Oceanic Studies (SIMBIOS) and HyCODE Programs. Our purpose here is not to present the full results of the laboratory intercalibration; those results will be presented elsewhere. Rather, here we highlight some of the major factors that may contribute to the variability observed. Specifically, we aim to assess the comparability of chl a analyses performed by fluorometry and HPLC, and we identify several factors in the analyses which may contribute disproportionately to this variability.

  20. Resolution of triacylglycerol positional isomers by reversed-phase high-performance liquid chromatography.

    Science.gov (United States)

    Momchilova, Svetlana; Tsuji, Koichiro; Itabashi, Yutaka; Nikolova-Damyanova, Boryana; Kuksis, Arnis

    2004-08-01

    The ability of reversed-phase high-performance liquid chromatography (RP-HPLC) to separate some positionally isomeric disaturated and monounsaturated triacylglycerols (TAGs) as intact species is demonstrated for the first time. Mobile phases of acetonitrile modified with methanol, ethanol, 2-propanol, 1-propanol, 1-butanol, acetone, or dichloromethane were tested for the separation of POP-PPO, PLP-PPL, PEP-PPE, and PDP-PPD (P-palmitic, O-oleic, L-linoleic, E-eicosapentaenoic, D-docosahexaenoic acid residue) on a single RP-HPLC column. The resolution improved with increasing number of double bonds in the acyl residues. While POP and PPO were only partially resolved, PDP and PPD were fully separated with all tested mobile phases, except those containing methanol. Also separated were the four TAGs having the same equivalent carbon number (ECN = 42), PEP, PPE, PDP, and PPD, on a single RP-HPLC column with mobile phase acetonitrile-2-propanol (70:30, v/v) at 0.8 mL/min. In all cases the isomer with the unsaturated acyl residue in either 1- or 3-position was retained more strongly than the respective 2-isomer.

  1. [Application of denaturing high performance liquid chromatography for detection of alpha-hemoglobin-stabilizing protein gene].

    Science.gov (United States)

    Wang, Zhipeng

    2011-04-01

    An assay method for alpha-hemoglobin-stabilizing protein (AHSP) gene was established based on denaturing high performance liquid chromatography (DHPLC). The AHSP gene sequences are divided into six fragments. Because of one or two common single nucleotide polymorphism (SNPs) in the first, second, fourth and sixth fragments, all samples should be analyzed individually when the fragments were detected. The third and fifth fragments were detected by DHPLC technique combined with DNA pooling for no common SNP in the fragments. The six common SNPs in AHSP gene can be genotyped accurately by the established method. After analyzing AHSP gene of 40 samples by DHPLC detection and gene sequencing, it was found that the results of the two methods were completely consistent. After AHSP gene of 365 samples being analyzed by DHPLC, two rare SNPs (11,810 G > A and 12,802 C > T)were found. Two missense mutations (AHSP D29V and AHSP V56G) were also found. AHSP D29V mutation is a novel mutation. AHSP V56G is a rare mutation. It demonstrated that this method is suitable for the detection of alpha-hemoglobin-stabilizing protein gene.

  2. Simple ultraviolet and high-performance liquid chromatography methods for the evaluation of sunscreen efficacy.

    Science.gov (United States)

    Maw, Khin Lay; Caton-Williams, Julianne; Salon, Jozef; Huang, Zhen

    2011-08-01

    To prevent DNA damage caused by the ultraviolet (UV) radiation of sunlight, sunscreens are commonly used to protect human skin. Current analysis of sunscreens' effectiveness is done through complicated procedures, including human exposure. We sought to design a simple system using thymidine-thymidine (TT) dinucleotides to analyze the effectiveness of sunscreens. We can directly analyze sunscreen effectiveness and the formation of TT photolesions simply by using UV spectrophotometry and high-performance liquid chromatography (HPLC). Efficient sunscreen has protective effects against UV irradiation damage. We have developed a simple method using TT dinucleotide, UV, and HPLC for the analysis of sunscreen effectiveness. Our research indicates that the analytical results from UV are consistent with those of HPLC, which is used to monitor the formation of the TT photolesions. Moreover, both UV and HPLC analyses indicate that TT dinucleotides are better protected against UV damage, using the sunscreens with higher UVB sun protection factor (SPF) value, and that sunscreens with higher SPF lead to reduced photolesion formation. Our UV and HPLC analyses confirm the SPF grading of commercial sunscreens. In this experiment, only sunscreens were tested. The experiment, therefore, does not apply to other commercial products, such as cosmetic materials that claim UV protection as a secondary benefit. In conclusion, we have established a simple strategy to analyze the effectiveness of sunscreens and the quality of these potential cancer-preventive products. Copyright © 2010 American Academy of Dermatology, Inc. Published by Mosby, Inc. All rights reserved.

  3. Stability-indicating high-performance liquid chromatographic assay method and photostability of carprofen.

    Science.gov (United States)

    Wu, A B; Chen, C Y; Chu, S D; Tsai, Y C; Chen, F A

    2001-01-01

    A rapid, sensitive, and accurate stability-indicating high-performance liquid chromatographic assay method for determining the degradation of carprofen (CPF) is developed and validated under acidic, basic, or photo-irradiated conditions. The analysis is monitored with a Cosmosil 5C18-AR column using a mobile phase of CH3CN-H2O-AcOH (50:49:1, v/v/v) at 260 nm. The developed method satisfies the system suitability criteria, peak integrity, and resolution among the parent drug and its degradation products. The results indicate that the established assay method shows good selectivity and specificity suitable for stability measurements of CPF. CPF is found to be more sensitive to exposure to light and in acidic conditions, but it is stable in a basic medium. The kinetic study of the photodegradation of CPF follows an apparent first-order reaction in a variety of solvents. The solvent effects on the rates of degradation are in the decreasing order of chloroform > dichloromethane > methanol > ethanol > 2-propanol, which is irrelevant to the dielectric constant epsilon. However, the hydrogen-donating ability of the solvents is essential to the photochemical decomposition of CPF. A plot of log k versus the Kirkwood function exhibits a linear relationship in aqueous ethanolic solutions, which implies that degradation proceeds via an ionic mechanism.

  4. Molecular monitoring of the intestinal flora by denaturing high performance liquid chromatography.

    Science.gov (United States)

    Goldenberg, Oliver; Herrmann, Stefanie; Marjoram, Gina; Noyer-Weidner, Mario; Hong, George; Bereswill, Stefan; Göbel, Ulf B

    2007-01-01

    Gut flora analysis is hampered by the complexity of the intestinal microbiota and by inherent limitations of culture-based approaches. Therefore, culture-independent molecular methods based upon 16S rRNA gene analysis were applied successfully for the analysis of complex microbial communities. However, generally accepted and validated profiling methods such as denaturing and temperature gradient gel electrophoresis (DGGE/TGGE) are still laborious and time consuming. Thus, we adapted the separation of amplified bacterial 16S rRNA gene fragments by denaturing high performance liquid chromatography (DHPLC) using the WAVE Microbial Analysis System as a rapid and convenient means to display complex intestinal bacterial communities and to monitor changes in the gut flora. The separation of 16S rRNA gene fragments amplified from reference strains representing main gut bacterial populations and from human stool samples revealed that DHPLC analysis effectively detects bacterial groups predominant in the human gut flora. The investigation of faecal samples from hospitalized patients before, during and after antibiotic therapy showed that PCR-based DHPLC can be used to monitor gut flora changes. Results from DHPLC analysis were comparable with DGGE profiles generated from the same samples, demonstrating that the adapted DHPLC protocol is well suited for the analysis of complex microbial communities.

  5. Enantioselective determination of sotalol enantiomers in biological fluids using high-performance liquid chromatography.

    Science.gov (United States)

    Shimizu, T; Hiraoka, M; Nakanomyo, H

    1995-12-01

    A simple and sensitive high-performance liquid chromatographic (HPLC) method for the determination of (+)-(S)-sotalol and (-)-(R)-sotalol in biological fluids was established. Following extraction with isopropyl alcohol from biological samples on a Sep-Pak C18 cartridge, the eluent was derivatized with 2,3,4,6-tetra-O-acetyl-beta-D-glucopyranosyl isothiocyanate (GITC). The diastereoisomeric derivates were resolved by HPLC with UV detection at 225 nm. Calibration was linear from 0.022 to 4.41 micrograms/ml in human plasma and from 0.22 to 88.2 micrograms/ml in human urine for both (+)-(S)- and (-)-(R)-sotalol. The lower limit of determination was 0.022 microgram/ml for plasma and 0.22 microgram/ml for urine. The within-day and day-to-day coefficients of variation were less than 7.5% for each enantiomer at 0.09 and 1.8 microgram/ml in plasma and at 0.44 and 4.4 micrograms/ml in urine. The method is also applicable to other biological specimens such as rat, mouse and rabbit plasma.

  6. High-performance liquid chromatography/high-resolution mass spectrometry for the characterization of transformation products of ionic liquids.

    Science.gov (United States)

    Fabbri, Debora; Calza, Paola; Noè, Giorgio; Santoro, Valentina; Medana, Claudio

    2017-12-15

    Ionic liquids (ILs) are a subject of active research in the field of alternative solvents. We studied the behaviour of a piperidine IL, 1-butyl-1-methylpiperidinium tetrafluoroborate (BMPA), through the elucidation of its transformation products (TPs) in water. The transformation pathways of BMPA were investigated using high-performance liquid chromatography (HPLC) combined with a hybrid LTQ-Orbitrap instrument on the basis of mass defect filtering. TPs of BMPA were identified by fragmentation patterns and accurate mass measurements. The separation and identification of 32 TPs was achieved. BMPA can be oxidized at different positions in the alkyl chains. The ultimate products corresponds to N-methyl-piperidinium and some byproducts involving ring-opening. Tests of acute toxicity, evaluated with Vibrio Fischeri bacteria, show that BMPA transformation proceeds through the formation of slightly harmful compounds. Results showed that the main transformation pathways of BMPA were alkyl chain hydroxylation/shortening and de-alkylation, and that HPLC/LTQ-Orbitrap can serve as an important analytical platform to gather the unknown TPs of ILs. Copyright © 2017 John Wiley & Sons, Ltd.

  7. Rapid determination of phthalate esters in alcoholic beverages by conventional ionic liquid dispersive liquid-liquid microextraction coupled with high performance liquid chromatography.

    Science.gov (United States)

    Fan, Yingying; Liu, Shuhui; Xie, Qilong

    2014-02-01

    A very simple, fast and environmentally friendly sample extraction method was proposed for the analysis of phthalate esters (PAEs, di-isobutyl phthalate (DIBP), dibutylphthalate (DBP), butylbenzylphthalate (BBP) and bis(2-ethylhexyl)phthalate (DEHP)) in alcoholic beverages by using conventional ionic liquid dispersive liquid-liquid microextraction. The samples were extracted by 160 μL 1-octyl-3-methylimidazolium hexafluorophosphate in the presence of appropriate amount of ethanol and 10% (w/v) sodium chloride solution; the enriched analytes in sedimented phases were analyzed by high performance liquid chromatography-diode array detector (HPLC-DAD). Under the optimum conditions, a satisfactory linearity (in the range of 0.02-1 μg mL(-1) for white spirits and 0.01-0.5 μg mL(-1) for red wines with the correlation coefficients (r) varying from 0.9983 to 1), acceptable recovery rates (88.5-103.5% for white spirits and 91.6-104.6% for red wines), good repeatability (RSD ≤ 8.0%) and low detection limits (3.1-4.2 ng mL(-1) for white spirits and 1.5-2.2 ng mL(-1) for red wines) were obtained. The developed method was successfully applied for the determination of the four PAEs in 30 white spirits and 11 red wines collected locally, and the DBP content in 63% (19:30) white spirits exceeded the specific migration limit of 0.3 mg kg(-1) established by international regulation. © 2013 Elsevier B.V. All rights reserved.

  8. Mutation analysis in {beta}{sub 2-}adrenergic receptor gene by denaturing high performance liquid chromatography (DHPLC)

    Energy Technology Data Exchange (ETDEWEB)

    Park, S.B.; Oh, C.H.; Kim, J.W.; Jang, W.C. [Dankook University, Cheonan (Korea)

    2002-06-01

    We analysed mutation of {beta}{sub 2-}adrenergic receptor gene that controls bronchial asthma by denaturing high performance liquid chromatography (DHPLC) according to ion-pair reversed-phase high performance liquid chromatography (IP-RP-HPLC). We extracted genomic DNA from 50 asthma patients, amplified DNA using PCR, and analysed PCR product by DHPLC. As a result, we obtained that mutation frequency was 15(30%) among 50 cases. Consequently DHPLC mutation detection was confirmed that the result of direct sequencing was coincide exactly. (author). 13 refs., 4 figs.

  9. High-performance liquid chromatography of water-soluble choline metabolites.

    Science.gov (United States)

    Liscovitch, M; Freese, A; Blusztajn, J K; Wurtman, R J

    1985-11-15

    We have developed a new method for the separation of [3H]choline metabolites by high-performance liquid chromatography. Using this method it is possible to separate, in one step, all of the known major water-soluble choline metabolites present in crude acid extracts of cells that have been incubated with [3H]choline, with baseline or near-baseline resolution. We use a gradient HPLC system with a normal-phase silica column as the stationary phase, and a linear gradient of increasing polarity and ionic strength as the mobile phase. The mobile phase is composed of two buffers: Buffer A, containing acetonitrile/water/ethyl alcohol/acetic acid/0.83 M sodium acetate (800/127/68/2/3), and buffer B (400/400/68/53/79), pH 3.6. A linear gradient from 0 to 100% buffer B, with a slope of 5%/min, is started 15 min after injection. At a flow rate of 2.7 ml/min and column temperature of 45 degrees C, typical retention times for the following compounds are (in min): betaine, 10; acetylcholine, 18; choline, 22; glycerophosphocholine, 26; CDP-choline, 31; and phosphorylcholine, 40. This procedure has been applied in tracer studies of choline metabolism utilizing the neuronal NG108-15 cell line and rat hippocampal slices as model systems. While the compounds labeled in the NG108-15 cells were primarily phosphorylcholine and glycerophosphocholine, reflecting high rates of phospholipid turnover, in the hippocampal slices choline and acetylcholine were the major labeled species. Identification of individual peaks was confirmed by comparing the elution profiles of untreated cell extracts with extracts that had been treated with hydrolyzing enzymes of differing specificities. This HPLC method may be useful in studies of acetylcholine and phosphatidylcholine metabolism, and of the possible interrelationships of these compounds in cholinergic cells.

  10. High-performance liquid chromatographic determination of levodropropizine in human plasma with fluorometric detection.

    Science.gov (United States)

    Tagliaro, F; Moffa, M; De Battisti, Z; Smith, F P; Gentile, M

    1996-10-11

    The present paper describes a new high-performance liquid chromatographic method with fluorescence detection for the analysis of levodropropizine [S-(-)-3-(4-phenylpiperazin-1-yl)-propane-1,2-diol] (Levotuss), an anti-tussive drug, in human serum and plasma. A reversed-phase separation of levodropropizine was coupled with detection of the native fluorescence of the molecule, using excitation and emission wavelengths of 240 nm and 350 nm respectively. The analytical column was packed with spherical 5 microns poly(styrene-divinylbenzene) particles and the mobile phase was 0.1 M NaH2PO4 pH 3-methanol (70:30, v/v), containing 0.5% (v/v) tetrahydrofuran. For quantitation, p-methoxylevodropropizine was used as the internal standard. Samples of 200 microliters of either serum or plasma were mixed with 200 microliters of 0.1 M Na2HPO4 pH 8.9 and extracted with 5 ml of chloroform-2-propanol (9:1, v/v). The dried residue from the organic extract was redissolved with distilled water and directly injected into the chromatograph. The limit of detection for levodropropizine, in biological matrix, was about 1-2 ng/ml, at a signal-to-noise ratio of 3. The linearity was satisfactory over a range of concentrations from 3 to 1000 ng/ml (r2 = 0.99910); within-day precision tested in the range 5-100 ng/ml as well as day-to-day reproducibility proved acceptable, with relative standard deviations better than 1% in most cases. Interferences from as many as 91 therapeutic or illicit drugs were excluded.

  11. Estimation of loxoprofen sodium dihydrate in tablets by reverse phase high performance liquid chromatography

    Directory of Open Access Journals (Sweden)

    R. Nanthakumar

    2016-09-01

    Full Text Available A simple and rapid reverse phase high performance liquid chromatographic (RP-HPLC method has been developed and validated for the estimation of loxoprofen sodium dihydrate (LSD in tablets. An isocratic HPLC analysis was performed on Phenomenex, Luna C18(2 (250 × 4.6 mm, 5μ column. The compound was separated with the mixture of 0.4% orthophosphoric acid and acetonitrile in the ratio of 45:55 (v/v as a mobile phase at a flow rate of 1.0 mL/min. UV detection was performed at 210 nm. Run time per sample was 8 min with the retention time of 4.9 min. The system suitability parameters, such as theoretical plate count, tailing and% RSD between six standard injections were within the limits. The method was validated according to ICH guidelines. The method was validated for specificity, precision, linearity, stability of sample solution, intermediate precision, robustness and accuracy. The stability of the sample solution was checked for 24 h at one hour intervals. The results show that the sample solution is stable for at least 24 h. Calibration plots were linear over the concentration range of 10–90 μg/mL as indicated by the correlation coefficient of 0.9992. The% RSD was 0.115 and 1.288 for system precision and method precision, respectively. The % RSD values for intermediate precision studies were less than 2%. The robustness of the method was evaluated by deliberately altering the chromatographic conditions and the results were adhered with the limits. The high recovery and low relative standard deviation confirm the suitability of the method for the estimation of loxoprofen sodium dihydrate in tablets.

  12. Quantitative determination of triterpenoid glycosides in Fatsia japonica Decne. & Planch. using high performance liquid chromatography.

    Science.gov (United States)

    Ye, Xuewei; Yu, Siran; Lian, Xiao-Yuan; Zhang, Zhizhen

    2014-01-01

    Fatsia japonica Decne. & Planch. is a triterpenoid glycoside-rich herb with anti-inflammatory activity for the treatment of rheumatoid arthritis. A method for quantitative analysis of the complex triterpenoid glycosides in this medicinal plant has not been established so far. In this study, a high performance liquid chromatography (HPLC) method was developed for simultaneous qualification of 11 glycosides in F. japonica. The analysis was performed on an ODS-2 Hypersil column (250mm×4.6mm, 5μm) with a binary gradient mobile phase of water and acetonitrile. The established HPLC method was validated in terms of linearity, sensitivity, stability, precision, accuracy, and recovery. Results showed that this method had good linearity with R(2) at 0.99992-0.99999 in the test range of 0.04-9.00μg/μL. The limit of detection (LOD) and limit of quantification (LOQ) for the standard compounds were 0.013-0.020μg/μL and 0.040-0.060μg/μL. The relative standard deviations (RSDs%) of run variations were 0.83-1.40% for intra-day and 0.84-3.59% for inter-day. The analyzed compounds in the samples were stable for at least 36h, and the spike recoveries of the detected glycosides were 99.67-103.11%. The developed HPLC method was successfully applied for the measurements of the contents of 11 triterpenoid glycoside in different parts of F. japonica. Taken together, the HPLC method newly developed in this study could be used for qualitative and quantitative analysis of the bioactive triterpenoid glycosides in F. japonica and its products. Copyright © 2013 Elsevier B.V. All rights reserved.

  13. Quantification of free formaldehyde in carrageenan and processed Eucheuma seaweed using high-performance liquid chromatography.

    Science.gov (United States)

    Hornshøj, Bettina Høj; Kobbelgaard, Sara; Blakemore, William R; Stapelfeldt, Henrik; Bixler, Harris J; Klinger, Markus

    2015-01-01

    In 2010 the European Commission placed a limit on the amount of free formaldehyde in carrageenan and processed Eucheuma seaweed (PES) of 5 mg kg(-1). Formaldehyde is not used in carrageenan and PES processing and accordingly one would not expect free formaldehyde to be present in carrageenan and PES. However, surprisingly high levels up to 10 mg kg(-1) have been found using the generally accepted AOAC and Hach tests. These findings are, per proposed reaction pathways, likely due to the formation of formaldehyde when sulphated galactose, the backbone of carrageenan, is hydrolysed with the strong acid used in these conventional tests. In order to minimise the risk of false-positives, which may lead to regulatory non-compliance, a new high-performance liquid chromatography (HPLC) method has been developed. Initially, carrageenan or PES is extracted with 2-propanol and subsequently reacted with 2,4-dinitrophenylhydrazine (DNPH) to form the chromophore formaldehyde-DNPH, which is finally quantified by reversed-phase HPLC with ultraviolet light detection at 355 nm. This method has been found to have a limit of detection of 0.05 mg kg(-1) and a limit of quantification of 0.2 mg kg(-1). Recoveries from samples spiked with known quantities of formaldehyde were 95-107%. Using this more specific technique, 20 samples of carrageenan and PES were tested for formaldehyde. Only one sample had a detectable content of formaldehyde (0.40 mg kg(-1)), thus demonstrating that the formaldehyde content of commercial carrageenan and PES products are well below the European Commission maximum limit of 5 mg kg(-1).

  14. Development and validation of reverse phase high performance liquid chromatography for citral analysis from essential oils.

    Science.gov (United States)

    Gaonkar, Roopa; Yallappa, S; Dhananjaya, B L; Hegde, Gurumurthy

    2016-11-15

    Citral is a widely used monoterpene aldehyde in aromatherapy, food and pesticide industries. A new validated reverse phase high performance liquid chromatography (RP - HPLC) procedure for the detection and quantification of cis-trans isomers of citral was developed. The RP-HPLC analysis was carried out using Enable C - 18G column (250×4.6mm, 5μ), with acetonitrile and water (70: 30) mobile phase in isocratic mode at 1mL/min flow. A photodiode array (PDA) detector was set at 233nm for the detection of citral. The method showed linearity, selectivity and accuracy for citral in the range of 3-100μg/mL. In order to compare the new RP-HPLC method with the available methods, one of the commercially available essential oil from Cymbopogon flexuosus was analyzed using new RP-HPLC method and the same was analyzed using GC-MS for the comparison of the method for the detection of citral. The GC-MS analysis was done using mass selective detector (MSD) showed citral content to be of 72.76%; wherein the new method showed to contain that same at 74.98%. To prove the application of the new method, essential oils were extracted from lemongrass, lemon leaves and mosambi peels by steam distillation. The citral content present in the essential and also in the condensate was analyzed. The method was found to be suitable for the analysis of citral in essential oils and water based citral formulations with a very good resolution of its components geranial and neral. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. Determination of polycyclic aromatic hydrocarbons in coal combustion gas using high performance liquid chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Katoh, N. [Ishikawajima Harima Heavy Industry Co Ltd, Tokyo (Japan). Research Institution

    2002-11-01

    The study describes a sampling and analysis procedure for polycyclic aromatic hydrocarbons (PAH) at high temperatures in flue gas. Particulate matter sampling was used in conjunction with gas phase sampling. Particulates were collected on quartz fiber filter heated at the same temperature as flue gas. Vaporous PAHs not retained by the filter were cooled at 55{sup o}C and trapped from the gas phase on Tenax-GC polymer beads of 10 g. The sample volume was about 1 m{sup 3}. Tenax-GC has demonstrated high collection efficiency for benzo(a)pyrene (B(a)P) generated at 375{sup o}C under a stream of nitrogen. PAH were extracted with n-pentane for 4 h by a continuous PAH extractor. It demonstrated 99% extraction efficiency for B(a)P spiked on the adsorbent and it was more effective than Soxhlet extraction. The extracts were concentrated to 1 ml of n-pentane in a Kuderna Danish evaporator. Qualitative and quantitative analysis of the extracts were performed by high performance liquid chromatograph (HPLC) with ultraviolet/fluorescence detection. Eight PAH (3,4,5,6-dibenzocarbazole, phenanthrene, anthracene, fluoranthene, pyrene, 2-methylanthracene, benz(a)anthracene, benzo(a)pyrene) were determined in coal combustion gas on reducing NOx procedures. It was demonstrated that the tendency to reduce NOx levels leads to an increase in the PAH present. Moreover total concentration of four PAH (phenanthrene, fluoranthene, pyrene, benzo(a)pyrene) in this study is satisfactory agreement with those measured in the emissions of coal-fired power stations in the literature.

  16. Determination of aflatoxins in medicinal plants by high-performance liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Siddique, Nadeem A; Mujeeb, Mohd; Ahmad, Sayeed; Panda, Bibhu P; Makhmoor, Mohd

    2013-01-01

    The intention of the proposed work is to study the presence of the aflatoxins B1, B2, G1 and G2 in medicinal plants, namely Mucuna pruriens, Delphinium denudatum and Portulaca oleraceae. The aflatoxins were extracted, purified by immunoaffinity column chromatography and analysed by high-performance liquid chromatography-tandem quadrupole mass spectrometry with electrospray ionisation (HPLC-MS/MS). Fungal count was carried out in PDA media. A good linear relationship was found for AFB1, AFB2, AFG1 and AFG2 at 1-10 ppb (r>0.9995). The analyte accuracy under three different spiking levels was 86.7-108.1 %, with low per cent relative standard deviations in each case. The aflatoxins can be separated within 5 to7 min using an Agilent XDB C18-column. We found that AFB1 and AFB2 were in trace amounts below the detection limit in M. pruriens whilst they were not detected in D. denudatum. P. oleraceae was found to be contaminated with AFB1 and AFB2. AFG1 and AFG2 were not detected in M. pruriens, P. oleraceae and were below the detection limit in D. denudatum. This was consistent with very low numbers of fungal colonies observed after 6 hr of incubation. The analytical method developed is simple, precise, accurate, economical and can be effectively used to determine the aflatoxins in medicinal plants and therefore to control the quality of products. The aflatoxin levels in the plant extracts examined were related to the minimal fungal load in the medicinal plants examined.

  17. [Determination of aflatoxins in cashew by high performance liquid chromatography-tandem mass spectrometry].

    Science.gov (United States)

    Bi, Ruifeng; Fan, Zhixian; Fu, Meng

    2011-12-01

    A method for the determination of four aflatoxins in cashew using high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was developed. The sample was extracted with methanol-water (8: 2, v/v) solution, followed by a cleanup procedure with Florisil column. The target compounds were eluted using 5 mL acetone-water-formic acid (96: 3.5:0.5, v/v/v) solution. The eluate was dried under N2, then dissolved in 1 mL methanol. Four aflatoxins were separated in MG C18 column (100 mm x 3.0 mm, 3 microm) adopting a gradient program within 15 min. A triple quadrupole mass spectrometry equipped with an electrospray ionization source operated in the positive ion mode was used to detect the aflatoxins. The good correlation coefficients (r2 > 0.997) of the four aflatoxins were obtained within their respective linear ranges. The limits of detection (S/N = 3) were between 0.009 microg/kg and 0.04 microg/kg, and the limits of quantification (S/N = 10) were between 0.03 microg/kg and 0.12 microg/kg. The recoveries were in a range of 63.0% -78.5% with the relative standard deviations (RSDs) varied from 2.8% to 9.1%. The validation results meet the requirements of trace assay. Matrix effects were estimated and the signal suppression/enhancement ranged from 88.8% to 99.4%. The results indicate that the developed method is simple, fast, accurate, and can be applied for the determination of fours aflatoxins in cashew.

  18. [Determination of 10 heterocyclic aromatic amines in beef jerky by high performance liquid chromatography].

    Science.gov (United States)

    Wan, Kehui; Peng, Zengqi; Shao, Bin; Yao, Yao; Shi, Jinming

    2012-03-01

    An analytical method was developed for the simultaneous determination of 10 heterocyclic aromatic amines (HAAs) in beef jerky by solid phase extraction-high performance liquid chromatography (SPE-HPLC). The HAAs were eluted from an Extrelut NT 20 SPE column with 60 mL dichlormethane (containing 5% toluene), and then the extract was purified with a propylsulfonic acid silica (PRS) column and a C18 SPE column, and finally, the HAAs were stored in a methanol-ammonia solution. The separation was achieved by using a TSK-gel ODS-80 column and a gradient elution with the mobile phases of acetonitrile and 0.05 mol/L acetic acid-ammonium acetate buffer (pH 3.5). The identification and quantitative analysis of the HAAs fraction were carried out using an HPLC system with ultraviolet-fluorescence detectors. The results showed that the correlation coefficients of the 10 HAAs were all above 0.999 and the limits of detection were in the range from 0.02 to 2.46 ng/g. The recoveries of the 10 HAAs spiked in beef samples were 61.69% - 101.81% with the relative standard deviations (RSDs) between 0.28% and 7.81%. 1-Methyl-9H-pyrido[4,3-b] indole (Harman) and 9H-pyrido [4,3-b]indole (Norharman) were detected in all beef jerky, and the total HAAs content of beef jerky were between 16.65 and 60.38 ng/g. This method is with wide linear range and high sensitivity, and is enough for the analysis of the HAAs in actual meat samples.

  19. Enantiomeric Separations of Pyriproxyfen and its Six Chiral Metabolites by High-Performance Liquid Chromatography.

    Science.gov (United States)

    Zhang, Chuntao; Liu, Hui; Liu, Donghui; Wang, Liying; Gao, Jing; Zhou, Zhiqiang; Wang, Peng

    2016-03-01

    Pyriproxyfen is a chiral insecticide, and over 10 metabolites have been identified in the environment. In this work the separations of the enantiomers of pyriproxyfen and its six chiral metabolites were studied by high-performance liquid chromatography (HPLC). Both normal phase and reverse phase were applied using the chiral columns Chiralpak IA, Chiralpak IB, Chiralpak IC, Chiralcel OD, Chiralcel OD-RH, Chiralpak AY-H, Chiralpak AD-H, Chiracel OJ-H, (R,R)-Whelk-O 1, and Lux Cellulose-3. The effects of the chromatographic parameters such as mobile phase composition and temperature on the separations were investigated and the enantiomers were identified with an optical rotation detector. The enantiomers of these targets could obtain complete separations (resolution factor Rs > 1.5) on Chiralpak IA, Chiralpak IB, Chiralcel OD, Chiralpak AY-H, or Chiracel OJ-H under normal conditions. Chiralcel OJ-H showed the best chiral separation results with n-hexane as mobile phase and isopropanol (IPA) as modifier. The simultaneous enantiomeric separation of pyriproxyfen and four chiral metabolites was achieved on Chiralcel OJ-H under optimized condition: n-hexane/isopropanol = 80/20, 15°C, flow rate of 0.8 ml/min, and UV detection at 230 nm. The enantiomers of pyriproxyfen and the metabolites , , and obtained complete separations on Chiralpak IA, Chiralpak IC, and Lux Cellulose-3 under reverse phase using acetonitrile/water as the mobile phase. The retention factors (k) and selectivity factors (α) decreased with increasing temperature, and the separations were better under low temperature in most cases. The work is of significance for the investigation of the environmental behaviors of pyriproxyfen on an enantiomeric level. © 2016 Wiley Periodicals, Inc.

  20. High performance liquid chromatographic method for determination of ezetimibe in pharmaceutical formulation tablets

    Directory of Open Access Journals (Sweden)

    Hossein Danafar

    2016-09-01

    Full Text Available Ezetimide belongs to a class of lipid lowering    compounds    that    selectively    inhibits intestinal   absorption   of   cholesterol   and   related phytosterols. The purpose of this study is to establish a reliable and quick method for the assignment of ezetimibe in tablets form by high performance liquid chromatography with ultraviolet detection (HPLC-UV. A rapid  and  sensitive  HPLC  method  has  been developed  for  determination  of  ezetimibe in tablets formulation.  Mobile phase was composed of acetonitrile-ammonium acetate (10 mM, pH 3.0, 75:25 (v/v with a flow rate of 1 ml/min. The eluted peaks were detected by a UV detector was set at wavelength of 240 nm. The method results in excellent separation with good resolution of analyte. Standard curves were linear (r = 0.996 over the wide ezetimibe concentration range of 10-60.0 µg mL-1 with acceptable accuracy and precision. The limits of detection (LOD and quantitation (LOQ of the method were 5 and 10 µg/ml, respectively. The average drug recovery was 95.3% throughout the linear concentration range. Statistical  assessment  of  various  in  vitro  dissolution  parameters  and  assay  results was  also  conducted  to  establish  if  there were  any significant difference among them. The validated HPLC method has been used successfully to study ezetimibe. Due to simplicity, rapidity and accuracy of the method, we believe that the method will be useful for routine quality control analysis.

  1. [Advantages in the use of high performance liquid chromatography technique for screening hemoglobinopathies in Venezuela].

    Science.gov (United States)

    Bravo-Urquiola, Martha; Arends, Anabel; Montilla, Silvia; Velásquez, Dalia; Garcìa, Gloria; Alvarez, Maritza; Guevara, José; Castillo, Omar

    2004-12-01

    The hemoglobinopathies are a very heterogeneous group of congenital hemolytic anemias, which includes hemoglobin (Hb) variants, thalassemia and hereditary persistence of fetal hemoglobin (HPFH). The aim of this study was to determine the frequency of hemoglobinopathies using the High Performance Liquid Chromatography (HPLC-CE) technique with the beta-thalassemia Short Program of Variant* Bio Rad. Four thousand blood samples from anemic patients from the Laboratorio de Investigación de Hemoglobinas Anormales, Hospital Universitario de Caracas were studied. Twenty six percent of the anemia patients had hemoglobinopathies. The Hb S was the most frequent variant found, followed by the Hb C and Hb D. Also we observed the association of beta thalassemia with Hb S and Hb C. The quantification of the Hb A by HPLC-CE allowed us to classify the double heterozygote Hb S-Beta Thalassemia in Hb S-beta+ Tal Type 1, Hb S-beta+ Tal Type 2, Hb S-beta(0) Thalassemia. The double heterozygote patients with Hb C-Beta thalassemia were also classified. The HPLC-CE is a rapid, reproducible and precise technique. The reliability of HbA2 measurement by HPLC for the detection of beta thalassaemia without any false positive or false negative results is of great advantage. HPLC may be an appropriate method for rapid screening in population surveys for beta thalassemia and hemoglobin variants carriers. Due to the high incidence of cases, in our country this is very important for their clinical management and the genetic and anthropological impact of an early and precise diagnosis.

  2. Ultrapreconcentration and determination of organophosphorus pesticides in water by solid-phase extraction combined with dispersive liquid-liquid microextraction and high-performance liquid chromatography.

    Science.gov (United States)

    Chen, Junhua; Zhou, Guangming; Deng, Yongli; Cheng, Hongmei; Shen, Jie; Gao, Yi; Peng, Guilong

    2016-01-01

    Solid-phase extraction coupled with dispersive liquid-liquid microextraction was developed as an ultra-preconcentration method for the determination of four organophosphorus pesticides (isocarbophos, parathion-methyl, triazophos and fenitrothion) in water samples. The analytes considered in this study were rapidly extracted and concentrated from large volumes of aqueous solutions (100 mL) by solid-phase extraction coupled with dispersive liquid-liquid microextraction and then analyzed using high performance liquid chromatography. Experimental variables including type and volume of elution solvent, volume and flow rate of sample solution, salt concentration, type and volume of extraction solvent and sample solution pH were investigated for the solid-phase extraction coupled with dispersive liquid-liquid microextraction with these analytes, and the best results were obtained using methanol as eluent and ethylene chloride as extraction solvent. Under the optimal conditions, an exhaustive extraction for four analytes (recoveries >86.9%) and high enrichment factors were attained. The limits of detection were between 0.021 and 0.15 μg/L. The relative standard deviations for 0.5 μg/L of the pesticides in water were in the range of 1.9-6.8% (n = 5). The proposed strategy offered the advantages of simple operation, high enrichment factor and sensitivity and was successfully applied to the determination of four organophosphorus pesticides in water samples. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Determination of erythromycins in fermentation broth using liquid phase extraction with back extraction combined with high performance liquid chromatography

    Directory of Open Access Journals (Sweden)

    Fahimeh Kamarei

    2014-07-01

    Full Text Available Liquid phase extraction with back extraction (LPE-BE combined with high performance liquid chromatography-diode array detection (HPLC-DAD was applied for the extraction and determination of erythromycin A, B and C in fermentation broths. According to this procedure, the fermentation broth with the adjustment pH at a fixed value of 10 was first mixed with organic solvent (Vbroth/Vorg = 1.0. After shaking, the mixture was separated into two phases by microfuging at 13,000 rpm for 15 min. Then back extraction was performed into the acidic aqueous phase with pH 5.0 (Vorg/Vaq = 1.0. After centrifugation at 3000, the two phases were separated and 50 μL of the acidic aqueous phase was injected into the HPLC. The effects of different variables such as the nature of extraction solvent and the pH of samples and buffer were investigated. At the most appropriate conditions, dynamic linear ranges of 0.5–8, 0.1–0.9 and 0.1–0.9 mg mL−1 and limits of detection of 0.03, 0.003 and 0.002 mg mL−1 were obtained for erythromycin A, B and C, respectively. Relative standard deviations (RSDs of the proposed method were less than 9.5%. The mean recoveries were 99.5%. The proposed method is simple and sensitive with highly clean-up effect and it can be used for monitoring the progress of erythromycin fermentation.

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

    Science.gov (United States)

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

    2011-01-01

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

  5. High-performance liquid chromatography separation of unsaturated organic compounds by a monolithic silica column embedded with silver nanoparticles.

    Science.gov (United States)

    Zhu, Yang; Morisato, Kei; Hasegawa, George; Moitra, Nirmalya; Kiyomura, Tsutomu; Kurata, Hiroki; Kanamori, Kazuyoshi; Nakanishi, Kazuki

    2015-08-01

    The optimization of a porous structure to ensure good separation performances is always a significant issue in high-performance liquid chromatography column design. Recently we reported the homogeneous embedment of Ag nanoparticles in periodic mesoporous silica monolith and the application of such Ag nanoparticles embedded silica monolith for the high-performance liquid chromatography separation of polyaromatic hydrocarbons. However, the separation performance remains to be improved and the retention mechanism as compared with the Ag ion high-performance liquid chromatography technique still needs to be clarified. In this research, Ag nanoparticles were introduced into a macro/mesoporous silica monolith with optimized pore parameters for high-performance liquid chromatography separations. Baseline separation of benzene, naphthalene, anthracene, and pyrene was achieved with the theoretical plate number for analyte naphthalene as 36,000 m(-1). Its separation function was further extended to cis/trans isomers of aromatic compounds where cis/trans stilbenes were chosen as a benchmark. Good separation of cis/trans-stilbene with separation factor as 7 and theoretical plate number as 76,000 m(-1) for cis-stilbene was obtained. The trans isomer, however, is retained more strongly, which contradicts the long- established retention rule of Ag ion chromatography. Such behavior of Ag nanoparticles embedded in a silica column can be attributed to the differences in the molecular geometric configuration of cis/trans stilbenes. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Identification and quantification of cannabinoids in Cannabis sativa L. plants by high performance liquid chromatography-mass spectrometry

    NARCIS (Netherlands)

    Aizpurua-Olaizola, Oier; Omar, Jone; Navarro, Patricia; Olivares, Maitane; Etxebarria, Nestor; Usobiaga, Aresatz

    2014-01-01

    High performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS) has been successfully applied to cannabis plant extracts in order to identify cannabinoid compounds after their quantitative isolation by means of supercritical fluid extraction (SFE). MS conditions were optimized by means

  7. Determination of methyldibromoglutaronitrile in cosmetic products by high-performance liquid chromatography with electrochemical detection. Method validation

    DEFF Research Database (Denmark)

    Rastogi, Suresh Chandra; Zachariae, Claus; Johansen, Jeanne D

    2004-01-01

    An increased frequency of contact allergy to methyldibromoglutaronitrile (MDBGN), a commonly used preservative in cosmetics and other consumer products, has been reported in recent years. A high-performance liquid chromatography (HPLC) method for the determination of MDBGN in cosmetic products ha...

  8. Three-mode factor analysis of data on retention in normal-phase high-performance liquid chromatography

    NARCIS (Netherlands)

    Ligny, C.L. de; Spanjer, M.C.; Houwelingen, J.C. van; Weesie, H.M.

    1984-01-01

    It is shown that the Snyder equation is not quite satisfactory for fitting retention data in normal-phase high-performance liquid chromatography (HPLC) on chemically bonded phases. This equation is a special case of the mathematical—statistical three-mode factor analysis model. This model, in its

  9. Constructing a LabVIEW-Controlled High-Performance Liquid Chromatography (HPLC) System: An Undergraduate Instrumental Methods Exercise

    Science.gov (United States)

    Smith, Eugene T.; Hill, Marc

    2011-01-01

    In this laboratory exercise, students develop a LabVIEW-controlled high-performance liquid chromatography system utilizing a data acquisition device, two pumps, a detector, and fraction collector. The programming experience involves a variety of methods for interface communication, including serial control, analog-to-digital conversion, and…

  10. Preparation and Characterization of a Polymeric Monolithic Column for Use in High-Performance Liquid Chromatography (HPLC)

    Science.gov (United States)

    Bindis, Michael P.; Bretz, Stacey Lowery; Danielson, Neil D.

    2011-01-01

    The high-performance liquid chromatography (HPLC) experiment, most often done in the undergraduate analytical instrumentation laboratory course, generally illustrates reversed-phase chromatography using a commercial C[subscript]18 silica column. To avoid the expense of periodic column replacement and introduce a choice of columns with different…

  11. Simultaneous determination of estrogens and progestogens in honey using high performance liquid chromatography-tandem mass spectrometry

    Science.gov (United States)

    This work describes the development and validation of a method for the simultaneous determination of 13 estrogens and progestogens in honey by high performance liquid chromatography-tandem mass spectrometry. The target compounds were preconcentrated by solid phase extraction. Pretreatment variables ...

  12. Development and validation of high-performance liquid chromatography and high-performance thin-layer chromatography methods for the quantification of khellin in Ammi visnaga seed.

    Science.gov (United States)

    Kamal, Abid; Khan, Washim; Ahmad, Sayeed; Ahmad, F J; Saleem, Kishwar

    2015-01-01

    The present study was used to design simple, accurate and sensitive reversed phase-high-performance liquid chromatography RP-HPLC and high-performance thin-layer chromatography (HPTLC) methods for the development of quantification of khellin present in the seeds of Ammi visnaga. RP-HPLC analysis was performed on a C18 column with methanol: Water (75: 25, v/v) as a mobile phase. The HPTLC method involved densitometric evaluation of khellin after resolving it on silica gel plate using ethyl acetate: Toluene: Formic acid (5.5:4.0:0.5, v/v/v) as a mobile phase. The developed HPLC and HPTLC methods were validated for precision (interday, intraday and intersystem), robustness and accuracy, limit of detection and limit of quantification. The relationship between the concentration of standard solutions and the peak response was linear in both HPLC and HPTLC methods with the concentration range of 10-80 μg/mL in HPLC and 25-1,000 ng/spot in HPTLC for khellin. The % relative standard deviation values for method precision was found to be 0.63-1.97%, 0.62-2.05% in HPLC and HPTLC for khellin respectively. Accuracy of the method was checked by recovery studies conducted at three different concentration levels and the average percentage recovery was found to be 100.53% in HPLC and 100.08% in HPTLC for khellin. The developed HPLC and HPTLC methods for the quantification of khellin were found simple, precise, specific, sensitive and accurate which can be used for routine analysis and quality control of A. visnaga and several formulations containing it as an ingredient.

  13. High-Performance Liquid Chromatographic and High-Performance Thin-Layer Chromatographic Method for the Quantitative Estimation of Dolutegravir Sodium in Bulk Drug and Pharmaceutical Dosage Form.

    Science.gov (United States)

    Bhavar, Girija B; Pekamwar, Sanjay S; Aher, Kiran B; Thorat, Ravindra S; Chaudhari, Sanjay R

    2016-01-01

    Simple, sensitive, precise, and specific high-performance liquid chromategraphic (HPLC) and high-performance thin-layer chromatographic (HPTLC) methods for the determination of dolutegravir sodium in bulk drug and pharmaceutical dosage form were developed and validated. In the HPLC method, analysis of the drug was carried out on the ODS C18 column (150 × 4.6 mm, 5 μm particle size) using a mixture of acetonitrile: water (pH 7.5) in the ratio of 80:20 v/v as the mobile phase at the flow rate 1 mL/min at 260 nm. This method was found to be linear in the concentration range of 5-35 μg/mL. The peak for dolutegravir sodium was observed at 3.0 ± 0.1 minutes. In the HPTLC method, analysis was performed on aluminum-backed plates pre-coated with silica gel G60 F254 using methanol: chloroform: formic acid in the proportion of 8:2:0.5 v/v/v as the mobile phase. This solvent system was found to give compact spots for dolutegravir sodium with the Rf value 0.77 ± 0.01. Densitometric analysis of dolutegravir sodium was carried out in the absorbance mode at 265 nm. Linear regression analysis showed good linearity with respect to peak area in the concentration range of 200-900 ng/spot. The methods were validated for precision, limit of detection (LOD), limit of quantitation (LOQ), accuracy, and specificity. Statistical analysis showed that both of the methods are repeatable and specific for the estimation of the said drug. The methods can be used for routine quality control analysis of dolutegravir sodium.

  14. Low density solvent-based dispersive liquid-liquid microextraction for the determination of synthetic antioxidants in beverages by high-performance liquid chromatography.

    Science.gov (United States)

    Çabuk, Hasan; Köktürk, Mustafa

    2013-01-01

    A simple and efficient method was established for the determination of synthetic antioxidants in beverages by using dispersive liquid-liquid microextraction combined with high-performance liquid chromatography with ultraviolet detection. Butylated hydroxy toluene, butylated hydroxy anisole, and tert-butylhydroquinone were the antioxidants evaluated. Experimental parameters including extraction solvent, dispersive solvent, pH of sample solution, salt concentration, and extraction time were optimized. Under optimal conditions, the extraction recoveries ranged from 53 to 96%. Good linearity was observed by the square of correlation coefficients ranging from 0.9975 to 0.9997. The relative standard deviations ranged from 1.0 to 5.2% for all of the analytes. Limits of detection ranged from 0.85 to 2.73 ng mL(-1). The method was successfully applied for determination of synthetic antioxidants in undiluted beverage samples with satisfactory recoveries.

  15. High-Performance Liquid Chromatographic-Tandem Mass Spectrometric Determination of Itraconazole in Human Plasma for Bioavailability and Bioequivalence Studies

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Young Wook; Nam, Dae Young; Kang, Kyoung Hoon; Ha, Kyung Wook; Han, In Hee; Chang, Byung Kon; Yoon, Mi Kyeong; Lee, Jae Hwi [Chung-Ang University, Seoul (Korea, Republic of)

    2006-02-15

    A highly sensitive high-performance liquid chromatographic-tandem mass spectrometric method (HPLC-MSMS) has been developed to quantify itraconazole in human plasma for the purpose of pharmacokinetic studies. Sample preparation was carried out by liquid-liquid extraction using loratadine as an internal standard. Chromatographic separation used a YMC C{sub 18} column, giving an extremely fast total run time of 3 min. The method was validated and used for the bioequivalence study of itraconazole tablets in healthy male volunteers (n = 31). The lower limit of detection proved to be 0.2 ng /mL for itraconazole.

  16. Validation of high performance liquid chromatography method for determination of meloxicam loaded PEGylated nanocapsules

    Directory of Open Access Journals (Sweden)

    Francine Rodrigues Ianiski

    2015-12-01

    Full Text Available abstract A method to ensure that an analytical method will produce reliable and interpretable information about the sample must first be validated, making sure that the results can be trusted and traced. In this study, we propose to validate an analytical high performance liquid chromatography (HPLC method for the quantitation of meloxicam loaded PEGylated nanocapsules(M-PEGNC. We performed a validation study, evaluated parameters including specificity, linearity, quantification limit, detection limit, accuracy, precision and robustness. PEGylated nanocapsules were prepared by interfacial deposition of preformed polymer, and the particle size, polydispersity index, zeta potential, pH value and encapsulation efficiency were characterized. The proposed HPLC method provides selective, linear results in the range of 1.0-40.0 μg/mL; quantification and detection limits were 1.78 μg/mL and 0.59 μg/mL, respectively; relative standard deviation for repeatability was 1.35% and intermediate precision was 0.41% and 0.61% for analyst 1 and analyst 2, respectively; accuracy between 99.23 and 101.79%; robustness between 97.13 and 98.45% for the quantification of M-PEGNC. Mean particle diameters were 261 ± 13 nm and 249 ± 20 nm, polydispersity index was 0.15 ± 0.07 and 0.17 ± 0.06, pH values were 5.0 ± 0.2 and 5.2 ± 0.1, and zeta-potential values were -37.9 ± 3.2 mV e -31.8 ± 2.8 mV for M-PEGNC and placebo(B-PEGNC, respectively. In conclusion, the proposed analytical method is suitable for the quality control of M-PEGNC. Moreover, suspensions showed monomodal size distributions and low polydispersity index indicating high homogeneity of formulations with narrow size distributions, and appropriate pH and zeta potential. The extraction process was efficient for release of meloxicam from nanostructured systems.

  17. Improved method for the determination of triacylglycerols in olive oils by high performance liquid chromatography

    Directory of Open Access Journals (Sweden)

    Cert, A.

    2003-06-01

    Full Text Available The analysis of triacylglycerols has great importance as quality control and origin determination aid in olive oils analytical methodologies. New improvements in the analysis of triacylglycerols by high-performance liquid chromatography in olive oils are developed in order to increase the separation between LLL/OLLn and OLL/OOLn critical pairs used for detection of seed oils in olive oils. Elution with acetone/acetonitrile (55:45 using gradient temperature and isothermal elution with propionitrile were investigated, in comparison with the European Union official method. The best resolution was achieved using propionitrile at 20 ºC. Although the HPLC profile was similar using propionitrile and acetone/acetonitrile, differences in minor triacylglycerols contributing to each HPLC peak were encountered. The precision of the method was good.El análisis de triacilgliceroles tiene gran importancia como herramienta en el control de calidad y en la determinación del origen de los aceites de oliva. Nuevas mejoras en el análisis de triacilgliceroles en aceite de oliva mediante cromatografía líquida de alta eficacia se han desarrollado para mejorar la separación entre las parejas críticas LLL/OLLn y OLL/OOLn usadas en la detección de aceites de semilla en aceite de oliva. Eluciones con acetona/acetonitrilo (55:45 usando gradiente de temperatura y elución con propionitrilo en condiciones isotérmicas han sido investigadas en comparación con el método oficial de la Unión Europea. La mejor resolución se consiguió usando propionitrilo como eluyente a 20 ºC. Aunque el perfil cromatográfico obtenido usando propionitrilo fue similar al obtenido usando acetona/acetonitrilo, se encontraron diferencias en los triacilgliceroles minoritarios que contribuyen a cada pico cromatográfico. La precisión del método fue buena.

  18. Analysis of some selected catechins and caffeine in green tea by high performance liquid chromatography.

    Science.gov (United States)

    El-Shahawi, M S; Hamza, A; Bahaffi, S O; Al-Sibaai, A A; Abduljabbar, T N

    2012-10-15

    Green tea seems to have a positive impact on health due to the catechins-found as flavanols. Thus, the present study was aimed to develop a low cost reversed phase high performance liquid chromatographic (HPLC) method for simultaneous determination of flavanol contents, namely catechin (C), epicatechin (EC), epigallocatechin (EGC), epicatechin 3-gallate (ECG) and epigallocatechin 3-gallate (EGCG) and caffeine in 29 commercial green tea samples available in a Saudi Arabian local market. A C-18 reversed-phase column, acetonitrile-trifluoroacetic acid as a mobile phase, coupled with UV detector at 205 nm, was successfully used for precise analysis of the tested analytes in boiled water of digested tea leaves. The average values of N (No. of theoretical plates), HETP (height equivalent of theoretical plates) and R(s) (separation factor) (at 10 μg ml(-1) of the catechins EC, EGC, EGCG and ECG) were 2.6×10(3)±1.2×10(3), 1.7×10(-3)±4.7×10(-4) cm and 1.7±5.53×10(-2), respectively. The developed HPLC method demonstrated excellent performance, with low limits of detection (LOD) and quantification (LOQ) of the tested catechins of 0.004-0.05 μg ml(-1) and 0.01-0.17 μg ml(-1), respectively, and recovery percentages of 96-101%. The influence of infusion time (5-30 min) and temperature on the content of the flavanols was investigated by HPLC. After a 5 min infusion of the tea leaves, the average concentrations of caffeine, catechin, EC, EGC, ECG and EGCG were found to be in the ranges 0.086-2.23, 0.113-2.94, 0.58-10.22, 0.19-24.9, 0.22-13.9 and 1.01-43.3 mg g(-1), respectively. The contents of caffeine and catechins followed the sequence: EGCG>EGC>ECG>EC>C>caffeine. The method was applied satisfactorily for the analysis of (+)-catechin, even at trace and ultra trace concentrations of catechins. The method was rapid, accurate, reproducible and ideal for routine analysis. Copyright © 2012 Elsevier Ltd. All rights reserved.

  19. Quantitation of artemether in pharmaceutical raw material and injections by high performance liquid chromatography

    Directory of Open Access Journals (Sweden)

    Isabela da Costa César

    2009-12-01

    Full Text Available The quantitation of artemether in both pharmaceutical raw material and injections was carried out by high performance liquid chromatography (HPLC with ultraviolet detection. A Zorbax C18 column (150 x 4.6 mm; 5 μm, at 30 °C, and a mobile phase composed of acetonitrile and water (70:30, at a flow rate of 1ml/min, were used. The detection wavelength was 216 nm and the injection volume was 20 μL. The method proved to be linear (r²=0.9999, precise (RSD A quantificação de artemeter em matéria-prima farmacêutica e solução injetável foi realizada por cromatografia líquida de alta eficiência (CLAE com detecção na região do ultravioleta. Empregou-se coluna Zorbax C18 (150 x 4.6 mm; 5 μm, mantida a 30 °C, e fase móvel composta por acetonitrila e água (70:30, com fluxo de 1 ml/min. A detecção foi realizada a 216 nm, e o volume de injeção foi 20 μl. O método se mostrou linear (r²=0,9999, preciso (DPR < 2,0% para precisão intra-dia e inter-dias e seletivo em relação a possíveis impurezas e excipientes das amostras. Os limites de detecção e quantificação obtidos foram 8 μg/mL e 25 μg/mL, respectivamente. O teor médio de artemeter obtido na análise da matéria-prima farmacêutica foi 99,26% e na solução injetável, 102,08%. O método otimizado e validado pode ser utilizado com sucesso para análises rotineiras em controle de qualidade.

  20. Determination of nucleosides in Cordyceps sinensis and Ganoderma lucidum by high performance liquid chromatography method

    Directory of Open Access Journals (Sweden)

    Masood Shah Khan

    2015-01-01

    Full Text Available Background: Nucleosides are supportive in the regulation and modulation of various physiological processes in body, they acts as precursors in nucleic acid synthesis, enhance immune response, help in absorption of iron and influence the metabolism of fatty acids. Cordyceps sinensis and Ganoderma lucidum are well-known for its use in traditional medicine of China, Nepal and India. They are rich in nucleosides such as adenine, adenosine, cordycepin, etc. Hence, a simple, economic and accurate high-performance liquid chromatography (HPLC analytical method was proposed for determination of adenine and adenosine for the quality control of plants. Materials and Methods: Chromatographic experiments were conducted on YL9100 HPLC system (South Korea. Reversed-phase chromatography was performed on a C18 column with methanol and dihydrogen phosphate as the mobile phase in isocratic elution method at a flow rate of 1.0 mL/min. Detection was carried out at 254 nm, which gives a sharp peak of adenine and adenosine at a retention time of 6.53 ± 0.02 min and 12.41 ± 0.02, respectively. Results and Discussion: Linear regression analysis data for the calibration plot showed a good linear relationship between response and concentration in the range of 25–200 µg/mL for adenosine and 100–800 µg/mL for adenine with regression coefficient of 0.999 and 0.996, respectively. The adenine was found 0.16% and 0.71% w/w in G. lucidum and in C. sinensis, respectively, and adenosine was found to be 0.14% w/w in G. lucidum whereas absent in C. sinensis. Conclusion: The developed HPLC method for the quantification of adenosine and adenine can be used for the quality control and standardization of crude drug and for the different herbal formulations, in which adenine and adenosine are present as major constituents. The wide linearity range, sensitivity, accuracy, and simple mobile phase imply the method is suitable for routine quantification of adenosine and adenine with

  1. Analysis of the Constituents in “Zhu She Yong Xue Shuan Tong” by Ultra High Performance Liquid Chromatography with Quadrupole Time-of-Flight Mass Spectrometry Combined with Preparative High Performance Liquid Chromatography

    Directory of Open Access Journals (Sweden)

    Lin-Lin Wang

    2015-11-01

    Full Text Available “Zhu She Yong Xue Shuan Tong” lyophilized powder (ZSYXST, consists of a series of saponins extracted from Panax notoginseng, which has been widely used in China for the treatment of strokes. In this study, an ultra-high performance liquid chromatography with quadrupole time-of-flight mass spectrometry (UHPLC-Q-TOF/MS combined with preparative high performance liquid chromatography (PHPLC method was developed to rapidly identify both major and minor saponins in ZSYXST. Some high content components were removed through PHPLC in order to increase the sensitivity of the trace saponins. Then, specific characteristic fragment ions in both positive and negative mode were utilized to determine the types of aglycone, saccharide, as well as the saccharide chain linkages. As a result, 94 saponins, including 20 pairs of isomers and ten new compounds, which could represent higher than 98% components in ZSYXST, were identified or tentatively identified in commercial ZSYXST samples.

  2. Comprehensive separation and identification of chemical constituents from Apocynum venetum leaves by high-performance counter-current chromatography and high performance liquid chromatography coupled with mass spectrometry.

    Science.gov (United States)

    Zhang, Yuchi; Liu, Chunming; Zhang, Zhengkun; Wang, Jing; Wu, Guimei; Li, Sainan

    2010-11-15

    High-performance counter-current chromatography (HPCCC) and high performance liquid chromatography coupled with mass spectrometry (HPLC-MS) was efficiently utilized for the separation and identification of the chemical components with a wide range of polarity from the mixed extract of Chinese medicinal herb Apocynum venetum. For HPCCC separation, four sets of solvent systems, n-hexane-ethyl acetate-acetonitrile-water (1.5:3.5:2:4.5, v:v:v:v), ethyl acetate-methanol-water (5:2:5, v:v:v) and n-butanol-methanol-water (5:1:5, v:v:v) were used for the one-step separation by four stages. The HPCCC separation was initiated by filling the column with the lower phase of n-hexane-ethyl acetate-acetonitrile-water (1.5:3.5:2:5, v:v:v:v) as a stationary phase followed by elution with the upper phase of n-hexane-ethyl acetate-acetonitrile-water (1.5:3.5:2:5, v:v:v:v) to separate the hydrophobic compounds (tail to head). Then the mobile phase was switched to the upper phase of ethyl acetate-acetonitrile-water (5:3:7, v:v:v) to eluted the moderate hydrophobic compounds, then the mobile phase was switched to the upper phase of ethyl acetate-methanol-water (5:2:5, v:v:v) to eluted the moderate hydrophilic compounds, and finally the hydrophilic compounds still retained in the column was eluted by the upper phase of n-butanol-methanol-water (5:1:5, v:v:v). A total of 16 named compounds including adhyperforin, hyperforin, amentoflavone, biapigenin, quercetin, avicularin, acetylated isoquercetin, acetylated hyperoside, astragalin, trifolin, isoquercetin, hyperoside, querciturone, rutin, chlorogenic acid and quercetin-3-O-β-D-glucosyl-β-D-glucopyranoside were successfully separated via the four sets of solvent systems in one step operation for 130 min. The compounds separated by HPCCC were identified by comparing with mixed standards data of HPLC-MS as well as NMR data. Crown Copyright © 2010. Published by Elsevier B.V. All rights reserved.

  3. Quantification of LSD in illicit samples by high performance liquid chromatography

    Directory of Open Access Journals (Sweden)

    Pablo Alves Marinho

    2010-12-01

    Full Text Available In the present study, a method using high performance liquid chromatography to quantify LSD, in blotter papers seized in Minas Gerais, was optimized and validated. Linearity, precision, recovery, limits of detection and quantification, and selectivity were the parameters used to evaluate performance. The samples were extracted with methanol:water (1: 1 in an ultra-sound bath. The linearity between 0.05 and 20.00 μg/mL (0.5 and 200.0μg of LSD/blotter was observed with satisfactory mean intra and inter assay precision (RSDr = 4.4% and RSD R = 6.4%, respectively and with mean recoveries of 83.4% and 84.9% to the levels of 1.00 and 20.00 μg/mL (10 and 200μg LSD/blotter. The limits of detection and quantification were 0.01 and 0.05 μg/mL, respectively (0.1 and 0.5 μg of LSD/blotter. The samples of blotters (n =22 were analyzed and the mean value of 67.55 μg of LSD/blotter (RSD=27.5% was found. Thus, the method used showed satisfactory analytical performance, and proved suitable as an analytical tool for LSD determination in illicit samples seized by police forces.No presente trabalho, um método utilizando cromatografia líquida de alta eficiência foi otimizado e validado para quantificar o LSD em selos apreendidos em Minas Gerais. A linearidade, precisão, recuperação, limites de detecção e quantificação e seletividade foram os parâmetros de desempenho avaliados. As amostras foram extraídas com metanol: água (1:1 em banho de ultra-som. A linearidade entre 0,05 a 20,00 mg/mL (0,5 a 200 μg LSD/blotter foi observada com precisão média, intra e inter ensaio, satisfatória (RSDr = 4,4% e RSD R = 6,4%, respectivamente e com recuperações médias de 83,4% e 84,9% para os níveis de LSD de 1,00 e 20,00 mg/mL (10 e 200 μg LSD/selo. Os limites de detecção e quantificação encontrados foram de 0,01 e 0,05 mg/mL, respectivamente (0,1 e 0,5 μg LSD/selo. As amostras de selos (n = 22 foram analisadas e o valor médio encontrado foi de 67

  4. Determination of Beta-Lactam residues in milk by high performance liquid chromatography

    Directory of Open Access Journals (Sweden)

    Roseane Brandão de Brito

    2006-01-01

    Full Text Available A high performance liquid chromatographic method to assay beta-lactam residues in milk was developed and validated. Milk samples were spiked with standard solutions and deproteinated. The extract was cleaned-up on C18 SPE cartridge, the antibiotics eluted with acetonitrile:water (50:50 v/v and derivatized with acetic anhydride and 1-methyl-imidazole solution containing HgCl2. The chromatographic analysis was performed on C18 column using mobile phase consisting of acetonitrile and phosphate buffer (pH 6.5 in the presence of Na2S2O3 gradient and detection at 325 nm. The method was selective for ampicillin, penicillin G and penicillin V, the latter used as internal standard. Average recoveries for ampicillin and penicillin G ranged, respectively, from 60.0% to 104.9% and from 82.7% to 109.2%, with coefficients of variation from 11.1% to 24.6%, and from 2.1% to 25.2%, indicating accuracy and precision. Detection limit of 4.0 µg/L for ampicillin and 3.0 µg/L for penicillin G, and quantification limits of 4.0 µg/L for both were estimated.Um método para determinar resíduos de antibióticos beta-lactâmicos em leite por cromatografia líquida de alta eficiência (CLAE foi desenvolvido e validado. Amostras brancas foram adicionadas de padrão e desproteinizadas. O extrato foi purificado por extração em fase sólida C18, os antibióticos eluídos com acetonitrila:água (50:50 v/v e posteriormente derivatizados com anidrido acético e solução de 1-metil-imidazol contendo HgCl2. A análise cromatográfica foi realizada utilizando coluna C18, fase móvel composta por acetonitrila e tampão fosfato pH 6,5, na presença de Na2S2O3 em gradiente e detecção a 325 nm. O método foi seletivo para ampicilina, penicilina G e penicilina V, sendo este último utilizado como padrão interno. As médias de recuperação para ampicilina e penicilina G situaram-se, respectivamente, na faixa de 60,0% a 104,9% e de 82,7% a 109,2%, com coeficientes de varia

  5. Recent advances in ultra-high performance liquid chromatography for the analysis of traditional chinese medicine

    Science.gov (United States)

    Traditional Chinese medicines (TCMs) have been widely used for the prevention and treatment of various diseases for thousands of years in China. Ultra Performance Liquid Chromatography (UHPLC) is a relatively new technique offering new possibilities in liquid chromatography. This paper reviews recen...

  6. High-performance liquid chromatography of HIV protease inhibitors in human biological matrices

    NARCIS (Netherlands)

    Aarnoutse, Rob E.; verweij-van wissen, CP; Underberg, W.J M; Kleinnijenhuis, Johanneke; Hekster, Yechiel A; Burger, D. M.

    2001-01-01

    Methods for HPLC analysis of protease inhibitors (PIs) in human biological matrices were reviewed. Assays have been developed for analysis of single PIs or for simultaneous measurement of multiple PIs in plasma-serum, saliva, cerebrospinal fluid and semen. Liquid-liquid extraction was most often

  7. High-performance liquid chromatography of HIV protease inhibitors in human biological matrices.

    NARCIS (Netherlands)

    Aarnoutse, R.E.; Verwey-van Wissen, C.P.W.G.M.; Underberg, W.J.M.; Kleinnijenhuis, J.; Hekster, Y.A.; Burger, D.M.

    2001-01-01

    Methods for HPLC analysis of protease inhibitors (PIs) in human biological matrices were reviewed. Assays have been developed for analysis of single PIs or for simultaneous measurement of multiple PIs in plasma-serum, saliva, cerebrospinal fluid and semen. Liquid-liquid extraction was most often

  8. High Performance Liquid Crystalline Polymers from 2,5- furandicarboxylic acid; : Synthesis, Characterization and Properties

    NARCIS (Netherlands)

    Wilsens, Karel

    2017-01-01

    Thermotropic polyesters are an important class of materials for high performance applications.Their low melt viscosities, low thermal expansion coefficients, high use temperatures, and ease in processing allow for the production of high strength and high modulus fibers, films, or compressionmolded

  9. Quantification of urinary uric acid in the presence of thymol and thimerosal by high-performance liquid chromatography

    Science.gov (United States)

    Chen, Y.; Pietrzyk, R. A.; Whitson, P. A.

    1997-01-01

    A high-performance liquid chromatographic method was developed as an alternative to automated enzymatic analysis of uric acid in human urine preserved with thymol and/or thimerosal. Uric acid (tR = 10 min) and creatinine (tR = 5 min) were separated and quantified during isocratic elution (0.025 M acetate buffer, pH 4.5) from a mu Bondapak C18 column. The uric-acid peak was identified chemically by incubating urine samples with uricase. The thymol/thimerosal peak appeared at 31 min during the washing step and did not interfere with the analysis. We validated the high-performance liquid chromatographic method for linearity, precision and accuracy, and the results were found to be excellent.

  10. Advanced Materials and Manufacturing for Low-Cost, High-Performance Liquid Rocket Combustion Chambers Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Silicided niobium alloy (C103) combustion chambers have been used extensively in both NASA and DoD liquid rocket propulsion systems. Niobium alloys offer a good...

  11. Determination of Thiophanate-methyl in Tamoto by High Performance Liquid Chromatography-triple Quadrupole Tandem Mass Spectometry

    OpenAIRE

    XU, WEI-FENG; Han, Kai; SUN Yu-jie; PAN Kang-biao

    2014-01-01

    To evaluate the safety of use of 70% thiophanate-methyl wettable powders in tomato, a supervised trial experiment was conducted to study the residues in tomato. A method of determining thiophanate-methyl by high performance liquid chromatography-tandem mass spectrometry(LC-MSMS)was established. Acetonitrile was used as an extraction solvent, and PSA and anhydrous magnesium were used for sample purifying. Samples were determined and quantified by LC-MSMS in the multiple reaction monitoring mod...

  12. Rapid and accurate simultaneous determination of abamectin and ivermectin in bovine milk by high performance liquid chromatography with fluorescence detection

    OpenAIRE

    Kolberg, D. I. S.; Presta, M.A.; Wickert, C.; Adaime,M. B.; R. Zanella

    2009-01-01

    An analytical method using high performance liquid chromatography with fluorescence detection for the simultaneous determination of abamectin and ivermectin in bovine milk was developed and validated. The best recovery results were achieved by using acetonitrile for extraction of the compounds followed by solid phase extraction in cartridges containing C18 for the purification of the extract. Pre-column derivatization was accomplished with N-methylimidazole and trifluoroacetic anhydride. The ...

  13. Application of microscopy technique and high performance liquid chromatography for quality assessment of Polygonum multiflorum Thunb. (Heshouwu)

    OpenAIRE

    Li Liang; Zhongzhen Zhao; Tingguo Kang

    2014-01-01

    Background: The technique of microscopy has been applied for identification of Chinese materia medica (CMM) since decades. However, very few scientific publications report the combination of conventional microscopy and high performance liquid chromatography (HPLC) techniques for further application to quality assessment of CMM. Objective: The objective of this study is to analyze the quality of the dried root tuber of Polygonum multiflorum Thunb. (Heshouwu) and to establish the relationships ...

  14. Microcytic hypochromic anemia: Should high performance liquid chromatography be used routinely for screening anemic and antenatal patients?

    OpenAIRE

    Joseph Philip; Ravi Shankar Sarkar; Neerja Kushwaha

    2013-01-01

    Background: Hemoglobinopathies are the most common inherited red cell disorders worldwide. Identification of these disorders is immensely important epidemiologically and for improved management protocols. Aim and Objectives: Our aim was to determine the prevalence of hemoglobinopathies in patients with microcytic hypochromic anemia and to assess the suitability of using high performance liquid chromatography (HPLC) routinely for screening antenatal cases and patients with anemia. Materials an...

  15. EPA Method 8321B (SW-846): Solvent-Extractable Nonvolatile Compounds by High Performance Liquid Chromatography-Thermospray-Mass Spectrometry (HPLC-TS-MS) or Ultraviolet (UV) Detection

    Science.gov (United States)

    Method 8321B describes procedures for preparation and analysis of solid, aqueous liquid, drinking water and wipe samples using high performance liquid chromatography and mass spectrometry for extractable non-volatile compounds.

  16. High-performance liquid chromatography of phosphatidylcholine and sphingomyelin with detection in the region of 200 nm.

    Science.gov (United States)

    Jungalwala, F B; Evans, J E; McCluer, R H

    1976-01-01

    A sensitive method for the separation of phosphatidylcholine and sphingomyelin by high-performance liquid chromatographic analysis is described. The elution of the phospholipids from a microparticulate (10 mum) silica-gel chromatographic column was monitored with an ultraviolet spectromonitor at 203 nm. Acetonitrile/methanol/water (65:21:14, by vol.) was used as the solvent. It was shown by using synthetic phosphatidylcholines of knowm fatty acid composition and of varying degree of unsaturation that the absorption at 203 nm was primarily due to the isolated double bonds and the response measured varied with the degree of unsaturation. Approx. 1 nmol of phosphatidylcholine, containing at least one double bond per molecule, can be detected. The amounts of phosphatidylcholine and sphingomyelin could be determined by high-performance liquid chromatography and ultraviolet absorption if the apparent extinction coefficient of the material analyzed was established. Alternatively, peaks were collected and the phospholipids were determined by the analysis of phosphorus. The analysis of phosphatidylcholine and sphingomyelin present in the lipid extracts from animal tissues, blood and amniotic fluids were made without interference from other phospholipids or ultraviolet-absorbing material. The method described here is complementary to the high-performance liquid chromatographic method described previously for the analysis of ethanolamine-containing phosphoglycerides and serine-containing phosphoglycerides [Jungalwala, Turel, Evans and McCluer (1975) Biochem. J. 145, 517-526]. PMID:938476

  17. Synthesis of monodisperse silica microspheres and modification with diazoresin for mixed-mode ultra high performance liquid chromatography separations.

    Science.gov (United States)

    Cong, Hailin; Yu, Bing; Tian, Chao; Zhang, Shuai; Yuan, Hua

    2017-11-01

    Monodisperse silica particles with average diameters of 1.9-2.9 μm were synthesized by a modified Stöber method, in which tetraethyl orthosilicate was continuously supplied to the reaction mixture containing KCl electrolyte, water, ethanol, and ammonia. The obtained silica particles were modified by self-assembly with positively charged photosensitive diazoresin on the surface. After treatment with ultraviolet light, the ionic bonding between silica and diazoresin was converted into covalent bonding through a unique photochemistry reaction of diazoresin. Depending on the chemical structure of diazoresin and mobile phase composition, the diazoresin-modified silica stationary phase showed different separation mechanisms, including reversed phase and hydrophilic interactions. Therefore, a variety of baseline separation of benzene analogues and organic acids was achieved by using the diazoresin-modified silica particles as packing materials in ultra high performance liquid chromatography. According to the π-π interactional difference between carbon rings of fullerenes and benzene rings of diazoresin, C60 and C70 were also well separated by ultra-high performance liquid chromatography. Because it has a small size, the ∼2.5 μm monodisperse diazoresin-modified silica stationary phase shows ultra-high efficiency compared with the commercial C18 -silica high-performance liquid chromatography stationary phase with average diameters of ∼5 μm. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Comparative analysis of steroidal saponins in four Dioscoreae herbs by high performance liquid chromatography coupled with mass spectrometry.

    Science.gov (United States)

    Guo, Long; Zeng, Su-Ling; Zhang, Yu; Li, Ping; Liu, E-Hu

    2016-01-05

    Steroidal saponins, which exhibit multiple pharmacological effects, are the major bioactive constituents in herbal medicines from Dioscoreae species. In this study, a sensitive method based on high performance liquid chromatography-mass spectrometry (HPLC-MS) was established and validated for qualitative and quantitative analysis of steroidal saponins in four Dioscoreae herbs including Dioscoreae Nipponica Rhizome (DNR) and Dioscoreae Hypoglaucae Rhizome (DHR), Dioscoreae Spongiosae Rhizome (DSR) and Dioscoreae Rhizome (DR). A total of eleven steroidal saponins were identified by high performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (HPLC-QTOF/MS). Furthermore, seven major steroidal saponins was simultaneous quantified using a high performance liquid chromatography coupled with triple quadrupole mass spectrometry (HPLC-QQQ/MS). The qualitative and quantitative analysis results indicated that the chemical composition of DNR, DHR and DSR samples exhibited a high level of global similarity, while the ingredients in DR varied greatly from the other three herbs. Moreover, principal component analysis (PCA) and hierarchical clustering analysis (HCA) were performed to compare and discriminate the Dioscoreae herbs based on the quantitative data. The results demonstrated the qualitative and quantitative analysis of steroidal saponins based on HPLC-MS is a feasible method for quality control of Dioscoreae herbs. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. Development and validation of ultra-high performance supercritical fluid chromatography method for determination of illegal dyes and comparison to ultra-high performance liquid chromatography method.

    Science.gov (United States)

    Khalikova, Maria A; Šatínský, Dalibor; Solich, Petr; Nováková, Lucie

    2015-05-18

    A novel simple, fast and efficient ultra-high performance supercritical fluid chromatography (UHPSFC) method was developed and validated for the separation and quantitative determination of eleven illegal dyes in chili-containing spices. The method involved a simple ultrasound-assisted liquid extraction of illegal compounds with tetrahydrofuran. The separation was performed using a supercritical fluid chromatography system and CSH Fluoro-Phenyl stationary phase at 70°C. The mobile phase was carbon dioxide and the mixture of methanol:acetonitrile (1:1, v/v) with 2.5% formic acid as an additive at the flow rate 2.0 mL min(-1). The UV-vis detection was accomplished at 500 nm for seven compounds and at 420 nm for Sudan Orange G, Butter Yellow, Fast Garnet GBC and Methyl Red due to their maximum of absorbance. All eleven compounds were separated in less than 5 min. The method was successfully validated and applied using three commercial samples of chili-containing spices - Chili sauce (Indonesia), Feferony sauce (Slovakia) and Mojo sauce (Spain). The linearity range of proposed method was 0.50-9.09 mg kg(-1) (r ≥ 0.995). The detection limits were determined as signal to noise ratio of 3 and were ranged from 0.15 mg kg(-1) to 0.60 mg kg(-1) (1.80 mg kg(-1) for Fast Garnet) for standard solution and from 0.25 mg kg(-1) to 1.00 mg kg(-1) (2.50 mg kg(-1) for Fast Garnet, 1.50 mg kg(-1) for Sudan Red 7B) for chili-containing samples. The recovery values were in the range of 73.5-107.2% and relative standard deviation ranging from 0.1% to 8.2% for within-day precision and from 0.5% to 8.8% for between-day precision. The method showed potential for being used to monitor forbidden dyes in food constituents. The developed UHPSFC method was compared to the UHPLC-UV method. The orthogonality of Sudan dyes separation by these two methods was demonstrated. Benefits and drawbacks were discussed showing the reliability of both methods for monitoring of studied illegal dyes in real

  20. Intravascular Residence Time Determination for the Cyanide Antidote Dimethyl Trisulfide in Rat by Using Liquid-Liquid Extraction Coupled with High Performance Liquid Chromatography

    Directory of Open Access Journals (Sweden)

    Deepthika De Silva

    2016-01-01

    Full Text Available These studies represent the first report on the intravascular residence time determinations for the cyanide antidote dimethyl trisulfide (DMTS in a rat model by using high performance liquid chromatography coupled with ultraviolet absorption spectroscopy (HPLC-UV. The newly developed sample preparation included liquid-liquid extraction by cyclohexanone. The calibration curves showed a linear response for DMTS concentrations between 0.010 and 0.30 mg/mL with R2 = 0.9994. The limit of detection for DMTS via this extraction method was 0.010 mg/mL, and the limit of quantitation was 0.034 mg/mL. Thus this calibration curve provided a tool for determining DMTS in the range between 0.04 and 0.30 mg/mL. Rats were given 20 mg/kg DMTS dose (in 15% Polysorbate 80 intravenously, and blood samples were taken 15, 60, 90, 120, and 240 min after DMTS injections. The data points were plotted as DMTS concentration in RBCs versus time, and the intravascular residence time was determined graphically. The results indicated a half-life of 36 min in a rat model, suggesting that the circulation time is long enough to provide a reasonable time interval for cyanide antagonism.

  1. Low-density solvent-based dispersive liquid-liquid microextraction followed by high performance liquid chromatography for determination of warfarin in human plasma.

    Science.gov (United States)

    Ghambari, Hoda; Hadjmohammadi, Mohammadreza

    2012-06-15

    Extraction and determination of warfarin, a widely used anticoagulant drug, in human plasma were performed using a new generation of dispersive liquid-liquid microextraction (DLLME) and high performance liquid chromatography (HPLC). The extraction procedure is based on extraction solvents lighter than water and performing of extraction in a specially designed extraction cell. Some important parameters, including kind and volume of extraction and disperser solvents, pH of the sample solution, salt concentration in the sample solution and extraction time were investigated and optimized. Under the optimized conditions (150 μL 1-octanol as extraction solvent, 150 μL methanol as disperser solvent, pH(sample)=2.3, extraction time of 2 min, without salt addition), limit of detection (LOD) of 5 ng mL⁻¹ and extraction recovery of 91.0% were obtained. The calibration curve was linear within the range of 15-3000 ng mL⁻¹ with the square of correlation coefficient (R²) of 0.998. Repeatability and reproducibility of method based on five replicate extraction and determination were 2.8% and 6.5%, respectively. The proposed method was applied successfully for the determination of warfarin in plasma sample from a patient under treatment with this drug, and was demonstrated to be sensitive, efficient, and convenient. Copyright © 2012 Elsevier B.V. All rights reserved.

  2. Vortex-assisted low density solvent based demulsified dispersive liquid-liquid microextraction and high-performance liquid chromatography for the determination of organophosphorus pesticides in water samples.

    Science.gov (United States)

    Seebunrueng, Ketsarin; Santaladchaiyakit, Yanawath; Srijaranai, Supalax

    2014-05-01

    A simple, rapid, effective and eco-friendly preconcentration method, vortex-assisted low density solvent based solvent demulsified dispersive liquid-liquid microextraction (VLDS-SD-DLLME), followed by high performance liquid chromatography-diode array detector (HPLC-DAD) analysis, has been developed for the first time for the determination of four organophosphorus pesticides (OPPs) (e.g., azinphos-methyl, parathion-methyl, fenitrothion and diazinon) in environmental water samples. In this preconcentration procedure, an emulsion was obtained after the mixture of extraction solvent (1-dodecanol) and dispersive solvent (acetonitrile, ACN) was injected rapidly into 10 mL of the sample solution. The vortex agitator aided the dispersion of the extraction solvent into the sample solution. After the formation of an emulsion, the demulsifier (ACN) was added, resulting in the rapid separation of the mixture into two phases without centrifugation. Under optimal conditions, the proposed method provided high extraction efficiency (90-99%), good linearity range (0.5-500 ng mL(-1)), low limits of detection (0.25-1 ng mL(-1)) and good repeatability and recoveries were obtained. Copyright © 2013 Elsevier Ltd. All rights reserved.

  3. Automated dispersive liquid-liquid microextraction coupled to high performance liquid chromatography - cold vapour atomic fluorescence spectroscopy for the determination of mercury species in natural water samples.

    Science.gov (United States)

    Liu, Yao-Min; Zhang, Feng-Ping; Jiao, Bao-Yu; Rao, Jin-Yu; Leng, Geng

    2017-04-14

    An automated, home-constructed, and low cost dispersive liquid-liquid microextraction (DLLME) device that directly coupled to a high performance liquid chromatography (HPLC) - cold vapour atomic fluorescence spectroscopy (CVAFS) system was designed and developed for the determination of trace concentrations of methylmercury (MeHg(+)), ethylmercury (EtHg(+)) and inorganic mercury (Hg(2+)) in natural waters. With a simple, miniaturized and efficient automated DLLME system, nanogram amounts of these mercury species were extracted from natural water samples and injected into a hyphenated HPLC-CVAFS for quantification. The complete analytical procedure, including chelation, extraction, phase separation, collection and injection of the extracts, as well as HPLC-CVAFS quantification, was automated. Key parameters, such as the type and volume of the chelation, extraction and dispersive solvent, aspiration speed, sample pH, salt effect and matrix effect, were thoroughly investigated. Under the optimum conditions, linear range was 10-1200ngL(-1) for EtHg(+) and 5-450ngL(-1) for MeHg(+) and Hg(2+). Limits of detection were 3.0ngL(-1) for EtHg(+) and 1.5ngL(-1) for MeHg(+) and Hg(2+). Reproducibility and recoveries were assessed by spiking three natural water samples with different Hg concentrations, giving recoveries from 88.4-96.1%, and relative standard deviations <5.1%. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Vortex-assisted liquid-liquid micro-extraction and high-performance liquid chromatography for a higher sensitivity methyl methacrylate determination in biological matrices.

    Science.gov (United States)

    Sousa, Tiago F A; Aniceto, Marta C; Amorim, Célia G; Souto-Lopes, Mariana; Pérez-Mongiovi, Daniel; Montenegro, Maria C B S M; Araújo, Alberto N

    2014-05-01

    A vortex-assisted liquid-liquid micro-extraction coupled with high-performance liquid chromatography, with UV-vis, is proposed to pre-concentrate methyl methacrylate and to improve separation in biological matrices. The use of 1-octanol as extracting phase, its volume, the need for a dispersant agent, the agitation conditions and the cooling time before phase separation were evaluated. In optimum conditions, enrichment factors of 20 (±0.5) and enrichment recovery of 99% were obtained. The straightforward association of this extraction process with the HPLC method, previously regulated by the International Organization for Standardization, afforded a detection limit of 122 ng/mL and a quantification limit of 370 ng/mL. The within-batch precision, relative standard deviation, was 3% for a sample with 1.49 µg/mL and 4% for a sample with 13.4 µg/mL. The results showed a between batch-precision of 21% for experiments performed on five different days, for a sample with a concentration of 1.10 µg/mL in methyl methacrylate. Copyright © 2013 John Wiley & Sons, Ltd.

  5. Determination of Fusarium toxins in functional vegetable milks applying salting-out-assisted liquid-liquid extraction combined with ultra-high-performance liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    Hamed, Ahmed M; Arroyo-Manzanares, Natalia; García-Campaña, Ana M; Gámiz-Gracia, Laura

    2017-11-01

    Vegetable milks are considered as functional foods due to their physiological benefits. Although the consumption of these products has significantly increased, they have received little attention in legislation with regard to contaminants. However, they may contain mycotoxins resulting from the use of contaminated raw materials. In this work, ultra-high-performance liquid chromatography tandem mass spectrometry has been proposed for the determination of the most relevant Fusarium toxins (fumonisin B1 and B2, HT-2 and T-2 toxins, zearalenone, deoxynivalenol and fusarenon-X) in different functional beverages based on cereals, legumes and seeds. Sample treatment consisted of a simple salting-out-assisted liquid-liquid extraction with no further clean-up. The method provided limits of quantification between 3.2 and 57.7 µg L-1, recoveries above 80% and precision with RSD lower than 12%. The method was also applied for studying the occurrence of these mycotoxins in market samples of vegetable functional beverages and deoxynivalenol was found in three oat-based commercial drinks.

  6. Preliminary validation of high performance liquid chromatography method for detection of methyl-testosterone residue in carp muscle

    Science.gov (United States)

    Jiang, Jie; Lin, Hong; Fu, Xiaoting; Li, Mingming

    2005-07-01

    The use of synthetic anabolic steroid methyltestosterone (MT) as growth promoter is prohibited in China. Validations of analytical methods for MT residue in food and the results obtained have become indispensable. The high performance liquid chromatography (HPLC) method for the detection of MT with liquid-liquid extraction by trichloromethane-methanol in carp muscle tissue was preliminarily validated with reference to the following parameters: recovery (accuracy) at the 1, 5 and l0 mgkg-1 level, between-run and within-run CV values (repeatability, also called relative standard deviation (RSD)) and limit of detection. The recoveries were above 80% and the between-run and within-run CV values below 10% for muscle tissue. The limit of detection was 0.05 mgkg-1.

  7. A high-performance lab-on-a-chip liquid sensor employing surface acoustic wave resonance

    Science.gov (United States)

    Kustanovich, K.; Yantchev, V.; Kirejev, V.; Jeffries, G. D. M.; Lobovkina, T.; Jesorka, A.

    2017-11-01

    We demonstrate herein a new concept for lab-on-a-chip in-liquid sensing, through integration of surface acoustic wave resonance (SAR) in a one-port configuration with a soft polymer microfluidic delivery system. In this concept, the reflective gratings of a one-port surface acoustic wave (SAW) resonator are employed as mass loading-sensing elements, while the SAW transducer is protected from the measurement environment. We describe the design, fabrication, implementation, and characterization using liquid medium. The sensor operates at a frequency of 185 MHz and has demonstrated a comparable sensitivity to other SAW in-liquid sensors, while offering quality factor (Q) value in water of about 250, low impedance and fairly low susceptibility to viscous damping. For proof of principle, sensing performance was evaluated by means of binding 40 nm neutravidin-coated SiO2 nanoparticles to a biotin-labeled lipid bilayer deposited over the reflectors. Frequency shifts were determined for every step of the affinity assay. Demonstration of this integrated technology highlights the potential of SAR technology for in-liquid sensing.

  8. Molecular composites based on high-performance polymers and an interpenetrating liquid crystal thermoset

    NARCIS (Netherlands)

    Dingemans, T.J.

    2014-01-01

    The invention is directed to a polymeric composition comprising a first polymer (in particular HPP) and a liquid crystal thermoset (LCT) network that interpenetrates said first polymer, which LCT network comprises LCT oligomers that are at least partly polymerized, as well as to a method for

  9. High performance electrochemical pseudocapacitors from ionic liquid assisted electrochemically synthesized p-type conductive polymer.

    Science.gov (United States)

    Ehsani, A; Mohammad Shiri, H; Kowsari, E; Safari, R; Torabian, J; Hajghani, S

    2017-03-15

    In this paper firstly, 1-methyl-3-methylimidazolium bromide (MB) as a new high efficient ionic liquid was synthesized using chemical approach and then fabricated POAP/MB films by electro-polymerization of POAP in the presence of MB to serve as the active electrode for electrochemical supercapacitor. Theoretical study (AIM) and electrochemical analysis have been used for characterization of ionic liquid and POAP/MB composite film. Different electrochemical methods including galvanostatic charge-discharge experiments, cyclic voltammetry and electrochemical impedance spectroscopy are carried out in order to investigate the performance of the system. This work introduces new most efficient materials for electrochemical redox capacitors with advantages including ease synthesis, high active surface area and stability in an aqueous electrolyte. Copyright © 2016 Elsevier Inc. All rights reserved.

  10. Measurement of lumefantrine and its metabolite in plasma by high performance liquid chromatography with ultraviolet detection

    DEFF Research Database (Denmark)

    Khalil, Insaf F; Abildrup, Ulla; Alifrangis, Lene H

    2011-01-01

    measurement of LUM and its major metabolite the desbutyl LUM (DL) in plasma. Halofantrine was used as an internal standard. Liquid-liquid extraction of samples was carried out using hexane-ethyl acetate (70:30, v/v). Chromatographic separation was carried out on a Synergi Polar-RP column (250 mm × 300 mm......, particle size 4 µm). The mobile phase consisted of acetonitrile-0.1M ammonium acetate buffer adjusted to pH 4.9 (85:15%, v/v). Absorbance of the compounds was monitored at 335 nm using a reference wavelength of 360 nm. Absolute extraction recovery for LUM and DL were 88% and 90%, respectively. Inter...

  11. Design and implementation of an automated liquid-phase microextraction-chip system coupled on-line with high performance liquid chromatography

    DEFF Research Database (Denmark)

    Li, Bin; Petersen, Nickolaj J.; Payán, María D Ramos

    2014-01-01

    An automated liquid-phase microextraction (LPME) device in a chip format has been developed and coupled directly to high performance liquid chromatography (HPLC). A 10-port 2-position switching valve was used to hyphenate the LPME-chip with the HPLC autosampler, and to collect the extracted....... The composition of the supported liquid membrane (SLM) and carrier was optimized in order to achieve reasonable extraction performance of all the five alkaloids. With 1-octanol as SLM solvent and with 25mM sodium octanoate as anionic carrier, extraction recoveries for the different opium alkaloids ranged between....... The repeatability was within 5.0-10.8% (RSD). The membrane liquid in the LPME-chip was regenerated automatically between every third injection. With this procedure the liquid membrane in the LPME-chip was stable in 3-7 days depending on the complexity of sample solutions with continuous operation. With this LPME...

  12. High Fidelity Simulation of Liquid Jet in Cross-flow Using High Performance Computing

    Science.gov (United States)

    Soteriou, Marios; Li, Xiaoyi

    2011-11-01

    High fidelity, first principles simulation of atomization of a liquid jet by a fast cross-flowing gas can help reveal the controlling physics of this complicated two-phase flow of engineering interest. The turn-around execution time of such a simulation is prohibitively long using typically available computational resources today (i.e. parallel systems with ~O(100) CPUs). This is due to multiscale nature of the problem which requires the use of fine grids and time steps. In this work we present results from such a simulation performed on a state of the art massively parallel system available at Oakridge Leadership Computing Facility (OLCF). Scalability of the computational algorithm to ~2000 CPUs is demonstrated on grids of up to 200 million nodes. As a result, a simulation at intermediate Weber number becomes possible on this system. Results are in agreement with detailed experiment measurements of liquid column trajectory, breakup location, surface wavelength, onset of surface stripping as well as droplet size and velocity after primary breakup. Moreover, this uniform grid simulation is used as a base case for further code enhancement by evaluating the feasibility of employing Adaptive Mesh Refinement (AMR) near the liquid-gas interface as a means of mitigating computational cost.

  13. Intact-protein trapping columns for proteomic analysis in capillary high-performance liquid chromatography.

    Science.gov (United States)

    Guan, Xia; Yan, Guoquan; Gao, Mingxia; Hong, Guangfeng; Deng, Chunhui; Zhang, Xiangmin

    2010-10-29

    A new type of monolithic trapping columns with high mechanical strength was prepared by thin-layer sol-gel coating method and applied to trapping intact proteins for on-line capillary liquid chromatography. Monolithic trapping columns were fabricated by entrapping C8 reversed-phase particles into the capillary columns through a sol-gel network, which was formed by hydrolysis and polycondensation of methyltriethoxysilane. Hundreds times of trapping/untrapping for intact proteins were carried out. The trapping columns showed long-term stability up to 300 bar. Recovery, loading capacity and reproducibility of trapping columns were evaluated using four proteins. The recovery of four protein mixtures for the C8 monolithic trapping columns was 99.3% on average. The loading capacity of 5 mm × 320 μm i.d. C8 trapping columns for the protein mixtures was 30 μg. Day-to-day relative standard deviation (RSD) values for recoveries of protein mixtures on the same C8 trapping column ranged from 2.34 to 5.87%, column-to-column RSD values were from 3.01 to 6.81%. The C8 trapping columns were used to trap normal mouse liver intact proteins in a capillary liquid chromatography system. Results demonstrated high efficiency of the monolithic trapping columns for trapping intact proteins for proteomic analysis in on-line capillary liquid chromatography system. Copyright © 2010 Elsevier B.V. All rights reserved.

  14. Determination of total phthalates in edible oils by high-performance liquid chromatography coupled with photodiode array detection.

    Science.gov (United States)

    Xie, Qilong; Sun, Dekui; Han, Yangying; Jia, Litao; Hou, Bo; Liu, Shuhui; Li, Debao

    2016-03-01

    The previously reported procedure for the determination of the total phthalate in fatty food involved the extraction of phthalates using chloroform/methanol followed by the removal of the solvents before alkaline hydrolysis requiring 20 h and derivatization of phthalic acid. In this study, a phase-transfer catalyst (tetrabutylammonium chloride) was used in the liquid-liquid heterogeneous hydrolysis of phthalates in oil matrix shortening the reaction time to within 25 min. The resulting phthalic acid in the hydrolysate was extracted by a novel molecular complex based dispersive liquid-liquid microextraction method coupled with back-extraction before high-performance liquid chromatography coupled with photodiode array detection. Under the optimal experimental conditions, the linearity of the method was in the range of 0.5-12 nmol/g with the correlation coefficients (r) >0.997. The detection limit (S/N = 3) was 0.11 nmol/g. Intraday and interday repeatability values expressed as relative standard deviation were 3.9 and 7.1%, respectively. The recovery rates ranged from 82.4 to 99.0%. The developed method was successfully applied for the analysis of total phthalate in seven edible oils. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Determination of drug lipophilicity by phosphatidylcholine-modified microemulsion high-performance liquid chromatography.

    Science.gov (United States)

    Xuan, Xueyi; Xu, Liyuan; Li, Liangxing; Gao, Chongkai; Li, Ning

    2015-07-25

    A new biomembrane-mimetic liquid chromatographic method using a C8 stationary phase and phosphatidylcholine-modified (PC-modified) microemulsion mobile phase was used to estimate unionized and ionized drugs lipophilicity expressed as an n-octanol/water partition coefficient (logP and logD). The introduction of PC into sodium dodecyl sulfate (SDS) microemulsion yielded a good correlation between logk and logD (R(2)=0.8). The optimal composition of the PC-modified microemulsion liquid chromatography (PC-modified MELC) mobile phase was 0.2% PC-3.0% SDS-6.0% n-butanol-0.8% ethyl acetate-90.0% water (pH 7.0) for neutral and ionized molecules. The interactions between the analytes and system described by this chromatographic method is more similar to biological membrane than the n-octanol/water partition system. The result in this paper suggests that PC-modified MELC can serve as a possible alternative to the shake-flask method for high-throughput unionized and ionized drugs lipophilicity determination and simulation of biological processes. Copyright © 2015 Elsevier B.V. All rights reserved.

  16. High performance red phosphorus electrode in ionic liquid-based electrolyte for Na-ion batteries

    Science.gov (United States)

    Dahbi, Mouad; Fukunishi, Mika; Horiba, Tatsuo; Yabuuchi, Naoaki; Yasuno, Satoshi; Komaba, Shinichi

    2017-09-01

    Electrochemical performance of the red phosphorus electrode was examined in ionic-liquid electrolyte, 0.25 mol dm-3 sodium bisfluorosulfonylamide (NaFSA) dissolved N-methyl-N-propylpyridinium-bisfluorosulfonylamide (MPPFSA), at room temperature. We compared its electrochemical performance to conventional EC/PC/DEC, EC/DEC, and PC solutions containing 1 mol dm-3 NaPF6. The electrode in NaFSA/MPPFSA demonstrated a reversible capacity of 1480 mAh g-1 and excellent capacity retention of 93% over 80 cycles, which is much better than those in the conventional electrolytes. The difference in capacity retention for the electrolytes correlates to the different solid electrolyte interphase (SEI) layer formed on the phosphorus electrode. To understand the SEI formation in NaFSA/MPPFSA and its evolution during cycling, we investigate the surface layer of the red phosphorus electrodes with hard X-ray photoelectron spectroscopy (HAXPES) and time-of-flight secondary ion mass spectrometry (TOF-SIMS). A detailed analysis of HAXPES spectra demonstrates that SEI layer consists of major inorganic and minor organic species, originating from decomposition of MPP+ and FSA-. Homogenous surface layer is formed during the first cycle in NaFSA/MPPFSA while in alkyl carbonate ester electrolytes, continuous growth of surface film up to the 20th cycle is observed. Possibility of red phosphorous electrode for battery applications with pure ionic liquid is discussed.

  17. Bimesogenic liquid crystals: new materials for high-performance photonics devices and displays

    Science.gov (United States)

    Coles, Harry J.

    2007-02-01

    We describe wide temperature range new bimesogenic nematic liquid crystals with high flexoelectro-optic coefficients (e/K),of the order of 1.5- 2.0 CN -1 m -1, high switching angles, > 100° and microsecond response times which may be used to give gray scale devices in both the ULH texture, with an optimum optical in plane switch of 45° at fields of 4Vμm -1 or less, and in the USH or Grandjean texture (with a unique optically isotropic "field off" black state and contrast ratios of > 1000:1), using "in plane" electric fields, with switching times of the order of 20μs. The new materials and devices give μs level to level switching and the real potential for colour filter free frame sequential colour switching. New highly reflective Blue Phase devices, stable over a 50°C temperature range, in which an electric field is used to switch the reflection from red to green, for example, will be described. Full RGB reflections may be obtained with switching times of a few milliseconds. Finally we will briefly mention potential applications including high efficiency RGB liquid crystal laser sources.

  18. High-performance liquid chromatographic resolution of oxamniquine enantiomers: application to in vitro metabolism studies.

    Science.gov (United States)

    Noctor, T A; Fell, A F; Kaye, B

    1990-01-01

    A method is described for the HPLC analysis of oxamniquine enantiomers in liver fraction incubates, using a second-generation alpha 1-acid glycoprotein-based column (Chiral-AGP). Oxamniquine is extracted from the incubation media by liquid-liquid extraction, using diethyl ether. The dried residue is redissolved in eluent, filtered, then injected directly onto the analytical column. The extraction method affords recoveries of oxamniquine of approximately 93%, at concentrations up to 525 micrograms/ml, with an average relative standard deviation of 5.9%. The limit of detection of the method (to give an SNR = 2 at 246 nm) is 0.3 ng on-column for the first eluting, laevorotatory enantiomer and 2.3 ng for the dextrorotatory isomer. The method allowed study of the depletion of oxamniquine enantiomers in liver postmicrosomal incubates. In the rat, a turnover of 21.9% was observed, with no apparent enantioselectivity. Similar observations were made for a mouse liver subcellular fraction incubation. The absence of enantioselectivity in this biotransformation may be attributable to the low substrate specificity of the oxidase or dehydrogenase enzymes involved.

  19. Validation of a technique by high-performance liquid chromatography for the determination of total isoflavones

    Directory of Open Access Journals (Sweden)

    Pilar A. Soledispa Cañarte

    2017-04-01

    Full Text Available Context: Isoflavones may act as selective regulators in the prevention of various diseases. The most important source of isoflavones is the soy, from which different phytotherapeutics are elaborated of use in Ecuadorian population. However, its concentration varies depending on several factors, therefore quality assessment need to be carried out through out several analytical methods. Aims: To validate an analytical method by high precision liquid chromatography (HPLC to quantify total isoflavones in herbal medicine. Methods: To quantify isoflavones, it was used a brand liquid chromatography with UV/VIS detector at 260 nm, C-18 column using isocratic method. The mobile phase was composed of 2% acetic acid: acetonitrile (75:25. The quantification was performed against reference standard. The parameters for the validation followed the established in the USP 33. Results: The chromatogram presented six peaks with elution between 1.557 and 18.913 min. The linearity of the system and the method got r2 equal to 0.98 and 0.99 respectively. The coefficients of variation 1.5% in the study of repetitiveness and 2% in intermediate precision. The accuracy of the adjusted lineal model exhibited r=0.95 and intercept reliable interval (-0.921; 1.743. Conclusions: The validated method was specific, accurate, precise and linear. It can be used for quality control and stability studies of isoflavones present in herbal medicine.

  20. High-performance liquid chromatographic determination of rivastigmine in human plasma for application in pharmacokinetic studies.

    Science.gov (United States)

    Amini, Hossein; Ahmadiani, Abolhassan

    2010-01-01

    A simple and reproducible HPLC method with spectrophotometric detection was developed for determination of rivastigmine in human plasma. Liquid-liquid extraction of rivastigmine and donepezil (as internal standard) from plasma samples was performed with 1-butanol/n-hexane (2:98 v/v) in alkaline condition followed by back-extraction into diluted acetic acid. Chromatography was carried out using a Silica column (250 mm × 4.6 mm, 5 μm) under isocratic elution with acetonitrile-50 mM aqueous sodium dihydrogen phosphate (17: 83 v/v, pH 3.1. Analyses were run at a flow-rate of 1.3 mL/min at of 50°C. The recovery was 90.8% and 95.7% for rivastigmine and the internal standard donepezil, respectively. The precision of the method was 2.6% to 9.1% over the concentration range of 0.5-16 ng/mL for rivastigmine in plasma with a linearity greater than 0.999. The method was specific and sensitive, with a quantification limit of 0.5 ng/mL and a detection limit of 0.2 ng/mL in plasma. The method was used for a bioequivalence study in healthy subjects.

  1. Analysis of biogenic amines in wines by salting-out assisted liquid-liquid extraction and high-performance liquid chromatography with fluorimetric detection.

    Science.gov (United States)

    Ramos, Rui Miguel; Valente, Inês Maria; Rodrigues, José António

    2014-06-01

    Biogenic amines are nitrogenous organic compounds of low molecular weight that are either formed or metabolized in cells of living organisms and can be found in several food products, being produced mainly by amino acid decarboxylation. When ingested in high concentrations they can induce several health problems in humans. In alcoholic beverages, and especially in wine, they are formed during the vinification process as a result of the action of microorganisms. In this work it is proposed a new methodology for the determination of biogenic amines in wines, which includes a sample preparation approach based on salting-out assisted liquid-liquid extraction, the use of dansyl chloride for the derivatization and chromatographic separation by high-performance liquid chromatography with fluorimetric detection. The salting-out effect is used to promote phase separation between water and a water-miscible organic solvent, while improving the extraction of organic or inorganic species. Several extraction parameters were optimized, such as the dansyl chloride concentration, pH and the effects caused by the order in which the extraction and derivatization were performed. Extraction of amines, and consequent detection, depends on the presence of dansyl chloride in solution prior to extraction. The results showed the possibility to simultaneously perform the extraction and the derivatization, making sample preparation easier and less time-consuming. The methodology was successfully applied to the determination of biogenic amines in five wines (white, red and rosé). This method has the potential to be a good alternative to existing methods since it is cheaper, easier and simplifies the sample preparation step. Copyright © 2014 Elsevier B.V. All rights reserved.

  2. Rapid determination of lipophilic vitamins in human serum by ultra-high performance liquid chromatography using a fluorinated column and high-throughput miniaturized liquid-liquid extraction.

    Science.gov (United States)

    Cervinkova, Barbora; Krcmova, Lenka Kujovska; Klabackova, Sava; Solichova, Dagmar; Solich, Petr

    2017-09-01

    A high-throughput miniaturized liquid-liquid extraction procedure followed by a simple ultra-high performance liquid chromatography method coupled with fluorescence detection for bioanalytical analysis of all tocopherol isomers and retinol in human serum has been developed and validated. In the extraction procedure, a synthetic internal standard tocol was used, which does not occur in the human body. The separation of structurally related vitamins was achieved using a new generation of pentafluorophenyl propyl core-shell stationary phase with elution using methanol and an aqueous solution of ammonium acetate. The fluorescence of retinol and tocopherol isomers was detected at λex  = 325, 295 nm and λem  = 480, 325 nm, respectively. The rapid baseline separation of all analytes was accomplished within 4.0 min. The sensitivity of method was demonstrated with lower limits of quantification: retinol 0.01 μM, α-tocopherol 0.38 μM, β-tocopherol 0.18 μM, γ-tocopherol 0.14 μM, and δ-tocopherol 0.01 μM. Possible application of this method in clinical practice was confirmed by the analysis of human serum samples from healthy volunteers. Finally, the simultaneous determination of retinol and all tocopherol isomers in human serum can enable the clarification of their role in metabolism and in diseases such as cancer. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Stability and Degradation of Caffeoylquinic Acids under Different Storage Conditions Studied by High-Performance Liquid Chromatography with Photo Diode Array Detection and High-Performance Liquid Chromatography with Electrospray Ionization Collision-Induced Dissociation Tandem Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Meng Xue

    2016-07-01

    Full Text Available Caffeoylquinic acids (CQAs are main constituents in many herbal medicines with various biological and pharmacological effects. However, CQAs will degrade or isomerize when affected by temperature, pH, light, etc. In this study, high-performance liquid chromatography with photodiode array detection (HPLC-PDA and high-performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS was utilized to study the stability and degradation of CQAs (three mono-acyl CQAs and four di-acyl CQAs under various ordinary storage conditions (involving different temperatures, solvents, and light irradiation. The results indicated that the stability of CQAs was mainly affected by temperature and light irradiation, while solvents did not affect it in any obvious way under the conditions studied. Mono-acyl CQAs were generally much more stable than di-acyl CQAs under the same conditions. Meanwhile, the chemical structures of 30 degradation products were also characterized by HPLC-MSn, inferring that isomerization, methylation, and hydrolysis were three major degradation pathways. The result provides a meaningful clue for the storage conditions of CQAs standard substances and samples.

  4. Identification of Ceftiofur Oxidation Products by High-Performance Liquid Chromatography/Electrospray Ionization/Tandem Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Hye-Sung Cho

    2011-03-01

    Full Text Available Oxidation products of ceftiofur were formed in hydrogen peroxide solution. The structures of the ceftiofur oxidationproducts were characterized by high-performance liquid chromatography/electrospray ionization/tandem mass spectrometry(HPLC/ESI/MS/MS. The products were identified as compounds oxidized at the sulfur of a cephem ring. For further analysis,experiments were performed using O18-labeled hydrogen peroxide. In addition, density-functional calculations were carried out forsix possible oxidation products to support the experimental results.

  5. Investigation into the temporal stability of aqueous standard solutions of psilocin and psilocybin using high performance liquid chromatography.

    Science.gov (United States)

    Anastos, N; Barnett, N W; Pfeffer, F M; Lewis, S W

    2006-01-01

    This paper reports an investigation into the temporal stability of aqueous solutions of psilocin and psilocybin reference drug standards over a period of fourteen days. This study was performed using high performance liquid chromatography utilising a (95:5% v/v) methanol: 10 mM ammonium formate, pH 3.5 mobile phase and absorption detection at 269 nm. It was found that the exclusion of light significantly prolonged the useful life of standards, with aqueous solutions of both psilocin and psilocybin being stable over a period of seven days.

  6. Simultaneous high performance liquid chromatographic analysis of vitamins B1, B2 and B6 in royal jelly

    OpenAIRE

    Presoto,Ana Elisa F; Rios,Magda D. G; Almeida-Muradian,Ligia B. de

    2004-01-01

    Royal jelly is used as a food supplement, popularly known as rich in B vitamins. The present work has two objectives: firstly, to apply simultaneous quantitative determination by High Performance Liquid Chromatography of thiamin (vitamin B1), riboflavin (vitamin B2) and pyridoxine (vitamin B6) and secondly to compare the obtained data with the Dietary Reference Intake (DRI) values. The values obtained showed no thiamin, a range from 20 to 171 ng g-1 of riboflavin and from 408 to 2 188 ng g-1 ...

  7. [Ultra-high performance liquid chromatography-mass spectrometry for analysis of newborn and fetal bovine serum components].

    Science.gov (United States)

    Li, Caixia; Wang, Fuke; Liu, Liu

    2014-05-01

    We used ultra-high performance liquid chromatography-mass spectrometry (UPLC/MS) for analyzing and identifying the active components of newborn calf serum (NCS) and fetal bovine serum (FBS). The results demonstrated significant differences in the components between NCS and FBS. FBS appeared to have more complex components than NCS, with mass to ratios (m/z) of the substances of 498, 273 and 448. These substances in FBS may be the main active components to support the proliferation and differentiation of cells.

  8. Determination of methyldibromoglutaronitrile in cosmetic products by high-performance liquid chromatography with electrochemical detection. Method validation

    DEFF Research Database (Denmark)

    Rastogi, Suresh Chandra; Zachariae, Claus; Johansen, Jeanne D

    2004-01-01

    An increased frequency of contact allergy to methyldibromoglutaronitrile (MDBGN), a commonly used preservative in cosmetics and other consumer products, has been reported in recent years. A high-performance liquid chromatography (HPLC) method for the determination of MDBGN in cosmetic products has...... been validated in the present study. The identification is performed by reductive electrochemical detection of the bromine present in the molecule. The method is suitable for compliance testing of cosmetic products as well as for the research to support clinical and epidemiological studies....

  9. One-pot preparation of a novel monolith for high performance liquid chromatography applications.

    Science.gov (United States)

    Jiao, Xiaoyan; Shen, Shigang; Shi, Tiesheng

    2015-12-15

    Various novel porous organic-based monoliths with the mode of hydrophobicity were synthesized by in situ free-radical crosslinking copolymerization and optimized for the separations of small molecules and high-performance reversed-phase chromatography (RP-chromatography). These monoliths contained co-polymers based on glycidyl methacrylate (GMA)/ethylene glycol dimethacrylate (EDMA)/tripropylene glycol diacrylate (TPGDA) or EDMA/TPGDA. A mixture of cetanol, methanol and poly (ethylene glycol) (PEG) was used as the porogen, with the ratio of these solvents being varied along with the polymerization temperature to generate a library of monoliths. The conditions were optimized and the resulting poly (GMA-co-TPGDA-co-EDMA) monolith was investigated by infrared spectrometer (IR), field emission scanning electron microscope (FESEM), and mercury intrusion porosimetry (MIP), respectively. The column performance was assessed by the separation of a series of neutral solutes of benzene derivatives. The result demonstrated that the prepared monolith exhibited an RP-chromatographic behavior and relatively homogeneous structure, good permeability and separation performance. Moreover, the relative standard deviations (RSDs) of the retention factor values for benzene derivatives were less than 1.5% (n=7, column-to-column). The approach used in this study was extended to the separation of anilines. Copyright © 2015 Elsevier B.V. All rights reserved.

  10. Electromembrane extraction of polar basic drugs from plasma with pure bis(2-ethylhexyl) phosphite as supported liquid membrane

    DEFF Research Database (Denmark)

    Huang, Chuixiu; Seip, Knut Fredrik; Gjelstad, Astrid

    2016-01-01

    Electromembrane extraction (EME) of polar basic drugs from human plasma was investigated for the first time using pure bis(2-ethylhexyl) phosphite (DEHPi) as the supported liquid membrane (SLM). The polar basic drugs metaraminol, benzamidine, sotalol, phenylpropanolamine, ephedrine...... were analyzed by high-performance liquid chromatography-ultraviolet detection (HPLC-UV). In contrast to other SLMs reported for polar basic drugs in the literature, the SLM of DEHPi was highly stable in contact with plasma, and the system-current across the SLM was easily kept below 50 μA. Thus...

  11. Determination of total L-Ascorbic Acid by high performance liquid chromatography in human plasma

    Directory of Open Access Journals (Sweden)

    Oveisi MR

    2001-07-01

    Full Text Available The total vitamin C content in human plasma is widely accepted as an indicator of the tissue status of vitamin C. A liquid chromatography method with ultraviolet detector (264 nm for measuring ascorbic acid in human plasma was developed. A C18 reversed-phase column and cetrimide as an ion-pairing agent was employed. Ascorbic acid (AA was measured after reducing L-dehydroascorbic acid to L-ascorbic acid with dithiothreitol. The stability of the ascorbic acid in plasma, metaphosphoric acid and trichloroacetic acid was also evaluated. The analytical parameters, including linearity (1-60 µg/ml, accuracy (98.98%, repeatability (2.8% and reproducibility (7.2%, showed that the method is reliable for measuring the total vitamin C content in plasma.

  12. Biocytin synthetase activity in human milk as assessed by high-performance liquid chromatography.

    Science.gov (United States)

    Oizumi, J; Hayakawa, K

    1993-01-29

    A reversed-phase liquid chromatographic assay for biocytin synthetase activity has been developed. By this method, biocytin synthetase, isolated to homogeneity from human milk, was found to synthetize biocytin from biotin and L-lysine in the presence of ATP and magnesium ion(s). Both ATP and magnesium ion(s) were required for the synthesis of biocytin. Equal molar amounts of ADP and ATP were produced and consumed, respectively, in the course of the production of the same molar amount of biocytin; however, production of AMP was not observed. Biocytin synthetase Michaelis constants were 2.5, 1.8, and 0.11 mM for biotin, L-lysine, and ATP, respectively. Biocytin synthetase from milk was shown to synthesize biocytin in a stoichiometric amount.

  13. HIGH PERFORMANCE TECHNOLOGIES FOR LIQUIDATION OF NON-OPERATIONAL PRODUCTION FACILITIES

    Directory of Open Access Journals (Sweden)

    V. N. Chernoivan

    2016-01-01

    Full Text Available The paper analyzes main reasons that have led to closure of a number of industrial enterprises on the territory of the Republic of Belarus and in the majority of former Soviet Union countries. An analysis of constructive decisions and range of bearing and enclosing structures for non-operational industrial buildings and facilities has been carried out in the paper. The analysis has made it possible to draw a conclusion that the overwhelming majority of the buildings and facilities were constructed using prefabricated and cast-in-situ reinforced concrete structures. Taking into account the facts that substantially all non-operational industrial buildings and facilities are located in industrial zones being rather far from residential housing area and having developed infrastructure (highways, railway lines, communication network etc. and expenses on infrastructure development usually exceed the cost of newly built industrial buildings and facilities some findings have been given on expediency pertaining to usage of existing industrial zones. The main problem has been defined in the paper and its solution will permit to use again existing industrial zones with non-operational industrial facilities which are located there. With due account for the executed analysis of standard operating procedures on liquidation of industrial buildings an expediency has been revealed that presupposes demolition of facilities with the help of mechanical breakdown. An economic efficiency on application of mechanical demolition method for industrial buildings constructed using prefabricated and cast-in-situ structures has been illustrated in Work Execution Plan on liquidation of industrial buildings in the workshop which has been involved in lime production at JSC “Berezovsky Industrial Complex of Silicate Products”. The proposed technology for mechanical demolition of reinforced concrete structures is based on application of a caterpillar excavating machine of

  14. Optimized method for the determination of itopride in human plasma by high-performance liquid chromatography with fluorimetric detection.

    Science.gov (United States)

    Ptácek, Pavel; Klíma, Josef; Macek, Jan

    2009-03-15

    A high-performance liquid chromatographic method with fluorescence detection for the determination of itopride in human plasma is reported. The sample preparation was based on liquid-liquid extraction of itopride from plasma with t-butylmethylether and dichloromethane (70:30, v/v) mixture followed by a back extraction of the analyte to the phosphate buffer (pH 3.2). Liquid chromatography was performed on an octadecylsilica column (55 mm x 4 mm, 3 microm particles), the mobile phase consisted of acetonitrile-triethylamine-15 mM dihydrogenpotassium phosphate (14.5:0.5:85, v/v/v), pH of the mobile phase was adjusted to 4.8. The run time was 3 min. The fluorimetric detector was operated at 250/342 nm (excitation/emission wavelength). Naratriptan was used as the internal standard. The limit of quantitation was 9.5 ng/ml using 0.5 ml of plasma. The method precision and inaccuracy were less than 8%. The assay was applied to the analysis of samples from a bioequivalence study.

  15. Highly conductive ionic liquids toward high-performance space-lubricating greases.

    Science.gov (United States)

    Fan, Xiaoqiang; Wang, Liping

    2014-08-27

    Although ionic liquids (ILs) as a class of promising materials have a wide range of applications due to the excellent properties, their potential as space lubricants has been not systematically explored. Here two kinds of conductive alkyl imidazolium ILs greases were prepared using 1-hexyl-3-methylimidazolium tetrafluoroborate (LB106) and 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl) amide (L-F106) as base oil and the polytetrafluoroethylene (PTFE) as thickener, with multiple-alkylated cyclopentane grease (MACs) as a comparison. Their chemical composition and tribological properties were investigated in detail under simulated space environment which is composed of high vacuum, high temperature and irradiation. Results show that the high conductive ILs greases not only possess good adaptive abilities to space environment and thermal stability but also provide excellent friction reducing and antiwear behaviors as well as high load carrying capacities. The unique physicochemical properties are attributed to a combination of special anions and cations, the excellent tribological properties are strongly dependent on a boundary protective film on the rubbing surfaces.

  16. [Determination of gossypol in edible vegetable oil with high performance liquid chromatography-tandem mass spectrometry].

    Science.gov (United States)

    Zhang, Wenhua; Huang, Chaoqun; Xie, Wen; Shen, Li

    2014-06-01

    A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for the determination of gossypol in edible vegetable oil. The sample was extracted with ethyl alcohol by vortex-excited oscillation. The extract was cleaned up by 0.22 microm filter membrane and centrifuged for 5 min at 4 000 r/min after standing in a fridge at 4 degrees C for 30 min. The compound was separated on a C18 column (100 mm x 2.1 mm, 3.5 microm) with acetonitrile and 1% (v/v) formic acid aqueous solution as mobile phase. The detection of gossypol was carried out by LC-MS/MS with positive electrospray ionization under multiple reaction monitoring (MRM) mode using external standard method. The limits of quantification (S/N > 10) of gossypol in edible vegetable oil was 1 mg/kg. The recoveries were from 87.4% to 100% at the spiked levels of 1, 2, 200 mg/kg of gossypol in edible vegetable oil with the relative standard deviations (RSDs) between 3.9% and 12.2%. The method, with high sensitivity, good precision and high recovery, was suitable for the confirmation and quantification of gossypol residue in edible vegetable oil.

  17. Three-dimensional graphitized carbon nanovesicles for high-performance supercapacitors based on ionic liquids.

    Science.gov (United States)

    Peng, Chengxin; Wen, Zubiao; Qin, Yao; Schmidt-Mende, Lukas; Li, Chongzhong; Yang, Shihe; Shi, Donglu; Yang, Jinhu

    2014-03-01

    Three-dimensional nanoporous carbon with interconnected vesicle-like pores (1.5-4.2 nm) has been prepared through a low-cost, template-free approach from petroleum coke precursor by KOH activation. It is found that the thin pore walls are highly graphitized and consist of only three to four layers of graphene, which endows the material with an unusually high specific surface area (2933 m(2)  g(-1) ) and good conductivity. With such unique structural characteristics, if used as supercapacitor electrodes in ionic liquid (IL) electrolytes, the graphitized carbon nanovesicle (GCNV) material displays superior performance, such as high energy densities up to 145.9 Wh kg(-1) and a high combined energy-power delivery, and an energy density of 97.6 Wh kg(-1) can be charged in 47 s at 60 °C. This demonstrates that the energy output of the GCNV-based supercapacitors is comparable to that of batteries, and the power output is one order of magnitude higher. Moreover, the synergistic effect of the GCNVs and the IL electrolyte on the extraordinary performance of the GCNV supercapacitors has been analyzed and discussed. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Determination of tropicamide in pharmaceutical formulations using high-performance liquid chromatography.

    Science.gov (United States)

    Amanlou, Massoud; Asmardi, Gholamreza; Andalibi, Pedram C; Javadi, Nahid; Khodadady, Farank; Omarny, Zinat Bahrampour

    2005-09-23

    An isocratic, reversed-phase liquid chromatographic method was developed for determination of tropicamide using atropine as an internal standard in a pharmaceutical dosage form. Tropicamide and atropine sulfate were separated using a microBondapak ODS (C18) column by isocratic elution of mobile phase with flow rate of 2.0 ml/min. The mobile phase composition was methanol-50 mM phosphate buffer (pH 4; 30:70, v/v). The eluate was monitored at 257 nm with detector range setting fixed at 0.01 AUFS. Under these conditions, the retention times were 4.81 min for atropine and 11.89 min for tropicamide. The standard calibration curve was linear over a sample concentration range from 2 to 300 microg/ml, with limit of detection of 0.15 microg/ml. The assay linearity was good (typically r2 = 0.9992) and the standard curves were linear in the detection range. The precision of the method (expressed by relative standard deviation) and the accuracy (mean error in percent) were tropicamide. The proposed method was satisfactorily applied to the determination of tropicamide in pharmaceutical preparation and stability indicating studies.

  19. Determination of fat-soluble vitamins in vegetable oils through microwave-assisted high-performance liquid chromatography.

    Science.gov (United States)

    Carballo, Silvia; Prats, Soledad; Maestre, Salvador; Todolí, José-Luis

    2015-04-01

    In this manuscript, a study of the effect of microwave radiation on the high-performance liquid chromatography separation of tocopherols and vitamin K1 was conducted. The novelty of the application was the use of a relatively low polarity mobile phase in which the dielectric heating effect was minimized to evaluate the nonthermal effect of the microwave radiation over the separation process. Results obtained show that microwave-assisted high-performance liquid chromatography had a shorter analysis time from 31.5 to 13.3 min when the lowest microwave power was used. Moreover, narrower peaks were obtained; hence the separation was more efficient maintaining or even increasing the resolution between the peaks. This result confirms that the increase in mobile phase temperature is not the only variable for improving the separation process but also other nonthermal processes must intervene. Fluorescence detection demonstrated better signal-to-noise compared to photodiode arrayed detection mainly due to the independent effect of microwave pulses on the baseline noise, but photodiode array detection was finally chosen as it allowed a simultaneous detection of nonfluorescent compounds. Finally, a determination of the content of the vitamin E homologs was carried out in different vegetable oils. Results were coherent with those found in the literature. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Molecularly imprinted solid-phase extraction for the selective determination of valnemulin in feeds with high performance liquid chromatography.

    Science.gov (United States)

    Guo, Hongbin; Liu, Kaiyong; Liu, Yahong; Fang, Binghu; Liu, Min; He, Limin; Zeng, Zhenling

    2011-01-15

    A simple, sensitive and reproducible high performance liquid chromatographic method was developed for determining valnemulin in feeds. Feed samples were extracted with ethyl acetate under alkaline condition, cleaned up by molecularly imprinted solid-phase extraction, and analyzed by high performance liquid chromatography with ultraviolet detection. The characteristics of the synthesized polymer were evaluated and the loading capacity of the polymer was about 1000 μg analyte/g imprinted polymer. The new procedure for the feed sample cleanup using the prepared polymer cartridge gave higher recoveries and fewer matrix interferences. The assay exhibited a linear dynamic range of 5.0-200 mg kg(-1) with the correlation coefficient above 0.9993. Recoveries of valnemulin from feed samples spiked at 5.0, 20 and 50 mg kg(-1) ranged between 76.0% and 94.4% with relative standard deviations of less than 9%. The limit of detection for valnemulin in feeds was 1 mg kg(-1). Copyright © 2010 Elsevier B.V. All rights reserved.

  1. Strategy for reduced calibration sets to develop quantitative structure-retention relationships in high-performance liquid chromatography.

    Science.gov (United States)

    Andries, Jan P M; Claessens, Henk A; Heyden, Yvan Vander; Buydens, Lutgarde M C

    2009-10-12

    In high-performance liquid chromatography, quantitative structure-retention relationships (QSRRs) are applied to model the relation between chromatographic retention and quantities derived from molecular structure of analytes. Classically a substantial number of test analytes is used to build QSRR models. This makes their application laborious and time consuming. In this work a strategy is presented to build QSRR models based on selected reduced calibration sets. The analytes in the reduced calibration sets are selected from larger sets of analytes by applying the algorithm of Kennard and Stone on the molecular descriptors used in the QSRR concerned. The strategy was applied on three QSRR models of different complexity, relating logk(w) or logk with either: (i) logP, the n-octanol-water partition coefficient, (ii) calculated quantum chemical indices (QCI), or (iii) descriptors from the linear solvation energy relationship (LSER). Models were developed and validated for 76 reversed-phase high-performance liquid chromatography systems. From the results we can conclude that it is possible to develop logP models suitable for the future prediction of retentions with as few as seven analytes. For the QCI and LSER models we derived the rule that three selected analytes per descriptor are sufficient. Both the dependent variable space, formed by the retention values, and the independent variable space, formed by the descriptors, are covered well by the reduced calibration sets. Finally guidelines to construct small calibration sets are formulated.

  2. High-performance liquid chromatographic assay of parabens in wash-off cosmetic products and foods using chemiluminescence detection

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Qunlin [Department of Chemistry, University of Science and Technology of China, Jinzai Road 96, Hefei, Anhui 230026 (China); Lian Mei [Department of Chemistry, University of Science and Technology of China, Jinzai Road 96, Hefei, Anhui 230026 (China); Liu Lijuan [Department of Chemistry, University of Science and Technology of China, Jinzai Road 96, Hefei, Anhui 230026 (China); Cui Hua [Department of Chemistry, University of Science and Technology of China, Jinzai Road 96, Hefei, Anhui 230026 (China)]. E-mail: hcui@ustc.edu.cn

    2005-04-29

    A new method for the simultaneous determination of parabens including methylparaben, ethylparaben, propylparaben, and butylparaben by high-performance liquid chromatography (HPLC) coupled with chemiluminescence detection was developed. The procedure was based on the chemiluminescent enhancement by parabens of the cerium(IV)-rhodamine 6G system in the strong sulfuric acid medium. The good separation of parabens was carried out with an isocratic elution using a mixture of methanol and water (60:40, v/v) within 8.5 min. Under the optimized conditions, a linear working range extends three orders of magnitude with the relative standard deviations of intra- and inter-day precision below 4.5%, and the detection limits were 1.9 x 10{sup -9}, 2.7 x 10{sup -9}, 3.9 x 10{sup -9}, and 5.3 x 10{sup -9} g ml{sup -1} for methylparaben, ethylparaben, propylparaben, and butylparaben, respectively. The chemiluminescence reaction was well compatible with the mobile phase of high-performance liquid chromatography. The proposed method has been successfully applied to the assay of parabens in wash-off cosmetic products and foods with the minimal sample preparation.

  3. Improved resins and novel materials and methods for solid phase extraction and high performance liquid chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Freeze, Ronald [Iowa State Univ., Ames, IA (United States)

    1997-10-08

    Solid-phase extraction (SPE) has grown to be one of the most widely used methods for isolation and preconcentration of a vast range of compounds from aqueous solutions. By modifying polymeric SPE resins with chelating functional groups, the selective uptake of metals was accomplished. The resin, along with adsorbed metals, was vaporized in the ICP and detection of the metals was then possible using either mass or emission spectroscopy. Drug analyses in biological fluids have received heightened attention as drug testing is on the increase both in sports and in the work environment. By using a direct-injection technique, biological fluids can be injected directly into the liquid chromatographic system with no pretreatment. A new surfactant, a sulfonated form of Brij-30 (Brij-S) is shown to prevent the uptake of serum proteins on commercial HPLC columns by forming a thin coating on the silica C18 surface. Excellent separations of eight or more drugs with a wide range of retention times were obtained. The separations had sharper peaks and lower retention times than similar separations performed with the surfactant sodium dodecylsulfate (SDS). Quantitative recovery of a number of drugs with limits of detection near 1 ppm with a 5 μl injection volume were obtained. Finally, a method for solid-phase extraction in a syringe is introduced. The system greatly reduced the volume of solvent required to elute adsorbed analytes from the SPE bed while providing a semi-automated setup. SPE in a syringe consists of a very small bed of resin-loaded membrane packed into a GC or HPLC syringe. After extraction, elution was performed with just a few μl of solvent. This small elution volume allowed injection of the eluent directly from the syringe into the chromatographic system, eliminating the handling problems associated with such small volumes.

  4. High-performance liquid chromatography method development for the quality control of Ginkgonis Semen

    Directory of Open Access Journals (Sweden)

    Vu Ngoc Han Le

    2017-09-01

    Full Text Available Ginkgonis Semen (GS is the seed of Ginkgo biloba Linné and a valuable material for herbal medicines and functional foods in China, Japan and Korea. The main bio-compounds of GS are GA, GB and GC like the leaves. There are many studies for the analysis of ginkgolides in the leaves or leaves extract of G. biloba because the leaves extract is a valuable material in pharmaceutical industries. However, there is no efficient analytical method for the quality control of GS based on the quantitation of ginkgolides because of matrix effect induced by different chemical composition. So, there are no content criteria of GS in Pharmacopoeia of Korea, Japan and China until now. This study aimed to develop HPLC method using ginkgolides based on the quantitation of GA, GB and GC for the quality control of GS with the optimization of sample preparation to enhance the analytical sensitivity and reproducibility. At first, defatting process using petroleum ether and liquid–liquid extraction were applied for sample preparation to remove matrix effect. The HPLC-ELSD method was developed with the mobile phase of a 0.5% aqueous acetic acid and methanol–acetonitrile solution (1:1 ratio under gradient conditions. GA, GB and GC contents in GS were different between Korea and China. The mean quantity of Korean samples was 4.85 ± 2.33 μg/g GA, 48.38 ± 5.10 μg/g GB, and 37.83 ± 7.64 μg/g GC. Those contents of Chinese samples were higher than Korean samples as 9.39 ± 2.51 μg/g GA, 123.59 ± 26.24 μg/g GB and 53.39 ± 4.97 μg/g GC. It indicated that the discrimination of GS between Korea and China could be achieved by marker compound contents. Furthermore, the geographical discrimination of GS between Korea and China was confirmed by PCA using the quantitative data of marker compounds. By statistical analysis, the calculated content criteria of GS by regression method were 2.35 μg/g of GA, 29.20 μg/g of GB, and 27.75 μg/g of GC, based on

  5. Analysis by high-performance liquid chromatography of teucrin A in beverages flavoured with an extract of Teucrium chamaedrys L.

    Science.gov (United States)

    Bosisio, E; Giavarini, F; Dell'Agli, M; Galli, G; Galli, C L

    2004-05-01

    Due to its liver toxicity, the medicinal use of germander (Teucrium chamaedrys L.) was banned in some countries. Nevertheless, alcoholic extracts are still permitted as flavour ingredients since they are fundamental in providing a bitter aromatic taste. Teucrin A represents the substance of major concern regarding the potential toxicity of germander. Hence, teucrin A represents the best analytical and toxicological marker of alcoholic extracts of T. chamaedrys. A sensitive high-performance liquid chromatography method to detect teucrin A in beverages is reported. Teucrin A was prepared by isolation from the plant extract using column chromatography and crystallization. The identity and purity (99%) were established by melting point, nuclear magnetic resonance and liquid chromatography-mass spectrometry. The high-performance liquid chromatography procedure was validated and its intra- and interday performance was established (relative standard deviation chamaedrys spiked with a range of concentrations of teucrin A. The limit of detection was 0.1 ppm and the limit of quantification was 0.3 ppm. Teucrin A accounted for about 70% of the neo-clerodane diterpenoids found in the total extract of a specimen of T. chamaedrys. The content (+/- standard deviation) in 18 batches of different geographical origin was 2338 +/- 740 ppm, per cent coefficient of variation = 32, minimum-maximum = 999 - 3445 ppm. The mean level of teucrin A in 10 bottles of the same brand was 6.1 +/- 0.8 ppm, per cent coefficient of variation = 12. In 10 different brands found on the Italian market, the content of teucrin A ranged from not detectable to 10 ppm.

  6. [Qualitative and quantitative analysis of amygdalin and its metabolite prunasin in plasma by ultra-high performance liquid chromatography-tandem quadrupole time of flight mass spectrometry and ultra-high performance liquid chromatography-tandem triple quadrupole mass spectrometry].

    Science.gov (United States)

    Gao, Meng; Wang, Yuesheng; Wei, Huizhen; Ouyang, Hui; He, Mingzhen; Zeng, Lianqing; Shen, Fengyun; Guo, Qiang; Rao, Yi

    2014-06-01

    A method was developed for the determination of amygdalin and its metabolite prunasin in rat plasma after intragastric administration of Maxing shigan decoction. The analytes were identified by ultra-high performance liquid chromatography-tandem quadrupole time of flight mass spectrometry and quantitatively determined by ultra-high performance liquid chromatography-tandem triple quadrupole mass spectrometry. After purified by liquid-liquid extraction, the qualitative analysis of amygdalin and prunasin in the plasma sample was performed on a Shim-pack XR-ODS III HPLC column (75 mm x 2.0 mm, 1.6 microm), using acetonitrile-0.1% (v/v) formic acid aqueous solution. The detection was performed on a Triple TOF 5600 quadrupole time of flight mass spectrometer. The quantitative analysis of amygdalin and prunasin in the plasma sample was performed by separation on an Agilent C18 HPLC column (50 mm x 2.1 mm, 1.7 microm), using acetonitrile-0.1% (v/v) formic acid aqueous solution. The detection was performed on an AB Q-TRAP 4500 triple quadrupole mass spectrometer utilizing electrospray ionization (ESI) interface operated in negative ion mode and multiple-reaction monitoring (MRM) mode. The qualitative analysis results showed that amygdalin and its metabolite prunasin were detected in the plasma sample. The quantitative analysis results showed that the linear range of amygdalin was 1.05-4 200 ng/mL with the correlation coefficient of 0.999 0 and the linear range of prunasin was 1.25-2 490 ng/mL with the correlation coefficient of 0.997 0. The method had a good precision with the relative standard deviations (RSDs) lower than 9.20% and the overall recoveries varied from 82.33% to 95.25%. The limits of detection (LODs) of amygdalin and prunasin were 0.50 ng/mL. With good reproducibility, the method is simple, fast and effective for the qualitative and quantitative analysis of the amygdalin and prunasin in plasma sample of rats which were administered by Maxing shigan decoction.

  7. Graphene-Analogues Boron Nitride Nanosheets Confining Ionic Liquids: A High-Performance Quasi-Liquid Solid Electrolyte.

    Science.gov (United States)

    Li, Mingtao; Zhu, Wenshuai; Zhang, Pengfei; Chao, Yanhong; He, Qian; Yang, Bolun; Li, Huaming; Borisevich, Albinab; Dai, Sheng

    2016-07-01

    Solid electrolytes are one of the most promising electrolyte systems for safe lithium batteries, but the low ionic conductivity of these electrolytes seriously hinders the development of efficient lithium batteries. Here, a novel class of graphene-analogues boron nitride (g-BN) nanosheets confining an ultrahigh concentration of ionic liquids (ILs) in an interlayer and out-of-layer chamber to give rise to a quasi-liquid solid electrolyte (QLSE) is reported. The electron-insulated g-BN nanosheet host with a large specific surface area can confine ILs as much as 10 times of the host's weight to afford high ionic conductivity (3.85 × 10(-3) S cm(-1) at 25 °C, even 2.32 × 10(-4) S cm(-1) at -20 °C), which is close to that of the corresponding bulk IL electrolytes. The high ionic conductivity of QLSE is attributed to the enormous absorption for ILs and the confining effect of g-BN to form the ordered lithium ion transport channels in an interlayer and out-of-layer of g-BN. Furthermore, the electrolyte displays outstanding electrochemical properties and battery performance. In principle, this work enables a wider tunability, further opening up a new field for the fabrication of the next-generation QLSE based on layered nanomaterials in energy conversion devices. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Speciation analysis of mercury in sediments using vortex-assisted liquid-liquid microextraction coupled to high-performance liquid chromatography-cold vapor atomic fluorescence spectrometry.

    Science.gov (United States)

    Leng, Geng; Yin, Hui; Li, Shaobo; Chen, Yong; Dan, Dezhong

    2012-09-15

    A simple and fast solvent microextraction method termed vortex-assisted liquid-liquid microextraction (VALLME) coupled with high-performance liquid chromatography-vapor generation atomic fluorescence spectrometry (HPLC-CVAFS) has been developed for the trace analysis of methylmercury (MeHg(+)), ethylmercury (EtHg(+)) and inorganic mercury (Hg(2+)) in sediment samples. Carbon tetrachloride was used as collecting solvent for the extraction of mercury species from sediment by a vortex-assisted extraction. In VALLME, 100 μL 1% (m/v) l-Cysteine were used as extraction solvent and were injected into 4 mL carbon tetrachloride. The extraction solvent dispersed into carbon tetrachloride under vigorously shaking by a vortex agitator. The fine droplets could extract mercury species within few minutes because of the shorter diffusion distance and larger specific surface area. After centrifugation, the floating extractant phase restored its initial single microdrop shape and was used for HPLC-CVAFS analysis. The parameters affecting the extraction efficiency of the proposed VALLME such as extraction solvent, vortex time, volumes of extraction solvent and salt addition etc. were investigated. Under the optimum conditions, linearity was found in the concentration range from 0.1 to 25 ng g(-1) for MeHg(+), 0.2 to 65 ng g(-1) for EtHg(+), and 0.1 to 30 ng g(-1) for Hg(2+). Coefficients of determination (R(2)) ranged from 0.9938 to 0.9972. The limits of detection (LODs, signal-to-noise ratio (S/N)=3) were 0.028 ng g(-1) for MeHg(+), 0.057 ng g(-1) for EtHg(+), and 0.029 ng g(-1) for Hg(2+). Reproducibility and recoveries were assessed by testing a series of 6 sediment samples, which were spiked with different concentration levels. Finally, the proposed method was successfully applied in analyses of real nature sediment samples. In this work, VALLME was applied to the extraction of mercury species in sediment samples for the first time. Using l-Cys as extraction solvent, the

  9. High-performance liquid chromatography with photodiode array detection and chemometrics method for the analysis of multiple components in the traditional Chinese medicine Shuanghuanglian oral liquid.

    Science.gov (United States)

    Li, Bao Qiong; Chen, Jing; Li, Jiao Jiao; Wang, Xue; Zhai, Hong Lin; Zhang, Xiao Yun

    2015-12-01

    Shuanghuanlian oral liquid, a traditional Chinese medicine preparation, is a mixture of three herbs (Flos Lonicerae, Radix Scutellariae and Fructus Forsythiae). In this study, the quantitative analysis of three main active compounds, chlorogenic acid, forsythin and baicalin in samples from different manufacturers was performed rapidly by high-performance liquid chromatography coupled with photodiode array detection followed by Contour Projection coupled to stepwise regression treatment of the obtained three-dimensional spectra in which the partial overlap between adjacent target components existed. The method was validated for linearity (R>0.9940), precision (RSDstepwise regression offered an accurate, simple, low-cost and eco-friendly way for the rapid quantitative analysis of Shuanghuanlian oral liquid samples. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Food safety evaluation: Detection and confirmation of chloramphenicol in milk by high performance liquid chromatography-tandem mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Nicolich, Rebecca S. [Dep Quimica Analitica-IQ/UFRJ, C. Tecnologia, BL A, Ilha do Fundao, Rio de Janeiro, RJ CEP 219749-970 (Brazil)]. E-mail: rebecca@ufrj.br; Werneck-Barroso, Eduardo [FIOCRUZ-SEFAR/IPEC, Av. Brasil, 4365, Manguinhos, Rio de Janeiro, RJ CEP 21040-900 (Brazil); Marques, Marlice A. Sipoli [Dep Quimica Analitica-IQ/UFRJ, C. Tecnologia, BL A, Ilha do Fundao, Rio de Janeiro, RJ CEP 219749-970 (Brazil)

    2006-04-13

    A simple and rapid procedure for extraction of chloramphenicol (CAP) in milk and analysis by high-performance liquid chromatography coupled with quadrupole mass spectrometry in tandem was developed. The method consisted of one step of liquid-liquid extraction using ethyl acetate and acidified water (10 mmol L{sup -1} formic acid) and HPLC-MS/MS detection. CAP-D5 was used as internal standard. The method was validated according to Commission Decision 2002/657/EC. The calibration curves were linear, with typical r {sup 2} values higher than 0.98. Absolute recovery of CAP from milk proved to be more than 95%, however CAP-D5 absolute recovery was 75%. The method was accurate and reproducible, being successfully applied to the monitoring of CAP in milk samples obtained from the Brazilian market. Decision limit (CC{alpha}) was 0.05 ng mL{sup -1} and detection capability (CC{beta}) was 0.09 ng mL{sup -1}.

  11. Simultaneous determination of six mycotoxins in peanut by high-performance liquid chromatography with a fluorescence detector.

    Science.gov (United States)

    Chen, Fangfang; Luan, Chuanlei; Wang, Lin; Wang, Shue; Shao, Lihua

    2017-04-01

    Mycotoxins, which may contaminate peanut and peanut products, are responsible for many diseases to humans. Aflatoxin B1 (AFB1), aflatoxin G1 (AFG1), aflatoxin B2 (AFB2), aflatoxin G2 (AFG2), ochratoxin A (OTA) and zearalenone (ZEN) are considered the most relevant groups of mycotoxins found in food. This work aimed to develop a high-performance liquid chromatography method with a fluorescence detector (HPLC-FLD) combined with dispersive liquid-liquid microextraction (DLLME) method for the simultaneous determination of the six mycotoxins in peanuts. The six mycotoxins were simultaneously determined under their best wavelength by means of changing wavelength. Under the optimum conditions, the linear ranges were 1-100 ng mL(-1) for AFB1, AFG1 and OTA, 0.3-30 ng mL(-1) for AFB2 and AFG2, 5-1000 ng mL(-1) for ZEN, with the correlation coefficient (R(2) ) of 0.9969-0.9997. Limits of detection (LODs) were 0.10, 0.10, 0.30, 0.03, 0.03 and 1.0 µg kg(-1) , respectively, and the mean recoveries were in the range of 83.1% to 99.3% with RSD mycotoxin. The proposed method was demonstrated to be simple, highly selective, accurate, reliable, and was successfully applied to simultaneously analyse the six mycotoxins in real peanut samples from China. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  12. Pharmacokinetics and Tissue Distribution Study of Praeruptorin D from Radix Peucedani in Rats by High-Performance Liquid Chromatography (HPLC

    Directory of Open Access Journals (Sweden)

    Xue Du

    2012-07-01

    Full Text Available Praeruptorin D (PD, a major pyranocoumarin isolated from Radix Peucedani, exhibited antitumor and anti-inflammatory activities. The aim of this study was to investigate the pharmacokinetics and tissue distribution of PD in rats following intravenous (i.v. administration. The levels of PD in plasma and tissues were measured by a simple and sensitive reversed-phase high-performance liquid chromatography (HPLC method. The biosamples were treated by liquid-liquid extraction (LLE with methyl tert-butyl ether (MTBE and osthole was used as the internal standard (IS. The chromatographic separation was accomplished on a reversed-phase C18 column using methanol-water (75:25, v/v as mobile phase at a flow rate of 0.8 mL/min and ultraviolet detection wave length was set at 323 nm. The results demonstrate that this method has excellent specificity, linearity, precision, accuracy and recovery. The pharmacokinetic study found that PD fitted well into a two-compartment model with a fast distribution phase and a relative slow elimination phase. Tissue distribution showed that the highest concentration was observed in the lung, followed by heart, liver and kidney. Furthermore, PD can also be detected in the brain, which indicated that PD could cross the blood-brain barrier after i.v. administration.

  13. Determination of ng/mL levetiracetam using ultra-high-performance liquid chromatography-photodiode absorbance.

    Science.gov (United States)

    Oláh, E; Bacsói, Gy; Fekete, J; Sharma, V K

    2012-03-01

    This paper demonstrates the analysis of levetiracetam, a new chiral antiepileptic drug, at ng/mL levels using an ultra-high-performance liquid chromatography (UHPLC)-photodiode absorbance (PDA) method. Three different sample preparation methods, liquid-liquid extraction with Extrelut, solid phase extraction (SPE) with Oasis HLB and Oasis MAX SPE cartridges, and protein precipitation with organic solvents were carried out. The last preparatory method is the simplest and provides the best recoveries: between 97.1% and 100.4% with RSD value below 5%. The column for separation is BEH C18 column (1.7 µm particle size and 100 × 2.1 mm i.d.) and acetonitrile-phosphate buffer (pH = 6.6; 0.01 M) (10/90 v/v) is the mobile phase. The results obtained are compared to analysis conducted by the HPLC method. The UHPLC method was validated in the range of 2-100 µg/mL levetiracetam concentration (R(2) = 0.9997). LOD and LOQ are 10 ng/mL and 33 ng/mL, respectively. The developed UHPLC method was applied to plasma samples of patient with epilepsy.

  14. Factors influencing the separation of oligonucleotides using reversed-phase/ion-exchange mixed-mode high performance liquid chromatography columns.

    Science.gov (United States)

    Biba, Mirlinda; Jiang, Eileen; Mao, Bing; Zewge, Daniel; Foley, Joe P; Welch, Christopher J

    2013-08-23

    New mixed-mode columns consisting of reversed-phase and ion-exchange separation modes were evaluated for the analysis of short RNA oligonucleotides (∼20mers). Conventional analysis for these samples typically involves using two complementary methods: strong anion-exchange liquid chromatography (SAX-LC) for separation based on charge, and ion-pair reversed-phase liquid chromatography (IP-RPLC) for separation based on hydrophobicity. Recently introduced mixed-mode high performance liquid chromatography (HPLC) columns combine both reversed-phase and ion-exchange modes, potentially offering a simpler analysis by combining the benefits of both separation modes into a single method. Analysis of a variety of RNA oligonucleotide samples using three different mixed-mode stationary phases showed some distinct benefits for oligonucleotide separation and analysis. When using these mixed-mode columns with typical IP-RPLC mobile phase conditions, such as ammonium acetate or triethylammonium acetate as the primary ion-pair reagent, the separation was mainly based on the IP-RPLC mode. However, when changing the mobile phase conditions to those more typical for SAX-LC, such as salt gradients with NaCl or NaBr, very different separation patterns were observed due to mixed-mode interactions. In addition, the Scherzo SW-C18 and SM-C18 columns with sodium chloride or sodium bromide salt gradients also showed significant improvements in peak shape. Copyright © 2013 Elsevier B.V. All rights reserved.

  15. A simple high-performance liquid chromatography for the determination of linezolid in human plasma and saliva.

    Science.gov (United States)

    Hara, Shuuji; Uchiyama, Masanobu; Yoshinari, Masami; Matsumoto, Taichi; Jimi, Shiro; Togawa, Atsushi; Takata, Tohru; Takamatsu, Yasushi

    2015-09-01

    Linezolid is an antimicrobial agent for the treatment of multiresistant Gram-positive infections. A practical high-performance liquid chromatography method was developed for the determination of linezolid in human plasma and saliva. Linezolid and an internal standard (o-ethoxybenzamide) were extracted from plasma and saliva with ethyl acetate and analyzed on a Capcell Pak C18 MG column with UV detection at 254 nm. The calibration curve was linear through the range 0.5-50 µg/mL using a 200 μL sample volume. The intra- and interday precisions were all saliva. The accuracies ranged from 98.8 to 110% for both matrices. The mean recoveries of linezolid were 80.8% for plasma and 79.0% for saliva. This method was used to determine the plasma and saliva concentrations of linezolid in healthy volunteers who were orally administered a 600 mg dose of linezolid. Our liquid-liquid extraction procedure is easy and requires a small volume of plasma or saliva (200 μL). This small volume can be advantageous in clinical pharmacokinetic studies, especially if children participate. Copyright © 2015 John Wiley & Sons, Ltd.

  16. Determination of Polycyclic Aromatic Hydrocarbons in Tea Infusions Samples by High Performance Liquid Chromatography with Fluorimetric Detection

    Directory of Open Access Journals (Sweden)

    Anna Maria Girelli

    2017-01-01

    Full Text Available This study focuses on the contamination of 15 polycyclic aromatic hydrocarbons (PAHs, recommended by the US Environmental Protection Agency, in 10 tea brands distributed in Italy. Analyses were carried out with a procedure based on saponification, liquid-liquid extraction, and PAHs determination by high performance liquid chromatography with fluorescence detector. A comparison with ultrasonic extraction in bath water was also reported. Contamination is expressed as the sum of analyzed PAHs and ranged between 347 and 4120 ng/L with a mean value of 1675 ng/L. PAHs with 3-4 rings were dominant with a contribution of 92%, while 7% and 1% were found for PAHs with 5 and 6 rings, respectively. Moreover, data revealed that three samples exceeded the EU 2008 criteria established for drinking water in which the sum of benzo[k]fluoranthene, benzo[b]fluoranthene, benzo[g,h,i]perylene, and indeno[1,2,3-cd]pyrene is considered (<100 ng/L and two samples exceeded the 10 ng/L level allowed for benzo[a]pyrene.

  17. Low-Cost High-Performance Non-Toxic Self-Pressurizing Storable Liquid Bi-Propellant Pressure-Fed Rocket Engine Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Exquadrum proposes a high-performance liquid bi-propellant rocket engine that uses propellants that are non-toxic, self-pressurizing, and low cost. The proposed...

  18. SEPARATION AND QUANTITATION OF NITROBENZENES AND THEIR REDUCTION PRODUCTS NITROANILINES AND PHENYLENEDIAMINES BY REVERSED=PHASE HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY

    Science.gov (United States)

    A reversed-phase high-performance liquid chromatographic method for the separation and quantitation of a mixture consisting of nitrobenzene, dinitrobenzene isomers, 1,3,5-trinitrobenzene and their reduction products: aniline, nitroanilines and phenylenediamines has been developed...

  19. Determination of rutin in cigarette tobacco, filters, mainstream smoke and burned ash of different branded cigarettes by high performance liquid chromatography

    National Research Council Canada - National Science Library

    Sun, Yinshi; Li, Wei; Wang, Jianhua; Bi, Jianjie; Su, Shudong

    2012-01-01

    ... and anti-protozoal properties. A high performance liquid chromatography method was used to analyze rutin in tobacco and filters, mainstream smoke, and burned ash of ten varieties of cigarettes made in China...

  20. Observation of different ceramide species from crude cellular extracts by normal-phase high-performance liquid chromatography coupled to atmospheric pressure chemical ionization mass spectrometry

    NARCIS (Netherlands)

    Pettus, BJ; Bielawska, A; Kroesen, BJ; Moeller, PDR; Szulc, ZM; Hannun, YA; Busman, M

    2003-01-01

    Normal-phase high-performance liquid chromatography (NP-HPLC) coupled to atmospheric pressure chemical ionization mass spectrometry (APCI-MS) allows qualitative analysis of endogenous ceramide and dihydroceramide species from crude lipid extracts utilizing chromatographic methods readily adaptable

  1. Direct high-performance liquid chromatographic enantioseparation of free α-, β- And γ-aminophosphonic acids employing cinchona-based chiral zwitterionic ion exchangers Amino Acid Analysis

    NARCIS (Netherlands)

    Gargano, Andrea F.G.; Kohout, Michal; Macíková, Pavla; Lämmerhofer, Michael; Lindner, Wolfgang

    2013-01-01

    We report a chiral high-performance liquid chromatographic enantioseparation method for free α-aminophosphonic, β-aminophosphonic, and γ-aminophosphonic acids, aminohydroxyphosphonic acids, and aromatic aminophosphinic acids with different substitution patterns. Enantioseparation of these synthons

  2. [Analysis of surface-active substances in Sapindus mukurossi by high performance liquid chromatography-mass spectrometry].

    Science.gov (United States)

    Wang, X C

    2001-11-01

    A high performance liquid chromatography-atmospheric pressure ionization mass spectrometry method has been developed for the analysis of surface-active substances (hederagenin saponins and sesquiterpene oligoglycosides) in the extracts of the pericarp of Sapindus mukurossi. The method consists of the separation of surface-active substances using C18 HPLC column, followed by detection using a diode-array detector at 210 nm and then on-line mass spectrometry. Hederagenin saponins and sesquiterpene oligoglycosides were characterized as [M - H]- or [M + Na]+. Based on the relative molecular mass, established by mass spectrometry and the structure induced by in-source CID technology, three components that had not been reported in Sapindus mukurossi before were identified. Several surface-active substances were obtained by means of semi-preparative HPLC. Their structures were further confirmed by NMR spectrometry as mukurozi-saponin Y2, mukurozi-saponin X, mukurozioside I a and mukurozioside II a.

  3. [Determination of serotonin in rat brain microdialysate after i. p. administration of fluoxetine hydrochloride by high performance liquid chromatography].

    Science.gov (United States)

    Guo, Yunzhen; Yu, Li; Ma, Zheng; Guo, Xingjie

    2007-03-01

    The concentration of serotonin (5-HT) in rat brain microdialysate before and after i. p. administration of fluoxetine hydrochloride was determined through precolumn derivatization by reversed-phase high performance liquid chromatography (RP-HPLC). A baseline separation of serotonin was achieved on a Hypersil C18 column (250 mm x 2. 0 mm, 5 microm) with acetonitrile-20 mmol/L sodium acetic solution (pH 5. 0) (45: 55, v/v) containing 20 mmol/L of sodium octanesulfonate as the mobile phase. Fluorescence detection with the excitation wavelength at 330 nm and emission wavelength at 455 nm was used for serotonin. There was good linear relationship between the peak area and concentration in the range of 0. 25 - 5. 0 nmol/L( r =0. 999 1). The limit of quantitation was 0. 25 nmol/L. The method is simple, accurate and can be applied to the determination of serotonin in biological specimen.

  4. Determination of Thiophanate-methyl in Tamoto by High Performance Liquid Chromatography-triple Quadrupole Tandem Mass Spectometry

    Directory of Open Access Journals (Sweden)

    XU Wei-feng

    2014-06-01

    Full Text Available To evaluate the safety of use of 70% thiophanate-methyl wettable powders in tomato, a supervised trial experiment was conducted to study the residues in tomato. A method of determining thiophanate-methyl by high performance liquid chromatography-tandem mass spectrometry(LC-MSMSwas established. Acetonitrile was used as an extraction solvent, and PSA and anhydrous magnesium were used for sample purifying. Samples were determined and quantified by LC-MSMS in the multiple reaction monitoring mode(MRM. The field trial recommended spraying 70% thiophanate-methyl WP on tomato with 562.5 gai· hm-2 in three times, which the safe interval was not less than three days from the last time to harvest. The results showed that the thiophanate methyl residue in tomato was lower than 0.05 mg· kg -1, both from field trials and market sampling samples.

  5. Determination of itopride hydrochloride by high-performance liquid chromatography with Ru(bpy)3(2+) electrogenerated chemiluminescence detection.

    Science.gov (United States)

    Sun, Yonghua; Zhang, Zhujun; Xi, Zhijun; Shi, Zuolong; Tian, Wei

    2009-08-26

    In this work, a stable electrogenerated chemiluminescence (ECL) detector was developed. The detector was prepared by packing cation-exchanged resin particles in a glass tube, followed by inserting Pt wires (working electrode) in this tube and sealing. The leakage of Ru(bpy)(3)(2+) can be compensated by adding a small amount of Ru(bpy)(3)(2+) into solution phase. Coupled with high-performance liquid chromatography separation, the detector has been used for determination of itopride hydrochloride in human serum. Under the optimal conditions, the ECL intensity has a linear relationship with the concentration of itopride hydrochloride in the range of 1.0 x 10(-8) g mL(-1) to 1.0 x 10(-6) g mL(-1) and the detection limit was 3 x 10(-9) g mL(-1) (S/N=3). The as-prepared ECL detector displayed good sensitivity and stability.

  6. Validation of high-performance liquid chromatography (HPLC method for quantitative analysis of histamine in fish and fishery products

    Directory of Open Access Journals (Sweden)

    B.K.K.K. Jinadasa

    2016-12-01

    Full Text Available A high-performance liquid chromatography method is described for quantitative determination and validation of histamine in fish and fishery product samples. Histamine is extracted from fish/fishery products by homogenizing with tri-chloro acetic acid, separated with Amberlite CG-50 resin and C18-ODS Hypersil reversed phase column at ambient temperature (25°C. Linear standard curves with high correlation coefficients were obtained. An isocratic elution program was used; the total elution time was 10 min. The method was validated by assessing the following aspects; specificity, repeatability, reproducibility, linearity, recovery, limits of detection, limit of quantification and uncertainty. The validated parameters are in good agreement with method and it is a useful tool for determining histamine in fish and fishery products.

  7. Simultaneous high-performance liquid chromatography assay of acetylsalicylic acid and salicylic acid in film-coated aspirin tablets.

    Science.gov (United States)

    Fogel, J; Epstein, P; Chen, P

    1984-12-28

    A reversed-phase high-performance liquid chromatography (HPLC) method has been developed for the simultaneous assay of acetylsalicylic acid (I) and salicylic acid (II) in film-coated aspirin tablets. As little as 0.1% II (relative to I) can be quantitatively determined. Using a 5-microns octadecylsilane column with water-acetonitrile-phosphoric acid (76:24:0.5) as the mobile phase enabled the chromatographic separation to be completed in 4 min. Due to the slow rate of decomposition of I to II in the extraction solvent, acetonitrile-methanol-phosphoric acid (92:8:0.5), the analysis of many samples was routinely performed by means of automated HPLC equipment. Other compounds (non-aspirin salicylates, caffeine and acetaminophen) were also separated by the chromatographic system.

  8. Application of high-performance liquid chromatography to the characterization of the betalain pigments in prickly pear fruits.

    Science.gov (United States)

    Fernández-López, J A; Almela, L

    2001-04-13

    The qualitative and quantitative betalain pigment content of two cultivars of prickly pear (Opuntia ficus-indica) fruits grown in southeastern Spain was evaluated. After methanolic extraction of crushed fruits, reversed-phase high-performance liquid chromatography and photodiode array detection were applied simultaneously for the separation, identification and quantification of these pigments. Two main pigments were obtained, which were identified as indicaxanthin (lambda(max) 484 nm) and betanin (lambda(max) 535 nm). Spectrophotometric evaluation of both pigments showed a yield of around 20-30 mg per 100 g of fresh pulp. When the influence of temperature (25 to 90 degrees C) on betacyanin pigment stability was investigated, the results revealed a substantial degree of thermodegradation at temperatures higher than 70 degrees C.

  9. Determination of the triglyceride composition of avocado oil by high-performance liquid chromatography using a light-scattering detector.

    Science.gov (United States)

    Hierro, M T; Tomás, M C; Fernández-Martín, F; Santa-María, G

    1992-08-28

    The triglyceride composition of avocado oil was determined by high-performance liquid chromatography using a light-scattering detector. Two avocado varieties, Fuerte and Hass, were analysed, and the qualitative composition of each was found to be similar, though quantitative differences were detected. The triglyceride composition was predicted using a system of equations based on the relationship between log k' and the molecular variables equivalent carbon number, chain length and number of double bonds for each of the fatty acids in the glycerides. A total of 24 molecular species of triglycerides were identified. The chromatographic system used successfully separated the critical pairs OOO-LOS, PaPaO-LnPP and PaOO-LOP (O = olein; L = linolein; S = stearin; Pa = palmitolein; Ln = linolenin; P = palmitin). Detector response was found to have a linear relationship with the amount of sample injected over the injection range 10-70 micrograms.

  10. Determination of levamisole and tetramisole in seized cocaine samples by enantioselective high-performance liquid chromatography and circular dichroism detection.

    Science.gov (United States)

    Bertucci, Carlo; Tedesco, Daniele; Fabini, Edoardo; Di Pietra, Anna Maria; Rossi, Francesca; Garagnani, Marco; Del Borrello, Elia; Andrisano, Vincenza

    2014-10-10

    Levamisole, an anthelmintic drug, has been increasingly employed as an adulterant of illicit street cocaine over the last decade; recently, the use of tetramisole, the racemic mixture of levamisole and its enantiomer dexamisole, was also occasionally observed. A new enantioselective high-performance liquid chromatography (HPLC) method, performed on cellulose tris(3,5-dimethylphenylcarbamate) chiral stationary phases in normal-phase mode, was validated to determine the enantiomeric composition of tetramisole enantiomers in seized cocaine samples. Furthermore, the hyphenation of the validated HPLC method with a circular dichroism (CD) detection system allowed the direct determination of elution order and a selective monitoring of levamisole and dexamisole in the presence of possible interferences. The method was applied to the identification and quantitation of the two enantiomers of tetramisole in seized street cocaine samples. Copyright © 2014 Elsevier B.V. All rights reserved.

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

    DEFF Research Database (Denmark)

    Lemnge, M M; Rønn, A; Flachs, H

    1993-01-01

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

  12. Rapid determination of Papaver somniferum alkaloids in process streams using monolithic column high-performance liquid chromatography with chemiluminescence detection

    Energy Technology Data Exchange (ETDEWEB)

    Costin, Jason W. [School of Life and Environmental Sciences, Deakin University, Geelong, Victoria 3217 (Australia); Lewis, Simon W. [Department of Applied Chemistry, Curtin University of Technology, Perth, WA 6845 (Australia); Purcell, Stuart D. [GlaxoSmithKline, Port Fairy, Victoria 3284 (Australia); Waddell, Lucy R. [GlaxoSmithKline, Port Fairy, Victoria 3284 (Australia); Francis, Paul S. [School of Life and Environmental Sciences, Deakin University, Geelong, Victoria 3217 (Australia); Barnett, Neil W. [School of Life and Environmental Sciences, Deakin University, Geelong, Victoria 3217 (Australia)]. E-mail: barnie@deakin.edu.au

    2007-07-30

    We have combined high-performance liquid chromatography (HPLC) separations using a monolithic column with acidic potassium permanganate and tris(2,2'-bipyridyl)ruthenium(II) chemiluminescence detection in a rapid and highly sensitive method to monitor the process of extracting opiate alkaloids from Papaver somniferum. Due to the high flow rates allowed with the monolithic column and the inherent selectivity of the chemiluminescence reactions, the four predominant alkaloids - morphine, codeine, oripavine and thebaine - were determined in less than 2 min. The results obtained with numerous process samples compared favourable with those of the standard HPLC methodology. Limits of detection were 1 x 10{sup -10} M, 5 x 10{sup -10} M, 5 x 10{sup -10} M and 1 x 10{sup -9} M, for morphine, codeine, oripavine and thebaine, respectively.

  13. IDENTIFICATION OF MYCOBACTERIUM GENAVENSE IN A DIANA MONKEY (CERCOPITHECUS DIANA) BY POLYMERASE CHAIN REACTION AND HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY.

    Science.gov (United States)

    Kelly, Kathleen M; Wack, Allison N; Bradway, Dan; Simons, Brian W; Bronson, Ellen; Osterhout, Gerard; Parrish, Nicole M; Montali, Richard J

    2015-06-01

    A 25-yr-old Diana monkey (Cercopithecus diana) with a 1.5-yr history of chronic colitis and diarrhea was found to have disseminated granulomatous disease with intralesional acid fast bacilli. Bacilli were identified as Mycobacterium genavense by polymerase chain reaction, sequencing of the 16S-23S ribosomal RNA intergenic spacer (ITS) gene, and mycolic acid analysis by high-performance liquid chromatography. Mycobacterium genavense is a common cause of mycobacteriosis in free-ranging and captive birds. In addition, recognition of opportunistic infection in human immunodeficiency virus-positive patients is increasing. Disease manifestations of M. genavense are similar to Mycobacterium avium complex (MAC) and include fever, wasting, and diarrhea with disseminated disease. Similar clinical signs and lesions were observed in this monkey. Mycobacterium genavense should be considered as a differential for disseminated mycobacterial disease in nonhuman primates as this agent can mimic MAC and related mycobacteria.

  14. Simultaneous determination of eight major bioactive compounds in Dachengqi Tang (DT by high-performance liquid chromatography

    Directory of Open Access Journals (Sweden)

    Chen Guanyuan

    2008-04-01

    Full Text Available Abstract Background Dachengqi Tang (DT is a common traditional Chinese medicine formula for expelling neire ('internal heat' in the stomach and intestines. There was no reliable analytical method available for the quality control of DT. Methods A high-performance liquid chromatography (HPLC method with a reverse phase C18 column (150 × 4.6 mm was developed. The mobile phase was methanol with 0.2% acetic acid. Eight markers including naringin, hesperidin, aloe emodin, rhein, honokiol, magnolol, emodin and chrysophanol were determined. Results Regression analysis revealed a linear relationship between the concentrations of the markers and the peak area ratio of the standards and internal standard. The limit of detection (S/N = 3 and the limit of qualification (RSD Conclusion A reliable HPLC method for simultaneous determination of the eight markers in DT was developed.

  15. Sensitive determination of specific radioactivity of positron emission tomography radiopharmaceuticals by radio high-performance liquid chromatography with fluorescence detection.

    Science.gov (United States)

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

    2008-10-01

    A sensitive quality control method is often required in positron emission tomography (PET) radiopharmaceutical analysis due to the high specific radioactivity of synthetic products. The applicability of a radio high-performance liquid chromatography (HPLC) method with fluorescence detection was evaluated for a wide variety of PET radiopharmaceuticals. In 29 different radiopharmaceuticals studied, 20 compounds exhibited native fluorescence. These properties enabled sensitive determination of their chemical masses by direct fluorimetric detection after separation by HPLC. For some substances, detection limits were below nanograms per milliliter level, at least 40 times better than current UV absorbance detection. Sufficient reproducibility and linearity were obtained for the analysis of pharmaceutical fluid. Post-column fluorimetric derivatization was also established for the quantitative determination of FDG and ClDG in [(18)F]FDG samples. These methods could be applied successfully to the analysis of PET radiopharmaceuticals with ultra-high specific radioactivity.

  16. High-performance liquid chromatography analysis of black currant (Ribes nigrum L.) fruit phenolics grown either conventionally or organically.

    Science.gov (United States)

    Anttonen, Mikko J; Karjalainen, Reijo O

    2006-10-04

    Black currants (Ribes nigrum L.) contain a diverse range of phenolics and possess a high antioxidant activity, which makes them an interesting target for the functional food industry. In this study, phenolic profiles of organically and conventionally grown black currant fruits, collected from commercial farms within a climatically similar area, were compared. Compounds were identified using UV/vis and mass spectroscopy techniques and quantified with high-performance liquid chromatography equipped with UV/vis detection. Several different conjugates of hydroxycinnamic acids, flavonols, and anthocyanins were quantified. Statistically significant differences between farms were found for almost all compounds. Differences between the highest and the lowest measured values of major phenolic compounds of different phenolic classes ranged from 24 to 77%. Principal component analysis quite effectively separated farms from each other but did not cluster them according to cultivation technique. Thus, it was concluded that the biochemical quality of organically grown black currant fruits does not differ from those grown conventionally.

  17. The isolation and purification of glucoraphanin from broccoli seeds by solid phase extraction and preparative high performance liquid chromatography.

    Science.gov (United States)

    Rochfort, Simone; Caridi, Domenico; Stinton, Melanie; Trenerry, V Craige; Jones, Rod

    2006-07-07

    Plant foods contain not only essential nutrients, e.g. protein, amino acids, vitamins and minerals, but also phytochemicals that have added health benefits. One such class of phytochemicals are the glucosinolates. Glucosinolates, particularly glucoraphanin, are predominant in plants of the Brassica genus, most notably in vegetables such as broccoli. There is a growing interest in the role glucoraphanin plays in chemoprotection and as a result there is a requirement to accurately determine the levels of glucoraphanin in vegetable products. Reverse phase ion pair high performance liquid chromatography (HPLC) is the method of choice; however, this work has been hindered by the lack of available standard reference materials. Broccoli seeds, which are particularly rich in glucoraphanin (20-50 mg/g), have proved to be ideal for the isolation of glucoraphanin on the preparative scale. A novel preparative scale HPLC method with simple compound recovery has been developed to meet the need for a glucoraphanin standard.

  18. Analysis of native human plasma proteins and haemoglobin for the presence of bityrosine by high-performance liquid chromatography

    DEFF Research Database (Denmark)

    Daneshvar, B; Frandsen, H; Dragsted, L O

    1997-01-01

    fluorescent substance, bityrosine. High-performance liquid chromatography (HPLC) analysis of acid hydrolyzed serum albumin after oxidation with peroxidase/H2O2 or with Cu++/H2O2 showed that bityrosine had been formed whereas oxidation of this protein with Fe(III)/ascorbate did not result in the formation......Generation of reactive oxygen species in vivo results in oxidative-damage to cellular components, including proteins. Due to the relatively long half-lives of several blood proteins the cumulative formation of oxidatively damaged proteins might serve as a biomarker for reactive oxygen species...... of bityrosine. Bityrosine could not be detected in human plasma proteins or haemoglobin with the detection limit of one pmol per mg protein....

  19. Reversed-phase high-performance liquid chromatographic measurement of the P-aminobenzoic acid synthesized by Streptococcus sanguis.

    Science.gov (United States)

    Zhou, X D; Hu, T; Zhang, P; Tan, H

    1998-09-01

    This study investigated the biosynthesis of P-aminobenzoic acid by Streptococcus sanguis and the role of P-aminobenzoic acid in the interaction between Streptococcus sanguis and Streptococcus mutans. A reversed-phase high-performance liquid chromatographic technique was used to analyze the P-aminobenzoic acid synthesized by Streptococcus sanguis in an anaerobic atmosphere. The results showed, that (1) the chromatographic method established in this study had good linear relation and the average recovery of P-aminobenzoic acid was 80%, and (2) Streptococcus sanguis did synthesize P-aminobenzoic acid, and the mean concentration of P-aminobenzoic acid was 1.23 micrograms/mL. The results of this study will help further studies of the factors that may have effects on P-aminobenzoic acid synthesis by Streptococcus sanguis and on the role of P-aminobenzoic acid in the microbial homeostasis of dental plaque.

  20. Determination of undecylenic and sorbic acids in cosmetic preparations by high performance liquid chromatography with electrochemical detection.

    Science.gov (United States)

    Bousquet, Ennio; Spadaro, A; Santagati, N A; Scalia, S; Ronsisvalle, G

    2002-11-07

    A highly sensitive and selective method for the determination of sorbic (SA) and undecylenic acid (UA) in cosmetic formulations by a high performance liquid chromatography method with electrochemical detection (ECD) is described. The pre-column derivatizations of SA and UA and the internal standard (cyclohexanoic acid (cHA)) were carried out using 1-(2,5-dihydroxyphenyl)-2-bromoethanone (2,5-DBE) as an electroactive labeling reagent previously synthesized in our lab. The resulting electroactive esters were separated by isocratic elution of a 5 micrometer Hypersil CN column with acetonitrile-acetate buffer eluent. The compounds were detected by a porous graphite electrode set at an oxidation potential of +0.45 V. The analytical method developed in this study is suitable for quality control assays of complex cosmetic formulations containing sorbic and/or UA.

  1. REVERSED-PHASE HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY STUDY OF LIPOPHILICITY OF IMIDAZO[2,1-F]THEOPHYLLINE DERIVATIVES.

    Science.gov (United States)

    Zagórska, Agnieszka; Czopek, Anna; Pełka, Karolina; Bajda, Marek; Stanisz-Wallis, Krystyna; Pawłowski, Maciej

    2015-01-01

    The present study is a part of our physicochemical and pharmacological studies in a group of tricyclic theophylline derivatives. The investigated compounds exhibit different pharmacological profiles in comparison to theophylline and have been tested as potential antidepressant and/or antipsychotic agents. The differences in pharmacological action between theophylline and their tricyclic derivatives can be explained by their various physicochemical properties, especially lipophilicity. The chromatographic behavior of twenty three derivatives of imidazo[2,1-ƒ]theophylline was investigated, using reversed-phase high performance liquid chromatography (RP-HPLC) method. Moreover, partition coefficients and selected pharmacokinetic parameters were calculated computationally. Principal component analysis (PCA) method was used to establish the relationship between obtained experimental and computational parameters.

  2. L-ascorbic acid losses in Kenyan vegetables during cooking as determined by high performance liquid chromatography

    Directory of Open Access Journals (Sweden)

    N.M.N. Wekesa

    2001-06-01

    Full Text Available The loss of L-ascorbic acid (L-AA in 14 different cooked local vegetables found in Nairobi markets was determined by high performance liquid chromatography. The effect of quantity of water on the loss of L-AA during cooking was studied with cowpea leaves. It was found that more L-AA was lost when larger amount of water was used than when smaller amount was used. The effect of the sharpness of the knife on the loss of L-AA was studied with spinach. It was found that more loss of L-AA occurred when a blunt (edge thickness 0.08 cm knife was used for cutting the vegetables than when a sharp knife (edge thickness 0.04 cm was used during cooking. L-AA was also determined when vegetables were cooked in different size pieces (surface are >1 cm2

  3. Hypoxanthine and xanthine concentrations determined by high performance liquid chromatography in biological fluids from patients with xanthinuria.

    Science.gov (United States)

    Boulieu, R; Bory, C; Baltassat, P; Divry, P

    1984-09-15

    In the present paper, we report the biochemical features of six cases of xanthinuria. For these studies, the concentrations of hypoxanthine and xanthine have been measured in urine, plasma and also erythrocyte samples by a rapid, sensitive high performance liquid chromatographic (HPLC) method. The analyses of plasma and erythrocyte samples require a very sensitive method relative to physiological concentrations and rigorous sampling conditions in order to achieve accurate results. In the cases reported in the literature, total oxypurine levels (hypoxanthine + xanthine) have been generally measured in plasma and urine by an enzymatic spectrophotometric method. In our studies, using HPLC, we found that xanthine is the major oxypurine compound in plasma and urine samples from patients with xanthinuria. In erythrocytes, a biological sample which has not been analysed up to now, we found that xanthine is present at high concentrations whereas it is not detectable in erythrocytes from healthy subjects.

  4. Bromfenac ophthalmic solution 0.09 %: human aqueous humor concentration detected by high-performance liquid chromatography.

    Science.gov (United States)

    Macrì, Angelo; Vagge, Aldo; Salis, Annalisa; Fucile, Carmen; Marini, Valeria; Martelli, Antonietta; Giuffrida, Sebastiano; Iester, Michele; Damonte, Gianluca; Mattioli, Francesca

    2017-04-01

    The purpose of this study was to evaluate the aqueous humor concentrations of bromfenac ophthalmic solution 0.09 % in patients undergoing phacoemulsification. Patients requiring cataract extraction received one drop (50 µL) of bromfenac 0.09 % solution in the eye to be operated, before bedtime the day before surgery or the morning of the surgery. The last administration was recorded. At the time of paracentesis, an aqueous humor sample was collected with a 30-gauge needle attached to a TB syringe and was later analyzed by high-performance liquid chromatography for drug concentration. 188 treated volunteers and 48 control, untreated, subjects were included in the study. The mean aqueous concentration of bromfenac in the treated group was 37.60 ± 68.86 and 0 nM (nmol/L) in the control group (p humor up to about 12 h after instillation.

  5. Determination of gouty arthritis' biomarkers in human urine using reversed-phase high-performance liquid chromatography

    Directory of Open Access Journals (Sweden)

    Lei-Wen Xiang

    2014-04-01

    Full Text Available Creatinine, uric acid, hypoxanthine and xanthine are important diagnostic biomarkers in human urine for gouty arthritis or renal disease diacrisis. A simple method for simultaneous determination of these biomarkers in urine based on reversed-phase high-performance liquid chromatography (RP-HPLC with ultraviolet (UV detector was proposed. After pretreatment by dilution, centrifugation and filtration, the biomarkers in urine samples were separated by ODS-BP column by elution with methanol/50 mM NaH2PO4 buffer solution at pH 5.26 (5:95. Good linearity between peak areas and concentrations of standards was obtained for the biomarkers with correlation coefficients in the range of 0.9957–0.9993. The proposed analytical method has satisfactory repeatability (the recovery of data in a range of creatinine, uric acid, hypoxanthine and xanthine was 93.49–97.90%, 95.38–96.45%, 112.46–115.78% and 90.82–97.13% with standard deviation of <5%, respectively and the limits of detection (LODs, S/N≥3 for creatinine, uric acid, hypoxanthine, and xanthine were 0.010, 0.025, 0.050 and 0.025 mg/L, respectively. The established method was proved to be simple, accurate, sensitive and reliable for the quantitation of gouty arthritis' biomarkers in human urine samples. The ratio of creatinine to uric acid was found to be a possible factor for assessment of gouty arthritis. Keywords: Gouty arthritis, Creatinine, Uric acid, Hypoxanthine, Xanthine, High-performance liquid chromatography

  6. Simple and sensitive high performance liquid chromatographic method for the simultaneous quantitation of the phenylalanine in human plasma

    Directory of Open Access Journals (Sweden)

    Hossein Danafar

    2015-09-01

    Full Text Available Phenylalanine (Phe is the most reliable indicator for the diagnosis of phenylketonuria (PKU. The purpose of this study is to establish a reliable and quick method for the assignment of Phe in peripheral capillary blood from newborns and children by high performance liquid chromatography with ultraviolet detection (HPLC-UV. PKU is an inborn error of metabolism characterized by the inability of the body to use Phe. A rapid and sensitive high performance liquid chromatographic (HPLC method has been developed for determination of Phe in plasma. The method uses a protein precipitation step with sulfosalicilic acid for sample preparation by separation on a Nova-pack C18 column using sodium acetate buffer and acetonitrile (94: 6 v/v adjusted to pH 6.5 with glacial acetic acid. The eluted peaks detected by a UV detector was set at wavelength of 215 nm. The method was validated in the range of Phe concentrations from 0.1 to 20 µg/ml. The limits of detection (LOD and quantitation (LOQ of the method were 0.05 and 0.1 µg/ml, respectively. The average drug recovery from plasma was 88.60 percent throughout the linear concentration range., with the average within-run and between-run accuracy values of 103.3 and 115.350, respectively. The method is quick, easy, very steady and precise for the screen, assignment, and evaluation of Phe in human plasma by HPLC, which is particularly a useful way for screening and diagnosis of PKU and monitoring of a diet therapy.

  7. Analytical Method Validation of High-Performance Liquid Chromatography and Stability-Indicating Study of Medroxyprogesterone Acetate Intravaginal Sponges

    Directory of Open Access Journals (Sweden)

    Nidal Batrawi

    2017-02-01

    Full Text Available Medroxyprogesterone acetate is widely used in veterinary medicine as intravaginal dosage for the synchronization of breeding cycle in ewes and goats. The main goal of this study was to develop reverse-phase high-performance liquid chromatography method for the quantification of medroxyprogesterone acetate in veterinary vaginal sponges. A single high-performance liquid chromatography/UV isocratic run was used for the analytical assay of the active ingredient medroxyprogesterone. The chromatographic system consisted of a reverse-phase C18 column as the stationary phase and a mixture of 60% acetonitrile and 40% potassium dihydrogen phosphate buffer as the mobile phase; the pH was adjusted to 5.6. The method was validated according to the International Council for Harmonisation (ICH guidelines. Forced degradation studies were also performed to evaluate the stability-indicating properties and specificity of the method. Medroxyprogesterone was eluted at 5.9 minutes. The linearity of the method was confirmed in the range of 0.0576 to 0.1134 mg/mL ( R 2 > 0.999. The limit of quantification was shown to be 3.9 µg/mL. Precision and accuracy ranges were found to be %RSD <0.2 and 98% to 102%, respectively. Medroxyprogesterone capacity factor value of 2.1, tailing factor value of 1.03, and resolution value of 3.9 were obtained in accordance with ICH guidelines. Based on the obtained results, a rapid, precise, accurate, sensitive, and cost-effective analysis procedure was proposed for quantitative determination of medroxyprogesterone in vaginal sponges. This analytical method is the only available method to analyse medroxyprogesterone in veterinary intravaginal dosage form.

  8. Analysis of therapeutic proteins and peptides using multiangle light scattering coupled to ultra high performance liquid chromatography.

    Science.gov (United States)

    Espinosa-de la Garza, Carlos E; Miranda-Hernández, Mariana P; Acosta-Flores, Lilia; Pérez, Néstor O; Flores-Ortiz, Luis F; Medina-Rivero, Emilio

    2015-05-01

    Analysis of the physical properties of biotherapeutic proteins is crucial throughout all the stages of their lifecycle. Herein, we used size-exclusion ultra high performance liquid chromatography coupled to multiangle light scattering and refractive index detection systems to determine the molar mass, mass-average molar mass, molar-mass dispersity and hydrodynamic radius of two monoclonal antibodies (rituximab and trastuzumab), a fusion protein (etanercept), and a synthetic copolymer (glatiramer acetate) employed as models. A customized instrument configuration was set to diminish band-broadening effects and enhance sensitivity throughout detectors. The customized configuration showed a performance improvement with respect to the high-performance liquid chromatography standard configuration, as observed by a 3 h column conditioning and a higher resolution analysis in 20 min. Analysis of the two monoclonal antibodies showed averaged values of 148.0 kDa for mass-average molar mass and 5.4 nm for hydrodynamic radius, whereas for etanercept these values were 124.2 kDa and 6.9 nm, respectively. Molar-mass dispersity was 1.000 on average for these proteins. Regarding glatiramer acetate, a molar mass range from 3 to 45 kDa and a molar-mass dispersity of 1.304 were consistent with its intrinsic peptide diversity, and its mass-average molar mass was 10.4 kDa. Overall, this method demonstrated an accurate determination of molar mass, overcoming the difficulties of size-exclusion chromatography. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Determination of plasma and brain levels of isotretinoin in mice following single oral dose by high-performance liquid chromatography.

    Science.gov (United States)

    Yang, Yongsheng; Faustino, Patrick J; Pine, P Scott; Davis, Hirsch; Grunberg, Neil; Phillips, Jennifer; Lyon, Robbe C; Yu, Lawrence X; Ciavarella, Anthony B; Del Grosso, Alfred V; Hanig, Joseph P

    2005-02-07

    An isocratic reversed-phase high-performance liquid chromatographic method was established and validated according to FDA's Guidance for Industry, "Bioanalytical Method Validation", for the determination of isotretinoin in plasma and brain tissue from mice following single and multiple oral doses of Accutane. Plasma sample preparation included deproteination with acetonitrile-perchloric acid followed by centrifugation. Brain tissue was homogenized and extracted with acetonitrile-perchloric acid followed by centrifugation. The supernatants were analyzed by high-performance liquid chromatography (HPLC). Benz[alpha]anthrancene-7,12-dione was used as the internal standard. Chromatographic separation was achieved on a C18 column using an acetonitrile-aqueous 0.5% acetic acid (85:15, v/v) elution. The average extraction efficiency was >95% for plasma and >82% for brain. The lower limit of quantification was 30 ng/mL for plasma and was 30 ng/0.1g for brain tissue, respectively. The linear range for plasma was 30-600 ng/mL, and 15-300 ng/0.1g for brain. Maximum concentrations of isotretinoin in both plasma and brain were observed at 1h after single oral dosing (25 mg/kg). The maximum concentrations in plasma and brain were 2.36 microg/mL and 0.34 microg/g, respectively. The mean area under curve (AUC) in plasma was 6.13 microg h/mL. The mean eliminate half-life in plasma was estimated as 46 min.

  10. Validation of high-performance liquid chromatographic method for analysis of fluconazole in microemulsions and liquid crystals

    Directory of Open Access Journals (Sweden)

    Hilris Rocha e Silva

    2014-04-01

    Full Text Available In recent decades, there has been a significant increase in the incidence of fungal diseases. Certain fungal diseases cause cutaneous lesions and in the usual treatment, generally administred orally, the drug reaches the site of action with difficulty and its concentration is too low. An approach much explored in recent years is the development of nanotechnology-based drug delivery systems, and microemulsions (ME and liquid crystals (LC are promising. ME and LC were developed with oleic acid or copaiba oil as the oil phase, propoxyl (5OP ethoxyl (20 OE cetyl alcohol as surfactant and water. An analytical method to assess the incorporation of fluconazole (FLU in the systems under study was validated according to guidelines of the International Conference on Harmonization (ICH guidelines and the Brazilian Food, Drug and Sanitation Agency (ANVISA. The method was conducted on a C18-RP column (250 × 4.6 mm i.d., maintained at room temperature. The mobile phase consisted of acetonitrile and water (50:50, v/v, run at a flow rate of 1.0mL/min and using ultraviolet detection at 210nm. The chromatographic separation was obtained with a retention time of 6.3min, and was linear in the range of 20-400 µg/mL (r2=0.9999. The specificity showed no interference of the excipients. The accuracy was 100.76%. The limits of detection and quantitation were 0.057 and 0.172 µg.mL-1, respectively. Moreover, method validation demonstrated satisfactory results for precision and robustness. The proposed method was applied for the analysis of the incorporation of FLU in ME and LC, contributing to improve the quality control and to assure the therapeutic efficacy.

  11. Development of a functionalized polymeric ionic liquid monolith for solid-phase microextraction of polar endocrine disrupting chemicals in aqueous samples coupled to high-performance liquid chromatography.

    Science.gov (United States)

    Feng, Juanjuan; Sun, Min; Bu, Yanan; Luo, Chuannan

    2015-09-01

    Ionic liquids (ILs) have been efficiently used as a "designer sorbent" in sample preparation. A novel 1-(3-aminopropyl)-3-(4-vinylbenzyl)imidazolium 4-styrenesulfonate IL monomer was synthesized and copolymerized with 1,6-di(3-vinylimidazolium) hexane bishexafluorophosphate IL as cross-linking agent to prepare a cross-linked polymeric ionic liquids (PILs) monolith. Coupled to high-performance liquid chromatography (HPLC), the PILs monolith was used as a solid-phase microextraction (SPME) sorbent to extract some polar endocrine disrupting chemical (EDCs) such as estrogens, bisphenol A, and phthalate esters in aqueous samples. Preparation and extraction conditions were investigated and optimized to obtain satisfactory extraction efficiency. Limits of detection (LODs) of the proposed method for three steroid estrogens and bisphenol A were 0.25 and 0.2 μg L(-1), respectively, which were lower than or comparable to some other sample preparation methods. Intra- and inter-day repeatability for all the analytes was 2.2-12%. The monolith-to-monolith repeatability was 7.4-15%. The extraction performance of the method for analysis of target estrogens in treated domestic wastewater was investigated and compared with a dispersive liquid-liquid microextraction (DLLME) method. The proposed SPME method provided better sensitivity and higher resistance to matrix interferences.

  12. Matrix solid-phase dispersion coupled with homogeneous ionic liquid microextraction for the determination of sulfonamides in animal tissues using high-performance liquid chromatography.

    Science.gov (United States)

    Wang, Zhibing; He, Mengyu; Jiang, Chunzhu; Zhang, Fengqing; Du, Shanshan; Feng, Wennan; Zhang, Hanqi

    2015-12-01

    Matrix solid-phase dispersion coupled with homogeneous ionic liquid microextraction was developed and applied to the extraction of some sulfonamides, including sulfamerazine, sulfamethazine, sulfathiazole, sulfachloropyridazine, sulfadoxine, sulfisoxazole, and sulfaphenazole, in animal tissues. High-performance liquid chromatography was applied to the separation and determination of the target analytes. The solid sample was directly treated by matrix solid-phase dispersion and the eluate obtained was treated by homogeneous ionic liquid microextraction. The ionic liquid was used as the extraction solvent in this method, which may result in the improvement of the recoveries of the target analytes. To avoid using organic solvent and reduce environmental pollution, water was used as the elution solvent of matrix solid-phase dispersion. The effects of the experimental parameters on recoveries, including the type and volume of ionic liquid, type of dispersant, ratio of sample to dispersant, pH value of elution solvent, volume of elution solvent, amount of salt in eluate, amount of ion-pairing agent (NH4 PF6 ), and centrifuging time, were evaluated. When the present method was applied to the analysis of animal tissues, the recoveries of the analytes ranged from 85.4 to 118.0%, and the relative standard deviations were lower than 9.30%. The detection limits for the analytes were 4.3-13.4 μg/kg. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Measurement of aflatoxin M1 in milk by ultra-high-performance liquid chromatography/tandem mass spectrometry.

    Science.gov (United States)

    Chen, Wen-Ling; Hsu, Tzu-Fang; Chen, Chia-Yang

    2011-01-01

    A sensitive method was developed using ultra-high-performance liquid chromatography (UHPLC)/MS/MS with positive electrospray ionization for determining aflatoxin M1 (AFM1) in milk and milk powder. A 50 mL quantity of low-fat liquid milk containing 100 ng/L AFM1, was prepared using immunoaffinity columns with a mean recovery rate of 79% (n = 3). UHPLC columns (BEH C18, BEH HILIC, and HSS T3) greatly reduced the chromatographic time and lowered the instrumental detection limits (IDLs) 16 to 58 times compared to an HPLC column (Betabasic C18). The HSS T3 column was chosen because it provided a low IDL (0.11 pg) and the lowest ion suppression of signal intensity (63.4%) among the tested columns. Matrix-fortified calibration curves were used for quantification and showed good linearity (r > 0.997) at 0.05-500 ng/mL. The LOD was 0.18 ng/kg for milk and 2.08 nglkg for milk powder, based on the signal intensity of the confirmatory product ion (m/z 259.1), which was less abundant than the quantitative product ion (m/z 273.1). Certified reference materials of milk powder at three levels (measured within a day and between days; the results were all close to the certified levels with low variations (RSDs < 15%), showing good precision and accuracy.

  14. High performance liquid chromatography with mid-infrared detection based on a broadly tunable quantum cascade laser.

    Science.gov (United States)

    Beskers, Timo F; Brandstetter, Markus; Kuligowski, Julia; Quintás, Guillermo; Wilhelm, Manfred; Lendl, Bernhard

    2014-05-07

    This work introduces a tunable mid-infrared (mid-IR) external cavity quantum cascade laser (EC-QCL) as a new molecular specific detector in liquid chromatography. An EC-QCL with a maximum tunability of 200 cm(-1) (1030-1230 cm(-1)) was coupled to isocratic high performance liquid chromatography (HPLC) for the separation of sugars with a cation exchange column (counter ion: Ca(2+)) and distilled water as the mobile phase. Transmission measurements in a 165 μm thick flow cell allowed for on-line coupling and independent quantification of glucose, fructose and sucrose in the concentration range from 5 mg mL(-1) to 100 mg mL(-1) in several beverages. The results obtained with the EC-QCL detector were found to be in good agreement with those obtained using a differential refractive index detector as a reference. The standard deviation of the method for the linear calibration was better than 5 mg mL(-1) for all sugars and reached a minimum of 1.9 mg mL(-1), while the DRI detector reached a minimum of 1 mg mL(-1). Besides the quantification of sugars for which a calibration was performed, also chromatographic peaks of other components could be identified on the basis of their IR absorption spectra. This includes taurine, ethanol, and sorbitol.

  15. Simple and rapid high-performance liquid chromatographic method for the determination of aspartame and its metabolites in foods.

    Science.gov (United States)

    Gibbs, B F; Alli, I; Mulligan, C N

    1996-02-23

    A method for the determination of aspartame (N-L-alpha-aspartyl-L-phenylalanine methyl ester) and its metabolites, applicable on a routine quality assurance basis, is described. Liquid samples (diet Coke, 7-Up, Pepsi, etc.) were injected directly onto a mini-cartridge reversed-phase column on a high-performance liquid chromatographic system, whereas solid samples (Equal, hot chocolate powder, pudding, etc.) were extracted with water. Optimising chromatographic conditions resulted in resolved components of interest within 12 min. The by-products were confirmed by mass spectrometry. Although the method was developed on a two-pump HPLC system fitted with a diode-array detector, it is straightforward and can be transformed to the simplest HPLC configuration. Using a single-piston pump (with damper), a fixed-wavelength detector and a recorder/integrator, the degradation of products can be monitored as they decompose. The results obtained were in harmony with previously reported tedious methods. The method is simple, rapid, quantitative and does not involve complex, hazardous or toxic chemistry.

  16. [Identification of triacylglycerols in coix oil by high performance liquid chromatography-atmospheric pressure chemical ionization-mass spectrometry].

    Science.gov (United States)

    Xiang, Zhi-Min; Zhu, Ming; Chen, Bi-Lian; Chen, Yong

    2005-09-01

    To identify triacylglycerols in coix oil. High performance liquid chromatography-atmospheric pressure chemical ionization-mass spectrometry was used for identification. The experiment was operated under the conditions: spray voltage at 3 000 V, capillary temperature at 250 degrees C, APCI vaporizer temperature at 400 degrees C, and corona current of 4 microA. Sheath gas pressure (high purity liquid nitrogen) was 35 kPa. Mass spectra were obtained over the m/e range of 300 to 900 amu, scan duration of 1s and Q1 peak width at 0.7. The stationary phase was Zorbax Extend C18 column (4.6 mm x 250 mm, 5 microm). The mobile phase: dichloromethane-acetonitrile (35:65), flow rate: 1 mL x min(-1); column temperature: 25 degrees C. 12 triacylglycerols were identified by HPLC-MS method. The result can be used to identify the components in a fingerprint chromatogram of coix oil and its related injection product.

  17. [Comparison of the determination results of gentamycin C components by high performance liquid chromatography with different detectors].

    Science.gov (United States)

    Li, Wei; Hu, Changqin; Wang, Mingjuan

    2007-07-01

    The results were compared for determining gentamycin C components by high per-formance liquid chromatography with different detectors in pharmacopoeias. Evaporative light-scattering detector (ELSD) was first used in Pharmacopoeia of People's Republic of China (ChP) 2005, while British Pharmacopoeia (BP) 2005 adopted pulsed amperometric detector in quantitative analysis of gentamycin. As gentamycin C components could not produce signals using UV detector, pre-column derivatization method made the detection possible, referring to United State Pharmacopoeia (USP) 29th Ed, etc. However, the absorbance of by-products and reagents overlapped with gentamycin C components, which caused much trouble in integrating peaks. That is the reason that the quantitative results were calculated based on area and height in different editions of ChP. To make the determination more accurate, "pure" chromatogram was resolved by heuristic evolving latent projection (HELP) method, based on calculating the data obtained with high performance liquid chromatography-diode array detection (HPLC-DAD) using pre-column derivatization with o-phthalic aldehyde (OPA). After subtracting the interference of impurities, gentamycin C1 component in samples was quantitatively determined accurately. The results were comparable to what achieved with HPLC-evaporative light-scattering detector and column switching. At the same time, it was proved that the HPLC-ELSD method in ChP 2005 was more reliable than the pre-column derivatization method.

  18. Multiclass determination of phytochemicals in vegetables and fruits by ultra high performance liquid chromatography coupled to tandem mass spectrometry.

    Science.gov (United States)

    Alarcón-Flores, María Isabel; Romero-González, Roberto; Vidal, José Luis Martínez; Frenich, Antonia Garrido

    2013-11-15

    In this study a simultaneous determination of several classes of phytochemicals (isoflavones, glucosinolates, flavones, flavonols and phenolic acids) in tomato, broccoli, carrot, eggplant and grape has been carried out by ultra high performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS). Solid-liquid extraction assisted by rotary agitator was utilised, using a mixture of methanol:water (80:20, v/v) as solvent. The analytical procedure was validated in all the matrices, obtaining recoveries ranging from 60% to 120% with repeatability values (expressed as relative standard deviations, RSDs) lower than 25%. Limits of quantification (LOQs) were always equal or lower than 50μg/kg, except for some glucosinolates (125μg/kg). Finally the method was applied to different matrices such as tomato, broccoli, carrot, grape and eggplant, observing that chlorogenic acid was detected in most of the samples at higher concentrations in relation to the other compounds. Copyright © 2013 Elsevier Ltd. All rights reserved.

  19. Liquid-liquid extraction combined with high performance liquid chromatography-diode array-ultra-violet for simultaneous determination of antineoplastic drugs in plasma

    Directory of Open Access Journals (Sweden)

    Ananda Lima Sanson

    2011-06-01

    Full Text Available A liquid-liquid extraction (LLE combined with high-performance liquid chromatography-diode array detection method for simultaneous analysis of four chemically and structurally different antineoplastic drugs (cyclophosphamide, doxorubicin, 5-fluorouracil and ifosfamide was developed. The assay was performed by isocratic elution, with a C18 column (5 µm, 250 x 4.6 mm and mobile phase constituted by water pH 4.0- acetonitrile-methanol (68:19:13, v/v/v, which allowed satisfactory separation of the compounds of interest. LLE, with ethyl acetate, was used for sample clean-up with recoveries ranging from 60 to 98%. The linear ranges were from 0.5 to 100 µg mL-1, for doxorubicin and 1 to 100 µg mL-1, for the other compounds. The relative standard deviations ranged from 5.5 to 17.7%. This method is a fast and simple alternative that can be used, simultaneously, for the determination of the four drugs in plasma, with a range enabling quantification of the drugs in pharmacokinetics, bioequivalence and therapeutic drug-monitoring studies.Um método de extração líquido-líquido (ELL combinado com cromatografia líquida de alta eficiência-detector de arranjo de diodos foi desenvolvido para análise simultânea de quatro fármacos antineoplásicos quimicamente e estruturalmente diferentes (ciclofosfamida, doxorrubicina, fluoruracila e ifosfamida. O estudo foi realizado sob condições isocráticas, com coluna C18 (5µm, 250 x 4.6 mm e fase móvel constituída por água pH 4.0-acetonitrila-metanol (68:19:13, v/v/v, que permitiu separação satisfatória dos analitos de interesse. A ELL, com acetato de etila, foi utilizada para limpeza da amostra, com recuperação variando de 60 a 98%. As faixas foram lineares de 0,5 a 100 µg mL-1 para doxorrubicina e 1 a 100 µg mL-1 para os outros compostos. O desvio padrão relativo variou de 5,5 a 17,7%. Este método é uma alternativa rápida e simples que pode ser usado, simultaneamente, para a determinação dos

  20. Determination of metabolite of nicergoline in human plasma by high-performance liquid chromatography and its application in pharmacokinetic studies

    Directory of Open Access Journals (Sweden)

    Rong Zheng

    2012-02-01

    Full Text Available A fast, simple and sensitive high performance liquid chromatographic (HPLC method has been developed for determination of 10α-methoxy-6-methyl ergoline-8β-methanol (MDL, a main metabolite of nicergoline in human plasma. One-step liquid–liquid extraction (LLE with diethyl ether was employed as the sample preparation method. Tizanidine hydrochloride was selected as the internal standard (IS. Analysis was carried out on a Diamonsil ODS column (150 mm×4.6 mm, 5 μm using acetonitrile–ammonium acetate (0.1 mol/L (15/85, v/v as mobile phase at detection wavelength of 224 nm. The calibration curves were linear over the range of 2.288–73.2 ng/mL with a lower limit of quantitation (LLOQ of 2.288 ng/mL. The intra- and inter-day precision values were below 13% and the recoveries were from 74.47% to 83.20% at three quality control levels. The method herein described was successfully applied in a randomized crossover bioequivalence study of two different nicergoline preparations after administration of 30 mg in 20 healthy volunteers. Keywords: Nicergoline, 10α-methoxy-6-methylergoline-8β-methanol (MDL, HPLC, Plasma-drug concentration, Bioequivalence study

  1. Determination of alkenes in cracking products by normal-phase high-performance liquid chromatography-diode array detection.

    Science.gov (United States)

    Tomić, Tatjana; Babić, Sandra; Nasipak, Nada Uzorinac; Ruszkowski, Maja Fabulić; Skrobonja, Livijana; Kastelan-Macan, Marija

    2009-05-01

    Alkene content determinations in fluid catalytic cracking (FCC) liquid products were performed by means of normal-phase high-performance liquid chromatography (NP-HPLC) with diode array detection (UV/DAD). Separation of alkenes from aromatic hydrocarbons was performed on amino-modified silica gel column with n-heptane as mobile phase. The column has a little affinity to alkenes and saturated hydrocarbons and a pronounced affinity to aromatic compounds. The problem of alkenes and saturates co-elution on this column type was overcome with the detection system, UV/DAD, sensitive and selective to alkenes, while saturates are inactive in UV field. Total alkene content was determined as a sum of mono- and dialkene groups quantified by external standard method. Validation and verification of the developed method proved their applicability. The following criteria were used to validate the HPLC-DAD method: selectivity, linearity, precision, limits of detection and quantification. Alkene contents were quantified with the external standard method of wide calibration range, so both low and high alkene contents can be determined by the single calibration. Correlation coefficients were higher than 0.99. Precision was evaluated as repeatability and intermediary precision with relative standard deviations less than 5%. Some structural investigation of alkene groups was performed to confirm the assumption. Proposed method was compared with certified NMR method. Six commercial motor gasoline samples were analyzed by these two methods. Obtained results indicate good agreement between alkene content determined by both methods. The developed method was applied to the determination of alkene content in liquid FCC products in the boiling range from 70 degrees C to 190 degrees C.

  2. Validation of a high-performance liquid chromatography/fluorescence detection method for the simultaneous quantification of fifteen polycyclic aromatic hydrocarbons

    DEFF Research Database (Denmark)

    Hansen, Åse Marie; Olsen, I L; Holst, E

    1991-01-01

    A high-performance liquid chromatography/fluorescence method using multiple wavelength shift for simultaneous quantification of different PAH compounds was developed. The new method was superior to the methods of DONG and GREENBERG [J. Liquid Chromatogr. 11, 1887-1905 (1988)] and WISE et al. [Pol...

  3. Determination of muscimol and ibotenic acid in Amanita mushrooms by high-performance liquid chromatography and liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Tsujikawa, Kenji; Kuwayama, Kenji; Miyaguchi, Hajime; Kanamori, Tatsuyuki; Iwata, Yuko; Inoue, Hiroyuki; Yoshida, Takemi; Kishi, Tohru

    2007-06-01

    A reliable analytical method was developed for the quantification and identification of muscimol (MUS) and ibotenic acid (IBO), the toxic constituents of Amanita muscaria and Amanita pantherina. MUS and IBO were extracted from mushrooms by aqueous methanol and derivatized with dansyl chloride (DNS-Cl). After extraction with ethyl acetate and evaporation of the solvent, the residue was ethylated with 1.25 M hydrogen chloride in ethanol. The resulting derivatives were quantified by high-performance liquid chromatography with UV detection and identified by liquid chromatography electrospray ionization tandem mass spectrometry. Calibration curves were linear in the range of 25-2500 ppm for MUS and 40-2500 ppm for IBO, respectively. This method was successfully applied to identify and quantify MUS and IBO in Amanita mushrooms naturally grown and circulated in the drug market.

  4. Determination of sunset yellow and tartrazine in food samples by combining ionic liquid-based aqueous two-phase system with high performance liquid chromatography.

    Science.gov (United States)

    Sha, Ou; Zhu, Xiashi; Feng, Yanli; Ma, Weixing

    2014-01-01

    We proposed a simple and effective method, by coupling ionic liquid-based aqueous two-phase systems (IL-ATPSs) with high performance liquid chromatography (HPLC), for the analysis of determining tartrazine and sunset yellow in food samples. Under the optimized conditions, IL-ATPSs generated an extraction efficiency of 99% for both analytes, which could then be directly analyzed by HPLC without further treatment. Calibration plots were linear in the range of 0.01-50.0 μg/mL for both Ta and SY. The limits of detection were 5.2 ng/mL for Ta and 6.9 ng/mL for SY. This method proves successful for the separation/analysis of tartrazine and sunset yellow in soft drink sample, candy sample, and instant powder drink and leads to consistent results as obtained from the Chinese national standard method.

  5. Determination of Sunset Yellow and Tartrazine in Food Samples by Combining Ionic Liquid-Based Aqueous Two-Phase System with High Performance Liquid Chromatography

    Directory of Open Access Journals (Sweden)

    Ou Sha

    2014-01-01

    Full Text Available We proposed a simple and effective method, by coupling ionic liquid-based aqueous two-phase systems (IL-ATPSs with high performance liquid chromatography (HPLC, for the analysis of determining tartrazine and sunset yellow in food samples. Under the optimized conditions, IL-ATPSs generated an extraction efficiency of 99% for both analytes, which could then be directly analyzed by HPLC without further treatment. Calibration plots were linear in the range of 0.01–50.0 μg/mL for both Ta and SY. The limits of detection were 5.2 ng/mL for Ta and 6.9 ng/mL for SY. This method proves successful for the separation/analysis of tartrazine and sunset yellow in soft drink sample, candy sample, and instant powder drink and leads to consistent results as obtained from the Chinese national standard method.

  6. Determination of tetracycline antibiotics in fatty food samples by selective pressurized liquid extraction coupled with high-performance liquid chromatography and tandem mass spectrometry.

    Science.gov (United States)

    Jiao, Zhe; Zhang, Suling; Chen, Hongwei

    2015-01-01

    For the determination of trace residues of tetracycline antibiotics in fatty food samples, selective pressurized liquid extraction coupled with high-performance liquid chromatography and tandem mass spectrometry was applied in this study. Copper(II) isonicotinate was first used as online cleanup adsorbent in the selective pressurized liquid extraction process. The adsorbent to sample ratio, extraction temperature, extraction time, and recycle times, etc. were optimized. The tetracyclines in food samples of pork, chicken meat, and clam meat were detected by liquid chromatography with tandem mass spectrometry. Tetracycline was found at levels of 0.32 and 0.53 μg/g and oxytetracycline was found at 0.14 and 0.21 μg/g in chicken meat and clam meat, respectively, while chlorotetracycline and deoxytetracycline were below the detection limit. The detection limit (S/N = 3) for these four tetracyclines were from 0.2 to 3.3 ng/g, the recoveries were from 75.8 to 110.5%, and relative standard deviations were from 5.5 to 13.6%. Copper(II) isonicotinate showed a higher purification capacity than other cleanup adsorbents for extraction of antibiotics in fatty food and the recovery showed predominance compared with a pressurized liquid extraction method without adsorbent. The study demonstrated that copper(II) isonicotinate would be a promising cleanup adsorbent in pressurized liquid extraction for the analysis of trace organic pollutants in complicated samples. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Fundamental and practical studies on high-performance liquid affinity chromatography of biopolymers with novel stationary phases

    Energy Technology Data Exchange (ETDEWEB)

    Bacolod, M.D.

    1992-01-01

    Rigid microparticulate stationary phases having surface-bound metal chelating functions were developed and evaluated in high performance metal chelate affinity chromatography of proteins. Silica- and polystyrene-divinylbenzene-based metal chelate sorbents were produced in wide pore and in non-porous type of column packings. A major effort has been placed on development of non-porous highly crosslinked polystyrene-divinylbenzene (PSDVB). These PSDVB microparticles were produced by a two-step swelling polymerization, and exhibited excellent mechanical strength over a wide range of flow-rates and composition used in high performance liquid chromatography (HPLC). Simple and reproducible hydrophilic coatings were developed for the surface modification of hydrophobic PSDVB supports. A tetradentate metal chelating ligand, ethylenediamine-N, N[prime]-diacetic acid (EDDA), was covalently bound to the surface of the various supports. Sorbents having iminodiacetic acid (IDA) metal chelating functions were also evaluated. The hydrophilic character and surface coverage of various stationary phases were assessed chromatographically. Studies concerning the effects of eluent pH as well as the nature and concentration of salts on retention and selectivity with different metal chelate stationary phases having various immobilized metal ions were carried out. Elution schemes were developed for rapid separation of proteins in metal chelate affinity chromatography. EDDA stationary phases in metal forms can be viewed as complementary to IDA stationary phases since they afforded different selectivity and retentivity toward proteins. Hydrophilic PSDVB could be functionalized with IDA or EDDA metal chelating ligands or lectins. The non-porous metal chelate stationary phases afforded rapid separation of proteins by the development of multiple gradient systems, which permitted higher column peak capacity, enabling the separation of a greater number of proteins in a single chromatographic run.

  8. Quantitative and pattern recognition analysis of five marker compounds in Raphani semen using high-performance liquid chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Yeon Woo; Lee, Joo Sang; Zhao, Bing Tian; Woo, Mi Hee; Min, Byung Sun [College of Pharmacy, Drug Research and Development Center, Catholic University of Daegu, Gyeongsan (Korea, Republic of); Kim, Jeong Ah [College of Pharmacy, Research Institute of Pharmaceutical Sciences, Kyungpook National University, Daegu (Korea, Republic of); Eun, Rhan Woo [College of Pharmacy, Chosun University, Gwangju (Korea, Republic of)

    2015-09-15

    A rapid and simple high-performance liquid chromatography (HPLC)-photodiode array (PDA) analytical method was developed for the quantitative analysis of Raphani Semen (RS). This method was successfully used to determine the five main phenolic compounds found in RS specimens from different production regions. The compounds included sinapine thiocyanate (1), β-d-fructofuranosyl-α-d-(6-O-sinapoyl)-glucopyranoside (2), isorhamnetin 3,4′-di-O-β-d-glucoside (3), β-d-(3-O-sinapoyl)-fructofuranosyl-α-d-(6-O-sinapoyl)-glucopyranoside (4), and β-d-(3,4-O-disinapoyl)-fructofuranosyl-α-d-(6-O-sinapoyl)-glucopyranoside (5). The marker compounds were separated using an Agilent Eclipse XDB-C18 column (5.0 µm, 150 × 4.6 mm i.d.) by gradient elution with acetonitrile/water/0.1% trifluoroacetic acid (TFA) as the mobile phase (flow rate, 1.0 mL/min). This method was fully validated with respect to linearity, precision, accuracy, stability, and robustness. The HPLC analytical method was validated to conduct a pattern recognition analysis by repeatedly analyzing 56 seed samples including 55 RS (C01–C49 and K50–K55) and 1 Brassicae Semen samples. In addition, a content standard for RS was proposed. Compounds 1 and 4 were revealed as major components in the HPLC chromatogram, and their contents ranged from 0.06 to 0.20 and 0.02 to 0.35 mg/g, respectively. These results demonstrate the successful development of an analytical method suitable for evaluating the quality and distinguishing the origin of RS. In addition, we briefly describe the crucial liquid chromatography-tandem mass spectrometry (LC-MS/MS) analytical conditions for the precise simultaneous quantification of the marker compounds.

  9. Residue level and dissipation pattern of lepimectin in shallots using high-performance liquid chromatography coupled with photodiode array detection.

    Science.gov (United States)

    Kim, Sung-Woo; Rahman, Md Musfiqur; Abd El-Aty, A M; Truong, Lieu T B; Choi, Jeong-Heui; Park, Joon-Seong; Kim, Mi-Ra; Shin, Ho-Chul; Shim, Jae-Han

    2016-11-01

    Lepimectin, as an emulsifiable concentrate, was sprayed on shallots at the recommended dose rate (10 mL/20 L) to determine its residue levels, dissipation pattern, pre-harvest residue limits (PHRLs), and health risk. Samples were randomly collected over 10 days, extracted with acetonitrile, purified using an amino solid-phase extraction (NH2 -SPE) cartridge and analyzed using a high-performance liquid chromatography-photodiode array detection method. Field-incurred samples were confirmed using ultra-performance liquid chromatography-tandem mass spectrometry. The linearity was excellent, with a determination coefficient (R(2) ) of ≥0.9991. The recoveries at two spiking levels (0.2 and 1.0 mg/kg) ranged from 84.49 to 87.64% with relative standard deviations of ≤7.04%. The developed method was applied to field samples grown in separate greenhouses, one located in Naju and one in Muan, in the Republic of Korea. The dissipation pattern was described by first-order kinetics with half-lives of 1.9 (Naju) and 1.7 days (Muan). The PHRL curves indicated that, if the lepimectin residues are <0.18 (Naju) and <0.13 mg/kg (Muan) 5 days before harvest, the residue levels will be lower than the maximum residue limit (0.05 mg/kg) upon harvesting. The risk assessment data indicated that lepimectin is safe for use in the cultivation of shallots, with no risk of detrimental effects to the consumer. Copyright © 2016 John Wiley & Sons, Ltd.

  10. Global analysis of chemical constituents in Shengmai injection using high performance liquid chromatography coupled with tandem mass spectrometry.

    Science.gov (United States)

    Li, Fei; Cheng, Tao-fang; Dong, Xin; Li, Ping; Yang, Hua

    2016-01-05

    This study aimed to develop a specific and reliable method to comprehensively analyze the chemical constituents in Shengmai injection (SMI) using high performance liquid chromatography coupled with tandem mass spectrometry. The qualitative analysis of SMI was achieved on a Kromasil 100-5C18 column, and the results demonstrated that a total of sixty-two compounds in SMI were unambiguously assigned or tentatively identified, and further, twenty-one compounds including fourteen saponins, six lignans and one L-borneol-7-O-[β-D-apiofuranosyl (1→6)]-β-D-gluco-pyranoside were quantified by HPLC-MS. Furthermore, L-borneol-7-O-[β-D-apio-furanosyl (1→6)]-β-D-glucopyranoside, originated from Radix ophiopogonis, was identified and quantified in SMI for the first time. The method validation results indicated that the methods were simple, specific and reliable. All the investigated compounds showed good linearity (r(2)≥0.9992) with a relatively wide concentration range and acceptable recovery at 90.13-109.09%. Consequently, the developed methods were successfully applied to ten batches of SMI samples analysis. The proposed methods may provide a useful and comprehensive reference for the quality control of SMI, and thus to provide supporting data for the quality control and application of SMI clinically. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. Cobalamin speciation using reversed-phase micro-high-performance liquid chromatography interfaced to inductively coupled plasma mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Yanes, Enrique G. E-mail: yanes@bhnrc.usda.gov; Miller-Ihli, Nancy J. E-mail: miller-ihli@bhnrc.usda.gov

    2004-06-18

    Micro-high-performance liquid chromatography interfaced to inductively coupled plasma mass spectrometry was optimized for the determination and separation of a mixture of cobalt containing species. Four cobalamin species (cyanocobalamin, hydroxocobalamin, methylcobalamin, and 5'-deoxyadenosylcobalamin) representing the various forms of vitamin B12 as well as the harmful corrinoid analogue cobinamide dicyanide were separated using reversed-phase microcapillary chromatography with columns containing C18 packing material with a 2-{mu}m particle size. Selection of organic solvents for the separation took into consideration compatibility with the inductively coupled plasma mass spectrometer being used for element specific detection. Optimized method conditions included use of a methanol gradient and make-up solution for the nebulizer. Some issues associated with dead volume were overcome by the extension of the gradient program. The total analysis time was 52 min. The column-to-column variability was evaluated and was found to be very reasonable (9% RSD on average), confirming that this method is rugged and that the technology should be easily transferred to other laboratories.

  12. Screening of extraction methods for glycoproteins from jellyfish ( Rhopilema esculentum) oral-arms by high performance liquid chromatography

    Science.gov (United States)

    Ren, Guoyan; Li, Bafang; Zhao, Xue; Zhuang, Yongliang; Yan, Mingyan; Hou, Hu; Zhang, Xiukun; Chen, Li

    2009-03-01

    In order to select an optimum extraction method for the target glycoprotein (TGP) from jellyfish ( Rhopilema esculentum) oral-arms, a high performance liquid chromatography (HPLC)-assay for the determination of the TGP was developed. Purified target glycoprotein was taken as a standard glycoprotein. The results showed that the calibration curves for peak area plotted against concentration for TGP were linear ( r = 0.9984, y = 4.5895 x+47.601) over concentrations ranging from 50 to 400 mgL-1. The mean extraction recovery was 97.84% (CV2.60%). The fractions containing TGP were isolated from jellyfish ( R. esculentum) oral-arms by four extraction methods: 1) water extraction (WE), 2) phosphate buffer solution (PBS) extraction (PE), 3) ultrasound-assisted water extraction (UA-WE), 4) ultrasound-assisted PBS extraction (UA-PE). The lyophilized extract was dissolved in Milli-Q water and analyzed directly on a short TSK-GEL G4000PWXL (7.8 mm×300 mm) column. Our results indicated that the UA-PE method was the optimum extraction method selected by HPLC.

  13. [Determination of bisphenol A and alkyl phenols in canned food with high performance liquid chromatography--fluorescence].

    Science.gov (United States)

    Xiao, Jing; Shao, Bing; Wu, Yong-Ning; Wang, Zhu-Tian; Hou, Wei

    2007-11-01

    To establish a comprehensive analytical high performance liquid chromatography fluorescence detection (HPLC-FL) in detecting bisphenol A (BPA), nonylphenol (NP) and octylphenol (OP) in canned food sold in Beijing markets. BPA, NP and OP was extracted with methanol and dichloroacetamide and concentrated. The samples were purified on an solid extraction cartridges. The HPLC system consisted of Waters XTerra MS C18 column, a mixture of methanol and water as mobile phase and fluorescence detector with the excitation and emission wavelength at 225 nm and 310 nm respectively. The method established had a linear relationship, showing the detection limit of BPA, OP and NP being 0.5, 0.1 and 0.1 microg/kg in canned vegetable and instant noodle and 1, 0.5 and 0.5 microg/kg in canned fish and meat can, respectively. The recoveries of BPA, NP and OP were 74.9%-95.1% , 76.3%-103.6% and 72.1%-109.2%. The precision was 4.98%-11.2% , 2.35%-8.88% and 5.61%-12.3%, respectively. The method is simple with high sensitivity and selectivity, suitable for the determination of NP, OP and BPA in canned food.

  14. Determination of benzimidazole residues and their metabolites in raw milk using high performance liquid chromatography-diode array detection

    Directory of Open Access Journals (Sweden)

    Marija Denžić Lugomer

    2017-01-01

    Full Text Available A new analytical method using high performance liquid chromatography-diode array detector (HPLC-DAD was developed for the analysis of 18 benzimidazoles and their metabolites in milk. Samples were extracted with acetonitrile and n-hexane and purified by polymer cation exchange (PCX solid phase extraction cartridges. LC separation was performed on Xbridge C18 with gradient elution using acetonitrile and ammonium acetate buffer. The DAD detection was set at 298, 312, 254 and 290 nm. The method was validated according to the criteria of Commission Decision 2002/657/EC. The following validation parameters were set: accuracy (expressed as recovery 31.7-137.6 %, limit of decision (CCα 6.0-120.6 μg kg-1, detection capability (CCβ 6.1-120.8 μg kg-1, limit of detection (LOD 1-4 μg kg-1, limit of quantification (LOQ 4-18 μg kg-1, precision as CV 7.0-22.5 %, withinlaboratory reproducibility expressed as CV 8.8-30.6 %. Finally, the developed method was applied to the analysis of collected milk samples. A total of 50 milk samples was analysed for benzimidazole residues. All obtained concentrations for all compounds were below the LOQ values.

  15. Determination of methylisothiazolinone and methylchloroisothiazolinone in cosmetic products by ultra high performance liquid chromatography with tandem mass spectrometry.

    Science.gov (United States)

    Wittenberg, James B; Canas, Benjamin J; Zhou, Wanlong; Wang, Perry G; Rua, Diego; Krynitsky, Alexander J

    2015-09-01

    Isothiazolinone biocides are broad-spectrum preservatives that are widely used in cosmetics, household, and industrial products. An increase in the number of cases of allergic contact dermatitis to isothiazolinone preservatives, namely, methylisothiazolinone and methylchloroisothiazolinone, have been recently noticed. The Food and Drug Administration relies on analytical methods to quantify levels of use of cosmetic ingredients and support enforcement action against products that are not in compliance with the law. In this study, an efficient ultra high performance liquid chromatography with tandem mass spectrometry method was developed and validated for the determination of methylisothiazolinone and methylchloroisothiazolinone in selected cosmetic products. The lower limit of quantitation was determined to be 0.1 μg/g for both preservatives. A survey of 24 cosmetic products was conducted and found concentrations of methylisothiazolinone and methylchloroisothiazolinone ranging from not quantified, or below the lower limit of quantitation, to 89.64 μg/g and not quantified to 10.31 μg/g, respectively. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Identification of phenolic acids and flavonoids in monofloral honey from Bangladesh by high performance liquid chromatography: determination of antioxidant capacity.

    Science.gov (United States)

    Moniruzzaman, Mohammed; Yung An, Chua; Rao, Pasupuleti Visweswara; Hawlader, Mohammad Nurul Islam; Azlan, Siti Amirah Binti Mohd; Sulaiman, Siti Amrah; Gan, Siew Hua

    2014-01-01

    The aim of the present study was to characterize the phenolic acids, flavonoids, and antioxidant properties of monofloral honey collected from five different districts in Bangladesh. A new high performance liquid chromatography (HPLC) equipped with a UV detector method was developed for the identification of the phenolic acids and flavonoids. A total of five different phenolic acids were identified, with the most abundant being caffeic acid, benzoic acid, gallic acid, followed by chlorogenic acid and trans-cinnamic acid. The flavonoids, kaempferol, and catechin were most abundant, followed by myricetin and naringenin. The mean moisture content, total sugar content, and color characteristics of the honey samples were 18.36 ± 0.95%, 67.40 ± 5.63 g/100 g, and 129.27 ± 34.66 mm Pfund, respectively. The mean total phenolic acids, total flavonoid content, and proline content were 199.20 ± 135.23, 46.73 ± 34.16, and 556.40 ± 376.86 mg/kg, respectively, while the mean FRAP values and DPPH radical scavenging activity were 327.30 ± 231.87 μM Fe (II)/100 g and 36.95 ± 20.53%, respectively. Among the different types of honey, kalijira exhibited the highest phenolics and antioxidant properties. Overall, our study confirms that all the investigated honey samples are good sources of phenolic acids and flavonoids with good antioxidant properties.

  17. Analysis of anabolic androgenic steroids as sulfate conjugates using high performance liquid chromatography coupled to tandem mass spectrometry.

    Science.gov (United States)

    Rzeppa, S; Heinrich, G; Hemmersbach, P

    2015-01-01

    Improvements in doping analysis can be effected by speeding up analysis time and extending the detection time. Therefore, direct detection of phase II conjugates of doping agents, especially anabolic androgenic steroids (AAS), is proposed. Besides direct detection of conjugates with glucuronic acid, the analysis of sulfate conjugates, which are usually not part of the routine doping control analysis, can be of high interest. Sulfate conjugates of methandienone and methyltestosterone metabolites have already been identified as long-term metabolites. This study presents the synthesis of sulfate conjugates of six commonly used AAS and their metabolites: trenbolone, nandrolone, boldenone, methenolone, mesterolone, and drostanolone. In the following these sulfate conjugates were used for development of a fast and easy analysis method based on sample preparation using solid phase extraction with a mixed-mode sorbent and detection by high performance liquid chromatography coupled to tandem mass spectrometry (HPLC-MS/MS). Validation demonstrated the suitability of the method with regard to the criteria given by the technical documents of the World Anti-Doping Agency (WADA). In addition, suitability has been proven by successful detection of the synthesized sulfate conjugates in excretion urines and routine doping control samples. Copyright © 2015 John Wiley & Sons, Ltd.

  18. Analysis of six benzodiazepines in vitreous humor by high-performance liquid chromatography-photodiode-array detection.

    Science.gov (United States)

    Cabarcos, P; Tabernero, M J; Álvarez, I; López, P; Fernández, P; Bermejo, A M

    2010-11-01

    The purpose of this study was to validate a high-performance liquid chromatography-photodiode-array detetion method for the determination of six benzodiazepines in vitreous humor. The sample preparation was carried out using solid-phase extraction with Oasis HLB cartridges and 10% acetic acid/MeOH as elution solvent. The vitreous humor is less affected by postmortem changes and is a very useful sample when blood or urine specimens are not available. Linear curves for bromazepam, alprazolam, lorazepam, lormetazepam, diazepam, and tetrazepam were obtained within the range 0.03-3 μg/mL, with coefficients of correlation lower than 0.999. The limit of detection was 3 ng/mL, and the lower limit of quantification was 30 ng/mL for each benzodiazepine. Intra- and interassay for precision and accuracy provided results less than 16.81% and 16.78%, respectively. Recoveries were higher than 68.51% in all cases. Finally, the method was applied to determine benzodiazepines in vitreous humor from intoxicated patients.

  19. Fast analysis of capsaicinoids in Naga Jolokia extracts (Capsicum chinense) by high-performance liquid chromatography using fused core columns.

    Science.gov (United States)

    Stipcovich, Tea; Barbero, Gerardo F; Ferreiro-González, Marta; Palma, Miguel; Barroso, Carmelo G

    2018-01-15

    A rapid high-performance liquid chromatography method with a C18 reverse-phase fused-core column has been developed for the determination and quantification of the main capsaicinoids (nornordihydrocapsaicin, nordihydrocapsaicin, capsaicin, dihydrocapsaicin, homocapsaicin and homodihydrocapsaicin) present in Naga Jolokia peppers. A fused-core Kinetex™ C18 column (50×2.1mm i.d.; 2.6μm) was used for the analysis. The chromatographic separation was obtained with a gradient method in which the mobile phase was water (0.1% acetic acid) as solvent A and acetonitrile (0.1% acetic acid) as solvent B. The separation of all compounds was achieved in less than 3min with a total analysis time (sample-to-sample) of 10min. The robustness of the method was evaluated. The method showed excellent repeatability and intermediate precision expressed as coefficient of variance of less than 2%. The developed method was employed for the quantification of the major capsaicinoids present in different peppers and commercial products containing chilli peppers. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

    Directory of Open Access Journals (Sweden)

    Piątkowska Marta

    2017-09-01

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

  1. Rapid screening of toxic salbutamol, ractopamine, and clenbuterol in pork sample by high-performance liquid chromatography—UV method

    Directory of Open Access Journals (Sweden)

    Kunping Yan

    2016-04-01

    Full Text Available A rapid and simple high-performance liquid chromatography–UV method was developed for the separation and quantification of salbutamol, ractopamine, and clenbuterol in pork. A mixture of acetonitrile–formic acid–ammonium acetate was used as the mobile phase to separate three β-agonists on a C18 column with gradient. The effects of the addition of formic acid and ammonium acetate to mobile phases on the separation of β-agonists were investigated. These additives can greatly improve the resolution and sensitivity. Under the optimized chromatographic condition, this separation does not need extra sample preparation. Complete baseline separation of three β-agonists was achieved in 0.99. Excellent method reproducibility was found by intra- and interday precisions with a relative standard deviation of < 3%. The detection limit (S/N = 3 was found to be <0.05 μg/L; this method can be used for routine screening of the β-agonist residues in foods of animal origin before being identified by confirmatory methods.

  2. Separation and detection of plasmalogen in marine invertebrates by high-performance liquid chromatography with evaporative light-scattering detection.

    Science.gov (United States)

    Yamashita, Shinji; Abe, Akihiro; Nakagawa, Kiyotaka; Kinoshita, Mikio; Miyazawa, Teruo

    2014-12-01

    We have developed a new method for determining ethanolamine plasmalogen contents in marine invertebrates. This quantification method involves derivatization of ethanolamine glycerophospholipid (EtnGpl) subclasses, alkenylacyl (plasmalogen), diacyl, and alkylacyl subclasses, by enzyme treatment and acetylation, followed by separation and detection by high-performance liquid chromatography (HPLC) with evaporative light-scattering detection (ELSD). This method enabled complete separation of the subclasses, and the limit of detection for plasmalogen was 200 ng (260 pmol). The peak area of plasmalogen by ELSD was unaffected by the degree of unsaturated fatty acids in EtnGpl, in contrast to ultraviolet (UV) detection. Thus, this method enables accurate determination of plasmalogen contents in various species containing marine products possessing abundant polyunsaturated fatty acids (PUFA). The method developed here was applied to marine invertebrates available in Japan. The examined marine invertebrates showed a wide range of plasmalogen contents ranging from 19 to 504 μmol/100 g wet wt. The plasmalogen levels in samples except those of class Cephalopoda and Crustacea were more than 60 mol% of EtnGpl.

  3. Determination of calcium dobesilate in human plasma using ion-pairing extraction and high-performance liquid chromatography.

    Science.gov (United States)

    Róna, K; Ary, K

    2001-05-05

    A rapid, simple reversed-phase high-performance liquid chromatographic method with ultraviolet absorbance detection has been developed for the determination of calcium dobesilate in human plasma. Sample processing is based on an ion-pairing extraction with tetra-n-butylammonium hydroxide as cationic pairing ion and dichloromethane. Separation of the investigated calcium dobesilate and 2,4-dihydroxybenzoic acid as internal standard was achieved on a Discovery RP-Amide C16 analytical column with 50 mM, pH 2.5, potassium dihydrogenphosphate buffer-acetonitrile (75:25, v/v) mobile phase. The wavelength was set at 305 nm. The limit of quantitation is 100 ng/ml and the calibration curve is linear up to 50 microg/ml. Within-day and between-day precision expressed as the relative standard deviation is about 10% and the accuracy of the determination did not deviate from 100% by more than +/-10%. The developed method was found to be suitable for application in human bioequivalence studies.

  4. Magnetic graphene dispersive solid phase extraction combining high performance liquid chromatography for determination of fluoroquinolones in foods.

    Science.gov (United States)

    He, Xin; Wang, Geng Nan; Yang, Kun; Liu, Hui Zhi; Wu, Xia Jun; Wang, Jian Ping

    2017-04-15

    In this study, a magnetic graphene-based dispersive solid phase extraction method was developed that was combined with high performance liquid chromatography to determine the residues of fluoroquinolone drugs in foods of animal origin. During the experiments, several parameters possible influencing the extraction performance were optimized (amount of magnetic graphene, sample pH, extraction time and elution solution). This extraction method showed high absorption capacities (>6800ng) and high enrichment factors (68-79-fold) for seven fluoroquinolones. Furthermore, this absorbent could be reused for at least 40 times. The limits of detection were in the range of 0.05-0.3ng/g, and the recoveries from the standards fortified blank samples (bovine milk, chicken muscle and egg) were in the range of 82.4-108.5%. Therefore, this method could be used as a simple and sensitive tool to determine the residues of fluoroquinolones in foods of animal origin. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. High performance liquid chromatographic separation of eight drugs collected in Chinese Pharmacopoeia 2010 on amylose ramification chiral stationary phase

    Directory of Open Access Journals (Sweden)

    Yan Wang

    2012-10-01

    Full Text Available The enantiomers separation of eight pharmaceutical racemates collected in Chinese Pharmacopoeia 2010 (Ch.P2010, including nitrendipine, felodipine, omeprazole, praziquantel, sulpiride, clenbuterol hydrochloride, verapamil hydrochloride and chlorphenamine maleate, was performed on chiral stationary phase of amylose ramification by high performance liquid chromatography (HPLC on Chiralpak AD-H column and Chiralpak AS-H column with the mobile phase consisted of isopropanol and n-hexane. The detection wavelength and the flow rate were set at 254 nm and 0.7 mL/min, respectively. The effects of proportion of organic additives, alcohol displacer and temperature on the separation were investigated. The results indicated that eight chiral drugs were separated on chiral stationary phase of amylase ramification in normal phase chromatographic system. The chromatographic retention and resolution of enantiomers were adjusted by factors, including the changes of the concentration of alcohol displacer in mobile phase, organic alkaline modifier and column temperature. It was shown that the resolution was improved with reducing concentration of alcohol displacer. When the concentration of organic alkaline modifier was 0.2%, the resolution and the peak shape were fairly good. Most racemates mentioned above had the best resolution at column temperature of 25 °C. The best temperature should be kept unchanged in the process of separation so as to obtain stable separation results.

  6. Normal-phase high-performance liquid chromatographic determination and identification of aldrin, dieldrin, and DDTs in eggs.

    Science.gov (United States)

    Furusawa, N

    2001-05-01

    A method for the routine monitoring of residual aldrin, dieldrin, pp'-DDT, op'-DDT, pp'-DDE, and pp'-DDD in eggs by high-performance liquid chromatography (HPLC) with a photo-diode array (PDA) detector is described. The lipids extracted from a whole egg are cleaned by a solid-phase extraction (SPE) ISOLUTE NH2 column with a diethyl ether-hexane (5:95, v/v) eluent. The HPLC separation is carried out using a normal-phase (LiChrosorb NH2) column, a heptane-hexane eluent (97:3, v/v), and a PDA detector. The average recoveries from fortified target compounds (0.1, 0.2, 0.3, and 0.4 microg/g, respectively) are > or = 83%, with standard deviations (SDs) between 2 and 5%. The interassay variabilities and their SDs are < or = 4.8% and < or =0.7%, with intra-assay variabilities of 2.1-3.3%. The limits of determination for these compounds range from 0.04 to 0.08 microg/g.

  7. [Chromatographic identification and analysis of dextromoramide in the plasma by the method of high performance liquid chromatography].

    Science.gov (United States)

    Misztal, G; Przyborowski, L; Jednacz, T

    1989-01-01

    Dextromoramide and pethidine were separated and identified by thin-layer chromatography on silica gel, using ammonia and methanol (1.5:100) as the mobile phase, after previous extraction with dicthyl ether or with a mixture of n-hexane and isoamyl alcohol (98.5:1.5) from blood alkalized to pH 10.3 Dextromoramide can be revealed on the chromatograms in the amount of 0.5 micrograms and pethidine in the amount of 1 micrograms using the Dragendorff reagent. Reversed-phase TLC proved less sensitive. High-performance liquid chromatography on the column of LiChrosorb RP-18 was applied to the determination of dextromoramide in blood after extraction with diethyl ether, using methanol--phosphate buffer pH 4.5 (95:5) as the mobile phase. The determination range was of 0.5-5.0 micrograms per 2 cm3 of blood plasma (1.26.10(-8)-1.26.10(-7) mole/dm3).

  8. Fluorescence detection of tramadol in healthy Chinese volunteers by high-performance liquid chromatography and bioequivalence assessment

    Directory of Open Access Journals (Sweden)

    Zhou X

    2015-02-01

    Full Text Available Xiao Zhou, Ji Liu Department of Anesthesia, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, People’s Republic of China Abstract: This study developed a revised high-performance liquid chromatography fluorescence method to determine plasma tramadol concentration, and thereby to examine the bioequivalence of two tramadol formulations among healthy male Chinese volunteers. The study used a double-blind, randomized, 2×2 crossover-design principle. Calculated pharmacokinetic parameters for both formulations were consistent with previous reports. According to the observation of vital signs and laboratory measurement, no subjects had any adverse reactions. The geometric mean ratios (90% confidence interval of the test drug/reference drug for tramadol were 100.2% (95.3%–103.4% for the area under the plasma concentration–time curve (AUC from time zero to the last measurable concentration, 99.6% (94.2%–102.7% for the AUC from administration to infinite time, and 100.8% (93.1%–106.4% for maximum concentration. For the 90% confidence intervals of the test/reference AUC ratio and maximum concentration ratio of tramadol, both were in the acceptance range for bioequivalence. According to the two preparations by pharmacokinetic parameter statistics, the half-life, mean residence time, and clearance values showed no significant statistical differences. Therefore, the conclusion of this study was that the two tramadol formulations (tablets and capsules were bioequivalent. Keywords: tramadol hydrochloride, in vitro release, pharmacokinetic, bioequivalence, fluorescence detector

  9. High-performance liquid chromatography and derivative spectrophotometry for simultaneous determination of pravastatin and fenofibrate in the dosage form.

    Science.gov (United States)

    Hefnawy, Mohamed M; Mohamed, Mostafa S; Abounassif, Mohammed A; Alanazi, Amer M; Mostafa, Gamal A E

    2014-12-01

    High performance liquid chromatography (HPLC) and second-order derivative spectrophotometry have been used for simultaneous determination of pravastatin (PS) and fenofibrate (FF) in pharmaceutical formulations. HPLC separation was performed on a phenyl HYPERSIL C18 column (125 mm × 4.6 mm i.d., 5 μm particle diameter) in the isocratic mode using a mobile phase acetonitrile/0.1 % diethyl amine (50:50, V/V, pH 4.5) pumped at a flow rate of 1.0 mL min-1. Measurement was made at 240 nm. Both drugs were well resolved on the stationary phase, with retention times of 2.15 and 5.79 min for PS and FF, respectively. Calibration curves were linear (R = 0.999 for PS and 0.996 for FF) in the concentration range of 5-50 and 20-200 µg mL-1 for PS and FF, respectively. Pravastatin and fenofibrate were quantitated in combined preparations also using the second-order derivative response at 237.6 and 295.1 nm for PS and FF, respectively. Calibration curves were linear, with the correlation coefficient R = 0.999 for pravastatin and fenofibrate, in the concentration range of 5-20 and 3-20 µg mL-1 for PS and FF, respectively. Both methods were fully validated and compared, the results confirmed that they were highly suitable for their intended purpose.

  10. Phytochemical Profile of Erythrina variegata by Using High-Performance Liquid Chromatography and Gas Chromatography-Mass Spectroscopy Analyses

    Directory of Open Access Journals (Sweden)

    Suriyavathana Muthukrishnan

    2016-08-01

    Full Text Available Natural products derived from plant sources have been utilized to treat patients with numerous diseases. The phytochemical constituents present in ethanolic leaf extract of Erythrina variegata (ELEV were identified by using high-performance liquid chromatography (HPLC and gas chromatography-mass spectroscopy (GC-MS analyses. Shade dried leaves were powdered and extracted with ethanol for analyses through HPLC to identify selected flavonoids and through GC-MS to identify other molecules. The HPLC analysis of ELEV showed the presence of gallic and caffeic acids as the major components at concentrations of 2.0 ppm and 0.1 ppm, respectively, as well as other components. GC-MS analysis revealed the presence of 3-eicosyne; 3,7,11,15-tetramethyl-2-hexadecen-1-ol; butanoic acid, 3-methyl-3,7-dimethyl-6-octenyl ester; phytol; 1,2-benzenedicarboxylic acid, diundecyl ester; 1-octanol, 2-butyl-; squalene; and 2H-pyran, 2-(7-heptadecynyloxy tetrahydro-derivative. Because pharmacopuncture is a new evolving natural mode that uses herbal extracts for treating patients with various ailments with minimum pain and maximum effect, the results of this study are particularly important and show that ELEV possesses a wide range of phytochemical constituents, as indicated above, as effective active principle molecules that can be used individually or in combination to treat patients with various diseases.

  11. [Determination of thyreostats in bovine urine using ultra-high performance liquid chromatography-tandem mass spectrometry].

    Science.gov (United States)

    Lech, Rodziewicz; Jolanta, MasŁOwiecka; Anna, Sadowska; Halina, Car

    2017-10-08

    Five thyreostats (TSs), namely tapazole, thiouracil, methylthiouracil, propylthiouracil, and phenylthiouracil, were determined in bovine urine using ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) in positive electrospray ionization mode. Extraction and clean-up were achieved using a ChemElut cartridge with tert -butyl methyl ether, without a derivatization step. Separation was achieved on an Acquity UPLC SS T3 column. The mobile phase was acetonitrile and water containing 0.2% (v/v) formic acid. The mass spectrometer was operated in multiple reaction monitoring mode. Urine samples were spiked with TS solution at levels corresponding to 5, 10, 15, and 20 μg/L. The accuracy (internal standard corrected) ranged from 92% to 107%, with a repeatability precision (relative standard deviation, RSD) less than 15% for all five analytes. The RSDs within-laboratory reproducibility was less than 26%. The decision limits (CCα) and detection capabilities (CCβ) were obtained from a calibration curve and were in the ranges of 3.1-6.1 μg/L and 4.0-7.4 μg/L, respectively. The CCα and CCβ values were below the recommended concentration, which was set at 10 μg/L. The results show that the described method is suitable for the direct detection of TSs in bovine urine. This method can also be used to determine TSs in porcine urine.

  12. High-performance liquid chromatographic determination of β-carotene content in four varieties of lotus stamens

    Directory of Open Access Journals (Sweden)

    Nithida Phonkot

    2010-08-01

    Full Text Available A high-performance liquid chromatography method was developed to determine -carotene content in lotus stamens.The stamens of four varieties of Nelumbo nucifera (Gaertn. and ten samples bought from traditional drug stores were determined.Validation of the method was carried out, the linearity of the -carotene concentrations range from 6.50-58.50 g.mL-1were 0.9997-0.9998. The repeatability and intermediate precision were 0.29 %CV (n=9 and 7.48 %CV (n=9, respectively; theaccuracy was 100.10 %w/w, the detection limit was 9.83 ng.mL-1 and the quantitation limit was 29.80 ng.mL-1. The -caroteneof the four varieties were 465.77-1150.80 mg% (n=3, and of the store samples were 4.70-41.73 mg% (n=3. The resultsdemonstrated that the contents varied according to the variety. The contents in the samples obtained from traditionaldrug stores were much lower that those dried in our laboratory, this might due to the source of the stamens, duration, andconditions of storages.

  13. A reliable high-performance liquid chromatography with ultraviolet detection for the determination of sulfonamides in honey.

    Science.gov (United States)

    Granja, Rodrigo H M M; Niño, Alfredo M Montes; Rabone, Fernanda; Salerno, Alessandro Gonzalez

    2008-04-14

    The sulfonamides are stable chemotherapeutics used against the bacterial disease affecting bees, known as American foulbrood (Bacillus larvae), so their residues could appear in the honey of treated bees. Their presence at a concentration above the limit value is a potential hazard to human health. Brazilian authorities have included in the National regulatory monitoring program, the control of the three most widely used sulfonamides in honey production, i.e., sulfathiazole, sulfamethazine and sulfadimethoxine. A method for the determination of residual sulfonamides in honey, using sulfapyridine as an internal standard has been developed, optimized and validated. Some changes were implemented on current available methodologies for the analysis of sulfonamides in honey in order to adopt such procedures to Brazilian honey samples. Sulfonamides were extracted from honey with dichloromethane after dissolution with 30% sodium chloride, and cleaned up with solid phase extraction on Florisil columns. The eluate was analyzed by high-performance liquid chromatography with ultraviolet detection. The limit of detection was determined at 3 microg kg(-1), 4 microg kg(-1) and 5 microg kg(-1) for sulfathiazole, sulfamethazine and sulfadimethoxine, respectively with average recoveries of 61.0% for sulfathiazole; 94.5% for sulfamethazine and 86.0% for sulfadimethoxine at the 100 microg kg(-1) level. As the final step of validation procedure, the analysts were submitted to a blind spiked sample prepared by the quality assurance officer which results were successfully obtained regarding recovery and deviations.

  14. Phytochemical Profile of Erythrina variegata by Using High-Performance Liquid Chromatography and Gas Chromatography-Mass Spectroscopy Analyses.

    Science.gov (United States)

    Muthukrishnan, Suriyavathana; Palanisamy, Subha; Subramanian, Senthilkumar; Selvaraj, Sumathi; Mari, Kavitha Rani; Kuppulingam, Ramalingam

    2016-08-01

    Natural products derived from plant sources have been utilized to treat patients with numerous diseases. The phytochemical constituents present in ethanolic leaf extract of Erythrina variegata (ELEV) were identified by using high-performance liquid chromatography (HPLC) and gas chromatography-mass spectroscopy (GC-MS) analyses. Shade dried leaves were powdered and extracted with ethanol for analyses through HPLC to identify selected flavonoids and through GC-MS to identify other molecules. The HPLC analysis of ELEV showed the presence of gallic and caffeic acids as the major components at concentrations of 2.0 ppm and 0.1 ppm, respectively, as well as other components. GC-MS analysis revealed the presence of 3-eicosyne; 3,7,11,15-tetramethyl-2-hexadecen-1-ol; butanoic acid, 3-methyl-3,7-dimethyl-6-octenyl ester; phytol; 1,2-benzenedicarboxylic acid, diundecyl ester; 1-octanol, 2-butyl-; squalene; and 2H-pyran, 2-(7-heptadecynyloxy) tetrahydro-derivative. Because pharmacopuncture is a new evolving natural mode that uses herbal extracts for treating patients with various ailments with minimum pain and maximum effect, the results of this study are particularly important and show that ELEV possesses a wide range of phytochemical constituents, as indicated above, as effective active principle molecules that can be used individually or in combination to treat patients with various diseases. Copyright © 2016. Published by Elsevier B.V.

  15. Determination of valnemulin in swine and bovine tissues by ultra-high performance liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Li, Hui; Wang, Yingyu; Li, Xiaowei; Fu, Qin; Shan, Yawen; Liu, Tianhe; Xia, Xi

    2016-03-01

    A sensitive and reliable method has been developed and validated for the determination of valnemulin in swine and bovine muscle, liver, and kidney using solid-phase extraction (SPE) and ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). The tissue samples were extracted with mixture solution of acetonitrile and 0.01mol/L hydrochloric acid, defatted by n-hexane, and further cleaned up using SPE cartridges with polymeric sorbent. Gradient UHPLC separation was performed using an Acquity BEH C18 column with water and acetonitrile as the mobile phase. Multiple reaction monitoring mode of two precursor-product ion transitions for valnemulin was used. Mean recoveries from fortified samples ranged from 93.4 to 104.3% with 3.3-10.7% relative standard deviation. The limit of detection and quantification was 0.2 and 1μg/kg for the analyte, respectively. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. [Application of denaturing high performance liquid chromatography for the detection of maternal DNA contamination during prenatal diagnosis].

    Science.gov (United States)

    Gao, Lijie; Long, Yanming; Zhang, Rong; Li, Shuang; Zhang, Fenghuan; He, Guoping

    2014-02-01

    To establish a high-quality method for detecting short tandem repeats(STR) using denaturing high performance liquid chromatography(DHPLC) in order to exclude maternal contamination and improve the accuracy of prenatal diagnosis. Two families were recruited. DNA was extracted from blood samples from the parents as well as amniotic fluid. Sixteen STR sites were amplified and analyzed based on the range of allele length reported by a STR database. Maternal DNA was mixed with DNA derived from amniotic fluid samples with the ratio 1:1, 1:4, 1:9, 1:19 and 1:99. vWA STR site was detected with DHPLC to confirm the sensitivity of detection. Sixteen STR sites were analyzed by DHPLC, for which at least 10 were found to be different between the mothers and fetuses. The detection rate, with maternal contamination excluded, was 66.7%. And the sensitivity of detection was 1-10%. Maternal contamination of amniotic fluid can be rapidly excluded with accuracy with DHPLC, which features a high sensitivity and good quality control, and can meet the European standards and provide a reliable quality control platform for prenatal diagnosis.

  17. [Determination of alpha-arbutin, beta-arbutin and niacinamide in cosmetics by high performance liquid chromatography].

    Science.gov (United States)

    Cheng, Peng; Chen, Meilan; Zhu, Yan

    2010-01-01

    A high performance liquid chromatography (HPLC) method for the determination of two optical isomers of arbutin (alpha-arbutin and beta-arbutin) and niacinamide in cosmetics was developed. The samples were extracted by the mixture of salt water and chloroform (2:1, v/v). The separation was performed on an ODS-BP column (200 mm x 4.6 mm, 5 microm, Elite) with methanol-water (10:90, v/v) as the mobile phase at a flow rate of 0.5 mL/min and 25 degrees C. The detection wavelength was set at 220 nm and the sample injection volume was 20 microL. There were good linear relationships between the mass concentration and the peak areas of alpha-arbutin, beta-arbutin and niacinamide in the ranges of 0.07-50, 0.06-50 and 0.05-50 mg/L, respectively. The relative standard deviations (RSDs, n = 7) of alpha-arbutin, beta-arbutin and niacinamide were 1.65%, 1.73% and 1.33%, respectively. The proposed method has been applied for the determination of alpha-arbutin, beta-arbutin and niacinamide in cosmetics with recoveries of 91.7%-109.6%. This method is rapid, simple and suitable for the detection of whitening ingredients in cosmetic.

  18. Comparison of UV spectrophotometry and high performance liquid chromatography methods for the determination of repaglinide in tablets.

    Science.gov (United States)

    Dhole, Seema M; Khedekar, Pramod B; Amnerkar, Nikhil D

    2012-07-01

    Repaglinide is a miglitinide class of antidiabetic drug used for the treatment of type 2 diabetes mellitus. A fast and reliable method for the determination of repaglinide was highly desirable to support formulation screening and quality control. UV spectrophotometric and reversed-phase high performance liquid chromatography (RP-HPLC) methods were developed for determination of repaglinide in the tablet dosage form. The UV spectrum recorded between 200 400 nm using methanol as solvent and the wavelength 241 nm was selected for the determination of repaglinide. RP-HPLC analysis was carried out using Agilent TC-C18 (2) column and mobile phase composed of methanol and water (80:20 v/v, pH adjusted to 3.5 with orthophosphoric acid) at a flow rate of 1.0 ml/min. Parameters such as linearity, precision, accuracy, recovery, specificity and ruggedness are studied as reported in the International Conference on Harmonization (ICH) guidelines. The developed methods illustrated excellent linearity (r(2) > 0.999) in the concentration range of 5-30 μg/ml and 5-50 μg/ml for UV spectrophotometric and HPLC methods, respectively. Precision (%R.S.D UV spectrophotometric method and 99.71-100.25% for HPLC method which shows accuracy of the methods. The developed methods were found to be reliable, simple, fast, accurate and successfully used for the quality control of repaglinide as a bulk drug and in pharmaceutical formulations.

  19. Molecularly Imprinted Polymers (MIP for Selective Solid Phase Extraction of Celecoxib in Urine Samples Followed by High Performance Liquid Chromatography

    Directory of Open Access Journals (Sweden)

    Saeedeh Ansari

    2017-09-01

    Full Text Available In this study, for the analysis of human urine samples, a novel method explained for the determination of celecoxib, a nonsteroidal anti-inflammatory drug (NSAID, using molecularly imprinted solid-phase extraction (MISPE coupled with high-performance liquid chromatography (HPLC. The synthesis of the MIP was performed by precipitation polymerization in methacrylic acid (MAA, ethylene glycol dimethacrylate (EGDMA, chloroform, 2,2′-azobisisobutyronitrile (AIBN and celecoxib as the functional monomer, cross-linker monomer, solvent, initiator and target drug, respectively. The celecoxib imprinted polymer was utilized as a specific sorbent for the solid phase extraction (SPE of celecoxib from samples. The molecularly imprinted polymer (MIP performance was compared with the synthesized non-molecularly imprinted polymer (NIP. Scanning electron microscopy (SEM, FT-IR spectroscopy, UV-VIS spectrophotometry and thermogravimetric analysis (TGA/DTG were used for characterizing the synthesized polymers. Moreover, the MISPE procedure parameters such as pH, eluent solvent flow rate, eluent volume and sorbent mass that probably influence the extraction process have been optimized to achieve the highest celecoxib extraction efficiency. The relative standard deviation (RSD %, recovery percent, limit of detection (LOD and limit of quantification (LOQ of this proposed method were 1.12%, 96%, 8 µg L-1 and 26.7 µg L-1, respectively. The proposed MISPE-HPLC-UV method can be used for the separation and enrichment of trace amounts of celecoxib in human urine and biological samples.

  20. High performance liquid chromatography hyphenated to inductively coupled plasma mass spectrometry for V and Ni quantification as tetrapyrroles

    Energy Technology Data Exchange (ETDEWEB)

    Duyck, Christiane Beatrice, E-mail: cbduyck@vm.uff.br [Pontificia Universidade Catolica do Rio de Janeiro (PUC-Rio), R. Marques de Sao Vicente, 225, Gavea, Rio de Janeiro, RJ, 22451-900 (Brazil); Universidade Federal Fluminense (UFF), Campus do Valonguinho, Outeiro de Sao Joao Batista, s/no, 24020-150, Niteroi, RJ (Brazil); Saint' Pierre, Tatiana Dillenburg; Miekeley, Norbert [Pontificia Universidade Catolica do Rio de Janeiro (PUC-Rio), R. Marques de Sao Vicente, 225, Gavea, Rio de Janeiro, RJ, 22451-900 (Brazil); Oliveira da Fonseca, Teresa Cristina; Szatmari, Peter [Centro de Pesquisas Leopoldo A. Miguez de Mello da Petrobras (CENPES), Av. Horacio Macedo, 950, Cidade Universitaria, Rio de Janeiro, RJ, 21941-915 (Brazil)

    2011-05-15

    A method was developed for the determination of V and Ni as tetrapyrroles by High Performance Liquid Chromatography hyphenated to Inductively Coupled Plasma Mass Spectrometry (HPLC-ICP-MS) using reversed phase and elution gradient. Chlorinated solvents and tetrahydrofuran were investigated as regard to separation time and ICP-MS detection efficiencies. The final elution gradient program started from pure methanol to a mixture of 20:80 (v/v) chloroform:methanol. External quantification of V and Ni with inorganic standards by flow injection ICP-MS, used online with HPLC, resulted in 95% of recoveries. The Limits of Detection for V during methanol elution and for Ni during the 20% chloroform gradient elution were evaluated by their minimum detectable concentrations, which were, respectively, 5 {mu}g L{sup -1} and 8 {mu}g L{sup -1}. The methodology was applied to polar and resin fractions separated from a Brazilian crude oil and a sediment extract from an oil-polluted area in the Guanabara Bay, Rio de Janeiro, Brazil. Vanadium as tetrapyrroles represented the totality of V content in the polar fraction, whereas Ni was in different polar forms in the resin and sediment extract.

  1. [Determination of avermectin, diclazuril, toltrazuril and metabolite residues in pork by high performance liquid chromatography-tandem mass spectrometry].

    Science.gov (United States)

    Gong, Xiaoming; Sun, Jun; Dong, Jing; Yu, Jinling; Wang, Hongtao

    2011-03-01

    A method for the determination of avermectin, ivermectin, doramectin, moxidectin, eprinomectin, diclazuril, toltrazuril and its two metabolite residues in pork was developed using QuEChERS method with high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The sample was extracted with acetonitrile and purified through QuEChERS method using ODS as the sorbent. The target compounds were separated on a Venusil ASB C18 column (150 mm x 2.1 mm, 3.0 microm) and detected by HPLC-MS/MS. The linear ranges were 0.005 - 0.2 mg/L and the correlation coefficients were all above 0.990. The average recoveries and the relative standard deviations ranged from 73.2% to 91.5% and from 12% to 17% at the spiked levels of 0.005, 0.01 and 0.02 mg/kg for the 9 analytes in pork matrix. This method is reliable, and suitable for the determination of the residues of avermectin and related compounds in pork.

  2. Development of an analytical method to quantify total isoflavones in phytotherapic capsules using high-performance liquid chromatography

    Directory of Open Access Journals (Sweden)

    Liliane C. C. Auwerter

    2012-10-01

    Full Text Available Isoflavones can be found in grains and leaves of soybean. Currently, these are sold in pharmacies as phytotherapic capsules. Isoflavones have been recommended by doctors, especially for women, due to their ability to relieve menopause symptoms, among other benefits. However, no method exists for the official control of isoflavone content in capsules sold in the Brazilian market. This study aims to develop an appropriate analytical method to determine the total isoflavone content (daidzin, glycitin, and genistin, and their respective aglycone forms in phytotherapic capsules purchased in pharmacies in Curitiba, Parana State, Brazil, using the technique of high-performance liquid chromatography with UV detection (UV-HPLC. The HPLC system consisted of a quaternary pump, an autosampler, and Waters reversed-phase C18 column (5 μm × 300 mm. Analyses were carried out at 40 °C, using a flow rate of 1.0 mL/min (acetonitrile and acetic acid 0.1%, and detection was performed at 254 nm. The method was validated as required by ANVISA and showed to be reliable for the following parameters: linearity (r² >0.99, selectivity (correlation between 0.99 and 1.00, precision (relative standard derivation <1.59%, accuracy (from 80% to 111.63% intraday and from 80% to 117.88% interday recovery, and robustness.

  3. DEVELOPMENT AND VALIDATION OF THE HIGH PERFORMANCE LIQUID CHROMATOGRAPHY METHOD FOR THE QUANTITATIVE DETERMINATION OF ERYTHROMYCIN IN DERMO-PREPARATIONS.

    Science.gov (United States)

    Hortolomei, Manuela; Ochiuz, Lacramioara; Popovici, Iuliana; Timofte, D; Petrescu, Diana Cezarina; Ghiciuc, Cristina Mihaela

    2015-01-01

    For the analysis of erythromycin (ER) in topical pharmaceutical forms we developed a high performance liquid chromatography dosage method (HPLC) greatly improved over the method formalized by the European Pharmacopoeia 5th ed. The work conditions for using a chromatography column with C18 stationary phase were established as follows: optimal column temperature, 45 degrees C; the mobile phase consisted of a mixture of 0.001 M disodium phosphate solution : acetonitrile in the ratio 20:80, volume of sample injected 20 μL, injection rate 1 mL/min and spectrum was recorded at λ = 200 nm. The method was validated by determining the following parameters: system precision, linearity, limit of detection (LOD), limit of quantification (LOQ) and accuracy. We determined linearity in the concentration range studied, 0.025 to 1.5 mg/mL. The equation of the regression line is: A = 53.7430 x C + 0.00203 with a regression coefficient of 0.9997. The method has LOQ = 0.0196 mg/mL and LOD = 0.005969. The accuracy of the method is appropriate, the ER recovery degree is in the range of 101.27 - 104.99%. The HPLC method with UV detection for the quantitative determination of ER is manageable, responsive, linear, precise and accurate and it can be used for the quantitative analysis of ER in topical pharmaceutical formulations. UV DETECTION.

  4. Development of an offline bidimensional high-performance liquid chromatography method for analysis of stereospecific triacylglycerols in cocoa butter equivalents.

    Science.gov (United States)

    Kadivar, Sheida; De Clercq, Nathalie; Nusantoro, Bangun Prajanto; Le, Thien Trung; Dewettinck, Koen

    2013-08-21

    Acyl migration is a serious problem in enzymatic modification of fats and oils, particularly in production of cocoa butter equivalent (CBE) through enzymatic acidolysis reaction, which leads to the formation of non-symmetrical triacylglycerols (TAGs) from symmetrical TAGs. Non-symmetrical TAGs may affect the physical properties of final products and are therefore often undesired. Consequently, an accurate method is needed to determine positional isomer TAGs during the production of CBE. A bidimentional high-performance liquid chromatography (HPLC) method with combination of non-aqueous reversed-phase HPLC and silver ion HPLC joining with an evaporative light scattering detector was successfully developed for the analysis of stereospecific TAGs. The best separation of positional isomer standards was obtained with a heptane/acetone mobile-phase gradient at 25 °C and 1 mL/min. The developed method was then used in multidimensional determination of the TAG positional isomers in fat and oil blends and successfully identified the TAGs and possible isomers in enzymatically acidolyzed CBE.

  5. Quantitative analysis of cytokinins in plants by high performance liquid chromatography: electronspray ionization ion trap mass spectrometry.

    Science.gov (United States)

    Chen, Weiqi; Gai, Ying; Liu, Shichang; Wang, Renxiao; Jiang, Xiangning

    2010-10-01

    The present paper introduces a highly sensitive and selective method for simultaneous quantification of 12 cytokinins (free form and their conjugates). The method includes a protocol of extraction with methanol/water/formic acid (15/4/1, v/v/v) to the micro-scale samples, pre-purification with solid phase extraction (SPE) cartridges of the extracts, separation with a high performance liquid chromatography (HPLC) and detection by an electrospray ionization ion trap mass spectrometry (ESI-Ion trap-MS) system in a consecutive ion monitoring (CRM) mode at the three stage fragmentation of mass spectrometry (MS(3) ). The lowest detection level of the cytokinins of the method reaches 0.1-2.0 pg with a very wide range of linear regression from 1-512 pg, at the coefficient factors of 0.98-0.99. The feasibility of this method has been proven in the application of the method to the analysis of the trace-amount contents of cytokinins in the micro-scale samples of various types of plant materials, such as aerial parts of rice and poplar leaves etc. 12 endogenous cytokinins had been identified and quantified in the plant tissues, with an acceptable relatively higher recovery rate from 40% to 70%. © 2010 Institute of Botany, Chinese Academy of Sciences.

  6. [Monolithic molecularly imprinted column-high performance liquid chromatography for enrichment and determination of trace cytokinins in plant samples].

    Science.gov (United States)

    Sun, Lin; Du, Fuyou; Ruan, Guihua; Huang, Yijia

    2013-04-01

    A method based on monolithic molecularly imprinted polymer enrichment combining with high performance liquid chromatography (mMIP-HPLC) detection was developed for the selective determination of trace cytokinins (CTKs) in plant samples. Monolithic molecularly imprinted polymer (mMIP) column was prepared in stainless steel tube by using kinetin as the template, methacrylic acid (MAA) as the functional monomer, ethylene glycol dimethacrylate (EGDMA) as the cross-linker, and toluene-dodecanol as the porogenic solvents. Compared with non-imprinted polymer (NIP) monolith, the prepared mMIP exhibited selective separation ability, good reproducibility and reusability, and high extraction efficiency in the separation and enrichment of the four CTKs. Under the optimized experimental conditions, mean recoveries were 91.9%, 80.0%, 87.5% and 50.2% for kinetin (K), kinetin glucoside (KR) , trans-zeatin (tZ) and meta-topolin (mT), respectively, with the corresponding RSDs less than 11.8%. The proposed mMIP-HPLC method was successfully applied in the separation and determination of the four cytokinins in different plant samples

  7. Determination of pesticides and metabolites in wine by high performance liquid chromatography and second-order calibration methods.

    Science.gov (United States)

    Braga, Jez Willian B; Bottoli, Carla B G; Jardim, Isabel C S F; Goicoechea, Héctor C; Olivieri, Alejandro C; Poppi, Ronei J

    2007-05-04

    The models parallel factor analysis (PARAFAC) and the recently introduced bilinear least squares (BLLS) were applied to develop second-order calibration methods to high performance liquid chromatography with diode array detection (HPLC-DAD) data, where overlap of interferences with the compounds of interest was observed, making the determination and resolution of the analytes possible. In this work, the simultaneous determination of five pesticides and two metabolites in wine samples by HPLC-DAD was performed, using the second-order advantage. The results of two chromatographic methods were compared, involving either isocratic or gradient elution. An appropriate preprocessing method was necessary to correct the effects of time shifts, baseline variations and background. BLLS presented results that were of the same quality as PARAFAC in five cases, but in two other situations only PARAFAC enabled analyte quantitation. Relative errors of prediction lower than 10% for all compounds were obtained, indicating that the methodology employing HLPC-DAD and second-order calibration can handle complex analytical systems.

  8. [Determination of four plant growth regulator residues in amphisarcas by high performance liquid chromatography-tandem mass spectrometry].

    Science.gov (United States)

    Mou, Yanli; Guo, Dehua; Ding, Zhuoping

    2013-10-01

    A high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method was developed for the determination of the plant growth regulator (PGR) (paclobutrazol, forchlorfenuron, isopentennyladenine and 6-benzylaminopurine) residues in amphisarcas. The sample was extracted with acetonitrile, then cleaned up by MCX solid phase extraction. The HPLC separation was performed on an Agilent XDB-C18 column with 5 mmol/L ammonium acetate solution and acetonitrile containing 0.1% (volume percentage) formic acid as the mobile phases in a gradient elution mode. The PGRs were determined by MS/MS in positive electrospray ionization mode, and quantified by matrix-matched external standard method. The calibration curves showed good linearity in each range with correlation coefficients greater than 0.999. The limits of quantification (LOQs, S/N > 10) were 0.04-1.35 g/kg and the limits of detection (LODs, S/N > 3) were 0. 01-0 41 microg/kg for the four PGRs spiked in cucumber and apple. The recoveries of the four PGRs spiked at three levels ranged from 81.0% to 93.%, with the relative standard deviations (RSDs) of 3.5%-9.5%. The sensitivity, accuracy and precision of the method meet the technical standards of the pesticide determination. Therefore the method can be applied to the determination of the four PGRs in amphisarcas.

  9. Characterization of Date (Deglet Nour) Seed Free and Bound Polyphenols by High-Performance Liquid Chromatography-Mass Spectrometry.

    Science.gov (United States)

    Sirisena, Sameera; Zabaras, Dimitrios; Ng, Ken; Ajlouni, Said

    2017-02-01

    Date (Pheonix dactylifera L.) seeds are a valuable and abundant by-product with various potential food applications. Free polyphenols (FPPs) and bound polyphenols (BPPs) of date seeds from Deglet Nour variety grown in Australia were investigated using high-performance liquid chromatography-mass spectrometry. The FPP fraction contained the following main phenolic compounds per gram of date seed powder; procyanidin B1 (499.8 ± 7.8 μg), procyanidin B2 (288.6 ± 6.1 μg), catechin (167.6 ± 2.1 μg), epicatechin (39.44 ± 0.39 μg), and protocatechuic acid (1.77 ± 0.22 μg). Additionally, one of the 2 A-type dimers was confirmed as procyanidin A2 (24.05 ± 0.12 μg/g). A-type dimers have not been reported before in date seeds. The BPP fraction contained epicatechin (52.59 ± 0.76 μg/g) and procyanidin B2 (294.2 ± 3.7 μg/g), while several peaks exhibiting ESI- m/z of 153 indicated dihydroxybenzoic acid isomers including protocatechuic acid (2.138 ± 0.025 μg/g). These findings contributed to our knowledge of date seed phytochemicals and understanding of their contribution to the reported bioactivities. © 2017 Institute of Food Technologists®.

  10. Simultaneous quantification of retinol, retinal, and retinoic acid isomers by high-performance liquid chromatography with a simple gradiation.

    Science.gov (United States)

    Miyagi, M; Yokoyama, H; Shiraishi, H; Matsumoto, M; Ishii, H

    2001-06-15

    A new method of high-performance liquid chromatography (HPLC) analysis to quantify isomers of retinol, retinal and retinoic acid simultaneously was established. The HPLC system consisted of a silica gel absorption column and a linear gradient with two kinds of solvents containing n-Hexane, 2-propanol, and glacial acetic acid in different ratios. It separated six retinoic acid isomers (13-cis, 9-cis, all-trans, all-trans-4-oxo, 9-cis-4-oxo, 13-cis-4-oxo), three retinal isomers (13-cis-, 9-cis-, and all-trans) and two retinol isomers (13-cis- and all-trans). Human serum samples were subjected to this HPLC analysis and at least, all-trans retinol, 13-cis retinol, and all-trans retinoic acid were detectable. This HPLC system is useful for evaluating retinoic acid formation from retinol via a two-step oxidation pathway. Moreover, it could be applied to monitoring the concentrations of various retinoids, including all-trans retinoic acid in human sera.

  11. Ion-pair ultra-high performance liquid chromatographic analysis of monoamines: peak-splitting at high flow rates.

    Science.gov (United States)

    Van Schoors, Jolien; Brouwer, Hendrik-Jan; Maes, Katrien; Michotte, Yvette; Van Eeckhaut, Ann

    2013-12-20

    The use of ion-pair ultra-high performance liquid chromatography (UHPLC) coupled with electrochemical detection (ECD) is of great interest for the fast and sensitive determination of the monoamine neurotransmitters dopamine, noradrenaline and serotonin in microdialysis samples. However, when applying high flow rates in ion-pair UHPLC, other peaks than the initial compound peaks appear on the chromatogram. This peak-splitting phenomenon is caused by disturbed ion-pair retention mechanisms. The influence of several chromatographic parameters is investigated. Peak-splitting is delayed to higher flow rates when increasing the concentration of ion-pair reagent or buffering agent in the mobile phase, when decreasing the percentage of organic modifier in the mobile phase, when applying a stationary phase with a smaller amount of packing material or when increasing the separation temperature. One or a combination of these conditions can be applied to analyze the monoamine neurotransmitters using ion-pair UHPLC-ECD at high flow rates. Copyright © 2013 Elsevier B.V. All rights reserved.

  12. Rapid Isolation and Determination of Flavones in Biological Samples Using Zinc Complexation Coupled with High-Performance Liquid Chromatography

    Directory of Open Access Journals (Sweden)

    Chenghe Sun

    2016-08-01

    Full Text Available Chlorophyll-type contaminants are commonly encountered in the isolation and determination of flavones of plant aerial plant parts. Heme is also a difficult background substance in whole blood analysis. Both chlorophyll and heme are porphyrin type compounds. In this study, a rapid method for isolating flavones with 5-hydroxyl or ortho-hydroxyl groups from biological samples was developed based on the different solubilities of porphyrin-metal and flavone-metal complexes. It is important that other background substances, e.g., proteins and lipids, are also removed from flavones without an additional processing. The recoveries of scutellarin, baicalin, baicalein, wogonoside and wogonin, which are the primary constituents of Scutellaria baicalensis (skullcaps were 99.65% ± 1.02%, 98.98% ± 0.73%, 99.65% ± 0.03%, 97.59% ± 0.09% and 95.19% ± 0.47%, respectively. As a sample pretreatment procedure, this method was coupled to high-performance liquid chromatography (HPLC with good separation, sensitivity and linearity and was applied to determine the flavone content in different aerial parts of S. baicalensis and in dried blood spot samples.

  13. [Determination of amygdalin content in Semen Armeniacae Amarum by high-performance liquid chromatography with evaporative light-scattering detection].

    Science.gov (United States)

    Wu, Zhao-hui; You, Wen-wei; He, Feng

    2005-12-01

    High-performance liquid chromatography with evaporative light-scattering detection (HPLC-ELSD) was employed for determination of amygdalin content in Semen Armeniacae Amarum. The detection was performed with the column of Hypersil-ODS (4.6 mm x 250 mm, 5 microm) and column temperature of 25 degrees C. The mobile phase was methanol-water (70:30) with flow rate of 0.5 ml/min. Evaporative light-scattering detector was used and the drift tube temperature was set at 98 degrees Celsius with the gas flow rate of 3.2 L/min. A standard curve was generated, which was linear in the range of 1.0-15.1 microg for amygdalin content (r=0.999 9). The average recovery of amygdalin was 99.0% with RSD of 2.9% (n=5). Besides simplicity and rapidness, the method yields accurate and reproducible results and can therefore be used in the quality control of Semen Armeniacae Amarum.

  14. Monitoring gradient profile on-line in micro- and nano-high performance liquid chromatography using conductivity detection.

    Science.gov (United States)

    Zhang, Min; Chen, Apeng; Lu, Joann J; Cao, Chengxi; Liu, Shaorong

    2016-08-19

    In micro- or nano-flow high performance liquid chromatography (HPLC), flow-splitters and gradient elutions are commonly used for reverse phase HPLC separations. When a flow splitter was used at a high split-ratio (e.g., 1000:1 or higher), the actual gradient may deviate away from the programmed gradient. Sometimes, mobile phase concentrations can deviate by as much as 5%. In this work, we noticed that the conductivity (σ) of a gradient decreased with the increasing organic-solvent fraction (φ). Based on the relationship between σ and φ, a method was developed for monitoring gradient profile on-line to record any deviations in these HPLC systems. The conductivity could be measured by a traditional conductivity detector or a capacitively coupled contactless conductivity detector (C(4)D). The method was applied for assessing the performance of an electroosmotic pump (EOP) based nano-HPLC. We also observed that σ value of the gradient changed with system pressure; a=0.0175ΔP (R(2)=0.964), where a is the percentage of the conductivity increase and ΔP is the system pressure in bar. This effect was also investigated. Copyright © 2016. Published by Elsevier B.V.

  15. Amino acid profile of saliva from patients with oral squamous cell carcinoma using high performance liquid chromatography.

    Science.gov (United States)

    Reddy, Indira; Sherlin, Herald J; Ramani, Pratibha; Premkumar, Priya; Natesan, Anuja; Chandrasekar, Thiruvengadam

    2012-09-01

    Oral cancer is the leading cause of death worldwide and it is the eighth most common cause of cancer death. Cancer cells utilize more glucose and amino acids than their benign counterparts. Diagnosis of disease via the analysis of saliva is potentially valuable, as the collection of fluid is associated with fewer compliance problems than the collection of blood. Hence, the present study was undertaken to evaluate the comprehensive amino acid profiling of saliva by high performance liquid chromatography (HPLC). The study group comprised 16 subjects, of whom eight were classified as having well-differentiated oral squamous (OSCC) cell carcinoma (Group I) and eight were classified as having moderately differentiated oral squamous cell carcinoma (Group II). Eight healthy individuals comprised the control group (Group III). The results showed increased salivary levels of all the amino acids in both groups of OSCC patients (Groups I and II) when compared with healthy controls (Group III). Hence, our study showed higher levels of all amino acids in the saliva of OSCC patients than in the saliva of healthy controls. The increased levels may serve as a "diagnostic and prognostic marker" for oral squamous cell carcinoma and for further detection of metastatic spread.

  16. Genomic organization and polymorphisms detected by denaturing high-performance liquid chromatography of porcine SLC11A1 gene.

    Science.gov (United States)

    Wu, Zhen-Fang; Luo, Wen-Hua; Yang, Guan-Fu; Zhang, Xi-Quan

    2007-10-01

    SLC11A1 (also known as Natural Resistance Associated Macrophage Protein1, NRAMP1) plays a crucial role in resistance of inbred mice to infection with several intracellular pathogens such as Mycobacterium, Leishmania and Salmonella. In this study, PCR amplification and sequencing were performed to obtain the genomic organization and sequence of porcine SLC11A1 gene by comparative genomic analysis. Results showed that porcine SLC11A1 gene consists of 15 exons and 14 introns, which is consistent with that of mice and human. All introns were sequenced and their nucleotide sequences were submitted to GenBank. The exon/intron boundaries were determined by comparing cDNA sequence with amplified genomic DNA sequences. Mutational analysis was performed on exonic and neighboring intronic region by denaturing high-performance liquid chromatography (DHPLC) and sequencing confirmation. Forty polymorphisms were identified; six are located in exons and thirty-four in introns. Two exonic polymorphisms are nonsynonymous changes (D6H and V175I), three are synonymous changes (S23, G33 and I155), and one is in 3' UTR. The availability of the fine genomic organization and identification of the polymorphisms will facilitate the evaluation of porcine SLC11A1 functional role in diseases resistance or susceptibility.

  17. [Analysis of anthocyanin content in bilberry (Vaccinium myrtillus L.) fruit crude drugs by high-performance liquid chromatography method].

    Science.gov (United States)

    Burdulis, Deividas; Ivanauskas, Liudas; Jakstas, Valdas; Janulis, Valdimaras

    2007-01-01

    Bilberry (Vaccinium myrtillus L.) is rich in flavonoids (major part anthocyanins), tannins, phenolic and organic acids, and other biologically active compounds. Anthocianins possess a broad spectrum of therapeutic properties. Variation in anthocyanin content of bilberry fruit crude drugs is significant in optimizing collection conditions. Bilberry (Vaccinium myrtillus L.) crude drug samples were collected in July-September of 2006 in natural environment in the territory of Lithuania. Ultrasonic extraction was applied using methanol as solvent. Acidic hydrolysis was performed. Qualitative and quantitative composition of five major anthocyanidins (delphinidin, cyanidin, petunidin, peonidin, and malvidin) was estimated by high-performance liquid chromatography in frozen fruits. Cyanidin predominated in all crude drug samples. Dynamics of variation in qualitative and quantitative composition of anthocyanidins was estimated in bilberry fruits collected during vegetation period. The greatest total amount of all analyzed anthocyanidins was determined at the end of investigated period. Variation in qualitative and quantitative content of anthocyanidins in bilberry fruits collected in different regions of Lithuania was estimated as well. The greatest total amounts of anthocyanidins were found in samples collected in Krikstoniai forest (1.78%) and Prienai pinewood (2.13%) and the lowest amounts--in samples collected in Balkasodis forest (1.14%) and Ryliskes forest (0.99%). Significant variation in anthocyanidin content reaching 28.40% (delphinidin) was determined in bilberry fruits. It is important for the standardization of bilberry fruit crude drugs.

  18. Degradation and interconversion of plant pteridines during sample preparation and ultra-high performance liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Van Daele, Jeroen; Blancquaert, Dieter; Kiekens, Filip; Van Der Straeten, Dominique; Lambert, Willy E; Stove, Christophe P

    2016-03-01

    The degradation and interconversion of a selected set of pterins (dihydroneopterin, hydroxymethyldihydropterin, dihydroxanthopterin, neopterin, hydroxymethylpterin, xanthopterin, 6-formylpterin, 6-carboxypterin and pterin), spiked to charcoal-treated potato and Arabidopsis thaliana matrix was investigated, together with their relative recovery in potato and A. thaliana. As a result, a matrix-specific procedure for the ultra-high performance liquid chromatography-tandem mass spectrometry based determination of 6 aromatic pterins (neopterin, hydroxymethylpterin, xanthopterin, 6-formylpterin, 6-carboxypterin and pterin) is proposed: 1.5ml of an N2-flushed, alkaline (pH=10) extraction solvent is added to 200mg of plant sample. After boiling and homogenization, the samples are incubated: Arabidopsis samples for 30min at room temperature, while shaking, and potato samples for 2h at 37°C (applying a dienzyme treatment with α-amylase and protease). After a final boiling step, the samples are ultrafiltrated and resulting extracts are analyzed by UHPLC-MS/MS. Copyright © 2015 Elsevier Ltd. All rights reserved.

  19. Quantification of darunavir (TMC114) in human plasma by high-performance liquid chromatography with ultra-violet detection.

    Science.gov (United States)

    Goldwirt, Lauriane; Chhun, Stéphanie; Rey, Elisabeth; Launay, Odile; Viard, Jean-Paul; Pons, Gérard; Jullien, Vincent

    2007-10-01

    A precise and accurate high-performance liquid chromatography (HPLC) method with UV detection has been developed and validated for darunavir, a peptidic protease inhibitor. An internal standard, methylclonazepam, was added to 100 microL of plasma before a solid-phase extraction on C18 Bond Elut column. The eluted solutions were evaporated to dryness and reconstituted with 100 microL of mobile phase before being injected in the chromatographic system. The separation was performed on a C8 column using an acetonitrile and ultrapure water mixture (40:60, v/v) as mobile phase. All compounds were detected at a wavelength of 266 nm. The method was linear and validated over a concentration range of 0.25-20mg/L. The within-day precision, ranged from 3.0 to 7.9%, while the within-day accuracy ranged from -11.4 to 0.5%. The between day precision and accuracy were respectively less than 13.7 and -11.4%. The mean recovery was 75.7% for darunavir and 66.7% for methylclonazepam. This method provides a useful tool for therapeutic drug monitoring in HIV patients.

  20. An innovative, simple, fast, and less toxic high-performance liquid chromatographic method for determination of prednisone in capsules

    Directory of Open Access Journals (Sweden)

    Pedro Henrique Reis da Silva

    2017-06-01

    Full Text Available ABSTRACT Prednisone is an anti-inflammatory steroid drug widely used in clinical practice. However, no high-performance liquid chromatographic (HPLC method has been described in the literature for the determination of prednisone in capsules until now. Thus, an HPLC method was developed using a C18 (250x4.0, 5 µm column, with methanol:water (70:30 as mobile phase at a flow rate of 1 mL/min and detection at 240 nm. The developed method was validated following current Brazilian legislation. Additionally, linearity was assessed by evaluating the assumptions of normality, homoscedasticity, and independency of residuals, and the fit to the linear model. The method showed linearity (r2>0.99 over the range of 14.0-26.0 µg/mL, selectivity, precision (RSD<2.0%, robustness, and accuracy (average recovery of 100.05%. The chromatographic procedure was applied for assay and uniformity content determination of three different batches of prednisone capsules, showing to be suitable for their quality control.

  1. High-performance liquid chromatography and derivative spectrophotometry for simultaneous determination of pravastatin and fenofibrate in the dosage form

    Directory of Open Access Journals (Sweden)

    Hefnawy Mohamed M.

    2014-12-01

    Full Text Available High performance liquid chromatography (HPLC and second-order derivative spectrophotometry have been used for simultaneous determination of pravastatin (PS and fenofibrate (FF in pharmaceutical formulations. HPLC separation was performed on a phenyl HYPERSIL C18 column (125 mm × 4.6 mm i.d., 5 μm particle diameter in the isocratic mode using a mobile phase acetonitrile/0.1 % diethyl amine (50:50, V/V, pH 4.5 pumped at a flow rate of 1.0 mL min-1. Measurement was made at 240 nm. Both drugs were well resolved on the stationary phase, with retention times of 2.15 and 5.79 min for PS and FF, respectively. Calibration curves were linear (R = 0.999 for PS and 0.996 for FF in the concentration range of 5-50 and 20-200 µg mL-1 for PS and FF, respectively. Pravastatin and fenofibrate were quantitated in combined preparations also using the second-order derivative response at 237.6 and 295.1 nm for PS and FF, respectively. Calibration curves were linear, with the correlation coefficient R = 0.999 for pravastatin and fenofibrate, in the concentration range of 5-20 and 3-20 µg mL-1 for PS and FF, respectively. Both methods were fully validated and compared, the results confirmed that they were highly suitable for their intended purpose.

  2. High performance liquid chromatographic analysis and anticancer potential of Oplopanax horridus: Comparison of stem and berry extracts

    Science.gov (United States)

    Wang, Chong-Zhi; Aung, Han H.; Mehendale, Sangeeta R.; Shoyama, Yukihiro; Yuan, Chun-Su

    2009-01-01

    Oplopanax horridus or devil’s club is a herbal medicine distributed in North America. The constituents and pharmacological activities of O. horridus (OPH) are largely unknown. In this study, we assayed OPH stem and berry extracts using high performance liquid chromatography (HPLC). The anticancer potentials of extracts on different human cancer cell lines (SW-480, HCT-116, HT-29, MCF-7 and NSCLC) were determined by MTS method. The effect of stem extract on cancer cell cycle, expression of cyclin A, and apoptosis were assayed using flow cytometry. HPLC data showed that the composition of OPH stem extract is more complicated than the berry extract. The wavelength of maximum absorption of the major constituent in stem and berry is 196.0 nm and 201.9 nm, respectively. Compared to the berry extract, the stem extract showed significant potent antiproliferative effect on all the studied cell lines. The stem extract at 0.1 mg/ml arrested cancer cells in S- and G2/M-phases, and significantly induced expression of cyclin A. After treatment with 0.1 mg/ml of stem extract for 72 h, apoptotic cells were increased to 45.2%, while control was 9.6%. The cell cycle arrest and induction of apoptosis may play a critical role in cancer chemoprevention by Oplopanax horridus stem extract. PMID:19686820

  3. Quantitation of Pyrrole-Imidazole Polyamide in Rat Plasma by High-Performance Liquid Chromatography Coupled with UV Detection

    Directory of Open Access Journals (Sweden)

    Tomonori Kamei

    2012-01-01

    Full Text Available A simple and robust method using high-performance liquid chromatography with UV detection was developed and validated for the determination of six pyrrole-imidazole (PI polyamides (HN.49, TGF-β1f, TGF-β1t, HN.50f, HN.50t, and LOX-1 in rat plasma. After the plasma proteins were precipitated with methanol containing phenacetin as an internal standard, the analytes were separated on a Luna C18 (2 (5 μm, 4.6×150 mm. Calibration curves were linear over the range of 0.5 to 200 μg/mL for HN.49, 0.25 to 200 μg/mL for TGF-β1f, TGF-β1t, HN.50t, and LOX-1, 1 to 200 μg/mL for HN.50f in rat plasma. The inter- and intraday precision were below 15%, and the accuracy was within 15% at the quality controls. The validated method was successfully applied to sample analysis for the pharmacokinetic study.

  4. Graphene oxide: an adsorbent for the extraction and quantification of aflatoxins in peanuts by high-performance liquid chromatography.

    Science.gov (United States)

    Yu, Li; Li, Peiwu; Zhang, Qi; Zhang, Wen; Ding, Xiaoxia; Wang, Xiupin

    2013-11-29

    In this paper, graphene oxide (GO) was synthesized and specifically selected by centrifugation to extract four aflatoxins (B1, B2, G1, and G2) as an effective adsorbent. Then, the amount of aflatoxins was quantitatively measured by high-performance liquid chromatography (HPLC). The GO was characterized by X-ray diffraction (XRD), atomic force microscopy (AFM), and ultraviolet (UV) spectrophotometer. Several parameters that could affect the extraction efficiency, including the GO amount, methanol concentration in the extraction solvent, spiked amount, extraction time, and elution cycle, were also investigated and optimized in this work. Under optimal conditions, good linear relationships were achieved with the correlation coefficient (r) ranging from 0.99217 to 0.99995. The detection limit of this method for the four aflatoxins ranged from 0.08 to 0.65ng/g. Finally, the proposed method has been successfully applied to determine aflatoxins in peanut samples. The results show that the recoveries of the four aflatoxins range from 85.1% to 100.8% with the relative standard deviations between 2.1% and 7.9%. Copyright © 2013 Elsevier B.V. All rights reserved.

  5. Chromatographic fingerprinting analysis of Zhizhu Wan preparation by high-performance liquid chromatography coupled with photodiode array detector.

    Science.gov (United States)

    Sun, Hui; Chen, Xi; Zhang, Aihua; Sakurai, Tetsuro; Jiang, Jinzhong; Wang, Xijun

    2014-10-01

    Traditional Chinese medicine (TCM) formula has been used for over 1000 years and most of them contain complicate chemical constituents. Chromatographic fingerprinting has been widely accepted as a crucial method for qualitative and quantitative analyses for TCM. Zhi Zhu Wan (ZZW), a classical Chinese medical formula, has been commonly used for the treatment of gastrointestinal disease, which pose a serious challenge to its quality control. In this work, a sensitive and reliable method of high-performance liquid chromatography coupled with photodiode array detector (HPLC-PDA) was developed to control the quality of ZZW for chemical fingerprint analysis and quantitative analysis of four major bioactive constituents, including hesperidin, naringin, neohesperidin, and atractylenolide I. The chromatographic separation was performed on a Waters Symmetry C18 column (4.6 mm × 250 mm, 5 μm particle size), with an aqueous 0.095% phosphate acid and acetonitrile mobile phase gradient. Optimization of other experimental conditions was validated with satisfactory accuracy, precision, repeatability, and recovery. In quantitative analysis, the four components showed good regression (R > 0.9994) within test ranges, and the recovery method ranged from 99.32% to 100.630%. HPLC fingerprints of the ZZW samples were compared by performing similarity analysis. The results indicated that the newly developed HPLC-PDA fingerprint method would be suitable for quality control of ZZW.

  6. Determination of hexavalent chromium in traditional Chinese medicines by high-performance liquid chromatography with inductively coupled plasma mass spectrometry.

    Science.gov (United States)

    Li, Peng; Li, Li-Min; Xia, Jing; Cao, Shuai; Hu, Xin; Lian, Hong-Zhen; Ji, Shen

    2015-12-01

    An analytical method that combined high-performance liquid chromatography with inductively coupled plasma mass spectrometry has been developed for the determination of hexavalent chromium in traditional Chinese medicines. Hexavalent chromium was extracted using the alkaline solution. The parameters such as the concentration of alkaline and the extraction temperature have been optimized to minimize the interconversion between trivalent chromium and hexavalent chromium. The extracted hexavalent chromium was separated on a weak anion exchange column in isocratic mode, followed by inductively coupled plasma mass spectrometry determination. To obtain a better chromatographic resolution and sensitivity, 75 mM NH4 NO3 at pH 7 was selected as the mobile phase. The linearity of the proposed method was investigated in the range of 0.2-5.0 μg L(-1) (r(2) = 0.9999) for hexavalent chromium. The limits of detection and quantitation are 0.1 and 0.3 μg L(-1) , respectively. The developed method was successfully applied to the determination of hexavalent chromium in Chloriti lapis and Lumbricus with satisfactory recoveries of 95.8-112.8%. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. A Review on Recent Applications of High-Performance Liquid Chromatography in Metal Determination and Speciation Analysis.

    Science.gov (United States)

    Rekhi, Heena; Rani, Susheela; Sharma, Neha; Malik, Ashok Kumar

    2017-11-02

    High-performance liquid chromatography (HPLC) has several advantages over the conventional methods due to their operational simplicity. It is a vital tool to determine metal ions having same mass but different electronic configuration, to separate complex mixtures and to resolve ions that may be indistinguishable by mass spectrometry alone. Metal ions play vital role in many biological processes and involved in setting up of many diseases. Therefore, the development of simple methods for the detection and quantification of metals in real samples might serve as diagnostic tools for various diseases. This review article focuses on the recent main feature of this technique, i.e. speciation of metal ions and their applications to series of problem of metal ion chemistry in different environmental matrixes. Speciation of metals is of increasing interest and has a great importance because of bioavailability, environmental mobility, toxicity and potential risk of metals. With the capability of partitioning the complex species of different metal ions, HPLC is an efficient technique for this task. This review summarizes recent advances in the development of HPLC to the fundamental understanding of metal ion chemistry in the environment and discusses all the issues that still need a lot of consideration. It has been classified into different sections depending on the role of HPLC in separation used and metal speciation; furthermore, the underlying sample preconcentration techniques and detection systems involved for the determination of metal ions and their applications were discussed.

  8. High-performance liquid chromatography as a technique to determine protein adsorption onto hydrophilic/hydrophobic surfaces.

    Science.gov (United States)

    Huang, Tongtong; Anselme, Karine; Sarrailh, Segolene; Ponche, Arnaud

    2016-01-30

    The purpose of this study is to evaluate the potential of simple high performance liquid chromatography (HPLC) setup for quantification of adsorbed proteins on various type of plane substrates with limited area (hydrophobic (polydimethylsiloxane: PDMS) surfaces, kinetics of adsorption were determined and amounts of adsorbed bovine serum albumin, myoglobin and lysozyme were obtained: as expected for each protein, the amount adsorbed at the plateau on glass (between 0.15 μg/cm(2) and 0.4 μg/cm(2)) is lower than for hydrophobic PDMS surfaces (between 0.45 μg/cm(2) and 0.8 μg/cm(2)). These results were consistent with bicinchoninic acid protein determination. According to ICH guidelines, both Reversed Phase and Size Exclusion HPLC can be validated for quantification of adsorbed protein. However, we consider the size exclusion approach more interesting in this field because additional informations can be obtained for aggregative proteins. Indeed, monomer, dimer and oligomer of bovine serum albumin (BSA) were observed in the chromatogram. On increasing the temperature, we found a decrease of peak intensity of bovine serum albumin as well as the fraction of dimer and oligomer after contact with PDMS and glass surface. As the surface can act as a denaturation parameter, these informations can have a huge impact on the elucidation of the interfacial behavior of protein and in particular for aggregation processes in pharmaceutical applications. Copyright © 2015 Elsevier B.V. All rights reserved.

  9. New High-performance Liquid Chromatography-DAD Method for Analytical Determination of Arbutin and Hydroquinone in Rat Plasma.

    Science.gov (United States)

    Gallo, F R; Pagliuca, G; Multari, G; Panzini, G; D'amore, E; Altieri, I

    2015-01-01

    Natural substances present in herbal preparations should be carefully used because they can give toxic or therapeutic effects despite of their amount or the way of administration. The safety of products of vegetable origin must be assessed before commercialisation by monitoring the active ingredients and their metabolites. This study was therefore designed to identify and quantify arbutin and its metabolite hydroquinone, naturally present in Arctostaphylos uva-ursi (L.) Spreng plant in rat plasma, after an acute and subacute administration of aqueous arbutin solution in Wistar rats. For this purpose a reversed-phase high-performance liquid chromatography coupled with photodiode array detection was developed to assess the pharmacokinetic of arbutin and hydroquinone in plasma of female rats treated with aqueous arbutin solutions. The detection (arbutin: 0.0617 µg/ml and hydroquinone 0.0120 µg/ml) and quantification (arbutin: 0.2060 µg/ml and hydroquinone: 0.0400 µg/ml) limits were determined. At the arbutin concentration level of 10.7 µg/ml repeatability was 13.33% and its recovery 93.4±6.93%, while at the hydroquinone concentration level of 10.6 µg/ml repeatability was 11.66% and its recovery 92.9±7.75%. Furthermore the method was fully validated and the obtained data indicate that the new method provides good performances.

  10. Measurement of the Patulin toxicant using high performance liquid chromatography (HPLC in apple juices supplied in Khorramabad City, Iran

    Directory of Open Access Journals (Sweden)

    Elham Esmaeili Lashkarian

    2016-11-01

    Full Text Available Making use of low quality moldy and worm-eaten fruits for juice production causes various irritations in human body due to its hazardous compounds. Today, Patulin toxicant is one of the most important compounds to be investigated in juices, particularly in apple juices. This research aims to measure the amount of Patulin toxicant and identify the molding factors in apple juices supplied in Khorramabad shops. After preparing a list of shops supplying and selling h\\juices in Khorramabad, 64 apple juices packs were collected at random. The Patulin measurement was accomplished using high performance liquid chromatography (HPLC and the molding factors identification also was performed using macroscopic, microscopic and other necessary tests after the sample were cultured in standard method. Out of 64 sample investigated from presence of lack of mold perspective, 61 (95.3% lacked mold and 1 (1.6% had Aspergillus terreus mold and 2 (3.1% had Penicillium mold. The Patulin level measured in 31 samples (48% was negative and in 33 ones (52% was positive in range 5.102-26.484 μg.l-1. The data obtained from samples was evaluated well in comparison to external standards and the correlation coefficient of 0.99 was indicated. The results obtained from this research indicated that the mean Patulin measured in apple juices studied was less than the EU and Iranian standards.

  11. Determination of patulin in apple juice using magnetic solid-phase extraction coupled with high-performance liquid chromatography.

    Science.gov (United States)

    Yu, Youwei; Fan, Zhefeng

    2017-02-01

    An efficient magnetic sorbent consisting of benzofuran-2-carboxylic acid-loaded magnetic nanocomposite was successfully synthesised for pre-concentration of patulin from apple juice. The prepared magnetic nanocomposite was characterised by scanning electron microscopy, transmission electron microscopy and Fourier-transform infrared spectroscopy. Determination of enriched patulin was performed by high-performance liquid chromatography. The best adsorption conditions were 40 mg of sorbent, 50 ml of apple juice sample, pH 5, ambient temperature and 25 min; the elution conditions were 500 μl methanol, pH 5, ambient temperature, and 4 min. Under optimised conditions, pre-concentration factor was 100, linearity range was 1-400 μg l-1 of patulin, limit of detection was 0.15 μg l-1 and limit of quantification was 0.5 μg l-1. When samples were determined 20 times, the recovery was 93.9-102.6% and the relative standard deviation was below 5.3%. In terms of proposed procedure, the developed method was successfully applied for patulin detection in apple juice samples.

  12. Fitting adsorption isotherms to the distribution data determined using packed micro-columns for high-performance liquid chromatography.

    Science.gov (United States)

    Jandera, P; Bunceková, S; Mihlbachler, K; Guiochon, G; Backovská, V; Planeta, J

    2001-08-03

    Knowing the adsorption isotherms of the components of a mixture on the chromatographic system used to separate them is necessary for a better understanding of the separation process and for the optimization of the production rate and costs in preparative high-performance liquid chromatography (HPLC). Currently, adsorption isotherms are usually measured by frontal analysis, using conventional analytical columns. Unfortunately, this approach requires relatively large quantities of pure compounds, and hence is expensive, especially in the case of pure enantiomers. In this work, we investigated the possible use of packed micro-bore and capillary HPLC columns for the determination of adsorption isotherms of benzophenone, o-cresol and phenol in reversed-phase systems and of the enantiomers of mandelic acid on a Teicoplanin chiral stationary phase. We found a reasonable agreement between the isotherm coefficients of the model compounds determined on micro-columns and on conventional analytical columns packed with the same material. Both frontal analysis and perturbation techniques could be used for this determination. The consumption of pure compounds needed to determine the isotherms decreases proportionally to the second power of the decrease in the column inner diameter, i.e. 10 times for a micro-bore column (1 mm I.D.) and 100 times for capillary columns (0.32 mm I.D.) with respect to 3.3 mm I.D. conventional columns.

  13. Preconcentration of synthetic phenolic antioxidants by using magnetic zeolites derived with carboxylatocalix[4]arenes combined with high performance liquid chromatography.

    Science.gov (United States)

    Zhou, Shaoyan; Li, Zheng; Lv, Xueju; Hu, Bin; Jia, Qiong

    2015-09-07

    Here, we synthesized a novel organic-inorganic hybrid material combining carboxylatocalix[4]arenes and magnetic zeolites by covalent bonding. The complex was characterized by scanning electron microscopy, transmission electron microscopy, Fourier-transformed infrared spectroscopy, X-ray diffraction spectrometry, thermogravimetric analysis/differential thermal gravity analysis, and by using an X-ray photoelectron spectrometer and a vibrating sample magnetometer. The resulting magnetic composite was employed as a solid phase adsorbent to separate and preconcentrate synthetic phenolic antioxidants. Various interactions between the targets and the adsorbent contributed to the adsorption efficiency including hydrophobic interaction, hydrogen-bond interaction, and π-π complexation. The superparamagnetic participation in the process of synthesizing zeolites made the separation process of adsorbent from solutions convenient by an external magnetic field. Taking advantage of this property, this adsorbent could be recycled more than 30 times. The concentrations of the preconcentrated SPAs were determined directly by high-performance liquid chromatography. Various experimental parameters were optimized, according to which the method was evaluated. Finally, the prepared magnetic zeolite@carboxylatocalix[4]arene was successfully applied to identify synthetic phenolic antioxidants from juice and infant milk powder samples with high enrichment factors in the range of 41.9-92.5. The magnetic materials allowed rapid and simple preconcentration, implying their potential in the field of adsorption.

  14. Simultaneous determination of caffeine and some selected polyphenols in Wuyi Rock tea by high-performance liquid chromatography.

    Science.gov (United States)

    Zhao, Feng; Lin, He-Tong; Zhang, Shen; Lin, Yi-Fen; Yang, Jiang-Fan; Ye, Nai-Xing

    2014-04-02

    The primary taste and healthy benefits of tea are mainly attributed to tea polyphenols and caffeine. Due to very many kinds of flavonoid glycosides in tea and the lack of commercial standards of flavonoid glycosides, it is critical to develop a rapid and cheap method for determining flavonoid glycosides of tea. Contents of myricetin glycosides and quercetin glycosides in Wuyi Rock tea were determined by detecting contents of corresponding myricetin and quercetin. Optimizing hydrolysis conditions for hydrolyzing flavonoid glycosides to their corresponding flavonols including quercetin and myricetin in Wuyi Rock tea was a key technology for detecting contents of corresponding myricetin and quercetin. The results showed that hydrolysis at 2 mol/L HCl solution and at 90 °C for 1 h was an optimizing condition for hydrolyzing flavonoid glycosides to myricetin and quercetin in Wuyi Rock tea. Caffeine and seven kinds of polyphenols (GA, EGC, C, EGCG, EC, ECG, and CGA) in 20 samples of Wuyi Rock tea were simultaneously determined using a simple and fast reverse-phase high-performance liquid chromatography procedure coupled with photodiode array detector (RP-HPLC-PDAD). The results indicated that there were significant (P < 0.05) differences of ECG, CGA, ECG, and myricetin glycosides in 'Wuyi Rougui' and 'Wuyi Shuixian', which were credited with causing the difference in taste between these two cultivar of Wuyi Rock tea. The study may be useful for clarifying the cause of "cultivated varieties flavor" of Wuyi Rock tea.

  15. Graphene/polyvinylpyrrolidone/polyaniline nanocomposite-modified electrode for simultaneous determination of parabens by high performance liquid chromatography.

    Science.gov (United States)

    Kajornkavinkul, Suphunnee; Punrat, Eakkasit; Siangproh, Weena; Rodthongkum, Nadnudda; Praphairaksit, Narong; Chailapakul, Orawon

    2016-02-01

    A nanocomposite of graphene (G), polyvinylpyrrolidone (PVP) and polyaniline (PANI) modified onto screen-printed carbon electrode (SPCE) using an electrospraying technique was developed for simultaneous determination of five parabens in beverages and cosmetic products by high performance liquid chromatography. PVP and PANI were used as the dispersing agents of graphene, and also for the enhancement of electrochemical conductivity of the electrode. The electrochemical behavior of each paraben was investigated using the G/PVP/PANI nanocomposite-modified SPCE, compared to the unmodified SPCE. Using HPLC along with amperometric detection at a controlled potential of +1.2V vs Ag/AgCl, the chromatogram of five parabens obtained from the modified SPCE exhibits well defined peaks and higher current response than those of its unmodified counterpart. Under the optimal conditions, the calibration curves of five parabens similarly provide a linear range between 0.1 and 30 µg mL(-1) with the detection limits of 0.01 µg mL(-1) for methyl paraben (MP), ethyl paraben (EP) and propyl paraben (PP), 0.02 and 0.03 µg mL(-1) for isobutyl paraben (IBP) and butyl paraben (BP), respectively. Furthermore, this proposed method was applied for the simultaneous determination of five parabens in real samples including a soft drink and a cosmetic product with satisfactory results, yielding the recovery in the range of 90.4-105.0%. Copyright © 2015 Elsevier B.V. All rights reserved.

  16. Simultaneous determination of acetaminophen, guaifenesin, pseudoephedrine, pholcodine, and paraben preservatives in cough mixture by high-performance liquid chromatography.

    Science.gov (United States)

    Carnevale, L

    1983-02-01

    The separation and simultaneous determination, by high-performance liquid chromatography, of acetaminophen (I), guaifenesin (II), pseudoephedrine hydrochloride (III), and pholcodine (IV), together with a series of parabens (methyl to butyl, V-VIII) in a cough mixture, has been demonstrated using a chemically bonded octadecylsilane stationary phase with a mobile phase of methanol-water-acetic acid (45:55:2) containing the ion-pairing agent octanesulfonic acid. Retention volumes for the active ingredients were 3.8 ml, 5.4 ml, 9.4 ml, and 15.6 ml for compounds I-IV, respectively. Corrected retention volumes for the parabens [5.4 ml for methyl (V), 9.6 ml for ethyl (VI), 18.5 ml for propyl (VII), and 37.9 ml for butyl (VIII)] showed an exponential relationship with chain length of the esterifying alcohols. Excipients did not interfere with the estimation of any of the compounds, hence pretreatment of the sample was unnecessary. Average recoveries of the active ingredients and of the parabens from laboratory prepared samples were essentially 100% of theoretical with standard deviations of 1.7, 0.3, 1.5, 0.3, 0.3, 3.3, 0.7, and 2.7% for I-VIII, respectively.

  17. [Determination of aniline in whole blood by using solid-phase extraction and high performance liquid chromatography with fluorescence detector].

    Science.gov (United States)

    Chen, Xiaohong; Zhao, Yonggang; Jin, Micong

    2015-03-01

    To establish a method for the determination of trace aniline in whole blood by using solid-phase extraction and high performance liquid chromatography with fluorescence detector. After the whole blood was diluted by water, extracted by acetonitrile, cleaned and enriched by Cleanert NH2 solid-phase extraction (SPE) cartridge, separation was performed on a Kromasil C8 column(250 mm x 4. 6 mm i. d., 5 λm) with the mobile phase of water/acetonitrile (20/80, V/V). Detection was carried out by fluorescence detector at ex 225 nm and λem 335 nm. Calibration curve was linear in the range of 3. 0 - 200.0 µg/L with a correlation coefficient of 0. 9992, and the limit of quantitation(LOQ) was 3. 0 µg/L. The extraction recoveries were 87. 5% - 104. 4%, and the intra-day and inter-day RSDs were 3. 1% - 6. 6% and 6. 4% - 8. 6%, respectively. The developed method is simple, fast, little interference, good specificity for the satisfactory determination of trace aniline in whole blood.

  18. Comparison of raw and processed Radix Polygoni Multiflori (Heshouwu by high performance liquid chromatography and mass spectrometry

    Directory of Open Access Journals (Sweden)

    Liang Zhitao

    2010-08-01

    Full Text Available Abstract Background Radix Polygoni Multiflori is the dried root tuber of Polygonum multiflorum Thunb. (Fam. Polygonaceae. According to Chinese medicine theory, raw (R-RPM and processed (P-RPM Radix Polygoni Multiflori possess different properties. The present study investigates the differences in chemistry between raw and processed Radix Polygoni Multiflori. Methods Five pairs of R-RPM and P-RPM as well as 15 commercial decoction pieces were analyzed with high performance liquid chromatography (HPLC and mass spectrometry (MS. Results Two anthraquinones, namely emodin-8-O-(6'-O-malonyl-glucoside and physcion-8-O-(6'-O-malonyl-glucoside disappeared or decreased significantly and 2,3,5,4'-tetrahydroxystilbene-2-O-β-D-glucopyranoside, emodin-8-O-β-D-glucopyranoside and physcion-8-O-β-D-glucopyranoside decreased after the R-RPM samples being processed. On the other hand, the contents of emodin and physcion generally increased after processing. Conclusion The present study indicates that processing Radix Polygoni Multiflori may change the contents and types of chemicals in it. These changes are probably responsible for the various pharmacological effects of R-RPM and P-RPM as well as hepatotoxicity.

  19. Application of microscopy technique and high performance liquid chromatography for quality assessment of Polygonum multiflorum Thunb. (Heshouwu).

    Science.gov (United States)

    Liang, Li; Zhao, Zhongzhen; Kang, Tingguo

    2014-10-01

    The technique of microscopy has been applied for identification of Chinese materia medica (CMM) since decades. However, very few scientific publications report the combination of conventional microscopy and high performance liquid chromatography (HPLC) techniques for further application to quality assessment of CMM. The objective of this study is to analyze the quality of the dried root tuber of Polygonum multiflorum Thunb. (Heshouwu) and to establish the relationships between 2,3,5,4'-tetrahydroxystilbene-2-O-β-glucoside, combined anthraquinone (CAQ) and quantity of clusters of calcium oxalate. In this study, microscopy and HPLC techniques were applied to assess the quality of P. multiflorum Thunb., and SPSS software was used to establish the relationship between microscopic characteristics and chemical components. The results showed close and direct correlations between the quantity of clusters of calcium oxalate in P. multiflorum Thunb. and the contents of 2,3,5,4'-tetrahydroxystilbene-2-O-β-glucoside and CAQ. From these results, it can be deduced that Polygoni Multiflori Radix with a higher quantity of clusters of calcium oxalate should be of better quality. The established method can be helpful for evaluating the quality of CMM based upon the identification and quantitation of chemical and ergastic substance of cells.

  20. Analysis of phenolic compounds in commercial dried grape pomace by high-performance liquid chromatography electrospray ionization mass spectrometry.

    Science.gov (United States)

    Ramirez-Lopez, Lina M; DeWitt, Christina A M

    2014-09-01

    By-products obtained from winemaking processes still contain large amounts of phenolic compounds, especially phenolic acids, flavanols, flavonols, stilbenes, and flavonoids. Enzymatic hydrolysis was used for determination and characterization of phenolic acids, flavanols, flavonols, and stilbenes. Characterization of the flavonoids was achieved using acid hydrolysis with 0.1% hydrochloric acid. In addition, organic solvents as 50% methanol, 70% methanol, 50% acetone, 0.01% pectinase, and 100% petroleum ether were also evaluated. Reversed phase high-performance liquid chromatography (RP-HPLC) with diode array detector was used to identify phenolic compounds. Internal standard quantification was implemented using a five points of the UV-visible absorption data collected at the wavelength of maximum absorbance. A total of 16 phenolic compounds were determined. The content differed from 1.19 to 1124 mg kg(-1). Outcomes from HPLC study showed that gallic acid, (+) catechin hydrate, and (-) epicatechin gallate were the major phenolic compounds presented in the sample. Malvidin and pelargonidin 3-O-glucoside were the major anthocyanins monoglucosides.

  1. Phytochemical profile and nutraceutical potential of chia seeds (Salvia hispanica L.) by ultra high performance liquid chromatography.

    Science.gov (United States)

    Martínez-Cruz, Oliviert; Paredes-López, Octavio

    2014-06-13

    Chia seeds (Salvia hispanica) were analyzed for total phenolic compounds, antioxidant activity, and quantification of phenolic acids and isoflavones by ultra high performance liquid chromatography (UHPLC), in order to obtain a phenolic phytochemical profile. The total phenolic concentration was 1.8-fold higher than previous reports and the antioxidant activity using DPPH (2,2-diphenyl-1-picrylhydrazyl) radical assay showed 68.83% inhibition, which was higher than the values reported previously for chia and different plant foods. Additionally, a simple, reproducible and rapid UHPLC method was proposed for the analysis of phenolic acids and isoflavones in chia. The method demonstrated to perform well with regard to linearity, limits of detection and quantification, precision, accuracy, and sensitivity. The detection limits ranged from 0.05 to 0.4ng/mL and the recovery percentage from 23.62 to 162.48%. With this method the major compounds identified and quantified were: rosmarinic acid 0.92, protocatechuic ethyl ester 0.74, caffeic acid 0.02, gallic acid 0.01, and daidzin 0.006mg/g seed. In brief, this study demonstrates that chia could be considered a seed with high antioxidant capacity and novel isoflavone source that can be incorporated in human diet. Copyright © 2014 Elsevier B.V. All rights reserved.

  2. Chromatographic performance of synthetic polycrystalline diamond as a stationary phase in normal phase high performance liquid chromatography.

    Science.gov (United States)

    Peristyy, Anton; Paull, Brett; Nesterenko, Pavel N

    2015-04-24

    The chromatographic properties of high pressure high temperature synthesised diamond (HPHT) are investigated in normal phase mode of high performance liquid chromatography. Purified nonporous irregular shape particles of average particles size 1.2 μm and specific surface area 5.1 m(2) g(-1) were used for packing 100×4.6 mm ID or 50×4.6 mm ID stainless steel columns. The retention behaviour of several classes of compounds including alkyl benzenes, polyaromatic hydrocarbons (PAH), alkylphenylketones, phenols, aromatic acids and bases were studied using n-hexane-2-propanol mixtures as mobile phase. The results are compared with those observed for microdispersed sintered detonation nanodiamond (MSDN) and porous graphitic carbon (PGC). HPHT diamond revealed distinctive separation selectivity, which is orthogonal to that observed for porous graphitic carbon; while selectivities of HPHT diamond and microdispersed sintered detonation nanodiamonds are similar. Owing to non-porous particle nature, columns packed with high pressure high temperature diamond exhibited excellent mass transfer and produce separations with maximum column efficiency of 128,200 theoretical plates per meter. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. Prototyping of thermoplastic microfluidic chips and their application in high-performance liquid chromatography separations of small molecules.

    Science.gov (United States)

    Wouters, Sam; De Vos, Jelle; Dores-Sousa, José Luís; Wouters, Bert; Desmet, Gert; Eeltink, Sebastiaan

    2017-11-10

    The present paper discusses practical aspects of prototyping of microfluidic chips using cyclic olefin copolymer as substrate and the application in high-performance liquid chromatography. The developed chips feature a 60mm long straight separation channel with circular cross section (500μm i.d.) that was created using a micromilling robot. To irreversibly seal the top and bottom chip substrates, a solvent-vapor-assisted bonding approach was optimized, allowing to approximate the ideal circular channel geometry. Four different approaches to establish the micro-to-macro interface were pursued. The average burst pressure of the microfluidic chips in combination with an encasing holder was established at 38MPa and the maximum burst pressure was 47MPa, which is believed to be the highest ever report for these polymer-based microfluidic chips. Porous polymer monolithic frits were synthesized in-situ via UV-initiated polymerization and their locations were spatially controlled by the application of a photomask. Next, high-pressure slurry packing was performed to introduce 3μm silica reversed-phase particles as the stationary phase in the separation channel. Finally, the application of the chip technology is demonstrated for the separation of alkyl phenones in gradient mode yielding baseline peak widths of 6s by applying a steep gradient of 1.8min at a flow rate of 10μL/min. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Determination of phenolic compounds using high-performance liquid chromatography with Ce{sup 4+}-Tween 20 chemiluminescence detection

    Energy Technology Data Exchange (ETDEWEB)

    Cui Hua; Zhou Jian; Xu Feng; Lai Chunze; Wan Guohui

    2004-05-31

    A novel method for the simultaneous determination of phenolic compounds such as salicylic acid, resorcinol, phloroglucinol, p-hydroxybenzoic acid, 2,4-dihydroxybenzoic acid, and m-nitrophenol by high-performance liquid chromatography (HPLC) coupled with chemiluminescence (CL) detection was developed. The procedure was based on the chemiluminescent enhancement by phenolic compounds of the cerium(IV)-Tween 20 system in a sulfuric acid medium. The separation was carried out with an isocratic elution or with a gradient elution using a mixture of methanol and 1.5% acetic acid. For six phenolic compounds, the detection limits (3{sigma}) were in the range 1.40-5.02 ng/ml and the relative standard deviations (n=11) for the determination of 0.1 {mu}g/ml compounds were in the range 1.9-2.9%. The CL reaction was well compatible with the mobile phase of HPLC, no baseline drift often occurred in HPLC-CL detection was observed with a gradient elution. The method has been successfully applied to the determination of salicylic acid and resorcinol in Dermatitis Clear Tincture and p-hydroxybenzoic acid in apple juices.

  5. Quantification of triazine herbicides in soil by microwave-assisted extraction and high-performance liquid chromatography.

    Science.gov (United States)

    Shah, Jasmin; Rasul Jan, M; Ara, Behisht; Shehzad, Farhat-Un-Nisa

    2011-07-01

    A method for the determination of herbicides residues, triazine (atrazine, metribuzin, ametryn, and terbutryn), in soil samples with high-performance liquid chromatography (HPLC)-UV detection is described. The proposed method is based on microwave-assisted extraction (MAE) of soil samples for 4 min at 80% of 850-W magnetron outputs in the presence of mixture of solvents (methanol/acetonitrile/ethylacetate). Related important factors influencing the MAE efficiency, such as the solvent type and volume, irradiation energy, and time, were optimized in detail. Calibration curve ranges established using HPLC for metribuzin, atrazine, ametryn, and terbutryn are 1.0-19.0, 0.9-18.0, 0.6-11.0, and 0.7-11.0 µg mL( -1), respectively. The limits of detection of metribuzin, atrazine, ametryn, and terbutryn are 0.30, 0.24, 0.16, and 0.20 µg mL( -1) while limits of quantification are 1.0, 0.80, 0.50, and 0.60 µg mL( -1), respectively. A Plackett-Burman factorial design was used as a screening method in order to select the variables that influence MAE extraction. The recoveries of the method at three different spiked levels were assessed by analyzing real soil samples and were found to be in the range of 83.33 ± 0.12-96.33 ± 0.23 with good precision (<8%).

  6. Analysis of stereochemistry and biosynthesis of epicatechin in tea plants by chiral phase high performance liquid chromatography.

    Science.gov (United States)

    Qian, Yumei; Zhao, Xianqian; Zhao, Lei; Cui, Lilan; Liu, Li; Jiang, Xiaolan; Liu, Yajun; Gao, Liping; Xia, Tao

    2015-12-01

    Tea (Camellia sinensis) is rich in flavan-3-ols (catechins), especially epicatechin (EC), which is the predominant extension unit of polymeric proanthocyanidins (PAs). However, studies assessing EC's stereochemistry are scarce. Here, a high performance liquid chromatography column using amylose tris-(3, 5-dimethylphenylcarbamate) immobilized on silica-gel as chiral stationary phases (CSPs) was applied to explore its stereochemistry and biosynthetic pathway in tea plants. The results revealed (-)-epicatechin [(-)-EC] was the predominant di-hyroxy-non-galloylated-catechins, while (+)-epicatechin [(+)-EC] was not detected. Interestingly, (-)-EC was the only product obtained from cyanidin using the partially purified native C. sinensis anthocyanidin reductase (CsANR) in the presence of reduction nicotinamide adenine dinucleotide phosphate (NADPH); meanwhile, (+)-EC was the main product using recombinant CsANR in the same conditions. In addition, (-)-EC could be obtained from (+)-catechin [(+)-C] using recombinant CsANR, which displayed C3-epimerase activity in the presence of oxidation nicotinamide adenine dinucleotide phosphate (NADP(+)). But the partially purified native CsANR did not possess this function. Finally, (-)-EC could result from the de-gallate acid reaction of epicatechin gallate (ECG) catalyzed by a novel partially purified native galloylated catechins hydrolase (GCH) from tea leaves. In summary, (-)-EC is likely the product of native protein from the tea plants, and (+)-EC is only produced in a reaction catalyzed by recombinant CsANR in vitro. Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.

  7. [Determination of serum or plasma alpha-tocopherol by high performance liquid chromatography: optimization of operative models].

    Science.gov (United States)

    Jezequel-Cuer, M; Le Moël, G; Mounié, J; Peynet, J; Le Bizec, C; Vernet, M H; Artur, Y; Laschi-Loquerie, A; Troupel, S

    1995-01-01

    A previous multicentric study set up by the Société française de biologie clinique has emphasized the usefulness of a standardized procedure for the determination by high performance liquid chromatography of alpha-tocopherol in serum or plasma. In our study, we have tested every step of the different published procedures: internal standard adduct, lipoprotein denaturation and vitamin extraction. Reproducibility of results was improved by the use of tocol as an internal standard when compared to retinol or alpha-tocopherol acetates. Lipoprotein denaturation was more efficient with ethanol addition than with methanol and when the ethanol/water ratio was > or = 0.7. Use of n-hexane or n-heptane gave the same recovery of alpha-tocopherol. When organic solvent/water ratio was > or = 1, n-hexane enabled to efficiently extract, in a one-step procedure, the alpha-tocopherol from both normo and hyperlipidemic sera. Performances of the selected procedure were: detection limit: 0.5 microM--linear range: 750 microM--within run coefficient of variation: 2.03%--day to day: 4.76%. Finally, this pluricentric study allows us to propose an optimised procedure for the determination of alpha-tocopherol in serum or plasma.

  8. Separation and Quantification of Eight Antidiabetic Drugs on A High-Performance Liquid Chromatography: Its Application to Human Plasma Assay

    Science.gov (United States)

    Lakshmi, Karunanidhi S.; Rajesh, Tirumala

    2011-01-01

    An analytical method based on isocratic reverse phase high-performance liquid chromatography was developed and validated for the separation and quantification of eight antidiabetic drugs: rosiglitazone, pioglitazone, glipizide, gliclazide, repaglinide, nateglinide, glibenclamide, and glimepiride for their application in human plasma assay. Metformin is used as internal standard. Analysis was done on Onyx monolithic C18 column (100 × 4.6 mm, i.d., 5 μm) using a mixture of 0.05% formic acid in water and methanol in the ratio of 42 : 58 (v/v) fixed at a flow rate of 0.5 mL/min, and they were monitored at 234 nm. Separation was achieved in less than 20 min. The calibration curves were linear in the range of 50–2000 ng/mL. The method was validated for its recovery, intra- and interday precision, stability, specificity, and selectivity. Plasma samples were prepared using solid-phase extraction of analytes. Hence, the developed method was found to be suitable for the routine analysis of selected antidiabetic drugs in biological matrices. PMID:22389851

  9. Simultaneous determination of amiodarone and its metabolite desethylamiodarone by high-performance liquid chromatography with chemiluminescent detection

    Energy Technology Data Exchange (ETDEWEB)

    Perez-Ruiz, Tomas [Department of Analytical Chemistry, Faculty of Chemistry, University of Murcia, 30071 Murcia (Spain)], E-mail: tpr@um.es; Martinez-Lozano, Carmen; Garcia-Martinez, Maria Dolores [Department of Analytical Chemistry, Faculty of Chemistry, University of Murcia, 30071 Murcia (Spain)

    2008-08-08

    A novel method was developed for the determination of amiodarone and desethylamiodarone by high-performance liquid chromatography (HPLC) coupled with chemiluminescent (CL) detection. The procedure is based on the post-column photolysis of the analytes into photoproducts which are active in the tris(2,2'-bipyridyl)ruthenium(III) [Ru(bpy){sub 3}{sup 3+}] CL system. Ru(bpy){sub 3}{sup 3+} was on-line generated by photo-oxidation of the Ru(II) complex in the presence of peroxydisulfate. The separation was carried out on a Mediterranea C{sub 18} column with isocratic elution using a mixture of methanol and 0.017 mol L{sup -1} ammonium sulfate buffer of pH 6.8. Under the optimum conditions, analytical curves, based on standard solutions, were linear over the range 0.1-50 {mu}g mL{sup -1} for amiodarone and 0.5-25 {mu}g mL{sup -1} for desethylamiodarone. The detection limits of amiodarone and desethylamiodarone were 0.02 and 0.11 {mu}g mL{sup -1}, respectively. Intra- and inter-day precision values of 0.9% relative standard deviation (R.S.D.) (n = 10) and 1.6% R.S.D. (n = 15), respectively, were obtained. The method was applied successfully to the determination of these compounds in serum and pharmaceutical formulations.

  10. Use of reversed-phase high-performance liquid chromatographic analysis for the determination of provitamin A carotenes in tomatoes.

    Science.gov (United States)

    Zakaria, M; Simpson, K; Brown, P R; Krstulovic, A

    1979-08-01

    The usual methods for provitamin A evaluation of foods convert the total pigment amount, determined spectrophotometrically, into vitamin A units. Since the totally inactive lycopene is the major carotenoid in the tomato, such readings result in erroneously high provitamin A values. In view of the recent development of chemically bonded, reversed-phase, microparticulate packings and their use in high-performance liquid chromatography which combines highly accurate and reproducible resolution with the speed and ease of operation, a new method using such a system was developed to isolate carotenoid pigments from tomato samples. A 15-min column separation was thus achieved, dramatically decreasing the analysis time of the classical open column chromatographic procedures, which often result in unresolved and altered fractions due to long-term exposure to oxygen, light, solvents and sometimes adsorbent. beta-Carotene and lycopene were determined and quantitated in six tomato samples. beta-Carotene, 100% vitamin A-active, was expressed in International Units of vitamin A. The newly developed method gives a more reliable evaluation of the fruit potency in vitamin A than the methods of the Association of Official Analytical Chemists currently used for food composition tables.

  11. Simultaneous determination of EDTA, sorbic acid, and diclofenac sodium in pharmaceutical preparations using high-performance liquid chromatography.

    Science.gov (United States)

    Heydari, Rouhollah; Shamsipur, Mojtaba; Naleini, Nasim

    2013-06-01

    A simple high-performance liquid chromatographic method for simultaneous determination of ethylenediaminetetraacetic acid (EDTA), sorbic acid, and diclofenac sodium was developed and validated. Separation was achieved on a C(18) column (10 cm×4.6 mm) using gradient elution. The mobile phase consisted of acetonitrile-ammonium dihydrogen phosphate buffer solution (0.01 M, pH=2.5, containing 0.8% tetra-n-butyl ammonium hydroxide). The detector wavelength was set at 254 nm. Under these conditions, separation of three compounds was achieved in less than 10 min. The effect of two metal salts and metal concentration on peak area of EDTA was investigated. The pH effect on retention of EDTA and sorbic acid was studied. The method showed linearity for EDTA, sorbic acid, and diclofenac in the ranges of 2.5-100.0, 5.0-200.0, and 20.0-120.0 μg/mL, respectively. The within- and between-day relative standard deviations ranged from 0.52 to 1.94%, 0.50 to 1.34%, and 0.78 to 1.67% for EDTA, sorbic acid, and diclofenac, respectively. The recovery of EDTA, sorbic acid, and diclofenac from pharmaceutical preparation ranged from 96.0-102.0%, 99.7-101.5%, to 97.0-102.5%, respectively. To the best of our knowledge, this is the first report about simultaneous determination of EDTA, sorbic acid, and diclofenac.

  12. Determination of carbamate pesticides using micro-solid-phase extraction combined with high-performance liquid chromatography.

    Science.gov (United States)

    Basheer, Chanbasha; Alnedhary, Anass Ali; Rao, B S Madhava; Lee, Hian Kee

    2009-01-09

    We describe a simple and sensitive porous polypropylene membrane-protected micro-solid-phase extraction (mu-SPE) approach for the sample preparation and determination of carbamate pesticides in soil samples by high-performance liquid chromatography. The mu-SPE device consisted of C(18) sorbent held within a porous polypropylene envelope. In order to achieve optimum performance, several extraction parameters were optimized. Under the most favorable conditions, the extraction efficiency of the mu-SPE was very high, with detection limits in the range of 0.01-0.40 ng g(-1). This is more than two orders of magnitude lower than the limits obtained by the United States Environmental Protection Agency Methods 8321A and 8318. A linear relationship was obtained for each analyte in the range of 2 and 200 ng g(-1). The relative standard deviation for the analysis of aged soil samples spiked at 5 ng g(-1) was experiments was satisfactory (relative standard deviations ranged from 4 to 11%), indicating that the method is reliable for routine environmental analysis.

  13. Simultaneous determination of methamphetamine and its metabolite, amphetamine, in urine using a high performance liquid chromatography column-switching method.

    Science.gov (United States)

    Kumihashi, Mitsuru; Ameno, Kiyoshi; Shibayama, Takayuki; Suga, Keisuke; Miyauchi, Hiroshi; Jamal, Mostofa; Wang, Weihuan; Uekita, Ikuo; Ijiri, Iwao

    2007-01-01

    We describe here a simple, precise, and highly sensitive method for the simultaneous determination of methamphetamine (MA) and amphetamine (AM) in urine using a high performance liquid chromatography (HPLC) column-switching method. A PK-2A (Shodex) column was used for extraction and deproteinization, and a CAPCELL PAK SCX semi-micro, polymer-coated cation-exchange column was employed for separation. The urine sample was mixed with an equal volume of borate buffer (0.1M, pH 9.4), and then 100 microl of the mixture was injected into the HPLC column. The column was switched for 6 min, and then 10 min later detection was performed at 210 nm. Recovery yields of the MA and AM spiked in the urine were 93.0-100.4% with a coefficient of variation of less than 1%. The calibration curves of MA and AM were in the range of 0.1-10 microg/ml with good linearity (r(2)=0.999), with the limit of qualification being 0.005 microg/ml. This method of using HPLC with column-switching can be used for both qualification and quantification of MA and its metabolite, AM, in urine, especially in forensic cases.

  14. Determination of some aldehydes by using solid-phase microextraction and high-performance liquid chromatography with UV detection.

    Science.gov (United States)

    Kumar, Ashwini; Singh, Baldev; Malik, Ashok Kumar; Tiwary, Dhananjay K

    2007-01-01

    A new approach has been developed for the extraction and determination of aldehydes such as veratraldehyde, m-nitrobenzaldehyde, cinnamaldehyde, benzaldehyde, and p-chlorobenzaldehyde by using solid-phase microextraction (SPME) and high-performance liquid chromatography with UV detection (HPLC/UV). The method involves adsorption of the aldehydes on polydimethylsiloxane/divinylbenzene-coated fiber, followed by desorption in the desorption chamber of the SPME-HPLC interface, using acetonitrile-water (70 + 30) as the mobile phase; UV detection was at 254 nm. A good separation of 5 aldehydes was obtained on a C18 column. The detection limits of veratraldehyde, m-nitrobenzaldehyde, cinnamaldehyde, benzaldehyde, and p-chlorobenzaldehyde are 25, 41, 13, 12, and 11 pg/mL, respectively, which are about 100 times better than the detection limits for other SPME methods using gas chromatography. The proposed method was validated by determining benzaldehyde in bitter almonds and cinnamaldehyde in cinnamon bark. The recoveries of the 5 analytes were determined by analysis of spiked drinking water.

  15. Simultaneous high performance liquid chromatographic analysis of vitamins B1, B2 and B6 in royal jelly

    Directory of Open Access Journals (Sweden)

    Presoto Ana Elisa F

    2004-01-01

    Full Text Available Royal jelly is used as a food supplement, popularly known as rich in B vitamins. The present work has two objectives: firstly, to apply simultaneous quantitative determination by High Performance Liquid Chromatography of thiamin (vitamin B1, riboflavin (vitamin B2 and pyridoxine (vitamin B6 and secondly to compare the obtained data with the Dietary Reference Intake (DRI values. The values obtained showed no thiamin, a range from 20 to 171 ng g-1 of riboflavin and from 408 to 2 188 ng g-1 of pyridoxine in royal jelly. According to the Food and Nutrition Board (2000, the DRI of these vitamins varies from 0.2-1.4 mg for thiamin; 0.3-1.6 mg for riboflavin and 0.1-2.0 mg for pyridoxine, depending on age and sex. According to these recommendations, royal jelly is not a good source of vitamins B1, B2 or B6 as these vitamins appear only on order of ng g-1. The proposed method can be used in routine analysis for royal jelly, having the advantage of being simple, fast and reliable.

  16. Automated preconcentration and analysis of organic compounds by on-line hollow fiber liquid-phase microextraction-high performance liquid chromatography.

    Science.gov (United States)

    Esrafili, Ali; Yamini, Yadollah; Ghambarian, Mahnaz; Ebrahimpour, Behnam

    2012-11-02

    The present work describes the first automated instrument, based on on-line hollow fiber liquid-phase microextraction (HF-LPME)-high performance liquid chromatography (HPLC), for the preconcentration and determination of organic compounds in various matrices. Using an automated syringe pump for loading the supported liquid membrane and acceptor solvents, a platform lift for moving the sample vial, a sampling loop for on-line injection of the extract to HPLC, along with an electronic board with an AVR microcontroller for storage of data and instrument programs, a sample preparation-HPLC method was developed that allowed sample extraction and extract injection to be carried out completely automatically. Pyridine and pyridine derivatives were chosen for the development and for testing the applicability of the automated instrument. The limits of detection (3 times the S/N) ranged from 0.5 to 1.0 μgL(-1). Effective preconcentration of the analytes was also achieved (preconcentration factors of between 40 and 220). The main advantages of the method developed are minimum sample manipulation, full automation, suitable extraction time, low solvent consumption, and ease of use. The applicability of the on-line automated HF-LPME/HPLC-UV instrument was validated for quantitative extraction and determination of pyridines in cigarette smoke. Copyright © 2012 Elsevier B.V. All rights reserved.

  17. Determination of Sudan I-IV in candy using ionic liquid/anionic surfactant aqueous two-phase extraction coupled with high-performance liquid chromatography.

    Science.gov (United States)

    Yu, Wei; Liu, Zhongling; Li, Qiang; Zhang, Hanqi; Yu, Yong

    2015-04-15

    Ionic liquid/anionic surfactant aqueous two-phase system was developed and applied for the extraction of Sudan I-IV. High-performance liquid chromatography was applied to the determination of the analytes. The aqueous two-phase system (ATPS) was formed in the present of C4[MIM]BF4, sodium dodecyl benzene sulphonate and (NH4)2SO4. The parameters affecting the extraction efficiency, such as volume of ionic liquid, amount of sodium dodecyl benzene sulphonate, ionic strength, pH value of system, extraction time and temperature were investigated. The limits of detection for Sudan I, II, III and IV were 5.45, 4.66, 3.68, 4.20 μg kg(-1), respectively. When the present method was applied to the analysis of candy samples, the recoveries of the analytes ranged from 82.3% to 112.1% and relative standard deviations were lower than 7.41%. Copyright © 2014 Elsevier Ltd. All rights reserved.

  18. [Determination of melamine residue in plant origin protein powders using high performance liquid chromatography-diode array detection and high performance liquid chromatography-electrospray ionization tandem mass spectrometry].

    Science.gov (United States)

    Ding, Tao; Xu, Jinzhong; Li, Jianzhong; Shen, Chongyu; Wu, Bin; Chen, Huilan; Li, Shujuan

    2008-01-01

    A method for the determination of melamine residue in plant origin protein powders was developed using high performance liquid chromatography-diode array detection (HPLC-DAD) and HPLC-electrospray ionization tandem mass spectrometry (ESI-MS/MS). HPL-DAD was used in preliminary screening of the samples for melamine, and HPLC-MS/MS was used in the confirmatory of melamine. Trichloroacetic acid solution was used to precipitate proteins and to dissociate the target analyte from the sample matrix. The supernatant was cleaned up with strong cation exchange column for HPLC-MS/MS. The HPLC-DAD separation was carried out on a C18 column (250 mm x 4.6 mm, 5 microm) with 0.01 mol/L sodium n-heptanesulfate (pH adjusted to 4.5 with citric acid)-acetonitrile (90:10, v/v) as mobile phase at a flow rate of 1.0 mL/min, and detected at 240 nm. HPLC-MS/MS was performed in selected ion monitoring mode with trichloroacetic acid solution as ion pair reagent. The limits of detection were 10 mg/kg and 0.5 mg/kg for HPLC-DAD and HPLC-MS/MS, respectively. The mean recoveries were 76%-88% for HPLC-DAD and 72%-82% (matrix match calibration curve) for HPLC-MS/MS and the relative standard deviations were 3.4%-6.4% for both HPLC-DAD and HPLC-MS/MS.

  19. Enzyme-assisted extraction and ionic liquid-based dispersive liquid-liquid microextraction followed by high-performance liquid chromatography for determination of patulin in apple juice and method optimization using central composite design.

    Science.gov (United States)

    Mohammadi, Abdorreza; Tavakoli, Rouya; Kamankesh, Marzieh; Rashedi, Hamid; Attaran, Abdolmohammad; Delavar, Mostafa

    2013-12-04

    A simple and highly sensitive analytical methodology for isolation and determination of patulin in apple-juice samples, based on enzyme-assisted extraction (EAE) and ionic liquid-based dispersive liquid-liquid microextraction (IL-DLLME) was developed and optimized. Enzymes play essential roles in eliminating interference and increasing the extraction efficiency of patulin. Apple-juice samples were treated with pectinase and amylase. A mixture of 80 μL ionic liquid and 600 μL methanol (disperser solvent) was used for the IL-DLLME process. The sedimented phase was analyzed by high-performance liquid chromatography (HPLC). Experimental parameters controlling the performance of DLLME, were optimized using response surface methodology (RSM) based on central composite design (CCD). Under optimum conditions, the calibration curves showed high levels of linearity (R(2)>0.99) for patulin in the range of 1-200 ng g(-1). The relative standard deviation (RSD) for the seven analyses was 7.5%. The limits of detection (LOD) and limits of quantification (LOQ) were 0.15 ng g(-1) and 0.5 ng g(-1), respectively. The merit figures, compared with other methods, showed that new proposed method is an accurate, precise and reliable sample-pretreatment method that substantially reduces sample matrix interference and gives very good enrichment factors and detection limits for investigation trace amount of patulin in apple-juice samples. Copyright © 2013 Elsevier B.V. All rights reserved.

  20. Comparison of extraction methods for the analysis of natural dyes in historical textiles by high-performance liquid chromatography.

    Science.gov (United States)

    Valianou, Lemonia; Karapanagiotis, Ioannis; Chryssoulakis, Yannis

    2009-12-01

    Different methods for the extraction of Dactylopius coccus Costa, Rubia tinctorum L., Isatis tinctoria L., Reseda luteola L., Curcuma longa L. and Cotinus coggygria Scop. from wool fibres are investigated using high-performance liquid chromatography with diode array detector (HPLC-DAD). The efficiencies of five extraction methods which include the use of HCl (widely used extraction method), citric acid, oxalic acid, TFA and a combination of HCOOH and EDTA are compared on the basis of the (a) number, (b) relative quantities, measured as HPLC peak areas and (c) signal-to-noise ratios (S/N) of the compounds extracted from the wool substrates. Flavonoid glycosides and curcuminoids contained in R. luteola L. and C. longa L., respectively, according to liquid chromatography with mass spectrometry (LC-MS) identifications, are not detected after treating the fibres with HCl. All the other milder methods are successful in extracting these compounds. Experiments are performed using HPLC-DAD to compare the HPLC peak areas and the S/N of the following extracted compounds: indigotin, indirubin, curcumin, demethoxycurcumin, bisdemethoxycurcumin, fisetin, sulfuretin, luteolin, luteolin-7-O-glucoside, apigenin, carminic acid, alizarin, puruprin and rubiadin. It is shown that the TFA method provides overall the best results as it gives elevated extraction yields except for fisetin, luteolin, apigenin and luteolin-7-O-glucoside and highest S/N except for fisetin and luteolin-7-O-glucoside. It is noteworthy that treatment of the fibres with the typical HCl extraction method results overall in very low S/N. The TFA method is selected for further studies, as follows. First, it is applied on silk dyed samples and compared with the HCl method. The same relative differences of the TFA and HCl methods observed for the wool dyed samples are reported for the silk dyed samples too, except for rubiadin, luteolin and apigenin. Thus, in most cases, the nature of the substrate (wool or silk

  1. High-performance liquid chromatographic analysis of as-synthesised N,N'-dimethylformamide-stabilised gold nanoclusters product

    Science.gov (United States)

    Xie, Shunping; Paau, Man Chin; Zhang, Yan; Shuang, Shaomin; Chan, Wan; Choi, Martin M. F.

    2012-08-01

    Reverse-phase high-performance liquid chromatographic (RP-HPLC) separation and analysis of polydisperse water-soluble gold nanoclusters (AuNCs) stabilised with N,N'-dimethylformamide (DMF) were investigated. Under optimal elution gradient conditions, the separation of DMF-AuNCs was monitored by absorption and fluorescence spectroscopy. The UV-vis spectral characteristics of the separated DMF-AuNCs have been captured and they do not possess distinct surface plasmon resonance bands, indicating that all DMF-AuNCs are small AuNCs. The photoluminescence emission spectra of the separated DMF-AuNCs are in the blue-light region. Moreover, cationic DMF-AuNCs are for the first time identified by ion chromatography. Our proposed RP-HPLC methodology has been successfully applied to separate AuNCs of various Au atoms as well as DMF-stabilised ligands. Finally, the composition of the separated DMF-AuNCs was confirmed by matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry and electrospray ionisation mass spectrometry, proving that the as-synthesised DMF-AuNCs product consists of Au10+, Au10, Au11, Au12, Au13, and Au14 NCs stabilised with various numbers of DMF ligands.Reverse-phase high-performance liquid chromatographic (RP-HPLC) separation and analysis of polydisperse water-soluble gold nanoclusters (AuNCs) stabilised with N,N'-dimethylformamide (DMF) were investigated. Under optimal elution gradient conditions, the separation of DMF-AuNCs was monitored by absorption and fluorescence spectroscopy. The UV-vis spectral characteristics of the separated DMF-AuNCs have been captured and they do not possess distinct surface plasmon resonance bands, indicating that all DMF-AuNCs are small AuNCs. The photoluminescence emission spectra of the separated DMF-AuNCs are in the blue-light region. Moreover, cationic DMF-AuNCs are for the first time identified by ion chromatography. Our proposed RP-HPLC methodology has been successfully applied to separate AuNCs of

  2. Development and validation of a high performance liquid chromatography method to determine linezolid concentrations in pig pulmonary tissue.

    Science.gov (United States)

    Guerrero, Laura; Martínez-Olondris, Pilar; Rigol, Montserrat; Esperatti, Mariano; Esquinas, Cristina; Luque, Néstor; Piñer, Raquel; Torres, Antoni; Soy, Dolors

    2010-03-01

    Linezolid is the first synthetic compound of a new group of antimicrobials, the oxazolidinones, which inhibit protein synthesis. It shows a broad spectrum of activity against Gram positive organisms. With respect to its pharmacokinetics, linezolid shows a relatively high volume of distribution and good penetration into inflammatory fluids, bone, fat and muscle. A reversed-phase isocratic high-performance liquid chromatographic method for linezolid analysis in piglet pulmonary tissue is described. Tissue samples and controls were prepared in 1 x TBE (1 M Tris, 0.9 M boric acid, 0.01 M EDTA). The mobile phase consisted of 20% ultrafiltered water and 80% of (A) 15 mM potassium monohydrogen phosphate buffer (pH = 5) with (B) acetonitrile (80%/20%; v/v). Samples were homogenized and precipitated with HClO(4) 3% (1/1, v/v). The injection volume was 100 microL. Ofloxacin was used as an internal standard. The assay was linear over a linezolid concentration range: 1.6-100 microg/mL. The method provided good validation data (n = 15): inaccuracy (3.6%), intra and inter-day variability (4.2% and 5.2%, respectively), recovery (91.8%), limit of detection (0.8 microg/mL) and quantitation (1.6 microg/mL) and acceptable stability within 24 h in the auto-sampler. The method offers a fast and simple approach to determine linezolid in pulmonary tissue which could be of use in pharmacokinetic studies.

  3. Determination of avermectins by the internal standard recovery correction - high performance liquid chromatography - quantitative Nuclear Magnetic Resonance method.

    Science.gov (United States)

    Zhang, Wei; Huang, Ting; Li, Hongmei; Dai, Xinhua; Quan, Can; He, Yajuan

    2017-09-01

    Quantitative Nuclear Magnetic Resonance (qNMR) is widely used to determine the purity of organic compounds. For the compounds with lower purity especially molecular weight more than 500, qNMR is at risk of error for the purity, because the impurity peaks are likely to be incompletely separated from the peak of major component. In this study, an offline ISRC-HPLC-qNMR (internal standard recovery correction - high performance liquid chromatography - qNMR) was developed to overcome this problem. It is accurate by excluding the influence of impurity; it is low-cost by using common mobile phase; and it extends the applicable scope of qNMR. In this method, a mix solution of the sample and an internal standard was separated by HPLC with common mobile phases, and only the eluents of the analyte and the internal standard were collected in the same tube. After evaporation and re-dissolution, it was determined by qNMR. A recovery correction factor was determined by comparison of the solutions before and after these procedures. After correction, the mass fraction of analyte was constant and it was accurate and precise, even though the sample loss varied during these procedures, or even in bad resolution of HPLC. Avermectin B1a with the purity of ~93% and the molecular weight of 873 was analyzed. Moreover, the homologues of avermectin B1a were determined based on the identification and quantitative analysis by tandem mass spectrometry and HPLC, and the results were consistent with the results of traditional mass balance method. The result showed that the method could be widely used for the organic compounds, and could further promote qNMR to become a primary method in the international metrological systems. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Molecularly imprinted monolith coupled on-line with high performance liquid chromatography for simultaneous quantitative determination of cyromazine and melamine.

    Science.gov (United States)

    Wang, Shanshan; Li, Daomin; Hua, Zhendong; Zhao, Meiping

    2011-09-21

    We report a novel method for simultaneous determination of cyromazine and melamine based on a molecularly imprinted monolith on-line coupled with high performance liquid chromatography (HPLC). The imprinted monolith was prepared by in situ polymerization using 2,4-diamino-6-undecyl-1,3,5-triazine (DAUTA) as a mimic template. Due to the better solubility of DAUTA in chloroform, hydrogen bonds were effectively developed between the template and the functional monomer and resulted in the formation of highly specific cavities in the obtained imprinted monolith. With methanol as the loading solvent, cyromazine and melamine were both selectively retained by the obtained imprinted monolith, while the nonspecific adsorption on the non-imprinted monolith was negligible. The imprinted monolithic column was on-line coupled with HPLC for purification and concentration of the two analytes from milk samples. To minimize the peak broadening during the on-line transfer of the analytes from the imprinted monolith to the following analytical column, a successive desorption program was developed for the elution step, which enabled on-line stacking of the target compounds before being analyzed by HPLC. Low detection limits of 0.12 μg mL(-1) for melamine and 0.05 μg mL(-1) for cyromazine were achieved with only 0.3 mL of milk sample and a low sensitivity HPLC-UVD instrument. The method may be further extended to detect other analytes of interest in a large variety of samples.

  5. Lipophilic marine toxins discovered in the Bohai Sea using high performance liquid chromatography coupled with tandem mass spectrometry.

    Science.gov (United States)

    Liu, Yang; Yu, Ren-Cheng; Kong, Fan-Zhou; Li, Chen; Dai, Li; Chen, Zhen-Fan; Zhou, Ming-Jiang

    2017-09-01

    Some dinoflagellates can produce lipophilic marine toxins, which pose potent threats to seafood consumers. In the Bohai Sea, an important semi-closed inland sea with intensive mariculture industry in China, there is little knowledge concerning lipophilic marine toxins and their potential threats. In this study, net-concentrated phytoplankton samples were periodically collected from 5 typical mariculture zones around the Bohai Sea, including Laishan (LS), Laizhou (LZ), Hangu (HG), Qinhuangdao (QHD) and Huludao (HLD) in 2013 and 2014, and a method using high performance liquid chromatography (HPLC) coupled with a Q-Trap mass spectrometer was applied to analyze seven representative lipophilic marine toxins, including okadaic acid (OA), dinophysistoxin-1 (DTX1), pectenotoxin-2 (PTX2), yessotoxin (YTX), azaspiracid-1 (AZA1), gymnodimine (GYM), and 13-desmethyl spirolide C (desMeC). The method had high sensitivity and repeatability, and exhibited satisfactory recoveries for most of the lipophilic marine toxins (92.1-108%) except for AZA1 (65.8-68.9%). Nearly all the lipophilic marine toxins could be detected in phytoplankton samples from the Bohai Sea. OA, DTX1 and PTX2 were predominant components and present in most of the phytoplankton samples. The maximum content of lipophilic marine toxin in phytoplankton samples concentrated from seawater (OA 464 pg L-1; DTX1 783 pg L-1; YTX 86.6 pg L-1; desMeC 15.6 pg L-1; PTX2 1.11 × 103 pg L-1) appeared in June 2014. Based on toxins present in phytoplankton samples, it is implied that seafood in the Bohai Sea is more likely to be contaminated by OA group and PTX group toxins, and spring is the high-risk season for toxin contamination. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. A novel on-line gold nanoparticle-catalyzed luminol chemiluminescence detector for high-performance liquid chromatography.

    Science.gov (United States)

    Zhang, Qun Lin; Wu, Liang; Lv, Chen; Zhang, Xiao Yue

    2012-06-15

    A novel on-line gold nanoparticle-catalyzed luminol-H(2)O(2) chemiluminescence (CL) detector for high-performance liquid chromatography (HPLC) was established, in which gold nanoparticles were produced by the on-line reaction of H(2)O(2), NaHCO(3)-Na(2)CO(3) (buffer solution of luminol), and HAuCl(4). Eight phenolic compounds (gallic acid, protocatechuic acid, protocatechuic aldehyde, 2,5-dihydroxybenzoic acid, caffeic acid, 2,3-dihydroxybenzoic acid, (+)-catechin, and (-)-epicatechin) were chosen as the model compounds. Every separated phenolic compound in the column eluent strongly enhanced the CL signal of on-line gold nanoparticle-catalyzed luminol system. The CL and UV-visible absorption spectra and transmission electron microscopy studies were carried out, and the CL enhancement mechanism was ascribed to that the presence of phenolic compound promoted the on-line formation of 38-nm-diameter gold nanoparticles, which better catalyzed the luminol-H(2)O(2) CL reaction. The effects of methanol and phosphoric acid in the proposed HPLC configuration were performed by two gradient elution programs, and the baseline profile revealed that on-line gold nanoparticle-catalyzed luminol-H(2)O(2) CL detector had better compatibility than 38 nm gold colloids-luminol-H(2)O(2) CL detector. The proposed CL detector exhibits excellent analytical performance with the low detection limit (S/N=3) of 0.53-0.97 ng/mL (10.6-19.4 pg) phenolic compounds, and offers a new strategy for developing on-line nanoparticle-catalyzed CL detector for HPLC with sensitive analysis. Copyright © 2012 Elsevier B.V. All rights reserved.

  7. Discrimination of wild Paris based on near infrared spectroscopy and high performance liquid chromatography combined with multivariate analysis.

    Directory of Open Access Journals (Sweden)

    Yanli Zhao

    Full Text Available Different geographical origins and species of Paris obtained from southwestern China were discriminated by near infrared (NIR spectroscopy and high performance liquid chromatography (HPLC combined with multivariate analysis. The NIR parameter settings were scanning (64 times, resolution (4 cm(-1, scanning range (10,000 cm(-1∼4000 cm(-1 and parallel collection (3 times. NIR spectrum was optimized by TQ 8.6 software, and the ranges 7455∼6852 cm(-1 and 5973∼4007 cm(-1 were selected according to the spectrum standard deviation. The contents of polyphyllin I, polyphyllin II, polyphyllin VI, and polyphyllin VII and total steroid saponins were detected by HPLC. The contents of chemical components data matrix and spectrum data matrix were integrated and analyzed by partial least squares discriminant analysis (PLS-DA. From the PLS-DA model of NIR spectrum, Paris samples were separated into three groups according to the different geographical origins. The R(2X and Q(2Y described accumulative contribution rates were 99.50% and 94.03% of the total variance, respectively. The PLS-DA model according to 12 species of Paris described 99.62% of the variation in X and predicted 95.23% in Y. The results of the contents of chemical components described differences among collections quantitatively. A multivariate statistical model of PLS-DA showed geographical origins of Paris had a much greater influence on Paris compared with species. NIR and HPLC combined with multivariate analysis could discriminate different geographical origins and different species. The quality of Paris showed regional dependence.

  8. Urinary metabolomic analysis of intrahepatic cholestasis of pregnancy based on high performance liquid chromatography/mass spectrometry.

    Science.gov (United States)

    Ma, Li; Zhang, Xiaoqing; Pan, Feng; Cui, Yue; Yang, Ting; Deng, Linlin; Shao, Yong; Ding, Min

    2017-08-01

    Intrahepatic cholestasis of pregnancy (ICP), a pregnancy-related liver disease, leads to complications for both mothers and fetuses. Metabolomic approach has been applied to maternal-fetal medicine. The global metabolomic alterations that are specific in ICP as yet have not been investigated. Based on high performance liquid chromatography/hybrid quadrupole time-of-flight (HPLC/Q-TOF) mass spectrometry, the untargeted metabolomics was used to analyze the changes of urinary metabolites between ICP group and the control group. One hundred nine variables in positive model and 119 variables in negative model were significantly different (pimportance in the project) score>1 by the orthogonal partial least squares discriminant analysis (OPLS-DA). 14 metabolites in positive model and 18 metabolites in negative model were selected and identified based on HMDB (human metabolome database). Most of these metabolites were involved in bile acids biosynthesis and metabolism, hormone metabolism and lipid metabolism. A metabolite panel (MG (22:5), LysoPE (22:5), l-homocysteine sulfonic acid, glycocholic acid and chenodeoxycholic acid 3-sulfate) was contrusted by the binary logistic regression analysis with high diagnostic accuracy for ICP. The area under the receiver operating characteristic curve was 0.988 with the sensitivity of 90.0% and specificity of 93.3%. Urinary metabolites allow for the discrimination of ICP from the controls by orthogonal partial least squares discriminant analysis. Therefore, these findings may provide deep insights for the etiopathogenesis of ICP. Moreover, the maternal urinary metabolite panel has the potential to be used as non-invasive biomarkers for the diagnosis of ICP. Copyright © 2017. Published by Elsevier B.V.

  9. Estimation of Rabeprazole Sodium and Itopride Hydrochloride in Tablet Dosage Form Using Reverse Phase High Performance Liquid Chromatography

    Directory of Open Access Journals (Sweden)

    Shaik Harum Rasheed

    2011-01-01

    Full Text Available A reversed phase high performance liquid chromatography (RP-HPLC method was developed, validated and used for the quantitative determination of rabeprazole sodium (RP and itopride hydrochloride (IH, from its tablet dosage form. Chromatographic separation was performed on a Phenomenex C18 column (250 mm × 4.6 mm, 5 μm, with a mobile phase comprising of a mixture of 50 mM ammonium acetate buffer and methanol (20:80v/v, pH 4.5 adjusted with acetic acid, at a flow rate of 1.3 mL/min with detection at 286 nm. Separation was completed in less than 10 min. As per International Conference on Harmonization (ICH guidelines the method was validated for linearity, accuracy, precision, limit of quantitation and limit of detection. Linearity of RP was found to be in the range of 37.5-375 μg/mL and IH was found to be in the range of 5-50 μg/mL. The correlation coefficients were 0.9997 and 0.9995 for RB and IH respectively. The accuracy of the developed method was found to be 98.6-100.7 for RP and 99.42 -100.81 for IH. The experiment shows the developed method is free from interference of excipients. It indicates the developed RP-HPLC method is simple, linear, precise and accurate and it can be conveniently adopted for the routine quality control analysis of the tablet dosage form.

  10. Development of a Microemulsion High Performance Liquid Chromatography (MELC Method for Determination of Salbutamol in Metered-Dose Inhalers (MDIS

    Directory of Open Access Journals (Sweden)

    J Hanaee

    2013-02-01

    Full Text Available Introduction: A sensitive and rapid oil-in-water (O/W microemulsion high performance liquid chromatography (MELC method has been developed. The water-in-oil (w/o microemulsion was used as a mobile phase in the determination of salbutamol in aqueous solutions. In addition, the influence of operating parameters on the separation performance was examined. Methods: The samples were injected into C18, (250mm×4.6mm analytical columns maintained at 25oC with a flow rate 1 ml/min. The mobile phase was 95.5% v/v aqueous orthophosphate buffer 20 mM (adjusted to pH 3 with orthophosphoric acid, 0.5% ethyl acetate, 1.5% Brij35, and 2.5% 1-butanol, all w/w. The salbutamol and internal standard peaks were detected by fluorescence detection at the excitation and emission wavelengths of 267 and 313 nm respectively. Results: The method had an accuracy of > 97.78% and the calibration curve was linear (r2 = 0.99 over salbutamol concentrations ranging from 25 to 500 ng/mL. The intra-day and inter-day precisions (CV % were <1.6 and <1.8, respectively. The limit of detection (LOD and limit of quantitation (LOQ were 9.61ng/ml and 29.13ng/ml, respectively. Conclusion: The method reported is simple, precise and accurate, and has the capacity to be used for determination of salbutamol in the pharmaceutical preparation.

  11. Development of a high-performance liquid chromatography method for the determination of florfenicol in animal feedstuffs.

    Science.gov (United States)

    Yang, JinJing; Sun, GuiZhi; Qian, MingRong; Huang, LingLi; Ke, XianBing; Yang, Bo

    2017-11-15

    An effective thin layer chromatography (TLC) purification procedure coupled to high-performance liquid chromatography (HPLC) method was developed for the determination of florfenicol (FF) in pig, chicken and fish feedstuffs. The feedstuff samples were extracted with ethyl acetate, defatted with n-hexane saturated with acetonitrile, and further purified by TLC. The chromatographic separation was performed on a Waters Symmetry C18 column using an isocratic procedure with acetonitrile-water (35:65, v/v) at 0.6mL/min. The ultraviolet (UV) detector was set at a wavelength of 225nm. The FF concentrations in feedstuff samples were quantified using a standard curve. Good linear correlations (y=159075x-15054, r>0.9999) were achieved within the concentration range of 0.05-200μg/mL. The recoveries of FF spiked at levels of 1, 100 and 1000μg/g ranged from 80.6% to 105.3% with the intra-day and inter-day relative standard deviation (RSD) less than 9.3%. The limit of detection (LOD) and limit of quantitation (LOQ) were 0.02 and 0.06mg/kg for pig feedstuffs, 0.02 and 0.07mg/kg for chicken feedstuffs, and 0.02 and 0.05mg/kg for fish feedstuffs, respectively. This reliable, simple and cost-effective method could be applied to the routine monitoring of FF in animal feedstuffs. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Beyond-use date determination of buprenorphine buccal solution using a stability-indicating high-performance liquid chromatographic assay.

    Science.gov (United States)

    Kirk, Loren Madden; Brown, Stacy D

    2015-12-01

    The objectives of this study included developing and validating a stability-indicating high-performance liquid chromatographic (HPLC) method with ultraviolet (UV) detection for the determination of buprenorphine in a buccal solution for veterinary use, and applying that method to determine the stability of a 3 mg/ml buprenorphine preparation in room temperature and refrigerated storage conditions. This preparation, intended for buccal administration in feline patients, plays an important role in pain management in cats. A stability-indicating HPLC method was developed and validated for system suitability, accuracy, repeatability, intermediate precision, specificity, linearity and robustness based on US Pharmacopeia (USP) General Chapter . The method was then applied to the study of potency changes over 90 days in a buccal buprenorphine solution stored at two temperatures. All HPLC-UV method data met acceptable criteria for the quantification of buprenorphine in a buccal solution formulation. The buprenorphine concentrations found in each stability sample remained within the 90-110% of label claim throughout the 90 days of study. All stability test bottles of the buprenorphine buccal solution retained their original appearance. For the room temperature bottles, some white particulate matter was noted in the threads of the container bottles starting at day 21. The pH of the preparations during the course of the study was in the range of 3.57-4.06 and 4.01-4.16 for the room temperature and refrigerated samples, respectively. Pharmacists have compounded a concentrated 3 mg/ml buccal solution to use easily in the home care or outpatient setting for treatment of feline pain. Prior to this investigation, pharmacists empirically assigned beyond-use dates to this formulation based on standards in USP General Chapter Pharmaceutical Compounding - Nonsterile Preparations. This study of a 3 mg/ml buprenorphine buccal solution indicates stability through 90 days. © ISFM and

  13. Magnetic graphene solid-phase extraction for the determination of carbamate pesticides in tomatoes coupled with high performance liquid chromatography.

    Science.gov (United States)

    Li, Na; Chen, Juan; Shi, Yan-Ping

    2015-08-15

    Graphene-based magnetic nanoparticles, comprising zero-valent iron, iron oxide-oxyhydroxide and graphene, were prepared through a simple one-step synthesis method, and subsequently applied to magnetic solid-phase extraction for the determination of trace carbamate pesticides in tomatoes coupled with high performance liquid chromatography. The properties of the nanocomposites were confirmed by using Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and vibrating sample magnetometer. The components within the nanocomposites endowed the material with high extraction performance and manipulative convenience. Compared with reduced graphene oxide, the as-prepared G-MNPs showed the better extraction efficiencies for the carbamate pesticides thanks to the contribution of the iron-containing magnetic nanoparticles to the adsorption capacity of the nanocomposites. Various experimental parameters affecting the extraction efficiency had been investigated in detail. Under the optimal conditions, the method provided high enrichment factors ranging from 364 to 434, good linearities ranging from 5 to 200ng g(-1) for metolcarb, baygon and methiocarb and 10 to 200ng g(-1) for carbofuran and isoprocarb, low limits of detection ranging from 0.58 to 2.06ng g(-1), and satisfactory spiked recoveries (between 90.34% and 101.98% with the relative standard deviation values from 1.21% to 5.93%). It was confirmed that this novel method was an efficient pretreatment and enrichment procedure and could be successfully applied for extraction and determination of trace carbamate pesticides in complex matrices. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. Multiresidue analysis of fluoroquinolone antimicrobials in chicken meat by molecularly imprinted solid-phase extraction and high performance liquid chromatography.

    Science.gov (United States)

    Urraca, J L; Castellari, M; Barrios, C A; Moreno-Bondi, M C

    2014-05-23

    This paper describes the synthesis of novel molecularly imprinted polymer (MIP) micro-beads for the selective extraction (MISPE) of six fluoroquinolone (FQ) antibiotics (enrofloxacin, ciprofloxacin, lomefloxacin, danofloxacin, sarafloxacin and norfloxacin) from chicken muscle samples and further analysis by high-performance liquid chromatography (HPLC) with fluorescence (FLD) or mass spectrometry (MS) detection. A combinatorial screening approach has been applied to select the optimal functional monomer and cross-linker formulation for polymer synthesis. The MIP prepared using enoxacin (ENOX) as the template - a mixture of methacrylic acid (MAA) and trifluoromethacrylic acid (TFMAA) as functional monomers and ethylene glycol dimethacrylate (EDMA) as the cross-linker - showed superior FQ recognition properties than the rest of the materials generated. MIP spherical particles were prepared using silica beads as sacrificial scaffolds. The polymers were packed in solid phase extraction (SPE) cartridges. The optimized MISPE-HPLC method allows the extraction of the antimicrobials from aqueous samples followed by a selective washing with acetonitrile/water (0.005% TFA, pH=3.0), 20:80 (v/v) and elution with 5% trifluoroacetic acid in methanol. Optimum MISPE conditions led to recoveries of the target FQs in chicken muscle samples ranging between 68 and 102% and precisions in the 3-4% range (RSD, n=18). The method has been validated according to European Union Decision 2002/657/EC, in terms of linearity, accuracy, precision, selectivity, decision limit (CCα) and detection capability (CCβ) by HPLC-FLD and HPLC-MS/MS. The limits of detection were improved using HPLC-MS/MS analysis and ranged between 0.2 and 2.7μgkg(-1) (S/N=3) for all the FQs tested. Copyright © 2014 Elsevier B.V. All rights reserved.

  15. Determination of metolcarb and diethofencarb in apples and apple juice by solid-phase microextraction-high performance liquid chromatography.

    Science.gov (United States)

    Yang, Xiu-Min; Wang, Ou; Wang, Ming-Zhao; Hu, Yan-Xue; Li, Wei-Ning; Wang, Zhi

    2008-09-01

    A method for the determination of metolcarb and diethofencarb in apples and apple juice is developed using solid-phase microextraction (SPME) coupled with high-performance liquid chromatography (HPLC). The experimental conditions of SPME, such as the kind of extraction fiber, extraction time, stirring rate, pH of the extracting solution, and desorption conditions are optimized. The SPME is performed on a 60 microm polydimethylsiloxane/divinylbenzene fiber for 40 min at room temperature with the solution being stirred at 1100 rpm. The extracted pesticides on the SPME fiber are desorbed in the mobile phase into SPME-HPLC interface for HPLC analysis. Separations are carried out on a Baseline C18 column (4.6 i.d. x 250 mm, 5.0 microm) with acetonitrile-water (55/45, v/v) as the mobile phase at a flow rate of 1.0 mL/min, and photodiode-array detection at 210 nm. For apple samples, the method is linear for both metolcarb and diethofencarb in the range of 0.05-1.0 mg/kg (r > 0.99), with a detection limit (S/N = 3 ) of 15 and 5 microg/kg, respectively. For apple juice, the method is linear for both metholcarb and diethofencarb over the range of 0.05-1.0 mg/L (r > 0.99) with the detection limit (S/N = 3 ) of 15 and 3 microg/L, respectively. Excellent recovery and reproducibility values are achieved. The proposed method is shown to be simple, sensitive, and organic solvent-free, and is suitable for the determination of the two pesticides in apples and apple juice.

  16. [Determination of the contents of vitamin C and its derivatives in cosmetics by high performance liquid chromatography].

    Science.gov (United States)

    Chen, Peijin; Yan, Zhi; Tu, Xiaoke; Xiao, Feng; Liang, Hong

    2015-07-01

    A method has established for the detection of vitamin C (VC) and its derivatives (ascorbyl glucoside, AA-2G; magnesium ascorbyl phosphate, AA-2P; ascorbic acid ethyl ether, Only VCE) in cosmetics by high performance liquid chromatography (HPLC). Low fat cosmetic samples such as make-up water and lotion were extracted directly with 30 mL 0.02 mol/L potassium dihydrogen phosphate solution (pH 3.0). High fat cosmetic samples such as face cream and gel were well dispersed with 1.0 mL dichloromethane first, then extracted with 25 mL 0.02 mol/L potassium dihydrogen phosphate solution (pH 3.0). The sample solution was centrifuged with a speed of 12,000 r/min, then filtered through a 0.22 μm syringe filter. The filtrate was analyzed on a column of YMC-Triart C18 (250 mm x 4.6 mm, 5 μm) using 0.02 mol/L potassium dihydrogen phosphate solution (pH 3.0) and methanol as mobile phases with a flow rate of 1.0 mL/min. The temperature of the column was 25 °C and the detection wavelength was 250 nm. The standard working curves of the four analytes had good linear relationship (r2>0.9999). The detection limits of the four analytes were 0.04-0.08 g/kg (S/N=10). The recoveries were 95.6%-101.0% with the relative standard deviations of 0.62%-3.0% at the spiked levels of 0.25-5.0 g/kg. This method is a simple, rapid, exact and reliable for the determination of the contents of vitamin C and its derivatives in cosmetics.

  17. High-performance liquid chromatographic determination of arbutin in skin-whitening creams and medicinal plant extracts.

    Science.gov (United States)

    Thongchai, Wisanu; Liawruangrath, Boonsom; Liawruangrath, Saisunee

    2007-01-01

    A high-performance liquid chromatographic method was developed for quantitative analysis of arbutin. The arbutin was separated on an ODS Hypersil C(18) column with a mobile phase of water:methanol:0.1 M hydrochloric acid (89:10:1, v/v/v). The level of arbutin was measured by means of UV detection at 222 nm. The optimum conditions for arbutin quantitative analysis were investigated. The calibration curve was found to be linear up to 1,000 microg/ml(-1) of arbutin concentration, and the working calibration curve for arbutin determination over the range 0.5-30.0 microg/ml(-1) of arbutin (r(2)=0.9999) was established. The relative standard deviations for intraday and interday were found to be 0.98% and 1.15%, respectively. A detection limit (3sigma) and quantitation limit (10sigma) of 0.02 microg/ml(-1) and 0.2 microg/ml(-1), respectively, and a mean percentage recovery of the spiked arbutin of 99.88 +/- 1.12% were obtained. The proposed method has been applied to the determination of arbutin in commercial skin-whitening creams (Arbuwhite cream, Super Whitening cream, and Shiseido cream) with average contents of 7.60, 5.30, and 57.90 mg/g(-1), respectively. It was also applied to the determination of arbutin in medicinal plant extracts from Betula alnoides Buch. Ham., Clerodendrum petasites S. Moore, Curculigo latifolia Dryand. Var. latifolia, and Hesperethusa crenulata (Roxb.) Roem, levels of which were found to be 3.50, 1.50, 1.10, and 0.12 microg/g(-1), respectively (no article reported in the literature about arbutin analysis). The proposed HPLC method is rapid, simple, and selective for routine analysis.

  18. Quantification of patulin in fruit leathers by ultra-high-performance liquid chromatography-photodiode array (UPLC-PDA).

    Science.gov (United States)

    Maragos, Chris M; Busman, Mark; Ma, Liang; Bobell, John

    2015-01-01

    Patulin is a mycotoxin commonly found in certain fruit and fruit products. For this reason many countries have established regulatory limits pertaining to, in particular, apple juice and apple products. Fruit leathers are produced by dehydrating fruit puree, leaving a sweet product that has a leathery texture. A recent report in the literature described the detection of patulin at substantial levels in fruit leathers. To investigate this further, an ultra-high-performance liquid chromatography-photodiode array (UPLC-PDA) method was developed for the sensitive detection of patulin in fruit leathers. Investigations were also made of the suitability of direct analysis in real time-mass spectrometry (DART-MS) for detection of patulin from the surface of fruit leathers. Results indicated DART-MS was insufficiently sensitive for quantification from the surface of home-style apple leathers, although patulin spiked onto the surface of leather or peel could be detected. The UPLC-PDA method was used to determine the fate of patulin during the preparation of home-made fruit leathers. Interestingly, when a home-style process was used, the patulin was not destroyed, but rather increased in concentration as the puree was dehydrated. The UPLC-PDA method was also used to screen for patulin in commercial fruit leathers. Of the 36 products tested, 14 were above the limit of detection (3.5 μg kg(-1)) and nine were above the limit of quantification (12 μg kg(-1)). Positive samples were confirmed by UPLC-MS/MS. Only one sample was found above the US regulatory limit for single-strength apple juice products (50 μg kg(-1)). These results suggest patulin can be concentrated during preparation and can be found in fruit leathers. The limited survey suggests that patulin is fairly prevalent in such commercial products, but that the levels are usually low.

  19. [Optimum separation conditions of catechin compounds by HCI program in reversed-phase high performance liquid chromatography].

    Science.gov (United States)

    Jin, Yinzhe; Row, Kyung Ho

    2006-09-01

    An efficient optimization method was used to separate catechin compounds by reversed-phase high performance liquid chromatography (RP-HPLC). The binary mobile phase of water and methanol was utilized with the buffer of acetic acid (AA). The elution profiles were calculated by the plate theory based on the linear and quadratic equations of retention factor, In k = ln kw + SF, k = A + B/F, ln k = L + MF + NF2, where F is the volume fraction of methanol in the mobile phase. The retention theory was modified to calculate the elution profile in both isocratic and gradient modes. Based on the retention theory, elution profiles were predicted by introducing the concept of solute migration in the mobile phase with the linear and quadratic dependence of ln k in terms of the organic modifier content. Using the HCI program (a software designed by Inha University), the recommended experimental conditions of mobile phase composition and gradient step were suggested, and the elution profiles calculated by the quadratic relationship of ln k showed better coincidence with the experimental data than the linear correlation did. The calculated results of mobile phase condition for separation of catechin compounds suggested that the mobile phase composition was 0.1% AA in water/0.1% AA in methanol, 75/25 (v/v), then after 15 min, the composition was linearly changed to 50/50 (v/v) in 10 min and held at the isocratic mode to the end. In the experimental conditions, the agreement between the experimental elution profiles and the calculated values of eluted concentration was relatively good.

  20. Fast separation and quantification of three anti-glaucoma drugs by high-performance liquid chromatography UV detection

    Directory of Open Access Journals (Sweden)

    Mohamed Walash

    2016-04-01

    Full Text Available In this study, a simple and accurate high-performance liquid chromatography method was developed and validated for fast separation of three anti-glaucoma drugs: timolol maleate (TM, brimonidine tartrate (BM, and latanoprost (LP. Separation of the three drugs was achieved in < 6 minutes using a BDS Hypersil phenyl column and a mobile phase consisting of acetonitrile: 25mM phosphate buffer, pH 4.0 (50: 50, v/v at 1.2 mL/min with UV detection at 210 nm. The method was linear over the concentration ranges of 5.0–200.0 μg/mL, 2.0–80.0 μg/mL and 1.0–25.0 μg/mL with lower detection limits of 0.21 μg/mL, 0.10 μg/mL and 0.11 μg/mL for TM, BM and LP, respectively. The method was applied for the determination of two fixed-dose combination eye drops for the treatment of glaucoma, containing TM together with either BM or LP. Commercial samples of single-ingredient ophthalmic solutions containing the studied drugs were also successfully analyzed. The results obtained by the proposed method were favorably compared with those obtained by the comparison methods using Student's t test and the variance ratio F test.

  1. Discrimination of wild Paris based on near infrared spectroscopy and high performance liquid chromatography combined with multivariate analysis.

    Science.gov (United States)

    Zhao, Yanli; Zhang, Ji; Yuan, Tianjun; Shen, Tao; Li, Wei; Yang, Shihua; Hou, Ying; Wang, Yuanzhong; Jin, Hang

    2014-01-01

    Different geographical origins and species of Paris obtained from southwestern China were discriminated by near infrared (NIR) spectroscopy and high performance liquid chromatography (HPLC) combined with multivariate analysis. The NIR parameter settings were scanning (64 times), resolution (4 cm(-1)), scanning range (10,000 cm(-1)∼4000 cm(-1)) and parallel collection (3 times). NIR spectrum was optimized by TQ 8.6 software, and the ranges 7455∼6852 cm(-1) and 5973∼4007 cm(-1) were selected according to the spectrum standard deviation. The contents of polyphyllin I, polyphyllin II, polyphyllin VI, and polyphyllin VII and total steroid saponins were detected by HPLC. The contents of chemical components data matrix and spectrum data matrix were integrated and analyzed by partial least squares discriminant analysis (PLS-DA). From the PLS-DA model of NIR spectrum, Paris samples were separated into three groups according to the different geographical origins. The R(2)X and Q(2)Y described accumulative contribution rates were 99.50% and 94.03% of the total variance, respectively. The PLS-DA model according to 12 species of Paris described 99.62% of the variation in X and predicted 95.23% in Y. The results of the contents of chemical components described differences among collections quantitatively. A multivariate statistical model of PLS-DA showed geographical origins of Paris had a much greater influence on Paris compared with species. NIR and HPLC combined with multivariate analysis could discriminate different geographical origins and different species. The quality of Paris showed regional dependence.

  2. Simultaneous determination of vasicine and vasicinone by High-performance liquid chromatography in roots of eight Sida species.

    Science.gov (United States)

    Subramanya, M D; Pai, Sandeep R; Ankad, Gireesh M; Hegde, Harsha V; Roy, Subarna; Hoti, S L

    2016-01-01

    Sida L. is a medicinally important genus widely used in conventional systems of medicine in India. The present study aims toward simultaneous determination of two bioactive compounds vasicine and vasicinone in root extracts of eight Sida spp. from Western Ghats, India. Determination of vasicine and vasicinone was undertaken in methanolic root extracts (10% w/v) of Sida acuta, Sida cordata, Sida cordifolia, Sida rhombifolia, Sida spinosa, Sida indica, Sida retusa and Sida mysorensis by high performance liquid chromatography (HPLC) method. The standards were prepared with the concentration of mg/mL. Data were expressed as mean values of three reading and relative standard deviations. The separation was achieved on a Waters, Nova-Pack, C18 (250 mm × 4.6 mm, 5 μ) column, with acetonitrile - 0.1 M phosphate buffer-glacial acetic acid (15: 85: 1, v/v/v) as solvent system at a flow-rate of 1.0 mL/min. The effluent was monitored using ultraviolet detection at a wavelength of 300 nm. Both calibration curves of standard showed good linear regression (R2 > 0.994). The limit of detection and the limit of quantification for vasicine was 0.110 and 0.333 μg/mL and for vasicinone was 0.059 and 0.179 μg/mL respectively. The vasicine content was highest in S. cordifolia (9.891 ± 0.495 μg/100 mg) and vasicinone content was rich in S. cordata (33.013 ± 1.651 μg/100 mg.) The content of vasicinone was higher than vasicine. HPLC method provides simple, accurate, and reproducible quantitative analysis for simultaneous determination of vasicine and vasicinone. Among the selected Sida species, S. cordifolia and S. cordata were found to be rich in the vasicine and vasicinone contents, respectively.

  3. Analysis of Levodopa Content in Commercial Mucuna pruriens Products Using High-Performance Liquid Chromatography with Fluorescence Detection.

    Science.gov (United States)

    Soumyanath, Amala; Denne, Tanya; Hiller, Amie; Ramachandran, Shaila; Shinto, Lynne

    2018-02-01

    Mucuna pruriens (MP) seeds contain levodopa (up to 2% by weight) and have been used in traditional Indian medicine to treat an illness named "Kampavata," now understood to be Parkinson's disease (PD). Studies have shown MP to be beneficial, and even superior, to levodopa alone in treating PD symptoms. Commercial products containing MP are readily available from online and retail sources to patients and physicians. Products often contain extracts of MP seeds, with significantly higher levodopa content than the seeds. However, MP products have limited regulatory controls with respect to quality and content of active ingredient. The aim of this study was to apply a quantitative method to determine levodopa content in readily available MP products that might be used by patients or in research studies. Levodopa present in six commercial MP products was quantified by solvent extraction followed by reversed-phase high-performance liquid chromatography (HPLC) coupled to fluorescence detection (FD). Certificates of analysis (COA) were obtained, from manufacturers of MP products, to assess the existence and implementation of specifications for levodopa content. HPLC-FD analysis revealed that the levodopa content of the six commercial MP products varied from 6% to 141% of individual label claims. No product contained levodopa within normal pharmacopeial limits of 90%-110% label claim. The maximum daily dose of levodopa delivered by the products varied from 14.4 to 720 mg/day. COAs were inconsistent in specifications for and verification of levodopa content. The commercial products tested varied widely in levodopa content, sometimes deviating widely from the label claim. These deficiencies could impact efficacy and safety of MP products used by PD patients and compromise the results of scientific studies on MP products. The HPLC-FD method described in this study could be utilized by both manufacturers and scientific researchers to verify levodopa content of MP products.

  4. Analysis of tilianin and acacetin inAgastache rugosaby high-performance liquid chromatography with ionic liquids-ultrasound based extraction.

    Science.gov (United States)

    Wei, Jinfeng; Cao, Pengran; Wang, Jinmei; Kang, Wenyi

    2016-01-01

    Ionic liquid 1-butyl-3-methylimidazolium bromide-methanol-based ultrasonic-assisted extraction (ILUAE) was used to extract tilianin and acacetin from the aerial parts of Agastache rugose ( A. rugose ), and simultaneously determined by reversed phase high performance liquid chromatographic (RP-HPLC) method with ultraviolet detection (RP-HPLC-UV). An InertSustain RP-C 18 column was used with the mobile phase consisting of methanol and 0.2% acetic acid as gradient elution at the detection wavelength of 332 nm. The flow rate was 0.8 mL/min, and the column temperature was 30 °C. Under the optimized conditions, tilianin and acacetin displayed good linearity in the ranges of 0.0595-4.76 and 0.0585-4.68 μg/mL, respectively, with the average recoveries being 96.93 and 97.88%, respectively. The method of ILUAE was compared with the traditional methods, it exhibited higher efficiency, higher reproducibility and environmental friendly in analyzing the active compounds in traditional Chinese medicines (TCMs).

  5. Optimization of dispersive liquid-phase microextraction based on solidified floating organic drop combined with high-performance liquid chromatography for the analysis of glucocorticoid residues in food.

    Science.gov (United States)

    Huang, Yuan; Zheng, Zhiqun; Huang, Liying; Yao, Hong; Wu, Xiao Shan; Li, Shaoguang; Lin, Dandan

    2017-05-10

    A rapid, simple, cost-effective dispersive liquid-phase microextraction based on solidified floating organic drop (SFOD-LPME) was developed in this study. Along with high-performance liquid chromatography, we used the developed approach to determine and enrich trace amounts of four glucocorticoids, namely, prednisone, betamethasone, dexamethasone, and cortisone acetate, in animal-derived food. We also investigated and optimized several important parameters that influenced the extraction efficiency of SFOD-LPME. These parameters include the extractant species, volumes of extraction and dispersant solvents, sodium chloride addition, sample pH, extraction time and temperature, and stirring rate. Under optimum experimental conditions, the calibration graph exhibited linearity over the range of 1.2-200.0ng/ml for the four analytes, with a reasonable linearity(r 2 : 0.9990-0.9999). The enrichment factor was 142-276, and the detection limits was 0.39-0.46ng/ml (0.078-0.23μg/kg). This method was successfully applied to analyze actual food samples, and good spiked recoveries of over 81.5%-114.3% were obtained. Copyright © 2017. Published by Elsevier B.V.

  6. Analyses of Indole Compounds in Sugar Cane (Saccharum officinarum L. Juice by High Performance Liquid Chromatography and Liquid Chromatography-Mass Spectrometry after Solid-Phase Extraction

    Directory of Open Access Journals (Sweden)

    Jean Wan Hong Yong

    2017-03-01

    Full Text Available Simultaneous quantitative analysis of 10 indole compounds, including indole-3-acetic acid (IAA, one of the most important naturally occurring auxins and some of its metabolites, by high performance liquid chromatography (HPLC and liquid chromatography-mass spectrometry (LC-MS after solid-phase extraction (SPE was reported for the first time. The analysis was carried out using a reverse phase HPLC gradient elution, with an aqueous mobile phase (containing 0.1% formic acid modified by methanol. Furthermore, a novel SPE procedure was developed for the pre-concentration and purification of indole compounds using C18 SPE cartridges. The combination of SPE, HPLC, and LC-MS was applied to screen for the indole compounds present in sugar cane (Saccharum officinarum L. juice, a refreshing beverage with various health benefits. Finally, four indole compounds were successfully detected and quantified in sugar cane juice by HPLC, which were further unequivocally confirmed by LC-MS/MS experiments operating in the multiple reaction monitoring (MRM mode.

  7. Magnetic ionic liquid aqueous two-phase system coupled with high performance liquid chromatography: A rapid approach for determination of chloramphenicol in water environment.

    Science.gov (United States)

    Yao, Tian; Yao, Shun

    2017-01-20

    A novel organic magnetic ionic liquid based on guanidinium cation was synthesized and characterized. A new method of magnetic ionic liquid aqueous two-phase system (MILATPs) coupled with high-performance liquid chromatography (HPLC) was established to preconcentrate and determine trace amount of chloramphenicol (CAP) in water environment for the first time. In the absence of volatile organic solvents, MILATPs not only has the excellent properties of rapid extraction, but also exhibits a response to an external magnetic field which can be applied to assist phase separation. The phase behavior of MILATPs was investigated and phase equilibrium data were correlated by Merchuk equation. Various influencing factors on CAP recovery were systematically investigated and optimized. Under the optimal conditions, the preconcentration factor was 147.2 with the precision values (RSD%) of 2.42% and 4.45% for intra-day (n=6) and inter-day (n=6), respectively. The limit of detection (LOD) and limit of quantitation (LOQ) were 0.14ngmL(-1) and 0.42ngmL(-1), respectively. Fine linear range of 12.25ngmL(-1)-2200ngmL(-1) was obtained. Finally, the validated method was successfully applied for the analysis of CAP in some environmental waters with the recoveries for the spiked samples in the acceptable range of 94.6%-99.72%. Hopefully, MILATPs is showing great potential to promote new development in the field of extraction, separation and pretreatment of various biochemical samples. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Selective on-line detection of boronic acids and derivatives in high-performance liquid chromatography eluates by post-column reaction with alizarin

    NARCIS (Netherlands)

    Duval, F.L.; Wardani, P.A.; Zuilhof, H.; Beek, van T.A.

    2015-01-01

    An on-line high-performance liquid chromatography (HPLC) method for the rapid and selective detection of boronic acids in complex mixtures was developed. After optimization experiments at an HPLC flow rate of 0.40 mL/min, the HPLC-separated analytes were mixed post-column with a solution of 75 µM

  9. Ultra-high-performance liquid chromatography-tandem mass spectrometry measurement of climbazole deposition from hair care products onto artificial skin and human scalp

    NARCIS (Netherlands)

    Chen, G.; Hoptroff, M.; Fei, X.; Su, Y.; Janssen, H.-G.

    2013-01-01

    A sensitive and specific ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method was developed and validated for the measurement of climbazole deposition from hair care products onto artificial skin and human scalp. Deuterated climbazole was used as the internal

  10. SENSITIVE METHOD FOR THE DETERMINATION OF VINCRISTINE IN HUMAN SERUM BY HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY AFTER ONLINE COLUMN-EXTRACTION

    NARCIS (Netherlands)

    BLOEMHOF, H; VANDIJK, KN; DEGRAAF, SSN; VENDRIG, DEMM; UGES, DRA

    1991-01-01

    A column-switching high-performance liquid chromatographic method was developed for the determination of vincristine in serum. Sample preparation was carried out by means of on-line column-extraction, using a C18 reversed-phase preconcentration column. This technique is simple (minimizing manual

  11. Determination of acylcarnitines in urine of patients with inborn errors of metabolism using high-performance liquid chromatography after derivatization with 4'-bromophenacylbromide

    NARCIS (Netherlands)

    Poorthuis, B. J.; Jille-Vlcková, T.; Onkenhout, W.

    1993-01-01

    A high-performance liquid chromatographic method is presented for the determination of urinary acylcarnitines. After solid phase extraction on silica columns the acylcarnitines are converted to 4'-bromophenacyl esters with 4'-bromophenacylbromide in the presence of N,N-diisopropylethylamine.

  12. High-performance liquid chromatography coupled to enzyme-amplified biochemical detection for the analysis of hemoglobin after pre-column biotinylation

    NARCIS (Netherlands)

    van Bommel, M.R.; Jong, A.P.J.M.; Tjaden, U.R.; Irth, H.; van der Greef, J.

    2000-01-01

    The determination of proteins with enzyme-amplified biochemical detection (EA-BCD) coupled on-line with high-performance liquid chromatography (HPLC) is demonstrated. The EA-BCD system was developed to detect biotin-containing compounds. Hemoglobin, which was used as a model compound, was

  13. Development of a method for quantitation of retinol and retinyl palmitate in human serum using high-performance liquid chromatography atmospheric pressure chemical ionization mass spectrometry.

    NARCIS (Netherlands)

    Breemen, van R.B.; Nikolic, D.; Xu, X.Y.; Xiong, Y.S.; Lieshout, van M.; West, C.E.; Schilling, A.B.

    1998-01-01

    A method for the quantitative analysis of the vitamin A compounds all-trans-retinol and all-trans-retinyl palmitate was developed using high-performance liquid chromatography-atmospheric pressure chemical ionization-mass spectrometry (APCI-LC-MS). Unlike previous quantitative mass spectrometric

  14. Simultaneous quantification of purine and pyrimidine bases, nucleosides and their degradation products in bovine blood plasma by high performance liquid chromatography tandem mass spectrometry

    DEFF Research Database (Denmark)

    Nielsen, Charlotte Stentoft; Vestergaard, Mogens; Løvendahl, Peter

    2014-01-01

    ), and their degradation products (uric acid, allantoin, β-alanine, β-ureidopropionic acid, β-aminoisobutyric acid) in blood plasma of dairy cows. The high performance liquid chromatography-based technique coupled to electrospray ionization tandem mass spectrometry (LC–MS/MS) was combined with individual matrix...

  15. Validation of a high performance liquid chromatography analysis for the determination of noradrenaline and adrenaline in human urine with an on-line sample purification

    DEFF Research Database (Denmark)

    Hansen, Åse Marie; Kristiansen, J; Nielsen, J L

    1999-01-01

    A high performance liquid chromatography (HPLC) method with fluorescence detection including an on-line purification was established for determination of catecholamines in human urine. The method was evaluated using samples of pooled urine spiked with catecholamines and validated for measurements...

  16. Implementation of Isavuconazole in a Fluorescence-Based High-Performance Liquid Chromatography Kit Allowing Simultaneous Detection of All Four Currently Licensed Mold-Active Triazoles

    DEFF Research Database (Denmark)

    Jorgensen, Rene; Andersen, Siri Rytcher; Astvad, Karen Marie Thyssen

    2017-01-01

    . The method involves using a kit from ChromSystems intended for TDM of itraconazole (ITZ), posaconazole (PSZ), and voriconazole (VRZ) in serum/plasma for sample preparation and high-performance liquid chromatography, using fluorescence detection with emission and excitation wavelengths set to 261 and 366 nm...

  17. Quantitative analysis of flavonols, flavones, and flavanones in fruits, vegetables and beverages by high-performance liquid chromatography with photo-diode array and mass spectrometric detection

    DEFF Research Database (Denmark)

    Justesen, U.; Knuthsen, Pia; Leth, Torben

    1998-01-01

    A high-performance liquid chromatographic (HPLC) separation method viith photo-diode array (PDA) and mass spectrometric (MS) detection was developed to determine and quantify flavonols, flavones, and flavanones in fruits, vegetables and beverages. The compounds were analysed as aglycones, obtained...

  18. Comparative oxidation state specific analysis of arsenic species by high-performance liquid chromatography-inductively coupled-mass spectrometry and hydride generation-cryotrapping-atomic absorption spectrometry

    Science.gov (United States)

    The formation of methylarsonous acid (MAsIII) and dimethylarsinous acid (DMAsIII) in the course of inorganic arsenic (iAs) metabolism plays an important role in the adverse effects of chronic exposure to iAs. High-performance liquid chromatography-inductively coupled plasma-mass ...

  19. Characterisation of chemical components for identifying historical Chinese textile dyes by ultra high performance liquid chromatography – photodiode array – electrospray ionisation mass spectrometer

    NARCIS (Netherlands)

    Han, J.; Wanrooij, J.; van Bommel, M.; Quye, A.

    2017-01-01

    This research makes the first attempt to apply Ultra High Performance Liquid Chromatography (UHPLC) coupled to both Photodiode Array detection (PDA) and Electrospray Ionisation Mass Spectrometer (ESI–MS) to the chemical characterisation of common textile dyes in ancient China. Three different

  20. Optimisation of high-performance liquid chromatography with diode array detection using an automatic peak tracking procedure based on augmented iterative target transformation factor analysis

    NARCIS (Netherlands)

    van Zomeren, Paul; Hoogvorst, A.; Coenegracht, P.M J; de Jong, G.J.

    2004-01-01

    An automated method for the optimisation of high-performance liquid chromatography is developed. First of all, the sample of interest is analysed with various eluent compositions. All obtained data are combined into one augmented data matrix. Subsequently, augmented iterative target transformation