Rapid on-site sensing aflatoxin B1 in food and feed via a chromatographic time-resolved fluoroimmunoassay.

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Zhaowei Zhang

Full Text Available Aflatoxin B1 poses grave threats to food and feed safety due to its strong carcinogenesis and toxicity, thus requiring ultrasensitive rapid on-site determination. Herein, a portable immunosensor based on chromatographic time-resolved fluoroimmunoassay was developed for sensitive and on-site determination of aflatoxin B1 in food and feed samples. Chromatographic time-resolved fluoroimmunoassay offered a magnified positive signal and low signal-to-noise ratio in time-resolved mode due to the absence of noise interference caused by excitation light sources. Compared with the immunosensing performance in previous studies, this platform demonstrated a wider dynamic range of 0.2-60 μg/kg, lower limit of detection from 0.06 to 0.12 µg/kg, and considerable recovery from 80.5% to 116.7% for different food and feed sample matrices. It was found to be little cross-reactivity with other aflatoxins (B2, G1, G2, and M1. In the case of determination of aflatoxin B1 in peanuts, corn, soy sauce, vegetable oil, and mouse feed, excellent agreement was found when compared with aflatoxin B1 determination via the conversational high-performance liquid chromatography method. The chromatographic time-resolved fluoroimmunoassay affords a powerful alternative for rapid on-site determination of aflatoxin B1 and holds a promise for food safety in consideration of practical food safety and environmental monitoring.

Rapid on-site sensing aflatoxin B1 in food and feed via a chromatographic time-resolved fluoroimmunoassay.

Science.gov (United States)

Zhang, Zhaowei; Tang, Xiaoqian; Wang, Du; Zhang, Qi; Li, Peiwu; Ding, Xiaoxia

2015-01-01

Aflatoxin B1 poses grave threats to food and feed safety due to its strong carcinogenesis and toxicity, thus requiring ultrasensitive rapid on-site determination. Herein, a portable immunosensor based on chromatographic time-resolved fluoroimmunoassay was developed for sensitive and on-site determination of aflatoxin B1 in food and feed samples. Chromatographic time-resolved fluoroimmunoassay offered a magnified positive signal and low signal-to-noise ratio in time-resolved mode due to the absence of noise interference caused by excitation light sources. Compared with the immunosensing performance in previous studies, this platform demonstrated a wider dynamic range of 0.2-60 μg/kg, lower limit of detection from 0.06 to 0.12 µg/kg, and considerable recovery from 80.5% to 116.7% for different food and feed sample matrices. It was found to be little cross-reactivity with other aflatoxins (B2, G1, G2, and M1). In the case of determination of aflatoxin B1 in peanuts, corn, soy sauce, vegetable oil, and mouse feed, excellent agreement was found when compared with aflatoxin B1 determination via the conversational high-performance liquid chromatography method. The chromatographic time-resolved fluoroimmunoassay affords a powerful alternative for rapid on-site determination of aflatoxin B1 and holds a promise for food safety in consideration of practical food safety and environmental monitoring.

Simultaneous derivatisation and preconcentration of parabens in food and other matrices by isobutyl chloroformate and dispersive liquid-liquid microextraction followed by gas chromatographic analysis.

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Jain, Rajeev; Mudiam, Mohana Krishna Reddy; Chauhan, Abhishek; Ch, Ratnasekhar; Murthy, R C; Khan, Haider A

2013-11-01

A simple, rapid and economical method has been proposed for the quantitative determination of parabens (methyl, ethyl, propyl and butyl paraben) in different samples (food, cosmetics and water) based on isobutyl chloroformate (IBCF) derivatisation and preconcentration using dispersive liquid-liquid microextraction in single step. Under optimum conditions, solid samples were extracted with ethanol (disperser solvent) and 200 μL of this extract along with 50 μL of chloroform (extraction solvent) and 10 μL of IBCF was rapidly injected into 2 mL of ultra-pure water containing 150 μL of pyridine to induce formation of a cloudy state. After centrifugation, 1 μL of the sedimented phase was analysed using gas chromatograph-flame ionisation detector (GC-FID) and the peaks were confirmed using gas chromatograph-positive chemical ionisation-mass spectrometer (GC-PCI-MS). Method was found to be linear over the range of 0.1-10 μg mL(-1) with square of correlation coefficient (R(2)) in the range of 0.9913-0.9992. Limit of detection (LOD) and limit of quantification (LOQ) were found to be 0.029-0.102 μg mL(-1) and 0.095-0.336 μg mL(-1) with a signal to noise ratio of 3:1 and 10:1, respectively. Copyright © 2013 Elsevier Ltd. All rights reserved.

Determination of trihalomethanes in waters by ionic liquid-based single drop microextraction/gas chromatographic/mass spectrometry.

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Aguilera-Herrador, Eva; Lucena, Rafael; Cárdenas, Soledad; Valcárcel, Miguel

2008-10-31

A simple, rapid, solventless method for the determination of trihalomethanes (THMs) (chloroform, bromodichloromethane, dibromochloromethane and bromoform) in water samples is presented. The analytes are extracted from the headspace of the aqueous matrix into a 2 microL drop of the ionic liquid 1-octyl-3-methyl-imidazolium hexafluorophosphate working at 30 degrees C for 30 min. The separation and detection of the target compounds is accomplished by gas chromatography/mass spectrometry owing to the use of an interface that efficiently transfers the analytes extracted in the ionic liquid drop to the gas chromatograph while preventing the ionic liquid from entering the column. The detection limits obtained are below the values compelled by the legislation, ranging from 0.5 microg L(-1) for chloroform and bromodichloromethane to 0.9 microg L(-1) for dibromochloromethane. The use of ionic liquid in the extraction procedure avoids the use of organic solvents and leads to relative standard deviations that range from 3.1% to 4.8%.

Liquid chromatographic determination of sennosides in Cassia angustifolia leaves.

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Srivastava, Alpuna; Pandey, Richa; Verma, Ram K; Gupta, Madan M

2006-01-01

A simple liquid chromatographic method was developed for the determination of sennosides B and A in leaves of Cassia angustifolia. These compounds were extracted from leaves with a mixture of methanol-water (70 + 30, v/v) after defatting with hexane. Analyte separation and quantitation were achieved by gradient reversed-phase liquid chromatography and UV absorbance at 270 nm using a photodiode array detector. The method involves the use of an RP-18 Lichrocart reversed-phase column (5 microm, 125 x 4.0 mm id) and a binary gradient mobile-phase profile. The various other aspects of analysis, namely, peak purity, similarity, recovery, repeatability, and robustness, were validated. Average recoveries of 98.5 and 98.6%, with a coefficient of variation of 0.8 and 0.3%, were obtained by spiking sample solution with 3 different concentration solutions of standards (60, 100, and 200 microg/mL). Detection limits were 10 microg/mL for sennoside B and 35 microg/mL for sennoside A, present in the sample solution. The quantitation limits were 28 and 100 microg/mL. The analytical method was applied to a large number of senna leaf samples. The new method provides a reliable tool for rapid screening of C. angustifolia samples in large numbers, which is needed in breeding/genetic engineering and genetic mapping experiments.

Liquid chromatographic determination with fluorescence detection of B6 vitamers and riboflavin in milk and pharmaceuticals

International Nuclear Information System (INIS)

Gatti, R.; Gioia, M.G.

2005-01-01

A simple, reliable and selective high performance liquid chromatographic method with fluorescence detection at different programmed wavelengths has been developed for the simultaneous analysis of B 6 vitamers (pyridoxal 5'-phosphate, 4-pyridoxic acid, pyridoxal, pyridoxine and pyridoxamine) and Vitamin B 2 in commercial vitaminized milk and in woman milk. The chromatographic separations were performed on a reversed phase octyl column by using a mobile phase consisting of sodium pentanesulfonate in 1% acetic acid-methanol-tetrahydrofuran under gradient elution conditions. The fluorescence intensity of pyridoxal 5'-phosphate was enhanced by post-column photochemical conversion, giving significantly different fluorescence spectra by a on-line photoreactor switched OFF and ON under irradiation at 254 nm. In addition, a simple and rapid method in isocratic conditions without the need of photochemical conversion was proposed for the analysis of Vitamin B 6 and Vitamin B 2 in pharmaceuticals. Linearity, precision, recovery, selectivity and sensitivity were found satisfactory for each analysed compound. Quantitation limits ranged from 26 to 240 fmol

The development of a high performance liquid chromatograph with a sensitive on-stream radioactivity monitor for the analysis of 3H- and 14C-labelled gibberellins

International Nuclear Information System (INIS)

Reeve, D.R.; Yokota, T.; Nash, L.; Crozier, A.

1976-01-01

The development of a high performance liquid chromatograph for the separation of gibberellins is described. The system combines high efficiency, peak capacity, and sample capacity with rapid speed of analysis. In addition, the construction details of a sensitive on-stream radioactivity monitor are outlined. The overall versatility of the chromatograph has been demonstrated by the separation of a range of 3 H- and 14 C-labelled gibberellins and gibberellin precursors. The system also has considerable potential for the analysis of abscisic acid and acidic and neutral indoles. (author)

Development of Direct Reversed-Phase High Performance liquid chromatographic method for quantitative determination of gabapentin in pharmaceutical dosage

International Nuclear Information System (INIS)

Hassan, W.; Zaman, B.; Rahman, S.; Rahman, A.U.; Ali, N.; Mohammadzai, I.U.

2012-01-01

The objective of the present work was to develop and validate a rapid analytical method for quantitative determination of Gabapentin in pharmaceutical dosage tablets and capsules. An accurate, simple, and sensitive reversed-phase high performance liquid chromatographic (HPLC) method, UV detection at 215 nm and flow rate at 1.0 ml/min has been developed. Isocratic elution was used instead of gradient elution to reduce the time and cost of serial analysis. The mobile phase was a mixture of water and methanol (HPLC grade). The retention time (Rt) of Gabapentin was 4.681 +- 0.013 minutes. Recovery, Precision, accuracy, and linearity were determined for the stated method. The calibration curve was linear and the correlation coefficient was 0.9996. There was no chromatographic interference from other excipients present in dosage form. The method was validated appropriately and successfully used for determination of Gabapentin in Pharmaceutical formulations. (author)

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

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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.

Stereospecific high-performance liquid chromatographic assay of sotalol in plasma.

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Carr, R A; Foster, R T; Bhanji, N H

1991-09-01

A convenient high-performance liquid chromatographic (HPLC) assay was developed for determination of sotalol (STL) enantiomers in plasma. Following addition of the internal standard (IS; racemic atenolol), enantiomers of STL and IS were extracted using ethyl acetate. After evaporation of the organic layer, samples were derivatized with a solution of S-(+)-1-(1-naphthyl)ethyl isocyanate (NEIC). The resulting diastereomers were chromatographed with normal-phase HPLC with chloroform:hexane:methanol [65:33:2 (v/v)] as the mobile phase at a flow rate of 2 ml/min. The fluorescence detection wavelength was set at 220 nm for excitation with no emission filter. The suitability of the assay for pharmacokinetic studies was determined by measuring STL enantiomers in the plasma of a healthy subject after administration of a single 160-mg oral, racemic dose of STL.

The combination of the liquid chromatograph with the nuclear magnetic resonance spectrometer

International Nuclear Information System (INIS)

Scott, R.P.W.

1986-01-01

The association of the liquid chromatograph with the NMR spectrometer would be a very powerful analytical system for the separation and identification of unknown mixtures. There are, however, some serious difficulties involved with the association of these two techniques. The historical development of NMR chromatography is outlined and some problems are discussed. (Auth.)

Comparison of core-shell and totally porous ultra high performance liquid chromatographic stationary phases based on their selectivity towards alfuzosin compounds.

Science.gov (United States)

Szulfer, Jarosław; Plenis, Alina; Bączek, Tomasz

2014-06-13

This paper focuses on the application of a column classification system based on the Katholieke Universiteit Leuven for the characterization of physicochemical properties of core-shell and ultra-high performance liquid chromatographic stationary phases, followed by the verification of the reliability of the obtained column classification in pharmaceutical practice. In the study, 7 stationary phases produced in core-shell technology and 18 ultra-high performance liquid chromatographic columns were chromatographically tested, and ranking lists were built on the FKUL-values calculated against two selected reference columns. In the column performance test, an analysis of alfuzosin in the presence of related substances was carried out using the brands of the stationary phases with the highest ranking positions. Next, a system suitability test as described by the European Pharmacopoeia monograph was performed. Moreover, a study was also performed to achieve a purposeful shortening of the analysis time of the compounds of interest using the selected stationary phases. Finally, it was checked whether methods using core-shell and ultra-high performance liquid chromatographic columns can be an interesting alternative to the high-performance liquid chromatographic method for the analysis of alfuzosin in pharmaceutical practice. Copyright © 2014 Elsevier B.V. All rights reserved.

High-performance liquid chromatographic method for guanylhydrazone compounds.

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Cerami, C; Zhang, X; Ulrich, P; Bianchi, M; Tracey, K J; Berger, B J

1996-01-12

A high-performance liquid chromatographic method has been developed for a series of aromatic guanylhydrazones that have demonstrated therapeutic potential as anti-inflammatory agents. The compounds were separated using octadecyl or diisopropyloctyl reversed-phase columns, with an acetonitrile gradient in water containing heptane sulfonate, tetramethylammonium chloride, and phosphoric acid. The method was used to reliably quantify levels of analyte as low as 785 ng/ml, and the detector response was linear to at least 50 micrograms/ml using a 100 microliters injection volume. The assay system was used to determine the basic pharmacokinetics of a lead compound, CNI-1493, from serum concentrations following a single intravenous injection in rats.

Gas-liquid chromatographic determination of resmethrin in corn, cornmeal, flour, and wheat.

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Simonaitis, R A; Cail, R S

1975-09-01

A gas-liquid chromatographic (GLC) method was developed for the determination of residues of resmethrin ((5-benzyl-3-furyl)methyl cis-trans-(+/-)-2,2-dimethyl-3-(2-methylpropenyl)-cyclopropanecarboxylate) in corn, cornmeal, flour, and wheat. The commodity, fortified with resmethrin, was extracted by tumbling with pentane and transferred to acetonitrile, the fat was partitioned off, and the sample was chromatographed with 3% ethyl acetate in pentane on Florisil containing 0.5% water. The resmethrin residue was determined by GLC with a flame ionization detector. The results were compared with known standards that had undergone the same cleanup procedures. The method was sensitive to concentrations of resmethrin to 0.2 ppm, recoveries averaged 83%, and reproducibility was good.

Storing of Extracts in Polypropylene Microcentrifuge Tubes Yields Contaminant Peak During Ultra-flow Liquid Chromatographic Analysis.

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Kshirsagar, Parthraj R; Hegde, Harsha; Pai, Sandeep R

2016-05-01

This study was designed to understand the effect of storage in polypropylene microcentrifuge tubes and glass vials during ultra-flow liquid chromatographic (UFLC) analysis. One ml of methanol was placed in polypropylene microcentrifuge tubes (PP material, Autoclavable) and glass vials (Borosilicate) separately for 1, 2, 4, 8, 10, 20, 40, and 80 days intervals stored at -4°C. Contaminant peak was detected in methanol stored in polypropylene microcentrifuge tubes using UFLC analysis. The contaminant peak detected was prominent, sharp detectable at 9.176 ± 0.138 min on a Waters 250-4.6 mm, 4 μ, Nova-Pak C18 column with mobile phase consisting of methanol:water (70:30). It was evident from the study that long-term storage of biological samples prepared using methanol in polypropylene microcentrifuge tubes produce contaminant peak. Further, this may mislead in future reporting an unnatural compound by researchers. Long-term storage of biological samples prepared using methanol in polypropylene microcentrifuge tubes produce contaminant peakContamination peak with higher area under the curve (609993) was obtained in ultra-flow liquid chromatographic run for methanol stored in PP microcentrifuge tubesContamination peak was detected at retention time 9.113 min with a lambda max of 220.38 nm and 300 mAU intensity on the given chromatographic conditionsGlass vials serve better option over PP microcentrifuge tubes for storing biological samples. Abbreviations used: UFLC: Ultra Flow Liquid Chromatography; LC: Liquid Chromatography; MS: Mass spectrometry; AUC: Area Under Curve.

Liquid chromatographic and spectrophotometric methods for the determination of erythromycin stearate and trimethoprim in tablets

OpenAIRE

Hassib, Sonia T.; Farag, Awatef E.; Elkady, Ehab F.

2011-01-01

Simple, accurate and precise reversed-phase liquid chromatographic (LC) and spectrophotometric methods have been developed and validated for the determination of erythromycin stearate (ERS) and trimethoprim (TMP) in mixture. In LC method, chromatographic separation was achieved on a Symmetry® Waters C18 column (150 × 4.6 mm, 5 μm) based on isocratic elution using a mobile phase consisting of potassium dihydrogen phosphate buffer pH (9):acetonitrile:water (25:100:50, v/v/v) at a flow rate of 1...

Liquid chromatographic separation of terpenoid pigments in foods and food products.

Science.gov (United States)

Cserháti, T; Forgács, E

2001-11-30

The newest achievements in the use of various liquid chromatographic techniques such as adsorption and reversed-phase thin-layer chromatography and HPLC employed for the separation and quantitative determination of terpenoid-based color substances in foods and food products are reviewed. The techniques applied for the analysis of individual pigments and pigments classes are surveyed and critically evaluated. Future trends in the separation and identification of pigments in foods and food products are delineated.

Liquid chromatographic determination of pioglitazone in pharmaceuticals, serum and urine samples

International Nuclear Information System (INIS)

Abro, K.; Memon, N.; Bhanger, M.I.; Mahesar, S.A.; Parveen, S.

2011-01-01

A rapid and reliable analytical method based on high-performance liquid chromatography (HPLC) with UV detection (221 nm) has been developed for the determination of the anti-hyper glycemic agent Pioglitazone in pharmaceutical formulations and biological fluids (serum and urine) after clean-up with solid-phase extraction. Chromatographic separation was achieved with a Chromolith Performance RP-18e (10 4.6mm) column using mobile phase composition of acetonitrile: mixed phosphate buffer (pH 2.5; 10mM) (30:70, v/v) with a flow rate of 2.0mL/min. The total run time was 2 min. under optimized conditions. The calibration curve was found to be linear in the range of 1-10 mu g mL/sup -1/ with regression coefficient of 0.9996, and the lower limit of detection 72 ng/20 mu L injection. The method has been validated for the system suitability, linearity, precision and accuracy, limits of detection, specificity, stability and robustness. The %recovery of Pioglitazone in pharmaceutical formulations was found to be 104.7%. The assay has been applied successfully to the pharmaceutical Tablet samples and biological fluids (serum and urine) of healthy volunteers. (author)

High-performance liquid chromatographic quantitation of desmosine plus isodesmosine in elastin and whole tissue hydrolysates

International Nuclear Information System (INIS)

Soskel, N.T.

1987-01-01

Quantitation of desmosine and isodesmosine, the major crosslinks in elastin, has been of interest because of their uniqueness and use as markers of that protein. Accurate measurement of these crosslinks may allow determination of elastin degradation in vivo and elastin content in tissues, obviating lengthy extraction procedures. We have developed a method of quantitating desmosine plus isodesmosine in hydrolysates of tissue and insoluble elastin using high-performance liquid chromatographic separation and absorbance detection that is rapid (21-35 min) and sensitive (accurate linearity from 100 pmol to 5 nmol). This method has been used to quantitate desmosines in elastin from bovine nuchal ligament and lung and in whole aorta from hamsters. The ability to completely separate [ 3 H]lysine from desmosine plus isodesmosine allows the method to be used to study incorporation of lysine into crosslinks in elastin

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...

Rapid determination of ampicillin in bovine milk by liquid chromatography with fluorescence detection

Energy Technology Data Exchange (ETDEWEB)

Ang, C.Y.W.; Luo, Wenhong [National Center for Toxicological Research, Jefferson, AR (United States)

1997-01-01

A rapid and sensitive liquid chromatographic (LC) method was developed for the determination of ampicillin residues in raw bovine milk, processed skim milk, and pasteurized, homogenized whole milk with vitamin D. Milk samples were deproteinized with trichloroacetic acid (TCA) and acetonictrile. After centrifugation, the clear supernatant was reacted with formaldehyde and TCA under heat. The major fluorescent derivative of ampicillin was then determined by reversed-phase LC with fluorescence detection. Average recoveries of ampicillin fortified at 5, 10, and 20 ppb (ng/mL) were all >85% with coefficients of variation <10%. Limits of detection ranged from 0.31 to 0.51 ppb and limits of quantitation, from 0.66 to 1.2 ppb. After appropriate validation, this method should be suitable for rapid analysis of milk for ampicillin residues at the tolerance level of 10 ppb. 16 refs., 4 figs., 3 tabs.

Development and evaluation of a gas chromatographic method for the determination of triazine herbicides in natural water samples

Science.gov (United States)

Steinheimer, T.R.; Brooks, M.G.

1984-01-01

A multi-residue method is described for the determination of triazine herbicides in natural water samples. The technique uses solvent extraction followed by gas chromatographic separation and detection employing nitrogen-selective devices. Seven compounds can be determined simultaneously at a nominal detection limit of 0.1 ??g/L in a 1-litre sample. Three different natural water samples were used for error analysis via evaluation of recovery efficiencies and estimation of overall method precision. As an alternative to liquid-liquid partition (solvent extraction) for removal of compounds of interest from water, solid-phase extraction (SPE) techniques employing chromatographic grade silicas with chemically modified surfaces have been examined. SPE is found to provide rapid and efficient concentration with quantitative recovery of some triazine herbicides from natural water samples. Concentration factors of 500 to 1000 times are obtained readily by the SPE technique.A multi-residue method is described for the determination of triazine herbicides in natural water samples. The technique uses solvent extraction followed by gas chromatographic separation and detection employing nitrogen-selective devices. Seven compounds can be determined simultaneously at a nominal detection limit of 0. 1 mu g/L in a 1-litre sample. As an alternative to liquid-liquid partition (solvent extraction) for removal of compounds of interest from water, solid-phase extraction (SPE) techniques employing chromatographic grade silicas with chemically modified surfaces have been examined. SPE is found to provide rapid and efficient concentration with quantitative recovery of some triazine herbicides from natural water samples. Concentration factors of 500 to 1000 times are obtained readily by the SPE technique.

Liquid chromatographic determination of saccharin in beverages and desserts: complementary collaborative study.

Science.gov (United States)

Sjöberg, A M

1988-01-01

A complementary collaborative study was conducted on a liquid chromatographic method for determination of saccharin in accordance with the latest international recommendations. One industrial and 6 official food control laboratories analyzed 3 samples of a juice, a soft drink, and a dessert at concentration levels of 26-90 mg/L, 33-73 mg/L, and 56-147 mg/kg, respectively. Blind duplicates and a blank were supplied for each type of material at each concentration level. The beverage was chromatographed directly and the dessert was extracted with ethanol before chromatography. Average recoveries were 95-107%. The reproducibility relative standard deviations were 6.4-7.3% for the juice, 9.2-20.6% for the soft drink, and 13.4-16.2% for the dessert. The outlier percentage was 14.3%. The results were compared with those of an earlier collaborative study by Nordic laboratories and with general collaborative results obtained by AOAC.

Sorption and chromatographic techniques for processing liquid waste of nuclear fuel cycle

International Nuclear Information System (INIS)

Gelis, V.M.; Milyutin, V.V.; Chuveleva, E.A.; Maslova, G.B.; Kudryavtseva, S.P.; Firsova, L.A.; Kozlitin, E.A.

2000-01-01

In the spent nuclear fuel processing procedures the significant quantity of high level liquid waste containing long-lived high toxic radionuclides of cesium, strontium, promethium, americium, curium, etc. is generated. Separation of those radionuclides from the waste not merely simplifies the further safe waste handling but also reduces the waste processing operation costs due to the market value of certain individual radionuclide preparations. Recovery and separation of high grade pure long-lived radionuclide preparations is frequently performed by means of chromatographic techniques. (authors)

Chemometric strategy for automatic chromatographic peak detection and background drift correction in chromatographic data.

Science.gov (United States)

Yu, Yong-Jie; Xia, Qiao-Ling; Wang, Sheng; Wang, Bing; Xie, Fu-Wei; Zhang, Xiao-Bing; Ma, Yun-Ming; Wu, Hai-Long

2014-09-12

Peak detection and background drift correction (BDC) are the key stages in using chemometric methods to analyze chromatographic fingerprints of complex samples. This study developed a novel chemometric strategy for simultaneous automatic chromatographic peak detection and BDC. A robust statistical method was used for intelligent estimation of instrumental noise level coupled with first-order derivative of chromatographic signal to automatically extract chromatographic peaks in the data. A local curve-fitting strategy was then employed for BDC. Simulated and real liquid chromatographic data were designed with various kinds of background drift and degree of overlapped chromatographic peaks to verify the performance of the proposed strategy. The underlying chromatographic peaks can be automatically detected and reasonably integrated by this strategy. Meanwhile, chromatograms with BDC can be precisely obtained. The proposed method was used to analyze a complex gas chromatography dataset that monitored quality changes in plant extracts during storage procedure. Copyright © 2014 Elsevier B.V. All rights reserved.

Characterization of crude oils and petroleum products: (I Elution liquid chromatographic separation and gas chromatographic analysis of crude oils and petroleum products

Directory of Open Access Journals (Sweden)

E.O. Odebunmi

2002-12-01

Full Text Available Some physical and chemical properties of samples of light, medium and heavy Nigerian crude oils and petroleum products including gasoline, kerosene and engine oil have been measured and are reported in this paper. The crude oils and petroleum products have also been characterized by fractional distillation and elution liquid chromatography. The fractions obtained from elution liquid chromatography were analyzed using gas chromatography (GC. The GC fractions were identified by comparing the retention time of peaks in the unknown samples with those of components of calibration standard mixtures. The importance of the physico-chemical properties and the significance of the fractional distillation and chromatographic separation methods to industrial process operations have been discussed.

Direct chromatographic methods for the rapid determination of homogentisic acid in strawberry tree (Arbutus unedo L.) honey.

Science.gov (United States)

Scanu, Roberta; Spano, Nadia; Panzanelli, Angelo; Pilo, Maria I; Piu, Paola C; Sanna, Gavino; Tapparo, Andrea

2005-10-07

Two rapid and direct chromatographic methods based on reverse phase-high performance liquid chromatography (RP-HPLC) and ion chromatography (IC) were developed for the determination of homogentisic acid (HA) in honey. This is the marker of the botanic origin of strawberry tree honey. The methods were validated and tested using 22 samples from Sardinia, Italy. The IC method is faster than the RP-HPLC one (6 min versus 13 min of total run), but it is slightly less sensitive (the limit of detection (LOD), is 26 mg kg(-1) versus 15 mg kg(-1)) and reproducible (relative standard deviation, RSD, of 10.4 and 4.4%, respectively). The whole dataset of validation parameters allows both the proposed methods to be considered as bias-free (by recovery tests, comparison of analytical results of the two independent methods and analysis of a synthetic sample) and precise (both the techniques show a repeatability better than 2% repeatability in the range between 70 and 600 mg kg(-1)).

Study and ICH validation of a reverse-phase liquid chromatographic method for the quantification of the intact monoclonal antibody cetuximab

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Antonio Martínez-Ortega

2016-04-01

Full Text Available Cetuximab (CTX is a potent chimeric mouse/human monoclonal antibody (mAb approved worldwide for treatment of metastatic colorectal cancer. Among the various biological and physical analyses performed for full study on this biopharmaceutic, the determination of the concentration preparations throughout manufacturing and subsequent handling in hospital is particularly relevant. In the present work, the study and validation of a method for quantifying intact CTX by reverse-phase high-performance liquid chromatography with diode array detection ((RPHPLC/DAD is presented. With that end, we checked the performance of a chromatographic method for quantifying CTX and conducted a study to validate the method as stability-indicating in accordance with the International Conference on Harmonization guidelines (ICH for biotechnological drugs; therefore, we evaluated linearity, accuracy, precision, detection and quantification limits, robustness and system suitability. The specificity of the method and the robustness of the mAb formulation against external stress factors were estimated by comprehensive chromatographic analysis by subjecting CTX to several informative stress conditions. As demonstrated, the method is rapid, accurate, and reproducible for CTX quantification. It was also successfully used to quantify CTX in a long-term stability study performed under hospital conditions.

Liquid chromatographic method for determining the concentration of bisazir in water

Science.gov (United States)

Scholefield, Ronald J.; Slaght, Karen S.; Allen, John L.

1997-01-01

Barrier dams, traps, and lampricides are the techniques currently used by the Great Lakes Fishery Commission to control sea lampreys (Petromyzon marinus) in the Great Lakes. To augment these control techniques, a sterile-male-release research program was initiated at the Lake Huron Biological Station. Male sea lampreys were sterilized by intraperitoneal injection of the chemical sterilant P,P-bis(1-aziridinyl)-N-methylphosphinothioic amide (bisazir). An analytical method was needed to quantitate the concentration of bisazir in water and to routinely verify that bisazir (>25 μg/L) does not persist in the treated effluent discharged from the sterilization facility to Lake Huron. A rapid, accurate, and sensitive liquid chromatographic (LC) method was developed for determining bisazir in water. Bisazir was dissolved in Lake Huron water; extracted and concentrated on a C18 solid-phase extraction column; eluted with methanol; and quantitated by reversed-phase LC using a C18 column, a mobile phase of 70% water and 30% methanol (v/v), and UV detection (205 nm). Bisazir retention time was 7-8 min; total run time was about 20 min. Method detection limit for bisazir dissolved in Lake Huron water was about 15 μg/L. Recovery from Lake Huron water fortified with bisazir at 100 μg/L was 94% (95% confidence interval, 90.2-98.2%).

Core-shell in liquid chromatography: application for determining sulphonamides in feed and meat using conventional chromatographic systems

Directory of Open Access Journals (Sweden)

Antonio Armentano

2016-12-01

Full Text Available A C18 column packed with core-shell particles was used for the chromatographic separation of sulphonamides in feed and meat by a conventional high performance liquid chromatography system coupled with a diode array detector. Two analytical methods, already used in our laboratory, have been modified without any changes in the extraction and clean-up steps and in the liquid chromatography instrumentation. Chromatographic conditions applied on a traditional 5-μm column have been optimized on a column packed with 2.6 μm core-shell particles. A binary mobile phase [acetate buffer solution at pH 4.50 and a mixture of methanol acetonitrile 50: 50 (v/v] was employed in gradient mode at the flow rate of 1.2 mL with an injection volume of 6 μL. These chromatographic conditions allow the separation of 13 sulphonamides with an entire run of 13 minutes. Preliminary studies have been carried out comparing blanks and spiked samples of feed and meat. A good resolution and the absence of interferences were achieved in chromatograms for both matrices. Since no change was made to the sample preparation, the optimized method does not require a complete revalidation and can be used to make routine analysis faster.

Liquid chromatographic separation of zalcitabine and its stereoisomers.

Science.gov (United States)

Scypinski, S; Ross, A J

1994-10-01

A liquid chromatographic method capable of separating and quantitating the stereoisomers of zalcitabine has been developed and validated. The separation was achieved with an Astec Cyclobond I--RSP column and a mobile phase of 0.25% triethylamine in water adjusted to a pH of 6.5 with glacial acetic acid. All enantiomers were found to exhibit a linear response in the range of 0.1-10% in the presence of 100% zalcitabine. Precision of analysis was found to be less than 1.5% at a level of 1% relative to zalcitabine. The limit of detection for two of the three enantiomeric impurities was determined to be 0.05% relative to zalcitabine. The detection limit for the third was found to be 0.1%. This method was successfully applied to the analysis of reference standards and several production scale batches. All of these materials were found to be stereochemically pure to a level of 99.8% or better.

Development and validation of micellar liquid chromatographic methods for the determination of antibiotics in different matrixes.

Science.gov (United States)

Rambla-Alegre, Maria; Esteve-Romero, Josep; Carda-Broch, Samuel

2011-01-01

Antibiotics are the most important bioactive and chemotherapeutic compounds to be produced by microbiological synthesis, and they have proved their worth in a variety of fields, such as medicinal chemistry, agriculture, and the food industry. Interest in antibiotics has grown in parallel with an increasingly high degree of productivity in the field of analytical applications. Therefore, it is necessary to develop chromatographic procedures capable of determining various drugs simultaneously in the shortest possible time. Micellar liquid chromatography (MLC) is an RP-HPLC technique that offers advantages over conventional HPLC as far as sample preparation, selectivity, and versatility are concerned. Its main advantage is that samples can be injected directly into the chromatographic system with no previous preparation step. This paper mainly focuses on the results of the authors' own recent research and reports the chromatographic conditions for determination of various antibiotics (penicillins, quinolones, and sulfonamides) in different matrixes (pharmaceuticals, biological fluids, and food). The work of other authors on MLC-based antibiotic determination has been included.

Development and Validation of Liquid Chromatographic Method for Estimation of Naringin in Nanoformulation

Directory of Open Access Journals (Sweden)

Kranti P. Musmade

2014-01-01

Full Text Available A simple, precise, accurate, rapid, and sensitive reverse phase high performance liquid chromatography (RP-HPLC method with UV detection has been developed and validated for quantification of naringin (NAR in novel pharmaceutical formulation. NAR is a polyphenolic flavonoid present in most of the citrus plants having variety of pharmacological activities. Method optimization was carried out by considering the various parameters such as effect of pH and column. The analyte was separated by employing a C18 (250.0 × 4.6 mm, 5 μm column at ambient temperature in isocratic conditions using phosphate buffer pH 3.5: acetonitrile (75 : 25% v/v as mobile phase pumped at a flow rate of 1.0 mL/min. UV detection was carried out at 282 nm. The developed method was validated according to ICH guidelines Q2(R1. The method was found to be precise and accurate on statistical evaluation with a linearity range of 0.1 to 20.0 μg/mL for NAR. The intra- and interday precision studies showed good reproducibility with coefficients of variation (CV less than 1.0%. The mean recovery of NAR was found to be 99.33 ± 0.16%. The proposed method was found to be highly accurate, sensitive, and robust. The proposed liquid chromatographic method was successfully employed for the routine analysis of said compound in developed novel nanopharmaceuticals. The presence of excipients did not show any interference on the determination of NAR, indicating method specificity.

Improved Chromatographic Bioavailability Estimations

National Research Council Canada - National Science Library

Dorsey, John

1996-01-01

.... Since the inception of reversed phase liquid chromatography there have been many attempts to correlate chromatographic retention with bioavailability and the most often used bulk measure, the octanol...

Direct coupling of a liquid chromatograph to a continuous flow hydrogen nuclear magnetic resonance detector for analysis of petroleum and synthetic fuels

International Nuclear Information System (INIS)

Haw, J.F.; Glass, T.E.; Hausler, D.W.; Motell, E.; Dorn, H.C.

1980-01-01

Initial results obtained for a flow 1 H nuclear magnetic resonance (NMR) detector directly coupled to a liquid chromatography unit are described. Results achieved for a model mixture and several jet fuel samples are discussed. Chromatographic separation of alkanes, alkylbenzenes, and substituted naphthalenes present in the jet fuel samples are easily identified with the 1 H NMR detector. Results with our present flow 1 H NMR insert indicate that 5-Hz linewidths are readily obtainable for typical chromatographic flow rates. The limitations and advantages of this liquid chromatography detector are compared with more commonly employed detectors (e.g., refractive index detectors). 11 figures

Abnormal tyrosine and phenylalanine metabolism in patients with tyrosyluria and phenylketonuria; gas-liquid chromatographic analysis of urinary metabolites

NARCIS (Netherlands)

Wadman, S.K.; Heiden, C. van der; Ketting, D.; Sprang, F.J. van

Gas-liquid chromatographic methods have been developed for the analysis of: urinary phenylalanine metabolites (I) in patients with phenylketonuria, tyrosine metabolites (II) in patients with a disturbed tyrosine metabolism at the level of p-hydroxyphenylpyruvate hydroxylase, and homogentisic acid in

Chromatographic separations of stereoisomers

Energy Technology Data Exchange (ETDEWEB)

Souter, R.W.

1985-01-01

This text covers both diastereomers and enantiomers; describes techniques for GC, HPLC, and other chromatographic methods; and tabulates results of various applications by both techniques and compound class. It provides current knowledge about separation mechanisms and interactions of asymmetric molecules, as well as experimental and commercial materials such as columns, instruments, and derivatization reagents. The contents also include stereoisomer separations by gas chromatography. Stereoisomer separations by high-performance liquid chromatography. Stereoisomer separations by other chromatographic techniques.

HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHIC PROFILING OF TRYPTOPHAN AND RELATED INDOLES IN BODY-FLUIDS AND TISSUES OF CARCINOID PATIENTS

NARCIS (Netherlands)

KEMA, IP; SCHELLINGS, AMJ; HOPPENBROUWERS, CJM; RUTGERS, HM; DEVRIES, EGE; MUSKIET, FAJ

1993-01-01

A high performance liquid chromatographic method with quaternary gradient elution and fluorometric detection was developed for profiling of tryptophan (TRP), 5-hydroxytryptophan, serotonin (5-HT) and 5-hydroxyindole-3-acetic acid (5-HIAA) in urine, platelet-rich plasma and (tumour) tissue of

[Determination of phthalate plasticizers in foods by high performance liquid chromatography with gel permeation chromatographic clean-up].

Science.gov (United States)

Zhang, Chunyu; Wang, Hui; Zhang, Xiaohui; Ma, Zhongqiang; Deng, Wanmei; Hu, Ke; Ding, Mingyu

2011-12-01

A method of gel permeation chromatography-high performance liquid chromatography (GPC-HPLC) was established for the simultaneous determination of 5 main phthalate plasticizers in foods (edible oil, instant noodles, fried pastries, Saqima, etc.). The samples were extracted with petroleum ether in an ultrasonator, purified by a GPC column, and analyzed by HPLC. The chromatographic separation was achieved on a Labtech-C18 column (250 mm x 4.6 mm, 5 microm) using acetonitrile and water mixture as the mobile phases in a gradient elution mode. The developed method exhibited a linear correlation coefficient of more than 0.997 and the detection limits of 3.25 - 13.4 microg/L. The spike recoveries were between 70.4% and 113.6% with the relative standard deviations (RSDs, n = 3) of 0.3% - 5.8% at the spiked level of 50 mg/L. This method is simple, rapid and practical, and can be used for the simultaneous determination of PAEs in grease food samples.

Characterizing the selectivity of stationary phases and organic modifiers in reversed-phase high-performance liquid chromatographic systems by a general solvation equation using gradient elution.

Science.gov (United States)

Du, C M; Valko, K; Bevan, C; Reynolds, D; Abraham, M H

2000-11-01

Retention data for a set of 69 compounds using rapid gradient elution are obtained on a wide range of reversed-phase stationary phases and organic modifiers. The chromatographic stationary phases studied are Inertsil (IN)-ODS, pentafluorophenyl, fluoro-octyl, n-propylcyano, Polymer (PLRP-S 100), and hexylphenyl. The organic solvent modifiers are 2,2,2-trifluoroethanol (TFE); 1,1,1,3,3,3-hexafluoropropan-2-ol (HFIP); isopropanol; methanol (MeOH); acetonitrile (AcN); tetrahydrofuran; 1,4-dioxane; N,N-dimethylformamide; and mixed solvents of dimethylsulfoxide (DMSO) with AcN and DMSO with MeOH (1:1). A total of 25 chromatographic systems are analyzed using a solvation equation. In general, most of the systems give reasonable statistics. The selectivity of the reversed phase-high-performance liquid chromatographic (HPLC) systems with respect to the solute's dipolarity-polarity, hydrogen-bond acidity, and basicity are reflected in correspondingly large coefficients in the solvation equation. We wanted to find the most orthogonal HPLC systems, showing the highest possible selectivity difference in order to derive molecular descriptors using the gradient retention times of a compound. We selected eight chromatographic systems that have a large range of coefficients of interest (s, a, and b) similar to those found in water-solvent partitions used previously to derive molecular descriptors. The systems selected are IN-ODS phases with AcN, MeOH, TFE, and HFIP as mobile phase, PLRP-S 100 phase with AcN, propylcyano phase with AcN and MeOH, and fluorooctyl phase with TFE. Using the retention data obtained for a compound in the selected chromatographic systems, we can estimate the molecular descriptors with the faster and simpler gradient elution method.

Effects of chromatographic fractions of Euphorbia hirta on the rat ...

African Journals Online (AJOL)

The effects of the chromatographic fractions of Euphorbia hirta Linn on the serum biochemical parameters in rats were investigated. The ethanolic extract of this plant was subjected to chromatographic separation using the vacuum liquid chromatographic technique, a modified form of classical column chromatography.

Comprehensive two-dimensional liquid chromatographic analysis of poloxamers.

Science.gov (United States)

Malik, Muhammad Imran; Lee, Sanghoon; Chang, Taihyun

2016-04-15

Poloxamers are low molar mass triblock copolymers of poly(ethylene oxide) (PEO) and poly(propylene oxide) (PPO), having number of applications as non-ionic surfactants. Comprehensive one and two-dimensional liquid chromatographic (LC) analysis of these materials is proposed in this study. The separation of oligomers of both types (PEO and PPO) is demonstrated for several commercial poloxamers. This is accomplished at the critical conditions for one of the block while interaction for the other block. Reversed phase LC at CAP of PEO allowed for oligomeric separation of triblock copolymers with regard to PPO block whereas normal phase LC at CAP of PPO renders oligomeric separation with respect to PEO block. The oligomeric separation with regard to PEO and PPO are coupled online (comprehensive 2D-LC) to reveal two-dimensional contour plots by unconventional 2D IC×IC (interaction chromatography) coupling. The study provides chemical composition mapping of both PEO and PPO, equivalent to combined molar mass and chemical composition mapping for several commercial poloxamers. Copyright © 2016 Elsevier B.V. All rights reserved.

Radioimmunoassay of methaqualone in human urine compared with chromatographic methods

International Nuclear Information System (INIS)

Mule, S.J.; Kogan, M.; Jukofsky, D.

1978-01-01

The 125 I-radioimmunoassay for methaqualone in human urine was evaluated by a comparison with newly modified gas-liquid chromatographic and thin-layer chromatographic methods. The statistically significant sensitivity value for the radioimmunoassay was at 2 μg of methaqualone per liter of urine. The coefficient of variation was 2.88 -+ 0.16% intraassay. There was cross-reactivity only with metabolites of methaqualone, 4'-hydroxymethaqualone being twice as sensitively measured as methaqualone. There was complete agreement between results by radioimmunoassay and by gas-liquid chromatography in 96.7% of the samples analyzed. Only 1.2% of the radioimmunoassay values were false positives, and 2.1% false negatives (phi = 0.8917, P < 0.001). Comparisons between the thin-layer chromatographic data and the gas--liquid chromatographic or radioimmunoassay data showed less agreement because of the 50- to 200-fold higher sensitivity of the latter techniques. Gas--liquid chromatography therefore appears to represent the best reference method for the evaluation of the radioimmunoassay, which appears to be a very sensitive and reliable technique for detecting methaqualone and its metabolites in human urine

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.

Liquid Chromatography with Electrospray Ionization and Tandem Mass Spectrometry Applied in the Quantitative Analysis of Chitin-Derived Glucosamine for a Rapid Estimation of Fungal Biomass in Soil

Directory of Open Access Journals (Sweden)

Madelen A. Olofsson

2016-01-01

Full Text Available This method employs liquid chromatography-tandem mass spectrometry to rapidly quantify chitin-derived glucosamine for estimating fungal biomass. Analyte retention was achieved using hydrophilic interaction liquid chromatography, with a zwitter-ionic stationary phase (ZIC-HILIC, and isocratic elution using 60% 5 mM ammonium formate buffer (pH 3.0 and 40% ACN. Inclusion of muramic acid and its chromatographic separation from glucosamine enabled calculation of the bacterial contribution to the latter. Galactosamine, an isobaric isomer to glucosamine, found in significant amounts in soil samples, was also investigated. The two isomers form the same precursor and product ions and could not be chromatographically separated using this rapid method. Instead, glucosamine and galactosamine were distinguished mathematically, using the linear relationships describing the differences in product ion intensities for the two analytes. The m/z transitions of 180 → 72 and 180 → 84 were applied for the detection of glucosamine and galactosamine and that of 252 → 126 for muramic acid. Limits of detection were in the nanomolar range for all included analytes. The total analysis time was 6 min, providing a high sample throughput method.

Investigating the Effect of Column Geometry on Separation Efficiency using 3D Printed Liquid Chromatographic Columns Containing Polymer Monolithic Phases.

Science.gov (United States)

Gupta, Vipul; Beirne, Stephen; Nesterenko, Pavel N; Paull, Brett

2018-01-16

Effect of column geometry on the liquid chromatographic separations using 3D printed liquid chromatographic columns with in-column polymerized monoliths has been studied. Three different liquid chromatographic columns were designed and 3D printed in titanium as 2D serpentine, 3D spiral, and 3D serpentine columns, of equal length and i.d. Successful in-column thermal polymerization of mechanically stable poly(BuMA-co-EDMA) monoliths was achieved within each design without any significant structural differences between phases. Van Deemter plots indicated higher efficiencies for the 3D serpentine chromatographic columns with higher aspect ratio turns at higher linear velocities and smaller analysis times as compared to their counterpart columns with lower aspect ratio turns. Computational fluid dynamic simulations of a basic monolithic structure indicated 44%, 90%, 100%, and 118% higher flow through narrow channels in the curved monolithic configuration as compared to the straight monolithic configuration at linear velocities of 1, 2.5, 5, and 10 mm s -1 , respectively. Isocratic RPLC separations with the 3D serpentine column resulted in an average 23% and 245% (8 solutes) increase in the number of theoretical plates as compared to the 3D spiral and 2D serpentine columns, respectively. Gradient RPLC separations with the 3D serpentine column resulted in an average 15% and 82% (8 solutes) increase in the peak capacity as compared to the 3D spiral and 2D serpentine columns, respectively. Use of the 3D serpentine column at a higher flow rate, as compared to the 3D spiral column, provided a 58% reduction in the analysis time and 74% increase in the peak capacity for the isocratic separations of the small molecules and the gradient separations of proteins, respectively.

An improved high-performance liquid chromatographic method for simultaneous determination of tocopherols, tocotrienols and γ-oryzanol in rice.

Science.gov (United States)

Huang, Shao-Hua; Ng, Lean-Teik

2011-07-22

An improved normal phase high performance liquid chromatographic (NP-HPLC) method was developed for simultaneous quantification of eight vitamin E isomers (α-, β-, γ- and δ-tocopherols and α-, β-, γ- and δ-tocotrienols) and γ-oryzanol in rice. A complete separation of all compounds was achieved within 25 min using an Inertsil CN-3, SIL-100A 5 μM (4.6 mm × 250 mm) column and an isocratic elution system of hexane/isopropanol/ethylacetate/acetic acid (97.6:0.8:0.8:0.8, v/v/v/v) at a flow rate varying from 0.7 to 1.5 mL min(-1). A linear correlation coefficient (r(2)>0.99) and high reproducibility were obtained at concentrations ranging 0.05-10 μg mL(-1) for vitamin E isomers and 0.5-500 μg mL(-1) for γ-oryzanol. This method proved to be rapid, accurate and reproducible. Copyright © 2011 Elsevier B.V. All rights reserved.

High-performance liquid chromatographic determination of isoniazid and 1-isonicotinyl-2-lactosylhydrazine in isoniazid tablet formulations.

Science.gov (United States)

Butterfield, A G; Lovering, E G; Sears, R W

1980-02-01

A high-performance liquid chromatographic procedure is presented for the simultaneous determination of isoniazid and 1-isonicotinyl-2-lactosylhydrazine (I) in isoniazid tablet formulations. An aliquot of a diluted aqueous tablet extract is introduced onto a microparticulate cyanopropyl bonded-phase column using a valve-loop injector and chromatographed using a mobile phase of acetonitrile--0.01 M, pH 3.5 aqueous acetate buffer (5:95). Compound I can be determined at levels as low as 0.5% of the isoniazid label claim. The relative standard deviations are 0.4 and 0.7% for the simultaneous determination of isoniazid and I, respectively. Seven commercial tablet formulations contained 93.8--97.0% of the labeled isoniazid amounts and 0.3--5.8% of I, expressed as equivalent isoniazid relative to the labeled isoniazid level.

High-pressure liquid chromatographic determination of chlorphenesin carbamate and the beta-isomeric carbamate.

Science.gov (United States)

Beyer, W F

1976-12-01

A high-pressure liquid chromatographic assay was developed for the determination of chlorphenesin carbamate and its beta-isomeric carbamate. A single 4-mm i.d. X 30-cm column, prepacked with 10 micrometer fully porous silica gel particles, is used with 3% methanol in 50% water-saturated butyl chloride as the mobile phase. The procedure separates chlorphenesin carbamate from several possible impurities in addition to the beta-isomeric carbamate. The assay was applied to bulk drug and compressed tablets. The relative standard deviations for the assays of chlorphenesin carbamate and the beta-isomer are approximately 1 and 2%, respectively.

Characterization of Chinese rice wine taste attributes using liquid chromatographic analysis, sensory evaluation, and an electronic tongue.

Science.gov (United States)

Yu, HaiYan; Zhao, Jie; Li, Fenghua; Tian, Huaixiang; Ma, Xia

2015-08-01

To evaluate the taste characteristics of Chinese rice wine, wine samples sourced from different vintage years were analyzed using liquid chromatographic analysis, sensory evaluation, and an electronic tongue. Six organic acids and seventeen amino acids were measured using high performance liquid chromatography (HPLC). Five monosaccharides were measured using anion-exchange chromatography. The global taste attributes were analyzed using an electronic tongue (E-tongue). The correlations between the 28 taste-active compounds and the sensory attributes, and the correlations between the E-tongue response and the sensory attributes were established via partial least square discriminant analysis (PLSDA). E-tongue response data combined with linear discriminant analysis (LDA) were used to discriminate the Chinese rice wine samples sourced from different vintage years. Sensory evaluation indicated significant differences in the Chinese rice wine samples sourced from 2003, 2005, 2008, and 2010 vintage years in the sensory attributes of harmony and mellow. The PLSDA model for the taste-active compounds and the sensory attributes showed that proline, fucose, arabinose, lactic acid, glutamic acid, arginine, isoleucine, valine, threonine, and lysine had an influence on the taste characteristic of Chinese rice wine. The Chinese rice wine samples were all correctly classified using the E-tongue and LDA. The electronic tongue was an effective tool for rapid discrimination of Chinese rice wine. Copyright © 2015 Elsevier B.V. All rights reserved.

Rapid planar chromatographic analysis of 25 water-soluble dyes used as food additives.

Science.gov (United States)

Morlock, Gertrud E; Oellig, Claudia

2009-01-01

A rapid planar chromatographic method for identification and quantification of 25 water-soluble dyes in food was developed. In a horizontal developing chamber, the chromatographic separation on silica gel 60F254 high-performance thin-layer chromatography plates took 12 min for 40 runs in parallel, using 8 mL ethyl acetate-methanol-water-acetic acid (65 + 23 + 11 + 1, v/v/v/v) mobile phase up to a migration distance of 50 mm. However, the total analysis time, inclusive of application and evaluation, took 60 min for 40 runs. Thus, the overall time/run can be calculated as 1.5 min with a solvent consumption of 200 microL. A sample throughput of 1000 runs/8 h day can be reached by switching between the working stations (application, development, and evaluation) in a 20 min interval, which triples the analysis throughput. Densitometry was performed by absorption measurement using the multiwavelength scan mode in the UV and visible ranges. Repeatabilities [relative standard deviation (RSD), 4 determinations] at the first or second calibration level showed precisions of mostly or = 0.9987) and RSD values ( or = 0.9996). If necessary for confirmation, online mass spectra were recorded within a minute.

Alternative solvent-based methyl benzoate vortex-assisted dispersive liquid-liquid microextraction for the high-performance liquid chromatographic determination of benzimidazole fungicides in environmental water samples.

Science.gov (United States)

Santaladchaiyakit, Yanawath; Srijaranai, Supalax

2014-11-01

Vortex-assisted dispersive liquid-liquid microextraction using methyl benzoate as an alternative extraction solvent for extracting and preconcentrating three benzimidazole fungicides (i.e., carbendazim, thiabendazole, and fluberidazole) in environmental water samples before high-performance liquid chromatographic analysis has been developed. The selected microextraction conditions were 250 μL of methyl benzoate containing 300 μL of ethanol, 1.0% w/v sodium acetate, and vortex agitation speed of 2100 rpm for 30 s. Under optimum conditions, preconcentration factors were 14.5-39.0 for the target fungicides. Limits of detection were obtained in the range of 0.01-0.05 μg/L. The proposed method was then applied to surface water samples and the recovery evaluations at three spiked concentration levels of 5, 30, and 50 μg/L were obtained in the range of 77.4-110.9% with the relative standard deviation water samples. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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.

[Reversed-phase high-performance liquid chromatograph--application to serum aluminium monitoring].

Science.gov (United States)

Hoshino, H; Kaneko, E

1996-01-01

High-Performance Liquid Chromatography (HPLC) with the reversed-phase partition mode separation (including ion-pair one) towards metal chelate compounds prepared in an off-line fashion (precolumn chelation) is most versatile in terms of high sensitivity with base-line flatness, unique selectivity and cost effectiveness. The extraordinary toughness to the complicated matrices encountered in clinical testing is exemplified by the successful application to the aluminium monitoring of human serum samples. The A1 chelate with 2,2'-dihydroxyazobenzene is efficiently chromatographed on a LiChroCART RP-18 column using an aqueous methanol eluent (63.6 wt%) containing tetrabutylammonium bromide as an ion-pair agent. The serum concentration level of A1 down to 6 micrograms dm-3 is readily monitored without influences from iron, chyle and haemolysis.

Storing of Extracts in Polypropylene Microcentrifuge Tubes Yields Contaminant Peak During Ultra-flow Liquid Chromatographic Analysis

OpenAIRE

Kshirsagar, Parthraj R.; Hegde, Harsha; Pai, Sandeep R.

2016-01-01

Background and Aim: This study was designed to understand the effect of storage in polypropylene microcentrifuge tubes and glass vials during ultra-flow liquid chromatographic (UFLC) analysis. Materials and Methods: One ml of methanol was placed in polypropylene microcentrifuge tubes (PP material, Autoclavable) and glass vials (Borosilicate) separately for 1, 2, 4, 8, 10, 20, 40, and 80 days intervals stored at ?4?C. Results: Contaminant peak was detected in methanol stored in polypropylene m...

Identification and quantification of flavonoids in human urine samples by column switching liquid chromatography coupled to atmospheric pressure chemical ionization mass spectrometry

DEFF Research Database (Denmark)

Nielsen, Salka E.; Freese, R.; Cornett, C.

2000-01-01

A rapid and sensitive high-performance liquid chromatographic mass spectrometric (HPLC-MS) method is described for the determination and quantification of 12 dietary flavonoid glycosides and aglycons in human urine samples. Chromatographic separation of the analytes of interest was achieved...

Total cholesterol in serum determined by isotope dilution/mass spectrometry, with liquid-chromatographic separation

International Nuclear Information System (INIS)

Takatsu, Akiko; Nishi, Sueo

1988-01-01

We describe an accurate, precise method for determination of total serum cholesterol by isotope dilution/mass spectrometry (IDMS) with liquid chromatographic separation. After adding [3,4- 13 C] cholesterol to serum and hydrolyzing the cholesterol esters, we extract the total cholesterol. High-performance liquid chromatography (HPLC) is used to separate the extracted cholesterol for measurement by electron-impact mass spectrometry with use of a direct-insertion device. To evaluate the specificity and the accuracy of this method, we also studied the conventional IDMS method, which involves converting cholesterol to the trimethylsilyl ether and assay by gas chromatography-mass spectrometry with use of a capillary column. The coefficient of variation for the HPLC method was a little larger than for the conventional method, but mean values by each method agreed within 1% for all sera tested. (author)

A simple high-performance liquid chromatographic method for the estimation of boswellic acids from the market formulations containing Boswellia serrata extract.

Science.gov (United States)

Shah, Shailesh A; Rathod, Ishwarsinh S; Suhagia, Bhanubhai N; Pandya, Saurabh S; Parmar, Vijay K

2008-09-01

A simple, rapid, and reproducible reverse-phase high-performance liquid chromatographic method is developed for the estimation of boswellic acids, the active constituents in Boswellia serrata oleo-gum resin. The chromatographic separation is performed using a mobile phase consisting of acetonitrile-water (90:10, % v/v) adjusted to pH 4 with glacial acetic acid on a Kromasil 100 C18 analytical column with flow rate of 2.0 mL/min and detection at 260 nm. The elution times are 4.30 and 7.11 min for 11-keto beta-boswellic acid (11-KBA) and 3-acetyl 11-keto beta-boswellic acid (A-11-KBA), respectively. The calibration curve is linear in the 11.66-58.30 microg/mL and 6.50-32.50 microg/mL range for 11-KBA and A-11-KBA, respectively. The limits of detection are 2.33 microg/mL and 1.30 microg/mL for 11-KBA and A-11-KBA, respectively. The mean recoveries are 98.24% to 104.17% and 94.12% to 105.92% for 11-KBA and A-11-KBA, respectively. The inter- and intra-day variation coefficients are less than 5%. The present method is successfully applied for the estimation of boswellic acids from the market formulations containing Boswellia serrata extract.

Analysis and chromatographic purification of eicosanoids multiply labeled by tritium

International Nuclear Information System (INIS)

Shevchenko, V.P.; Nagaev, I.Yu.; Myasoedov, N.F.

1989-01-01

We show the possibility of analysis and chromatographic purification of eicosanoids triply labeled by tritium. The described methods allow us to isolate chromatographically pure products obtained by selective hydrogenatin, chemical, and enzyme methods, with radiochemical purity at least 95-97%. The following methods are used to analyze the reaction mixtures and to isolate the tritium-labeled eicosanoids: gas-liquid chromatography, high-efficiency liquid chromatography, and thin-layer chromatography on supports impregnated with silver nitrate

INTERLABORATORY STUDY OF A THERMOSPRAY-LIQUID CHROMATOGRAPHIC/MASS SPECTROMETRIC METHOD FOR SELECTED N-METHYL CARBAMATES, N-METHYL CARBAMOYLOXIMES, AND SUBSTITUTED UREA PESTICIDES

Science.gov (United States)

A thermospray-liquid chromatographic/mass spectrometric (TS-LC/MS) method was evaluated in an interlaboratory study for determining 3 N-methyl carbamates (bendiocarb, carbaryl, and carbofuran), 3-N-methyl carbamoyloximes (aldicarb, methomyl, and oxamyl), 2 substituted urea pestic...

A Selective High Performance Liquid Chromatographic Method to Follow the Hydrolytic Degradation of Nicardipine Hydrochloride

Directory of Open Access Journals (Sweden)

K. E. Ibrahim

2010-01-01

Full Text Available A simple, stability indicating, reverse phase high performance liquid chromatographic method was developed and validated for determination of nicardipine hydrochloride (NC in the presence of its degradation products. The chromatographic separation was performed on Hypersil, BDS-C18, 30 cm × 3.9 mm id, at ambient temperature with UV-detection at 254 nm. A mixture of 20% (v/v aqueous 0.01 M sodium acetate∕acetic acid buffer (pH 4.5 and 80% acetonitrile was used as the mobile phase at a flow rate of 1.5 mL min-1, losartan was used as internal standard. The calibration curve is linear over the concentration range 5-40 μg mL-1, with a regression coefficient of 0.9984 and the % recovery was 99.78±0.17. The method was used to investigate the kinetics of alkaline, acids induced degradation, effect of buffer concentration and temperature. The degradation followed first-order kinetics. The rate constant, half-life time, and activation energy were calculated

Diagnosis of rinderpest in Tanzania by a rapid chromatographic strip-test.

Science.gov (United States)

Wambura, P N; Moshy, D W; Mbise, A N; Mollel, G O; Taylor, W P; Anderson, J; Bruning, A

2000-06-01

A simple chromatographic strip-test based on Clearview technology, is under development as a pen-side test for the detection of rinderpest antigen in eye swabs taken from cattle in the field. An outbreak of rinderpest occurred in the northern zone of Tanzania from late February to June 1997. The affected cattle exhibited very mild clinical signs, which made clinical diagnosis difficult. One hundred and seven eye swabs were collected from cattle suspected of infection with rinderpest. These were tested in the field using a prototype of the pen-side test and 13 (12.15%) of the samples were found to be positive for the presence of rinderpest antigen. These were confirmed by ICE. The positive cases were predominantly found in the Ngorongoro district. This demonstrates the usefulness of such a simple, rapid pen-side diagnostic assay, particularly when clinically 'mild' strains of rinderpest are present.

Liquid-chromatographic determination of sarafloxacin residues in channel catfish muscle-tissue

Science.gov (United States)

Meinertz, J.R.; Dawson, V.K.; Gingerich, W.H.; Cheng, B.; Tubergen, M.M.

1994-01-01

A liquid chromatographic method is described for the determination of sarafloxacin hydrochloride residues i n channel catfish (ictalurus punctatus) fillets. Sarafloxacin was extracted from fillet tissue with acetonitrile=water (1 + 1). The extract was centrifuged and the supernatant was partitioned with hexane. The aqueous fraction was filtered through a 0.45 Mum filter and evaporated to dryness. The sample was redissolved with 20% acetonitrile-methanol (3 + 2) and 80% trifluoroacetic acid (0.1%), Centrifuged, and filtered to remove proteins. Samples were analyzed by chromatography with gradient elution on a c18 column and with fluorescence detection (excitation at 280 nm and emission above 389 nm). Mean recoveries ranged from 85.4 To 104%, and relative standard deviations ranged from 1.06 To 5.58% In samples spiked at concentrations of 10.0-863.8 Ng/g. The method detection limit for sarafloxacin was 1.4 Ng/g.

A simple and rapid ultra-high-performance liquid chromatography-tandem mass spectrometry method to determine plasma biotin in hemodialysis patients.

Science.gov (United States)

Yagi, Shigeaki; Nishizawa, Manabu; Ando, Itiro; Oguma, Shiro; Sato, Emiko; Imai, Yutaka; Fujiwara, Masako

2016-08-01

A simple, rapid, and selective method for determination of plasma biotin was developed using ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). After single-step protein precipitation with methanol, biotin and stable isotope-labeled biotin as an internal standard (IS) were chromatographed on a pentafluorophenyl stationary-phase column (2.1 × 100 mm, 2.7 μm) under isocratic conditions using 10 mm ammonium formate-acetonitrile (93:7, v/v) at a flow rate of 0.6 mL/min. The total chromatographic runtime was 5 min for each injection. Detection was performed in a positive electrospray ionization mode by monitoring selected ion transitions at m/z 245.1/227.0 and 249.1/231.0 for biotin and the IS, respectively. The calibration curve was linear in the range of 0.05-2 ng/mL using 300 μL of plasma. The intra- and inter-day precisions were all biotin concentrations in hemodialysis patients. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Mixed-mode chromatographic matrices for the resolution of transfer ribonucleic acids

NARCIS (Netherlands)

Bischoff, Rainer; Mclaughlin, L.W.

1984-01-01

Modification of approximately 65% of the amine groups of an aminopropylsilyl bonded-phase silica high-performance liquid chromatographic anion exchanger (APS-Hypersil) with organic acids containing n-alkyl moieties of different chain lengths, results in mixed mode chromatographic matrices of varying

Liquid chromatographic-tandem mass spectrometric assay for ...

African Journals Online (AJOL)

Methods: Blood and urine samples were obtained from healthy volunteers who admitted to not being on any medications. The investigated analytes were chromatographically separated on a C18 column (Luna®-PFP 100Å column, 50 mm × 2.0 mm i.d., 3.0 μm) with the aid of a mobile phase containing A; acetonitrile (ACN) ...

Rapid and Convenient Separation of Chitooligosaccharides by Ion-Exchange Chromatography

Science.gov (United States)

Wu, Yuxiao; Lu, Wei-Peng; Wang, Jianing; Gao, Yunhua; Guo, Yanchuan

2017-12-01

Pervious methods for separation of highly purified chitooligosaccharides was time-consuming and labor-intensive, which limited the large-scale production. This study developed a convenient ion-exchange chromatography using the ÄKTA™ avant 150 chromatographic system. Five fractions were automatically collected under detecting the absorption at 210 nm. The fractions were analyzed by high-performance liquid chromatography. It proved that they primarily comprised chitobiose, chitotriose, chitotetraose, chitopentaose, and chitohexaose, respectively, with chromatographic purities over 90%. The separation process was rapid, convenient and could be monitored on-line, which would be benefit for the mass production of chitooligosaccharides.

Optimization of the reversed-phase high-performance liquid chromatographic separation of synthetic estrogenic and progestogenic steroids using the multi-criteria decision making method

NARCIS (Netherlands)

Smilde, A. K.; Bruins, C. H.; Doornbos, D. A.; Vink, J.

1987-01-01

The optimization of the reversed-phase high-performance liquid chromatographic separation of a mixture of ethynylestradiol, desogestrel and three related compounds is described. A procedure is used that allows the prediction of the capacity factors of each individual synthetic steroid, depending on

Precolumn derivatization followed by liquid chromatographic separation and determination of tramiprosate in rat plasma by fluorescence detector: application to pharmacokinetics.

Science.gov (United States)

Rao, R Nageswara; Maurya, Pawan K; Shinde, Dhananjay D; Khalid, Sara

2011-05-15

Alzheimer disease (AD) is characterized pathologically by extracellular amyloid deposits composed of amyloid β (Aβ) protein. A simple and rapid method using HPLC with fluorescence detector was developed and validated for determination of tramiprosate in rat plasma. Pre-column derivatization of the deproteinized rat plasma was carried out using o-phthaldialdehyde (OPA) as a fluorescent reagent in presence of 3-mercaptopropionic acid. The liquid chromatographic separation was achieved on a Kromasil C18 column using methanol:acetonitrile: 20 mM phosphate buffer pH 7.5 (8.0:17.5:74.5 v/v/v) as a mobile phase in an isocratic elution mode. The eluents were monitored by a fluorescence detector set at 330 and 450 nm of excitation and emission wavelength respectively. Vigabatrin was used as an internal standard. The method was linear within the range 30.0-1000.0 ng/mL. Design of experiments (DOE) was used to evaluate the robustness of the method. The developed method was applied to study the pharmacokinetics of tramiprosate in rats. Copyright © 2011. Published by Elsevier B.V.

A liquid chromatographic method for determination of theophylline in serum and capillary blood--a comparison.

Science.gov (United States)

Gartzke, J; Jäger, H; Vins, I

1991-01-01

A simple, fast and reliable liquid chromatographic method for the determination of theophylline in serum and capillary blood after a solid phase extraction is described for therapeutic drug monitoring. The employment of capillary blood permits the determination of an individual drug profile and other pharmacokinetic studies in neonates and infants. There were no differences in venous- and capillary-blood levels but these values compared poorly with those in serum. An adjustment of the results by correction of the different volumes of serum and blood by haematocrit was unsuccessful. Differences in the binding of theophylline to erythrocytes could be an explanation for the differences in serum at blood levels of theophylline.

Comparison of two validated gas-chromatographic methods for the determination of trihalomethanes in drinking water Comparação de dois métodos cromatográficos validados para a dosagem de trialometanos em água potável

OpenAIRE

Maria Yumiko Tominaga; Antonio Flavio Mídio

2003-01-01

In this paper the results obtained using two validated gas-chromatographic procedures on drinking water for the determination of trihalomethanes are compared. The volatile compounds, chloroform (CF), bromodichloromethane (BDCM), dibromochloromethane (DBCM) and bromoform (BF) were detected by purge and trap capillary column gas-chromatography with electrolytic conductivity detector ( ELCD) and the simple and rapid gas-chromatographic method by electron capture detector (ECD) after liquid-liqui...

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.

Liquid chromatographic method for simultaneous determination of citalopram with NSAIDs in bulk drug, pharmaceutical formulation and human serum

International Nuclear Information System (INIS)

Ali, S.N.; Akram, S.

2017-01-01

A high performance liquid chromatographic method was developed and validated to simultaneously quantify citalopram with piroxicam, celecoxib and diclofenac sodium. Chromatographic analysis was performed at ambient temperature using Shimadzu Shim-pack CLC-ODS (M) 25M column linked to a UV-visible detector adjusted at 230 nm, employing 80:20 (v/v) methanol: water (pH 3.5) as mobile phase with flow rate 1.0 mL min-1. Validation was performed in the ranges 0.6-20, 0.9-28, 0.6-20 and 1.0-32 mu g mL-1 with lowest level corresponding to detection limit 16.45, 23.33, 27.66 and 14.44 ng mL-1 respectively. With-in the day precision ranged from 0.14-1.67% and between-day precision from 0.40-1.50%, accuracies were 99.61-100.86%. The analytes were successfully detected without any observable interference in pharmaceutical formulation and human serum samples demonstrating effectiveness of method. (author)

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.

Performance of chromatographic systems to model soil-water sorption.

Science.gov (United States)

Hidalgo-Rodríguez, Marta; Fuguet, Elisabet; Ràfols, Clara; Rosés, Martí

2012-08-24

A systematic approach for evaluating the goodness of chromatographic systems to model the sorption of neutral organic compounds by soil from water is presented in this work. It is based on the examination of the three sources of error that determine the overall variance obtained when soil-water partition coefficients are correlated against chromatographic retention factors: the variance of the soil-water sorption data, the variance of the chromatographic data, and the variance attributed to the dissimilarity between the two systems. These contributions of variance are easily predicted through the characterization of the systems by the solvation parameter model. According to this method, several chromatographic systems besides the reference octanol-water partition system have been selected to test their performance in the emulation of soil-water sorption. The results from the experimental correlations agree with the predicted variances. The high-performance liquid chromatography system based on an immobilized artificial membrane and the micellar electrokinetic chromatography systems of sodium dodecylsulfate and sodium taurocholate provide the most precise correlation models. They have shown to predict well soil-water sorption coefficients of several tested herbicides. Octanol-water partitions and high-performance liquid chromatography measurements using C18 columns are less suited for the estimation of soil-water partition coefficients. Copyright © 2012 Elsevier B.V. All rights reserved.

Gas--liquid chromatographic determination of total inorganic iodine in milk

International Nuclear Information System (INIS)

Bakker, H.J.

1977-01-01

Total inorganic iodine in milk is determined by conversion to iodobutanone, which is quantitated by gas-liquid chromatography and electron capture detection. As little as 10 μg/L can be determined. The thyroid-active iodine content of milk can be determined rapidly with a relative standard deviation of 1.9%. Average recoveries for added iodide and iodine were 95.5 and 94.6%, respectively

Liquid chromatographic and ultraviolet spectrophotometric determination of bevantolol and hydrochlorothiazide in feeds.

Science.gov (United States)

Spurlock, C H; Schneider, H G

1984-01-01

Separate assay methods have been developed for the 2 components of an 80 + 20 drug blend of bevantolol and hydrochlorothiazide (HCT) in admixtures with animal feed. Drug/diet admixtures are extracted with methanol for reverse phase ion-pair liquid chromatographic (LC) assay of bevantolol, and with acetonitrile for ultraviolet spectrophotometric assay of HCT. Bevantolol, a cardioselective beta blocker, is separated from soluble feed components with an RP-18 column, using methanol-water-acetic acid (60 + 40 + 1) containing 0. 005M octane-sulfonic acid, sodium salt, as ion-pairing reagent. HCT is determined spectrophotometrically in acetonitrile extracts, using a suitable blank extract as reference. Average recovery of HCT from an admixture of 0.5 mg blend/g diet is 94.5% +/- 4.3 RSD and at 2.0 mg/g, 101.5% +/- 3.5 RSD. Bevantolol recovery from the same admixtures is 101.8% +/- 2.7 RSD and 99.0% +/- 3.5 RSD, respectively, using the method as described.

A multiresidue method by high performance liquid chromatography-based fractionation and gas chromatographic determination of trace levels of pesticides in air and water.

Science.gov (United States)

Seiber, J N; Glotfelty, D E; Lucas, A D; McChesney, M M; Sagebiel, J C; Wehner, T A

1990-01-01

A multiresidue analytical method is described for pesticides, transformation products, and related toxicants based upon high performance liquid chromatographic (HPLC) fractionation of extracted residue on a Partisil silica gel normal phase column followed by selective-detector gas chromatographic (GC) determination of components in each fraction. The HPLC mobile phase gradient (hexane to methyl t-butyl ether) gave good chromatographic efficiency, resolution, reproducibility and recovery for 61 test compounds, and allowed for collection in four fractions spanning polarities from low polarity organochlorine compounds (fraction 1) to polar N-methylcarbamates and organophosphorus oxons (fraction 4). The multiresidue method was developed for use with air samples collected on XAD-4 and related trapping agents, and water samples extracted with methylene chloride. Detection limits estimated from spiking experiments were generally 0.3-1 ng/m3 for high-volume air samples, and 0.01-0.1 microgram/L for one-liter water samples. Applications were made to determination of pesticides in fogwater and air samples.

Rapid determination of methadone and its major metabolite in biological fluids by gas-liquid chromatography with thermionic detection for maintenance treatment of opiate addicts.

Science.gov (United States)

Chikhi-Chorfi, N; Pham-Huy, C; Galons, H; Manuel, N; Lowenstein, W; Warnet, J M; Claude, J R

1998-11-06

A rapid gas-liquid chromatographic assay is developed for the quantification of methadone (Mtd) and its major metabolite, 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine (EDDP), in biological fluids of opiate addicts. After alkaline extraction from samples with lidocaine hydrochloride as internal standard, Mtd and EDDP are separated on SP-2250 column at 220 degrees C and detected with a thermionic detector. The chromatographic time is about 6 min. The relative standard deviations (R.S.D.) of Mtd and EDDP standards are between 1.5 and 5.5%. Most drugs of abuse (morphine, codeine, narcotine, cocaine, benzoylecgonine, cocaethylene, dextropropoxyphene etc) are shown not to interfere with this technique. The method has been applied to study the levels of Mtd and EDDP metabolite in serum, saliva and urine of patients under maintenance treatment for opiate dependence. EDDP levels were found higher than those of Mtd in urine samples from four treated patients, but lower in serum and undetectable in saliva. However, Mtd concentrations were higher in saliva than in serum.

Inductively coupled plasma emission spectrometric detection of simulated high performance liquid chromatographic peaks

International Nuclear Information System (INIS)

Fraley, D.M.; Yates, D.; Manahan, S.E.

1979-01-01

Because of its multielement capability, element-specificity, and low detection limits, inductively coupled plasma optical emission spectrometry (ICP) is a very promising technique for the detection of specific elemental species separated by high performance liquid chromatography (HPLC). This paper evaluated ICP as a detector for HPLC peaks containing specific elements. Detection limits for a number of elements have been evaluated in terms of the minimum detectable concentration of the element at the chromatographic peak maximum. The elements studies were Al, As, B, Ba, Ca, Cd, Co, Cr, Cu, Fe, K, Li, Mg, Mn, Mo, Na, Ni, P, Pb, Sb, Se, Sr, Ti, V, and Zn. In addition, ICP was compared with atomic absorption spectrometry for the detection of HPLC peaks composed of EDTA and NTA chelates of copper. Furthermore, ICP was compared to uv solution absorption for the detection of copper chelates. 6 figures, 4 tables

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...

Liquid chromatographic determination of polyphenenols in czech beers during brewing proces

Directory of Open Access Journals (Sweden)

Chunsriimyatav Ganbaatar

2015-05-01

Full Text Available High performance liquid chromatographic (HPLC/UV method was adapted for simultaneous determination of seven polyphenols, including derivatives of benzoic (gallic and vanillic acids and cinnamic acids (p-coumaric, ferulic and sinapic acids, flavan-3-ols (catechin and flavonols (rutin in worts and beers at the various stages of the brewing process. Based on the semi-quantitative HPLC analysis, total polyphenols chromatographic index (TPCI was in the ranges of 5.18 - 19.4 mg/L and 7.37 - 20.7 mg/L for all worts and beers, respectively. The HPLC analyses showed that relatively high levels of (+-catechin and gallic acid were in all the worts and the beers, while the values were much lower for ferulic acid, rutin, vanillic acid, sinapic acid and p-coumaric acid. Polyphenols with relatively high concentrations, that were detected in all tested worts and beers, were gallic acid (1.29 - 4.75 mg/L resp. 2.59 - 4.97 mg/L, (+-catechin (1.66 - 7.95 mg/L resp. 4.70 - 10.0 mg/L and ferulic acid (0.41 - 4.53 mg/L resp. 1.05 - 2.87 mg/L. On the other side, the sinapic acid (0.72 - 1.59 mg/L resp. 0.72 - 2.5 mg/L, rutin (1.17 - 2.03 mg/L resp. 1.16 - 2.85 mg/L, p-coumaric acid (ND - 4.73 mg/L resp. ND - 1.44 mg/L and vanillic acid (ND - 1.52 mg/L resp. 0.75 - 1.81 mg/L were detected in lowest concentrations. In both, worts and beers investigated in this study, the changes in the contents of individual polyphenols were not uniform. In the case of some polyphenols, a decrease in the content was observed after boiling the worts with hops or after the main fermentation until maturation and filtration, but with some polyphenols, the concentrations were constant until the end of the process or even increased.

Liquid chromatographic and spectrophotometric methods for the determination of erythromycin stearate and trimethoprim in tablets

Directory of Open Access Journals (Sweden)

Sonia T. Hassib

2011-12-01

Full Text Available Simple, accurate and precise reversed-phase liquid chromatographic (LC and spectrophotometric methods have been developed and validated for the determination of erythromycin stearate (ERS and trimethoprim (TMP in mixture. In LC method, chromatographic separation was achieved on a Symmetry® Waters C18 column (150 × 4.6 mm, 5 μm based on isocratic elution using a mobile phase consisting of potassium dihydrogen phosphate buffer pH (9:acetonitrile:water (25:100:50, v/v/v at a flow rate of 1.6 ml min−1 with UV detection at 210 nm for ERS and 280 nm for TMP. Besides, two spectrophotometric methods were applied after reaction with perchloric acid (12 M which gives a colored product with ERS. Then, the spectral interference between the colored product of ERS and TMP was resolved by either ratio spectra derivative spectrophotometry in the first spectrophotometric method or chemometric techniques, namely classical least-squares (CLS, principal component regression (PCR and partial least-squares regression (PLS in the second spectrophotometric method. The results were statistically compared using one-way analysis of variance (ANOVA. The methods developed were satisfactorily applied to the analysis of the pharmaceutical preparation containing the two drugs and proved to be specific and accurate for the quality control of the cited drugs in pharmaceutical dosage forms.

Development of Chromatographic Fingerprints of Eurycoma longifolia (Tongkat Ali Roots Using Online Solid Phase Extraction-Liquid Chromatography (SPE-LC

Directory of Open Access Journals (Sweden)

Nor Nasriah Zaini

2016-04-01

Full Text Available E. longifolia is attracting interest due to its pharmacological properties and pro-vitality effects. In this study, an online SPE-LC approach using polystyrene divinyl benzene (PSDVB and C18 columns was developed in obtaining chromatographic fingerprints of E. longifolia. E. longifolia root samples were extracted using pressurized liquid extraction (PLE technique prior to online SPE-LC. The effects of mobile phase compositions and column switching time on the chromatographic fingerprint were optimized. Validation of the developed method was studied based on eurycomanone. Linearity was in the range of 5 to 50 µg∙mL−1 (r2 = 0.997 with 3.2% relative standard deviation of peak area. The developed method was used to analyze 14 E. longifolia root samples and 10 products (capsules. Selected chemometric techniques: cluster analysis (CA, discriminant analysis (DA, and principal component analysis (PCA were applied to the fingerprint datasets of 37 selected peaks to evaluate the ability of the chromatographic fingerprint in classifying quality of E. longifolia. Three groups were obtained using CA. DA yielded 100% correlation coefficient with 19 discriminant compounds. Using PCA, E. longifolia root samples were clearly discriminated from the products. This study showed that the developed online SPE-LC method was able to provide comprehensive evaluation of E. longifolia samples for quality control purposes.

A novel two-dimensional liquid chromatographic system for the online toxicity prediction of pharmaceuticals and related substances

Energy Technology Data Exchange (ETDEWEB)

Li, Jian; Xu, Li [Tongji School of Pharmacy, Huazhong University of Science and Technology, Wuhan 430030 (China); Shi, Zhi-guo, E-mail: shizg@whu.edu.cn [Department of Chemistry, Wuhan University, Wuhan 430072 (China); Hu, Min [Hubei Instrument for Food and Drug Control, Wuhan (China)

2015-08-15

Highlights: • A novel two-dimensional liquid chromatographic system was developed. • The 1st dimension was ODS to separate components in the sample. • The 2nd dimension was biopartitioning micellar chromatography to predict toxicity. • The system was used to screen toxicity of pharmaceuticals and related substances. • It was promising for fast online toxicity screening of complex sample in one step. - Abstract: In this study, a novel two-dimensional liquid chromatographic (2D-LC) system was developed for simultaneous separation and toxicity prediction of pharmaceutical and its related substances. A conventional ODS column was used on the 1st-D to separate the sample; while, bio-partitioning micellar chromatography served as the 2nd-D to predict toxicity of the components. The established system was tested for the toxicity of ibuprofen and its impurities with known toxicity. With only one injection, ibuprofen and its impurities were separated on the 1st-D; and LC50 values of individual impurity were obtained based on the quantitative retention–activity relationships, which agreed well with the reported data. Furthermore, LC50 values of photolysis transformation products (TPs) of carprofen, ketoprofen and diclofenac acid (as unknown compounds) were screened in this 2D-LC system, which could be an indicator of the toxicity of these TPs and was meaningful for the environmental monitoring and drinking water treatment. The established 2D-LC system was cost-effective, time-saving and reliable, and was promising for fast online screening of toxicity of known and unknown analytes in the complex sample in a single step. It may find applications in environment, pharmaceutical and food, etc.

A novel two-dimensional liquid chromatographic system for the online toxicity prediction of pharmaceuticals and related substances

International Nuclear Information System (INIS)

Li, Jian; Xu, Li; Shi, Zhi-guo; Hu, Min

2015-01-01

Highlights: • A novel two-dimensional liquid chromatographic system was developed. • The 1st dimension was ODS to separate components in the sample. • The 2nd dimension was biopartitioning micellar chromatography to predict toxicity. • The system was used to screen toxicity of pharmaceuticals and related substances. • It was promising for fast online toxicity screening of complex sample in one step. - Abstract: In this study, a novel two-dimensional liquid chromatographic (2D-LC) system was developed for simultaneous separation and toxicity prediction of pharmaceutical and its related substances. A conventional ODS column was used on the 1st-D to separate the sample; while, bio-partitioning micellar chromatography served as the 2nd-D to predict toxicity of the components. The established system was tested for the toxicity of ibuprofen and its impurities with known toxicity. With only one injection, ibuprofen and its impurities were separated on the 1st-D; and LC50 values of individual impurity were obtained based on the quantitative retention–activity relationships, which agreed well with the reported data. Furthermore, LC50 values of photolysis transformation products (TPs) of carprofen, ketoprofen and diclofenac acid (as unknown compounds) were screened in this 2D-LC system, which could be an indicator of the toxicity of these TPs and was meaningful for the environmental monitoring and drinking water treatment. The established 2D-LC system was cost-effective, time-saving and reliable, and was promising for fast online screening of toxicity of known and unknown analytes in the complex sample in a single step. It may find applications in environment, pharmaceutical and food, etc

Simple fluorimetric liquid chromatographic method for the analysis of undecylenic acid and zinc undecylenate in pharmaceutical preparations.

Science.gov (United States)

Lin, Ming-Chun; Wu, Hsin-Lung; Kou, Hwang-Shang; Wu, Shou-Mei

2006-06-30

A simple and selective liquid chromatographic method is described for the analysis of undecylenic acid (UA) and zinc undecylenate (ZnUA) in pharmaceutical preparations. The method is based on the derivatization of the analytes extracted from various samples with 2-(2-naphthoxy)ethyl 2-(piperidino)ethanesulfonate. The resulting derivative was analyzed by liquid chromatography with fluorimetric detection. The quantitation of the method is in the range of 3.0-50.0 microM UA with a detection limit of about 0.3 microM (S/N = 3 with 10 microl injection). We found that acetonitrile is a selective solvent for differentially dissolving UA from coexisted ZnUA in compound formulation. This results in the specific analysis of UA in the presence of ZnUA and simply analyzing the coexisted ZnUA by the value of total UA (UA+ZnUA) minus that of UA. Application of the method to the analysis of undecylenic acid and zinc undecylenate in ointment, powder and solution preparations proved feasible.

Application of ionic liquids in liquid chromatography and electrodriven separation.

Science.gov (United States)

Huang, Yi; Yao, Shun; Song, Hang

2013-08-01

Ionic liquids (ILs) are salts in the liquid state at ambient temperature, which are nonvolatile, nonflammable with high thermal stability and dissolve easily for a wide range of inorganic and organic materials. As a kind of potential green solvent, they show high efficiency and selectivity in the field of separation research, especially in instrumental analysis. Thus far, ILs have been successfully applied by many related researchers in high-performance liquid chromatography and capillary electrophoresis as chromatographic stationary phases, mobile phase additives or electroosmotic flow modifiers. This paper provides a detailed review of these applications in the study of natural products, foods, drugs and other fine chemicals. Furthermore, the prospects of ILs in liquid chromatographic and electrodriven techniques are discussed.

Warping methods for spectroscopic and chromatographic signal alignment: A tutorial

Energy Technology Data Exchange (ETDEWEB)

Bloemberg, Tom G., E-mail: T.Bloemberg@science.ru.nl [Radboud University Nijmegen, Institute for Molecules and Materials, Heyendaalseweg 135, 6525 AJ Nijmegen (Netherlands); Radboud University Nijmegen, Education Institute for Molecular Sciences, Heyendaalseweg 135, 6525 AJ Nijmegen (Netherlands); Gerretzen, Jan; Lunshof, Anton [Radboud University Nijmegen, Institute for Molecules and Materials, Heyendaalseweg 135, 6525 AJ Nijmegen (Netherlands); Wehrens, Ron [Centre for Research and Innovation, Fondazione Edmund Mach, Via E. Mach, 1, 38010 San Michele all’Adige, TN (Italy); Buydens, Lutgarde M.C. [Radboud University Nijmegen, Institute for Molecules and Materials, Heyendaalseweg 135, 6525 AJ Nijmegen (Netherlands)

2013-06-05

Highlights: •The concepts of warping and alignment are introduced. •The most important warping methods are critically reviewed and explained. •Reference selection, evaluation and place of warping in preprocessing are discussed. •Some pitfalls, especially for LC–MS and similar data, are addressed. •Examples are provided, together with programming scripts to rework and extend them. -- Abstract: Warping methods are an important class of methods that can correct for misalignments in (a.o.) chemical measurements. Their use in preprocessing of chromatographic, spectroscopic and spectrometric data has grown rapidly over the last decade. This tutorial review aims to give a critical introduction to the most important warping methods, the place of warping in preprocessing and current views on the related matters of reference selection, optimization, and evaluation. Some pitfalls in warping, notably for liquid chromatography–mass spectrometry (LC–MS) data and similar, will be discussed. Examples will be given of the application of a number of freely available warping methods to a nuclear magnetic resonance (NMR) spectroscopic dataset and a chromatographic dataset. As part of the Supporting Information, we provide a number of programming scripts in Matlab and R, allowing the reader to work the extended examples in detail and to reproduce the figures in this paper.

High performance liquid chromatographic determination of glucosamine in rat plasma.

Science.gov (United States)

Aghazadeh-Habashi, Ali; Sattari, Saeed; Pasutto, Franco; Jamali, Fakhreddin

2002-01-01

A high performance liquid chromatographic method was developed for the determination of glucosamine (GlcN) in rat plasma. Internal standard, galactosamine, was added to 100 micro L of plasma containing GlcN followed by precipitation of plasma proteins with acetonitrile. Evaporation of the decanted supernatant solution was accelerated by the addition of methanol. GlcN was derivatized by addition of a solution containing 1-naphthyl isothiocyanate. Sample cleanup included passage through an anion exchange cartridge. Analysis was accomplished by injection of 0.1 mL of the sample solution into an isocratic HPLC system consisting of a C18 column, a mobile phase of acetonitrile: water: acetic acid: triethylamine (4.5: 95.5:0.1:0.05), a flow rate of 0.9 mL/min, and a UV detector set at 254 nm. Galactosamine and GlcN appeared 26 and 29 min post-injection, respectively. The assay was linear over the range of 1.25-400 micro g/mL (CV<10%) with a detection limit of 0.63 microg/mL and a limit of quantification of 1.25 microg/mL. The method was applied to the determination of GlcN in rat plasma after oral administration of 350 mg/kg of GlcN hydrochloride. The present assay is specific, sensitive, precise, and accurate and is suitable for pharmacokinetic studies.

Pyrolysis gas chromatographic atomic emission detection for sediments, coals and other petrochemical precursors

Energy Technology Data Exchange (ETDEWEB)

Seeley, J.A.; Zeng, Y.D.; Uden, P.C.; Eglinton, T.I.; Ericson, I. (Massachusetts University, Amherst, MA (USA). Dept. of Chemistry)

1992-09-01

On-line flash pyrolysis coupled to a capillary gas chromatograph for the characterization of marine sediments, coals and other heterogeneous solid samples is described. A helium microwave-induced plasma is used for chromatographic detection by atomic emission spectrometry. Simultaneous multi-element detection is achieved with a photodiode array detector. The optical path of the gas chromatographic atomic emission detector is purged with helium, allowing simultaneous, sensitive detection of atomic emission from sulfur 181 nm, phosphorous 186 nm, arsenic 189 nm, selenium 196 nm and carbon 193 nm. Several sediment and coal samples have been analysed for their carbon, nitrogen, sulfur, oxygen, phosphorous, arsenic and selenium content. Qualitative information indicating the occurrence and distribution of these elements in the samples can be used to gauge the relative stage of diagenetic evolution of the samples and provide information on their depositional environment. In some instances the chromatographic behaviour of the compounds produced upon pyrolysis is improved through on-line alkylation. This on-line derivatization is achieved by adding liquid reagents to the pyrolysis probe or by adding liquid reagents to the pyrolysis probe or by adding solid reagents either to the solid sample or by packing the reagent in the injection port of the chromatograph.

Determination of solute descriptors by chromatographic methods

International Nuclear Information System (INIS)

Poole, Colin F.; Atapattu, Sanka N.; Poole, Salwa K.; Bell, Andrea K.

2009-01-01

The solvation parameter model is now well established as a useful tool for obtaining quantitative structure-property relationships for chemical, biomedical and environmental processes. The model correlates a free-energy related property of a system to six free-energy derived descriptors describing molecular properties. These molecular descriptors are defined as L (gas-liquid partition coefficient on hexadecane at 298 K), V (McGowan's characteristic volume), E (excess molar refraction), S (dipolarity/polarizability), A (hydrogen-bond acidity), and B (hydrogen-bond basicity). McGowan's characteristic volume is trivially calculated from structure and the excess molar refraction can be calculated for liquids from their refractive index and easily estimated for solids. The remaining four descriptors are derived by experiment using (largely) two-phase partitioning, chromatography, and solubility measurements. In this article, the use of gas chromatography, reversed-phase liquid chromatography, micellar electrokinetic chromatography, and two-phase partitioning for determining solute descriptors is described. A large database of experimental retention factors and partition coefficients is constructed after first applying selection tools to remove unreliable experimental values and an optimized collection of varied compounds with descriptor values suitable for calibrating chromatographic systems is presented. These optimized descriptors are demonstrated to be robust and more suitable than other groups of descriptors characterizing the separation properties of chromatographic systems.

Determination of solute descriptors by chromatographic methods.

Science.gov (United States)

Poole, Colin F; Atapattu, Sanka N; Poole, Salwa K; Bell, Andrea K

2009-10-12

The solvation parameter model is now well established as a useful tool for obtaining quantitative structure-property relationships for chemical, biomedical and environmental processes. The model correlates a free-energy related property of a system to six free-energy derived descriptors describing molecular properties. These molecular descriptors are defined as L (gas-liquid partition coefficient on hexadecane at 298K), V (McGowan's characteristic volume), E (excess molar refraction), S (dipolarity/polarizability), A (hydrogen-bond acidity), and B (hydrogen-bond basicity). McGowan's characteristic volume is trivially calculated from structure and the excess molar refraction can be calculated for liquids from their refractive index and easily estimated for solids. The remaining four descriptors are derived by experiment using (largely) two-phase partitioning, chromatography, and solubility measurements. In this article, the use of gas chromatography, reversed-phase liquid chromatography, micellar electrokinetic chromatography, and two-phase partitioning for determining solute descriptors is described. A large database of experimental retention factors and partition coefficients is constructed after first applying selection tools to remove unreliable experimental values and an optimized collection of varied compounds with descriptor values suitable for calibrating chromatographic systems is presented. These optimized descriptors are demonstrated to be robust and more suitable than other groups of descriptors characterizing the separation properties of chromatographic systems.

A Pilot Stability Study of Dehydroepiandrosterone Rapid-dissolving Tablets Prepared by Extemporaneous Compounding.

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Rush, Steven D; Vernak, Charlene; Zhao, Fang

2017-01-01

Dehydroepiandrosterone supplementation is used to treat a variety of conditions. Rapid-dissolving tablets are a relatively novel choice for compounded dehydroepiandrosterone dosage forms. While rapid-dissolving tablets offer ease of administration, there are uncertainties about the physical and chemical stability of the drug and dosage form during preparation and over long-term storage. This study was designed to evaluate the stability of dehydroepiandrosterone rapid-dissolving tablets just after preparation and over six months of storage. The Professional Compounding Centers of America rapid-dissolving tablet mold and base formula were used to prepare 10-mg strength dehydroepiandrosterone rapid-dissolving tablets. The formulation was heated at 100°C to 110°C for 30 minutes, released from the mold, and cooled at room temperature for 30 minutes. The resulting rapid-dissolving tablets were individually packaged in amber blister packs and stored in a stability chamber maintained at 25°C and 60% relative humidity. The stability samples were pulled at pre-determined time points for evaluation, which included visual inspection, tablet weight check, United States Pharmacopeia disintegration test, and stability-indicating high-performance liquid chromatography. The freshly prepared dehydroepiandrosterone rapiddissolving tablets exhibited satisfactory chemical and physical stability. Time 0 samples disintegrated within 40 seconds in water kept at 37°C. The high-performance liquid chromatographic results confirmed that the initial potency was 101.9% of label claim and that there was no chemical degradation from the heating procedure. Over six months of storage, there were no significant changes in visual appearance, physical integrity, or disintegration time for any of the stability samples. The high-performance liquid chromatographic results also indicated that dehydroepiandrosterone rapid-dissolving tablets retained >95% label claim with no detectable degradation

Fiber-based monolithic columns for liquid chromatography.

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Ladisch, Michael; Zhang, Leyu

2016-10-01

Fiber-based monoliths for use in liquid chromatographic separations are defined by columns packed with aligned fibers, woven matrices, or contiguous fiber structures capable of achieving rapid separations of proteins, macromolecules, and low molecular weight components. A common denominator and motivating driver for this approach, first initiated 25 years ago, was reducing the cost of bioseparations in a manner that also reduced residence time of retained components while achieving a high ratio of mass to momentum transfer. This type of medium, when packed into a liquid chromatography column, minimized the fraction of stagnant liquid and resulted in a constant plate height for non-adsorbing species. The uncoupling of dispersion from eluent flow rate enabled the surface chemistry of the stationary phase to be considered separately from fluid transport phenomena and pointed to new ways to apply chemistry for the engineering of rapid bioseparations. This paper addresses developments and current research on fiber-based monoliths and explains how the various forms of this type of chromatographic stationary phase have potential to provide new tools for analytical and preparative scale separations. The different stationary phases are discussed, and a model that captures the observed constant plate height as a function of mobile phase velocity is reviewed. Methods that enable hydrodynamically stable fiber columns to be packed and operated over a range of mobile phase flow rates, together with the development of new fiber chemistries, are shown to provide columns that extend the versatility of liquid chromatography using monoliths, particularly at the preparative scale. Graphical Abstract Schematic representation of a sample mixture being separated by a rolled-stationary phase column, resulting separated peaks shown in the chromatogram.

Determination of drugs in biological fluids by direct injection of samples for liquid-chromatographic analysis.

Science.gov (United States)

Mullett, Wayne M

2007-03-10

The analysis of drugs in various biological fluids is an important criterion for the determination of the physiological performance of a drug. After sampling of the biological fluid, the next step in the analytical process is sample preparation. The complexity of biological fluids adds to the challenge of direct determination of the drug by chromatographic analysis, therefore demanding a sample preparation step that is often time-consuming, tedious, and frequently overlooked. However, direct on-line injection methods offer the advantage of reducing sample preparation steps and enabling effective pre-concentration and clean-up of biological fluids. These procedures can be automated and therefore reduce the requirements for handling potentially infectious biomaterial, improve reproducibility, and minimize sample manipulations and potential contamination. The objective of this review is to present an overview of the existing literature with emphasis on advances in automated sample preparation methods for liquid-chromatographic methods. More specifically, this review concentrates on the use of direct injection techniques, such as restricted-access materials, turbulent-flow chromatography and other automated on-line solid-phase extraction (SPE) procedures. It also includes short overviews of emerging automated extraction-phase technologies, such as molecularly imprinted polymers, in-tube solid-phase micro-extraction, and micro-extraction in a packed syringe for a more selective extraction of analytes from complex samples, providing further improvements in the analysis of biological materials. Lastly, the outlook for these methods and potential new applications for these technologies are briefly discussed.

Quantitative determination of 14C(-)-epicatechin and 14C-rutin on the Uncaria plant by a two-step heterogeneous thin-layer chromatographic-liquid scintillation counting procedure

International Nuclear Information System (INIS)

Das, N.P.; Law, K.H.

1987-01-01

A simple, rapid, precise and relatively inexpensive thin-layer chromatographic method coupled to heterogeneous liquid scintillation counting procedure was used for the quantitation of radioactivity of biologically synthesized ( 14 C) flavonoids and other phenolic plant constituents. The two flavonoids, namely ( 14 C) rutin and ( 14 C) (-) -epicatechin, extracted from the plant Uncaria elliptica Roxb were separated on plastic thin-layer plates coated with silica gel using the two solvent systems : acetonitrile-acetic acid-water (8.5:0.5:1.5) and ethyl acetate-acetic acid-water (3:1:3). The respective spots on the plates that corresponded to the two flavonoids were cut out and eluted with 3 ml aliquots of methanol followed by direct addition of scintillation flour. This method gave 99 +- 2 per cent of the total count indicating the excellent elution procedure. The results were reproducible and showed linearity over the range of 0 - 35000 dpm. The elution efficiency by several other organic solvents were also investigated. (author). 19 refs., 4 tables

Validation of a high-performance liquid chromatographic method with UV detection for the determination of ethopabate residues in poultry liver.

Science.gov (United States)

Granja, Rodrigo H M M; Niño, Alfredo M Montes; Zucchetti, Roberto A M; Niño, Rosario E Montes; Salerno, Alessandro G

2008-01-01

Ethopabate is frequently used in the prophylaxis and treatment of coccidiosis in poultry. Residues of this drug in food present a potential risk to consumers. A simple, rapid, and sensitive column high-performance liquid chromatographic (HPLC) method with UV detection for determination of ethopabate in poultry liver is presented. The drug is extracted with acetonitrile. After evaporation, the residue is dissolved with an acetone-hexane mixture and cleaned up by solid-phase extraction using Florisil columns. The analyte is then eluted with methanol. LC analysis is carried out on a C18 5 microm Gemini column, 15 cm x 4.6 mm. Ethopabate is quantified by means of UV detection at 270 nm. Parameters such as decision limit, detection capability, precision, recovery, ruggedness, and measurement uncertainty were calculated according to method validation guidelines provided in 2002/657/EC and ISO/IEC 17025:2005. Decision limit and detection capability were determined to be 2 and 3 microg/kg, respectively. Average recoveries from poultry samples fortified with 10, 15, and 20 microg/kg levels of ethopabate were 100-105%. A complete statistical analysis was performed on the results obtained, including an estimation of the method uncertainty. The method is to be implemented into Brazil's residue monitoring and control program for ethopabate.

Direct coupling of a dense (supercritical) gas chromatograph to a mass spectrometer using a supersonic molecular beam interface

International Nuclear Information System (INIS)

Randall, L.G.; Wahrhaftig, A.L.

1981-01-01

A detecting mass spectrometer has been successfully coupled to a dense gas (supercritical fluid) chromatograph to produce an instrument (DGC/MS) that may be an alternative to high performance liquid chromatograph/mass spectrometer instruments (HPLC/MS) and gas chromatograph/mass spectrometer instruments (GC/MS) for analysis of involatile and/or thermally labile compounds. The mobile phase in DGC is a gas held at temperatures above the critical temperature and at pressures sufficient to obtain nearly liquid-like densities. DGC combines advantages of GC and HPLC: rapid separations, moderate operating temperatures, and analysis of involatile compounds. An advantage unique to DGC is the solvent power dependence upon pressure. While several groups have studied DGC, its development has been limited by the lack of a sensitive and selective detector. Hence, work has been directed towards the design and construction of a DGC/MS resulting in a trial instrument capable of chromatographic pressures of at least 300 atm and temperatures from 10 0 to 60 0 C. The DGC/MS coupling has been accomplished by the use of a supersonic molecular beam interface. This application of molecular beam formation appears to be unique in its requirements of a large pressure ratio (approx.10 8 ), low flow rates, and low final pressures. The authors outline characteristics of supersonic jets and molecular beams pertinent to the design of such an instrument. The interface which uses pumping speeds of 2400 and 1200 l/s in the beam forming chambers is described in detail, while the other components: the detecting mass spectrometer, the dense gas supply, and the DGC: are briefly described. Preliminary work with this instrument has established the feasibility of DGC/MS as an analytical technique and further development is recommended

Development of liquid chromatographic methods for the determination of phytosterols in Standard Reference Materials containing saw palmetto.

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Bedner, Mary; Schantz, Michele M; Sander, Lane C; Sharpless, Katherine E

2008-05-23

Liquid chromatographic (LC) methods using atmospheric pressure chemical ionization/mass spectrometric (APCI-MS) detection were developed for the separation and analysis of the phytosterols campesterol, cycloartenol, lupenone, lupeol, beta-sitosterol, and stigmasterol. Brassicasterol and cholesterol were also included for investigation as internal standards. The methods were used to identify and quantify the phytosterols in each of two Serenoa repens (saw palmetto) Standard Reference Materials (SRMs) developed by the National Institute of Standards and Technology (NIST). Values obtained by LC-MS were compared to those obtained using the more traditional approach of gas chromatography with flame ionization detection. This is the first reported use of LC-MS to determine phytosterols in saw palmetto dietary supplement materials.

High performance liquid chromatographic determination of vanadium in crude oils and cobalt and iron in pharmaceutical preparations

International Nuclear Information System (INIS)

Khuhawar, M.Y.; Lanjwani, S.N.; Khaskhely, G.Q.

1993-01-01

High performance liquid Chromatographic (HPLC) method has ben developed for the determination of vanadium in crude oils, based on acid decomposition of oils, followed by complexation with bis (salicylaldehyde) tetramethyl ethylenediamine (H2SA2Ten). The complex is extracted in organic phase and is separated from copper and nickel using normal phase HPLC column. Detection is achieved using spectrophtmetric detector. The vanadium in oil is obtained at sub microgram/g level. Similarly cobalt(II), cobalt(III) and iron(II) are separated on reversed phase HPLC column. Pre column derivatization is used to develop HPLC method for the determination of cobalt and iron in pharmaceutical preparations. Finally results are compared using atomic absorption spectrometer. (author)

High performance liquid chromatographic hydrocarbon group-type analyses of mid-distillates employing fuel-derived fractions as standards

Science.gov (United States)

Seng, G. T.; Otterson, D. A.

1983-01-01

Two high performance liquid chromatographic (HPLC) methods have been developed for the determination of saturates, olefins and aromatics in petroleum and shale derived mid-distillate fuels. In one method the fuel to be analyzed is reacted with sulfuric acid, to remove a substantial portion of the aromatics, which provides a reacted fuel fraction for use in group type quantitation. The second involves the removal of a substantial portion of the saturates fraction from the HPLC system to permit the determination of olefin concentrations as low as 0.3 volume percent, and to improve the accuracy and precision of olefins determinations. Each method was evaluated using model compound mixtures and real fuel samples.

Correlations between chromatographic parameters and bioactivity predictors of potential herbicides.

Science.gov (United States)

Janicka, Małgorzata

2014-08-01

Different liquid chromatography techniques, including reversed-phase liquid chromatography on Purosphere RP-18e, IAM.PC.DD2 and Cosmosil Cholester columns and micellar liqud chromatography with a Purosphere RP-8e column and using buffered sodium dodecyl sulfate-acetonitrile as the mobile phase, were applied to study the lipophilic properties of 15 newly synthesized phenoxyacetic and carbamic acid derivatives, which are potential herbicides. Chromatographic lipophilicity descriptors were used to extrapolate log k parameters (log kw and log km) and log k values. Partitioning lipophilicity descriptors, i.e., log P coefficients in an n-octanol-water system, were computed from the molecular structures of the tested compounds. Bioactivity descriptors, including partition coefficients in a water-plant cuticle system and water-human serum albumin and coefficients for human skin partition and permeation were calculated in silico by ACD/ADME software using the linear solvation energy relationship of Abraham. Principal component analysis was applied to describe similarities between various chromatographic and partitioning lipophilicities. Highly significant, predictive linear relationships were found between chromatographic parameters and bioactivity descriptors. © The Author [2013]. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Chromatographic analysis and purification of multiply tritium-labelled eicosanoids

International Nuclear Information System (INIS)

Shevchenko, V.P.; Nagaev, I.Yu.; Myasoedov, N.F.

1988-01-01

A comparative study of different chromatographic techniques (gas-liquid (GLC), thin-layer (TLC), liquid (LC), high-pressure liquid (HPLC) chromatography) is presented. They were applied to the analysis and preparative purification of tritium-labelled eicosanoids with a molar radioactivity of 1.8-8.8 TBq/mmol, obtained by selective hydrogenation and by chemical or enzymic methods. The possibility of analyzing reaction mixtures and isolating individual multiply labelled eicosanoids with a chemical and radiochemical purity of 95-98% was demonstrated. Special features of HPLC for high molar radioactivity eicosanoids are considered. (author) 9 refs.; 6 tabs

Liquid-chromatographic analysis for cyclosporine with use of a microbore column and small sample volume.

Science.gov (United States)

Annesley, T; Matz, K; Balogh, L; Clayton, L; Giacherio, D

1986-07-01

This liquid-chromatographic assay requires 0.2 to 0.5 mL of whole blood, avoids the use of diethyl ether, and consumes only 10 to 20% of the solvents used in prior methods. Sample preparation involves an acidic extraction with methyl-t-butyl ether, performed in a 13 X 100 mm disposable glass tube, then a short second extraction of the organic phase with sodium hydroxide. After evaporation of the methyl-t-butyl ether, chromatography is performed on an "Astec" 2.0-mm (i.d.) octyl column. We compared results by this procedure with those by use of earlier larger-scale extractions and their respective 4.6-mm (i.d.) columns; analytical recoveries of cyclosporins A and D were comparable with previous findings and results for patients' specimens were equivalent, but the microbore columns provided greatly increased resolution and sensitivity.

High performance liquid chromatographic separation of polycyclic aromatic hydrocarbons on microparticulate pyrrolidone and application to the analysis of shale oil

International Nuclear Information System (INIS)

Mourey, T.H.; Siggia, S.; Uden, P.C.; Crowley, R.J.

1980-01-01

A chemically bonded pyrrolidone substrate is used for the high performance liquid chromatographic separation of polycyclic aromatic hydrocarbons. The cyclic amide phase interacts electronically with the polycyclic aromatic hydrocarbons in both the normal and reversed phase modes. Separation is effected according to the number of aromatic rings and the type of ring condensation. Information obtained is very different from that observed on hydrocarbon substrates, and thus these phases can be used in a complementary fashion to give a profile of polycyclic aromatics in shale oil samples. 7 figures, 1 table

Ion-pair high performance liquid chromatographic retention behavior of salicylic acid and its derivatives

Energy Technology Data Exchange (ETDEWEB)

Lee, K.W.; Chung, Y.S. [Chungbuk National University, Cheongju (Korea); Oh, S.K. [Handok Pharmaceuticals Co. Ltd., Chungbuk (Korea)

1999-06-01

The ion-pair high performance liquid chromatographic elution behavior of salicylic acid and its derivatives was studied with measuring capacity factor, k', changing the concentration of ion-pairing reagent (tetrabutylammonium chloride, TBACl) in mobile phase. As a result, it was found that k' of the samples increase at pH 7.2 as the TBACl concentration increase. The derivatives of salicylic acid were separated each other at an optimum mobile phase condition which was found from the observation of the retention behavior. The optimum mobile phase condition was methanol solution(MeOH:H{sub 2}O 30:70) containing 20 mM TBACl for the determination of salicylic acid and methanol solution (MeOH:H{sub 2}O 20:80) containing 40 mM TBACl for p-aminosalicylic acid at pH 7.2. The method has been applied for the analysis of the contents of salicylic acid derivatives in an aspirin tablet and a tuberculosis curing agent. 8 refs., 4 figs., 2 tabs.

Detection of irradiated fruits and vegetables by gas-chromatographic methods and electron spin-resonance

Energy Technology Data Exchange (ETDEWEB)

Farag, S.E.A. (National Centre for Radiation Research and Technology, Cairo (Egypt))

1993-01-01

Gas chromatographic methods detected some hydrocarbons esp. 17:1, 16:2, 15:0 and 14:1 in irradiated, Avocado, Papaya, Mangoes with 0.75, 1.5, 3.0 kGy and Apricot with 0.5 and 3.0 kGy. The detection of hydrocarbons was clearly at high doses but the low doses need more sensitive conditions using Liquid-Liquid-Gas chromatographic method as used here. Using Electron Spin-Resonance, produce a specific signal from irradiated onion (dried leaves) as well as apricot (hard coat of kernels) after some weeks of irradiation process but not clear with the other foodstuffs. (orig.)

Quantification of rifampicin in human plasma and cerebrospinal fluid by a highly sensitive and rapid liquid chromatographic-tandem mass spectrometric method.

Science.gov (United States)

Srivastava, Abhishek; Waterhouse, David; Ardrey, Alison; Ward, Stephen A

2012-11-01

A highly sensitive and rapid liquid chromatography tandem mass spectrometry (LC-MS/MS) method has been developed to measure the levels of the antitubercular drug rifampicin (RIF) in human plasma and cerebrospinal fluid (CSF). The analyte and internal standard (IS) were isolated from plasma and CSF by a simple organic solvent based precipitation of proteins followed by centrifugation. Detection was carried out by electrospray positive ionization mass spectrometry in the multiple-reaction monitoring (MRM) mode. The assay was linear in the concentration range 25-6400 ng/mL with intra- and inter-day precision of <7% and <8%, respectively. The validated method was applied to the study of RIF pharmacokinetics in human CSF and plasma over 25 h period after a 10 mg/kg oral dose. Copyright © 2012 Elsevier B.V. All rights reserved.

Liquid chromatographic determination of seven antioxidants in dry food.

Science.gov (United States)

Page, B D; Charbonneau, C F

1989-01-01

The liquid chromatographic determinative step of the official method for propyl gallate, trihydroxybutyrophenone, tert-butylhydroquinone, nordihydroguaiaretic acid, butylated hydroxyanisole (BHA), 3,5-di-tert-butyl-4-hydroxymethylphenol, and butylated hydroxytoluene (BHT) in fats and oils has been applied to their determination in a number of dry foods. A representative sample (10 g) is homogenized first with hexane (25 mL), then with 5 mL added water, and finally with 75 mL added acetonitrile. The hexane and acetonitrile are decanted, filtered, and separated; the hexane and rehydrated food are reextracted with 2 additional portions of acetonitrile, and the combined acetonitrile extracts are concentrated and diluted to 10 mL. An aliquot is analyzed as described in the official method, using a 150 x 4.6 mm 5 microns C-18 column. The need for rehydration to maximize the recovery of BHA and other antioxidants from marketplace dry food samples such as potato flakes, dry coffee whiteners, and dessert topping mixes was demonstrated. Rehydration was not required for cheese snacks, breakfast cereals, cake mixes, and some other foods. The need for rehydration should be determined by analyzing other foods with and without the addition of water. Potato and corn chips, popcorn and cheese snacks, breakfast cereals, dry beverage mixes, rice, potato flakes, french fried potatoes, and cake mixes were spiked with the above antioxidants at 10-50 ppm. Overall recoveries ranged from 64.3 to 105.6% and repeatabilities ranged from 0.7 to 10.8%. A total of 109 samples of the above foods were analyzed, and 64% contained detectable (greater than 1-2 ppm) antioxidants, mainly BHA and BHT.

Rapid Screening and Characterization of Acetylcholinesterase Inhibitors from Yinhuang Oral Liquid Using Ultrafiltration-liquid Chromatography-electrospray Ionization Tandem Mass Spectrometry.

Science.gov (United States)

Zhang, Haomin; Guo, Yinan; Meng, Lingwen; Sun, Hui; Yang, Yinping; Gao, Ying; Sun, Jiaming

2018-01-01

At present, approximately 17-25 million people in the world suffer from Alzheimer's disease (AD). The most efficacious and acceptable therapeutic drug clinically are the acetylcholinesterase inhibitors (AChEIs). Yinhuang oral liquid is a Chinese medicine preparation which contains AChEIs according to the literatures. However, no strategy has been presented for rapid screening and identification of AChEIs from Yinhuang oral liquid. To develop a method for rapid screening and identification of AChEIs from Yinhuang oral liquid using ultrafiltration-liquid chromatography-electrospray ionization tandem mass spectrometry (UF-LC-ESI-MS/MS). In this study, UF incubation conditions such as enzyme concentration, incubation time, and incubation temperature were optimized so as to get better screening results. The AChEIs from Yinhuang oral liquid were identified by high-performance liquid chromatography-ESI-MS and the improved Ellman method was used for the AChE inhibitory activity test in vitro . The results showed that Yinhuang oral liquid can inhibit the activity of AChE. We screened and identified seven compounds with potential AChE inhibitory activity from Yinhuang oral liquid, which provided experimental basis for the treatment and prevention of AD. The current technique was used to directly screen the active ingredients with acetylcholinesterase inhibition from complex traditional Chinese medicine, which was simple, rapid, accurate, and suitable for high-throughput screening of AChEI from complex systems. A UF-LC-ESI-MS/MS method for rapid screening and identification of AChEIs from Yinhuang oral liquid was developedSeven compounds were screened and identified with potential AChE inhibitory activity from Yinhuang oral liquidIt provided experimental basis of Yinhuang oral liquid for the treating and preventing AD. Abbreviations used: (AD): Alzheimer's disease; (UF-LC-ESI-MS/MS): ultrafiltration-liquid chromatography-electrospray ionization tandem mass spectrometry; (ACh

Rapid Screening and Characterization of Acetylcholinesterase Inhibitors from Yinhuang Oral Liquid Using Ultrafiltration-liquid Chromatography-electrospray Ionization Tandem Mass Spectrometry

Science.gov (United States)

Zhang, Haomin; Guo, Yinan; Meng, Lingwen; Sun, Hui; Yang, Yinping; Gao, Ying; Sun, Jiaming

2018-01-01

Background: At present, approximately 17–25 million people in the world suffer from Alzheimer's disease (AD). The most efficacious and acceptable therapeutic drug clinically are the acetylcholinesterase inhibitors (AChEIs). Yinhuang oral liquid is a Chinese medicine preparation which contains AChEIs according to the literatures. However, no strategy has been presented for rapid screening and identification of AChEIs from Yinhuang oral liquid. Objective: To develop a method for rapid screening and identification of AChEIs from Yinhuang oral liquid using ultrafiltration–liquid chromatography–electrospray ionization tandem mass spectrometry (UF-LC-ESI-MS/MS). Materials and Methods: In this study, UF incubation conditions such as enzyme concentration, incubation time, and incubation temperature were optimized so as to get better screening results. The AChEIs from Yinhuang oral liquid were identified by high-performance liquid chromatography-ESI-MS and the improved Ellman method was used for the AChE inhibitory activity test in vitro. Results: The results showed that Yinhuang oral liquid can inhibit the activity of AChE. We screened and identified seven compounds with potential AChE inhibitory activity from Yinhuang oral liquid, which provided experimental basis for the treatment and prevention of AD. Conclusion: The current technique was used to directly screen the active ingredients with acetylcholinesterase inhibition from complex traditional Chinese medicine, which was simple, rapid, accurate, and suitable for high-throughput screening of AChEI from complex systems. SUMMARY A UF-LC-ESI-MS/MS method for rapid screening and identification of AChEIs from Yinhuang oral liquid was developedSeven compounds were screened and identified with potential AChE inhibitory activity from Yinhuang oral liquidIt provided experimental basis of Yinhuang oral liquid for the treating and preventing AD. Abbreviations used: (AD): Alzheimer's disease; (UF

Rapid process development of chromatographic process using direct analysis in real time mass spectrometry as a process analytical technology tool.

Science.gov (United States)

Yan, Binjun; Chen, Teng; Xu, Zhilin; Qu, Haibin

2014-06-01

The concept of quality by design (QbD) is widely applied in the process development of pharmaceuticals. However, the additional cost and time have caused some resistance about QbD implementation. To show a possible solution, this work proposed a rapid process development method, which used direct analysis in real time mass spectrometry (DART-MS) as a process analytical technology (PAT) tool for studying the chromatographic process of Ginkgo biloba L., as an example. The breakthrough curves were fast determined by DART-MS at-line. A high correlation coefficient of 0.9520 was found between the concentrations of ginkgolide A determined by DART-MS and HPLC. Based on the PAT tool, the impacts of process parameters on the adsorption capacity were discovered rapidly, which showed a decreased adsorption capacity with the increase of the flow rate. This work has shown the feasibility and advantages of integrating PAT into QbD implementation for rapid process development. Copyright © 2014 Elsevier B.V. All rights reserved.

Rapid Analysis of Apolar Low Molecular Weight Constituents in Wood Using High Pressure Liquid Chromatography with Evaporative Light Scattering Detection

NARCIS (Netherlands)

Claassen, F.W.; Haar, van de C.; Beek, van T.A.; Dorado, J.; Martinez-Inigo, M.; Sierra-Alvarez, R.

2000-01-01

A new high pressure liquid chromatographic method with evaporative light scattering detection was developed for the qualitative and quantitative analysis of apolar, low molecular weight constituents in wood. The wood extractives were obtained by means of a 6 h Soxhlet extraction with acetone. The

Miniaturized chromatographic radiochemical procedure for 131I - MIBG

International Nuclear Information System (INIS)

Barboza, M.F. de; Pereira, N.S. de; Colturato, M.T.; Silva, C.P.G. da.

1989-12-01

Different solvents were used in paper chromatographic methods to obtain the best system in routine radiochemical control for 131 I-MIBG produced at IPEN-CNEN/SP. The dates were compared with those obtained with eletrophoresis method in buffer acetate, pH=4.5, 350V, during 40 minutes. The stability of the labeled compound store under 4 0 C was studied during 15 days. Miniaturized chromatographic procedures were established using Whatman 3MM (8x1cm) and n-butanol-:acetic acid: water (S:2:1) as a solvent. the Rf values were: 0.3 (I - ) and 1.0 (MIBG). The radiochemical purity was 99.3 and 99.2% (first day) obtained with eletrophoresis and miniaturized chromatographic procedures, respectively and, 84.7% after 15 days of its preparation. It is a rapid, practical and reproductive method. (author) [pt

Impurity analysis in EC-99mTC radiotracer using chromatographic techniques

International Nuclear Information System (INIS)

Almeida, E.V.; Fukumori, N.T.O.; Mengatti, J.; Silva, C.P.G.; Matsuda, M.M.N.

2008-01-01

The objective of this study was to develop two chromatographic methods of impurity analysis in radiotracer 99m Tc-EC: the Thin Layer Chromatography (TLC) and the High Performance Liquid Chromatography Reversed Phase (HPLC-RP)

Liquid Chromatographic-Chemometric Techniques for the Simultaneous HPLC Determination of Lansoprazole, Amoxicillin and Clarithromycin in Commercial Preparation.

Science.gov (United States)

Aktas, A Hakan; Saridag, Ayse Mine

2017-09-01

Two multivariate calibration-prediction techniques, principal component regression (PCR) and partial least-squares regression (PLSR) were applied to the chromatographic multicomponent analysis of the drug containing lansoprazole (LAN), clarithromycin (CLA) and amoxicillin (AMO). Optimum chromatographic separation of LAN, CLA and AMO with atorvastatin as the internal standard (IS) was obtained by using Xterra® RP18 column 5 μm 4.6 × 250 mm2, and 25 mM ammonium chloride buffer prepared ammonium chloride, acetonitrile and bidistilled water (45:45:10 v/v) as the mobile phase at flow rate 1.0 mL/min. The high pressure liquid chromatography data sets consisting of the ratios of analyte peak areas to the IS peak area were obtained by using diode array detector detection at five wavelengths (205, 210, 215, 220 and 225 nm). LC-chemometric calibration for LAN, CLA and AMO were separately constructed by using the relationship between the peak-area ratio and training sets for each analyte. A series of synthetic solutions containing different concentrations of LAN, CLA and AMO were used to check the prediction ability of the PCR and PLS. Both of the two-chemometric methods in this study can be satisfactorily used for the quantitative analysis and for dissolutions tests of multicomponent commercial drug. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

A simple subcritical chromatographic test for an extended ODS high performance liquid chromatography column classification.

Science.gov (United States)

Lesellier, Eric; Tchapla, Alain

2005-12-23

This paper describes a new test designed in subcritical fluid chromatography (SFC) to compare the commercial C18 stationary phase properties. This test provides, from a single analysis of carotenoid pigments, the absolute hydrophobicity, the silanol activity and the steric separation factor of the ODS stationary phases. Both the choice of the analytical conditions and the validation of the information obtained from the chromatographic measurements are detailed. Correlations of the carotenoid test results with results obtained from other tests (Tanaka, Engelhard, Sander and Wise) performed both in SFC and HPLC are discussed. Two separation factors, calculated from the retention of carotenoid pigments used as probe, allowed to draw a first classification diagram. Columns, which present identical chromatographic behaviors are located in the same area on this diagram. This location can be related to the stationary phase properties: endcapping treatments, bonding density, linkage functionality, specific area or silica pore diameter. From the first classification, eight groups of columns are distinguished. One group of polymer coated silica, three groups of polymeric octadecyl phases, depending on the pore size and the endcapping treatment, and four groups of monomeric stationary phases. An additional classification of the four monomeric groups allows the comparison of these stationary phases inside each group by using the total hydrophobicity. One hundred and twenty-nine columns were analysed by this simple and rapid test, which allows a comparison of columns with the aim of helping along their choice in HPLC.

Rapid validated liquid chromatographic method coupled with ...

African Journals Online (AJOL)

NTB in human plasma, and thus can be applied efficiently for the analysis of clinical samples containing. NTB. Keywords: ... permits the analysis of a lot of clinical samples containing NTB in a ... from Milli-Q plus purification system, Millipore, ... Fifty microliter of CBP working standard solution ... Percentage relative error (%.

Rapid chromatographic separation of dissoluble Ag(I) and silver-containing nanoparticles of 1-100 nanometer in antibacterial products and environmental waters.

Science.gov (United States)

Zhou, Xiao-Xia; Liu, Rui; Liu, Jing-Fu

2014-12-16

Sensitive and rapid methods for speciation analysis of nanoparticulate Ag (NAg) and Ag(I) in complex matrices are urgently needed for understanding the environmental effects and biological toxicity of silver nanoparticles (AgNPs). Herein we report the development of a universal liquid chromatography (LC) method for rapid and high resolution separation of dissoluble Ag(I) from nanoparticles covering the entire range of 1-100 nm in 5 min. By using a 500 Å poresize amino column, and an aqueous mobile phase containing 0.1% (v/v) FL-70 (a surfactant) and 2 mM Na2S2O3 at a flow rate of 0.7 mL/min, all the nanoparticles of various species such as Ag and Ag2S were eluted in one fraction, while dissoluble Ag(I) was eluted as a baseline separated peak. The dissoluble Ag(I) was quantified by the online coupled ICP-MS with a detection limit of 0.019 μg/L. The NAg was quantified by subtracting the dissoluble Ag(I) from the total Ag content, which was determined by ICP-MS after digestion of the sample without LC separation. While the addition of FL-70 and Na2S2O3 into the mobile phase is essential to elute NAg and Ag(I) from the column, the use of 500 Å poresize column is the key to baseline separation of Ag(I) from ∼ 1 nm AgNPs. The feasibility of the proposed method was demonstrated in speciation analysis of dissoluble Ag(I) and NAg in antibacterial products and environmental waters, with very good chromatographic repeatability (relative standard deviations) in both peak area (<2%) and retention time (<0.6%), excellent spiked recoveries in the range of 84.7-102.7% for Ag(I) and 81.3-106.3% for NAg. Our work offers a novel approach to rapid and baseline separation of dissoluble metal ions from their nanoparticulate counterparts covering the whole range of 1-100 nm.

Radioactivity monitor for high-performance liquid chromatography

International Nuclear Information System (INIS)

Reeve, D.R.; Crozier, A.

1977-01-01

The coupling of a homogeneous radioactivity monitor to a liquid chromatograph involves compromises between the sensitivity of the monitor and the resolution and speed of analysis of the chromatograph. The theoretical relationships between these parameters are considered and expressions derived which make it possible to calculate suitable monitor operating conditions for most types of high-performance liquid chromatography

General and selective isolation procedure for high-performance liquid chromatographic determination of anabolic steroids in tissues.

Science.gov (United States)

Laganà, A; Marino, A

1991-12-27

A multi-residue method has been developed for the determination of anabolic steroids in animal tissue. The analytes are extracted from tissue with methanol and the extract is subjected to two solid-phase extractions, one using a non-specific adsorbing material, such as graphitized carbon black (Carbopack B), and the other Amberlite CG-400 I in the OH form. This procedure allowed the neutral anabolics (testosterone, trenbolone and progesterone) to be isolated and separated from the acidic type (phenolic group), such as diethylstilbestrol, oestradiol, zeranol/zearalenone and their respective metabolites. The determination was effected using high-performance liquid chromatography with different detectors (ultraviolet, fluorimetric and electrochemical). Several analytical parameters were studied: chromatographic conditions, recoveries, evaporation step, solvent flow-rate, cartridges reusability, interference of plastic cartridges. For all the anabolics investigated the recoveries were greater than 83.6%.

Method for chromatographically recovering scandium and yttrium

International Nuclear Information System (INIS)

Snyder, T.S.; Stoltz, R.A.

1991-01-01

This paper describes a method for chromatographically recovering scandium and yttrium from the residue of a sand chlorinator. It comprises: providing a residue from a sand chlorinator, the residue containing scandium, yttrium, sodium, calcium and at least one radioactive metal of the group consisting of radium, thorium and uranium; digesting the residue with an acid to produce an aqueous liquid containing scandium, yttrium, sodium, calcium and at least one radioactive metal of the group consisting of radium, thorium and uranium; feeding the metal containing liquid through a cation exchanger; eluding the cation exchanger with an acid eluant to to produce: a first eluate containing at least half of the total weight of the calcium and sodium in the feed liquid; a second eluate containing at least half of the total weight of the one or more radioactive metals in the feed liquid; a third eluate containing at least half of the yttrium in the feed liquid, and a fourth eluate containing at least half of the weight of the scandium in the feed liquid

New liquid chromatographic-chemometric approach for the determination of sunset yellow and tartrazine in commercial preparation.

Science.gov (United States)

Dinç, Erdal; Aktaş, A Hakan; Ustündağ, Ozgür

2005-01-01

A new liquid chromatographic (LC)-chemometric approach was developed for the determination of sunset yellow (SUN) and tartrazine (TAR) in commercial preparations. This approach uses LC and chemometric calibration methods, i.e., classical least-squares (CLS), principal component regression (PCR), and partial-least squares (PLS), simultaneously. The combined LC-chemometric approaches, denoted as LC-CLS, LC-PCR, and LC-PLS, are based on photodiode array (PDA) detection at multiple wavelengths. Optimum chromatographic separation of SUN and TAR with allura red as the internal standard (IS) was obtained by using a Waters Symmetry C18 column, 5 microm, 4.6 x 250 mm, and 0.2 M acetate buffer (pH 5)-acetonitrile-methano-bidistilled water (55 + 20 + 15 + 10, v/v) as the mobile phase at a flow rate of 1.9 mL/min. The LC data sets consisting of the ratios of analyte peak areas to the IS peak area were obtained by using PDA detection at 5 wavelengths (465, 470, 475, 480, and 485 nm). LC-chemometric calibrations for SUN and TAR were separately constructed by using the relationship between the peak-area ratio and the training sets for each colorant. LC-chemometric approaches were tested for different synthetic mixtures containing SUN and TAR in the presence of the IS. These LC-chemometric calibrations were applied to a commercial preparation of the 2 colorants. The experimental results of the LC-chemometric approaches were compared with those obtained by a developed classical LC method using single-wavelength detection.

Column Liquid Chromatography.

Science.gov (United States)

Majors, Ronald E.; And Others

1984-01-01

Reviews literature covering developments of column liquid chromatography during 1982-83. Areas considered include: books and reviews; general theory; columns; instrumentation; detectors; automation and data handling; multidimensional chromatographic and column switching techniques; liquid-solid chromatography; normal bonded-phase, reversed-phase,…

Covalently coating dextran on macroporous polyglycidyl methacrylate microsphere enabled rapid protein chromatographic separation

International Nuclear Information System (INIS)

Zhang, Rongyue; Li, Qiang; Li, Juan; Zhou, Weiqing; Ye, Peili; Gao, Yang; Ma, Guanghui; Su, Zhiguo

2012-01-01

Protein denaturation and nonspecific adsorption on polymer media as a chromatographic support have been a problem which needs to be overcome. Macroporous poly(glycidyl methacrylate–divinylbezene) (PGMA–DVB) microspheres prepared in this study were firstly covalently coated with dextran through a three-step method. The dextran was firstly adsorbed onto the microspheres and then covalently bound to the PGMA–DVB microsphere through ether bonds which were formed by hydroxyl group reacting with epoxy group at the presence of 4-(Dimethylamino) pyridine. Finally, the coating dextran layer was crosslinked by ethylene glycol diglycidyl ether to form the continuous network coating. The coated microspheres were characterized by Fourier transform infrared spectra, scanning electron microscope, mercury porosimetry measurements, laser scanning confocal microscope, and protein adsorption experiments. Results showed that PGMA–DVB microspheres coated with dextran successfully maintained the macroporous structure and high permeability. The backpressure was only 1.69 MPa at a high flow rate of 2891 cm/h. Consequently, the hydrophilicity and biocompatibility of modified microspheres were greatly improved, and the contact angle decreased from 184° to 13°, and nonspecific adsorption of proteins was decreased to little or none. The clad dextran coating with large amounts of hydroxyl group was easily derived to be various functional groups. The derived media have great potential applications in rapid protein chromatography. - Highlights: ► Macroporous PGMA–DVB microspheres were covalently coated with dextran. ► The hydrophilicity of the coated microspheres was significantly improved. ► The irreversible adsorption of proteins was reduced to zero. ► The coated microspheres can maintain the macropore structure. ► The coated microspheres were applied to rapid protein separation.

High-performance Liquid Chromatographic Ultraviolet Detection of Nilotinib in Human Plasma from Patients with Chronic Myelogenous Leukemia, and Comparison with Liquid Chromatography-Tandem Mass Spectrometry.

Science.gov (United States)

Nakahara, Ryosuke; Satho, Yuhki; Itoh, Hiroki

2016-11-01

A method for determining nilotinib concentration in human plasma is proposed using high-performance liquid chromatography and ultraviolet detection. Nilotinib and the internal standard dasatinib were separated using a mobile phase of 0.5% Na 2 PO 4 H 2 O (pH 2.5)-acetonitrile-methanol (55:25:20, v/v/v) on a Capcell Pak C18 MG II column (250 × 4.6 mm) at a flow rate of 1.0 ml/min, and ultraviolet measurement at 250 nm. The calibration curve exhibited linearity over the nilotinib concentration range of 50-2,500 ng/ml at 250 nm, with relative standard deviations (n = 5) of 7.1%, 2.5%, and 2.9% for 250, 1,500, and 2,500 ng/ml, respectively. The detection limit for nilotinib was 5 ng/ml due to three blank determinations (ρ = 3). This method was successfully applied to assaying nilotinib in human plasma samples from patients with chronic myelogenous leukemia. In addition, we compared the results with those measured by liquid chromatography-tandem mass spectrometry (LC-MS/MS) at BML, Inc. (a commercial laboratory). A strong correlation was observed between the nilotinib concentrations measured by our high-performance liquid chromatographic method and those obtained by LC/MS-MS (r 2 = 0.988, P < 0.01). © 2016 Wiley Periodicals, Inc.

Ionic Liquid-Liquid Chromatography: A New General Purpose Separation Methodology

OpenAIRE

Brown, Leslie; Earle, Martyn J; Gilea, Manuela; Plechkova, Natalia V; Seddon, Kenneth R

2017-01-01

Ionic liquids can form biphasic solvent systems with many organic solvents and water, and these solvent systems can be used in liquid-liquid separations and countercurrent chromatography. The wide range of ionic liquids that can by synthesised, with specifically tailored properties, represents a new philosophy for the separation of organic, inorganic and bio-based materials. A customised countercurrent chromatograph has been designed and constructed specifically to allow the more viscous char...

Rapid-action valve especially for liquid metal

International Nuclear Information System (INIS)

Velek, V.; Cejka, J.; Jakl, J.

1976-01-01

A rapid-action large-diameter valve and control fitting was designed for cooling circuits of nuclear power plants with fast liquid metal cooled reactors, namely sodium cooled. The design meets the requirements for axial symmetry about the flow axis and secures the equilibrium of hydraulic and hydrodynamic forces observing the uniformity of the thickness of the fitting walls which is a pre-requisite for good resistance to thermal shock. (F.M.)

Rapid Determination of Bile Acids in Bile from Various Mammals by Reversed-Phase Ultra-Fast Liquid Chromatography.

Science.gov (United States)

Si, Gu Leng Ri; Yao, Peng; Shi, Luwen

2015-08-01

A valid and efficient reversed-phase ultra-fast liquid chromatography method was developed for the simultaneous determination of 13 bile acids in the bile of three mammal species, including rat, pig and human gallstone patients. Chromatographic separation was performed with a Shim-pack XR-ODS column, and the mobile phase consisted of acetonitrile and potassium phosphate buffer (pH 2.6) at a flow rate of 0.5 mL min(-1). The linear detection range of most bile acids ranged from 2 to 600 ng µL(-1) with a good correlation coefficient (>0.9995). The precision of each bile acid was bile acids were separated in 15 min with satisfactory resolution, and the total analysis time was 18 min, including equilibration. The method was successfully applied in rapid screening of bile samples from the three mammals. Significant metabolic frameworks of bile acids among various species were observed, whereas considerable quantitative variations in both inter- and intraspecies were also observed, especially for gallstone patients. Our results suggest that detecting the change of bile acid profiles could be applied for the diagnosis of gallstone disease. © Crown copyright 2014.

Gas chromatographic column for the Viking 1975 molecular analysis experiment

Science.gov (United States)

Novotny, M.; Hayes, J. M.; Bruner, F.; Simmonds, P. G.

1975-01-01

A gas chromatographic column has been developed for use in the remote analysis of the Martian surface. The column, which utilizes a liquid-modified organic adsorbent (Tenax) as the stationary phase, provides efficient transmission and resolution of nanogram quantities of organic materials in the presence of millionfold excesses of water and carbon dioxide.

Speciation of eight arsenic compounds in human urine by high performance liquid chromatography with inductively coupled plasma mass spectrometric detection using antimonate for internal chromatographic standardization

DEFF Research Database (Denmark)

Larsen, Erik Huusfeldt; Pritzl, G.; Hansen, S. H.

1993-01-01

Four anionic and four cationic arsenic compounds in urine were separated by anion- and cation-exchange high-performance liquid chromatography and detected by inductively coupled plasma mass spectrometry (ICP-MS) at m/z 75. The species were the anions arsenite, arsenate, monomethylarsonate...... and dimethylarsinate and the cations arsenobetaine, trimethylarsine oxide, arsenocholine and the tetramethylarsonium ion. Hexahydroxyantimonate(III) was co-chromatographed with the arsenic anions but detected at m/z 121 and used as an internal standard for their qualitative analysis. Arsenite was prone to oxidation....... The argon chloride interference at m/z 75 was eliminated by chromatographic separation of the chloride present in the sample from the arsenic analytes. The ClO+ ion detected at m/z 51 and 53 was used to monitor the retention time of chloride in the anion-exchange system. The chloride eluted about 100 s...

Reversed-phase liquid chromatographic profile of free amino acids in strawberry-tree (Arbutus unedo L.) honey.

Science.gov (United States)

Spano, Nadia; Piras, Irene; Ciulu, Marco; Floris, Ignazio; Panzanelli, Angelo; Pilo, Maria I; Piu, Paola C; Sanna, Gavino

2009-01-01

The typical profile of the free amino acids contained in strawberry-tree (Arbutus unedo L.) honey is reported for the first time. An optimized reversed-phase liquid chromatographic (RP-LC) method with phenyl isothiocyanate precolumn derivatization was used. Fourteen free amino acids were identified and quantified in 16 analytical samples. Proline (65.63%) was found to be the most abundant free amino acid, followed by glutamic acid (6.49%), arginine (5.21%), alanine (5.17%), and phenylalanine (4.97%). The total free amino acid content of strawberry-tree honey (average value, 436 mg/kg) was found to be low in comparison to amounts cited in the literature concerning unifloral honeys. The analytical method was optimized and fully validated in terms of detection and quantitation limits, precision (by testing repeatability and reproducibility), linearity, and bias (by means of recovery tests). The acceptability of the validation protocol results was verified using Horwitz's mathematical model and AOAC guidelines.

High-performance liquid chromatographic assay for two rifamycin-derived hypocholesterolemic agents in liver and biological fluids.

Science.gov (United States)

Moore, D J; Perrino, P J; Klerer, C P; Robertson, P

1993-02-26

CGP 43371 (compound I), a mono-pivaloyl oxazole derivative of a 3-piperazino-rifamycin, has been in clinical trials as a potential hypocholesterolemic agent. A reversed-phase high-performance liquid chromatographic (HPLC) assay was developed using a C18 column and a gradient solvent system of methanol-0.1 M sodium acetate, pH 4.5, at a flow-rate of 1 ml/min. The compound and internal standard (rifampicin) were detected by their ultraviolet absorption at 254 nm. Isolation of the compounds from plasma and liver homogenates was accomplished by precipitation of proteins with acetonitrile, followed by evaporation under nitrogen and reconstitution in methanol. Bile, lymph and urine were injected onto the HPLC column without pretreatment. Calibration curves were linear (r > 0.999) over the concentration range 0.25-20.0 micrograms/ml. The assay procedure was also applicable to other rifamycin derivatives and was able to distinguish between molecular species containing small differences in functionality.

Gas-liquid chromatographic determination of aniline metabolites of substituted urea and carbamate herbicides in aqueous solution.

Science.gov (United States)

Hargesheimer, E E; Coutts, R T; Pasutto, F M

1981-07-01

A simple gas-liquid chromatographic (GLC) method has been developed which provides sensitivity and specificity for the analysis of complex mixtures of the commonly occurring herbicide metabolites aniline, 3-chloroaniline, 4-chloroaniline, 4-bromoaniline, and 3-chloro-4-methylaniline. All of these anilines react with acetic anhydride directly in basified aqueous solution. Further reaction of the acetylated anilines with trifluoroacetic anhydride gave diacyl derivatives which were readily resolved by gas chromatography. The structures of the N-acetylated and N-trifluoroacetylated derivatives of benzylamine (internal standard) and the anilines were confirmed by GLC-mass spectrometry. In distilled water the minimum detectable concentrations of aniline and the substituted anilines, using electron capture GLC, are 0.1 nmole/100 mL and 0.05 nmole/100 mL, respectively. The detection limit for the anilines is 1 nmole/100 mL distilled water, using GLC with flame ionization detection. The technique was applied to the determination of anilines added to urine samples obtained from the general population.

Covalently coating dextran on macroporous polyglycidyl methacrylate microsphere enabled rapid protein chromatographic separation

Energy Technology Data Exchange (ETDEWEB)

Zhang, Rongyue; Li, Qiang; Li, Juan; Zhou, Weiqing; Ye, Peili; Gao, Yang; Ma, Guanghui, E-mail: ghma@home.ipe.ac.cn; Su, Zhiguo

2012-12-01

Protein denaturation and nonspecific adsorption on polymer media as a chromatographic support have been a problem which needs to be overcome. Macroporous poly(glycidyl methacrylate-divinylbezene) (PGMA-DVB) microspheres prepared in this study were firstly covalently coated with dextran through a three-step method. The dextran was firstly adsorbed onto the microspheres and then covalently bound to the PGMA-DVB microsphere through ether bonds which were formed by hydroxyl group reacting with epoxy group at the presence of 4-(Dimethylamino) pyridine. Finally, the coating dextran layer was crosslinked by ethylene glycol diglycidyl ether to form the continuous network coating. The coated microspheres were characterized by Fourier transform infrared spectra, scanning electron microscope, mercury porosimetry measurements, laser scanning confocal microscope, and protein adsorption experiments. Results showed that PGMA-DVB microspheres coated with dextran successfully maintained the macroporous structure and high permeability. The backpressure was only 1.69 MPa at a high flow rate of 2891 cm/h. Consequently, the hydrophilicity and biocompatibility of modified microspheres were greatly improved, and the contact angle decreased from 184 Degree-Sign to 13 Degree-Sign , and nonspecific adsorption of proteins was decreased to little or none. The clad dextran coating with large amounts of hydroxyl group was easily derived to be various functional groups. The derived media have great potential applications in rapid protein chromatography. - Highlights: Black-Right-Pointing-Pointer Macroporous PGMA-DVB microspheres were covalently coated with dextran. Black-Right-Pointing-Pointer The hydrophilicity of the coated microspheres was significantly improved. Black-Right-Pointing-Pointer The irreversible adsorption of proteins was reduced to zero. Black-Right-Pointing-Pointer The coated microspheres can maintain the macropore structure. Black-Right-Pointing-Pointer The coated microspheres

A high performance liquid chromatographic assay of Mefloquine in saliva after a single oral dose in healthy adult Africans

Directory of Open Access Journals (Sweden)

Gbotosho Grace O

2012-02-01

Full Text Available Abstract Background Mefloquine-artesunate is a formulation of artemisinin based combination therapy (ACT recommended by the World Health Organization and historically the first ACT used clinically. The use of ACT demands constant monitoring of therapeutic efficacies and drug levels, in order to ensure that optimum drug exposure is achieved and detect reduced susceptibility to these drugs. Quantification of anti-malarial drugs in biological fluids other than blood would provide a more readily applicable method of therapeutic drug monitoring in developing endemic countries. Efforts in this study were devoted to the development of a simple, field applicable, non-invasive method for assay of mefloquine in saliva. Methods A high performance liquid chromatographic method with UV detection at 220 nm for assaying mefloquine in saliva was developed and validated by comparing mefloquine concentrations in saliva and plasma samples from four healthy volunteers who received single oral dose of mefloquine. Verapamil was used as internal standard. Chromatographic separation was achieved using a Hypersil ODS column. Results Extraction recoveries of mefloquine in plasma or saliva were 76-86% or 83-93% respectively. Limit of quantification of mefloquine was 20 ng/ml. Agreement between salivary and plasma mefloquine concentrations was satisfactory (r = 0.88, p Conclusion Disposition of mefloquine in saliva paralleled that in plasma, making salivary quantification of mefloquine potentially useful in therapeutic drug monitoring.

Chromatographic determination of Terbinafine in presence of its Photodegradation products

International Nuclear Information System (INIS)

Abdel-Moety, E.M.; Kelani, K.O.; Abou Al-Alamein, A.M.

2003-01-01

Two different chromatographic techniques have been developed for the determination of terbinafine hydrochloride in presence of its photodegradation products. The first method depends on coupling the TLC- fractionation, on silicia gel 60F254 utilizing chloroform+methanol+25% aq. ammonia ( 12: 0.1:0.1,by volumes), with the direct scanning at 284nm. The second method describes a liquid chromatographic separation of terbinafine and its photolytic degradates on a reversed-phase column[u-Bondapak-TMC 18 (10um,25cmx4.6mm,i.d.)] using a mobile phase containing methanol+water= 80:20 (v/v) with UV-detection at 284 nm. The proposed methods showed significant stability-indication with good linearity, precision and reproducibility. (author)

Validation of a liquid chromatographic method for the pharmaceutical quality control of products containing elacridar

Directory of Open Access Journals (Sweden)

Emilia Sawicki

2016-08-01

Full Text Available Many anticancer drugs have an impaired bioavailability and poor brain penetration because they are substrates to drug efflux pumps such as P-glycoprotein and Breast Cancer Resistance Protein. Elacridar is a strong inhibitor of these two drug efflux pumps and therefore has great potential to improve oral absorption and brain penetration of many anticancer drugs. Currently, a clinical formulation of elacridar is unavailable and therefore the pharmaceutical development of a drug product is highly warranted. This also necessitates the availability of an analytical method for its quality control. A reverse-phase high-performance liquid chromatographic method with ultraviolet detection was developed for the pharmaceutical quality control of products containing elacridar as the active pharmaceutical ingredient. The analytical method was validated for linearity, accuracy, precision, selectivity, carry-over, stability of stock and reference solutions, stability of the final extract, stability-indicating capability and impurity testing. We found that elacridar is unstable in aqueous solutions that are exposed to light because a hydroxylation product of elacridar is formed. Therefore, sample solutions with elacridar must be protected from light.

Preparation of milk samples for immunoassay and liquid chromatographic screening using matrix solid-phase dispersion.

Science.gov (United States)

Barker, S A; Long, A R

1994-01-01

The use of drugs to maintain the health and maximize the output of dairy cattle has made the monitoring of milk for such agents essential. Screening tests based on immunological, microbial inhibition, and bacterial receptor assays have been developed for the detection of violative levels of therapeutic substances. However, such assays are not infallible, and false positive or negative results can occur when contaminants bind receptors or compete for the binding of the target residues. Such effects may arise from dietary sources, diseases, or other variables. Thus, a violation by such a test is not definitive until further confirmation is obtained. Our laboratory has developed extraction procedures for several drugs used in dairy production. Our method uses matrix solid-phase dispersion (MSPD) to isolate drugs away from contaminants and to eliminate many possible interferences. MSPD can also be used to enhance the specificity of such assays by fractionating various classes of drugs that may cross-react. Similarly, such methods may be used for liquid chromatographic screening and confirmation of a suspect sample.

Micellar Liquid Chromatographic Determination of Carbaryl and 1-Naphthol in Water, Soil, and Vegetables

Directory of Open Access Journals (Sweden)

Mei-Liang Chin-Chen

2012-01-01

Full Text Available A liquid chromatographic procedure has been developed for the determination of carbaryl, a phenyl-N-methylcarbamate, and its main metabolite 1-naphthol, using a C18 column (250’mm’ × ’4.6’mm with a micellar mobile phase and fluorescence detection at maximum excitation/emission wavelengths of 225/333’nm, respectively. In the optimization step, surfactants sodium dodecyl sulphate (SDS, Brij-35 and N-cetylpyridinium chloride monohydrate, and organic solvents propanol, butanol, and pentanol were considered. The selected mobile phase was 0.15’M SDS-6% (v/v-pentanol-0.01’M NaH2PO4 buffered at pH 3. Validation studies, according to the ICH Tripartite Guideline, included linearity (r>0.999, limit of detection (5 and 18’ng mL-1, for carbaryl and 1-naphthol, resp., and limit of quantification (15 and 50’ng mL-1, for carbaryl and 1-naphthol, resp., with intra- and interday precisions below 1%, and robustness parameters below 3%. The results show that the procedure was adequate for the routine analysis of these two compounds in water, soil, and vegetables samples.

[Influences of ion-suppressors on retention behaviors of nine food additives in reversed-phase high performance liquid chromatographic separation].

Science.gov (United States)

Zhao, Yonggang; Chen, Xiaohong; Li, Xiaoping; Yao, Shanshan; Jin, Micong

2011-10-01

The influences of ion-suppressors on retention behaviors of nine food additives, i.e., acesulfame, saccharin, caffeine, aspartame, benzoic acid, sorbic acid, stevioside, dehydroacetic acid and neotame in reversed-phase high performance liquid chromatographic (RP-HPLC) separation were investigated. The organic modification effects of acids, i. e. , trifluoroacetic acid (TFA) and buffer salts, i. e. , TFA-ammonium acetate (AmAc) were studied emphatically. The relationships between retention factors of solutes and volume percentages of ion-suppressors in the mobile phase systems of acetonitrile-TFA aqueous solution and acetonitrile-TFA-AmAc aqueous solution were quantitatively established, separately. The separation of nine food additives was completed by a gradient elution with acetonitrile-TFA (0.01%, v/v)-AmAc (2. 5 mmol/L) aqueous solution as the mobile phases. An RP-HPLC method was established for the simultaneous determination of nine food additives in red wine. In the range of 10. 0 - 100. 0 mg/L, nine food additives showed good linearity with the correlation coefficients ( r2 ) larger than 0. 999 1. The limits of detection (LODs) were in the range of 0. 33 - 2. 36 mg/L and the limits of quantification (LOQs) were in the range of 1. 11 - 7. 80 mg/L. The spiked recoveries were between 87. 61% and 108. 4% with the relative standard deviations (RSDs) of 2. 2% -9. 4%. These results are of referential significance for the rapid establishment and accu- rate optimization of RP-HPLC separation for the simultaneous determination of food additives in other foods.

Comparison of chromatographic methods for the determination of bound glycerol in biodiesel

Energy Technology Data Exchange (ETDEWEB)

Foglia, T.A.; Jones, K.C.; Nunez, A.; Phillips, J.G. [U.S. Dept. of Agriculture, Agricultural Research Service, Eastern Regional Research Center, Wyndmoor, PA (United States); Mittelbach, M. [Inst. for Chemistry, Univ. of Graz, Graz (Austria)

2004-09-01

An important fuel criterion for biodiesel is bound glycerol, which is a function of the residual amount of triglycerides and partial glycerides in the biodiesel. Either high-temperature gas chromatography or high performance liquid chromatography can be used for determining these minor but important components in biodiesel. In this paper we have conducted a statistical study on the accuracy of the two methods for ascertaining the bound glycerol in biodiesel fuels obtained from different feedstocks. Analysis of variance showed that with one exception, namely diacylglycerols in some soy oil based biodiesel, there was no statistical difference in bound glycerol for the biodiesel samples analyzed or a difference between methods. Operationally, the high performance liquid chromatographic method is superior to the high temperature gas chromatographic method in that it requires no sample derivatization, has shorter analysis times, and is directly applicable to most biodiesel fuels. (orig.)

Rapid determination of benzene derivatives in water samples by trace volume solvent DLLME prior to GC-FID

Energy Technology Data Exchange (ETDEWEB)

Diao, Chun Peng; Wei, Chao Hai; Feng, Chun Hua [South China Univ. of Technology, Guangzhou Higher Education Mega Center (China). College of Environmental Science and Engineering; Guangdong Regular Higher Education Institutions, Guangzhou (China). Key Lab. of Environmental Protection and Eco-Remediation

2012-05-15

An inexpensive, simple and environmentally friendly method based on dispersive liquid liquid microextraction (DLLME) for rapid determination of benzene derivatives in water samples was proposed. A significant improvement of DLLME procedure was achieved. Trace volume ethyl acetate (60 {mu}L) was exploited as dispersion solvent instead of common ones such as methanol and acetone, the volume of which was more than 0.5 mL, and the organic solvent required in DLLME was reduced to a great extent. Only 83-{mu}L organic solvent was consumed in the whole analytic process and the preconcentration procedure was less than 10 min. The advantageous approach coupled with gas chromatograph-flame ionization detector was proposed for the rapid determination of benzene, toluene, ethylbenzene and xylene isomers in water samples. Results showed that the proposed approach was an efficient method for rapid determination of benzene derivatives in aqueous samples. (orig.)

Isotope separations using chromatographic methods

International Nuclear Information System (INIS)

Leseticky, L.

1985-01-01

A survey is given of chromatographic separations of compounds only differing in isotope composition. Isotope effects on physical properties which allow chromatographic separation (vapour tension, adsorption heat, partition coefficient) are very small, with the exception of the simplest molecules. Therefore, separation factors only assume the value of several per cent. From this ensues the necessity of using columns which are specially and very carefully prepared and have a separation efficiency of the order of 10 4 theoretical plates. Briefly discussed is liquid chromatography on ion exchangers which with a varied degree of success was used for separating simple inorganic compounds or ions. Ion exchange chromatography of amino acids labelled with tritium, and chromatography of tritium labelled steroids also provided only a certain degree of separation. A detailed analysis is presented of gas chromatography separation of various deuterium and tritium labelled low-molecular compounds, to which a number of studies has been devoted in the literature. Very promising is the method of complexation gas chromatography based on the reversible formation of a complex of the ligand (the compound being separated) and the compound of the (transition) metal as the steady-state phase. (author)

Use of laminar chromatographic methods for determination of separation conditions in column extraction chromatography

International Nuclear Information System (INIS)

Ghersini, G.; Cerrai, E.

1978-01-01

Possibilities of using laminar chromatographic methods (paper and thin-layer chromatography) to determine optimal separation conditions in column extraction chromatography are analysed. Most of the given laminar methods are presented as Rf-spectra, i.e. as dependences of Rf found experimentally on eluating solution component concentration. Interrelation between Rf and distribution coefficients of corresponding liquid extraction systems and retention volumes of chromatographic columns is considered. Literature data on extraction paper and thin-layer chromatography of elements with various immovable phases are presented

Evaluation of rapid immuno chromatographic assay kit using monoclonal mpt64 antibodies for identification of mycobacterium tuberculosis complex

International Nuclear Information System (INIS)

Satti, L.; Ikram, A.; Malik, N.

2010-01-01

To evaluate the performance of rapid immuno chromatographic kit MPT64 Ag for the identification of Mycobacterium tuberculosis complex from various Mycobacterium tuberculosis culture positive specimens. Department of Microbiology, Armed Forces Institute of Pathology Rawalpindi, from August 2008 through March 2009. Eighty four Mycobacterium tuberculosis positive cultures on I BACTEC 460 and MGIT 960, one ATCC 25177 MTB strain, three institutional control MTB strains, two institutional control MOTT strains and 20 different bacterial isolates were tested. Tests were performed according to the instructional manual. Out of total 84 tested samples, MPT64 showed positive result in 80 cultures. Only four positive cultures did not display any band on MPT64 kit. These four strains were reconfirmed as Mycobacterium tuberculosis by PCR method. MOTT control strains and all the 20 bacterial isolates were negative for band. The sensitivity and specificity of ICT assay in our study was 95.2% and 100% respectively. Rapid MPT64 Kit is a good diagnostic tool to differentiate between Mycobacterium tuberculosis complex and MOTT with 100% specificity. The technique is simple and can provide prompt information to the clinicians to initiate early and appropriate antituberculosis therapy. (author)

Simple gas chromatographic method for furfural analysis.

Science.gov (United States)

Gaspar, Elvira M S M; Lopes, João F

2009-04-03

A new, simple, gas chromatographic method was developed for the direct analysis of 5-hydroxymethylfurfural (5-HMF), 2-furfural (2-F) and 5-methylfurfural (5-MF) in liquid and water soluble foods, using direct immersion SPME coupled to GC-FID and/or GC-TOF-MS. The fiber (DVB/CAR/PDMS) conditions were optimized: pH effect, temperature, adsorption and desorption times. The method is simple and accurate (RSDfurfurals will contribute to characterise and quantify their presence in the human diet.

Measurement Uncertainty of Liquid Chromatographic Analyses Visualized by Ishikawa Diagrams

OpenAIRE

Meyer, Veronika R.

2017-01-01

Ishikawa, or cause-and-effect diagrams, help to visualize the parameters that influence a chromatographic analysis. Therefore, they facilitate the set up of the uncertainty budget of the analysis, which can then be expressed in mathematical form. If the uncertainty is calculated as the Gaussian sum of all uncertainty parameters, it is necessary to quantitate them all, a task that is usually not practical. The other possible approach is to use the intermediate precision as a base for the uncer...

Rapid, facile synthesis of conjugated polymer zwitterions in ionic liquids

Energy Technology Data Exchange (ETDEWEB)

Page, Zachariah A. [Polymer Science & Engineering Department; Conte Center for Polymer Research; University of Massachusetts; Amherst, USA; Liu, Feng [Polymer Science & Engineering Department; Conte Center for Polymer Research; University of Massachusetts; Amherst, USA; Russell, Thomas P. [Polymer Science & Engineering Department; Conte Center for Polymer Research; University of Massachusetts; Amherst, USA; Emrick, Todd [Polymer Science & Engineering Department; Conte Center for Polymer Research; University of Massachusetts; Amherst, USA

2014-01-01

Ionic liquids (ILs) were utilized for the rapid air-stable Suzuki polymerization of polar zwitterionic thiophene monomers, precluding the need for volatile organic solvents, phosphine ligands and phase transfer catalysts typically used in conjugated polymer synthesis.

Artificial neural network model for photosynthetic pigments identification using multi wavelength chromatographic data

Science.gov (United States)

Prilianti, K. R.; Hariyanto, S.; Natali, F. D. D.; Indriatmoko, Adhiwibawa, M. A. S.; Limantara, L.; Brotosudarmo, T. H. P.

2016-04-01

The development of rapid and automatic pigment characterization method become an important issue due to the fact that there are only less than 1% of plant pigments in the earth have been explored. In this research, a mathematical model based on artificial intelligence approach was developed to simplify and accelerate pigment characterization process from HPLC (high-performance liquid chromatography) procedure. HPLC is a widely used technique to separate and identify pigments in a mixture. Input of the model is chromatographic data from HPLC device and output of the model is a list of pigments which is the spectrum pattern is discovered in it. This model provides two dimensional (retention time and wavelength) fingerprints for pigment characterization which is proven to be more accurate than one dimensional fingerprint (fixed wavelength). Moreover, by mimicking interconnection of the neuron in the nervous systems of the human brain, the model have learning ability that could be replacing expert judgement on evaluating spectrum pattern. In the preprocessing step, principal component analysis (PCA) was used to reduce the huge dimension of the chromatographic data. The aim of this step is to simplify the model and accelerate the identification process. Six photosynthetic pigments i.e. zeaxantin, pheophytin a, α-carotene, β-carotene, lycopene and lutein could be well identified by the model with accuracy up to 85.33% and processing time less than 1 second.

Development and validation of high-perfomance liquid chromatographic method for determination of ofloxacin and lomefloxacin in human plasma

Directory of Open Access Journals (Sweden)

DRAGICA ZENDELOVSKA

2005-12-01

Full Text Available Ahigh-performance liquid chromatographicmethod for the determination of ofloxacin and lomefloxacin in human plasma has been developed and validated. The effect of organic modifiers on the retention of the investigated drugs was investigated. Asimple isocratic chromatographic assay with UV-detection at 280 nm was performed on a Hibar Lichrospher 100 RP 8 column (250×4.6 mm, 5 mm. Merck, Germany using a mixture of acetonitrile and 0.5 % triethylamine in water (pH adjusted to 2.5 with H3PO4 (15:85, V/V as the mobile phase at flow rate of 1.2 mL min-1. The calibration curves were linear in the concentration ragne of 0.5 – 6.0 mg mL-1 for ofloxacin and 0.2-4.5 mg mL-1 for lomefloxacin.

Rapid determination of octanol-water partition coefficient using vortex-assisted liquid-liquid microextraction.

Science.gov (United States)

Román, Iván P; Mastromichali, Anna; Tyrovola, Konstantina; Canals, Antonio; Psillakis, Elefteria

2014-02-21

Vortex-assisted liquid-liquid microextraction (VALLME) coupled with high-performance liquid chromatography (HPLC) is proposed here for the rapid determination of octanol-water partitioning coefficients (Kow). VALLME uses vortex agitation, a mild emulsification procedure, to disperse microvolumes of octanol in the aqueous phase thus increasing the interfacial contact area and ensuring faster partitioning rates. With VALLME, 2min were enough to achieve equilibrium conditions between the octanolic and aqueous phases. Upon equilibration, separation was achieved using centrifugation and the octanolic microdrop was collected and analyzed in a HPLC system. Six model compounds with logKow values ranging between ∼0.5 and 3.5 were used during the present investigations. The proposed method produced logKow values that were consistent with previously published values and the recorded uncertainty was well within the acceptable log unit range. Overall, the key features of the proposed Kow determination procedure comprised speed, reliability, simplicity, low cost and minimal solvent consumption. Copyright © 2014 Elsevier B.V. All rights reserved.

High performance liquid chromatographic determination of ...

African Journals Online (AJOL)

STORAGESEVER

2010-02-08

) high performance liquid chromatography (HPLC) grade .... applications. These are important requirements if the reagent is to be applicable to on-line pre or post column derivatisation in a possible automation of the analytical.

Rapid quantification of imidazolium-based ionic liquids by hydrophilic interaction liquid chromatography: Methodology and an investigation of the retention mechanisms.

Science.gov (United States)

Hawkins, Cory A; Rud, Anna; Guthrie, Margaret L; Dietz, Mark L

2015-06-26

The separation of nine N,N'-dialkylimidazolium-based ionic liquids (ILs) by an isocratic hydrophilic interaction high-performance liquid chromatographic method using an unmodified silica column was investigated. The chosen analytical conditions using a 90:10 acetonitrile-ammonium formate buffer mobile phase on a high-purity, unmodified silica column were found to be efficient, robust, and sensitive for the determination of ILs in a variety of solutions. The retention window (k' = 2-11) was narrower than that of previous methods, resulting in a 7-min runtime for the nine IL homologues. The lower limit of quantification of the method, 2-3 μmol L(-1), was significantly lower than those reported previously for HPLC-UV methods. The effects of systematically modifying the IL cation alkyl chain length, column temperature, and mobile-phase water and buffer content on solute retention were examined. Cation exchange was identified as the dominant retention mechanism for most of the solutes, with a distinct (single methylene group) transition to a dominant partitioning mode at the highest solute polarity. Copyright © 2015 Elsevier B.V. All rights reserved.

Introducing a new and rapid microextraction approach based on magnetic ionic liquids: Stir bar dispersive liquid microextraction.

Science.gov (United States)

Chisvert, Alberto; Benedé, Juan L; Anderson, Jared L; Pierson, Stephen A; Salvador, Amparo

2017-08-29

With the aim of contributing to the development and improvement of microextraction techniques, a novel approach combining the principles and advantages of stir bar sorptive extraction (SBSE) and dispersive liquid-liquid microextraction (DLLME) is presented. This new approach, termed stir bar dispersive liquid microextraction (SBDLME), involves the addition of a magnetic ionic liquid (MIL) and a neodymium-core magnetic stir bar into the sample allowing the MIL coat the stir bar due to physical forces (i.e., magnetism). As long as the stirring rate is maintained at low speed, the MIL resists rotational (centrifugal) forces and remains on the stir bar surface in a manner closely resembling SBSE. By increasing the stirring rate, the rotational forces surpass the magnetic field and the MIL disperses into the sample solution in a similar manner to DLLME. After extraction, the stirring is stopped and the MIL returns to the stir bar without the requirement of an additional external magnetic field. The MIL-coated stir bar containing the preconcentrated analytes is thermally desorbed directly into a gas chromatographic system coupled to a mass spectrometric detector (TD-GC-MS). This novel approach opens new insights into the microextraction field, by using the benefits provided by SBSE and DLLME simultaneously, such as automated thermal desorption and high surface contact area, respectively, but most importantly, it enables the use of tailor-made solvents (i.e., MILs). To prove its utility, SBDLME has been used in the extraction of lipophilic organic UV filters from environmental water samples as model analytical application with excellent analytical features in terms of linearity, enrichment factors (67-791), limits of detection (low ng L -1 ), intra- and inter-day repeatability (RSD<15%) and relative recoveries (87-113%, 91-117% and 89-115% for river, sea and swimming pool water samples, respectively). Copyright © 2017 Elsevier B.V. All rights reserved.

Molecularly imprinted polymer cartridges coupled on-line with high performance liquid chromatography for simple and rapid analysis of dextromethorphan in human plasma samples.

Science.gov (United States)

Moein, Mohammad Mahdi; Javanbakht, Mehran; Akbari-Adergani, Behrouz

2011-04-01

In this paper, a novel method is described for automated determination of dextromethorphan in biological fluids using molecularly imprinted solid-phase extraction (MISPE) as a sample clean-up technique combined with high performance liquid chromatography (HPLC). The water-compatible molecularly imprinted polymers (MIPs) were prepared using methacrylic acid as functional monomer, ethylene glycol dimethacrylate as cross-linker, chloroform as porogen and dextromethorphan as template molecule. These imprinted polymers were used as solid-phase extraction sorbent for the extraction of dextromethorphan from human plasma samples. Various parameters affecting the extraction efficiency of the MIP cartridges were evaluated. The high selectivity of the sorbent coupled to the high performance liquid chromatographic system permitted a simple and rapid analysis of this drug in plasma samples with limits of detection (LOD) and quantification (LOQ) of 0.12 ng/mL and 0.35 ng/mL, respectively. The MIP selectivity was evaluated by analyzing of the dextromethorphan in presence of several substances with similar molecular structures and properties. Results from the HPLC analyses showed that the recoveries of dextromethorphan using MIP cartridges from human plasma samples in the range of 1-50 ng/mL were higher than 87%. Copyright © 2011 Elsevier B.V. All rights reserved.

Liquid chromatographic method for the simultaneous determination of cefalexin and trimethoprim in dog plasma and application to the pharmacokinetic studies of a coformulated preparation.

Science.gov (United States)

Qi, Meiling; Wang, Peng; Sun, Ping; Liu, Xia

2006-03-07

A liquid chromatographic method is described for the simultaneous determination of cefalexin and trimethoprim in dog plasma. A simple protein precipitation procedure was adopted for the sample preparation with satisfactory extraction recoveries for both analytes. Chromatographic separation of the analytes was achieved on a C(18) column using a mixture of 2 mol/l formate buffer (pH 3.5), methanol and acetonitrile (22:7:7, v/v/v) containing a 0.002 mol/l sodium dodecyl sulfate as mobile phase and detection was performed at 240 nm. The linearity was obtained over the concentration ranges of 1.0-100.0 microg/ml for cefalexin and 0.5-50.0 microg/ml for trimethoprim. For each level of QC samples including the lower limit of quantification, both inter- and intra-day precisions (R.S.D.) were trimethoprim, and accuracy (RE) was -1.4% for cefalexin and -3.0% for trimethoprim. The present LC method was successfully applied to the pharmacokinetic studies of coformulated cefalexin dispersible tablets after oral administration to beagle dogs.

Liquid chromatographic studies on the behaviour of Pu(III), Pu(IV) and Pu(VI) on a RP stationary phase in presence of α-hydroxyisobutyric acid as a chelating agent

Energy Technology Data Exchange (ETDEWEB)

Jaison, P.G.; Kumar, Pranaw; Telmore, Vijay M. [Bhabha Atomic Research Centre, Mumbai (India). Fuel Chemistry Division

2017-06-01

Since plutonium possesses multiple oxidation states which can coexist in solution, a method for the identification of these oxidation states is important to understand its chemical processes. Liquid chromatographic studies were carried out to compare the chromatographic behaviour of different oxidation states of Pu in presence of the eluent, α-hydroxyisobutyric acid (HIBA). The three oxidation states of Pu viz. Pu(III), Pu(IV) and Pu(VI) were separated under optimised conditions. It was seen that the presence of the complexing agent influences the equilibrium of Pu(III)/(IV) as well as Pu(IV)/(VI) systems. Pu(III) to Pu(IV) conversion was found to be enhanced by high pH and concentration of HIBA whereas a relatively low pH and high concentration of HIBA promotes the conversion of Pu(VI) to Pu(IV).

Derivatization reactions in the gas—liquid chromatographic analysis of drugs in biological fluids

NARCIS (Netherlands)

Hulshoff, A.; Lingeman, H.

1984-01-01

Alkylation, acylation, silylation and other derivatization reactions applied to the gas chromatographic analysis of drugs in biological matrices are reviewed. Reaction conditions are discussed in relation to reaction mechanisms. Detector-oriented labelling of drugs, and derivatization with chiral

High performance liquid chromatographic separation of thirteen drugs collected in Chinese Pharmacopoeia 2010(Ch.P2010 on cellulose ramification chiral stationary phase

Directory of Open Access Journals (Sweden)

Ying Zhou

2012-02-01

Full Text Available The enantiomers separation of thirteen drugs collected in Ch.P2010 was performed on chiral stationary phase of cellulose ramification (chiralpak OD and chiralpak OJ by high performance liquid chromatographic (HPLC methods, which included ibuprofen (C1, ketoprofen (C2, nitrendipine (C3, nimodipine (C4, felodipine (C5, omeprazole (C6, praziquantel (C7, propranolol hydrochloride (C8, atenolol (C9, sulpiride (C10, clenbuterol hydrochloride (C11, verapamil hydrochloride (C12, and chlorphenamine maleate (C13. The mobile phase consisted of isopropanol and n-hexane. The detection wavelength was set at 254 nm and the flow rate was 0.7 mL/min. The enantiomers separation of these thirteen racemates on chiralpak OD column and chiralpak OJ column was studied, while the effects of proportion of organic additives, alcohol displacer and temperature on the separation were studied. And the mechanism of some of racemates was discussed. The results indicated that thirteen chiral drugs could be separated on chiral stationary phase of cellulose ramification in normal phase chromatographic system. The chromatographic retention and resolution of enantiomers could be adjusted by factors including column temperature and the concentration of alcohol displacer and organic alkaline modifier in mobile phase. It was shown that the resolution was improved with reducing concentration of alcohol displacer. When concentration of organic alkaline modifier was 0.2% (v/v, the resolution and the peak shape were fairly good. Most racemates mentioned above had better resolution at column temperature of 25 °C. When racemates were separated, the temperature should be kept so as to obtain stable separation results. Keywords: HPLC, Chiral stationary phase, Optical enantiomers, Cellulose ramification

Radioimmunoassay and liquid-chromatographic analysis for free cortisol in urine compared with isotope dilution-mass spectrometry

International Nuclear Information System (INIS)

Lantto, O.

1982-01-01

Three different routine methods for analysis for urinary cortisol with those by a highly specific reference method based on isotope dilution-mass spectrometry (I) were compared. A ''high-performance'' liquid-chromatographic method (II) gave the most comparable results (regression coefficient 0.86, intercept 9 nmol/L). For some urines much lower values were obtained by I than by II. Two radioimmunoassay (III) methods, one involving direct assay and one involving extraction, gave less-accurate results (regression coefficients of 1.87 and 1.52 and intercepts of 86 and 12 nmol/L, respectively), although values obtained by III and by I correlated well (r = 0.95-0.99), indicating a relation between the free cortisol and the compounds interfering in III. The apparent accuracy for the extraction method was improved by using as calibration standards urine samples previously assayed by I (regression coefficient 0.90, intercept 6 nmol/L). All four methods investigated showed a statistically significant sex-related difference in 24-h urinary cortisol excretion; evidently such a finding should be a prerequisite in any such method proposed for routine use

Multivariate curve-resolution analysis of pesticides in water samples from liquid chromatographic-diode array data.

Science.gov (United States)

Maggio, Rubén M; Damiani, Patricia C; Olivieri, Alejandro C

2011-01-30

Liquid chromatographic-diode array detection data recorded for aqueous mixtures of 11 pesticides show the combined presence of strongly coeluting peaks, distortions in the time dimension between experimental runs, and the presence of potential interferents not modeled by the calibration phase in certain test samples. Due to the complexity of these phenomena, data were processed by a second-order multivariate algorithm based on multivariate curve resolution and alternating least-squares, which allows one to successfully model both the spectral and retention time behavior for all sample constituents. This led to the accurate quantitation of all analytes in a set of validation samples: aldicarb sulfoxide, oxamyl, aldicarb sulfone, methomyl, 3-hydroxy-carbofuran, aldicarb, propoxur, carbofuran, carbaryl, 1-naphthol and methiocarb. Limits of detection in the range 0.1-2 μg mL(-1) were obtained. Additionally, the second-order advantage for several analytes was achieved in samples containing several uncalibrated interferences. The limits of detection for all analytes were decreased by solid phase pre-concentration to values compatible to those officially recommended, i.e., in the order of 5 ng mL(-1). Copyright © 2010 Elsevier B.V. All rights reserved.

Liquid chromatographic determination of chloramine-T and its primary degradation product, p-toluenesulfonamide, in water

Science.gov (United States)

Dawson, Verdel K.; Davis, Ruth A.

1997-01-01

N-sodium-N-chloro-rho-toluenesulfonamide (chloramine-T) effectively controls bacterial gill disease (BGD) in cultured fishes, BGD, a common disease of hatchery-reared salmonids, causes more fish losses than any other disease among these species. This study describes a liquid chromatographic (LC) method that is capable of direct, simultaneous analysis of chloramine-T and its primary degradation product, rho-toluenesulfonamide (rho-TSA), in water. The procedure involves reversed-phase (C-18) LC analysis with ion suppression, using 0.01 M phosphate buffer at pH 3. The mobile phase is phosphate buffer-acetonitrile (60 + 40) at 1 mL/min. Both chemicals can be detected with a UV spectrophotometer at 229 nm; the method is linear up to 40 mg, chloramine-T or rho-TSA/L. Mean recoveries were 96.4 +/- 6.1% for water samples fortified with 0.03 mg chloramine-T/L and 95.3 +/- 4.6% for water samples fortified with 0.005 mg rho-TSA/L. Limits of detection without sample enrichment for chloramine-T and rho-TSA are 0.01 mg/L and 0.001 mg/L, respectively.

Systematic evaluation of commercially available ultra-high performance liquid chromatography columns for drug metabolite profiling: optimization of chromatographic peak capacity.

Science.gov (United States)

Dubbelman, Anne-Charlotte; Cuyckens, Filip; Dillen, Lieve; Gross, Gerhard; Hankemeier, Thomas; Vreeken, Rob J

2014-12-29

The present study investigated the practical use of modern ultra-high performance liquid chromatography (UHPLC) separation techniques for drug metabolite profiling, aiming to develop a widely applicable, high-throughput, easy-to-use chromatographic method, with a high chromatographic resolution to accommodate simultaneous qualitative and quantitative analysis of small-molecule drugs and metabolites in biological matrices. To this end, first the UHPLC system volume and variance were evaluated. Then, a mixture of 17 drugs and various metabolites (molecular mass of 151-749Da, logP of -1.04 to 6.7), was injected on six sub-2μm particle columns. Five newest generation core shell technology columns were compared and tested against one column packed with porous particles. Two aqueous (pH 2.7 and 6.8) and two organic mobile phases were evaluated, first with the same flow and temperature and subsequently at each column's individual limit of temperature and pressure. The results demonstrated that pre-column dead volume had negligible influence on the peak capacity and shape. In contrast, a decrease in post-column volume of 57% resulted in a substantial (47%) increase in median peak capacity and significantly improved peak shape. When the various combinations of stationary and mobile phases were used at the same flow rate (0.5mL/min) and temperature (45°C), limited differences were observed between the median peak capacities, with a maximum of 26%. At higher flow though (up to 0.9mL/min), a maximum difference of almost 40% in median peak capacity was found between columns. The finally selected combination of solid-core particle column and mobile phase composition was chosen for its selectivity, peak capacity, wide applicability and peak shape. The developed method was applied to rat hepatocyte samples incubated with the drug buspirone and demonstrated to provide a similar chromatographic resolution, but a 6 times higher signal-to-noise ratio than a more traditional UHPLC

Ionic Liquid-Liquid Chromatography: A New General Purpose Separation Methodology.

Science.gov (United States)

Brown, Leslie; Earle, Martyn J; Gîlea, Manuela A; Plechkova, Natalia V; Seddon, Kenneth R

2017-08-10

Ionic liquids can form biphasic solvent systems with many organic solvents and water, and these solvent systems can be used in liquid-liquid separations and countercurrent chromatography. The wide range of ionic liquids that can by synthesised, with specifically tailored properties, represents a new philosophy for the separation of organic, inorganic and bio-based materials. A customised countercurrent chromatograph has been designed and constructed specifically to allow the more viscous character of ionic liquid-based solvent systems to be used in a wide variety of separations (including transition metal salts, arenes, alkenes, alkanes, bio-oils and sugars).

High Performance Liquid Chromatographic Method for the Determination of Piroxicam, Naproxen, Diclofenac Sodium, and Mefenamic Acid in Bulk Drug and Pharmaceutical Preparations

Directory of Open Access Journals (Sweden)

Sarmad Bahjat Dikran

2018-03-01

Full Text Available A simple accurate and rapid reversed phase high performance liquid chromatographic method has been developed and validated for the determination of four nonsteroidal anti-inflammatory drugs;  Piroxicam(PX,  Naproxen(NAP,  Diclofenac sodium(DCL and Mefenamic acid(MFNC in their pure form and different commercial pharmaceutical formulation. The separation was performed on a NUCLEODUR® 100-5 C18ec (250 × 4.6 mm i.d.; particle size 5 μm column as stationary phase with a mobile phase comprising of acetonitrile: deionized water acidified with 1% acetic acid in gradient mode. The flow rate was 1.5 mL.min-1 at the temperature 35 ºC and detection was carried out at 264 nm. Separation has been completed within 8 min. The retention times of Piroxicam, Naproxen, Diclofenac sodium, and Mefenamic acid were 4.267 min, 4.785 min, 6.555 min, and 7.683 min respectively. The linearity for Piroxicam was in the range of 3–200 μg.mL-1 and for Naproxen and Mefenamic acid was in the range 1-200 μg.mL-1, while for Diclofenac sodium was in the range 1.5–200 μg.mL-1. The proposed method was successfully applied for the determination of these drugs in their pure form and different pharmaceutical preparations (tablets, capsules, and ampoule and there is no interference with additives.

Development and validation of a dissolution test with reversed-phase high performance liquid chromatographic analysis for Candesartan cilexetil in tablet dosage forms

Directory of Open Access Journals (Sweden)

Vairappan Kamalakkannan

2016-09-01

Full Text Available A simple, rapid, selective and reproducible reversed-phase high performance liquid chromatographic (RP-HPLC method has been developed and validated for the estimation of release of Candesartan cilexetil (CC in tablets. Analysis was performed on an Agilent, Zorbax C8 column (150mm × 4.6mm, 5μm with the mobile phase consisting of phosphate buffer (pH2.5–acetonitrile (15:85, v/v at a flow rate of 1.0mL/min. UV detection was performed at 215nm and the retention time for CC was 2.2. The calibration curve was linear (correlation coefficient = 1.000 in the selected range of analyte. The optimized dissolution conditions include the USP apparatus 2 at a paddle rotation rate of 50rpm and 900mL of phosphate buffer (pH7.2 with 0.03% of polysorbate 80 as dissolution medium, at 37.0 ± 0.5°C. The method was validated for precision, linearity, specificity, accuracy, limit of quantitation and ruggedness. The system suitability parameters, such as theoretical plate, tailing factor and relative standard deviation (RSD between six standard replicates were well within the limits. The stability result shows that the drug is stable in the prescribed dissolution medium. Three different batches (A, B and C of the formulation containing 8mg of Candesartan cilexetil was performed with the developed method and the results showed no significant differences among the batches.

Supercritical Fluid Chromatographic Separation of Dimethylpolysiloxane Polymer

Energy Technology Data Exchange (ETDEWEB)

Pyo, Dong Jin; Lim, Chang Hyun [Kangwon National University, Chuncheon (Korea, Republic of)

2005-02-15

Water was used as a polar modifier and a μ-porasil column as a saturator column. The μ-porasil column was inserted between the pump outlet and the injection valve. During the passage of the supercritical fluid mobile phase through the silica column, a polar modifier (water) can be dissolved in the pressurized supercritical fluid. Dimethylpolysiloxane polymer has been known as more polar polymer than polystyrene polymer. Dimethylpolysiloxane polymer has never been separated using water modified mobile phase. In this paper, using a μ-porasil column as a saturator column, excellent supercritical fluid chromatograms of dimethylpolysiloxane oligomers were obtained. The use of compressed (dense) gases and supercritical fluids as chromatographic mobile phases in conjunction with liquid chromatographic (LC)-type packed columns was first reported by Klesper et al. in 1962. During its relatively short history, supercritical fluid chromatography (SFC) has become an attractive alternative to GC and LC in certain industrially important applications. SFC gives the advantage of high efficiency and allows the analysis of nonvolatile or thermally labile mixtures.

Supercritical Fluid Chromatographic Separation of Dimethylpolysiloxane Polymer

International Nuclear Information System (INIS)

Pyo, Dong Jin; Lim, Chang Hyun

2005-01-01

Water was used as a polar modifier and a μ-porasil column as a saturator column. The μ-porasil column was inserted between the pump outlet and the injection valve. During the passage of the supercritical fluid mobile phase through the silica column, a polar modifier (water) can be dissolved in the pressurized supercritical fluid. Dimethylpolysiloxane polymer has been known as more polar polymer than polystyrene polymer. Dimethylpolysiloxane polymer has never been separated using water modified mobile phase. In this paper, using a μ-porasil column as a saturator column, excellent supercritical fluid chromatograms of dimethylpolysiloxane oligomers were obtained. The use of compressed (dense) gases and supercritical fluids as chromatographic mobile phases in conjunction with liquid chromatographic (LC)-type packed columns was first reported by Klesper et al. in 1962. During its relatively short history, supercritical fluid chromatography (SFC) has become an attractive alternative to GC and LC in certain industrially important applications. SFC gives the advantage of high efficiency and allows the analysis of nonvolatile or thermally labile mixtures

Fast and comprehensive analysis of secondary metabolites in cocoa products using ultra high-performance liquid chromatography directly after pressurized liquid extraction.

Science.gov (United States)

Damm, Irina; Enger, Eileen; Chrubasik-Hausmann, Sigrun; Schieber, Andreas; Zimmermann, Benno F

2016-08-01

Fast methods for the extraction and analysis of various secondary metabolites from cocoa products were developed and optimized regarding speed and separation efficiency. Extraction by pressurized liquid extraction is automated and the extracts are analyzed by rapid reversed-phase ultra high-performance liquid chromatography and normal-phase high-performance liquid chromatography methods. After extraction, no further sample treatment is required before chromatographic analysis. The analytes comprise monomeric and oligomeric flavanols, flavonols, methylxanthins, N-phenylpropenoyl amino acids, and phenolic acids. Polyphenols and N-phenylpropenoyl amino acids are separated in a single run of 33 min, procyanidins are analyzed by normal-phase high-performance liquid chromatography within 16 min, and methylxanthins require only 6 min total run time. A fourth method is suitable for phenolic acids, but only protocatechuic acid was found in relevant quantities. The optimized methods were validated and applied to 27 dark chocolates, one milk chocolate, two cocoa powders and two food supplements based on cocoa extract. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Vortex-assisted liquid-liquid microextraction for the rapid screening of short-chain chlorinated paraffins in water.

Science.gov (United States)

Chang, Chia-Yu; Chung, Wu-Hsun; Ding, Wang-Hsien

2016-01-01

The rapid screening of trace levels of short-chain chlorinated paraffins in various aqueous samples was performed by a simple and reliable procedure based on vortex-assisted liquid-liquid microextraction combined with gas chromatography and electron capture negative ionization mass spectrometry. The optimal vortex-assisted liquid-liquid microextraction conditions for 20 mL water sample were as follows: extractant 400 μL of dichloromethane; vortex extraction time of 1 min at 2500 × g; centrifugation of 3 min at 5000 × g; and no ionic strength adjustment. Under the optimum conditions, the limit of quantitation was 0.05 μg/L. Precision, as indicated by relative standard deviations, was less than 9% for both intra- and inter-day analysis. Accuracy, expressed as the mean extraction recovery, was above 91%. The vortex-assisted liquid-liquid microextraction with gas chromatography and electron capture negative ionization mass spectrometry method was successfully applied to quantitatively extract short-chain chlorinated paraffins from samples of river water and the effluent of a wastewater treatment plant, and the concentrations ranged from 0.8 to 1.6 μg/L. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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.

Coffee contains cholinomimetic compound distinct from caffeine. I: Purification and chromatographic analysis.

Science.gov (United States)

Tse, S Y

1991-07-01

Both regular and decaffeinated coffees were found to have cholinomimetic actions when tested in urethane-anesthetized rats. These actions were distinct from those of caffeine and reversible by atropine. The bioactive fraction was purified from alcoholic extracts of instant decaffeinated coffee by liquid column chromatography and preparative TLC. The purified compound showed similar pharmacological actions as the starting material. Chromatographic behavior was further characterized by analytical TLC and HPLC. Chromatographic analyses of extracts of green coffee beans and roasted ground coffees showed that the cardioactive compound was only present in roasted coffees. Similar analyses of other commonly consumed beverages, including teas and cocoa, showed that this compound was not present in beverages besides coffee.

Current applications of miniaturized chromatographic and electrophoretic techniques in drug analysis.

Science.gov (United States)

Aturki, Zeineb; Rocco, Anna; Rocchi, Silvia; Fanali, Salvatore

2014-12-01

In the last decade, miniaturized separation techniques have become greatly popular in pharmaceutical analysis. Miniaturized separation methods are increasingly utilized in all processes of drug discovery as well as quality control of pharmaceutical preparation. The great advantages presented by the analytical miniaturized techniques, including high separation efficiency and resolution, rapid analysis and minimal consumption of reagents and samples, make them an attractive alternative to the conventional chromatographic methods for drug analysis. The purpose of this review is to give a general overview of the applicability of capillary electrophoresis (CE), capillary electrochromatography (CEC) and micro/capillary/nano-liquid chromatography (micro-LC/CLC/nano-LC) for the analysis of pharmaceutical formulations, active pharmaceutical ingredients (API), drug impurity testing, chiral drug separation, determination of drugs and metabolites in biological fluids. The results concerning the use of CEC, micro-LC, CLC, and nano-LC in the period 2009-2013, while for CE, those from 2012 up to the review draft are here summarized and some specific examples are discussed. Copyright © 2014 Elsevier B.V. All rights reserved.

Incorporation of ionic liquid into porous polymer monoliths to enhance the separation of small molecules in reversed-phase high-performance liquid chromatography.

Science.gov (United States)

Wang, Jiafei; Bai, Ligai; Wei, Zhen; Qin, Junxiao; Ma, Yamin; Liu, Haiyan

2015-06-01

An ionic liquid was incorporated into the porous polymer monoliths to afford stationary phases with enhanced chromatographic performance for small molecules in reversed-phase high-performance liquid chromatography. The effect of the ionic liquid in the polymerization mixture on the performance of the monoliths was studied in detail. While monoliths without ionic liquid exhibited poor resolution and low efficiency, the addition of ionic liquid to the polymerization mixture provides highly increased resolution and high efficiency. The chromatographic performances of the monoliths were demonstrated by the separations of various small molecules including aromatic hydrocarbons, isomers, and homologues using a binary polar mobile phase. The present column efficiency reached 27 000 plates/m, which showed that the ionic liquid monoliths are alternative stationary phases in the separation of small molecules by high-performance liquid chromatography. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

[Development of an automatic vacuum liquid chromatographic device and its application in the separation of the components from Schisandra chinensis (Turz) Baill].

Science.gov (United States)

Zhu, Jingbo; Liu, Baoyue; Shan, Shibo; Ding, Yanl; Kou, Zinong; Xiao, Wei

2015-08-01

In order to meet the needs of efficient purification of products from natural resources, this paper developed an automatic vacuum liquid chromatographic device (AUTO-VLC) and applied it to the component separation of petroleum ether extracts of Schisandra chinensis (Turcz) Baill. The device was comprised of a solvent system, a 10-position distribution valve, a 3-position changes valve, dynamic axis compress chromatographic columns with three diameters, and a 10-position fraction valve. The programmable logic controller (PLC) S7- 200 was adopted to realize the automatic control and monitoring of the mobile phase changing, column selection, separation time setting and fraction collection. The separation results showed that six fractions (S1-S6) of different chemical components from 100 g Schisandra chinensis (Turcz) Baill. petroleum ether phase were obtained by the AUTO-VLC with 150 mm diameter dynamic axis compress chromatographic column. A new method used for the VLC separation parameters screened by using multiple development TLC was developed and confirmed. The initial mobile phase of AUTO-VLC was selected by taking Rf of all the target compounds ranging from 0 to 0.45 for fist development on the TLC; gradient elution ratio was selected according to k value (the slope of the linear function of Rf value and development times on the TLC) and the resolution of target compounds; elution times (n) were calculated by the formula n ≈ ΔRf/k. A total of four compounds with the purity more than 85% and 13 other components were separated from S5 under the selected conditions for only 17 h. Therefore, the development of the automatic VLC and its method are significant to the automatic and systematic separation of traditional Chinese medicines.

Chromatographic separation of radioactive noble gases from xenon

Science.gov (United States)

Akerib, D. S.; Araújo, H. M.; Bai, X.; Bailey, A. J.; Balajthy, J.; Beltrame, P.; Bernard, E. P.; Bernstein, A.; Biesiadzinski, T. P.; Boulton, E. M.; Bramante, R.; Cahn, S. B.; Carmona-Benitez, M. C.; Chan, C.; Chiller, A. A.; Chiller, C.; Coffey, T.; Currie, A.; Cutter, J. E.; Davison, T. J. R.; Dobi, A.; Dobson, J. E. Y.; Druszkiewicz, E.; Edwards, B. N.; Faham, C. H.; Fiorucci, S.; Gaitskell, R. J.; Gehman, V. M.; Ghag, C.; Gibson, K. R.; Gilchriese, M. G. D.; Hall, C. R.; Hanhardt, M.; Haselschwardt, S. J.; Hertel, S. A.; Hogan, D. P.; Horn, M.; Huang, D. Q.; Ignarra, C. M.; Ihm, M.; Jacobsen, R. G.; Ji, W.; Kamdin, K.; Kazkaz, K.; Khaitan, D.; Knoche, R.; Larsen, N. A.; Lee, C.; Lenardo, B. G.; Lesko, K. T.; Lindote, A.; Lopes, M. I.; Manalaysay, A.; Mannino, R. L.; Marzioni, M. F.; McKinsey, D. N.; Mei, D.-M.; Mock, J.; Moongweluwan, M.; Morad, J. A.; Murphy, A. St. J.; Nehrkorn, C.; Nelson, H. N.; Neves, F.; O'Sullivan, K.; Oliver-Mallory, K. C.; Palladino, K. J.; Pease, E. K.; Pech, K.; Phelps, P.; Reichhart, L.; Rhyne, C.; Shaw, S.; Shutt, T. A.; Silva, C.; Solovov, V. N.; Sorensen, P.; Stephenson, S.; Sumner, T. J.; Szydagis, M.; Taylor, D. J.; Taylor, W.; Tennyson, B. P.; Terman, P. A.; Tiedt, D. R.; To, W. H.; Tripathi, M.; Tvrznikova, L.; Uvarov, S.; Verbus, J. R.; Webb, R. C.; White, J. T.; Whitis, T. J.; Witherell, M. S.; Wolfs, F. L. H.; Yazdani, K.; Young, S. K.; Zhang, C.

2018-01-01

The Large Underground Xenon (LUX) experiment operates at the Sanford Underground Research Facility to detect nuclear recoils from the hypothetical Weakly Interacting Massive Particles (WIMPs) on a liquid xenon target. Liquid xenon typically contains trace amounts of the noble radioactive isotopes 85Kr and 39Ar that are not removed by the in situ gas purification system. The decays of these isotopes at concentrations typical of research-grade xenon would be a dominant background for a WIMP search experiment. To remove these impurities from the liquid xenon, a chromatographic separation system based on adsorption on activated charcoal was built. 400 kg of xenon was processed, reducing the average concentration of krypton from 130 ppb to 3.5 ppt as measured by a cold-trap assisted mass spectroscopy system. A 50 kg batch spiked to 0.001 g/g of krypton was processed twice and reduced to an upper limit of 0.2 ppt.

Surface-bonded ionic liquid stationary phases in high-performance liquid chromatography--a review.

Science.gov (United States)

Pino, Verónica; Afonso, Ana M

2012-02-10

Ionic liquids (ILs) are a class of ionic, nonmolecular solvents which remain in liquid state at temperatures below 100°C. ILs possess a variety of properties including low to negligible vapor pressure, high thermal stability, miscibility with water or a variety of organic solvents, and variable viscosity. IL-modified silica as novel high-performance liquid chromatography (HPLC) stationary phases have attracted considerable attention for their differential behavior and low free-silanol activity. Indeed, around 21 surface-confined ionic liquids (SCIL) stationary phases have been developed in the last six years. Their chromatographic behavior has been studied, and, despite the presence of a positive charge on the stationary phase, they showed considerable promise for the separation of neutral solutes (not only basic analytes), when operated in reversed phase mode. This aspect points to the potential for truly multimodal stationary phases. This review attempts to summarize the state-of-the-art about SCIL phases including their preparation, chromatographic behavior, and analytical performance. Copyright © 2011 Elsevier B.V. All rights reserved.

Rapid determination of 226Ra in drinking water samples using dispersive liquid-liquid microextraction coupled with liquid scintillation counting

International Nuclear Information System (INIS)

Sadi, B.K.; Chunsheng Li; Kramer, G.H.; Johnson, C.L.; Queenie Ko; Lai, E.P.C.

2011-01-01

A new radioanalytical method was developed for rapid determination of 226 Ra in drinking water samples. The method is based on extraction and preconcentration of 226 Ra from a water sample to an organic solvent using a dispersive liquid-liquid microextraction (DLLME) technique followed by radiometric measurement using liquid scintillation counting. In DLLME for 226 Ra, a mixture of an organic extractant (toluene doped with dibenzo-21-crown-7 and 2-theonyltrifluoroacetone) and a disperser solvent (acetonitrile) is rapidly injected into the water sample resulting in the formation of an emulsion. Within the emulsion, 226 Ra reacts with dibenzo-21-crown-7 and 2-theonyltrifluoroacetone and partitions into the fine droplets of toluene. The water/toluene phases were separated by addition of acetonitrile as a de-emulsifier solvent. The toluene phase containing 226 Ra was then measured by liquid scintillation counting. Several parameters were studied to optimize the extraction efficiency of 226 Ra, including water immiscible organic solvent, disperser and de-emulsifier solvent type and their volume, chelating ligands for 226 Ra and their concentrations, inorganic salt additive and its concentration, and equilibrium pH. With the optimized DLLME conditions, the accuracy (expressed as relative bias, B r ) and method repeatability (expressed as relative precision, S B ) were determined by spiking 226 Ra at the maximum acceptable concentration level (0.5 Bq L -1 ) according to the Guidelines for Canadian Drinking Water Quality. Accuracy and repeatability were found to be less than -5% (B r ) and less than 6% (S B ), respectively, for both tap water and bottled natural spring water samples. The minimum detectable activity and sample turnaround time for determination of 226 Ra was 33 mBq L -1 and less than 3 h, respectively. The DLLME technique is selective for extraction of 226 Ra from its decay progenies. (author)

Peak distortion in the column liquid chromatographic determination of omeprazole dissolved in borax buffer.

Science.gov (United States)

Arvidsson, T; Collijn, E; Tivert, A M; Rosén, L

1991-11-22

Injection of a sample containing omeprazole dissolved in borax buffer (pH 9.2) into a reversed-phase liquid chromatographic system consisting of a mixture of acetonitrile and phosphate buffer (pH 7.6) as the mobile phase and a C18 surface-modified silica as the solid phase resulted under special conditions in split peaks of omeprazole. The degree of peak split and the retention time of omeprazole varied with the concentration of borax in the sample solution and the ionic strength of the mobile phase buffer as well as with the column used. Borax is eluted from the column in a broad zone starting from the void volume of the column. The retention is probably due to the presence of polyborate ions. The size of the zone varies with the concentration of borax in the sample injected. In the borax zone the pH is increased compared with the pH of the mobile phase, and when omeprazole (a weak acid) is co-eluting in the borax zone its retention is affected. In the front part and in the back part of the borax zone, pH gradients are formed, and these gradients can induce the peak splitting. When the dissolving medium is changed to a phosphate buffer or an ammonium buffer at pH 9 no peak distortion of omeprazole is observed.

Liquid chromatographic determination of oxytetracycline in edible fish fillets from six species of fish

Science.gov (United States)

Meinertz, J.R.; Stehly, G.R.; Gingerich, W.H.

1998-01-01

The approved use of oxytetracycline (OTC) in U.S. Aquaculture is limited to specific diseases in salmonids and channel catfish. OTC may also be effective in controlling diseases in other fish species important to public aquaculture, but before approved use of OTC can be augmented, an analytical method for determining OTC in fillet tissue from multiple species of fish will be required to support residue depletion studies. The objective of this study was to develop and validate a liquid chromatographic (LC) method that is accurate, precise, and sensitive for OTC in edible fillets from multiple species of fish. Homogenized fillet tissues from walleye, Atlantic salmon, striped bass, white sturgeon, rainbow trout, and channel catfish were fortified with OTC at nominal concentrations of 10, 20, 100, 1000, and 5000 ng/g. In tissues fortified with OTC at 100, 1000, and 5000 ng/g, mean recoveries ranged from 83 to 90%, and relative standard deviations (RSDs) ranged from 0.9 to 5.8%. In all other tissues, mean recoveries ranged from 59 to 98%, and RSDs ranged from 3.3 to 20%. Method quantitation limits ranged from 6 to 22 ng/g for the 6 species. The LC parameters produced easily integratable OTC peaks without coelution of endogenous compounds. The method is accurate, precise, and sensitive for OTC in fillet tissue from 6 species of fish from 5 phylogenetically diverse groups.

Introducing a new and rapid microextraction approach based on magnetic ionic liquids: Stir bar dispersive liquid microextraction

International Nuclear Information System (INIS)

Chisvert, Alberto; Benedé, Juan L.; Anderson, Jared L.; Pierson, Stephen A.; Salvador, Amparo

2017-01-01

With the aim of contributing to the development and improvement of microextraction techniques, a novel approach combining the principles and advantages of stir bar sorptive extraction (SBSE) and dispersive liquid-liquid microextraction (DLLME) is presented. This new approach, termed stir bar dispersive liquid microextraction (SBDLME), involves the addition of a magnetic ionic liquid (MIL) and a neodymium-core magnetic stir bar into the sample allowing the MIL coat the stir bar due to physical forces (i.e., magnetism). As long as the stirring rate is maintained at low speed, the MIL resists rotational (centrifugal) forces and remains on the stir bar surface in a manner closely resembling SBSE. By increasing the stirring rate, the rotational forces surpass the magnetic field and the MIL disperses into the sample solution in a similar manner to DLLME. After extraction, the stirring is stopped and the MIL returns to the stir bar without the requirement of an additional external magnetic field. The MIL-coated stir bar containing the preconcentrated analytes is thermally desorbed directly into a gas chromatographic system coupled to a mass spectrometric detector (TD-GC-MS). This novel approach opens new insights into the microextraction field, by using the benefits provided by SBSE and DLLME simultaneously, such as automated thermal desorption and high surface contact area, respectively, but most importantly, it enables the use of tailor-made solvents (i.e., MILs). To prove its utility, SBDLME has been used in the extraction of lipophilic organic UV filters from environmental water samples as model analytical application with excellent analytical features in terms of linearity, enrichment factors (67–791), limits of detection (low ng L −1 ), intra- and inter-day repeatability (RSD<15%) and relative recoveries (87–113%, 91–117% and 89–115% for river, sea and swimming pool water samples, respectively). - Highlights: • A new microextraction method combining the

Study of stationary phase stability from a column with chromatographic material for steady state treatment of an effluent and/or waste containing Th-232

International Nuclear Information System (INIS)

Felinto, Maria Claudia Franca da Cunha; Martinz, Daniel Ortiz

1999-01-01

This work relates the behavior of a new chromatographic material, AMBERCMPO I, that has been studied to remove actinide elements from the High Level Liquid Waste. It gives emphasis to the behavior of chromatographic materials to the extraction of Th 4+ and its performance after some operation cycle. (author)

Rapid determination of methanol in black liquors by full evaporation headspace gas chromatography.

Science.gov (United States)

Li, Hailong; Zhan, Huaiyu; Fu, Shiyu; Liu, Mengru; Chai, Xin-Sheng

2007-12-14

This paper reported a full evaporation headspace gas chromatographic (GC) technique for determination of methanol content in black liquors (pulping spent liquor). In this method, a very small volume (10-20 microL) of liquor sample is introduced into a headspace sample vial (20 mL) and heated up to a temperature of 105 degrees C. A near-complete mass transfer of methanol from the liquid phase to vapor phase (headspace), i.e., a full evaporation, can be achieved within 3 min. The methanol in the headspace of the vial is then measured by GC. The present method is simple, rapid and accurate.

Arsenic speciation in sulfidic waters: reconciling contradictory spectroscopic and chromatographic evidence.

Science.gov (United States)

Planer-Friedrich, Britta; Suess, Elke; Scheinost, Andreas C; Wallschläger, Dirk

2010-12-15

In recent years, analytical methods have been developed that have demonstrated that soluble arsenic-sulfur species constitute a major fraction of dissolved arsenic in sulfidic waters. However, an intense debate is going on about the exact chemical nature of these compounds, since X-ray absorption spectroscopy (XAS) data generated at higher (mmol/L) concentrations suggest the presence of (oxy)thioarsenites in such waters, while ion chromatographic (IC) and mass spectroscopic data at lower (μmol/L to nmol/L) concentrations indicate the presence of (oxy)thioarsenates. In this contribution, we connect and explain these two apparently different types of results. We show by XAS that thioarsenites are the primary reaction products of arsenite and sulfide in geochemical model experiments in the complete absence of oxygen. However, thioarsenites are extremely unstable toward oxidation, and convert rapidly into thioarsenates when exposed to atmospheric oxygen, e.g., while waiting for analysis on the chromatographic autosampler. This problem can only be eliminated when the entire chromatographic process is conducted inside a glovebox. We also show that thioarsenites are unstable toward sample dilution, which is commonly employed prior to chromatographic analysis when ultrasensitive detectors like ICP-MS are used. This instability has two main reasons: if pH changes during dilution, then equilibria between individual arsenic-sulfur species rearrange rapidly due to their different stability regions within the pH range, and if pH is kept constant during dilution, then this changes the ratio between OH(-) and SH(-) in solution, which in turn shifts the underlying speciation equilibria. This problem is avoided by analyzing samples undiluted. Our studies show that thioarsenites appear as thioarsenates in IC analyses if oxygen is not excluded completely, and as arsenite if samples are diluted in alkaline anoxic medium. This also points out that thioarsenites are necessary

A rapid gas chromatographic injection-port derivatization method for the tandem mass spectrometric determination of patulin and 5-hydroxymethylfurfural in fruit juices.

Science.gov (United States)

Marsol-Vall, Alexis; Balcells, Mercè; Eras, Jordi; Canela-Garayoa, Ramon

2016-07-01

A novel method consisting of injection-port derivatization coupled to gas chromatography-tandem mass spectrometry is described. The method allows the rapid assessment of 5-hydroxymethylfurfural (HMF) and patulin content in apple and pear derivatives. The chromatographic separation of the compounds was achieved in a short chromatographic run (12.2min) suitable for routine controls of these compounds in the fruit juice industry. The optimal conditions for the injection-port derivatization were at 270°C, 0.5min purge-off, and a 1:2 sample:derivatization reagent ratio (v/v). These conditions represent an important saving in terms of derivatization reagent consumption and sample preparation time. Quality parameters were assessed for the target compounds, giving LOD of 0.7 and 1.6μg/kg and LOQ of 2 and 5μg/kg for patulin and HMF, respectively. These values are below the maximum patulin concentration in food products intended for infants and young children. Repeatability (%RSD n=5) was below 12% for both compounds. In addition, the method linearity ranged between 25 and 1000μg/kg and between 5 and 192μg/kg for HMF and patulin, respectively. Finally, the method was applied to study HMF and patulin content in various fruit juice samples. Copyright © 2016 Elsevier B.V. All rights reserved.

Liquid chromatography and supercritical fluid chromatography as alternative techniques to gas chromatography for the rapid screening of anabolic agents in urine.

Science.gov (United States)

Desfontaine, Vincent; Nováková, Lucie; Ponzetto, Federico; Nicoli, Raul; Saugy, Martial; Veuthey, Jean-Luc; Guillarme, Davy

2016-06-17

This work describes the development of two methods involving supported liquid extraction (SLE) sample treatment followed by ultra-high performance liquid chromatography or ultra-high performance supercritical fluid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS and UHPSFC-MS/MS) for the screening of 43 anabolic agents in human urine. After evaluating different stationary phases, a polar-embedded C18 and a diol columns were selected for UHPLC-MS/MS and UHPSFC-MS/MS, respectively. Sample preparation, mobile phases and MS conditions were also finely tuned to achieve highest selectivity, chromatographic resolution and sensitivity. Then, the performance of these two methods was compared to the reference routine procedure for steroid analyses in anti-doping laboratories, which combines liquid-liquid extraction (LLE) followed by gas chromatography coupled to tandem mass spectrometry (GC-MS/MS). For this purpose, urine samples spiked with the compounds of interest at five different concentrations were analyzed using the three analytical platforms. The retention and selectivity of the three techniques were very different, ensuring a good complementarity. However, the two new methods displayed numerous advantages. The overall procedure was much faster thanks to high throughput SLE sample treatment using 48-well plates and faster chromatographic analysis. Moreover, the highest sensitivity was attained using UHPLC-MS/MS with 98% of the doping agents detected at the lowest concentration level (0.1ng/mL), against 76% for UHPSFC-MS/MS and only 14% for GC-MS/MS. Finally, the weakest matrix effects were obtained with UHPSFC-MS/MS with 76% of the analytes displaying relative matrix effect between -20 and 20%, while the GC-MS/MS reference method displayed very strong matrix effects (over 100%) for all of the anabolic agents. Copyright © 2016 Elsevier B.V. All rights reserved.

Determination of biologically active phenols and polyphenols in various objects by chromatographic techniques

International Nuclear Information System (INIS)

Kochetova, M V; Semenistaya, E N; Larionov, Oleg G; Revina, A A

2007-01-01

Chromatographic techniques for determination of biologically active phenols and polyphenols are considered. Various methods for sample preparation and detection are compared. The advantages of high performance liquid chromatography with spectrophotometric detection for determination of antioxidants are demonstrated. Data on determination of biologically active phenols and polyphenols published in the period from 1995 to 2005 are analysed.

The gas-chromatographic and gas-chromatographic-mass-spectrometric identification of halogen-containing organic compounds

Science.gov (United States)

Gidaspov, B. V.; Zenkevich, I. G.; Rodin, A. A.

1989-09-01

The problem of identifying halogen-containing organic compounds in their gas-chromatographic and gas-chromatographic-mass-spectrometric (GC-MS) determination in different materials has been examined. Particular attention has been paid not to the complete characterisation of methods for carrying out this analysis but to the most important problem of increasing the selectivity at the stages of sampling, separation, and interpretation of the gas-chromatographic and GC-MS information. The bibliography contains 292 references.

Sheath liquid interface for the coupling of normal-phase liquid chromatography with electrospray mass spectrometry and its application to the analysis of neoflavonoids.

Science.gov (United States)

Charles, Laurence; Laure, Frédéric; Raharivelomanana, Phila; Bianchini, Jean-Pierre

2005-01-01

A novel interface that allows normal-phase liquid chromatography to be coupled with electrospray ionization (ESI) is reported. A make-up solution of 60 mM ammonium acetate in methanol, infused at a 5 microl min(-1) flow-rate at the tip of the electrospray probe, provides a sheath liquid which is poorly miscible with the chromatographic effluent, but promotes efficient ionization of the targeted analytes. Protonated molecules generated in the ESI source were subjected to tandem mass spectrometric experiments in a triple-quadrupole mass spectrometer. The main fragmentation reactions were characterized for each analyte and specific mass spectral transitions were used to acquire chromatographic data in the multiple reaction monitoring detection mode. Results obtained during optimization of the sheath liquid composition and flow-rate suggest that the electrospray process was mainly under the control of the make-up solution, and that it forms an external charged layer around a neutral chromatographic mobile phase core. This sheath liquid interface was implemented for the analysis of some neoflavonoid compounds and its performance was evaluated. Limits of detection were established for calophillolide, inophyllum B, inophyllum P and inophyllum C at 100, 25, 15 and 100 ng ml(-1), respectively.

Chromatographic background drift correction coupled with parallel factor analysis to resolve coelution problems in three-dimensional chromatographic data: quantification of eleven antibiotics in tap water samples by high-performance liquid chromatography coupled with a diode array detector.

Science.gov (United States)

Yu, Yong-Jie; Wu, Hai-Long; Fu, Hai-Yan; Zhao, Juan; Li, Yuan-Na; Li, Shu-Fang; Kang, Chao; Yu, Ru-Qin

2013-08-09

Chromatographic background drift correction has been an important field of research in chromatographic analysis. In the present work, orthogonal spectral space projection for background drift correction of three-dimensional chromatographic data was described in detail and combined with parallel factor analysis (PARAFAC) to resolve overlapped chromatographic peaks and obtain the second-order advantage. This strategy was verified by simulated chromatographic data and afforded significant improvement in quantitative results. Finally, this strategy was successfully utilized to quantify eleven antibiotics in tap water samples. Compared with the traditional methodology of introducing excessive factors for the PARAFAC model to eliminate the effect of background drift, clear improvement in the quantitative performance of PARAFAC was observed after background drift correction by orthogonal spectral space projection. Copyright © 2013 Elsevier B.V. All rights reserved.

The chromatographic behavior of arsenic compounds on anion exchange columns with binary organic acids as mobile phases

Energy Technology Data Exchange (ETDEWEB)

Zheng, J.; Goessler, W.; Kosmus, W. [Graz Univ. (Austria). Inst. fuer Analytische Chemie

1998-03-01

Identification and quantification of arsenic compounds was performed with high-performance liquid chromatography (HPLC) and flame atomic absorption spectrometry (FAAS) as element-specific detector. Arsenous acid, methylarsonic acid, dimethylarsinic acid, arsenic acid, arsenobetaine, and arsenocholine were separated on two anion-exchange columns (Synchropak Q 300 and PRP-X 100) with different binary organic acids as mobile phases. The influence of chromatographic parameters, such as pH and the concentration of the mobile phase were investigated. An unusual chromatographic behavior of arsenous acid was observed when tartaric acid was used as mobile phase. (orig.)

Improved stochastic resonance algorithm for enhancement of signal-to-noise ratio of high-performance liquid chromatographic signal

International Nuclear Information System (INIS)

Xie Shaofei; Xiang Bingren; Deng Haishan; Xiang Suyun; Lu Jun

2007-01-01

Based on the theory of stochastic resonance, an improved stochastic resonance algorithm with a new criterion for optimizing system parameters to enhance signal-to-noise ratio (SNR) of HPLC/UV chromatographic signal for trace analysis was presented in this study. Compared with the conventional criterion in stochastic resonance, the proposed one can ensure satisfactory SNR as well as good peak shape of chromatographic peak in output signal. Application of the criterion to experimental weak signals of HPLC/UV was investigated and the results showed an excellent quantitative relationship between different concentrations and responses

Determination of Diffusion Coefficients and Activation Energy of Selected Organic Liquids using Reversed-Flow Gas Chromatographic Technique

International Nuclear Information System (INIS)

Khalisanni Khalid; Rashid Atta Khan; Sharifuddin Mohd Zain

2012-01-01

Evaporation of vaporize organic liquid has ecological consequences when the compounds are introduced into both freshwater and marine environments through industrial effluents, or introduced directly into the air from industrial unit processes such as bioreactors and cooling towers. In such cases, a rapid and simple method are needed to measure physicochemical properties of the organic liquids. The Reversed-Flow Gas Chromatography (RF-GC) sampling technique is an easy, fast and accurate procedure. It was used to measure the diffusion coefficients of vapors from liquid into a carrier gas and at the same time to determine the rate coefficients for the evaporation of the respective liquid. The mathematical expression describing the elution curves of the samples peaks was derived and used to calculate the respective parameters for the selected liquid pollutants selected such as methanol, ethanol, 1-propanol, 1-butanol, n-pentane, n-hexane, n-heptane and n-hexadecane, evaporating into the carrier gas of nitrogen. The values of diffusion coefficients found were compared with those calculated theoretically or reported in the literature. The values of evaporation rate were used to determine the activation energy of respective samples using Arrhenius equation. An interesting finding of this work is by using an alternative mathematical analysis based on equilibrium at the liquid-gas interphase, the comparison leads to profound agreement between theoretical values of diffusion coefficients and experimental evidence. (author)

Stability-indicating liquid chromatographic method for quantification of new anti-epileptic drug lacosamide in bulk and pharmaceutical formulation

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Chhalotiya Usmangani K.

2012-01-01

Full Text Available An isocratic stability indicating reversed-phase liquid chromatographic determination was developed for the quantitative determination of lacosamide in the pharmaceutical dosage form. A Hypersil C-18, 4.5μm column with mobile phase containing acetonitrile-water (20:80, v/v was used. The flow rate was 1.0 mL min-1 and effluents were monitored at 258 nm. The retention time of lacosamide was 8.9 min. The method was found to be linear in the concentration range of 5-100 μg/ml and the recovery was found to be in the range of 99.15 - 100.09 %. The limit of detection and limit of quantification were found to be 2 μg/ml and 5 μg/ml, respectively. Lacosamide stock solutions were subjected to acid and alkali hydrolysis, chemical oxidation and dry heat degradation. The drug was found to be stable to the dry heat and acidic condition attempted. The proposed method was validated and successfully applied to the estimation of lacosamide in tablet dosage forms.

Rapid determination of environmental plutonium in large water samples by means of manganese dioxide Co-precipitation and extraction chromatographic separation

International Nuclear Information System (INIS)

Sidhu, R.S.; Hoff, P.

1999-01-01

Plutonium activity determinations in environmental water samples are routinely performed in many laboratories. Due to the low plutonium concentrations and the complexity of the plutonium aqueous chemistry, these analysis involve cumbersome preconcentration and separation procedures and long measurement times. We describe a procedure where MnO 2 (s) is used as scavenger to preconcentrate Pu prior to separation by the transuranium specific extraction chromatographic resin TRU-Resin. The ability of MnO 4 - /MnO 2 (s) to destroy organic matter and oxidise plutonium is combined with the specific behaviour of the TRU-resin for transuranium elements. The method facilitates a rapid preconcentration and separation of plutonium. With the use of this procedure, the laboratory work on one sample can be performed in one day with minimum attention. The overall yields from a 200 litre fresh- or seawater sample to a measurable Pu source are between 70-85%. (orig.)

Ultra-performance liquid chromatographic determination of L-ergothioneine in commercially available classes of cow milk.

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Sotgia, Salvatore; Pisanu, Elisabetta; Cambedda, Debora; Pintus, Gianfranco; Carru, Ciriaco; Zinellu, Angelo

2014-09-01

A new efficient and sensitive precolumn hydrophilic interaction ultra-performance liquid chromatography (HILIC-UPLC) method was established for the quantitative determination of L-ergothioneine (ERT) in milk. After derivatization of ERT with 7-diethylamino-3-[4-(iodoacetamido)phenyl]-4-methylcoumarin, chromatographic separation was achieved in a fairly short time, less than 5 min, on a 100 × 2.1 mm Waters Cortecs UPLC HILIC 1.6-μm column, by using a mixture of 30 mmol/L ammonium acetate/acetonitrile (10:90, v/v) as a mobile phase flowing isocratically at 0.9 mL/min. Limit of detection and the limit of quantification were 0.03 and 0.10 μmol/L, respectively. The method exhibited linearity in a concentration range of 0.16 and 5.08 μmol/L. Mean recovery was 106.66%, whereas intra- and interassay precisions were determined to be within 6 RSD%. On average, ERT concentration in different commercially available classes of cow milk was found to be 0.442 ± 0.191 μmol/L, with the highest levels in the ultra-high temperature milks and low values in the unprocessed and HTST whole milks. In this light, our experiments suggest that ERT could be used as a marker for the heat treatment of milk. © 2014 Institute of Food Technologists®

Assessment of chromatographic methods for the chemical stability of a new miconazole nitrate cream

International Nuclear Information System (INIS)

Garcia Pulpeiro, Oscar; Calzadilla Aguiar, Wendy; Rodriguez Bencomo, Wendy

2013-01-01

To assess the chromatographic methods for the chemical stability of a new 2 % miconazol nitrate cream. arious degradation conditions were firstly used in the raw material miconazole nitrate in order to obtain the possible degradation products of this drug and to evaluate them by thin layer chromatography-based method, which was validated to identify the degradation products in the new cream. The performance of the official method based on high resolution liquid chromatography and reported in British Pharmacopoeia 2010 was evaluated, and its selectivity against the possible degradation products were also analyzed. Both chromatographic methods were applied to the analysis of cream samples from the three pilot batches under heat stress for 30 days

Optimization of chromatographic conditions for determination of aflatoxin B1, B2, G1 and G2 by using liquid chromatography-mass Spectrometry

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Ramadhaningtyas, Dillani Putri; Aryana, Nurhani; Aristiawan, Yosi; Styarini, Dyah

2017-11-01

The optimization of instrument condition and chromatographic separation for analysis of aflatoxin B1, B2, G1 and G2 using liquid chromatography tandem with mass spectrometer detector was conducted in the aim to provide more accurate and reliable analysis results. The aflatoxin known to be serious threat for human health as it is classified as the carcinogenic compounds. The aflatoxin B1, B2, G1 and G2 were selected due to its extensive contamination in various agricultural commodities. The best chromatographic separation was obtained using C-18 column with gradient elution of solvent 5 mM ammonium acetate and 0.1% formic acid in methanol at 7 minutes runtime analysis. The linearity of the detector showed satisfied results as the coefficient determination found to be 0.9994, 0.9996, 0.9998 and 0.9987 for aflatoxin B1, G1, B2, and G2 respectively in the range concentration from 1 to 20 ng/g. The quantifier ion selected for the aflatoxin B1, B2, G1 and G2 was m/z 285.1, 259, 243 and 313 respectively. The instrument precision at these quantifier ions also showed satisfied result with %RSD was around 3.4 to 6.8%. The optimized method present in this study can be used for further sample analysis.

Forensic Analysis of Blue Ball point Pen Inks Using Ultraviolet-Visible Spectrometer and Ultra-Performance Liquid Chromatograph

International Nuclear Information System (INIS)

Lee, L.C.; Shandu, K.T.S.; Nor Syahirah Mohamad Razi; Ab Aziz Ishak; Khairul Osman

2015-01-01

Twelve varieties of blue ball point pens were selected and analyzed using UV-Vis spectrometer and ultra-performance liquid chromatography (UPLC). The aim of the study was to determine discrimination power (DP) of these methods in differentiating pen inks collected from the market in Malaysia. Discrimination analysis of 66 possible pen-pair of blue ball point pens was carried out via one-way ANOVA based on obtained chromatogram and spectra. A total of 18 peaks were determined as coming from inks based on the chromatographic data extracted at three different wavelengths (279, 370 and 400 nm). While for the UV-Vis spectrometer analysis, presence of peaks at 303, 545, 577 and 584 nm wavelengths were recorded. UV-Vis spectral data were mainly produced by the colorant components (for example, dyes) found in inks and UPLC may detect ink components other than dyes, for example, additives. As conclusion, the DP for UV-Vis and UPLC were determined to be 72.12 % and 98.48 %, respectively. This manuscript demonstrates the potential of UPLC for discriminating pen inks based on non-dye components. Additionally, the dye components in inks do not seem to play important role in discrimination of pen inks. (author)

Liquid chromatographic determination of urinary 2-thiothiazolidine-4-carboxylic acid, a biomarker of carbon disulphide exposure.

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Lee, B L; Yang, X F; New, A L; Ong, C N

1995-06-23

An effective gradient high-performance liquid chromatographic method for baseline separation of urinary 2-thiothiazolidine-4-carboxylic acid (TTCA), with photodiode array detection at 271 nm was described. o-Methylhippuric acid was used as an internal standard (I.S.). A 1-ml urine sample was saturated with 300 mg of sodium sulphate, acidified with 100 microliters of 6 M hydrochloric acid, extracted twice with 2 ml of diethyl ether, and after evaporation, the residue was taken up in 1 ml of 0.1% (v/v) phosphoric acid. The two mobile phases used for gradient elution were: (A) 10 mM ammonium dihydrogenphosphate (pH 3.5) and (B) same concentration of buffer but containing 20% (v/v) of methanol (pH 4.8). The flow-rate was set at 1.0 ml/min. TTCA and I.S. were detected at 2.2 and 9.1 min, respectively. The method was validated with urine samples collected from normal subjects and workers occupationally exposed to carbon disulphide. The present method enables the detection of urinary TTCA at a concentration of 0.025 mg/l. Analytical recovery and reproducibility generally exceeded 90%. The proposed method is considered more sensitive, specific and reliable than other existing methods.

Recent development of ionic liquid stationary phases for liquid chromatography.

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Shi, Xianzhe; Qiao, Lizhen; Xu, Guowang

2015-11-13

Based on their particular physicochemical characteristics, ionic liquids have been widely applied in many fields of analytical chemistry. Many types of ionic liquids were immobilized on a support like silica or monolith as stationary phases for liquid chromatography. Moreover, different approaches were developed to bond covalently ionic liquids onto the supporting materials. The obtained ionic liquid stationary phases show multi-mode mechanism including hydrophobic, hydrophilic, hydrogen bond, anion exchange, π-π, and dipole-dipole interactions. Therefore, they could be used in different chromatographic modes including ion-exchange, RPLC, NPLC and HILIC to separate various classes of compounds. This review mainly summarizes the immobilized patterns and types of ionic liquid stationary phases, their retention mechanisms and applications in the recent five years. Copyright © 2015 Elsevier B.V. All rights reserved.

Liquid chromatography tandem mass spectrometry method for simultaneous determination of metoprolol tartrate and ramipril in human plasma.

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Gowda, K Veeran; Mandal, Uttam; Senthamil Selvan, P; Sam Solomon, W D; Ghosh, Animesh; Sarkar, Amlan Kanti; Agarwal, Sangita; Nageswar Rao, T; Pal, Tapan Kumar

2007-10-15

A simple, rapid, sensitive and specific liquid chromatography-tandem mass spectrometry method was developed and validated for quantification of metoprolol tartrate (MT) and ramipril, in human plasma. Both the drugs were extracted by liquid-liquid extraction with diethyl ether-dichloromethane (70:30, v/v). The chromatographic separation was performed on a reversed-phase C8 column with a mobile phase of 10 mM ammonium formate-methanol (3:97, v/v). The protonated analyte was quantitated in positive ionization by multiple reaction monitoring with a mass spectrometer. The method was validated over the concentration range of 5-500 ng/ml for metoprolol and ramipril in human plasma. The precursor to product ion transitions of m/z 268.0-103.10 and m/z 417.20-117.20 were used to measure metoprolol and ramipril, respectively.

Evaluation of highly polar ionic liquid gas chromatographic column for the determination of the fatty acids in milk fat.

Science.gov (United States)

Delmonte, Pierluigi; Fardin-Kia, Ali Reza; Kramer, John K G; Mossoba, Magdi M; Sidisky, Len; Tyburczy, Cynthia; Rader, Jeanne I

2012-04-13

The SLB-IL111, a new ionic liquid capillary column for gas chromatography available from Supelco Inc., was recently shown to provide enhanced separation of unsaturated geometric and positional isomers of fatty acid (FAs) when it was compared to cyanopropylsiloxane (CPS) columns currently recommended for the analysis of fatty acid methyl esters (FAMEs). A 200 m SLB-IL111 capillary column, operated under a combined temperature and eluent flow gradient, was successfully used to resolve most of the FAs contained in milk fat in a single 80 min chromatographic separation. The selected chromatographic conditions provided a balanced, simultaneous separation of short-chain (from 4:0), long-chain polyunsaturated fatty acids (PUFAs), and most of the unsaturated FA positional/geometric isomers contained in milk fat. Among the monounsaturated fatty acids (MUFAs), these conditions separated t11-18:1 and t10-18:1 FAs, the two most abundant trans fatty acids (t-FA) contained in most dairy products. These t-FAs reportedly have different biological activities. The conjugated linoleic acid (CLA) isomers commonly found in dairy products were separated from each other, including t7,c9-18:2 from c9,t11-18:2, which eliminated the need for their complementary silver ion HPLC analysis. The application of the SLB-IL111 column provided a complementary elution profile of FAMEs to those obtained by CPS columns, allowing for a more comprehensive FA analysis of total milk fat. The FAMEs were identified by the use of available reference materials, previously synthesized and characterized reference mixtures, and prior separations of the milk fat FAMEs by silver ion chromatography based on the number/geometry of double bonds. Published by Elsevier B.V.

Industrial scale chromatographic separation of valuable compounds from biomass hydrolysates and side streams

Energy Technology Data Exchange (ETDEWEB)

Saari, P.

2011-06-15

Carbohydrates are composed of a number of various monosaccharides, glucose being the most abundant. Some of the monosaccharides are valuable compounds used in the food and pharmaceutical industries. They can be separated from biomass hydrolysates e.g. by chromatographic methods. In this thesis, chromatographic separation of valuable compounds using ion exchange resins was studied on an industrial scale. Of special interest were rare monosaccharides in biomass hydrolysates. A novel chromatographic separation process was developed for fucose, starting from pre-processed spent sulfite liquor. The core of the process consists of three chromatographic separations with different types of ion exchange resins. Chromatographic separation of galactose was tested with three biomass hydrolysates; lactose, gum arabic and hemicellulose hydrolysates. It was demonstrated that also galactose can be separated from complex carbohydrate mixtures. A recovery process for arabinose from citrus pectin liquid residual and for mannose from wood pulp hydrolysate were also developed and experimentally verified. In addition to monosaccharides, chromatographic separation of glycinebetaine from vinasse was examined with a hydrogen form weak acid cation exchange resin. The separation involves untypical peak formation depending, for example, on the pH and the cation composition. The retention mechanism was found to be hydrogen bonding between glycinebetaine and the resin. In the experimental part, all four resin types - strong acid cation, strong base anion, weak acid cation and weak base anion exchange resins - were used. In addition, adsorption equilibria data of seven monosaccharides and sucrose were measured with the resins in sodium and sulfate forms because such data have been lacking. It was found out that the isotherms of all sugars were linear under industrial conditions. A systematic method for conceptual process design and sequencing of chromatographic separation steps were developed

Critical Evaluation of Acetylcholine Determination in Rat Brain Microdialysates using Ion-Pair Liquid Chromatography with Amperometric Detection

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Yvette Michotte

2008-08-01

Full Text Available Liquid chromatography with amperometric detection remains the most widely used method for acetylcholine quantification in microdialysis samples. Separation of acetylcholine from choline and other matrix components on a microbore chromatographic column (1 mm internal diameter, conversion of acetylcholine in an immobilized enzyme reactor and detection of the produced hydrogen peroxide on a horseradish peroxidase redox polymer coated glassy carbon electrode, achieves sufficient sensitivity for acetylcholine quantification in rat brain microdialysates. However, a thourough validation within the concentration range required for this application has not been carried out before. Furthermore, a rapid degradation of the chromatographic columns and enzyme systems have been reported. In the present study an ion-pair liquid chromatography assay with amperometric detection was validated and its long-term stability evaluated. Working at pH 6.5 dramatically increased chromatographic stability without a loss in sensitivity compared to higher pH values. The lower limit of quantification of the method was 0.3 nM. At this concentration the repeatability was 15.7%, the inter-day precision 8.7% and the accuracy 103.6%. The chromatographic column was stable over 4 months, the immobilized enzyme reactor up to 2-3 months and the enzyme coating of the amperometric detector up to 1-2 months. The concentration of acetylcholine in 30 μl microdialysates obtained under basal conditions from the hippocampus of freely moving rats was 0.40 ± 0.12 nM (mean ± SD, n = 30. The present method is therefore suitable for acetylcholine determination in rat brain microdialysates.

Experimental observations of flow instabilities and rapid mixing of two dissimilar viscoelastic liquids

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Hiong Yap Gan

2012-12-01

Full Text Available Viscoelastically induced flow instabilities, via a simple planar microchannel, were previously used to produce rapid mixing of two dissimilar polymeric liquids (i.e. at least a hundredfold different in shear viscosity even at a small Reynolds number. The unique advantage of this mixing technology is that viscoelastic liquids are readily found in chemical and biological samples like organic and polymeric liquids, blood and crowded proteins samples; their viscoelastic properties could be exploited. As such, an understanding of the underlying interactions will be important especially in rapid microfluidic mixing involving multiple-stream flow of complex (viscoelastic fluids in biological assays. Here, we use the same planar device to experimentally show that the elasticity ratio (i.e. the ratio of stored elastic energy to be relaxed between two liquids indeed plays a crucial role in the entire flow kinematics and the enhanced mixing. We demonstrate here that the polymer stretching dynamics generated in the upstream converging flow and the polymer relaxation events occurring in the downstream channel are not exclusively responsible for the transverse flow mixing, but the elasticity ratio is also equally important. The role of elasticity ratio for transverse flow instability and the associated enhanced mixing were illustrated based on experimental observations. A new parameter Deratio = Deside / Demain (i.e. the ratio of the Deborah number (De of the sidestream to the mainstream liquids is introduced to correlate the magnitude of energy discontinuity between the two liquids. A new Deratio-Demain operating space diagram was constructed to present the observation of the effects of both elasticity and energy discontinuity in a compact manner, and for a general classification of the states of flow development.

Recent advances in metal-organic frameworks and covalent organic frameworks for sample preparation and chromatographic analysis.

Science.gov (United States)

Wang, Xuan; Ye, Nengsheng

2017-12-01

In the field of analytical chemistry, sample preparation and chromatographic separation are two core procedures. The means by which to improve the sensitivity, selectivity and detection limit of a method have become a topic of great interest. Recently, porous organic frameworks, such as metal-organic frameworks (MOFs) and covalent organic frameworks (COFs), have been widely used in this research area because of their special features, and different methods have been developed. This review summarizes the applications of MOFs and COFs in sample preparation and chromatographic stationary phases. The MOF- or COF-based solid-phase extraction (SPE), solid-phase microextraction (SPME), gas chromatography (GC), high-performance liquid chromatography (HPLC) and capillary electrochromatography (CEC) methods are described. The excellent properties of MOFs and COFs have resulted in intense interest in exploring their performance and mechanisms for sample preparation and chromatographic separation. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Rapid differentiation of rocky mountain spotted fever from chickenpox, measles, and enterovirus infections and bacterial meningitis by frequency-pulsed electron capture gas-liquid chromatographic analysis of sera.

Science.gov (United States)

Brooks, J B; McDade, J E; Alley, C C

1981-01-01

Normal sera and sera from patients with Rocky Mountain spotted fever, chickenpox, enterovirus infections, measles, and Neisseria meningitidis infections were extracted with organic solvents under acidic and basic conditions and then derivatized with trichloroethanol or heptafluorobutyric anhydride-ethanol to form electron-capturing derivatives of organic acids, alcohols, and amines. The derivatives were analyzed by frequency-pulsed electron capture gas-liquid chromatography (FPEC-GLC). There were unique differences in the FPEC-GLC profiles of sera obtained from patients with these respective diseases. With Rocky Mountain spotted fever patients, typical profiles were detected as early as 1 day after onset of disease and before antibody could be detected in the serum. Rapid diagnosis of Rocky Mountain spotted fever by FPEC-GLC could permit early and effective therapy, thus preventing many deaths from this disease. PMID:7276147

Determination and validation of a simple high-performance liquid chromatographic method for simultaneous assay of iprodione and vinclozolin in human urine.

Science.gov (United States)

Carlucci, Giuseppe; Pasquale, Dorina Di; Ruggieri, Fabrizio; Mazzeo, Pietro

2005-12-15

A method based on solid-phase extraction (SPE) and high-performance liquid chromatography (HPLC) was developed for the simultaneous determination of 3-(3,5-diclorophenyl)-5-ethenyl-5-methyl-2,4-oxazolidinedione (vinclozolin) and 3-(3,5-diclorophenyl)-N-(1-methylethyl)-2,4-dioxo-1-imidazolidinecarboxamide (iprodione) in human urine. Urine samples containing vinclozolin and iprodione were collected by solid phase extraction using C(18) cartridges. The chromatographic separation was achieved on a Spherisorb ODS2 (250 mm x 4.6 mm, 5 microm) column with an isocratic mobile phase of acetonitrile-water (60:40, v/v). Detection was UV absorbance at 220 nm. The calibration graphs were linear from 30 to 1000 ng/mL for the two fungicides. Intra- and inter-day R.S.D. did not exceed 2.9%. The quantitation limit was 50 ng/mL for vinclozolin and 30 ng/mL for iprodione, respectively.

Chiral high-performance liquid chromatographic analysis of fluoxetine and norfluoxetine in rabbit plasma, urine, and vitreous humor using an acetylated beta-cyclodextrin column.

Science.gov (United States)

Yee, L; Wong, S H; Skrinska, V A

2000-10-01

Fluoxetine (Prozac) is a potent selective serotonin reuptake inhibitor used for the treatment of major depression. Both fluoxetine (F) and its demethylated metabolite, norfluoxetine (NF), are racemic. S-Fluoxetine (SF) and S-norfluoxetine (SNF) are more potent inhibitors of serotonin reuptake than R-fluoxetine (RF) and R-norfluoxetine (RNF). Quantitation of individual enantiomers may provide a greater understanding of pharmacokinetic properties. The objective of this study was to perform a limited chiral selectivity study using rabbit plasma, urine, and vitreous humor analyzed by a solid-phase extraction protocol and a newly developed chiral analysis with an acetylated beta-cyclodextrin (CD) column. Liquid chromatographic parameters for CD were as follows: a mobile phase composition of methanol/0.3% triethylamine buffer, pH 5.6, (30:70), a flow rate of 1 mL/min, detection at 214 nm, and a temperature of 40 degrees C. Elution order was SNF, SF, RNF, and RF with capacity factors of 6, 7, 8, and 9, respectively. The corresponding resolution factors were as follows: R1,2 = 0.8, R2,3 = 1.2, and R3,4 = 0.9. The conditions for solid-phase extraction were optimized for Varian Bond Elut Certify columns. Following sample application, the column was rinsed with water, acetic acid, and then with methanol. Drug enantiomers were eluted with methylene chloride, isopropanol, and ammonium hydroxide (78:20:2). After extract evaporation, the extract residue was reconstituted for high-performance liquid chromatographic analysis. To investigate chiral pharmacology, a biodistribution study was performed by administering 2 mg/kg of F to five rabbits. Blood, urine, and vitreous specimens were collected. Plasma samples collected 45 min postinjection showed nearly equal concentrations of RF and SE After 24 h, the only metabolite detected in plasma was RNF. Drugs were not detectable in vitreous humor. Urine concentrations of SNF, SF, RNF, and RF were 51, 76, 34, and 8 microg/L, respectively

Liquid chromatographic determination of CPZEN-45, a novel anti-tubercular drug, in biological samples.

Science.gov (United States)

Hanif, S N M; Hickey, A J; Garcia-Contreras, L

2014-01-01

CPZEN-45 is a new drug candidate being considered for the treatment of tuberculosis (TB). The aim of this study was to develop and validate a reverse-phase high-performance liquid chromatographic (HPLC) method suitable to determine CPZEN-45 concentrations in biological samples. CPZEN-45 was extracted from biological fluids and tissues (plasma, lung and spleen from guinea pig) by sequential extraction with acetonitrile and quantified by a Waters HPLC Alliance System coupled with a ZORBAX Bonus-RP column, guard column and UV detection at 263nm. The mobile phase was 20:80 acetonitrile:ultrapure-water with 0.05% TFA. The CPZEN-45 peak was eluted at 5.1min with no interference from the inherent peaks of plasma, bronchoalveolar lavage (BAL), lung or spleen tissues. Recovery of CPZEN-45 from biological samples was >96% of the spiked amount. The limit of detection was 0.05μg/ml and the limit of quantitation was 0.29μg/ml which was more than 5 and 21 times lower than the reported minimal inhibitory concentration of CPZEN-45 (MIC=1.56μg/ml for Mycobacterium tuberculosis and 6.25μg/ml for MDR-TB, respectively). Thus, HPLC method was deemed reliable, sensitive, reproducible and accurate for the determination of CPZEN-45 concentrations in plasma, BAL, lung and spleen tissues. Therefore, this method was used in subsequent studies in the guinea pig model to determine the disposition of CPZEN-45 after administration of solutions by the IV and SC routes. Copyright © 2013 Elsevier B.V. All rights reserved.

Modeling Aquatic Toxicity through Chromatographic Systems.

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Fernández-Pumarega, Alejandro; Amézqueta, Susana; Farré, Sandra; Muñoz-Pascual, Laura; Abraham, Michael H; Fuguet, Elisabet; Rosés, Martí

2017-08-01

Environmental risk assessment requires information about the toxicity of the growing number of chemical products coming from different origins that can contaminate water and become toxicants to aquatic species or other living beings via the trophic chain. Direct toxicity measurements using sensitive aquatic species can be carried out but they may become expensive and ethically questionable. Literature refers to the use of chromatographic measurements that correlate to the toxic effect of a compound over a specific aquatic species as an alternative to get toxicity information. In this work, we have studied the similarity in the response of the toxicity to different species and we have selected eight representative aquatic species (including tadpoles, fish, water fleas, protozoan, and bacteria) with known nonspecific toxicity to chemical substances. Next, we have selected four chromatographic systems offering good perspectives for surrogation of the eight selected aquatic systems, and thus prediction of toxicity from the chromatographic measurement. Then toxicity has been correlated to the chromatographic retention factor. Satisfactory correlation results have been obtained to emulate toxicity in five of the selected aquatic species through some of the chromatographic systems. Other aquatic species with similar characteristics to these five representative ones could also be emulated by using the same chromatographic systems. The final aim of this study is to model chemical products toxicity to aquatic species by means of chromatographic systems to reduce in vivo testing.

Measurement uncertainty of liquid chromatographic analyses visualized by Ishikawa diagrams.

Science.gov (United States)

Meyer, Veronika R

2003-09-01

Ishikawa, or cause-and-effect diagrams, help to visualize the parameters that influence a chromatographic analysis. Therefore, they facilitate the set up of the uncertainty budget of the analysis, which can then be expressed in mathematical form. If the uncertainty is calculated as the Gaussian sum of all uncertainty parameters, it is necessary to quantitate them all, a task that is usually not practical. The other possible approach is to use the intermediate precision as a base for the uncertainty calculation. In this case, it is at least necessary to consider the uncertainty of the purity of the reference material in addition to the precision data. The Ishikawa diagram is then very simple, and so is the uncertainty calculation. This advantage is given by the loss of information about the parameters that influence the measurement uncertainty.

Estimations of temperature deviations in chromatographic columns using isenthalpic plots. I. Theory for isocratic systems.

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Tarafder, Abhijit; Iraneta, Pamela; Guiochon, Georges; Kaczmarski, Krzysztof; Poe, Donald P

2014-10-31

We propose to use constant enthalpy or isenthalpic diagrams as a tool to estimate the extent of the temperature variations caused by the mobile phase pressure drop along a chromatographic column, e.g. of its cooling in supercritical fluid and its heating in ultra-performance liquid chromatography. Temperature strongly affects chromatographic phenomena. Any of its variations inside the column, whether intended or not, can lead to significant changes in separation performance. Although instruments use column ovens in order to keep constant the column temperature, operating conditions leading to a high pressure drop may cause significant variations of the column temperature, both in the axial and the radial directions, from the set value. Different ways of measuring these temperature variations are available but they are too inconvenient to be employed in many practical situations. In contrast, the thermodynamic plot-based method that we describe here can easily be used with only a ruler and a pencil. They should be helpful in developing methods or in analyzing results in analytical laboratories. Although the most effective application area for this approach should be SFC (supercritical fluid chromatography), it can be applied to any chromatographic conditions in which temperature variations take place along the column due to the pressure drop, e.g. in ultra-high pressure liquid chromatography (UHPLC). The method proposed here is applicable to isocractic conditions only. Copyright © 2014 Elsevier B.V. All rights reserved.

Rapid determination of some psychotropic drugs in complex matrices by tandem dispersive liquid-liquid microextraction followed by high performance liquid chromatography.

Science.gov (United States)

Asghari, Alireza; Fahimi, Ebrahim; Bazregar, Mohammad; Rajabi, Maryam; Boutorabi, Leila

2017-05-01

Simple and rapid determinations of some psychotropic drugs in some pharmaceutical wastewater and human plasma samples were successfully accomplished via the tandem dispersive liquid-liquid microextraction combined with high performance liquid chromatography-ultraviolet detection (TDLLME-HPLC-UV). TDLLME of the three psychotropic drugs clozapine, chlorpromazine, and thioridazine was easily performed through two consecutive dispersive liquid-liquid microextractions. By performing this convenient method, proper sample preconcentrations and clean-ups were achieved in just about 7min. In order to achieve the best extraction efficiency, the effective parameters involved were optimized. The optimal experimental conditions consisted of 100μL of CCl 4 (as the extraction organic solvent), and the pH values of 13 and 2 for the donor and acceptor phases, respectively. Under these optimum experimental conditions, the proposed TDLLME-HPLC-UV technique provided a good linearity in the range of 5-3000ngmL -1 for the three psychotropic drugs with the correlation of determinations (R 2 s) higher than 0.996. The limits of quantification (LOQs) and limits of detection (LODs) obtained were 5.0ngmL -1 and 1.0-1.5ngmL -1 , respectively. Also the proper enrichment factors (EFs) of 96, 99, and 88 for clozapine, chlorpromazine, and thioridazine, respectively, and good extraction repeatabilities (relative standard deviations below 9.3%, n=5) were obtained. Copyright © 2017 Elsevier B.V. All rights reserved.

The counterintuitive role of extra-column volume in the determination of column efficiency and scaling of chromatographic processes

NARCIS (Netherlands)

Schultze-Jena, A.; Boon, M.A.; Bussmann, P.J.Th.; Janssen, A.E.M.; Padt, van der A.

2017-01-01

In industrial liquid separation processes chromatography often has a key function in the optimization of yield and purity. For the design of an industrial system, chromatographic processes are generally simulated using mathematical models, tested and optimized at laboratory level, and then scaled

The counterintuitive role of extra-column volume in the determination of column efficiency and scaling of chromatographic processes

NARCIS (Netherlands)

Schultze-Jena, A.; Boon, M.A.; Bussmann, P.J.T.; Janssen, A.E.M.; Padt, A. van der

2017-01-01

In industrial liquid separation processes chromatography often has a key function in the optimization of yield and purity. For the design of an industrial system, chromatographic processes are generally simulated using mathematical models, tested and optimized at laboratory level, and then scaled up

Monitoring for 99Tc in borehole waters using an extraction chromatographic resin

International Nuclear Information System (INIS)

Davis, T.M.; Nelson, D.M.; Thompson, E.G.

1993-01-01

A technique using an extraction chromatographic resin for the analysis of 99 Tc in borehole waters is presented. The method involves one pass of the sample through two resins, a rinse of the resins, then counting of one of the resins by liquid scintillation counting. The technique is intended to be used as a screening method of 99 Tc. The procedure employs commercially available materials, generates little waste and requires very little operator time

Extraction and Chromatographic Determination of Shikimic Acid in Chinese Conifer Needles with 1-Benzyl-3-methylimidazolium Bromide Ionic Liquid Aqueous Solutions

Science.gov (United States)

Chen, Fengli; Hou, Kexin; Li, Shuangyang; Zu, Yuangang; Yang, Lei

2014-01-01

An ionic liquids-based ultrasound-assisted extraction (ILUAE) method was successfully developed for extracting shikimic acid from conifer needles. Eleven 1-alkyl-3-methylimidazolium ionic liquids with different cations and anions were investigated and 1-benzyl-3-methylimidazolium bromide solution was selected as the solvent. The conditions for ILUAE, including the ionic liquid concentration, ultrasound power, ultrasound time, and liquid-solid ratio, were optimized. The proposed method had good recovery (99.37%–100.11%) and reproducibility (RSD, n = 6; 3.6%). ILUAE was an efficient, rapid, and simple sample preparation technique that showed high reproducibility. Based on the results, a number of plant species, namely, Picea koraiensis, Picea meyeri, Pinus elliottii, and Pinus banksiana, were identified as among the best resources of shikimic acid. PMID:24782942

Simple and rapid determination of norethindrone in human plasma by supported liquid extraction and ultra performance liquid chromatography with tandem mass spectrometry.

Science.gov (United States)

Gong, Zhilong; Chandler, Kiresha; Webster, Stephen; Kerley, Remy; Buist, Susan; McCort-Tipton, Melanie

2012-03-15

We report for the first time an ultra performance liquid chromatographic method with tandem mass spectrometric detection (UPLC/MS/MS) for the determination of norethindrone alone in human plasma over the concentration range of 50.0-25000 pg mL(-1) using a sample volume of 0.250 mL. Norethindrone and its internal standard (ISTD), norethindrone-(13)C(2), were extracted from human plasma by supported liquid extraction (SLE). After evaporation of the organic solvent, samples were reconstituted and analyzed on an UPLC/MS/MS system. The UPLC system used a Waters BEH C18 (100 mm × 2.1mm, 1.7 μm) column with mobile phase A of 0.05% formic acid in water:acetonitrile (65:35, v/v) and mobile phase B of 0.05% formic acid in methanol:acetonitrile (50:50, v/v). The flow rate was 0.500 mL min(-1). The method was fully validated. The inter-run accuracy and precision at the lower limit of quantitation (LLOQ), low, mid and high quality control (QC) concentration levels were 99.2-108.4% with a <8.1% CV (coefficient of variation), respectively. The validated method has been successfully applied to analysis of thousands of pharmacokinetic samples. Copyright © 2012 Elsevier B.V. All rights reserved.

Rapid separation of lanthanides and actinides on small particle based reverse phase supports

Energy Technology Data Exchange (ETDEWEB)

Datta, A.; Sivaraman, N.; Srinivasan, T.G.; Vasudeva Rao, P.R. [Chemistry Group, Indira Gandhi Centre for Atomic Research, Kalpakkam (India)

2010-07-01

This paper presents the results on the use of short columns (3-5 cm long) with small particle size (1.8 {mu}m) for high performance liquid chromatographic separation of individual lanthanides and uranium from plutonium as well as uranium from thorium to achieve rapid separations i.e. separation time as short as 3.6 min for individual lanthanides, 1 min for thorium-uranium and 4.2 min for uranium from plutonium. These advantages can be exploited to significantly reduce analysis time, liquid waste generation as well as dose to operator when radioactive samples are analysed e.g. burn-up determination. In the present work, a dynamic ion-exchange chromatographic separation technique was employed using camphor-10-sulfonic acid (CSA) as the ion-pairing reagent and {alpha}-hydroxy isobutyric acid ({alpha}-HIBA) as the complexing reagent for the isolation of individual lanthanides as well as the separation of uranium from thorium. Uranium was separated from Pu(III) as well as Pu(IV) by reverse phase HPLC technique. The reverse phase HPLC was also investigated for the isolation and quantitative determination of uranium from thorium as well as lanthanide group from uranium. The dynamic ion-exchange technique using small particle support was demonstrated for measuring the concentrations of lanthanide fission products such as La, Ce, Pr, Nd and Sm in the dissolver solution of fast reactor fuel. Similarly, the assay of uranium in the dissolver solution of fast reactor was carried out using reverse phase HPLC technique. The rapid separation technique using reverse phase HPLC was also demonstrated for separation of lanthanides as a group from uranium matrix; samples of LiCl-KCl eutectic salt containing chlorides of lanthanides in uranium matrix (typically 1: 2000) were analysed. (orig.)

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...

Rapid and Low-cost Prototyping of Medical Devices Using 3D Printed Molds for Liquid Injection Molding

Science.gov (United States)

Chung, Philip; Heller, J. Alex; Etemadi, Mozziyar; Ottoson, Paige E.; Liu, Jonathan A.; Rand, Larry; Roy, Shuvo

2014-01-01

Biologically inert elastomers such as silicone are favorable materials for medical device fabrication, but forming and curing these elastomers using traditional liquid injection molding processes can be an expensive process due to tooling and equipment costs. As a result, it has traditionally been impractical to use liquid injection molding for low-cost, rapid prototyping applications. We have devised a method for rapid and low-cost production of liquid elastomer injection molded devices that utilizes fused deposition modeling 3D printers for mold design and a modified desiccator as an injection system. Low costs and rapid turnaround time in this technique lower the barrier to iteratively designing and prototyping complex elastomer devices. Furthermore, CAD models developed in this process can be later adapted for metal mold tooling design, enabling an easy transition to a traditional injection molding process. We have used this technique to manufacture intravaginal probes involving complex geometries, as well as overmolding over metal parts, using tools commonly available within an academic research laboratory. However, this technique can be easily adapted to create liquid injection molded devices for many other applications. PMID:24998993

Post-synthetic modification of MIL-101(Cr) with pyridine for high-performance liquid chromatographic separation of tocopherols.

Science.gov (United States)

Yang, Fang; Yang, Cheng-Xiong; Yan, Xiu-Ping

2015-05-01

Effective separation of tocopherols is challenging and significant due to their structural similarity and important biological role. Here we report the post-synthetic modification of metal-organic framework (MOF) MIL-101(Cr) with pyridine for high-performance liquid chromatographic (HPLC) separation of tocopherols. Baseline separation of four tocopherols was achieved on a pyridine-grafted MIL-101(Cr) packed column within 10 min using hexane/isopropanol (96:4, v/v) as the mobile phase at a flow rate of 0.5 mL min(-1). The pyridine-grafted MIL-101(Cr) packed column gave high column efficiency (85,000 plates m(-1) for δ-tocopherol) and good precision (0.2-0.3% for retention time, 1.8-3.4% for peak area, 2.6-2.7% for peak height), and also offered much better performance than unmodified MIL-101(Cr) and commercial amino-bonded silica packed column for HPLC separation of tocopherols. The results not only show the promising application of pyridine-grafted MIL-101(Cr) as a novel stationary phase for HPLC separation of tocopherols, but also reveal a facile post-modification of MOFs to expand the application of MOFs in separation sciences. Copyright © 2015 Elsevier B.V. All rights reserved.

Assessment of the chromatographic lipophilicity of eight cephalosporins on different stationary phases.

Science.gov (United States)

Dąbrowska, Monika; Starek, Małgorzata; Komsta, Łukasz; Szafrański, Przemysław; Stasiewicz-Urban, Anna; Opoka, Włodzimierz

2017-04-01

The retention behaviors were investigated for a series of eight cephalosporins in thin-layer chromatography (TLC) using stationary phases of RP-2, RP-8, RP-18, NH 2 , DIOL, and CN chemically bonded silica gel. Additionally, various binary mobile phases (water/methanol and water/acetone) were used in different volume proportions. The retention behavior of the analyzed molecules was defined by R M0 constant. In addition, reversed phase high performance liquid chromatography (RP-HPLC) was performed in lipophilicity studies by using immobilized artificial membrane (IAM) stationary phase. Obtained chromatographic data (R M0 and logk' IAM ) were correlated with the lipophilicity, expressed as values of the log calculated (logP calc ) and experimental (logP exp(shake-flask) ) partition coefficient. Principal component analysis (PCA) was applied in order to obtain an overview of similarity or dissimilarity among the analyzed compounds. Hierarchical cluster analysis (HCA) was performed to compare the separation characteristics of the applied stationary phases. This study was undertaken to identify the best chromatographic system and chromatographic data processing method to enable the prediction of logP values. A comprehensive chromatographic investigation into the retention of the analyzed cephalosporins revealed a similar behavior on RP-18, RP-8 and CN stationary phases. The weak correlations obtained between experimental and certain computed lipophilicity indices revealed that R M0 and PC1/RM are relevant lipophilicity parameters and the RP-8, CN and RP-18 plates are appropriate stationary phases for lipophilicity investigation, whereas computational approaches still cannot fully replace experimentation. Copyright © 2017 Elsevier B.V. All rights reserved.

Chromatographic and electrophoretic approaches in ink analysis.

Science.gov (United States)

Zlotnick, J A; Smith, F P

1999-10-15

Inks are manufactured from a wide variety of substances that exhibit very different chemical behaviors. Inks designed for use in different writing instruments or printing methods have quite dissimilar components. Since the 1950s chromatographic and electrophoretic methods have played important roles in the analysis of inks, where compositional information may have bearing on the investigation of counterfeiting, fraud, forgery, and other crimes. Techniques such as paper chromatography and electrophoresis, thin-layer chromatography, high-performance liquid chromatography, gas chromatography, gel electrophoresis, and the relatively new technique of capillary electrophoresis have all been explored as possible avenues for the separation of components of inks. This paper reviews the components of different types of inks and applications of the above separation methods are reviewed.

Liquid phase chromatography on microchips

DEFF Research Database (Denmark)

Kutter, Jörg Peter

2012-01-01

explosive development of, in particular, chromatographic separation systems on microchips, has, however, slowed down in recent years. This review takes a closer, critical look at how liquid phase chromatography has been implemented in miniaturized formats over the past several years, what is important...

New high performance liquid chromatographic method for simultaneous determination of diclofenac and meloxicam in oral formulation of liposomes and human plasma

International Nuclear Information System (INIS)

Madni, A.; Ahmad, M.; Usman, M.; Zubair, M.M.; Shoiab, H.M.; Khan, S.A.; Qureshi, M.S.

2010-01-01

A new, easy and consistent reversed-phase high-performance liquid chromatographic method with diode array detection has been developed and validated for the simultaneous determination of diclofenac potassium (DP) and meloxicam (MLX) in liposome, marketed brands and human plasma. Microextraction method based on liquid-liquid extraction principal was used to extract drug from plasma matrix. The optimized mobile phase was used in the molar ratio of 20:20:60 (v/v/v) mixture of acetonitrile, methanol and 20 x 10/sup -3/ M potassium dihydrogen phosphate buffer (pH 3.7), pumped at an optimized flow rate of 1.0 mL.min/sup -1/. The linearity was performed in the concentration range of 15 ng.mL/sup -1/ to 10 mu g.mL/sup -1/ with gamma/sup 2/ of 0.9989 +- 0.13 and 0.9979 +- 0.11 (n = 6) for DP and MLX, respectively. The assay was repeatable at concentration levels of 10 ng.mL/sup -1/, 1 mu g.mL/sup -1/ and 10 mu g.mL/sup -1/ with coefficient of variation of 0.168 - 0.603% for 10 ng.mL-1 (DP), 15 ng.mL/sup -/1 (MLX) and 1 mu g.mL/sup -1/ and 10 mu g.mL/sup -1/ for DP and MLX. The LOD values were 3 and 5 ng.mL/sup -1/, while values of LOQ were 10 and 15 ng.mL/sup =11, for DP and MLX. The present method is applicable in routine quality control operations, advanced drug delivery formulations (Liposomes) and in human Plasma samples for pharmacokinetics and bioequivalence studies. (author)

A rapid method to estimate uranium using ionic liquid as extracting agent from basic aqueous media

International Nuclear Information System (INIS)

Prabhath Ravi, K.; Sathyapriya, R.S.; Rao, D.D.; Ghosh, S.K.

2016-01-01

Room temperature ionic liquids, as their name suggests are salts with a low melting point typically less than 100 °C and exist as liquid at room temperature. The common cationic parts of ionic liquids are imidazolium, pyridinium, pyrrolidinium, quaternary ammonium, or phosphonium ions, and common anionic parts are chloride, bromide, boron tetrafluorate, phosphorous hexafluorate, triflimide etc. The physical properties of ionic liquids can be tuned by choosing appropriate cations with differing alkyl chain lengths and anions. Application of ionic liquids in organic synthesis, liquid-liquid extractions, electrochemistry, catalysis, speciation studies, nuclear reprocessing is being studied extensively in recent times. In this paper a rapid method to estimate the uranium content in aqueous media by extraction with room temperature ionic liquid tricaprylammoniumthiosalicylate ((A- 336)(TS)) followed by liquid scintillation analysis is described. Re-extraction of uranium from ionic liquid phase to aqueous phase was also studied

In-syringe dispersive liquid-liquid microextraction with liquid chromatographic determination of synthetic pyrethroids in surface water

Directory of Open Access Journals (Sweden)

Saeed S. Albaseer

2012-03-01

Full Text Available An indigenously fabricated in laboratory glass syringe was used for in-syringe dispersive liquid-liquid microextraction (is-DLLME and preconcentration of synthetic pyrethroids (SPs from surface waters suitable for their determination by high performance liquid chromatography. In contrast to classical DLLME, is-DLLME allows the use of lighter-than-water organic solvents and the analysis of environmental contaminants’ samples without prior filtration, which is of great importance due to the high affinity of pyrethroids to adsorb to solid particulates present in environmental samples. The effects of various parameters on the extraction efficiency were evaluated and optimized systemically using one-factor-at-a-time method (OFAT and statistically using full factorial design (24. Three SPs (viz.; cypermethrin, resmethrin and permethrin were analyzed. The method showed good accuracy with RSD% in the range of of 4.8–6.9%. The method detection limits of the three pesticides ranged from 0.14 to 0.16 ng mL-1. The proposed method was applied for the determination of synthetic pyrethroids in lake water

Rapid chromatographic determination of caseins in milk with photometric and fluorimetric detection using a hydrophobic monolithic column.

Science.gov (United States)

Ramírez-Palomino, P; Fernández-Romero, J M; Gómez-Hens, A

2014-01-01

Reverse-phase liquid chromatographic methods using a hydrophobic C18 monolithic column and on-line photometric and fluorimetric detection for the determination of the major casein (CN) proteins in milk are presented. The separation of αs1-CN, αs2-CN, β-CN and κ-CN was achieved in only five minutes. Fluorimetric detection enabled better analytical results than photometric detection. Thus, the dynamic ranges of the calibration graphs and detection limits obtained using fluorimetric detection were (mgmL(-)(1)): αs1-CN (0.74-10.0, 0.22), αs2-CN (0.15-10.0, 0.045), β-CN (0.68-10.0, 0.20) and κ-CN (0.21-10.0, 0.06). The analytical features of the photometric method, which does not allow the quantification of β-casein, were (mgmL(-)(1)): αs1-CN (1.5-9.0, 0.45), αs2-CN (1.4-10.0, 0.43) and κ-CN (0.4-9.0, 0.12). Precision data, expressed as relative standard deviation, ranged between 0.6% and 5.3% for the fluorimetric method and between 2.4% and 6.2% for the photometric method. Both methods were applied to the analysis of three different milk samples, obtaining recoveries in the ranges of 86.6-103.2% and 92.0-106.5% using fluorimetric and photometric detection, respectively. Copyright © 2013 Elsevier Ltd. All rights reserved.

Principles of qualitative analysis in the chromatographic context.

Science.gov (United States)

Valcárcel, M; Cárdenas, S; Simonet, B M; Carrillo-Carrión, C

2007-07-27

This article presents the state of the art of qualitative analysis in the framework of the chromatographic analysis. After establishing the differences between two main classes of qualitative analysis (analyte identification and sample classification/qualification) the particularities of instrumental qualitative analysis are commented on. Qualitative chromatographic analysis for sample classification/qualification through the so-called chromatographic fingerprint (for complex samples) or the volatiles profile (through the direct coupling headspace-mass spectrometry using the chromatograph as interface) is discussed. Next, more technical exposition of the qualitative chromatographic information is presented supported by a variety of representative examples.

Multiple-channel ultra-violet absorbance detector for two-dimensional chromatographic separations.

Science.gov (United States)

Lynch, Kyle B; Yang, Yu; Ren, Jiangtao; Liu, Shaorong

2018-05-01

In recent years, much research has gone into developing online comprehensive two-dimensional liquid chromatographic systems allowing for high peak capacities in comparable separation times to that of one-dimensional liquid chromatographic systems. However, the speed requirements in the second dimension (2nd-D) still remain one challenge for complex biological samples due to the current configuration of two column/two detector systems. Utilization of multiple 2nd-D columns can mitigate this challenge. To adapt this approach, we need a multiple channel detector. Here we develop a versatile multichannel ultraviolet (UV) light absorbance detector that is capable of simultaneously monitoring separations in 12 columns. The detector consists of a deuterium lighthouse, a flow cell assembly (a 13-channel flow cell fitted with a 13-photodiode-detection system), and a data acquisition and monitoring terminal. Through the use of a custom high optical quality furcated fiber to improve light transmission, precise machining of a flow cell to reduce background stray light through precision alignment, and sensitive electronic circuitry to reduce electronic noise through an active low pass filter, the background noise level is measured in the tens of µAU. We obtain a linear dynamic range of close to three orders of magnitude. Compared to a commercialized multichannel UV light absorbance detector like the Waters 2488 UV/Vis, our device provides an increase in channel detection while residing within the same noise region and linear range. Copyright © 2018 Elsevier B.V. All rights reserved.

Development and validation of a rapid ultra-high performance liquid chromatography diode array detector method for Vitex agnus-castus.

Science.gov (United States)

Högner, C; Sturm, S; Seger, C; Stuppner, H

2013-05-15

A rapid ultra-high performance liquid chromatography diode array detector (UHPLC-DAD) method was developed and validated for the simultaneous determination of all classes of non-volatile phytochemicals (iridoids, flavonoids and diterpenes) in Vitex agnus-castus (Lamiaceae) fruits, a traditional medicinal plant used against premenstrual symptoms (PMS) and other disorders. Seven marker compounds, 3,4-dihydroxybenzoic acid, p-hydroxybenzoic acid, agnuside, 5-hydroxykaempferol-3,6,7,4'-tetramethylether, 1,2-dibenzoic acid glucose, methoxy-vitexilactone, and vitetrifolin D were isolated from the methanol extract of V. agnus-castus to be used as reference substances. Chromatographic separation was performed on a Zorbax Eclipse XDB-C18 (50mm×2.1mm) UHPLC column with 1.8μm particle size, within 20min. A solvent gradient from 0.5% acetic acid to acetonitrile at a flow rate of 0.6mL/min was used as mobile phase. Analyte detection and quantification was realized at 210nm and 260nm. The UHPLC-DAD assay was validated for the quantitative analysis of agnuside, isovitexin, casticin, 5-hydroxykaempferol-3,6,7,4'-tetramethylether and vitetrifolin D. It was found to be specific, accurate, precise, and reproducible for the quantification of these compound within a concentration range of 0.7-500.0μg/mL for casticin and 5-hydroxykaempferol-3,6,7,4'-tetramethylether, 1.4-1000.0μg/mL for isovitexin and agnuside, and 12.4-1000.0μg/mL for vitetrifolin D. Intra- and inter-day variations showed relative standard deviations (RSD) of less than 3.9% and 6.4%, respectively. Tentatively assignment of 62 chromatographic features found in the UHPLC-DAD assay was carried out by coupling the UHPLC instrument to a quadrupole time-of-flight mass spectrometer via an electrospray ionization interface (ESI-QTOF-MS) operated in positive and negative ion mode. By using the established quantitative UHPLC-DAD assay to asses agnuside, isovitexin, casticin, 5-hydroxykaempferol-3,6,7,4'-tetramethylether and

Gas chromatographic determination of calcium propionate added as preservative to bread.

Science.gov (United States)

Lamkin, W M; Unruh, N C; Pomeranz, Y

1987-01-01

A simple and rapid gas chromatographic procedure was developed for determining low concentrations of propionate added as a preservative to bread. A bread sample to be analyzed was ground in a meat grinder with a 3 mm hole plate and finely divided by rubbing through a No. 8 sieve. The propionate was then extracted into 0.050M formic acid in a blender at low speed for 5 min, and an aliquot of a filtrate was analyzed directly by gas chromatography. Chromatographic separation was accomplished on a Carbopack C column coated with 0.3% (w/w) Carbowax 20M and 0.1% (w/w) phosphoric acid. Less than 0.2 ppm propionic acid could be detected in the aqueous extract. Over the range of 0.03-0.23% calcium propionate, average relative error was -1.20% with an average coefficient of variation of 2.02%.

Automation of an ion chromatograph for precipitation analysis with computerized data reduction

Science.gov (United States)

Hedley, Arthur G.; Fishman, Marvin J.

1982-01-01

Interconnection of an ion chromatograph, an autosampler, and a computing integrator to form an analytical system for simultaneous determination of fluoride, chloride, orthophosphate, bromide, nitrate, and sulfate in precipitation samples is described. Computer programs provided with the integrator are modified to implement ionchromatographic data reduction and data storage. The liquid-flow scheme for the ion chromatograph is changed by addition of a second suppressor column for greater analytical capacity. An additional vave enables selection of either suppressor column for analysis, as the other column is regenerated and stabilized with concentrated eluent.Minimum limits of detection and quantitation for each anion are calculated; these limits are a function of suppressor exhaustion. Precision for replicate analyses of six precipitation samples for fluoride, chloride, orthophosphate, nitrate, and sulfate ranged from 0.003 to 0.027 milligrams per liter. To determine accuracy of results, the same samples were spiked with known concentrations of the above mentioned anions. Average recovery was 108 percent.

Liquid chromatographic determination of para-toluenesulfonamide in edible fillet tissues from three species of fish

Science.gov (United States)

Meinertz, J.R.; Schmidt, L.J.; Stehly, G.R.; Gingerich, W.H.

1999-01-01

Chloramine-T (N-sodium-N-chloro-p-toluene-sulfonamide) is a candidate therapeutic drug for treating bacterial gill disease, a predominant disease of a variety of fish species. Research has been initiated to obtain the U.S. Food and Drug Administration's (FDA) approval for the use of chloramine-T on a variety of fish species. An attribute of a therapeutic aquaculture drug that must be characterized before the FDA approves its use is depletion of the drug's marker residue (the drug's parent compound or metabolite of highest concentration in an edible tissue). Para-Toluenesulfonamide (p-TSA) is the primary degradation product and marker residue for chloramine-T in rainbow trout. To conduct residue depletion studies for chloramine-T in fish, a robust analytical method sensitive and specific for p-TSA residues in edible fillet tissue from a variety of fish was required. Homogenized fillet tissues from rainbow trout (Oncorhynchus mykiss), walleye (Stizostedion vitreum), and channel catfish (Ictalurus punctatus) were fortified at nominal p-TSA concentrations of 17, 67, 200, 333, and 1000 ng/g. Samples were analyzed by isocratic reversed-phase liquid chromatography (LC) with absorbance detection at 226 nm. Mean recoveries of p-TSA ranged from 77 to 93.17%; relative standard deviations ranged from 1.5 to 14%; method quantitation limits ranged from 13 to 18 ng/g; and method detection limits ranged from 3.8 to 5.2 ng/g. The LC parameters produced p-TSA peaks without coelution of endogenous compounds and excluded chromatographic interference from at least 20 chemicals and drugs of potential use in aquaculture.

[Simultaneous determination of four common nonprotein nitrogen substances in urine by high performance liquid chromatography].

Science.gov (United States)

Ma, Yuhua; Huang, Dongqun; Zhang, Rui; Xu, Shiru; Feng, Shun

2013-11-01

A high performance liquid chromatographic (HPLC) method was proposed to simultaneously determine four common nonprotein nitrogen substances, including creatine (Cr), creatinine (Cn), uric acid (Ua) and pseudouridine (Pu) in urine. After proteins being removed by acetone precipitation method, freeze drying and redissolving, the urine samples were analyzed by HPLC. Chromatographic separation was performed on a Waters RP18 Column (150 mm x 4.60 mm, 3.5 microm) in gradient elution mode using 10.0 mmol/L KH2PO4 solution (pH 4.78) and acetonitrile as mobile phases at a flow rate of 0.8 mL/min. The samples were detected at 220 nm. Rapid separation was achieved within 7 min. Under the optimized conditions, good linearities of four common nonprotein nitrogen substances were obtained in the range of 0.1-250 mg/L. The detection limits were 9.31 (Cr), 26.19 (Cn), 4.70 (Ua), an 6.30 (Pu) microg/L and the recoveries were in the range of 81%-111% with the relative standar deviations of 0.23%-2.78% (n = 3). The results demonstrate that this method is simple, rapid and accurate with good reproducibility, and can provide early diagnosis and preliminary judgment for type 2 diabetes mellitus (T2DM) patients with renal damage.

UPLC and LC-MS studies on degradation behavior of irinotecan hydrochloride and development of a validated stability-indicating ultra-performance liquid chromatographic method for determination of irinotecan hydrochloride and its impurities in pharmaceutical dosage forms.

Science.gov (United States)

Kumar, Navneet; Sangeetha, Dhanaraj; Reddy, Sunil P

2012-10-01

The objective of the current investigation was to study the degradation behavior of irinotecan hydrochloride under different International Conference on Harmonization (ICH) recommended stress conditions using ultra-performance liquid chromatography and liquid chromatography-mass spectrometry and to establish a validated stability-indicating reverse-phase ultra-performance liquid chromatographic method for the quantitative determination of irinotecan hydrochloride and its seven impurities and degradation products in pharmaceutical dosage forms. Irinotecan hydrochloride was subjected to the stress conditions of oxidative, acid, base, hydrolytic, thermal and photolytic degradation. Irinotecan hydrochloride was found to degrade significantly in oxidative and base hydrolysis and photolytic degradation conditions. The degradation products were well resolved from the main peak and its impurities, thus proving the stability-indicating power of the method. Chromatographic separation was achieved on a Waters Acquity BEH C8 (100 × 2.1 mm) 1.7-µm column with a mobile phase containing a gradient mixture of solvent A (0.02M KH(2)PO(4) buffer, pH 3.4) and solvent B (a mixture of acetonitrile and methanol in the ratio of 62:38 v/v). The mobile phase was delivered at a flow rate of 0.3 mL/min with ultraviolet detection at 220 nm. The run time was 8 min, within which irinotecan and its seven impurities and degradation products were satisfactorily separated. The developed method was validated as per ICH guidelines with respect to specificity, linearity, limit of detection, limit of quantification, accuracy, precision and robustness. This method was also suitable for the assay determination of irinotecan hydrochloride in pharmaceutical dosage forms.

Chromatographic Separations of Enantiomers and Underivatized Oligosaccharides

Energy Technology Data Exchange (ETDEWEB)

Liu, Ying [Iowa State Univ., Ames, IA (United States)

2004-01-01

My graduate research has focused on separation science and bioanalytical analysis, which emphasized in method development. It includes three major areas: enantiomeric separations using high performance liquid chromatography (HPLC), Super/subcritical fluid chromatography (SFC), and capillary electrophoresis (CE); drug-protein binding behavior studies using CE; and carbohydrate analysis using liquid chromatograph-electrospray ionization mass spectrometry (LC-ESI-MS). Enantiomeric separations continue to be extremely important in the pharmaceutical industry. An in-depth evaluation of the enantiomeric separation capabilities of macrocyclic glycopeptides CSPs with SFC mobile phases was investigated using a set of over 100 chiral compounds. It was found that the macrocyclic based CSPs were able to separate enantiomers of various compounds with different polarities and functionalities. Seventy percent of all separations were achieved in less than 4 min due to the high flow rate (4.0 ml/min) that can be used in SFC. Drug-protein binding is an important process in determining the activity and fate of a drug once it enters the body. Two drug/protein systems have been studied using frontal analysis CE method. More sensitive fluorescence detection was introduced in this assay, which overcame the problem of low sensitivity that is common when using UV detection for drug-protein studies. In addition, the first usage of an argon ion laser with 257 nm beam coupled with CCD camera as a frontal analysis detection method enabled the simultaneous observation of drug fluorescence as well as the protein fluorescence. LC-ESI-MS was used for the separation and characterization of underivatized oligosaccharide mixtures. With the limits of detection as low as 50 picograms, all individual components of oligosaccharide mixtures (up to 11 glucose-units long) were baseline resolved on a Cyclobond I 2000 column and detected using ESI-MS. This system is characterized by high chromatographic

Chromatographic Separations of Enantiomers and Underivatized Oligosaccharides

International Nuclear Information System (INIS)

Ying Liu

2004-01-01

My graduate research has focused on separation science and bioanalytical analysis, which emphasized in method development. It includes three major areas: enantiomeric separations using high performance liquid chromatography (HPLC), Super/subcritical fluid chromatography (SFC), and capillary electrophoresis (CE); drug-protein binding behavior studies using CE; and carbohydrate analysis using liquid chromatograph-electrospray ionization mass spectrometry (LC-ESI-MS). Enantiomeric separations continue to be extremely important in the pharmaceutical industry. An in-depth evaluation of the enantiomeric separation capabilities of macrocyclic glycopeptides CSPs with SFC mobile phases was investigated using a set of over 100 chiral compounds. It was found that the macrocyclic based CSPs were able to separate enantiomers of various compounds with different polarities and functionalities. Seventy percent of all separations were achieved in less than 4 min due to the high flow rate (4.0 ml/min) that can be used in SFC. Drug-protein binding is an important process in determining the activity and fate of a drug once it enters the body. Two drug/protein systems have been studied using frontal analysis CE method. More sensitive fluorescence detection was introduced in this assay, which overcame the problem of low sensitivity that is common when using UV detection for drug-protein studies. In addition, the first usage of an argon ion laser with 257 nm beam coupled with CCD camera as a frontal analysis detection method enabled the simultaneous observation of drug fluorescence as well as the protein fluorescence. LC-ESI-MS was used for the separation and characterization of underivatized oligosaccharide mixtures. With the limits of detection as low as 50 picograms, all individual components of oligosaccharide mixtures (up to 11 glucose-units long) were baseline resolved on a Cyclobond I 2000 column and detected using ESI-MS. This system is characterized by high chromatographic

Rapid pretreatment and determination of bisphenol A in water samples based on vortex-assisted liquid-liquid microextraction followed by high-performance liquid chromatography with fluorescence detection.

Science.gov (United States)

Yang, Xiao; Diao, Chun-Peng; Sun, Ai-Ling; Liu, Ren-Min

2014-10-01

A method for the rapid pretreatment and determination of bisphenol A in water samples based on vortex-assisted liquid-liquid microextraction followed by high-performance liquid chromatography with fluorescence detection was proposed in this paper. A simple apparatus consisting of a test tube and a cut-glass dropper was designed and applied to collect the floating extraction drop in liquid-liquid microextraction when low-density organic solvent was used as the extraction solvent. Solidification and melting steps that were tedious but necessary once the low-density organic solvent used as extraction solvent could be avoided by using this apparatus. Bisphenol A was selected as model pollutant and vortex-assisted liquid-liquid microextraction was employed to investigate the usefulness of the apparatus. High-performance liquid chromatography with fluorescence detection was selected as the analytical tool for the detection of bisphenol A. The linear dynamic range was from 0.10 to 100 μg/L for bisphenol A, with good squared regression coefficient (r(2) = 0.9990). The relative standard deviation (n = 7) was 4.7% and the limit of detection was 0.02 μg/L. The proposed method had been applied to the determination of bisphenol A in natural water samples and was shown to be economical, fast, and convenient. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Versatile ligands for high-performance liquid chromatography: An overview of ionic liquid-functionalized stationary phases.

Science.gov (United States)

Zhang, Mingliang; Mallik, Abul K; Takafuji, Makoto; Ihara, Hirotaka; Qiu, Hongdeng

2015-08-05

Ionic liquids (ILs), a class of unique substances composed purely by cation and anions, are renowned for their fascinating physical and chemical properties, such as negligible volatility, high dissolution power, high thermal stability, tunable structure and miscibility. They are enjoying ever-growing applications in a great diversity of disciplines. IL-modified silica, transforming the merits of ILs into chromatographic advantages, has endowed the development of high-performance liquid chromatography (HPLC) stationary phase with considerable vitality. In the last decade, IL-functionalized silica stationary phases have evolved into a series of branches to accommodate to different HPLC modes. An up-to-date overview of IL-immobilized stationary phases is presented in this review, and divided into five parts according to application mode, i.e., ion-exchange, normal-phase, reversed-phase, hydrophilic interaction and chiral recognition. Specific attention is channeled to synthetic strategies, chromatographic behavior and separation performance of IL-functionalized silica stationary phases. Copyright © 2015 Elsevier B.V. All rights reserved.

Single-step preparation of selected biological fluids for the high performance liquid chromatographic analysis of fat-soluble vitamins and antioxidants.

Science.gov (United States)

Lazzarino, Giacomo; Longo, Salvatore; Amorini, Angela Maria; Di Pietro, Valentina; D'Urso, Serafina; Lazzarino, Giuseppe; Belli, Antonio; Tavazzi, Barbara

2017-12-08

Fat-soluble vitamins and antioxidants are of relevance in health and disease. Current methods to extract these compounds from biological fluids mainly need use of multi-steps and multi organic solvents. They are time-consuming and difficult to apply to treat simultaneously large sample number. We here describe a single-step, one solvent extraction of fat-soluble vitamins and antioxidants from biological fluids, and the chromatographic separation of all-trans-retinoic acid, 25-hydroxycholecalciferol, all-trans-retinol, astaxanthin, lutein, zeaxanthin, trans-β-apo-8'-carotenal, γ-tocopherol, β-cryptoxanthin, α-tocopherol, phylloquinone, lycopene, α-carotene, β-carotene and coenzyme Q 10 . Extraction is obtained by adding one volume of biological fluid to two acetonitrile volumes, vortexing for 60s and incubating for 60min at 37°C under agitation. HPLC separation occurs in 30min using Hypersil C18, 100×4.6mm, 5μm particle size column, gradient from 70% methanol+30% H 2 O to 100% acetonitrile, flow rate of 1.0ml/min and 37°C column temperature. Compounds are revealed using highly sensitive UV-VIS diode array detector. The HPLC method suitability was assessed in terms of sensitivity, reproducibility and recovery. Using the present extraction and chromatographic conditions we obtained values of the fat-soluble vitamins and antioxidants in serum from 50 healthy controls similar to those found in literature. Additionally, the profile of these compounds was also measured in seminal plasma from 20 healthy fertile donors. Results indicate that this simple, rapid and low cost sample processing is suitable to extract fat-soluble vitamins and antioxidants from biological fluids and can be applied in clinical and nutritional studies. Copyright © 2017 Elsevier B.V. All rights reserved.

Quantitative Analysis of Matrine in Liquid Crystalline Nanoparticles by HPLC

Directory of Open Access Journals (Sweden)

Xinsheng Peng

2014-01-01

Full Text Available A reversed-phase high-performance liquid chromatographic method has been developed to quantitatively determine matrine in liquid crystal nanoparticles. The chromatographic method is carried out using an isocratic system. The mobile phase was composed of methanol-PBS(pH6.8-triethylamine (50 : 50 : 0.1% with a flow rate of 1 mL/min with SPD-20A UV/vis detector and the detection wavelength was at 220 nm. The linearity of matrine is in the range of 1.6 to 200.0 μg/mL. The regression equation is y=10706x-2959 (R2=1.0. The average recovery is 101.7%; RSD=2.22%  (n=9. This method provides a simple and accurate strategy to determine matrine in liquid crystalline nanoparticle.

Separative analyses of a chromatographic column packed with a core-shell adsorbent for lithium isotope separation

International Nuclear Information System (INIS)

Sugiyama, T.; Sugura, K.; Enokida, Y.; Yamamoto, I.

2015-01-01

Lithium-6 is used as a blanket material for sufficient tritium production in DT fueled fusion reactors. A core-shell type adsorbent was proposed for lithium isotope separation by chromatography. The mass transfer model in a chromatographic column consisted of 4 steps, such as convection and dispersion in the column, transfer through liquid films, intra-particle diffusion and and adsorption or desorption at the local adsorption sites. A model was developed and concentration profiles and time variation in the column were numerically simulated. It became clear that core-shell type adsorbents with thin porous shell were saturated rapidly relatively to fully porous one and established a sharp edge of adsorption band. This is very important feature because lithium isotope separation requires long-distance development of adsorption band. The values of HETP (Height Equivalent of a Theoretical Plate) for core-shell adsorbent packed column were estimated by statistical moments of the step response curve. The value of HETP decreased with the thickness of the porous shell. A core-shell type adsorbent is, then, useful for lithium isotope separation. (authors)

UHPLC: The Greening Face of Liquid Chromatography.

Science.gov (United States)

Cielecka-Piontek, Judyta; Zalewski, Przemysław; Jelińska, Anna; Garbacki, Piotr

2013-01-01

Pharmaceutical analysis based on chromatographic separation is an important part of studies aimed at developing routine quality analysis of drugs. High-performance liquid chromatography (HPLC) is one of the main analytical techniques recommended for drug analysis. Although it meets many criteria vital for analysis, it is time-consuming and uses a relatively high amount of organic solvents compared to other analytical techniques. Recently, Ultra-high-performance liquid chromatography (UHPLC) has been frequently proposed as an alternative to HPLC, which means introducing an environment-friendly approach to drug analysis achieved by reducing the consumption of solvents. It also offers greater chromatographic resolution and higher sensitivity as well as requiring less time due to faster analysis. This review focuses on the basics of UHPLC, compares that technique with HPLC and discusses the possibilities of applying UHPLC for the analysis of different pharmaceuticals and biopharmaceuticals.

Rapid determination of some beta-blockers in complicated matrices by tandem dispersive liquid-liquid microextraction followed by high performance liquid chromatography.

Science.gov (United States)

Hemmati, Maryam; Asghari, Alireza; Bazregar, Mohammad; Rajabi, Maryam

2016-11-01

In this research work, an efficient tandem dispersive liquid-liquid microextraction (TDLLME) procedure coupled with high performance liquid chromatography-ultraviolet detection (HPLC-UV) was successfully applied for the determination of beta-blockers in human plasma and pharmaceutical wastewater samples. High clean-up and preconcentration factor are easily and rapidly feasible via this novel, cheap, and safe microextraction method, leading to high quality experimental data. It consists of two sequential dispersive liquid-liquid microextraction methods, accomplished via air/ultrasonic agitation and air agitation, respectively. In order to enrich the optimal values for the mentioned procedures, the Box-Behnken design (BBD) combined with the desirability function (DF) was used. The optimum values were found to be 11.0 % (w/v) of the salt amount, an initial pH value of 12.0, 103 μL of organic extractant phase, and 45 μL of aqueous extractant phase with pH value of 2.0, resulted in reasonable recovery percentages with a logical desirability. Under optimal experimental conditions, good linear ranges (3-2000 ng mL -1 for metoprolol and 2.5-2500 ng mL -1 for propranolol with the correlation of determinations (R 2 s) higher than 0.99) and low limits of detection (0.8 and 1.0 ng mL -1 for propranolol and metoprolol, respectively) were obtainable. Also, TDLLME-HPLC-UV provided good proper repeatabilities (relative standard deviations (RSDs) below 5.7 %, n = 3) and high enrichment factors (EFs) of 75-100. Graphical abstract TDLLME of beta-blockers from complicated matrices.

Homogeneous nucleation ahead of the solid-liquid interface during rapid solidification of binary alloys

International Nuclear Information System (INIS)

Smith, P.M.; Elmer, J.W.

1996-01-01

In recent rapid solidification experiments on Al-5%Be alloys, a Liquid Phase Nucleation (LPN) model was developed to explain the formation of periodic arrays of randomly-oriented Be-rich particles in an Al-rich matrix. In the LPN model, Be droplets were assumed to nucleate in the liquid ahead of the solid-liquid interface, but no justification for this was given. Here the authors present a model which considers the geometric constraints (imposed by proximity to the interface) on the number of solute atoms available to form a nucleus. Calculations based on this model predict that nucleation of second-phase particles can be most likely a short distance ahead of the interface in immiscible binary systems such as Al-Be. As part of the nucleation calculations, a semi-empirical method of calculating solid-liquid surface tensions in binary systems was developed, and is presented in the Appendix

Quantification of anthocyanins in commercial black currant juices by simple high-performance liquid chromatography. Investigation of their pH stability and antioxidative potency

DEFF Research Database (Denmark)

Nielsen, Inge Lise F.; Ravn-Haren, Gitte; Magnussen, Eva Loftin

2003-01-01

(HPLC) method. The method was validated, and quantification of anthocyanins in 13 commercially available black currant beverages was demonstrated. To optimize the handling of anthocyanin-containing samples, the pH-dependent stability of the anthocyanins was investigated. Four anthocyanins were incubated......Quantitative determinations of the four black currant anthocyanins, cyanidin 3-O-beta-glucoside, cyanidin 3-O-beta-rutinoside, delphinidin 3-O-beta-glucoside, and delphinidin 3-O-beta-rutinoside, were achieved in black currant juices by a rapid and sensitive high-performance liquid chromatographic...

Analysis of anti-neoplastic drug in bacterial ghost matrix, w/o/w double nanoemulsion and w/o nanoemulsion by a validated 'green' liquid chromatographic method.

Science.gov (United States)

Youssof, Abdullah M E; Salem-Bekhit, Mounir M; Shakeel, Faiyaz; Alanazi, Fars K; Haq, Nazrul

2016-07-01

The objective of the present investigation was to develop and validate a 'green' reversed phase high-performance liquid chromatography (RP-HPLC) method for rapid analysis of a cytotoxic drug 5-fluorouracil (5-FU) in bulk drug, marketed injection, water-in-oil (w/o) nanoemulsion, double water-in-oil-in-water (w/o/w) nanoemulsion and bacterial ghost (BG) matrix. The chromatography study was carried out at room temperature (25±1°C) using an HPLC system with the help of ultraviolet (UV)-visible detector. The chromatographic performance was achieved with a Nucleodur 150mm×4.6mm RP C8 column filled with 5µm filler as a static phase. The mobile phase consisted of ethyl acetate: methanol (7:3% v/v) which was delivered at a flow rate of 1.0mLmin(-1) and the drug was detected in UV mode at 254nm. The developed method was validated in terms of linearity (r(2)=0.998), accuracy (98.19-102.09%), precision (% RSD=0.58-1.17), robustness (% RSD=0.12-0.53) and sensitivity with satisfactory results. The efficiency of the method was demonstrated by the assay of the drug in marketed injection, w/o nanoemulsion, w/o/w nanoemulsion and BG with satisfactory results. The successful resolution of the drug along with its degradation products clearly established the stability-indicating nature of the proposed method. Overall, these results suggested that the proposed analytical method could be effectively applied to the routine analysis of 5-FU in bulk drug, various pharmaceutical dosage forms and BG. Copyright © 2016 Elsevier B.V. All rights reserved.

[Detection of monoamine neurotransmitters and its metabolites by high performance liquid chromatograph after pre-column derivatization of dansyl chloride column].

Science.gov (United States)

Huang, Xiao; Chen, Jia-wen; He, Li-ping; Kang, Xue-jun

2012-12-01

To develop a high performance liquid chromatography (HPLC) for detection of monoamine neurotransmitters and its metabolites after pre-column derivatization with dansyl chloride. The C(18) chromatograph column (150 mm×4.6 mm×5 µm) was selected for detection, and derived by dansyl chloride (10 mg/ml) under the condition of 50°C water bath by pH11 buffer solution. 20 µl acetic acid acetone solution (1.0 mol/L) was then mixed in for termination of the reaction. Then the solution was cooling to room temperature, 0.1 mol/L acetic acid zinc-acetonitrile-tetrahydrofuran solution was adopted for mobile phrase, with the volume ratio at 62:35:3. The flow rate was 1.0 ml/min between 0-10 min, 2.0 ml/min between 10-35 min. The ultraviolet detection wavelength was 286 nm. The above method separately detected monoamine neurotransmitters and its metabolites and evaluated the limit of detection, accurate degree and accuracy degree. The linear relations between each component was good in the range of 1 - 20 µg/ml (r = 0.999). The lowest detection limit of norepinephrine, dopamine, 5-hydroxytryptamine and the metabolites 3-methoxy-4-benzoglycols, homovanillic acid and 5-heteroauxin were separately 0.60, 0.80, 0.41, 0.21, 0.19 and 0.1 µg/ml; while the average recovery rates were between 78.5% - 95.9%, and the relative standard deviation (RSD) was 6.62%, 7.64%, 2.98%, 3.60%, 5.09% and 3.09%, respectively. In the process of selection and optimization of the chromatographic conditions, we observed the importance of metal ions to discretion, and discussed the temperature, pH of the buffer solution and dosage of dansyl chloride in derivation. Under the above conditions, the reaction was perfect, and the baseline of the detected materials thoroughly separated. The method to detect monoamine neurotransmitters and its metabolites by HPLC and pre-column derivatization with dansyl chloride was established; and this method could provide reference for the detection of polyamine by HPLC.

Ion Chromatographic Analyses of Sea Waters, Brines and Related Samples

Directory of Open Access Journals (Sweden)

Nataša Gros

2013-06-01

Full Text Available This review focuses on the ion chromatographic methods for the analyses of natural waters with high ionic strength. At the beginning a natural diversity in ionic composition of waters is highlighted and terminology clarified. In continuation a brief overview of other review articles of potential interest is given. A review of ion chromatographic methods is organized in four sections. The first section comprises articles focused on the determination of ionic composition of water samples as completely as possible. The sections—Selected Anions, Selected Cations and Metals—follow. The most essential experimental conditions used in different methods are summarized in tables for a rapid comparison. Techniques encountered in the reviewed articles comprise: direct determinations of ions in untreated samples with ion- or ion-exclusion chromatography, or electrostatic ion chromatography; matrix elimination with column-switching; pre-concentration with a chelation ion chromatography and purge-and-trap pre-concentration. Different detection methods were used: non-suppressed conductometric or suppressed conductometric, direct spectrometric or spectrometric after a post-column derivetization, and inductively coupled plasma in combination with optical emission or mass spectrometry.

Technical artifacts in chromatographic analysis of Tc-99m radiopharmaceuticals

International Nuclear Information System (INIS)

Kowalsky, R.J.; Creekmore, J.R.

1982-01-01

Technical artifacts produced during chromatographic analysis of technetium radiopharmaceuticals were investigated. Such artifacts are, we found, caused by improper spotting and drying techniques; these in turn produce spuriously high impurities in Tc-99m complexes of DTPA, MDP, PPi, and GH. The ITLC-SG/acetone system produces considerable streaking of Tc-complex if the applied spot is large and not dried before development. This results in activity in the solvent front portion of the chromatographic strip indicating falsely high levels of pertechnetate impurity. Proper drying of the applied spot eliminates the artifact. The ITLC-SG/saline system yields falsely high, hydrolyzed-reduced technetium impurities if the spot is allowed to enter the solvent during development. Correct spot placement and size eliminate this problem. Strips that are allowed to dry in room air for several minutes may indicate considerable pertechnetate impurity on the chromatogram; yet this may not actually be present in the radiopharmaceutical vial. Drying spots rapidly with hot air or in a nitrogen atmosphere before development eliminates this problem

Rapid Determination of Total Thujone in Absinthe Using 1H NMR Spectroscopy

Directory of Open Access Journals (Sweden)

Yulia B. Monakhova

2011-01-01

Full Text Available 1H NMR spectroscopy is utilized to quantify total thujone (sum of α- and β-isomers in absinthe. For sample preparation, a simple dilution with buffer is required. Thujone produces a distinct peak of the CH2 group in the cyclopentanone moiety in the 2.13–2.11 ppm range. No overlap with other typical constituents such as anethole or fenchone occurs. The detection limit of 0.3 mg/L is adequate to control the EU maximum limit. The relative standard deviation was 6%, and linearity was observed from 1 to 100 mg/L. Applicability was proven by analysis of 69 authentic absinthes. The correlation between NMR and our previous method consisting of liquid-liquid extraction followed by GC/MS was significant (P<0.0001,R=0.93. The simple and cheap NMR method can be used for rapid screening of absinthes for total thujone content while chromatographic techniques are recommended for more specific (α- and β-thujone isomers analysis if required.

UHPLC: The Greening Face of Liquid Chromatography

OpenAIRE

Cielecka-Piontek, Judyta; Zalewski, Przemys?aw; Jeli?ska, Anna; Garbacki, Piotr

2013-01-01

Pharmaceutical analysis based on chromatographic separation is an important part of studies aimed at developing routine quality analysis of drugs. High-performance liquid chromatography (HPLC) is one of the main analytical techniques recommended for drug analysis. Although it meets many criteria vital for analysis, it is time-consuming and uses a relatively high amount of organic solvents compared to other analytical techniques. Recently, Ultra-high-performance liquid chromatography (UHPLC) h...

A chromatographic objective function to characterise chromatograms with unknown compounds or without standards available.

Science.gov (United States)

Alvarez-Segura, T; Gómez-Díaz, A; Ortiz-Bolsico, C; Torres-Lapasió, J R; García-Alvarez-Coque, M C

2015-08-28

Getting useful chemical information from samples containing many compounds is still a challenge to analysts in liquid chromatography. The highest complexity corresponds to samples for which there is no prior knowledge about their chemical composition. Computer-based methodologies are currently considered as the most efficient tools to optimise the chromatographic resolution, and further finding the optimal separation conditions. However, most chromatographic objective functions (COFs) described in the literature to measure the resolution are based on mathematical models fitted with the information obtained from standards, and cannot be applied to samples with unknown compounds. In this work, a new COF based on the automatic measurement of the protruding part of the chromatographic peaks (or peak prominences) that indicates the number of perceptible peaks and global resolution, without the need of standards, is developed. The proposed COF was found satisfactory with regard to the peak purity criterion when applied to artificial peaks and simulated chromatograms of mixtures built using the information of standards. The approach was applied to mixtures of drugs containing unknown impurities and degradation products and to extracts of medicinal herbs, eluted with acetonitrile-water mixtures using isocratic and gradient elution. Copyright © 2015 Elsevier B.V. All rights reserved.

Acrylamide analysis in food by liquid chromatographic and gas chromatographic methods.

Science.gov (United States)

Elbashir, Abdalla A; Omar, Mei M Ali; Ibrahim, Wan Aini Wan; Schmitz, Oliver J; Aboul-Enein, Hassan Y

2014-01-01

Acrylamide (AA) is a compound classified as carcinogenic to humans by the International Agency for Research on Cancer. It was first discovered to be present in certain heated processed food by the Swedish National Food Administration (SNFA) and University of Stockholm in early 2002. The major pathway for AA formation in food is the Maillard reaction between reducing sugar and the amino acid asparagine at high temperature. Since the discovery of AA's presence in food, many analytical methods have been developed for determination of AA contents in different food matrices. Also, several studies have been conducted to develop extraction procedures for AA from difficult food matrices. AA is a small, highly polar molecule, which makes its extraction and analysis challenging. Many articles and reviews have been published dealing with AA in food. The aim of the review is to discuss AA formation in food, the factors affecting AA formation and removal, AA exposure assessment, AA extraction and cleanup from food samples, and analytical methods used in AA determination, such as high-performance liquid chromatography (HPLC) and gas chromatography (GC). Special attention is given to sample extraction and cleanup procedures and analytical techniques used for AA determination.

Ultra-performance liquid chromatographic determination of tocopherols and retinol in human plasma.

Science.gov (United States)

Bell, Edward C; John, Mathew; Hughes, Rodney J; Pham, Thu

2014-10-01

A rapid, selective and sensitive ultra-performance liquid chromatography method has been developed for the detection and quantification of tocopherols and retinol in human plasma. Alpha-tocopherol, gamma-tocopherol and retinol are assayed using fluorescence detection. Excitation/emission wavelengths are 295/330 nm and 325/470 nm for the analysis of both tocopherols and retinol, respectively. Retinol acetate is employed as the internal standard. The reversed-phase method incorporates gradient elution with a mobile phase consisting of methanol and acetonitrile. Separation of vitamin compounds is achieved using a bridged ethyl hybrid C18 column. The retention times for retinol, retinol acetate, gamma-tocopherol and alpha-tocopherol are 1.6, 1.8, 3.9 and 4.3 min, respectively. The limits of quantification for retinol, gamma-tocopherol and alpha-tocopherol were 0.02, 0.02 and 0.1 µg/mL, respectively. The assay method is suitable for the analysis of tocopherols and retinol in human plasma. The method may be applied following the ingestion of foods fortified with these fat-soluble vitamins. © The Author [2013]. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Assay of common sunscreen agents in suncare products by high-performance liquid chromatography on a cyanopropyl-bonded silica column.

Science.gov (United States)

Simeoni, Silvia; Tursilli, Rosanna; Bianchi, Anna; Scalia, Santo

2005-06-15

A rapid high-performance liquid chromatographic method was developed for the simultaneous assay of eight of the most common sunscreen agents (octyl-methoxycinnamate, oxybenzone, butyl-methoxydibenzoylmethane, octyl-salicilate, methylbenzylidene camphor, octyl-dimethylamminobenzoate, phenylbenzimidazole sulphonic acid and octocrylene) in sun protection products. Evaluation of the influence of different stationary phases and eluents on the separation selectivity showed that optimal resolution was obtained on a cyanopropyl-silica column eluted with methanol-acetonitrile-tetrahydrofuran-aqueous acetic acid. A small adjustment of the proposed chromatographic system (reduction in the aqueous content of the mobile phase) permitted also the determination of the extremely hydrophobic UV filter, methylene bis-benzotriazolyl tetramethylbutylphenol along with three other sunscreen agents, octyl-methoxycinnamate, oxybenzone, butyl-methoxydibenzoylmethane. Recoveries of the UV filters from the spiked formulation were between 95.7 and 103.7% and the precision of the method was better than 6.1% relative standard deviation. The developed HPLC procedure is suitable for quality control and photostability analyses of commercial suncare products.

Batch-to-batch quality consistency evaluation of botanical drug products using multivariate statistical analysis of the chromatographic fingerprint.

Science.gov (United States)

Xiong, Haoshu; Yu, Lawrence X; Qu, Haibin

2013-06-01

Botanical drug products have batch-to-batch quality variability due to botanical raw materials and the current manufacturing process. The rational evaluation and control of product quality consistency are essential to ensure the efficacy and safety. Chromatographic fingerprinting is an important and widely used tool to characterize the chemical composition of botanical drug products. Multivariate statistical analysis has showed its efficacy and applicability in the quality evaluation of many kinds of industrial products. In this paper, the combined use of multivariate statistical analysis and chromatographic fingerprinting is presented here to evaluate batch-to-batch quality consistency of botanical drug products. A typical botanical drug product in China, Shenmai injection, was selected as the example to demonstrate the feasibility of this approach. The high-performance liquid chromatographic fingerprint data of historical batches were collected from a traditional Chinese medicine manufacturing factory. Characteristic peaks were weighted by their variability among production batches. A principal component analysis model was established after outliers were modified or removed. Multivariate (Hotelling T(2) and DModX) control charts were finally successfully applied to evaluate the quality consistency. The results suggest useful applications for a combination of multivariate statistical analysis with chromatographic fingerprinting in batch-to-batch quality consistency evaluation for the manufacture of botanical drug products.

Chromatographic Monoliths for High-Throughput Immunoaffinity Isolation of Transferrin from Human Plasma

Directory of Open Access Journals (Sweden)

Irena Trbojević-Akmačić

2016-06-01

Full Text Available Changes in protein glycosylation are related to different diseases and have a potential as diagnostic and prognostic disease biomarkers. Transferrin (Tf glycosylation changes are common marker for congenital disorders of glycosylation. However, biological interindividual variability of Tf N-glycosylation and genes involved in glycosylation regulation are not known. Therefore, high-throughput Tf isolation method and large scale glycosylation studies are needed in order to address these questions. Due to their unique chromatographic properties, the use of chromatographic monoliths enables very fast analysis cycle, thus significantly increasing sample preparation throughput. Here, we are describing characterization of novel immunoaffinity-based monolithic columns in a 96-well plate format for specific high-throughput purification of human Tf from blood plasma. We optimized the isolation and glycan preparation procedure for subsequent ultra performance liquid chromatography (UPLC analysis of Tf N-glycosylation and managed to increase the sensitivity for approximately three times compared to initial experimental conditions, with very good reproducibility. This work is licensed under a Creative Commons Attribution 4.0 International License.

Evaluation and application of a mixed-mode chromatographic stationary phase in two-dimensional liquid chromatography for the separation of traditional Chinese medicine.

Science.gov (United States)

Wei, Zhishen; Fu, Qing; Cai, Jianfeng; Huan, Liyun; Zhao, Jianchao; Shi, Hui; Jin, Yu; Liang, Xinmiao

2016-06-01

In this study, two mixed-mode chromatography stationary phases (C8SAX and C8SCX) were evaluated and used to establish a two-dimensional liquid chromatography system for the separation of traditional Chinese medicine. The chromatographic properties of the mixed-mode columns were systematically evaluated by comparing with other three columns of C8, strong anion exchanger, and strong cation exchanger. The result showed that C8SAX and C8SCX had a mixed-mode retention mechanism including electrostatic interaction and hydrophobic interaction. Especially, they were suitable for separating acidic and/or basic compounds and their separation selectivities could be easily adjusted by changing pH value. Then, several off-line 2D-LC systems based on the C8SAX in the first dimension and C8SAX, C8SCX, or C8 columns in the second dimension were developed to analyze a traditional Chinese medicine-Uncaria rhynchophylla. The two-dimensional liquid chromatography system of C8SAX (pH 3.0) × C8SAX (pH 6.0) exhibited the most effective peak distribution. Finally, fractions of U. rhynchophylla prepared from the first dimension were successfully separated on the C8SAX column with a gradient pH. Thus, the mixed-mode stationary phase could provide a platform to separate the traditional Chinese medicine in practical applications. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Chromatographic hydrogen isotope separation

International Nuclear Information System (INIS)

Aldridge, F.T.

1983-01-01

Intermetallic compounds with the CaCu5 type of crystal structure, particularly LaNiCo and CaNi5, exhibit high separation factors and fast equilibrium times and therefore are useful for packing a chromatographic hydrogen isotope separation column. The addition of an inert metal to dilute the hydride improves performance of the column. A large scale multi-stage chromatographic separation process run as a secondary process off a hydrogen feedstream from an industrial plant which uses large volumes of hydrogen can produce large quantities of heavy water at an effective cost for use in heavy water reactors

Chromatographic hydrogen isotope separation

International Nuclear Information System (INIS)

Aldridge, F.T.

1981-01-01

Intermetallic compounds with the CaCu5 type of crystal structure , particularly LaNiCo and CaNi5, exhibit high separation factors and fast equilibrium times and therefore are useful for packing a chromatographic hydrogen isotope separation colum. The addition of an inert metal to dilute the hydride improves performance of the column. A large scale mutli-stage chromatographic separation process run as a secondary process off a hydrogen feedstream from an industrial plant which uses large volumes of hydrogen can produce large quantities of heavy water at an effective cost for use in heavy water reactors

Development and validation of a reversed phase liquid chromatographic method for analysis of oxytetracycline and related impurities.

Science.gov (United States)

Kahsay, Getu; Shraim, Fairouz; Villatte, Philippe; Rotger, Jacques; Cassus-Coussère, Céline; Van Schepdael, Ann; Hoogmartens, Jos; Adams, Erwin

2013-03-05

A simple, robust and fast high-performance liquid chromatographic method is described for the analysis of oxytetracycline and its related impurities. The principal peak and impurities are all baseline separated in 20 min using an Inertsil C₈ (150 mm × 4.6 mm, 5 μm) column kept at 50 °C. The mobile phase consists of a gradient mixture of mobile phases A (0.05% trifluoroacetic acid in water) and B (acetonitrile-methanol-tetrahydrofuran, 80:15:5, v/v/v) pumped at a flow rate of 1.3 ml/min. UV detection was performed at 254 nm. The developed method was validated for its robustness, sensitivity, precision and linearity in the range from limit of quantification (LOQ) to 120%. The limits of detection (LOD) and LOQ were found to be 0.08 μg/ml and 0.32 μg/ml, respectively. This method allows the separation of oxytetracycline from all known and 5 unknown impurities, which is better than previously reported in the literature. Moreover, the simple mobile phase composition devoid of non-volatile buffers made the method suitable to interface with mass spectrometry for further characterization of unknown impurities. The developed method has been applied for determination of related substances in oxytetracycline bulk samples available from four manufacturers. The validation results demonstrate that the method is reliable for quantification of oxytetracycline and its impurities. Copyright © 2012 Elsevier B.V. All rights reserved.

Identification and quantification of flavonoids in human urine samples by column switching liquid chromatography coupled to atmospheric pressure chemical ionization mass spectrometry

DEFF Research Database (Denmark)

Nielsen, S. E.; Freese, R.; Cornett, Claus

2000-01-01

A rapid and sensitive high-performance liquid chromatographic mass spectrometric (HPLC-MS) method is described for the determination and quantification of 12 dietary flavonoid glycosides and aglycons in human urine samples. Chromatographic separation of the analytes of interest was achieved...... by column-switching, using the first column (a Zorbax 300SB C-3 column) for sample cleanup and eluting the heart-cut flavonoid fraction onto the second column (a Zorbax SE C-18 column) for separation and detection by ultraviolet and atmospheric pressure chemical ionization MS using single ion monitoring...... of variation for the analysis of the 12 different flavonoids in quality control urine samples were 12.3% on average (range 11.0-13.7%, n = 24, reproducibility) and the repeatability of the assay were 5.0% (mean, range 0.1-14.8%, it = 12). A subset of 10 urine samples from a human dietary intervention study...

Resolution of RNA using high-performance liquid chromatography

NARCIS (Netherlands)

Mclaughlin, L.W.; Bischoff, Rainer

1987-01-01

High-performance liquid chromatographic techniques can be very effective for the resolution and isolation of nucleic acids. The characteristic ionic (phosphodiesters) and hydrophobic (nucleobases) properties of RNAs can be exploited for their separation. In this respect anion-exchange and

Chromatographic assay of degradation products of tributyl phosphate

International Nuclear Information System (INIS)

Tripathi, S.C.; Ramanujam, A.; Nadkarni, M.N.; Rao, K.A.; Bandyopadhyay, C.

1985-01-01

Gas-liquid chromatography (GLC) and thin-layer chromatographic (TLC) procedures have been developed for the estimation of monobutyl phosphoric acid (H 2 MBP) and dibutyl phosphoric acid (HDBP) present in tributyl phosphate (TBP). Less than one microgram of H 2 MBP and HDBP is visually detected on TLC plate made of silicagel-cellulose (1:1). HDBP as separated by TLC has been quantitatively estimated in the range of 40-260 μg using an indirect spectrophotometric method. GLC method using 10 percent (W/W) XE-60 column can be effectively used for the simultaneous determination of 0.25 percent W/V H 2 MBP and HDBP present in 30 percent TBP-n-dodecane. The sensitivity may be enhanced 100 fold by careful column conditioning and judicious control of operational parameters. (author)

Optimization of the gas chromatographic separations

International Nuclear Information System (INIS)

Gasco Sanchez, L.

1973-01-01

A review and a critical study on the optimization of the gas chromatographic separations are made. After dealing with the fundamental gas chromatographic equations, some methods of expressing column performances are discussed: performance indices, performance parameters, resolution and effective plate number per unit time. This is completed with a comparative study on performances of various types of columns. Moreover, optimization methods for operating chromatographic conditions are extensively dealt with: as resolution optimization, separation time, and normalization techniques for the time of analysis in order to achieve the maximum resolution at constant time. Finally, some others non operating parameters such as: selectivity of stationary phases, column preparation and optimization methods by means of computers are studied. (Author) 68 refs

Application of Ionic Liquids in High Performance Reversed-Phase Chromatography

Directory of Open Access Journals (Sweden)

Wentao Bi

2009-06-01

Full Text Available Ionic liquids, considered “green” chemicals, are widely used in many areas of analytical chemistry due to their unique properties. Recently, ionic liquids have been used as a kind of novel additive in separation and combined with silica to synthesize new stationary phase as separation media. This review will focus on the properties and mechanisms of ionic liquids and their potential applications as mobile phase modifier and surface-bonded stationary phase in reversed-phase high performance liquid chromatography (RP-HPLC. Ionic liquids demonstrate advantages and potential in chromatographic field.

Rapid Identification of unstable acyl glucoside flavonoids of Oxytropis racemosa Turcz by high-performance liquid chromatography-diode array detection-electrospray ionisation/multi-stage mass spectrometry.

Science.gov (United States)

Song, Shuang; Zheng, Xiu-Ping; Liu, Wei-Dong; Du, Rui-Fang; Feng, Zi-Ming; Zhang, Pei-Cheng; Bi, Li-Fu

2013-02-01

Oxytropis racemosa Turcz is an important minority medicine that is used mainly to improve children's indigestion, especially in inner Mongolia and Tibet. Previous studies indicated that the characteristic constituents of this plant are acylated flavonoids. Rapidly identify the characteristic chemical constituents of O. racemosa by high-performance liquid chromatography-diode array detection-electrospray ionisation/multi-stage mass spectrometry (HPLC-DAD-ESI/MS(n) ) and suggest a useful method to control the quality of this medicinal plant. In the HPLC fingerprint, 32 flavonoids were tentatively identified by a detailed analysis of their mass spectra, UV spectra and retention times. Furthermore, 13 flavonoids were confirmed by comparison with previously isolated compounds obtained from O. racemosa. In total, 32 flavonoids, including 13 flavonoids with 3-hydroxy-3-methylglutaric acid (HMG) moieties and four flavonoids with 3-malonyl moieties, were identified in the extract of O. racemosa. Among the compounds identified, 10 were characterised as new compounds for their particular acylated sugar moieties. The method described is effective for obtaining a comprehensive phytochemical profile of plants containing unstable acylated flavonoids. The method is also useful for constructing the chromatographic fingerprint of the minority medicine -O. racemosa Turcz for quality control. Copyright © 2012 John Wiley & Sons, Ltd.

A Rapid Determination of Cinnarizine in Bulk and Pharmaceutical Dosage Form by LC

Directory of Open Access Journals (Sweden)

A. A. Heda

2010-01-01

Full Text Available A simple, selective, rapid and precise reverse phase high pressure liquid chromatographic method has been developed for the estimation of cinnarizine from pharmaceutical formulation. The method was developed using MICRA-NPS C18 (length×OD×ID =33×8.0×6.0 mm, 1.5 μm column with a mobile phase consisting of acetonitrile, triethylamine buffer (adjusted to pH 4.5 with 10% w/v potassium hydroxide and tetrahydrofuran in the ratio 30:66:4 respectively, at a flow rate of 0.5 mL/min. Wavelength was fixed at 253 nm. The developed method was validated for linearity, accuracy, precision, limit of detection and limit of quantitation. The proposed method can be used for the routine estimation of cinnarizine in pharmaceutical dosage form.

A Small-Scale Low-Cost Gas Chromatograph

Science.gov (United States)

Gros, Natasa; Vrtacnik, Margareta

2005-01-01

The design and application of a small-scale portable gas chromatograph for learning of the basic concepts of chromatography is described. The apparatus consists of two basic separable units, which includes a chromatographic unit and an electronic unit.

Rapid Analysis Procedures for Triglycerides and Fatty Acids as Pentyl and Phenethyl Esters for the Detection of Butter Adulteration Using Chromatographic Techniques

Directory of Open Access Journals (Sweden)

Daniele Naviglio

2017-01-01

Full Text Available This paper presents the development of three methods for quality control, fraud detection, and authentication of butter fat and other oils/fats using chromatographic techniques, with one method for triglycerides and two methods for fatty acids (FAs. The procedure for the analysis of triglycerides requires only dissolution of the sample in n-hexane and gas chromatography (GC analysis using a capillary column. The second method is based on the transesterification of triglycerides as pentyl esters in a single-step reaction using sodium pentanoate in pentanol. The reaction proceeds at room temperature and is similar to the potassium hydroxide-catalysed transesterification of triglycerides with methanol and even more similar to the sodium methoxide method and sodium butanoate method. The advantage of using pentyl esters includes reducing the volatility of short-chain FAs, and substantial recoveries were obtained compared with methyl ester analysis. The third method involves the transesterification of triglycerides in fat through reaction with 2-phenylethanol in a single step; 2-phenylethanol possesses a chromophore, and the phenethyl esters formed are analysed by high-performance liquid chromatography (HPLC with UV detection.

Application of an efficient strategy based on liquid-liquid extraction, high-speed counter-current chromatography, and preparative HPLC for the rapid enrichment, separation, and purification of four anthraquinones from Rheum tanguticum.

Science.gov (United States)

Chen, Tao; Liu, Yongling; Zou, Denglang; Chen, Chen; You, Jinmao; Zhou, Guoying; Sun, Jing; Li, Yulin

2014-01-01

This study presents an efficient strategy based on liquid-liquid extraction, high-speed counter-current chromatography, and preparative HPLC for the rapid enrichment, separation, and purification of four anthraquinones from Rheum tanguticum. A new solvent system composed of petroleum ether/ethyl acetate/water (4:2:1, v/v/v) was developed for the liquid-liquid extraction of the crude extract from R. tanguticum. As a result, emodin, aloe-emodin, physcion, and chrysophanol were greatly enriched in the organic layer. In addition, an efficient method was successfully established to separate and purify the above anthraquinones by high-speed counter-current chromatography and preparative HPLC. This study supplies a new alternative method for the rapid enrichment, separation, and purification of emodin, aloe-emodin, physcione, and chrysophanol. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Chromatographic determination of the rate and extent of absorption of air pollutants by sea water

International Nuclear Information System (INIS)

Nikolakaki, S.; Vassilakos, C.; Katsanos, N.A.

1994-01-01

A simple chromatographic method is developed to determine the rate constant for expulsion of an air pollutant from water or its diffusion parameter in the liquid, the rate constant for chemical reaction of the pollutant with water, its mass transfer coefficient in the liquid, and the partition coefficient between liquid water and air. From these physicochemical parameters, the absorption rate by sea water and, therefore, the depletion rate of a polluting substance from the air can be calculated, together with the equilibrium state of this absorption. The method has been applied to nitrogen dioxide being absorbed by triple-distilled water and by sea water, at various temperatures. From the temperature variation of the reaction rate constant and of the partition coefficient, the activation energy for the reaction and the differential heat of solution were determined. (orig.)

Determination of Ignitable Liquids in Fire Debris: Direct Analysis by Electronic Nose

Directory of Open Access Journals (Sweden)

Marta Ferreiro-González

2016-05-01

Full Text Available Arsonists usually use an accelerant in order to start or accelerate a fire. The most widely used analytical method to determine the presence of such accelerants consists of a pre-concentration step of the ignitable liquid residues followed by chromatographic analysis. A rapid analytical method based on headspace-mass spectrometry electronic nose (E-Nose has been developed for the analysis of Ignitable Liquid Residues (ILRs. The working conditions for the E-Nose analytical procedure were optimized by studying different fire debris samples. The optimized experimental variables were related to headspace generation, specifically, incubation temperature and incubation time. The optimal conditions were 115 °C and 10 min for these two parameters. Chemometric tools such as hierarchical cluster analysis (HCA and linear discriminant analysis (LDA were applied to the MS data (45–200 m/z to establish the most suitable spectroscopic signals for the discrimination of several ignitable liquids. The optimized method was applied to a set of fire debris samples. In order to simulate post-burn samples several ignitable liquids (gasoline, diesel, citronella, kerosene, paraffin were used to ignite different substrates (wood, cotton, cork, paper and paperboard. A full discrimination was obtained on using discriminant analysis. This method reported here can be considered as a green technique for fire debris analyses.

Determination of Ignitable Liquids in Fire Debris: Direct Analysis by Electronic Nose

Science.gov (United States)

Ferreiro-González, Marta; Barbero, Gerardo F.; Palma, Miguel; Ayuso, Jesús; Álvarez, José A.; Barroso, Carmelo G.

2016-01-01

Arsonists usually use an accelerant in order to start or accelerate a fire. The most widely used analytical method to determine the presence of such accelerants consists of a pre-concentration step of the ignitable liquid residues followed by chromatographic analysis. A rapid analytical method based on headspace-mass spectrometry electronic nose (E-Nose) has been developed for the analysis of Ignitable Liquid Residues (ILRs). The working conditions for the E-Nose analytical procedure were optimized by studying different fire debris samples. The optimized experimental variables were related to headspace generation, specifically, incubation temperature and incubation time. The optimal conditions were 115 °C and 10 min for these two parameters. Chemometric tools such as hierarchical cluster analysis (HCA) and linear discriminant analysis (LDA) were applied to the MS data (45–200 m/z) to establish the most suitable spectroscopic signals for the discrimination of several ignitable liquids. The optimized method was applied to a set of fire debris samples. In order to simulate post-burn samples several ignitable liquids (gasoline, diesel, citronella, kerosene, paraffin) were used to ignite different substrates (wood, cotton, cork, paper and paperboard). A full discrimination was obtained on using discriminant analysis. This method reported here can be considered as a green technique for fire debris analyses. PMID:27187407

Chromatographic fingerprint analysis of yohimbe bark and related dietary supplements using UHPLC/UV/MS.

Science.gov (United States)

Sun, Jianghao; Chen, Pei

2012-03-05

A practical ultra high-performance liquid chromatography (UHPLC) method was developed for fingerprint analysis of and determination of yohimbine in yohimbe barks and related dietary supplements. Good separation was achieved using a Waters Acquity BEH C(18) column with gradient elution using 0.1% (v/v) aqueous ammonium hydroxide and 0.1% ammonium hydroxide in methanol as the mobile phases. The study is the first reported chromatographic method that separates corynanthine from yohimbine in yohimbe bark extract. The chromatographic fingerprint analysis was applied to the analysis of 18 yohimbe commercial dietary supplement samples. Quantitation of yohimbine, the traditional method for analysis of yohimbe barks, were also performed to evaluate the results of the fingerprint analysis. Wide variability was observed in fingerprints and yohimbine content among yohimbe dietary supplement samples. For most of the dietary supplements, the yohimbine content was not consistent with the label claims. Copyright © 2011. Published by Elsevier B.V.

Chromatographic Determination of Toluene and its Metabolites in Urine for Toluene Exposure - A Review

International Nuclear Information System (INIS)

Mohamad Raizul Zinalibdin; Abdul Rahim Yacob; Mohd Marsin Sanagi

2016-01-01

The determinations of toluene and their metabolites in biological samples such as urine and blood allow the estimation of the degree of exposure to this chemical. Chromatographic methods and preliminary methods are now universally employed for this purpose. Preliminary color test methods are well established for qualitative determination of toluene and its metabolites. Mobile test kits using color test methods are a vast tool for screening urine samples but chromatographic methods are still needed for confirmation and quantitative analysis. Gas chromatography (GC) methods are well-adapted for the determination of toluene metabolite in urine, but these methods often require several pretreatment steps. Meanwhile, high performance liquid chromatography (HPLC) is becoming a powerful tool for the accurate and easy determination of toluene metabolites considering its decisive advantages for routine monitoring. Furthermore, recent development in HPLC could widen the usefulness of this method to solve the most complex analytical problems that could be encountered during the measurement. (author)

Analysis of Poly-β-Hydroxybutyrate in Rhizobium japonicum Bacteroids by Ion-Exclusion High-Pressure Liquid Chromatography and UV Detection †

Science.gov (United States)

Karr, Dale B.; Waters, James K.; Emerich, David W.

1983-01-01

Ion-exclusion high-pressure liquid chromatography (HPLC) was used to measure poly-β-hydroxybutyrate (PHB) in Rhizobium japonicum bacteroids. The products in the acid digest of PHB-containing material were fractionated by HPLC on Aminex HPX-87H ion-exclusion resin for organic acid analysis. Crotonic acid formed from PHB during acid digestion was detected by its intense absorbance at 210 nm. The Aminex-HPLC method provides a rapid and simple chromatographic technique for routine analysis of organic acids. Results of PHB analysis by Aminex-HPLC were confirmed by gas chromatography and spectrophotometric analysis. PMID:16346443

New chromatographic method for separating Omeprazole from its degradation components and the quantitatively determining it in its pharmaceutical products

International Nuclear Information System (INIS)

Touma, M.; Rajab, A.; Seuleiman, M.

2007-01-01

New chromatographic method for Quantitative Determination of Omeprazole in its Pharmaceutical Products was produced. Omeprazole and its degradation components were well separated in same chromatogram by using high perfume liquid chromatography (HPLC). The new analytical method has been validated by these characteristic tests (accuracy, precision, range, linearity, specificity/selectivity, limit of detection (LOD) and limit of quantitative (LOQ) ).(author)

New chromatographic Methods for Separation of Lansoprazole from its Degradation Components and The Quantitative Determination in its Pharmaceutical Products

International Nuclear Information System (INIS)

Touma, M.; Rajab, A.

2009-01-01

New chromatographic method was found for Quantitative Determination of Lansoprazole in its pharmaceutical products. Lansoprazole and its degradation components were well separated in same chromatogram by using high perfume liquid chromatography (HPLC). The new analytical method has been validated by these characteristic tests (accuracy, precision, range, linearity, specificity/selectivity, limit of detection (LOD) and limit of quantitative (LOQ)). (author)

[Research on the application of grey system theory in the pattern recognition for chromatographic fingerprints of traditional Chinese medicine].

Science.gov (United States)

Wei, Hang; Lin, Li; Zhang, Yuan; Wang, Lianjing; Chen, Qinqun

2013-02-01

A model based on grey system theory was proposed for pattern recognition in chromatographic fingerprints (CF) of traditional Chinese medicine (TCM). The grey relational grade among the data series of each testing CF and the ideal CF was obtained by entropy and norm respectively, then the principle of "maximal matching degree" was introduced to make judgments, so as to achieve the purpose of variety identification and quality evaluation. A satisfactory result in the high performance liquid chromatographic (HPLC) analysis of 56 batches of different varieties of Exocarpium Citrus Grandis was achieved with this model. The errors in the chromatographic fingerprint analysis caused by traditional similarity method or grey correlation method were overcome, as the samples of Citrus grandis 'Tomentosa' and Citrus grandis (L.) Osbeck were correctly distinguished in the experiment. Furthermore in the study on the variety identification of Citrus grandis 'Tomentosa', the recognition rates were up to 92.85%, although the types and the contents of the chemical compositions of the samples were very close. At the same time, the model had the merits of low computation complexity and easy operation by computer programming. The research indicated that the grey system theory has good applicability to pattern recognition in the chromatographic fingerprints of TCM.

Use of liquid chromatography for measuring atmospheric sulfur dioxide and nitrogen oxide

Energy Technology Data Exchange (ETDEWEB)

Benova, E

1973-02-01

A literature search to ascertain the applicability of liquid chromatography to the analysis of atmospheric sulfur dioxide and various oxides of nitrogen is reported. Simple or enriched samples can be analyzed. Plastic bags are recommended for preparation of simple samples; and a table of 18 plastic materials, their manufacturers, and pollutants to which they are inert is provided. Enriched samples can be prepared in chromatographic columns by adsorption methods. Tables are provided listing carriers, stationary phase materials, temperatures, carrier liquids (helium or nitrogen), column dimensions, and other data recommended for chromatographic tests of SO/sub 2/ and NOx. Because of its reactivity and tendency to polymerize, sulfur trioxide should be reduced to SO/sub 2/ prior to analysis.

Single-column extraction chromatographic separation of U, Pu, Np and Am

Energy Technology Data Exchange (ETDEWEB)

Morgenstern, A.; Apostolidis, C.; Carlos-Marquez, R.; Mayer, K.; Molinet, R. [Commission of the European Communities, Karlsruhe (Germany). European Inst. for Transuranium Elements

2002-07-01

A rapid, single-column extraction chromatographic method using commercially available UTEVA resin has been developed for the separation of uranium, plutonium, neptunium and americium. The method yields recoveries superior to 90% and allows direct loading of separated fractions on filaments for subsequent analysis by thermal ionization mass spectrometry. The use of reagents compatible with robotized equipment allows automation of the separation process for routine analysis of nuclear materials. The redox reactions between plutonium, neptunium and hydrogen peroxide involved in the separation process were studied by UV/Vis/NIR absorption spectroscopy. (orig.)

Sample preparation for liquid chromatographic analysis of phytochemicals in biological fluids.

Science.gov (United States)

Oh, Ju-Hee; Lee, Young-Joo

2014-01-01

Natural products have been used traditionally for the treatment and prevention of diseases for thousands of years and are nowadays consumed as dietary supplements and herbal medicine. To ensure the safe and effective use of these herbal products, information about bioavailability of active compounds in plasma or target tissues should be provided via validated analytical methods combined with appropriate sampling methods. To provide comprehensive and abridged information about sample preparation methods for the quantification of phytochemicals in biological samples using liquid chromatography analysis. Sample pre-treatment procedures used in analytical methods for in vivo pharmacokinetic studies of natural compounds or herbal medicines were reviewed. These were categorised according to the biological matrices (plasma, bile, urine, faeces and tissues) and sample clean-up processes (protein precipitation, liquid-liquid extraction and solid-phase extraction). Although various kinds of sample pre-treatment methods have been developed, liquid-liquid extraction is still widely used and solid-phase extraction is becoming increasingly popular because of its efficiency for extensive clean up of complex matrix samples. However, protein precipitation is still favoured due to its simplicity. Sample treatment for phytochemical analysis in biological fluids is an indispensable and critical step to obtain high quality results. This step could dominate the overall analytical process because both the duration of the process as well as the reliability of the data depend in large part on its efficiency. Thus, special attention should be given to the choice of a proper sample treatment method that targets analytes and their biomatrix. Copyright © 2013 John Wiley & Sons, Ltd.

[Advances of poly (ionic liquid) materials in separation science].

Science.gov (United States)

Liu, Cuicui; Guo, Ting; Su, Rina; Gu, Yuchen; Deng, Qiliang

2015-11-01

Ionic liquids, as novel ionization reagents, possess beneficial characteristics including good solubility, conductivity, thermal stability, biocompatibility, low volatility and non-flammability. Ionic liquids are attracting a mass of attention of analytical chemists. Poly (ionic liquid) materials have common performances of ionic liquids and polymers, and have been successfully applied in separation science area. In this paper, we discuss the interaction mechanisms between the poly(ionic liquid) materials and analytes including hydrophobic/hydrophilic interactions, hydrogen bond, ion exchange, π-π stacking and electrostatic interactions, and summarize the application advances of the poly(ionic liquid) materials in solid phase extraction, chromatographic separation and capillary electrophoresis. At last, we describe the future prospect of poly(ionic liquid) materials.

Rapid determination of triclosan in personal care products using new in-tube based ultrasound-assisted salt-induced liquid-liquid microextraction coupled with high performance liquid chromatography-ultraviolet detection.

Science.gov (United States)

Chen, Ming-Jen; Liu, Ya-Ting; Lin, Chiao-Wen; Ponnusamy, Vinoth Kumar; Jen, Jen-Fon

2013-03-12

This paper describes the development of a novel, simple and efficient in-tube based ultrasound-assisted salt-induced liquid-liquid microextraction (IT-USA-SI-LLME) technique for the rapid determination of triclosan (TCS) in personal care products by high performance liquid chromatography-ultraviolet (HPLC-UV) detection. IT-USA-SI-LLME method is based on the rapid phase separation of water-miscible organic solvent from the aqueous phase in the presence of high concentration of salt (salting-out phenomena) under ultrasonication. In the present work, an indigenously fabricated home-made glass extraction device (8-mL glass tube inbuilt with a self-scaled capillary tip) was utilized as the phase separation device for USA-SI-LLME. After the extraction, the upper extractant layer was narrowed into the self-scaled capillary tip by pushing the plunger plug; thus, the collection and measurement of the upper organic solvent layer was simple and convenient. The effects of various parameters on the extraction efficiency were thoroughly evaluated and optimized. Under optimal conditions, detection was linear in the concentration range of 0.4-100ngmL(-1) with correlation coefficient of 0.9968. The limit of detection was 0.09ngmL(-1) and the relative standard deviations ranged between 0.8 and 5.3% (n=5). The applicability of the developed method was demonstrated for the analysis of TCS in different commercial personal care products and the relative recoveries ranged from 90.4 to 98.5%. The present method was proven to be a simple, sensitive, less organic solvent consuming, inexpensive and rapid procedure for analysis of TCS in a variety of commercially available personal care products or cosmetic preparations. Copyright © 2013 Elsevier B.V. All rights reserved.

Sample preparation for large-scale bioanalytical studies based on liquid chromatographic techniques.

Science.gov (United States)

Medvedovici, Andrei; Bacalum, Elena; David, Victor

2018-01-01

Quality of the analytical data obtained for large-scale and long term bioanalytical studies based on liquid chromatography depends on a number of experimental factors including the choice of sample preparation method. This review discusses this tedious part of bioanalytical studies, applied to large-scale samples and using liquid chromatography coupled with different detector types as core analytical technique. The main sample preparation methods included in this paper are protein precipitation, liquid-liquid extraction, solid-phase extraction, derivatization and their versions. They are discussed by analytical performances, fields of applications, advantages and disadvantages. The cited literature covers mainly the analytical achievements during the last decade, although several previous papers became more valuable in time and they are included in this review. Copyright © 2017 John Wiley & Sons, Ltd.

Probabilistic peak detection for first-order chromatographic data.

Science.gov (United States)

Lopatka, M; Vivó-Truyols, G; Sjerps, M J

2014-03-19

We present a novel algorithm for probabilistic peak detection in first-order chromatographic data. Unlike conventional methods that deliver a binary answer pertaining to the expected presence or absence of a chromatographic peak, our method calculates the probability of a point being affected by such a peak. The algorithm makes use of chromatographic information (i.e. the expected width of a single peak and the standard deviation of baseline noise). As prior information of the existence of a peak in a chromatographic run, we make use of the statistical overlap theory. We formulate an exhaustive set of mutually exclusive hypotheses concerning presence or absence of different peak configurations. These models are evaluated by fitting a segment of chromatographic data by least-squares. The evaluation of these competing hypotheses can be performed as a Bayesian inferential task. We outline the potential advantages of adopting this approach for peak detection and provide several examples of both improved performance and increased flexibility afforded by our approach. Copyright © 2014 Elsevier B.V. All rights reserved.

Incorporating high-pressure electroosmotic pump and a nano-flow gradient generator into a miniaturized liquid chromatographic system for peptide analysis.

Science.gov (United States)

Chen, Apeng; Lynch, Kyle B; Wang, Xiaochun; Lu, Joann J; Gu, Congying; Liu, Shaorong

2014-09-24

We integrate a high-pressure electroosmotic pump (EOP), a nanoflow gradient generator, and a capillary column into a miniaturized liquid chromatographic system that can be directly coupled with a mass spectrometer for proteomic analysis. We have recently developed a low-cost high-pressure EOP capable of generating pressure of tens of thousands psi, ideal for uses in miniaturized HPLC. The pump worked smoothly when it was used for isocratic elutions. When it was used for gradient elutions, generating reproducible gradient profiles was challenging; because the pump rate fluctuated when the pump was used to pump high-content organic solvents. This presents an issue for separating proteins/peptides since high-content organic solvents are often utilized. In this work, we solve this problem by incorporating our high-pressure EOP with a nano-flow gradient generator so that the EOP needs only to pump an aqueous solution. With this combination, we develop a capillary-based nano-HPLC system capable of performing nano-flow gradient elution; the pump rate is stable, and the gradient profiles are reproducible and can be conveniently tuned. To demonstrate its utility, we couple it with either a UV absorbance detector or a mass spectrometer for peptide separations. Copyright © 2014. Published by Elsevier B.V.

Further Validation of a Rapid Screening Semiquantitative Thin-Layer Chromatographic Method for Marketed Antimalarial Medicines for Adoption in Malawi

Directory of Open Access Journals (Sweden)

Dorcas Osei-Safo

2018-01-01

Full Text Available A recently developed semiquantitative thin-layer chromatographic (SQ-TLC assay has been employed in postmarketing surveillance of antimalarial medicines used in Malawi prior to HPLC assay. Both methods gave analogous results in a significant majority of the samples, with a good correlation (r = 0.9012 for the active pharmaceutical ingredients of the dosage forms assayed. Artemether-containing medicines had the highest percentage (92.67% of samples with comparable results for both assays. The lowest percentage (66.67% was observed in artesunate-containing medicines. The SQ-TLC method was validated for specificity, accuracy, precision, linearity, and stability according to the International Conference on Harmonisation guidelines, with the results falling within acceptable limits. For specificity, retention factor values of the test samples and reference standards were comparable, while accuracy and precision of 91.1 ± 5.7% were obtained for all samples. The method was linear in the range 1.0–2.0 µg/spot with a correlation coefficient of r = 0.9783. Stability tests also fell within acceptable limits. In this study, we present the validation of the SQ-TLC method and propose its adoption as a rapid screening tool for field estimation of the quality of antimalarial and other essential medicines in Malawi and other parts of the developing world prior to a more accurate HPLC assay.

Characterization of organic and conventional sweet basil leaves using chromatographic and flow-injection mass spectrometric (FIMS) fingerprints combined with principal component analysis

Science.gov (United States)

Lu, Yingjian; Gao, Boyan; Chen, Pei; Charles, Denys; Yu, Liangli (Lucy)

2014-01-01

Sweet basil, Ocimum basilicum., is one of the most important and wildly used spices and has been shown to have antioxidant, antibacterial, and anti-diarrheal activities. In this study, high performance liquid chromatographic (HPLC) and flow-injection mass spectrometric (FIMS) fingerprinting techniques were used to differentiate organic and conventional sweet basil leaf samples. Principal component analysis (PCA) of the fingerprints indicated that both HPLC and FIMS fingerprints could effectively detect the chemical differences in the organic and conventional sweet basil leaf samples. This study suggested that the organic basil sample contained greater concentrations of almost all the major compounds than its conventional counterpart on a per same botanical weight basis. The FIMS method was able to rapidly differentiate the organic and conventional sweet basil leaf samples (1 min analysis time), whereas the HPLC fingerprints provided more information about the chemical composition of the basil samples with a longer analytical time. PMID:24518341

3D printed titanium micro-bore columns containing polymer monoliths for reversed-phase liquid chromatography.

Science.gov (United States)

Gupta, Vipul; Talebi, Mohammad; Deverell, Jeremy; Sandron, Sara; Nesterenko, Pavel N; Heery, Brendan; Thompson, Fletcher; Beirne, Stephen; Wallace, Gordon G; Paull, Brett

2016-03-03

The potential of 3D selective laser melting (SLM) technology to produce compact, temperature and pressure stable titanium alloy chromatographic columns is explored. A micro bore channel (0.9 mm I.D. × 600 mm long) was produced within a 5 × 30 × 30 mm titanium alloy (Ti-6Al-4V) cuboid, in form of a double handed spiral. A poly(butyl methacrylate-co-ethyleneglycoldimethacrylate) (BuMA-co-EDMA) monolithic stationary phase was thermally polymerised within the channel for application in reversed-phase high-performance liquid chromatography. The prepared monolithic column was applied to the liquid chromatographic separation of intact proteins and peptides. Peak capacities of 69-76 (for 6-8 proteins respectively) were observed during isothermal separation of proteins at 44 °C which were further increased to 73-77 using a thermal step gradient with programmed temperature from 60 °C to 35 °C using an in-house built direct-contact heater/cooler platform based upon matching sized Peltier thermoelectric modules. Rapid temperature gradients were possible due to direct-contact between the planar metal column and the Peltier module, and the high thermal conductivity of the titanium column as compared to a similar stainless steel printed column. The separation of peptides released from a digestion of E.coli was also achieved in less than 35 min with ca. 40 distinguishable peaks at 210 nm. Copyright © 2016 Elsevier B.V. All rights reserved.

Rapid hydrogen hydrate growth from non-stoichiometric tuning mixtures during liquid nitrogen quenching.

Science.gov (United States)

Grim, R Gary; Kerkar, Prasad B; Sloan, E Dendy; Koh, Carolyn A; Sum, Amadeu K

2012-06-21

In this study the rapid growth of sII H(2) hydrate within 20 min of post formation quenching towards liquid nitrogen (LN(2)) temperature is presented. Initially at 72 MPa and 258 K, hydrate samples would cool to the conditions of ~60 MPa and ~90 K after quenching. Although within the stability region for H(2) hydrate, new hydrate growth only occurred under LN(2) quenching of the samples when preformed hydrate "seeds" of THF + H(2) were in the presence of unconverted ice. The characterization of hydrate seeds and the post-quenched samples was performed with confocal Raman spectroscopy. These results suggest that quenching to LN(2) temperature, a common preservation technique for ex situ hydrate analysis, can lead to rapid unintended hydrate growth. Specifically, guest such as H(2) that may otherwise need sufficiently long induction periods to nucleate, may still experience rapid growth through an increased kinetic effect from a preformed hydrate template.

Liquid chromatography with luminol-based electrochemiluminescence detection determination of histamine

NARCIS (Netherlands)

Steijger, O.M.; Kamminga, D.A.; Brummelhuis, A.; Lingeman, H.

1998-01-01

The liquid chromatographic determination of histamine was achieved by precolumn derivatization with N-(4-aminobutyl)-N-ethylisoluminol isothiocyanate and electrochemiluminescence detection. Detection was carried out using postcolumn on-line electrochemical reagent generation and oxidation of the

On the use of ionic liquids as mobile phase additives in high-performance liquid chromatography. A review.

Science.gov (United States)

García-Alvarez-Coque, M C; Ruiz-Angel, M J; Berthod, A; Carda-Broch, S

2015-07-09

The popularity of ionic liquids (ILs) has grown during the last decades in several analytical separation techniques. Consequently, the number of reports devoted to the applications of ILs is still increasing. This review is focused on the use of ILs (mainly imidazolium-based associated to chloride and tetrafluoroborate) as mobile phase additives in high-performance liquid chromatography (HPLC). In this approach, ILs just function as salts, but keep several kinds of intermolecular interactions, which are useful for chromatographic separations. Both cation and anion can be adsorbed on the stationary phase, creating a bilayer. This gives rise to hydrophobic, electrostatic and other specific interactions with the stationary phase and solutes, which modify the retention behaviour and peak shape. This review updates the advances in this field, with emphasis on topics not always deeply considered in the literature, such as the mechanisms of retention, the estimation of the suppressing potency of silanols, modelling and optimisation of the chromatographic performance, and the comparison with other additives traditionally used to avoid the silanol problem. Copyright © 2015 Elsevier B.V. All rights reserved.

Chromatographic Techniques for Rare Earth Elements Analysis

Science.gov (United States)

Chen, Beibei; He, Man; Zhang, Huashan; Jiang, Zucheng; Hu, Bin

2017-04-01

The present capability of rare earth element (REE) analysis has been achieved by the development of two instrumental techniques. The efficiency of spectroscopic methods was extraordinarily improved for the detection and determination of REE traces in various materials. On the other hand, the determination of REEs very often depends on the preconcentration and separation of REEs, and chromatographic techniques are very powerful tools for the separation of REEs. By coupling with sensitive detectors, many ambitious analytical tasks can be fulfilled. Liquid chromatography is the most widely used technique. Different combinations of stationary phases and mobile phases could be used in ion exchange chromatography, ion chromatography, ion-pair reverse-phase chromatography and some other techniques. The application of gas chromatography is limited because only volatile compounds of REEs can be separated. Thin-layer and paper chromatography are techniques that cannot be directly coupled with suitable detectors, which limit their applications. For special demands, separations can be performed by capillary electrophoresis, which has very high separation efficiency.

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.

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 ...

Use of refractometry and colorimetry as field methods to rapidly assess antimalarial drug quality.

Science.gov (United States)

Green, Michael D; Nettey, Henry; Villalva Rojas, Ofelia; Pamanivong, Chansapha; Khounsaknalath, Lamphet; Grande Ortiz, Miguel; Newton, Paul N; Fernández, Facundo M; Vongsack, Latsamy; Manolin, Ot

2007-01-04

The proliferation of counterfeit and poor-quality drugs is a major public health problem; especially in developing countries lacking adequate resources to effectively monitor their prevalence. Simple and affordable field methods provide a practical means of rapidly monitoring drug quality in circumstances where more advanced techniques are not available. Therefore, we have evaluated refractometry, colorimetry and a technique combining both processes as simple and accurate field assays to rapidly test the quality of the commonly available antimalarial drugs; artesunate, chloroquine, quinine, and sulfadoxine. Method bias, sensitivity, specificity and accuracy relative to high-performance liquid chromatographic (HPLC) analysis of drugs collected in the Lao PDR were assessed for each technique. The HPLC method for each drug was evaluated in terms of assay variability and accuracy. The accuracy of the combined method ranged from 0.96 to 1.00 for artesunate tablets, chloroquine injectables, quinine capsules, and sulfadoxine tablets while the accuracy was 0.78 for enterically coated chloroquine tablets. These techniques provide a generally accurate, yet simple and affordable means to assess drug quality in resource-poor settings.

Determination of marker pteridins and biopterin reduced forms, tetrahydrobiopterin and dihydrobiopterin, in human urine, using a post-column photoinduced fluorescence liquid chromatographic derivatization method

International Nuclear Information System (INIS)

Canada-Canada, Florentina; Espinosa-Mansilla, Anunciacion; Munoz de la Pena, Arsenio; Mancha de Llanos, Alicia

2009-01-01

A liquid chromatographic method for the simultaneous analysis of marker pteridins and biopterin reduced forms, in urine samples is proposed. A Zorbax Eclipse XDB-C18 column was used for the chromatographic separation, using a 98/2 (v/v), citrate buffer (pH 5.5)-acetonitrile mobile phase, in isocratic mode. A post-column photoderivatization was carried out with an on-line photoreactor, located between a diode array detector (DAD) and a fast scanning fluorescence detector (FSFD). Neopterin (NEO), biopterin (BIO), pterin (PT) and dihydrobiopterin (BH2) were determined by measuring native fluorescence, using the photoreactor in OFF-mode, and tetrahydrobiopterin (BH4) was determined by measuring of the induced fluorescence of the generated photoproducts, using the photoreactor in ON-mode. In addition, Creatinine (CREA), as a reference of metabolites excrection in urine, was simultaneously determined using the DAD detector. Detection limits were 0.2, 13.0, 0.3, 0.3 and 3.5 ng mL -1 , for NEO, BH2, BIO, PT and BH4, respectively, and 0.4 μg mL -1 for CREA. Ratio values for NEO/CREA, PT/CREA, BH4/CREA, BH2/CREA, NEO/BIO and BIO total /CREA, in urine samples, of healthy children and adults, phenylketonuric children and infected mononucleosis children, are reported. A comparative study, about the mean values obtained for each of the compounds, by the present procedure and by the classical iodine oxidation method (Fukushimas method), has been performed, in urine samples belonging to healthy volunteers. The values obtained were BH4/CREA: 0.41, BH2/CREA: 0.31 and BIO total /CREA: 0.73, by the proposed method, and BH4/CREA: 0.35, BH2/CREA: 0.20 and BIO total /CREA: 0.48, by iodine oxidation method.

Determination of marker pteridins and biopterin reduced forms, tetrahydrobiopterin and dihydrobiopterin, in human urine, using a post-column photoinduced fluorescence liquid chromatographic derivatization method

Energy Technology Data Exchange (ETDEWEB)

Canada-Canada, Florentina, E-mail: floricanada@gmail.com [Department of Analytical Chemistry, University of Extremadura, 06071 Badajoz (Spain); Espinosa-Mansilla, Anunciacion; Munoz de la Pena, Arsenio; Mancha de Llanos, Alicia [Department of Analytical Chemistry, University of Extremadura, 06071 Badajoz (Spain)

2009-08-19

A liquid chromatographic method for the simultaneous analysis of marker pteridins and biopterin reduced forms, in urine samples is proposed. A Zorbax Eclipse XDB-C18 column was used for the chromatographic separation, using a 98/2 (v/v), citrate buffer (pH 5.5)-acetonitrile mobile phase, in isocratic mode. A post-column photoderivatization was carried out with an on-line photoreactor, located between a diode array detector (DAD) and a fast scanning fluorescence detector (FSFD). Neopterin (NEO), biopterin (BIO), pterin (PT) and dihydrobiopterin (BH2) were determined by measuring native fluorescence, using the photoreactor in OFF-mode, and tetrahydrobiopterin (BH4) was determined by measuring of the induced fluorescence of the generated photoproducts, using the photoreactor in ON-mode. In addition, Creatinine (CREA), as a reference of metabolites excrection in urine, was simultaneously determined using the DAD detector. Detection limits were 0.2, 13.0, 0.3, 0.3 and 3.5 ng mL{sup -1}, for NEO, BH2, BIO, PT and BH4, respectively, and 0.4 {mu}g mL{sup -1} for CREA. Ratio values for NEO/CREA, PT/CREA, BH4/CREA, BH2/CREA, NEO/BIO and BIO{sub total}/CREA, in urine samples, of healthy children and adults, phenylketonuric children and infected mononucleosis children, are reported. A comparative study, about the mean values obtained for each of the compounds, by the present procedure and by the classical iodine oxidation method (Fukushimas method), has been performed, in urine samples belonging to healthy volunteers. The values obtained were BH4/CREA: 0.41, BH2/CREA: 0.31 and BIO{sub total}/CREA: 0.73, by the proposed method, and BH4/CREA: 0.35, BH2/CREA: 0.20 and BIO{sub total}/CREA: 0.48, by iodine oxidation method.

Evaluation of the suitability of chromatographic systems to predict human skin permeation of neutral compounds.

Science.gov (United States)

Hidalgo-Rodríguez, Marta; Soriano-Meseguer, Sara; Fuguet, Elisabet; Ràfols, Clara; Rosés, Martí

2013-12-18

Several chromatographic systems (three systems of high-performance liquid chromatography and two micellar electrokinetic chromatography systems) besides the reference octanol-water partition system are evaluated by a systematic procedure previously proposed in order to know their ability to model human skin permeation. The precision achieved when skin-water permeability coefficients are correlated against chromatographic retention factors is predicted within the framework of the solvation parameter model. It consists in estimating the contribution of error due to the biological and chromatographic data, as well as the error coming from the dissimilarity between the human skin permeation and the chromatographic systems. Both predictions and experimental tests show that all correlations are greatly affected by the considerable uncertainty of the skin permeability data and the error associated to the dissimilarity between the systems. Correlations with much better predictive abilities are achieved when the volume of the solute is used as additional variable, which illustrates the main roles of both lipophilicity and size of the solute to penetrate through the skin. In this way, the considered systems are able to give precise estimations of human skin permeability coefficients. In particular, the HPLC systems with common C18 columns provide the best performances in emulating the permeation of neutral compounds from aqueous solution through the human skin. As a result, a methodology based on easy, fast, and economical HPLC measurements in a common C18 column has been developed. After a validation based on training and test sets, the method has been applied with good results to the estimation of skin permeation of several hormones and pesticides. Copyright © 2013 Elsevier B.V. All rights reserved.

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.

A Gas Chromatographic Method for the Determination of Bicarbonate and Dissolved Gases

Directory of Open Access Journals (Sweden)

John H. Loughrin

2017-11-01

Full Text Available A gas chromatographic method for the rapid determination of aqueous carbon dioxide and its speciation into solvated carbon dioxide and bicarbonate is presented. One-half mL samples are injected through a rubber septum into 20-mL vials that are filled with 9.5 mL of 0.1 N HCl. A one mL portion of the headspace is withdrawn and injected onto a gas chromatograph equipped with a thermal conductivity detector. Using the dimensionless Henry's constant for carbon dioxide and an adaptation of the Henderson-Hasselbalch equation, carbon dioxide in the samples can be categorized among solvated, bicarbonate, and carbonate forms. Natural water samples as well as wastewater from a municipal sewage treatment plant and a swine rearing operation were analyzed by this method and the results compared favorably to those obtained by titration. Samples stored for up to 5 weeks showed no significant changes in carbon dioxide concentrations. In addition, using flame ionization and electron capture detectors, methane and nitrous oxide concentrations in the samples were also measured.

High-performance liquid chromatographic radioenzymatic assay for plasma catecyholamines

International Nuclear Information System (INIS)

Klaniecki, T.S.; Corder, C.N.; McDonald, R.H. Jr.; Feldman, J.A.

1977-01-01

A new assay method for plasma catecholamimes (CA) requiring only 50 μl has been developed, which uses high performance liquid chromatography (HPLC). The norepinephrine (NE), dopamine (D), and epinephrine (E) compounds found in plasma are radioactively o-methylated with S-[methyl- 3 H]-adenosyl-L-methionine ( 3 H-SAM) 3 H-SAM by the reaction of catechol-o-methyl transferase (COMT). The reaction is terminated and a standard mixture of nonradioactive o-methylated analogues of NE, D, and E is added to act as a carrier. Following separation by HPLC, the D,L-normetanephrine (NMN), 3-methoxy-4-hydroxyphenylethyl-amine or 3-methoxytyramine (3-MOT), and metanephrine (MN) radioactive peaks are collected which represent NE, D, and E, respectively. Then MNM and MN are oxidized to vanillin, and 3-MOT is acetylated. The products are subsequently separated by solvent extraction. This is necessary in order to avoid high radioactive blanks and to allow quantitation of the radioactivity by liquid scintillation spectrometry. The mean supine levels of NE, D, and E in normal subjects were respectively 182, 33, and 87 pg/ml of plasma. Similar assays on patients with pheochromocytoma revealed 797, 80, and 470 pg/ml

Development of new process network for gas chromatograph and analyzers connected with SCADA system and Digital Control Computers at Cernavoda NPP Unit 1

International Nuclear Information System (INIS)

Deneanu, Cornel; Popa Nemoiu, Dragos; Nica, Dana; Bucur, Cosmin

2007-01-01

The continuous monitoring of gas mixture concentrations (deuterium/ hydrogen/oxygen/nitrogen) accumulated in 'Moderator Cover Gas', 'Liquid Control Zone' and 'Heat Transport D 2 O Storage Tank Cover Gas', as well as the continuous monitoring of Heavy Water into Light Water concentration in 'Boilers Steam', 'Boilers Blown Down', 'Moderator heat exchangers', and 'Recirculated Water System', sensing any leaks of Cernavoda NPP U1 led to requirement of developing a new process network for gas chromatograph and analyzers connected to the SCADA system and Digital Control Computers of Cernavoda NPP Unit 1. In 2005 it was designed and implemented the process network for gas chromatograph which connected the gas chromatograph equipment to the SCADA system and Digital Control Computers of the Cernavoda NPP Unit 1. Later this process network for gas chromatograph has been extended to connect the AE13 and AE14 Fourier Transform Infrared (FTIR) analyzers with either. The Gas Chromatograph equipment measures with best accuracy the mixture gases (deuterium/ hydrogen/oxygen/nitrogen) concentration. The Fourier Transform Infrared (FTIR) AE13 and AE14 Analyzers measure the Heavy Water into Light Water concentration in Boilers Steam, Boilers BlownDown, Moderator heat exchangers, and Recirculated Water System, monitoring and signaling any leaks. The Gas Chromatograph equipment and Fourier Transform Infrared (FTIR) AE13 and AE14 Analyzers use the new OPC (Object Link Embedded for Process Control) technologies available in ABB's VistaNet network for interoperability with automation equipment. This new process network has interconnected the ABB chromatograph and Fourier Transform Infrared analyzers with plant Digital Control Computers using new technology. The result was an increased reliability and capability for inspection and improved system safety

High Performance Liquid Chromatographic Analysis of Almotriptan Malate in Bulk and Tablets

Directory of Open Access Journals (Sweden)

Chandra Bala Sekaran

2013-02-01

Full Text Available Purpose: A simple RP-HPLC method has been developed and validated for the determination of almotriptan malate (ATM in bulk and tablets. Methods: Chromatographic separation of ATM was achieved by using a Thermo Scientific C18 column. A Mobile phase containing a mixture of methanol, water and acetic acid (4:8:0.1 v/v was pumped at the flow rate of 1 mL/min. Detection was performed at 227 nm. According to ICH guidelines, the method was validated. Results: The calibration curve was linear in the concentration range 5–60 μg/mL for the ATM with regression coefficient 0.9999. The method was precise with RSD <1.2%. Excellent recoveries of 99.60 - 100.80% proved the accuracy of the method. The limits of detection and quantification were found to be 0.025 and 0.075 μg/mL, respectively. Conclusion: The method was successfully applied for the quantification of ATM in tablets with acceptable accuracy and precision.

Chromatographic quality control procedures for /sup 99m/Tc-diagnostic agents

International Nuclear Information System (INIS)

Marinelli, M.; Pozzato, R.; Garuti, P.; Zucchini, G.L.

1986-01-01

The purpose of this work was to experiment simple and rapid chromatographic systems, based on paper and thin-layer techniques, to test the radiochemical purity of some common /sup 99m/Tc diagnostic agents, and select those systems able to prevent the anomalies due to oxidation and artifact production. The agents were examined under conditions which usually bring about the above mentioned anomalies, then the results were compared with those obtained under controlled conditions. Quali- and quantitative detection of the activity present on the chromatograms was carried out using the equipment available in nuclear medicine departments

Solid-Phase Extraction Combined with High Performance Liquid ...

African Journals Online (AJOL)

Methods: Solid-phase extraction method was employed for the extraction of the estrogen from milk and high performance liquid chromatography-diode array detector (HPLC-DAD) was used for the determination of estrogen. Results: Optimal chromatographic conditions were achieved on an Eclipse XDB-C18 column at a ...

Liquid chromatographic-tandem mass spectrometric method for the simultaneous determination of alkylphenols polyethoxylates, alkylphenoxy carboxylates and alkylphenols in wastewater and surface-water.

Science.gov (United States)

Ciofi, L; Ancillotti, C; Chiuminatto, U; Fibbi, D; Checchini, L; Orlandini, S; Del Bubba, M

2014-10-03

Four different pellicular stationary phases (i.e. octadecylsilane, octasilane, Phenyl-Hexyl and pentafluorophenyl) were investigated for the chromatographic resolution of alkylphenols (APs), alkylphenols polyethoxylates (APnEOs) and alkylphenoxy carboxylates (APECs) using mixtures of water and organic solvents (i.e. methanol, acetonitrile and tetrahydrofuran) as eluents, in order to obtain their determination by a single LC-MS/MS run. In fact, alkylphenols and alkylphenoxy carboxylates must be analysed in negative ion mode, whereas alkylphenols polyethoxylates undergo ionisation only in positive ion mode, and therefore, two distinct LC-MS/MS analysis are commonly adopted. The best resolution among the aforementioned target analytes was achieved on the pentafluorophenyl column, eluting with an acidified water-acetonitrile-tetrahydrofuran mixture and using the post column addition of an ammonia solution in methanol for the detection of positively ionisable compounds. Under these optimized chromatographic conditions the investigated compounds were determined via a single chromatographic run, with only one polarity switch, in 15min, achieving the following instrumental detection limits: 600pg for AP1EOs, 0.8-14pg for AP2EOs, 10.4-150pg for APs and 4.4-4.8pg for APECs. The chromatographic method was coupled with solid-phase extraction and clean-up procedures and successfully applied to the analysis of wastewater and surface water samples, highlighting mean concentration ranging from 6ng/L for 4-t-OP1EC to 1434ng/L for 4-NP1121EC, depending on the sample analysed. Copyright © 2014 Elsevier B.V. All rights reserved.

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

African Journals Online (AJOL)

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

Probabilistic peak detection for first-order chromatographic data

NARCIS (Netherlands)

Lopatka, M.; Vivó-Truyols, G.; Sjerps, M.J.

2014-01-01

We present a novel algorithm for probabilistic peak detection in first-order chromatographic data. Unlike conventional methods that deliver a binary answer pertaining to the expected presence or absence of a chromatographic peak, our method calculates the probability of a point being affected by

Determination of trace bisphenol A in environmental water by high-performance liquid chromatography using magnetic reduced graphene oxide based solid-phase extraction coupled with dispersive liquid-liquid microextraction.

Science.gov (United States)

Li, Danping; Ma, Xiaoguo; Wang, Rui; Yu, Yumian

2017-02-01

Bisphenol A (BPA), an endocrine-disrupting chemical, has received much attention from researchers and the general public. In this paper, a novel method of determining BPA at trace levels was developed, using magnetic reduced graphene oxide (rGO-Fe 3 O 4 )-based solid-phase extraction coupled with dispersive liquid-liquid microextraction (DLLME), followed by high-performance liquid chromatographic determination. The rGO-Fe 3 O 4 was prepared and then characterized by Fourier transform infrared spectroscopy, transmission electron microscopy, and vibrating sample magnetometry. The greatest saturation magnetization of rGO-Fe 3 O 4 was up to 43.8 emu g -1 , which allowed rapid isolation of the rGO-Fe 3 O 4 from solutions upon applying an appropriate magnetic field. The effects of solution pH, adsorbent amount, type and volume of eluent and extraction solvent, extraction time, and salt concentration on the extraction efficiency of BPA were examined and optimized. Under the optimum conditions, an enrichment factor of 5217 and an LOD of 0.01 μg L -1 for BPA were obtained. The reusability of rGO-Fe 3 O 4 for at least 12 repeated cycles without any significant decrease in the extraction recovery of BPA was demonstrated. The proposed method was applied to the determination of BPA in different real water samples, with relative recoveries of 84.8-104.9 % and RSDs of 0.8-8.3 % in the spiked concentration range 1-10 μg L -1 .

A New High-Performance Liquid Chromatographic Method for the Determination and Distribution of Linalool in Michelia alba

Directory of Open Access Journals (Sweden)

Hua-Bin Li

2010-07-01

Full Text Available A new high-performance liquid chromatographic method with photodiode array detection was established for the determination of linalool in the plant Michelia alba. Linalool was extracted from the plant sample with the aid of ultrasound, and was analyzed on a Waters RP C18 column (4.6 × 150 mm, 5 μm using an acetonitrile and water (55:45, v/v mobile phase at a flow rate of 1.0 mL/min. The column temperature was set at 25 ºC, and the detection wavelength was 210 nm. The linear range of the method was 5–200 μg/mL with a correlation coefficient of 0.9975. The recovery was 92–112%, and the relative standard deviation was 1.85% (n = 9. The present method has been used to study the distribution of linalool in the plant Michelia alba. The plant samples include flowers, leaves and tender twigs. Furthermore, leaves included samples in their tender, grown-up and fallen phases, and flowers included samples in their juvenile, middle and whitening phases. The concentrations of linalool in different parts of the plant were 0.21–0.65%, 1.63–4.89% and 0.43% for leaves, flowers and tender twigs, respectively. The results showed that all the plant materials contained relative high concentration of linalool, and juvenile phase flowers contained the highest concentration of linalool. Notably, the fallen leaves also contained high concentrations of linalool, which could be a potential resource of this compound. The results obtained are very helpful for the potential full utilization of this plant.

Quantitative determination of sirolimus in dog blood using liquid chromatography-tandem mass spectrometry, and its applications to pharmacokinetic studies.

Science.gov (United States)

Lee, Jong-Hwa; Cha, Kwang-Ho; Cho, Wonkyung; Park, Junsung; Park, Hee Jun; Cho, Youngseok; Hwang, Sung-Joo

2010-12-01

A rapid, sensitive method of detecting sirolimus in blood was developed and applied in pharmacokinetic studies employing deionized water for hemolysis and a weakly basic mobile phase to enhance chromatographic peak intensity. Dog blood samples were processed via liquid-liquid extraction and the amounts of sirolimus and tacrolimus, an internal standard, were quantified by LC-MS/MS. Specificity, the lower limit of quantification, linearity, accuracy, precision, dilution, recovery, matrix effects, robustness and stability were within the acceptable range for assay validation. The concentration of sirolimus was quantifiable in blood samples for up to 36 h after the dog had received a 3 mg/kg dose of sirolimus. These observations suggest that sirolimus can be detected at low levels in dog blood using a basic mobile phase and metal-free hemolysis. This method is therefore applicable to pharmacokinetic studies in dogs. Copyright (c) 2010 Elsevier B.V. All rights reserved.

Separation of tungsten from molybdenum by liquid-liquid extraction and extraction chromatography using thiocyanate and a quarternary ammonium salt

International Nuclear Information System (INIS)

Yonezawa, C.; Onishi, H.

1977-01-01

Methods were developed for the separation of tungsten from molybdenum by liquid-liquid extraction and extraction chromatography using thiocyanate and a quaternary ammonium salt, Zephiramine. Tungsten was extracted into chloroform as an ion associate of tungsten(V)-thiocyanate complex and Zephiramine cation was retained on a column of Teflon powder coated with Zephiramine, but molybdenum(III) was neither extracted nor retained. The extraction chromatographic method was succesfully applied to the determination of trace amounts of tungsten in molybdenum by neutron activation analysis. The γ-ray spectrum, observed with the Ge(Li) detector, of tungsten fraction separated from irradiated molybdenum are shown. The peaks of 99 Mo, sup(99m)Tc, and sup(99m)Nb (produced by 92 Mo(n,p)sup(99m)Nb) were seen, but these nuclides did nit interfere with the determination of tungsten using a NaI(Tl) detector. The results of the neutron activation analysis of a sample of ammonium molybdate agreed quite well with that of the spectrophotometric determination after extraction chromatographic separation. (T.G.)

Optimisation of chromatographic resolution using objective functions including both time and spectral information.

Science.gov (United States)

Torres-Lapasió, J R; Pous-Torres, S; Ortiz-Bolsico, C; García-Alvarez-Coque, M C

2015-01-16

The optimisation of the resolution in high-performance liquid chromatography is traditionally performed attending only to the time information. However, even in the optimal conditions, some peak pairs may remain unresolved. Such incomplete resolution can be still accomplished by deconvolution, which can be carried out with more guarantees of success by including spectral information. In this work, two-way chromatographic objective functions (COFs) that incorporate both time and spectral information were tested, based on the peak purity (analyte peak fraction free of overlapping) and the multivariate selectivity (figure of merit derived from the net analyte signal) concepts. These COFs are sensitive to situations where the components that coelute in a mixture show some spectral differences. Therefore, they are useful to find out experimental conditions where the spectrochromatograms can be recovered by deconvolution. Two-way multivariate selectivity yielded the best performance and was applied to the separation using diode-array detection of a mixture of 25 phenolic compounds, which remained unresolved in the chromatographic order using linear and multi-linear gradients of acetonitrile-water. Peak deconvolution was carried out using the combination of orthogonal projection approach and alternating least squares. Copyright © 2014 Elsevier B.V. All rights reserved.

Application of Analytical Quality by Design concept for bilastine and its degradation impurities determination by hydrophilic interaction liquid chromatographic method.

Science.gov (United States)

Terzić, Jelena; Popović, Igor; Stajić, Ana; Tumpa, Anja; Jančić-Stojanović, Biljana

2016-06-05

This paper deals with the development of hydrophilic interaction liquid chromatographic (HILIC) method for the analysis of bilastine and its degradation impurities following Analytical Quality by Design approach. It is the first time that the method for bilastine and its impurities is proposed. The main objective was to identify the conditions where an adequate separation in minimal analysis duration could be achieved within a robust region. Critical process parameters which have the most influence on method performance were defined as acetonitrile content in the mobile phase, pH of the aqueous phase and ammonium acetate concentration in the aqueous phase. Box-Behnken design was applied for establishing a relationship between critical process parameters and critical quality attributes. The defined mathematical models and Monte Carlo simulations were used to identify the design space. Fractional factorial design was applied for experimental robustness testing and the method is validated to verify the adequacy of selected optimal conditions: the analytical column Luna(®) HILIC (100mm×4.6mm, 5μm particle size); mobile phase consisted of acetonitrile-aqueous phase (50mM ammonium acetate, pH adjusted to 5.3 with glacial acetic acid) (90.5:9.5, v/v); column temperature 30°C, mobile phase flow rate 1mLmin(-1), wavelength of detection 275nm. Copyright © 2016 Elsevier B.V. All rights reserved.

Rapid Quantification and Quantitation of Alkaloids in Xinjiang Fritillaria by Ultra Performance Liquid Chromatography-Quadrupole Time-of-Flight Mass Spectrometry

Directory of Open Access Journals (Sweden)

Aziz Mohammat

2017-05-01

Full Text Available The Fritillaria genus, including different kinds of medicinal and edible plants belonging to the Liliaceae family which have the function of treating and relieving a cough and eliminating phlegm, is widely planted in Xinjiang (China. There are few comprehensive studies reporting on the characterization of the chemical constituents of Fritillaria from Xinjiang, and to date, no work describing the quantitative differences between the components in Fritillaria from Xinjiang and related species. The purpose of this study was to develop qualitative and quantitative analytical methods by Ultra Performance Liquid Chromatography-Quadrupole Time-of-flight Mass Spectrometry (UPLC-QTOF-MS for the rapid quantification and quantitation of alkaloids in wild and cultivated Xinjiang Fritillaria, which could be used in the quality control of medicine based on this natural herb. Using the UPLC-QTOF-MS method, the chemical constituents of Xinjiang Fritillaria were identified by fragmentation information and retention behavior, and were compared to reference standards. Furthermore, a quantitative comparision of four major alkaloids in wild and cultivated Xinjiang Fritillaria was conducted by determining the content of Sipeimine-3β-d-glucoside, Sipeimine, Peimisine, and Yibeinoside A, respectively. A total of 89 characteristic peaks, including more than 40 alkaloids, were identified in the chromatographic results of Fritillaria. Four main alkaloids were quantified by using a validated method based on UPLC-QTOF-MS. The relative contents of Sipeimine-3β-d-glucoside, Sipeimine, Peimisine, and Yibeinoside A varied from 0.0013%~0.1357%, 0.0066%~0.1218%, 0.0033%~0.0437%, and 0.0019%~0.1398%, respectively. A rough separation of wild and cultivated Fritillaria could be achieved by the cluster analysis method.

Reduction of silanophilic interactions in liquid chromatography with the use of ionic liquids

Energy Technology Data Exchange (ETDEWEB)

MarszaII, MichaI Piotr [Department of Biopharmaceutics and Pharmacodynamics, Medical University of Gdansk, Gen. J. Hallera 107, 80-416 Gdansk (Poland); Baczek, Tomasz [Department of Biopharmaceutics and Pharmacodynamics, Medical University of Gdansk, Gen. J. Hallera 107, 80-416 Gdansk (Poland); Kaliszan, Roman [Department of Biopharmaceutics and Pharmacodynamics, Medical University of Gdansk, Gen. J. Hallera 107, 80-416 Gdansk (Poland)]. E-mail: roman.kaliszan@amg.gda.pl

2005-08-22

A suppression of silanophilic interactions by the selected ionic liquids added to the mobile phase in thin-layer chromatography (TLC) and high-performance liquid chromatography (HPLC) is reported. Acetonitrile was used as the eluent, alone or with various concentrations of water and phosphoric buffer pH 3. Selectivity of the normal (NP) and the reversed (RP) stationary phase material was examined using a series of proton-acceptor basic drugs analytes. The ionic liquids studied appeared to significantly affect analyte retention in NP-TLC, RP-TLC and RP-HPLC systems tested. Consequently, the increased separation selectivity was attained. Due to ionic liquid additives to eluent even analytes could be chromatographed, which were not eluted from the silica-based stationary phase materials with 100% of acetonitrile in the mobile phase. Addition of ionic liquid already in very small concentration (0.5%, v/v) could reduce the amount of acetonitrile used during the optimization of basic analytes separations in TLC and HPLC systems. Moreover, the influence of temperature on the separation of basic analytes was demonstrated and considered in practical HPLC method development.

Reduction of silanophilic interactions in liquid chromatography with the use of ionic liquids

International Nuclear Information System (INIS)

MarszaII, MichaI Piotr; Baczek, Tomasz; Kaliszan, Roman

2005-01-01

A suppression of silanophilic interactions by the selected ionic liquids added to the mobile phase in thin-layer chromatography (TLC) and high-performance liquid chromatography (HPLC) is reported. Acetonitrile was used as the eluent, alone or with various concentrations of water and phosphoric buffer pH 3. Selectivity of the normal (NP) and the reversed (RP) stationary phase material was examined using a series of proton-acceptor basic drugs analytes. The ionic liquids studied appeared to significantly affect analyte retention in NP-TLC, RP-TLC and RP-HPLC systems tested. Consequently, the increased separation selectivity was attained. Due to ionic liquid additives to eluent even analytes could be chromatographed, which were not eluted from the silica-based stationary phase materials with 100% of acetonitrile in the mobile phase. Addition of ionic liquid already in very small concentration (0.5%, v/v) could reduce the amount of acetonitrile used during the optimization of basic analytes separations in TLC and HPLC systems. Moreover, the influence of temperature on the separation of basic analytes was demonstrated and considered in practical HPLC method development

Chemometric approach for development, optimization, and validation of different chromatographic methods for separation of opium alkaloids.

Science.gov (United States)

Acevska, J; Stefkov, G; Petkovska, R; Kulevanova, S; Dimitrovska, A

2012-05-01

The excessive and continuously growing interest in the simultaneous determination of poppy alkaloids imposes the development and optimization of convenient high-throughput methods for the assessment of the qualitative and quantitative profile of alkaloids in poppy straw. Systematic optimization of two chromatographic methods (gas chromatography (GC)/flame ionization detector (FID)/mass spectrometry (MS) and reversed-phase (RP)-high-performance liquid chromatography (HPLC)/diode array detector (DAD)) for the separation of alkaloids from Papaver somniferum L. (Papaveraceae) was carried out. The effects of various conditions on the predefined chromatographic descriptors were investigated using chemometrics. A full factorial linear design of experiments for determining the relationship between chromatographic conditions and the retention behavior of the analytes was used. Central composite circumscribed design was utilized for the final method optimization. By conducting the optimization of the methods in very rational manner, a great deal of excessive and unproductive laboratory research work was avoided. The developed chromatographic methods were validated and compared in line with the resolving power, sensitivity, accuracy, speed, cost, ecological aspects, and compatibility with the poppy straw extraction procedure. The separation of the opium alkaloids using the GC/FID/MS method was achieved within 10 min, avoiding any derivatization step. This method has a stronger resolving power, shorter analysis time, better cost/effectiveness factor than the RP-HPLC/DAD method and is in line with the "green trend" of the analysis. The RP-HPLC/DAD method on the other hand displayed better sensitivity for all tested alkaloids. The proposed methods provide both fast screening and an accurate content assessment of the six alkaloids in the poppy samples obtained from the selection program of Papaver strains.

A new modeling strategy for third-order fast high-performance liquid chromatographic data with fluorescence detection. Quantitation of fluoroquinolones in water samples.

Science.gov (United States)

Alcaráz, Mirta R; Bortolato, Santiago A; Goicoechea, Héctor C; Olivieri, Alejandro C

2015-03-01

Matrix augmentation is regularly employed in extended multivariate curve resolution-alternating least-squares (MCR-ALS), as applied to analytical calibration based on second- and third-order data. However, this highly useful concept has almost no correspondence in parallel factor analysis (PARAFAC) of third-order data. In the present work, we propose a strategy to process third-order chromatographic data with matrix fluorescence detection, based on an Augmented PARAFAC model. The latter involves decomposition of a three-way data array augmented along the elution time mode with data for the calibration samples and for each of the test samples. A set of excitation-emission fluorescence matrices, measured at different chromatographic elution times for drinking water samples, containing three fluoroquinolones and uncalibrated interferences, were evaluated using this approach. Augmented PARAFAC exploits the second-order advantage, even in the presence of significant changes in chromatographic profiles from run to run. The obtained relative errors of prediction were ca. 10 % for ofloxacin, ciprofloxacin, and danofloxacin, with a significant enhancement in analytical figures of merit in comparison with previous reports. The results are compared with those furnished by MCR-ALS.

A simple and rapid gas chromatographic method for the determination of dissolved deuterium and nitrogen in heavy water coolant of a nuclear reactor

International Nuclear Information System (INIS)

Nair, B.K.S.

1976-01-01

A known volume of a heavy water sample is equilibrated with a known volume of pure helium gas at atmospheric pressure in a sample tube. The dissolved gases evolve into the helium and distribute themselves between the gaseous and liquid phases according to their equilibrium partial pressures. These partial pressures of the gases in the equilibrium gas mixture are determined by analysing it gas-chromatographically. From these analytical data and the absorption coefficients of deuterium and nitrogen, their original concentrations in heavy water are calculated. Corrections for the increase in the total pressure of the gaseous phase owing to evolved gases are calculated and found to be negligible. Air contamination during sampling and analysis can be detected by the presence of the oxygen peak in the chromatogram and corrected for. The calculation is facilitated by programming it on an electronic calculator. The method is much simpler and faster than the vacuum method usually applied for this analysis. One determination can be completed in about an hour. The average deviation and standard deviation have been estimated at 0.19 ml/litre heavy water and 0.25 ml/litre heavy water respectively in deuterium, and 0.36 and 0.68 ml/litre in nitrogen. (author)

A simple and rapid chromatographic method to determine unauthorized basic colorants (rhodamine B, auramine O, and pararosaniline) in processed foods.

Science.gov (United States)

Tatebe, Chiye; Zhong, Xining; Ohtsuki, Takashi; Kubota, Hiroki; Sato, Kyoko; Akiyama, Hiroshi

2014-09-01

A simple and rapid high-performance liquid chromatography (HPLC) method to determine basic colorants such as pararosaniline (PA), auramine O (AO), and rhodamine B (RB) in various processed foods was developed. Linearity of the calibration curves ranged from 0.05 to 50 μg/mL for PA and 0.05-100 μg/mL for AO and RB. The detection and quantification limits (LOD and LOQ) of the basic colorants, which were evaluated as signal-to-noise ratios of 3 for LOD and 10 for LOQ, ranged from 0.0125 to 0.05 and 0.025 to 0.125 μg/g, respectively. The recoveries and relative standard deviations of three basic colorants in six processed foods, namely, chili sauce, curry paste, gochujang (hot pepper paste), tandoori chicken (roasted chicken prepared with yogurt and spices), powder soup, and shrimp powder ranged from 70.2% to 102.8% and 0.8% to 8.0%, respectively. The intraday precision of the recovery test ranged from 1.7% to 4.5%, whereas the interday precision ranged from 3.7% to 7.7%. The reported method has been successfully applied to basic colorant determination in various processed foods such as fat-based food matrices (curry paste and tandoori chicken), chili products (gochujang and chili sauce), and protein-based products (shrimp powder and powder soup). Thin layer chromatography and liquid chromatography/mass spectrometry methods for the determination of basic colorants in processed foods were also developed for rapid analysis and identification, respectively. These methods are very useful for monitoring unauthorized basic colorants in inspection centers or quarantine laboratories in many countries.

Rapid profiling of antimicrobial compounds characterising B. subtilis TR50 cell-free filtrate by high-performance liquid chromatography coupled to high-resolution Orbitrap™ mass spectrometry.

Science.gov (United States)

Monaci, Linda; Quintieri, Laura; Caputo, Leonardo; Visconti, Angelo; Baruzzi, Federico

2016-01-15

Several Bacillus strains, typically isolated from different food sources, represent renowned producers of a multitude of low and high molecular weight compounds, including lipopeptides and macrolactones, with an importance for their antimicrobial activity. The high homology shared by many of these compounds also occurring as closely related isoforms poses a challenge in their prompt detection. Identification and structural elucidation is generally achieved by matrix-assisted laser desorption/ionization (MALDI) or liquid chromatography (LC) coupled to mass spectrometry (MS) after a pre-fractionation and/or purification step of the extract. In this paper we report the application of a method based on LC separation and high-resolution Orbitrap™-based MS for the rapid screening of raw filtrate of the strain Bacillus subtilis TR50 endowed with antimicrobial activity, without requiring any sample pre-treatment. Upon direct analysis of the cell-free filtrate of Bacillus subtilis TR50 by high-resolution mass spectrometry (HRMS), different compounds families, that proved to exert a remarked antimicrobial activity against several foodborne pathogens, can be readily displayed along the chromatographic run. Among them, three different classes were identified and characterized belonging to the iturin, fengycin and surfactin groups. The high resolving power and accurate mass accuracy provided by the HRMS system in use ensured an enhanced selectivity compared to other mass spectrometers. In addition, after activation of the HCD cell, the HR-MS/MS spectra can provide insights in the structural elucidation of several compounds. The acquisition of HRMS spectra of raw filtrates of subtilis strains allows untargeted analysis of the major classes of compounds produced to be performed, thus facilitating identification of other unknown bioactive molecules after retrospective analysis. These features make this approach a fast tool applicable to the rapid screening and further

Supercooled liquid vapour pressures and related thermodynamic properties of polycyclic aromatic hydrocarbons determined by gas chromatography

NARCIS (Netherlands)

Haftka, J.J.H.; Parsons, J.R.; Govers, H.A.J.

2006-01-01

A gas chromatographic method using Kovats retention indices has been applied to determine the liquid vapour pressure (P-i), enthalpy of vaporization (Delta H-i) and difference in heat capacity between gas and liquid phase (Delta C-i) for a group of polycyclic aromatic hydrocarbons (PAHs). This group

A review of chromatographic methods for the determination of water- and fat-soluble vitamins in biological fluids.

Science.gov (United States)

Karaźniewicz-Łada, Marta; Główka, Anna

2016-01-01

Vitamins are an essential element of nutrition and thus contribute to human health. Vitamins catalyze many biochemical reactions and their lack or excess can cause health problems. Therefore, monitoring vitamin concentrations in plasma or other biological fluids may be useful in the diagnosis of various disorders as well as in the treatment process. Several chromatographic methods have been developed for the determination of these compounds in biological samples, including high-performance liquid chromatography with UV and fluorescence detection. Recently, high-performance liquid chromatography with tandem mass spectrometry methods have been widely used for the determination of vitamins in complex matrices because of their high sensitivity and selectivity. This method requires preconditioning of samples for analysis, including protein precipitation and/or various extraction techniques. The choice of method may depend on the desired cost, convenience, turnaround time, specificity, and accuracy of the information to be obtained. This article reviews the recently reported chromatographic methods used for determination of vitamins in biological fluids. Relevant papers published mostly during the last 5 years were identified by an extensive PubMed search using appropriate keywords. Particular attention was given to the preparation steps and extraction techniques. This report may be helpful in the selection of procedures that are appropriate for certain types of biological materials and analytes. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A Novel Two-Step Liquid-Liquid Extraction Procedure Combined with Stationary Phase Immobilized Human Serum Albumin for the Chiral Separation of Cetirizine Enantiomers along with M and P Parabens

Directory of Open Access Journals (Sweden)

Aleksandra Chmielewska

2016-12-01

Full Text Available The research into the separation of drug enantiomers is closely related to the safety and efficiency of the drugs. The aim of this study was to develop a simple and validated HPLC method to analyze cetirizine enantiomers. In the case of liquid dosage forms, besides the active substance in large amounts there are usually also inactive ingredients such as methyl- and propylparaben. Unfortunately, these compounds can interfere with the analyte, inter alia during chiral separation of the analyte enantiomers. The proposed innovative two-step liquid-liquid extraction procedure allowed for the determination of cetirizine enantiomers (along with M and P parabens also in liquid dosage forms. The main focus of this study was the chromatographic activity of cetirizine dihydrochloride on the proteinate-based chiral stationary phase. The chromatographic separation of cetirizine enantiomers was performed on an immobilized human serum albumin (HSA column for the first time. Measurements were performed at a wavelength of 227 nm. Under optimal conditions, baseline separation of two enantiomers was obtained with 1.43 enantioseparation factor (α and 1.82 resolution (Rs. Finally, the proposed method was successfully applied to the selected pharmaceutical formulations.

Rapid and sensitive liquid chromatography-tandem mass spectrometric method for the quantitative determination of potentially harmful substance 5,5'-oxydimethylenebis (2-furfural) in traditional Chinese medicine injections.

Science.gov (United States)

Zang, Qingce; Gao, Yang; Huang, Luojiao; He, Jiuming; Lin, Sheng; Jin, Hongtao; Zhang, Ruiping; Abliz, Zeper

2018-03-01

With the rapid development and wide application of traditional Chinese medicine injection (TCMI), a number of adverse events of some TCMIs have incessantly been reported and have drawn broad attention in recent years. Establishing effective and practical analytical methods for safety evaluation and quality control of TCMI can help to improve the safety of TCMIs in clinical applications. In this study, a sensitive and rapid high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method has been developed and validated for the quantitative determination of potentially harmful substance 5,5'-oxydimethylenebis (2-furfural, OMBF) in TCMI samples. Chromatographic separation was performed on a C18 reversed-phase column (150 mm × 2.1 mm, 5 µm) by gradient elution, using methanol-water containing 0.1% formic acid as mobile phase at the flow rate of 0.3 mL/min. MS/MS detection was performed on a triple quadrupole mass spectrometer with positive electrospray ionization in the multiple reaction-monitoring mode. The method was sensitive with a limit of quantification of 0.3 ng/mL and linear over the range of 0.3-30 ng/mL ( r =0.9998). Intra- and inter-day precision for analyte was <9.52% RSD with recoveries in the range 88.0-109.67% at three concentration levels. The validated method was successfully applied to quantitatively determine the compound OMBF in TCMIs and glucose injections. Our study indicates that this method is simple, sensitive, practicable and reliable, and could be applied for safety evaluation and quality control of TCMIs and glucose injections.

High-performance liquid chromatographic method for the determination and pharmacokinetic study of oxypeucedanin hydrate and byak-angelicin after oral administration of Angelica dahurica extracts in mongrel dog plasma.

Science.gov (United States)

Xie, Ying; Chen, Yi; Lin, Mei; Wen, Jun; Fan, Guorong; Wu, Yutian

2007-05-09

A high-performance liquid chromatographic method was developed and validated for the determination and pharmacokinetic study of oxypeucedanin hydrate and byak-angelicin after oral administration of Angelica dahurica extracts in mongrel dog plasma. The coumarin components and the internal standard isopsoralen were extracted from plasma samples with the mixture of tert-butyl methyl ether and n-hexane (4:1, v/v). Chromatographic separation was performed on a C(18) column (200 mm x 4.6mm, 5 microm) with the mobile phase acetonitrile-methanol-water-acetic acid (20:15:65:2, v/v/v/v) at a flow-rate of 1.0 ml/min. Only the peak of oxypeucedanin hydrate and byak-angelicin could be detected in dog plasma after oral administration of ethanol extracts of A. dahurica mainly containing xanthotoxol, osthenol, imperatorin, oxypeucedanin hydrate and byak-angelicin. The calibration curves of oxypeucedanin hydrate and byak-angelicin were linear over a range of 22.08-8830.00 and 6.08-2430.00 ng/ml in dog plasma, respectively. The quantification limit of oxypeucedanin hydrate and byak-angelicin in dog plasma was 22.08 and 6.08 ng/ml, respectively. The intra- and inter-day precision was less than 7.6% and 8.5% and the accuracy was from 91.9% to 106.1%. The lowest absolute recoveries of oxypeucedanin hydrate and byak-angelicin were 85.7% and 87.0%, respectively. The method was successfully applied to the pharmacokinetic studies of oxypeucedanin hydrate and byak-angelicin in dog plasma after oral administration of ethanol extracts from A. dahurica.

Effect of chromatographic separation on ASP system interface tension and the countermeasures

Directory of Open Access Journals (Sweden)

Jiawei REN

2016-06-01

Full Text Available Because of the existing chromatographic separation phenomenon, ASP flooding changes original nature of the system. Therefore, in laboratory ultra-low interfacial tension ASP system is preferred for sand packs flow experiment to research on the effect of chromatographic separation on ASP system interface tension. The two parameters of "breakthrough time" and "output difference" are used to describe the degree of chromatographic separation, and the produced fluid interfacial tensions at the outlet end at 120 min is measured. The research shows that there exists chromatographic separation between three chemicals of ASP system, with first polymer breakthrough and finally surfactant breakthrough; there is most serious chromatographic separation between surfactant and polymer, while minimum chromatographic separation between alkali and polymer; chromatographic separation makes ASP interfacial tension increase from 10^-3 magnitude to 10^-2 magnitude, affecting flooding effect of ASP system. Thus, reducing the loss of surfactant in the formation will be the main measure to reduce the degree of chromatographic separation. Using sophorolipid as sacrificial agent to replace part of the surfactant injected into formation before ASP system can effectively reduce the impact of chromatography separation and more effectively improve the ultimate recovery ratio.

Ionic liquid-based single-drop microextraction/gas chromatographic/mass spectrometric determination of benzene, toluene, ethylbenzene and xylene isomers in waters.

Science.gov (United States)

Aguilera-Herrador, Eva; Lucena, Rafael; Cárdenas, Soledad; Valcárcel, Miguel

2008-08-01

The direct coupling between ionic liquid-based single-drop microextraction and gas chromatography/mass spectrometry is proposed for the rapid and simple determination of benzene, toluene, ethylbenzene and xylenes isomers (BTEX) in water samples. The extraction procedure exploits not only the high affinity of the selected ionic liquid (1-methyl-3-octyl-imidazolium hexaflourophosphate) to these aromatic compounds but also its special properties like viscosity, low vapour pressure and immiscibility with water. All the variables involved in the extraction process have been studied in depth. The developed method allows the determination of these single-ring compounds in water under the reference concentration level fixed by the international legislation. In this case, limits of detection were in the range 20 ng L(-1) (obtained for benzene) and 91 ng L(-1) (for o-xylene). The repeatability of the proposed method, expressed as RSD (n=5), varied between 3.0% (o-xylene) and 5.2% (toluene).

Chromatographic Separation of Vitamin E Enantiomers

Directory of Open Access Journals (Sweden)

Ju-Yen Fu

2017-02-01

Full Text Available Vitamin E is recognized as an essential vitamin since its discovery in 1922. Most vegetable oils contain a mixture of tocopherols and tocotrienols in the vitamin E composition. Structurally, tocopherols and tocotrienols share a similar chromanol ring and a side chain at the C-2 position. Owing to the three chiral centers in tocopherols, they can appear as eight different stereoisomers. Plant sources of tocopherol are naturally occurring in the form of RRR while synthetic tocopherols are usually in the form of all-racemic mixture. Similarly, with only one chiral center, natural tocotrienols occur as the R-isoform. In this review, we aim to discuss a few chromatographic methods that had been used to separate the stereoisomers of tocopherols and tocotrienols. These methods include high performance liquid chromatography, gas chromatography and combination of both. The review will focus on method development including selection of chiral columns, detection method and choice of elution solvent in the context of separation efficiency, resolution and chiral purity. The applications for separation of enantiomers in vitamin E will also be discussed especially in terms of the distinctive biological potency among the stereoisoforms.

Advanced hyphenated chromatographic-mass spectrometry in mycotoxin determination: current status and prospects.

Science.gov (United States)

Li, Peiwu; Zhang, Zhaowei; Hu, Xiaofeng; Zhang, Qi

2013-01-01

Mass spectrometric techniques are essential for advanced research in food safety and environmental monitoring. These fields are important for securing the health of humans and animals, and for ensuring environmental security. Mycotoxins, toxic secondary metabolites of filamentous fungi, are major contaminants of agricultural products, food and feed, biological samples, and the environment as a whole. Mycotoxins can cause cancers, nephritic and hepatic diseases, various hemorrhagic syndromes, and immune and neurological disorders. Mycotoxin-contaminated food and feed can provoke trade conflicts, resulting in massive economic losses. Risk assessment of mycotoxin contamination for humans and animals generally depends on clear identification and reliable quantitation in diversified matrices. Pioneering work on mycotoxin quantitation using mass spectrometry (MS) was performed in the early 1970s. Now, unambiguous confirmation and quantitation of mycotoxins can be readily achieved with a variety hyphenated techniques that combine chromatographic separation with MS, including liquid chromatography (LC) or gas chromatography (GC). With the advent of atmospheric pressure ionization, LC-MS has become a routine technique. Recently, the co-occurrence of multiple mycotoxins in the same sample has drawn an increasing amount of attention. Thus, modern analyses must be able to detect and quantitate multiple mycotoxins in a single run. Improvements in tandem MS techniques have been made to achieve this purpose. This review describes the advanced research that has been done regarding mycotoxin determination using hyphenated chromatographic-MS techniques, but is not a full-circle survey of all the literature published on this topic. The present work provides an overview of the various hyphenated chromatographic-MS-based strategies that have been applied to mycotoxin analysis, with a focus on recent developments. The use of chromatographic-MS to measure levels of mycotoxins, including

Dose Uniformity of Over-the-Counter Melatonin as Determined by High-Pressure Liquid Chromatography

National Research Council Canada - National Science Library

Prazinko, B

2000-01-01

.... A liquid chromatograph equipped with a C-18 microbore column was used in conjunction with an autosampler to perform two runs per tablet, while also running intermittent standards on a regular basis...

Evaluation of pesticide adsorption in gas chromatographic injector and column

Directory of Open Access Journals (Sweden)

Gevany Paulino de Pinho

2012-01-01

Full Text Available Components in complex matrices can cause variations in chromatographic response during analysis of pesticides by gas chromatography. These variations are related to the competition between analytes and matrix components for adsorption sites in the chromatographic system. The capacity of the pesticides chlorpyrifos and deltamethrin to be adsorbed in the injector and chromatographic column was evaluated by constructing three isotherms and changing the column heating rate to 10 and 30 ºC min-1. By using ANCOVA to compare the slope of calibration graphs, results showed that the higher the injector temperature (310 ºC the lower the pesticide adsorption. Also, deltamethrin influenced the adsorption of chlorpyrifos on the column chromatographic.

Probabilistic classification method on multi wavelength chromatographic data for photosynthetic pigments identification

Science.gov (United States)

Prilianti, K. R.; Setiawan, Y.; Indriatmoko, Adhiwibawa, M. A. S.; Limantara, L.; Brotosudarmo, T. H. P.

2014-02-01

Environmental and health problem caused by artificial colorant encourages the increasing usage of natural colorant nowadays. Natural colorant refers to the colorant that is derivate from living organism or minerals. Extensive research topic has been done to exploit these colorant, but recent data shows that only 0.5% of the wide range of plant pigments in the earth has been exhaustively used. Hence development of the pigment characterization technique is an important consideration. High-performance liquid chromatography (HPLC) is a widely used technique to separate pigments in a mixture and identify it. In former HPLC fingerprinting, pigment characterization was based on a single chromatogram from a fixed wavelength (one dimensional) and discard the information contained at other wavelength. Therefore, two dimensional fingerprints have been proposed to use more chromatographic information. Unfortunately this method leads to the data processing problem due to the size of its data matrix. The other common problem in the chromatogram analysis is the subjectivity of the researcher in recognizing the chromatogram pattern. In this research an automated analysis method of the multi wavelength chromatographic data was proposed. Principal component analysis (PCA) was used to compress the data matrix and Maximum Likelihood (ML) classification was applied to identify the chromatogram pattern of the existing pigments in a mixture. Three photosynthetic pigments were selected to show the proposed method. Those pigments are β-carotene, fucoxanthin and zeaxanthin. The result suggests that the method could well inform the existence of the pigments in a particular mixture. A simple computer application was also developed to facilitate real time analysis. Input of the application is multi wavelength chromatographic data matrix and the output is information about the existence of the three pigments.

Supramolecular solvent-based extraction of benzimidazolic fungicides from natural waters prior to their liquid chromatographic/fluorimetric determination.

Science.gov (United States)

Moral, Antonia; Sicilia, María Dolores; Rubio, Soledad

2009-05-01

A supramolecular solvent made up of vesicles of decanoic acid in the nano- and microscale regimes dispersed in a continuous aqueous phase is proposed for the extraction/preconcentration of benzimidazolic fungicides (BFs) from river and underground water samples prior to their determination by liquid chromatography (LC)/fluorimetry. The solvent is produced from the coacervation of decanoic acid aqueous vesicles by the action of tetrabutylammonium (Bu(4)N(+)). Carbendazim (CB), thiabendazole (TB) and fuberidazole (FB) are extracted on the basis of hydrophobic and pi-cation interactions and the formation of hydrogen bonds. The extraction provides high preconcentration factors (160 for CB and 190 for TB and FB), requires a short time (the procedure takes less than 20 min and several samples can be simultaneously processed) and a low sample volume (20 mL), and avoids the use of toxic organic solvents. Because of the absence of matrix interferences and the low viscosity of the extracts, these can be directly injected into the chromatographic system without the need of cleaning-up or diluting them. Recoveries are not influenced by the presence of salt concentrations up to 1 M. The proposed method provides detection limits for the determination of CB, TB and FB in natural waters of 32, 4 and 0.1 ng L(-1), respectively, and a precision, expressed as relative standard deviation (n=11) of 5.5% for CB (100 ng L(-1)), 4.0% for TB (80 ng L(-1)) and 2.5% for FB (30 ng L(-1)). Recoveries obtained by applying this approach to the analysis of river and underground water samples fortified at the ng L(-1) level are in the intervals 75-83, 95-102 and 97-101% for CB, TB and FB, respectively.

Reductive amination of glutaraldehyde 2,4-dinitrophenylhydrazone using 2-picoline borane and high-performance liquid chromatographic analysis.

Science.gov (United States)

Uchiyama, Shigehisa; Sakamoto, Hironari; Ohno, Akiko; Inaba, Yohei; Nakagome, Hideki; Kunugita, Naoki

2012-09-21

A typical method for the measurement of glutaraldehyde (GLA) employs 2,4-dinitrophenylhydrazine (DNPH) to form GLA-DNPhydrazone derivatives. However, this method is subject to analytical errors because GLA-DNPhydrazone is a quaternary bis-derivative and forms three geometric isomers (E-E, E-Z and Z-Z) as a result of the two C[double bond, length as m-dash]N double bonds. To overcome this issue, a method for transforming the C[double bond, length as m-dash]N double bond into a C-N single bond, using reductive amination of DNPhydrazone derivatives, has been applied. The amination reaction of GLA-DNPhydrazones with 2-picoline borane is accelerated with catalytic amounts of acid and is completed within 10 minutes in the presence of 100 mmol L(-1) phosphoric acid. Reduction of GLA-DNPhydrazone by 2-picoline borane is unique and results in the formation of N-(2,4-dinitrophenyl)-1-piperidinamine (DNPPA). NMR and LC-APCI-MS data confirmed the product identification. DNPPA is very stable and did not change when stored for at least four weeks at room temperature. DNPPA has excellent solubility of 14.6 g L(-1) at 20 °C in acetonitrile. The absorption maximum wavelength and the molar absorptivity of DNPPA were 351 nm and 4.2 × 10(4) L mol(-1) cm(-1) respectively. Complete separation between the reduced forms of C1-C10 aldehyde DNPhydrazones, including DNPPA, can be achieved by operating the reversed-phase high-performance liquid chromatograph at 351 nm in gradient mode using a C18 amide column. The reductive amination method for GLA overcomes analytical errors caused by E-E, E-Z and Z-Z geometrical isomers.

A validated high-performance liquid chromatographic method for the determination of glibenclamide in human plasma and its application to pharmacokinetic studies.

Science.gov (United States)

Niopas, Ioannis; Daftsios, Athanasios C

2002-05-15

Glibenclamide is a potent second generation oral sulfonylurea antidiabetic agent widely used for the treatment of type II diabetes melitus. A rapid, sensitive, precise, accurate and specific HPLC assay for the determination of glibenclamide in human plasma was developed and validated. After addition of flufenamic acid as internal standard, the analytes were isolated from human plasma by liquid-liquid extraction. The method was linear in the 10-400 ng/ml concentration range (r > 0.999). Recovery for glibenclamide was greater than 91.5% and for internal standard was 93.5%. Within-day and between-day precision, expressed as the relative standard deviation (RSD%), ranged from 1.4 to 5.9% and 5.8 to 6.6%, respectively. Assay accuracy was better than 93.4%. The assay was used to estimate the pharmacokinetics of glibenclamide after oral administration of a 5 mg tablet of glibenclamide to 18 healthy volunteers.

Comparison of twin-cell centrifugal partition chromatographic columns with different cell volume.

Science.gov (United States)

Goll, Johannes; Audo, Gregoire; Minceva, Mirjana

2015-08-07

Two twin-cell centrifugal partition chromatographic columns (SCPC 250 and SCPE-250-BIO, Armen Instrument, France) with the same column volume but different cell size and number were compared in terms of stationary phase retention and column efficiency. The columns were tested with two types of solvent systems: a commonly used organic solvent based biphasic system from the ARIZONA solvent system family and a polymer/salt based aqueous two phase system (ATPS). The efficiency of the columns was evaluated by pulse injection experiments of two benzenediols (pyrocatechol and hydroquinone) in the case of the ARIZONA system and a protein mixture (myoglobin and lysozyme) in the case of the ATPS. As result of high stationary phase retention, the column with the lower number of larger twin-cells (SCPE-250-BIO) is suitable for protein separations using ATPS. On the other hand, due to higher column efficiency, the column with the greater number of smaller cells (SCPC 250) is superior for batch elution separations performed with standard liquid-liquid chromatography organic solvent based biphasic systems. Copyright © 2015 Elsevier B.V. All rights reserved.

Gas-Chromatographic Determination Of Water In Freon PCA

Science.gov (United States)

Melton, Donald M.

1994-01-01

Gas-chromatographic apparatus measures small concentrations of water in specimens of Freon PCA. Testing by use of apparatus faster and provides greater protection against accidental contamination of specimens by water in testing environment. Automated for unattended operation. Also used to measure water contents of materials, other than Freon PCA. Innovation extended to development of purgeable sampling accessory for gas chromatographs.

Application of a rapid and sensitive liquid chromatography-tandem mass spectrometry method for determination of bumetanide in human plasma for a bioequivalence study.

Science.gov (United States)

Patel, Dinesh S; Sharma, Naveen; Patel, Mukesh C; Patel, Bhavin N; Shrivastav, Pranav S; Sanyal, Mallika

2012-07-01

A rapid, selective and sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) assay has been proposed for the determination of bumetanide in human plasma using tamsulosin as internal standard (IS). The analyte and IS were extracted from 200 μL of human plasma via solid phase extraction and the chromatographic separation was achieved on Peerless Basic C18 (100 mm × 4.6 mm, 3 μm) column under isocratic conditions. Detection of bumetanide and IS was done by tandem mass spectrometry, operating in positive ionization and multiple reaction monitoring (MRM) acquisition mode. The protonated precursor to product ion transitions monitored for bumetanide and IS were m/z 365.2→240.2 and 409.2→228.2 respectively. The method was fully validated as per the US FDA guidelines. The limit of detection and lower limit of quantitation of the method were 0.03 and 0.30 ng/mL respectively with a linear dynamic range of 0.30-200.0 ng/mL for bumetanide. The intra-batch and inter-batch precision (% CV) was ≤6.9% while the mean extraction recovery was >90% across quality control levels. The method is selective in presence of four diuretic drugs and some commonly used medications by healthy volunteers. It was successfully applied to a bioequivalence study of 2mg bumetanide tablet formulation in 10 healthy Indian male subjects under fasting condition. The reproducibility in the measurement of study data was demonstrated by reanalysis of 42 incurred samples. Copyright © 2012 Elsevier B.V. All rights reserved.

Reversed phase chromatographic behaviour of Pu (III), Pu (IV) and Pu (VI) in presence of α-hydroxyisobutyric acid

International Nuclear Information System (INIS)

Jaison, P.G.; Telmore, V.M.; Kumar, Pranaw

2016-01-01

Understanding the aqueous chemistry of plutonium is important in process conditions as well as in environmental conditions. Since plutonium possesses multiple oxidation states which can coexist in solution, a reliable method for the identification of these oxidation states is essential to understand its physical and chemical processes. The identification of plutonium oxidation states is conventionally determined through a series of liquid-liquid extraction procedures using selective extractants. Spectroscopic and laser based techniques also have been used for the identification of its oxidation state in solutions. Liquid chromatographic behavior of different oxidation states of Pu and other actinide ions is reported to correlate their retention behaviour with stability constants. Objective of the present work is to study the reversed phase chromatography behavior of the three oxidation states of plutonium viz. Pu(III), Pu(IV) and Pu(VI) in presence of á-hydroxyisobutyric acid (HIBA) as an eluent

Ultra-fast liquid chromatography with tandem mass spectrometry determination of ochratoxin A in traditional Chinese medicines based on vortex-assisted solid-liquid microextraction and aptamer-affinity column clean-up.

Science.gov (United States)

Yang, Xihui; Hu, Yichen; Kong, Weijun; Chu, Xianfeng; Yang, Meihua; Zhao, Ming; Ouyang, Zhen

2014-11-01

A rapid, selective, and sensitive ultra-fast liquid chromatography with tandem mass spectrometry method was developed for the determination of ochratoxin A in traditional Chinese medicines based on vortex-assisted solid-liquid microextraction and aptamer-affinity column clean-up. Through optimizing the sample pretreatment procedures and chromatographic conditions, good linearity (r(2) ≥ 0.9993), low limit of detection (0.5-0.8 μg/kg), and satisfactory recovery (83.54-94.44%) expressed the good reliability and applicability of the established method in various traditional Chinese medicines. Moreover, the aptamer-affinity column, prepared in-house, showed an excellent feasibility owing to its specific identification of ochratoxin A in various kinds of selected traditional Chinese medicines. The maximum adsorption amount and applicability value were 188.96 ± 10.56 ng and 72.3%, respectively. The matrix effects were effectively eliminated, especially for m/z 404.2→358.0 of ochratoxin A. The application of the developed method for screening the natural contamination levels of ochratoxin A in 25 random traditional Chinese medicines on the market in China indicated that only eight samples were contaminated with low levels below the legal limit (5.0 μg/kg) set by the European Union. This study provided a preferred choice for the rapid and accurate monitoring of ochratoxin A in complex matrices. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Selective micellar electrokinetic chromatographic method for simultaneous determination of some pharmaceutical binary mixtures containing non-steroidal anti-inflammatory drugs

Directory of Open Access Journals (Sweden)

Michael E. El-Kommos

2013-02-01

Full Text Available A simple and selective micellar electrokinetic chromatographic (MEKC method has been developed for the analysis of five pharmaceutical binary mixtures containing three non-steroidal anti-inflammatory drugs (NSAIDs. The investigated mixtures were Ibuprofen (IP–Paracetamol (PC, Ibuprofen (IP–Chlorzoxazone (CZ, Ibuprofen (IP–Methocarbamol (MC, Ketoprofen (KP–Chlorzoxazone (CZ and Diclofenac sodium (DS–Lidocaine hydrochloride (LC. The separation was run for all mixtures using borate buffer (20 mM, pH 9 containing 15% (v/v methanol and 100 mM sodium dodecyl sulphate (SDS at 15 kV and the components were detected at 214 nm. Different factors affecting the electrophoretic mobility of the seven investigated drugs were studied and optimized. The method was validated according to international conference of harmonization (ICH guidelines and United States pharmacopoeia (USP. The method was applied to the analysis of five pharmaceutical binary mixtures in their dosage forms. The results were compared with other reported high performance liquid chromatographic methods and no significant differences were observed. Keywords: Capillary electrophoresis, Micellar electrokinetic chromatographic method, Non-steroidal anti-inflammatory drugs, Pharmaceutical binary mixtures, Pharmaceutical analysis

Studies on Chromatographic Fingerprint and Fingerprinting Profile-Efficacy Relationship of Polygoni Perfoliati Herba

Directory of Open Access Journals (Sweden)

Li Tian

2013-01-01

Full Text Available Polygoni Perfoliati Herba is widely used in China with antibacterium, anti-inflammatory, expectorant, antitumor, and antivirus activities. To reveal the mechanisms of the activities of Polygoni Perfoliati Herba, the relationship between the fingerprinting profile and its bioactivities was investigated. In the present study, high-performance liquid chromatographic (HPLC fingerprinting method was developed. The established method was applied to analyze 51 batches of Polygoni Perfoliati Herba samples collected from different locations or in different harvesting times in China. Chemometrics, including similarity analysis, hierarchical clustering analysis, and principal component analysis, were used to express their similarities. It was found that similarity values of the samples were in the range of 0.432–0.998. The results of analgesic tests indicated that Polygoni Perfoliati Herba could significantly inhibit pain induced by hot plate and acetic acid in mice. The results of anti-inflammatory tests showed that Polygoni Perfoliati Herba had good anti-inflammatory effects (P < 0.01 in two models including dimethyl benzene-induced ear edema and acetic acid-induced peritoneal permeability in mice. Combining the results from chromatographic fingerprints with those from bioactivities, we found that seven peaks from Polygoni Perfoliati Herba were mainly responsible for analgesic and anti-inflammatory activities.

Rapid and automated determination of plutonium and neptunium in environmental samples

International Nuclear Information System (INIS)

Qiao, J.

2011-03-01

This thesis presents improved analytical methods for rapid and automated determination of plutonium and neptunium in environmental samples using sequential injection (SI) based chromatography and inductively coupled plasma mass spectrometry (ICP-MS). The progress of methodology development in this work consists of 5 subjects stated as follows: 1) Development and optimization of an SI-anion exchange chromatographic method for rapid determination of plutonium in environmental samples in combination of inductively coupled plasma mass spectrometry detection (Paper II); (2) Methodology development and optimization for rapid determination of plutonium in environmental samples using SI-extraction chromatography prior to inductively coupled plasma mass spectrometry (Paper III); (3) Development of an SI-chromatographic method for simultaneous determination of plutonium and neptunium in environmental samples (Paper IV); (4) Investigation of the suitability and applicability of 242 Pu as a tracer for rapid neptunium determination using anion exchange chromatography in an SI-network coupled with inductively coupled plasma mass spectrometry (Paper V); (5) Exploration of macro-porous anion exchange chromatography for rapid and simultaneous determination of plutonium and neptunium within an SI system (Paper VI). The results demonstrate that the developed methods in this study are reliable and efficient for accurate assays of trace levels of plutonium and neptunium as demanded in different situations including environmental risk monitoring and assessment, emergency preparedness and surveillance of contaminated areas. (Author)

Rapid and automated determination of plutonium and neptunium in environmental samples

Energy Technology Data Exchange (ETDEWEB)

Qiao, J.

2011-03-15

This thesis presents improved analytical methods for rapid and automated determination of plutonium and neptunium in environmental samples using sequential injection (SI) based chromatography and inductively coupled plasma mass spectrometry (ICP-MS). The progress of methodology development in this work consists of 5 subjects stated as follows: 1) Development and optimization of an SI-anion exchange chromatographic method for rapid determination of plutonium in environmental samples in combination of inductively coupled plasma mass spectrometry detection (Paper II); (2) Methodology development and optimization for rapid determination of plutonium in environmental samples using SI-extraction chromatography prior to inductively coupled plasma mass spectrometry (Paper III); (3) Development of an SI-chromatographic method for simultaneous determination of plutonium and neptunium in environmental samples (Paper IV); (4) Investigation of the suitability and applicability of 242Pu as a tracer for rapid neptunium determination using anion exchange chromatography in an SI-network coupled with inductively coupled plasma mass spectrometry (Paper V); (5) Exploration of macro-porous anion exchange chromatography for rapid and simultaneous determination of plutonium and neptunium within an SI system (Paper VI). The results demonstrate that the developed methods in this study are reliable and efficient for accurate assays of trace levels of plutonium and neptunium as demanded in different situations including environmental risk monitoring and assessment, emergency preparedness and surveillance of contaminated areas. (Author)

Liquid chromatography automatic system with optical activity laser detector and its applications

International Nuclear Information System (INIS)

Fajer, V.; Naranjo, S.; Fernandez, H.; Mora, W.; Cepero, T.; Arista, E.; Mesa, G.; Cossio, G.; Arreche, J.; Fonfria, C.; Rodriguez, C.W.

2009-01-01

A new liquid chromatographic system with polarimetric detection and a computer program allowing the output of chromatograms to a display on line and electronic data storing was designed, built and put to work. The chromatographic system includes the laser polarimetric detector, having a measuring interval of one second, the chromatographic columns, the continuous flux polarimeter tubes of 50 and 100 mm, the programs for data acquisition, processing and storing, and the technical know-how for its most efficiently application. Thirty minutes is all the time needed to obtain a chromatogram by this method which is reasonably shorter than the time required for any other known comparable technique, and offering, besides, lower operation cost. The combination of molecular exclusion liquid chromatography and laser polarimetric detection has turned into a carbohydrate separation and quantification system of basic importance for the evaluation of plants fluids of industrial interest (sugarcane, agave, vegetable extracts, etc.). It is described here the application of this system as an early or complementary indicator of leaf scald -disease that affects sugarcane plants-. Another application on algae extracts gave good results in the separation and identification of biologically active components. The introduction of this system in several research centers in Cuba and abroad has resulted in practical information for the industry. (Author)

DETECTION AND QUANTIFICATION OF PHYTOCHEMICAL MARKERS OF Ilex paraguariensis BY LIQUID CHROMATOGRAPHY

Directory of Open Access Journals (Sweden)

Rodrigo M. C. Pinto

2015-11-01

Full Text Available Ilex paraguariensis (yerba-mate is used as a beverage, and its extract requires adequate quality control methods in order to guarantee quality and safe use. Strategies to develop and optimize a chromatographic method to quantify theobromine, caffeine, and chlorogenic acid in I. paraguariensis extracts were evaluated by applying a quality by design (QbD model and ultra high-performance liquid chromatography (UHPLC. The presence of these three phytochemical markers in the extracts was evaluated using UHPLC-MS and was confirmed by the chromatographic bands in the total ion current traces (m/z of 181.1 [M+H]+, 195.0 [M+H]+, and 353.0 [M−H]−, respectively. The developed method was then transferred to a high-performance liquid chromatography (HPLC platform, and the three phytochemical markers were used as external standards in the validation of a method for analyses of these compounds in extracts using a diode array detector (DAD. The validated method was applied to quantify the chlorogenic acid, caffeine, and theobromine in the samples. HPLC-DAD chromatographic fingerprinting was also used in a multivariate approach to process the entire data and to separate the I. paraguariensis extracts into two groups. The developed method is very useful for qualifying and quantifying I. paraguariensis extracts.

Diffusion-stress coupling in liquid phase during rapid solidification of binary mixtures

International Nuclear Information System (INIS)

Sobolev, S.L.

2014-01-01

An analytical model has been developed to describe the diffusion-viscous stress coupling in the liquid phase during rapid solidification of binary mixtures. The model starts with a set of evolution equations for diffusion flux and viscous pressure tensor, based on extended irreversible thermodynamics. It has been demonstrated that the diffusion-stress coupling leads to non-Fickian diffusion effects in the liquid phase. With only diffusive dynamics, the model results in the nonlocal diffusion equations of parabolic type, which imply the transition to complete solute trapping only asymptotically at an infinite interface velocity. With the wavelike dynamics, the model leads to the nonlocal diffusion equations of hyperbolic type and describes the transition to complete solute trapping and diffusionless solidification at a finite interface velocity in accordance with experimental data and molecular dynamic simulation. -- Highlights: •We propose the diffusion-stress coupling model for binary solidification. •The coupling arises at deep undercooling. •With diffusive dynamics, the models result in parabolic transfer equations. •With the wavelike dynamics, the models lead to hyperbolic transfer equations. •The coupling strongly affects the solute partition coefficient

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.

Microwave-assisted ionic liquid-mediated rapid catalytic conversion of non-edible lignocellulosic Sunn hemp fibres to biofuels.

Science.gov (United States)

Paul, Souvik Kumar; Chakraborty, Saikat

2018-04-01

Sunn hemp fibre - a cellulose-rich crystalline non-food energy crop, containing 75.6% cellulose, 10.05% hemicellulose, 10.32% lignin, with high crystallinity (80.17%) and degree of polymerization (650) - is identified as a new non-food substrate for lignocellulosic biofuel production. Microwave irradiation is employed to rapidly rupture the cellulose's glycosidic bonds and enhance glucose yield to 78.7% at 160 °C in only 46 min. The reactants - long-chain cellulose, ionic liquid, transition metal catalyst, and water - form a polar supramolecular complex that rotates under the microwave's alternating polarity and rapidly dissipates the electromagnetic energy through molecular collisions, thus accelerating glycosidic bond breakage. In 46 min, 1 kg of Sunn hemp fibres containing 756 g of cellulose produces 595 g of glucose at 160 °C, and 203 g of hydroxymethyl furfural (furanic biofuel precursor) at 180 °C. Yeast mediated glucose fermentation produces 75.6% bioethanol yield at 30 °C, and the ionic liquid is recycled for cost-effectiveness. Copyright © 2018 Elsevier Ltd. All rights reserved.

Liquid chromatographic-tandem mass spectrometric determination of selected sulphonamides in milk

NARCIS (Netherlands)

Rhijn, van J.A.; Lasaroms, J.J.P.; Berendsen, B.J.A.; Brinkman, U.A.Th.

2002-01-01

Liquid chromatography–tandem mass spectrometry is used for the quantitative analysis of selected sulphonamides in milk. Ultrafiltration is the only sample pre-treatment technique which is required. Consequently, sample throughput is much higher than with conventional procedures, and analyte

In situ derivatization and hollow fiber membrane microextraction for gas chromatographic determination of haloacetic acids in water

Energy Technology Data Exchange (ETDEWEB)

Varanusupakul, Pakorn [Chromatography and Separation Research Unit, Department of Chemistry, Faculty of Science, Chulalongkorn University, Phayathai Road, Patumwan, Bangkok 10330 (Thailand)], E-mail: pakorn.v@chula.ac.th; Vora-adisak, Narongchai; Pulpoka, Bancha [Chromatography and Separation Research Unit, Department of Chemistry, Faculty of Science, Chulalongkorn University, Phayathai Road, Patumwan, Bangkok 10330 (Thailand)

2007-08-15

An alternative method for gas chromatographic determination of haloacetic acids (HAAs) in water using direct derivatization followed by hollow fiber membrane liquid-phase microextraction (HF-LPME) has been developed. The method has improved the sample preparation step according to the conventional US EPA Method 552.2 by combining the derivatization and the extraction into one step prior to determination by gas chromatography electron captured detector (GC-ECD). The HAAs were derivatized with acidic methanol into their methyl esters and simultaneously extracted with supported liquid hollow fiber membrane in headspace mode. The derivatization was attempted directly in water sample without sample evaporation. The HF-LPME was performed using 1-octanol as the extracting solvent at 55 deg. C for 60 min with 20% Na{sub 2}SO{sub 4}. The linear calibration curves were observed for the concentrations ranging from 1 to 300 {mu}g L{sup -1} with the correlation coefficients (R{sup 2}) being greater than 0.99. The method detection limits of most analytes were below 1 {mu}g L{sup -1} except DCAA and MCAA that were 2 and 18 {mu}g L{sup -1}, respectively. The recoveries from spiked concentration ranged from 97 to 109% with %R.S.D. less than 12%. The method was applied for determination of HAAs in drinking water and tap water samples. The method offers an easy one step high sample throughput sample preparation for gas chromatographic determination of haloacetic acids as well as other contaminants in water.

In situ derivatization and hollow fiber membrane microextraction for gas chromatographic determination of haloacetic acids in water

International Nuclear Information System (INIS)

Varanusupakul, Pakorn; Vora-adisak, Narongchai; Pulpoka, Bancha

2007-01-01

An alternative method for gas chromatographic determination of haloacetic acids (HAAs) in water using direct derivatization followed by hollow fiber membrane liquid-phase microextraction (HF-LPME) has been developed. The method has improved the sample preparation step according to the conventional US EPA Method 552.2 by combining the derivatization and the extraction into one step prior to determination by gas chromatography electron captured detector (GC-ECD). The HAAs were derivatized with acidic methanol into their methyl esters and simultaneously extracted with supported liquid hollow fiber membrane in headspace mode. The derivatization was attempted directly in water sample without sample evaporation. The HF-LPME was performed using 1-octanol as the extracting solvent at 55 deg. C for 60 min with 20% Na 2 SO 4 . The linear calibration curves were observed for the concentrations ranging from 1 to 300 μg L -1 with the correlation coefficients (R 2 ) being greater than 0.99. The method detection limits of most analytes were below 1 μg L -1 except DCAA and MCAA that were 2 and 18 μg L -1 , respectively. The recoveries from spiked concentration ranged from 97 to 109% with %R.S.D. less than 12%. The method was applied for determination of HAAs in drinking water and tap water samples. The method offers an easy one step high sample throughput sample preparation for gas chromatographic determination of haloacetic acids as well as other contaminants in water

Degradation of gas-liquid gliding arc discharge on Acid Orange II

International Nuclear Information System (INIS)

Yan, J.H.; Liu, Y.N.; Bo, Zh.; Li, X.D.; Cen, K.F.

2008-01-01

The effects of pH value, initial concentration of dye solution and temperature on the degradation efficiency of Acid Orange II (AO7) using gas-liquid gliding arc discharge were investigated. The influences of pH value and temperature on degradation efficiency were not apparent. Increasing initial solution concentration caused the decrease of degradation rate and the increase of absolute degradation quantity. Considering energy efficiency and absolute degradation quantity, the gas-liquid gliding arc discharge is fit for treating high concentration organic wastewater. A possible mineralization pathway was proposed through the analysis of intermediate products detected by gas chromatograph coupled with mass spectrophotometer (GC-MS) and ion chromatograph (IC). Hydroxyl radicals reacted with the azo linkage-bearing carbon of a hydroxy-substituted ring, leading to the cleavage of -C-N- and degradation of AO7. The solution biodegradability was significantly improved (BOD 5 /COD from 0.02 to 0.43). The toxicity of intermediate products was lower than that of the initial Acid Orange II

Quantitation of triacylglycerols in edible oils by off-line comprehensive two-dimensional liquid chromatography-atmospheric pressure chemical ionization mass spectrometry using a single column.

Science.gov (United States)

Wei, Fang; Hu, Na; Lv, Xin; Dong, Xu-Yan; Chen, Hong

2015-07-24

In this investigation, off-line comprehensive two-dimensional liquid chromatography-atmospheric pressure chemical ionization mass spectrometry using a single column has been applied for the identification and quantification of triacylglycerols in edible oils. A novel mixed-mode phenyl-hexyl chromatographic column was employed in this off-line two-dimensional separation system. The phenyl-hexyl column combined the features of traditional C18 and silver-ion columns, which could provide hydrophobic interactions with triacylglycerols under acetonitrile conditions and can offer π-π interactions with triacylglycerols under methanol conditions. When compared with traditional off-line comprehensive two-dimensional liquid chromatography employing two different chromatographic columns (C18 and silver-ion column) and using elution solvents comprised of two phases (reversed-phase/normal-phase) for triacylglycerols separation, the novel off-line comprehensive two-dimensional liquid chromatography using a single column can be achieved by simply altering the mobile phase between acetonitrile and methanol, which exhibited a much higher selectivity for the separation of triacylglycerols with great efficiency and rapid speed. In addition, an approach based on the use of response factor with atmospheric pressure chemical ionization mass spectrometry has been developed for triacylglycerols quantification. Due to the differences between saturated and unsaturated acyl chains, the use of response factors significantly improves the quantitation of triacylglycerols. This two-dimensional liquid chromatography-mass spectrometry system was successfully applied for the profiling of triacylglycerols in soybean oils, peanut oils and lord oils. A total of 68 triacylglycerols including 40 triacylglycerols in soybean oils, 50 triacylglycerols in peanut oils and 44 triacylglycerols in lord oils have been identified and quantified. The liquid chromatography-mass spectrometry data were analyzed

Chromatographic techniques used in the laboratory scale fractionation and purification of plasma

International Nuclear Information System (INIS)

Siti Najila Mohd Janib; Wan Hamirul Bahrin Wan Kamal; Shaharuddin Mohd

2004-01-01

Chromatography is a powerful technique used in the separation as well as purification of proteins for use as biopharmaceuticals or medicines. Scientists use many different chromatographic techniques in biotechnology as they bring a molecule from its initial identification stage to the stage of it becoming a marketed product. The most commonly used of these techniques is liquid chromatography (1,C). This technique can be used to separate the target molecule from undesired contaminants, as well as to analyse the final product for the requisite purity as established by governmental regulatory groups such as the FDA. Some examples of LC techniques include: ion exchange (IEC), hydrophobic interaction (HIC), gel filtration (GF), affinity (AC) and reverse phase (RPC) chromatography. These techniques are very versatile and can be used at any stage of the purification process i.e. capture, intermediate purification phase and polishing. The choice of a particular technique is dependent upon the nature of the target protein as well as its intended final use. This paper describes the preliminary work done on the chromatographic purification of factor VIII (FVIII), factor IX (FIX), albumin and IgG from plasma. Results, in particular, in the isolation of albumin and IgG using IEC, have been promising. Preparation and production of cryoprecipitate to yield FVIII and FIX have also been successful. (Author)

Applications of a post-column fluorigenic reaction in liquid chromatography for the determination of glucose and fructose in biological matrices

International Nuclear Information System (INIS)

Coquet, A.; Veuthey, J.-L.; Haerdi, W.; Degli Agosti, R.

1991-01-01

A post-column fluorigenic reaction with benzamidine coupled to liquid chromatographic separation was used for the determination of reducing carbohydrates in three complex biological samples. This method allows the simultaneous determination of the different reducing sugars, which represent an improvement over batch enzymatic tests where in most instances only single monosaccharides can be determined. This selective liquid chromatographic method has a broad linear range. The method was validated by simultaneous analyses with a specific enzymatic test for glucose. Results are presented for the determination of glucose in human serum and mustard plants and glucose and fructose in white wines. (author). 14 refs.; 3 figs.; 3 tabs

Determination of trace amounts of hydroperoxides by column liquid chromatography and colorimetric detection

NARCIS (Netherlands)

Deelder, R.S.; Kroll, M.; van den Berg, J.H.M.

1976-01-01

The sensitive and selective determination of separated compounds in effluents from liquid chromatographic columns can be carried out by continuously adding a suitable colorimetric agent to the column effluent and continuously monitoring the absorbance of the reaction mixture. However, a considerable

Determination of periplocymarin in human blood and urine by high-performance liquid chromatography-mass spectrometry

Directory of Open Access Journals (Sweden)

Chen Jian Xia

2017-01-01

Full Text Available A simple, rapid and sensitive liquid chromatography with tandem mass spectrometry method for the determination of periplocymarin in human blood and urine was developed. The digoxin-d3 was used as an internal standard. Periplocymarin and digoxin-d3 (IS were processed with ethyl acetate by liquid-liquid extraction. The chromatographic separation was performed on a Shim-pack XR-ODSIII C18 column with a 7 min gradient elution using methanol-ammonium formate (5 mmol/L as mobile phase at a flow rate of 0.3 mL/min (65:35, v/v. The detection was performed on a triple quadrupole tandem mass spectrometer using positive-ion mode electrospray ionization in selected reaction monitoring mode. The periplocymarin was well separated from the internal standard. Two calibration curves were linear within the concentration range 0.01-1 μg/mL. The limit of detection and quantification of blood and urine samples were both estimated at 0.005 and 0.01 μg/mL. The interday and intraday precisions, accuracy, and recovery were assessed to verify this method. The results showed that the method was suitable for the determination of periplocymarin in forensic toxicological analysis and clinical diagnosis.

Rapid and sensitive analysis of polychlorinated biphenyls and acrylamide in food samples using ionic liquid-based in situ dispersive liquid-liquid microextraction coupled to headspace gas chromatography.

Science.gov (United States)

Zhang, Cheng; Cagliero, Cecilia; Pierson, Stephen A; Anderson, Jared L

2017-01-20

A simple and rapid ionic liquid (IL)-based in situ dispersive liquid-liquid microextraction (DLLME) method was developed and coupled to headspace gas chromatography (HS-GC) employing electron capture (ECD) and mass spectrometry (MS) detection for the analysis of polychlorinated biphenyls (PCBs) and acrylamide at trace levels from milk and coffee samples. The chemical structures of the halide-based ILs were tailored by introducing various functional groups to the cations to evaluate the effect of different structural features on the extraction efficiency of the target analytes. Extraction parameters including the molar ratio of IL to metathesis reagent and IL mass were optimized. The effects of HS oven temperature and the HS sample vial volume on the analyte response were also evaluated. The optimized in situ DLLME method exhibited good analytical precision, good linearity, and provided detection limits down to the low ppt level for PCBs and the low ppb level for acrylamide in aqueous samples. The matrix-compatibility of the developed method was also established by quantifying acrylamide in brewed coffee samples. This method is much simpler and faster compared to previously reported GC-MS methods using solid-phase microextraction (SPME) for the extraction/preconcentration of PCBs and acrylamide from complex food samples. Copyright © 2016 Elsevier B.V. All rights reserved.

Profiling ABA metabolites in Nicotiana tabacum L. leaves by ultra-performance liquid chromatography-electrospray tandem mass spectrometry.

Science.gov (United States)

Turecková, Veronika; Novák, Ondrej; Strnad, Miroslav

2009-11-15

We have developed a simple method for extracting and purifying (+)-abscisic acid (ABA) and eight ABA metabolites--phaseic acid (PA), dihydrophaseic acid (DPA), neophaseic acid (neoPA), ABA-glucose ester (ABAGE), 7'-hydroxy-ABA (7'-OH-ABA), 9'-hydroxy-ABA (9'-OH-ABA), ABAaldehyde, and ABAalcohol--before analysis by a novel technique for these substances, ultra-performance liquid chromatography-electrospray ionisation tandem mass spectrometry (UPLC-ESI-MS/MS). The procedure includes addition of deuterium-labelled standards, extraction with methanol-water-acetic acid (10:89:1, v/v), simple purification by Oasis((R)) HLB cartridges, rapid chromatographic separation by UPLC, and sensitive, accurate quantification by MS/MS in multiple reaction monitoring modes. The detection limits of the technique ranged between 0.1 and 1 pmol for ABAGE and ABA acids in negative ion mode, and 0.01-0.50 pmol for ABAGE, ABAaldehyde, ABAalcohol and the methylated acids in positive ion mode. The fast liquid chromatographic separation and analysis of ABA and its eight measured derivatives by UPLC-ESI-MS/MS provide rapid, accurate and robust quantification of most of the substances, and the low detection limits allow small amounts of tissue (1-5mg) to be used in quantitative analysis. To demonstrate the potential of the technique, we isolated ABA and its metabolites from control and water-stressed tobacco leaf tissues then analysed them by UPLC-ESI-MS/MS. Only ABA, PA, DPA, neoPA, and ABAGE were detected in the samples. PA was the most abundant analyte (ca. 1000 pmol/g f.w.) in both the control and water-stressed tissues, followed by ABAGE and DPA, which were both present at levels ca. 5-fold lower. ABA levels were at least 100-fold lower than PA concentrations, but they increased following the water stress treatment, while ABAGE, PA, and DPA levels decreased. Overall, the technique offers substantial improvements over previously described methods, enabling the detailed, direct study of

Rapid Determination of Imatinib in Human Plasma by Liquid Chromatography-Tandem Mass Spectrometry: Application to a Pharmacokinetic Study

Energy Technology Data Exchange (ETDEWEB)

Yang, Jeong Soo; Cho, Eun Gi; Huh, Wooseong; Ko, Jaewook; Jung, Jin Ah; Lee, Sooyoun [Samsung Medical Center, Seoul (Korea, Republic of)

2013-08-15

A simple, fast and robust analytical method was developed to determine imatinib in human plasma using liquid chromatography-tandem mass spectrometry with electrospray ionization in the positive ion mode. Imatinib and labeled internal standard were extracted from plasma with a simple protein precipitation. The chromatographic separation was performed using an isocratic elution of mobile phase involving 5.0 mM ammonium formate in water -5.0 mM ammonium formate in methanol (30:70, v/v) over 3.0 min on reversed-stationary phase. The detection was performed using a triple-quadrupole tandem mass spectrometer in multiple-reaction monitoring mode. The developed method was validated with lower limit of quantification of 10 ng/mL. The calibration curve was linear over 10-2000 ng/mL (R{sup 2} > 0.99). The method validation parameters met the acceptance criteria. The spiked samples and standard solutions were stable under conditions for storage and handling. The reliable method was successfully applied to real sample analyses and thus a pharmacokinetic study in 27 healthy Korean male volunteers.

Multiple chromatographic fingerprinting and its application to the quality control of herbal medicines

International Nuclear Information System (INIS)

Fan Xiaohui; Cheng Yiyu; Ye Zhengliang; Lin Ruichao; Qian Zhongzhi

2006-01-01

Recently, chromatographic fingerprinting has become one of the most powerful approaches to quality control of herbal medicines. However, the performance of reported chromatographic fingerprinting constructed by single chromatogram sometimes turns out to be inadequate for complex herbal medicines, such as multi-herb botanical drug products. In this study, multiple chromatographic fingerprinting, which consists of more than one chromatographic fingerprint and represents the whole characteristics of chemical constitutions of the complex medicine, is proposed as a potential strategy in this complicated case. As a typical example, a binary chromatographic fingerprinting of 'Danshen Dropping Pill' (DSDP), the best-sold traditional Chinese medicine in China, was developed. First, two HPLC fingerprints that, respectively, represent chemical characteristics of depsides and saponins of DSDP were developed, which were used to construct binary chromatographic fingerprints of DSDP. Moreover, the authentication and validation of the binary fingerprints were performed. Then, a data-level information fusion method was employed to capture the chemical information encoded in two chromatographic fingerprints. Based on the fusion results, the lot-to-lot consistency and frauds can be determined either using similarity measure or by chemometrics approach. The application of binary chromatographic fingerprinting to consistency assessment and frauds detection of DSDP clearly demonstrated that the proposed method was a powerful approach to quality control of complex herbal medicines

Fundulus heteroclitus gonadotropins.5: Small scale chromatographic fractionation of pituitary extracts into components with different steroidogenic activities using homologous bioassays

Directory of Open Access Journals (Sweden)

Petrino Teresa R

2004-03-01

Full Text Available Abstract Fractionation and characterization of gonadotropins (GtH from Fundulus heteroclitus pituitary extracts were carried out using a biocompatible liquid chromatographic procedure (Pharmacia FPLC system. Chromatographic fractions were monitored for gonadotropic activities (induction of oocyte maturation and steroid production using homologous follicle bioassays in vitro. Size-exclusion chromatography eluted gonadotropic activity in one major protein peak (Mr ~ 30,000. Anion-exchange and hydrophobic-interaction chromatography (HIC yielded two distinct peaks of 17beta-estradiol (E2- and 17alpha-hydroxy,20beta-dihydroprogesterone (DHP-promoting activity with associated oocyte maturation. Two-dimensional chromatography (chromatofocusing followed by HIC resolved pituitary extracts into two active fractions; both induced E2 synthesis, but one was relatively poor in eliciting DHP and testosterone production. Thus, using homologous bioassays, at least two quantitatively different gonadotropic (steroidogenic activities: an E2-promoting gonadotropin (GtH I-like and a DHP-promoting gonadotropin (GtH II-like, which has a lower isoelectric point but greater hydrophobicity than the former, can be distinguished from F. heteroclitus pituitaries by a variety of chromatographic procedures. This study complements previous biochemical and molecular data in F. heteroclitus and substantiates the duality of GtH function in a multiple-spawning teleost.

Combined liquid chromatography-mass spectrometry for trace analysis of pharmaceuticals

International Nuclear Information System (INIS)

Schmidt, L.; Danigel, H.; Jungclas, H.

1982-01-01

A 252 Cf-plasma desorption mass spectrometer (PDMS) for the analysis of thin layers from nonvolatile organic samples has been set up to be combined with a liquid chromatograph. A novel interface performs the direct inlet of the liquid sample through a capillary into the vacuum system of the spectrometer. Samples of drugs are periodically collected, transferred to the ion source and analysed using a rotating disk. This on-line sample preparation has been tested for three antiarrhythmic drugs using various solvents and mixtures. (orig.)

Chromatographic separation of low-temperature tar. Part III

Energy Technology Data Exchange (ETDEWEB)

Terres, E; Gebert, F; Huelsemann, H; Petereit, H; Toepsch, H; Ruppert, W

1955-01-01

Experiments with crude phenolic mixtures in benzene-MeOH over an alumina chromatographic column are reported. The most effective separation into crude fractions was obtained from a petroleum-ether solution with benzene and benzene-MeOH elution. These fractions are analyzed by paper chromatography. R/sub f/ values for 29 phenols and benzoic acid from water-saturated AmOH are given. Folin-Denis reagent and ultraviolet absorption is used for identification of the phenolic compounds. R/sub f/ values for monohydroxy compounds are larger than 0.9, dihydroxy 0.80 to 0.9, trihydroxy 0.6, hydroxytoluic acids 0.39 to 0.56. R/sub f/ values of Na and K salts are different from those of the free phenols. Tests in aqueous solution near 0/sup 0/ gave important results. R/sub f/ values of the less polar materials decrease and less material is lost through evaporation, smaller and sharper spots are obtained and liquids move at a more even rate. A series of isomeric alkyl phenols is reported; ortho alkyl groups decrease the migration rate most effectively.

Separation of deuteriated isotopomers of dopamine by ion-pair reversed-phase high-performance liquid chromatography

International Nuclear Information System (INIS)

Masters, C.F.; Markey, S.P.; Mefford, I.N.; Duncan, M.W.

1988-01-01

The ion-pair reversed-phase separation of dopamine and deuterium-substituted dopamine isotopomers is described. Chromatographic parameters and deuterium isotope effects governing the resolution are examined and compared to the factors regulating the resolution are examined and compared to the factors regulating the resolution of the chemically distinct entities dopamine, norepinephrine, and epinephrine. The potential utility of the [ 2 H 7 ]dopamine, isotopomer as an internal standard for the high-performance liquid chromatography analysis of dopamine is demonstrated by using aluminum oxide extraction prior to chromatographic separation

Headspace gas chromatographic method for the measurement of difluoroethane in blood.

Science.gov (United States)

Broussard, L A; Broussard, A; Pittman, T; Lafferty, D; Presley, L

2001-01-01

To develop a gas chromatographic assay for the analysis of difluoroethane, a volatile substance, in blood and to determine assay characteristics including linearity, limit of quantitation, precision, and specificity. Referral toxicology laboratory Difluoroethane, a colorless, odorless, highly flammable gas used as a refrigerant blend component and aerosol propellant, may be abused via inhalation. A headspace gas chromatographic procedure for the identification and quantitation of difluoroethane in blood is presented. A methanolic stock standard prepared from pure gaseous difluoroethane was used to prepare whole blood calibrators. Quantitation of difluoroethane was performed using a six-point calibration curve and an internal standard of 1-propanol. The assay is linear from 0 to 115 mg/L including a low calibrator at 4 mg/L, the limit of quantitation. Within-run coefficients of variation at mean concentrations of 13.8 mg/L and 38.5 mg/L were 5.8% and 6.8% respectively. Between-run coefficients of variation at mean concentrations of 15.9 mg/L and 45.7 mg/L were 13.4% and 9.8% respectively. Several volatile substances were tested as potential interfering compounds with propane having a retention time identical to that of difluoroethane. This method requires minimal sample preparation, is rapid and reproducible, can be modified for the quantitation of other volatiles, and could be automated using an automatic sampler/injector system.

Isocratic Solid Phase Extraction-Liquid Chromatography (SPE-LC) Interfaced to High-Performance Tandem Mass Spectrometry for Rapid Protein Identification

DEFF Research Database (Denmark)

Hørning, Ole B; Kjeldsen, Frank; Theodorsen, Søren

2008-01-01

the isocratic solid phase extraction-liquid chromatography (SPE-LC) technology for rapid separation ( approximately 8 min) of simple peptide samples. We now extend these studies to demonstrate the potential of SPE-LC separation in combination with a hybrid linear ion trap-Orbitrap tandem mass spectrometer...

Determination of paraffins in food simulants and packaging materials by liquid chromatography with evaporative mass detection and identification of paraffin type by liquid chromatography/gas chromatography and fourier transform infrared spectroscopy

NARCIS (Netherlands)

Simal-Gándara, J.; Sarria-Vidal, M.; Rijk, M.A.H.

2000-01-01

A liquid chromatographic method with evaporative mass detection (EMD) is described for the determination of paraffins in food contact materials that do not contain polyolefin oligomers, or paraffins migrating from these materials into fatty food simulants or certain simple foods. A normal-phase

Chromatographic Methods for the Analysis of Polyphenols in Wines

Directory of Open Access Journals (Sweden)

Medić-Šarić, M.

2009-03-01

Full Text Available Wine is an excellent source of various classes of polyphenols, including phenolic acids, flavonoids, and trihydroxystilbene resveratrol (Fig.1. Polyphenols play a major role in wine quality since they contribute to the sensory characteristics of wine, particularly color and astringency. A recent interest in these substances has been stimulated by abundant evidence of their beneficial effects on human health, such as anticarcinogenic, antiinflamatory and antimicrobial activities. Therefore, numerous studies have been performed in the attempt to analyze polyphenols in wine. This paper reviews the current advances in the determination of polyphenols in wine by the major chromatographic techniques such as thin-layer chromatography (TLC and high-performance liquid chromatography (HPLC.The great complexity of the polyphenolic content of wine and the difficulty in obtaining some of the standards usually require sample preparation before analysis. Two methods for sample preparation, liquid-liquid extraction and solid-phase extraction, are most commonly applied. Hydrolysis is applied frequently, but not exclusively, to remove the sugar moieties from glycosides.TLC on silica gel plates is useful for the rapid and low-cost separation and identification of the polyphenols present in wine (Fig. 2. Densitometric quantitative analysis of polyphenols in wine extracts is usually performed by scanning the TLC plates with UV light at wavelengths of 350–365 nm or 250–260 nm (Fig. 3. For the evaluation of the most efficient mobile phase and an optimal choice of the combination of two or more mobile phases, two methods may be applied: information theory and numerical taxonomy. HPLC currently represents the most popular technique for the analysis of polyphenols in wine. For this purpose, a reversed-phase HPLC method that uses gradient elution with binary elution system is usually employed. Routine detection is based on measurement of UV-Vis absorption with a diode

Centrifuge-less dispersive liquid-liquid microextraction base on the solidification of switchable solvent for rapid on-site extraction of four pyrethroid insecticides in water samples.

Science.gov (United States)

Hu, Lu; Wang, Huazi; Qian, Heng; Liu, Chaoran; Lu, Runhua; Zhang, Sanbing; Zhou, Wenfeng; Gao, Haixiang; Xu, Donghui

2016-11-11

An on-site dispersive liquid liquid microextraction base on the solidification of switchable solvent has been developed as a simple, rapid and eco-friendly sample extraction method for the fast determination of pyrethroid insecticides in aqueous samples using high-performance liquid chromatography with ultraviolet detection. In this extraction method, medium-chain saturated fatty acids (n≥10), which can rapidly solidify at low temperatures (centrifugation. The microextraction process was performed in a 10mL syringe and the pretreatment process could thus be finished in 5min. No external energy resources were required in this method, which makes it a potential method for on-site extraction. The optimal experimental parameters were as follows: 350μL of decanoic acid (1mol/L) was used as the extraction solvent, 150μL of sulfuric acid (2mol/L) was used to decrease the pH of the samples, no salt was added, and the temperature of the samples was in the range of 20-40°C. Finally, the sample was cooled in an ice bath for three minutes. Under these optimal conditions, good responses for four pyrethroid insecticides were obtained in the concentration ranges of 1-500μg/L, with coefficients of determination greater than 0.9993. The recoveries of the four pyrethroid insecticides ranged from 84.7 to 95.3%, with relative standard deviations ranging from 1.6 to 4.6%. The limits of detection based on a signal-to-noise ratio of 3 were in the range of 0.24-0.68μg/L, and the enrichment factors were in the range of 121-136. The results demonstrate that this method was successfully applied to determine pyrethroid insecticides in real water samples. No centrifugation or any special apparatus are required, make this a promising method for rapid field-sampling procedures. Copyright © 2016 Elsevier B.V. All rights reserved.

Simple and Rapid Dual-Dispersive Liquid-Liquid Microextraction as an Innovative Extraction Method for Uranium in Real Water Samples Prior to the Determination of Uranium by a Spectrophotometric Technique.

Science.gov (United States)

Khan, Naeemullah; Tuzen, Mustafa; Kazi, Tasneem Gul

2017-11-01

An innovative, rapid, and simple dual-dispersive liquid-liquid microextraction (DDLL-ME) approach was used to extract uranium from real samples for the first time. The main objective of this study was to disperse extraction solvent by using an air-agitated syringe system to overcome matrix effects and avoid dispersion of hazardous dispersive organic solvents by using heat. The DDLL-ME method consisted of two dispersive liquid-liquid extraction steps with chloroform as the extracting solvent. Uranium formed complexes with 4-(2-thiazolylazo) resorcinol in the aqueous phase and was extracted in extracting solvent (chloroform) after the first dispersive liquid-liquid process. Uranium was then back-extracted in the acidic aqueous phase in a second dispersive liquid-liquid process. Finally, uranium was determined by a spectrophotometric detection technique. The variables that played a key role in the proposed method were studied and optimized. The LOD and sensitivity enhancement factor for uranium were found to be 0.60 µg/L and 45, respectively, under optimized conditions. Calibration graphs were found to be linear in the range of 5.0-600 µg/L. The RSD was 2.5%. Reliability of the proposed method was verified by analyzing certified reference material TM-28.3.

Evaluation of Flow-Injection Tandem Mass Spectrometry for Rapid and High-Throughput Quantitative Determination of B-Vitamins in Nutritional Supplements

Energy Technology Data Exchange (ETDEWEB)

Bhandari, Deepak [ORNL; Van Berkel, Gary J [ORNL

2012-01-01

The use of flow-injection electrospray ionization tandem mass spectrometry for rapid and high-throughput mass spectral analysis of selected B-vitamins, viz. B1, B2, B3, B5, and B6, in nutritional formulations was demonstrated. A simple and rapid (~5 min) in-tube sample preparation was performed by adding extraction solvent to a powdered sample aliquot followed by agitation, centrifugation, and filtration to recover an extract for analysis. Automated flow injection introduced 1 L of the extracts directly into the mass spectrometer ion source without chromatographic separation. Sample-to-sample analysis time was 60 s representing significant improvement over conventional liquid chromatography approaches which typically require 25-45 min, and often require more significant sample preparation procedures. Quantitative capabilities of the flow-injection analysis were tested using the method of standard additions and NIST standard reference material (SRM 3280) multivitamin/multielement tablets. The quantity determined for each B-vitamin in SRM 3280 was within the statistical range provided for the respective certified values. The same sample preparation and analysis approach was also applied to two different commercial vitamin supplement tablets and proved to be successful in the quantification of the selected B-vitamins as evidenced by an agreement with the labels values and the results obtained using isotope dilution liquid chromatography/mass spectrometry.

Multielement determination of rare earth elements by liquid chromatography/inductively coupled plasma atomic emission spectrometry

International Nuclear Information System (INIS)

Sawatari, Hideyuki; Asano, Takaaki; Hu, Xincheng; Saizuka, Tomoo; Itoh, Akihide; Hirose, Akio; Haraguchi, Hiroki

1995-01-01

The rapid determination of rare earth elements (REEs) has been investigated by an on-line system of high performance liquid chromatography/multichannel inductively coupled plasma atomic emission spectrometry. In the present system, all REEs could be detected simultaneously in a single chromatographic measurement without spectral interferences. Utilizing a cation exchange column and 2-hydroxy-2-methylpropanoic acid aqueous solution as the mobile phase, the detection limits of 0.4-30 ng ml -1 for all REEs were obtained. The system was applied to the determination of REEs in geological standard rock samples and rare earth impurities in high purity rare earth oxides. The REEs in standard rocks could be determined by the present HPLC/ICP-AES system without pretreatment after acid digestion, although the detection limits were not sufficient for the analysis of rare earth oxides. (author)

Chromatographic behavior of small organic compounds in low-temperature high-performance liquid chromatography using liquid carbon dioxide as the mobile phase.

Science.gov (United States)

Motono, Tomohiro; Nagai, Takashi; Kitagawa, Shinya; Ohtani, Hajime

2015-07-01

Low-temperature high-performance liquid chromatography, in which a loop injector, column, and detection cell were refrigerated at -35ºC, using liquid carbon dioxide as the mobile phase was developed. Small organic compounds (polyaromatic hydrocarbons, alkylbenzenes, and quinones) were separated by low-temperature high-performance liquid chromatography at temperatures from -35 to -5ºC. The combination of liquid carbon dioxide mobile phase with an octadecyl-silica (C18 ) column provided reversed phase mode separation, and a bare silica-gel column resulted in normal phase mode separation. In both the cases, nonlinear behavior at approximately -15ºC was found in the relationship between the temperature and the retention factors of the analytes (van't Hoff plots). In contrast to general trends in high-performance liquid chromatography, the decrease in temperature enhanced the separation efficiency of both the columns. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Multiple chromatographic fingerprinting and its application to the quality control of herbal medicines

Energy Technology Data Exchange (ETDEWEB)

Fan Xiaohui [Pharmaceutical Informatics Institute, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310027 (China); Cheng Yiyu [Pharmaceutical Informatics Institute, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310027 (China)]. E-mail: chengyy@zju.edu.cn; Ye Zhengliang [Pharmaceutical Informatics Institute, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310027 (China); Lin Ruichao [National Institute for the Control of Pharmaceutical and Biological Products, Beijing 100050 (China); Qian Zhongzhi [Committee of Chinese Pharmacopoeia, Beijing 100061 (China)

2006-01-12

Recently, chromatographic fingerprinting has become one of the most powerful approaches to quality control of herbal medicines. However, the performance of reported chromatographic fingerprinting constructed by single chromatogram sometimes turns out to be inadequate for complex herbal medicines, such as multi-herb botanical drug products. In this study, multiple chromatographic fingerprinting, which consists of more than one chromatographic fingerprint and represents the whole characteristics of chemical constitutions of the complex medicine, is proposed as a potential strategy in this complicated case. As a typical example, a binary chromatographic fingerprinting of 'Danshen Dropping Pill' (DSDP), the best-sold traditional Chinese medicine in China, was developed. First, two HPLC fingerprints that, respectively, represent chemical characteristics of depsides and saponins of DSDP were developed, which were used to construct binary chromatographic fingerprints of DSDP. Moreover, the authentication and validation of the binary fingerprints were performed. Then, a data-level information fusion method was employed to capture the chemical information encoded in two chromatographic fingerprints. Based on the fusion results, the lot-to-lot consistency and frauds can be determined either using similarity measure or by chemometrics approach. The application of binary chromatographic fingerprinting to consistency assessment and frauds detection of DSDP clearly demonstrated that the proposed method was a powerful approach to quality control of complex herbal medicines.

Rapid and sensitive liquid chromatography–tandem mass spectrometric method for the quantitative determination of potentially harmful substance 5,5′-oxydimethylenebis (2-furfural in traditional Chinese medicine injections

Directory of Open Access Journals (Sweden)

Qingce Zang

2018-03-01

Full Text Available With the rapid development and wide application of traditional Chinese medicine injection (TCMI, a number of adverse events of some TCMIs have incessantly been reported and have drawn broad attention in recent years. Establishing effective and practical analytical methods for safety evaluation and quality control of TCMI can help to improve the safety of TCMIs in clinical applications. In this study, a sensitive and rapid high-performance liquid chromatography–tandem mass spectrometry (HPLC–MS/MS method has been developed and validated for the quantitative determination of potentially harmful substance 5,5′-oxydimethylenebis (2-furfural, OMBF in TCMI samples. Chromatographic separation was performed on a C18 reversed-phase column (150 mm × 2.1 mm, 5 µm by gradient elution, using methanol–water containing 0.1% formic acid as mobile phase at the flow rate of 0.3 mL/min. MS/MS detection was performed on a triple quadrupole mass spectrometer with positive electrospray ionization in the multiple reaction-monitoring mode. The method was sensitive with a limit of quantification of 0.3 ng/mL and linear over the range of 0.3–30 ng/mL (r=0.9998. Intra- and inter-day precision for analyte was <9.52% RSD with recoveries in the range 88.0–109.67% at three concentration levels. The validated method was successfully applied to quantitatively determine the compound OMBF in TCMIs and glucose injections. Our study indicates that this method is simple, sensitive, practicable and reliable, and could be applied for safety evaluation and quality control of TCMIs and glucose injections. KEY WORDS: 5,5′-Oxydimethylenebis (2-furfural, LC–MS/MS, Quantitative analytical method, Traditional Chinese medicine injection, Quality control

The Liquid State

Indian Academy of Sciences (India)

like iron, aluminium, lead, zinc, etc .. Metals are cast ... dropping molten liquid of the alloys on a rapidly spinning copper wheel. ... Ed. Computer simulation studies in ... liquids, modelling ofliquids and study of the dynamic behaviour of liquids ...

Rapid and accurate determination of radiochemical purity of sup(99m)Tc compounds

International Nuclear Information System (INIS)

Tamat, S.R.

1977-01-01

The wide spread use of sup(99m)Tc-labelled radiopharmaceuticals and limitation of the short half-life of the isotope, is associated with an urgent need for a rapid, simple but accurate method for determining the radiochemical purity of the compound. A short paper chromatographic (KK) or thin layer chromatographic (KLT) method using 95% methanol or 0.9% saline solution as solvents, has solved the problem. With these methods, the amount of free sup(99m)Tc pertechnetate in a compound, can be determined in only a few minutes. These methods compare satisfactorily with lengtheir procedures. (author)

Temperature Control of Gas Chromatograph Based on Switched Delayed System Techniques

Directory of Open Access Journals (Sweden)

Xiao-Liang Wang

2014-01-01

Full Text Available We address the temperature control problem of the gas chromatograph. We model the temperature control system of the gas chromatograph into a switched delayed system and analyze the stability by common Lyapunov functional technique. The PI controller parameters can be given based on the proposed linear matrix inequalities (LMIs condition and the designed controller can make the temperature of gas chromatograph track the reference signal asymptotically. An experiment is given to illustrate the effectiveness of the stability criterion.

Simple and rapid method on High Performance Liquid Chromatography for simultaneous determination of benzylpenicillin potassium, streptomycin sulphate and related substances in Ascomicin – a veterinary use ointment

Directory of Open Access Journals (Sweden)

Neagu Maria

2015-06-01

Full Text Available A new simple, rapid, accurate and precise High – Performance Liquid Chromatography (HPLC method for determination of benzylpenicillin potassium and streptomycin sulphate in Ascomicin ointment was developed and validated. The method can be used for the detection and quantification of known and unknown impurities and degradation products in this pharmaceutical product during routine analysis and also for stability studies in view of its capability to separate degradation products. The method was validated for accuracy, precision, specificity, robustness and quantification limits according to ICH Guidelines. The estimation of benzylpenicillin potassium and streptomycin sulphate was done by Waters HPLC 2695. The chromatographic conditions comprised a reverse-phased C18 column (5 µm particle size, 250 mm×4.6 mm i.d. with a mobile phase consisting of a mixture of solution in water containing 0.025 M of sodium phosphate dibasic and 0.02 of sodium hexansulfonate adjusted to pH 6.0 with 22.5 g/lsolution of phosphoric acid and acetonitrile in gradient elution. The flow rate was 0.8 ml/min. Standard curves were linear over the concentration range of 5.00 µg/ml to 5.00 mg/ml for streptomycin sulphate and 3.26 µg/ml to 3.26 mg/ml for benzylpenicillin potassium. Statistical analyses proved the method was precise, reproducible, selective, specific and accurate for analysis of benzylpenicillin potassium, streptomycin sulphate and related substances.

Fractionation of fecal neutral steroids by high performance liquid chromatography

International Nuclear Information System (INIS)

Jackson, E.M.; Kloss, C.A.; Weintraub, S.T.; Mott, G.E.

1985-01-01

Fecal neutral steroids were fractionated by high performance liquid chromatography (HPLC) into three major fractions: 5 beta-H, 3-keto steroids; 5 beta-H, 3 beta-hydroxy steroids; and 5 alpha-H and delta 5-3 beta-hydroxy steroids. This separation was achieved in about 10 minutes, with greater than 97% recovery of standards in each fraction. Gas-liquid chromatographic quantitation of fecal steroids fractionated by either HPLC or thin-layer chromatography gave nearly identical results. A method using both C18 reverse phase and silica HPLC to purify radiolabeled sterols is also described

Extraction chromatographic method of uranium(VI) with high molecular mass amine (ALIQUAT - 336)

International Nuclear Information System (INIS)

Roy, Uday Sankar; Dutta, Keshab Kumar

1999-01-01

A selective method has been developed for reversed phase extraction chromatographic studies of uranium(VI) with Aliquat - 336 (liquid anion exchanger) coated on silica gel as stationary phase. Quantitative extraction of uranium has been achieved in HCl - medium from 1.25(M)-4(M). The effect of different acids with various concentrations stripping agents, flow rate on extraction and elution have been investigated. The exchange capacity of the prepared exchanger has been determined. Uranium(VI) has been separated quantitatively from Th, Ce, Zr, Pb, Ga, Hg, Fe, La, Pr, Nd, Sm and Cr from a binary mixture by controlling the extraction and elution conditions. The separation of U(VI) from ternary and quarternary mixtures of various metal ions has also been achieved. (author)

Stability-indicating liquid Chromatographic assaymethod for Opthalmic solutions containing combination of Dexamethasone and Chloramphenicol

International Nuclear Information System (INIS)

Rao, R.M.; Al-Ashban, R.M.; Shah, A.H.

2004-01-01

A selective high-performance chromatographic procedure for the stability monitoring of ophthalmic solutions containing a combination of dexamethasone and chloramphenicolis demonstrated. The separation of the active components and the degradation product of chloramphenicol (1-amino-1-(4-nitrophenyl)-propane-1, 3diol) was achieved on a u-Bondapack C-18 column ( 5 um, 300 mm x 3.9 mm) maintained at ambient temperature (15-20C) by utilizing a mobile phase consisting acidified water (5% actified water with glacial acetic acid ) : acetonitrile : triethyl amine 700 : 300 : 2and pH was adjusted to 5.0 by using 10 M Na OH. The flow rate was 1.5 ml min-1; and elutes were followed with UV-detection at 254 nm. Complete resolution of dexamethasone, chloramphenicol and its hydrolytic product could be attained. The sensitivity, accuracy and specificity were tested. The method was successfully applied in post-marketing stability of the commercial batches of ophthalmic solutions. (author)

Incorporation of metal-organic framework HKUST-1 into porous polymer monolithic capillary columns to enhance the chromatographic separation of small molecules.

Science.gov (United States)

Yang, Shengchao; Ye, Fanggui; Lv, Qinghui; Zhang, Cong; Shen, Shufen; Zhao, Shulin

2014-09-19

Metal-organic framework (MOF) HKUST-1 nanoparticles have been incorporated into poly(glycidyl methacrylate-co-ethylene dimethacrylate) (HKUST-1-poly(GMA-co-EDMA)) monoliths to afford stationary phases with enhanced chromatographic performance of small molecules in the reversed phase capillary liquid chromatography. The effect of HKUST-1 nanoparticles in the polymerization mixture on the performance of the monolithic column was explored in detail. While the bare poly(GMA-co-EDMA) monolith exhibited poor resolution (RsHKUST-1 nanoparticles to the polymerization mixture provide high increased resolution (Rs≥1.3) and high efficiency ranged from 16,300 to 44,300plates/m. Chromatographic performance of HKUST-1-poly(GMA-co-EDMA) monolith was demonstrated by separation of various analytes including polycyclic aromatic hydrocarbons, ethylbenzene and styrene, phenols and aromatic acids using a binary polar mobile phase (CH3CN/H2O). The HKUST-1-poly(GMA-co-EDMA) monolith displayed enhanced hydrophobic and π-π interaction characteristics in the reversed phase separation of test analytes compared to the bare poly(GMA-co-EDMA) monolith. The experiment results showed that HKUST-1-poly(GMA-co-EDMA) monoliths are an alternative to enhance the chromatographic separation of small molecules. Copyright © 2014 Elsevier B.V. All rights reserved.

Pre-column derivatisation method for the measurement of glycosylated hydroxylysines of collagenous proteins

NARCIS (Netherlands)

Bank, R.A.; Beekman, B.; Tenni, R.; Tekoppele, J.M.

1997-01-01

Measurement of the glycosylated hydroxylysines galactosyl- and glucosylgalactosylhydroxylysine (GH and GGH) in combination with other amino acids has been based on ion-exchange chromatography followed by reaction with ninhydrin. Here, a rapid and sensitive high-performance liquid chromatographic

Pesticide extraction from table grapes and plums using ionic liquid based dispersive liquid-liquid microextraction.

Science.gov (United States)

Ravelo-Pérez, Lidia M; Hernández-Borges, Javier; Herrera-Herrera, Antonio V; Rodríguez-Delgado, Miguel Angel

2009-12-01

Room temperature ionic liquids (RTILs) have been used as extraction solvents in dispersive liquid-liquid microextraction (DLLME) for the determination of eight multi-class pesticides (i.e. thiophanate-methyl, carbofuran, carbaryl, tebuconazole, iprodione, oxyfluorfen, hexythiazox, and fenazaquin) in table grapes and plums. The developed method involves the combination of DLLME and high-performance liquid chromatography with diode array detection. Samples were first homogenized and extracted with acetonitrile. After evaporation and reconstitution of the extract in water containing sodium chloride, a quick DLLME procedure that used the ionic liquid 1-hexyl-3-methylimidazolium hexafluorophosphate ([C(6)MIM][PF(6)]) and methanol was developed. The RTIL dissolved in a very small volume of acetonitrile was directed injected in the chromatographic system. The comparison between the calibration curves obtained from standards and from spiked sample extracts (matrix-matched calibration) showed the existence of a strong matrix effect for most of the analyzed pesticides. A recovery study was also developed with five consecutive extractions of the two types of fruits spiked at three concentration levels. Mean recovery values were in the range of 72-100% for table grapes and 66-105% for plum samples (except for thiophanate-methyl and carbofuran, which were 64-75% and 58-66%, respectively). Limits of detection (LODs) were in the range 0.651-5.44 microg/kg for table grapes and 0.902-6.33 microg/kg for plums, representing LODs below the maximum residue limits (MRLs) established by the European Union in these fruits. The potential of the method was demonstrated by analyzing 12 commercial fruit samples (six of each type).

High-performance liquid chromatographic method for the determination of dansyl-polyamines

Science.gov (United States)

Subhash C. Minocha; Rakesh Minocha; Cheryl A. Robie

1990-01-01

This paper describes a fast reliable, and a sensitive technique for the separation and quantification of dansylated polyamines by high-performance liquid chromatography. Using a small 33 x 4.6 mm I.D., 3 ?m particle size, C18 reversed-phase cartridge column and a linear gradient of acetonitrile-heptanesulfonate (10 mM, pH 3.4...

Subcritical thermal convection of liquid metals in a rapidly rotating sphere

Science.gov (United States)

Cardin, P.; Schaeffer, N.; Guervilly, C.; Kaplan, E.

2017-12-01

Planetary cores consist of liquid metals (low Prandtl number Pr) that convect as the core cools. Here we study nonlinear convection in a rotating (low Ekman number Ek) planetary core using a fully 3D direct (down to Ek=10-7) and a quasi geostrophic (down to Ek=10-10) numerical simulations. Near the critical thermal forcing (Rayleigh number Ra), convection onsets as thermal Rossby waves, but as Ra increases, this state is superceded by one dominated by advection. At moderate rotation, these states (here called the weak branch and strong branch, respectively) are continuously connected. As the planetary core rotates faster, the continuous transition is replaced by hysteresis cycles and subcriticality until the weak branch disappears entirely and the strong branch onsets in a turbulent state at Ekforcing decreases well below the linear onset of convection (Ra 0.4Racrit in this study for Ek=10-10 and Pr=0.01). We highlight the importance of the Reynolds stress, which is required for convection to persist below the linear onset. We further note the presence of a strong zonal flow that is nonetheless unimportant to the convective subcritical state. Our study suggests that, in the asymptotic regime of rapid rotation relevant for planetary interiors, thermal convection of liquid metals in a sphere onsets and shuts down through a subcritical bifurcation. This scenario may be relevant to explain the lunar and martian dynamo extinctions.

Single-laboratory validation of a high-performance liquid chromatographic-diode array detector-fluorescence detector/mass spectrometric method for simultaneous determination of water-soluble vitamins in multivitamin dietary tablets.

Science.gov (United States)

Chen, Pei; Atkinson, Renata; Wolf, Wayne R

2009-01-01

The purpose of this study was to develop a single-laboratory validated (SLV) method using high-performance liquid chromatography with different detectors [diode array detector (DAD); fluorescence detector (FLD); and mass spectrometry (MS)] for determination of 7 B-complex vitamins (B1-thiamin, B2-riboflavin, B3-nicotinamide, B6-pyridoxine, B9-folic acid, pantothenic acid, and biotin) and vitamin C in multivitamin/multimineral dietary supplements. The method involves the use of a reversed-phase octadecylsilyl column (4 microm, 250 x 2.0 mm id) and a gradient mobile phase profile. Gradient elution was performed at a flow rate of 0.25 mL/min. After a 5 min isocratic elution at 100% A (0.1% formic acid in water), a linear gradient to 50% A and 50% B (0.1% formic acid in acetonitrile) at 15 min was employed. Detection was performed with a DAD as well as either an FLD or a triple-quadrupole MS detector in the multiple reaction monitoring mode. SLV was performed using Standard Reference Material (SRM) 3280 Multivitamin/Multimineral Tablets, being developed by the National Institute of Standards and Technology, with support by the Office of Dietary Supplements of the National Institutes of Health. Phosphate buffer (10 mM, pH 2.0) extracts of the NIST SRM 3280 were analyzed by the liquid chromatographic (LC)-DAD-FLDIMS method. Following extraction, the method does not require any sample cleanup/preconcentration steps except centrifugation and filtration.

Dispersive liquid-liquid microextraction and gas chromatography accurate mass spectrometry for extraction and non-targeted profiling of volatile and semi-volatile compounds in grape marc distillates.

Science.gov (United States)

Fontana, Ariel; Rodríguez, Isaac; Cela, Rafael

2018-04-20

The suitability of dispersive liquid-liquid microextraction (DLLME) and gas chromatography accurate mass spectrometry (GC-MS), based on a time-of-flight (TOF) MS analyzer and using electron ionization (EI), for the characterization of volatile and semi-volatile profiles of grape marc distillates (grappa) are evaluated. DLLME conditions are optimized with a selection of compounds, from different chemical families, present in the distillate spirit. Under final working conditions, 2.5 mL of sample and 0.5 mL of organic solvents are consumed in the sample preparation process. The absolute extraction efficiencies ranged from 30 to 100%, depending on the compound. For the same sample volume, DLLME provided higher responses than solid-phase microextraction (SPME) for most of the model compounds. The GC-EI-TOF-MS records of grappa samples were processed using a data mining non-targeted search algorithm. In this way, chromatographic peaks and accurate EI-MS spectra of sample components were linked. The identities of more than 140 of these components are proposed from comparison of their accurate spectra with those in a low resolution EI-MS database, accurate masses of most intense fragment ions of known structure, and available chromatographic retention index. The use of chromatographic and spectral data, associated to the set of components mined from different grappa samples, for multivariate analysis purposes is also illustrated in the study. Copyright © 2018 Elsevier B.V. All rights reserved.

Analysis of s-triazine herbicides in model systems and samples of groundwater by gas and liquid chromatography

Directory of Open Access Journals (Sweden)

Kostadinović Ljiljana

2010-01-01

Full Text Available In this paper, residues of s-triazine herbicides (Simazine, Atrazine, Amethrine, Promethrine and Azyprothrine have been determined in samples of model systems and real groundwater samples by gas-chromatography and high performance liquid chromatography. S-triazine herbicides were isolated from water samples by chloroform-methanol mixture (1:1, followed by purification of extract on the Al2O3 column. Gas-chromatographic determination the residues of s-triazines is performed on parallel capilar columns ULTRA I and ULTRA II, using specific NP detector. Liquid-chromatographic determination the s-triazines was performed on the column TSK ODS-120 A 5 mm 'LKB', using the mobile phase methanol-water (60:40. Total concentration of s-triazines in samples of Danube water was 3.54 mg dm-3. .

Analyzing chromatographic data using multilevel modeling.

Science.gov (United States)

Wiczling, Paweł

2018-06-01

It is relatively easy to collect chromatographic measurements for a large number of analytes, especially with gradient chromatographic methods coupled with mass spectrometry detection. Such data often have a hierarchical or clustered structure. For example, analytes with similar hydrophobicity and dissociation constant tend to be more alike in their retention than a randomly chosen set of analytes. Multilevel models recognize the existence of such data structures by assigning a model for each parameter, with its parameters also estimated from data. In this work, a multilevel model is proposed to describe retention time data obtained from a series of wide linear organic modifier gradients of different gradient duration and different mobile phase pH for a large set of acids and bases. The multilevel model consists of (1) the same deterministic equation describing the relationship between retention time and analyte-specific and instrument-specific parameters, (2) covariance relationships relating various physicochemical properties of the analyte to chromatographically specific parameters through quantitative structure-retention relationship based equations, and (3) stochastic components of intra-analyte and interanalyte variability. The model was implemented in Stan, which provides full Bayesian inference for continuous-variable models through Markov chain Monte Carlo methods. Graphical abstract Relationships between log k and MeOH content for acidic, basic, and neutral compounds with different log P. CI credible interval, PSA polar surface area.

Determination of albendazole sulfoxide in human plasma by using liquid chromatography-tandem mass spectrometry.

Science.gov (United States)

Saraner, Nihal; Özkan, Güler Yağmur; Güney, Berrak; Alkan, Erkin; Burul-Bozkurt, Nihan; Sağlam, Onursal; Fikirdeşici, Ezgi; Yıldırım, Mevlüt

2016-06-01

A rapid, simple and sensitive method was developed and validated using liquid chromatography-tandem mass spectrometry (LC-MS/MS) for determination of albendazole sulfoxide (ABZOX) in human plasma. The plasma samples were extracted by protein precipitation using albendazole sulfoxide-d3 as internal standard (IS). The chromatographic separation was performed on Waters Xbridge C18Column (100×4.6mm, 3.5μm) with a mobile phase consisting of ammonia solution, water and methanol at a flow rate of 0.70mL/min. ABZOX was detected and identified by mass spectrometry with electrospray ionization (ESI) in positive ion and multiple-reaction monitoring (MRM) mode. The method was linear in the range of 3-1500ng/mL for ABZOX. This method was successfully applied to the bioequivalence study in human plasma samples. Copyright © 2016 Elsevier B.V. All rights reserved.

Stationary and through-flow radiochemical detectors in cooperation with high performance liquid chromatography: Application in biochemistry

International Nuclear Information System (INIS)

Kehr, J.

1986-01-01

A review article is presented containing some original experimental data and discussing the usability of radiochemical detection of labelled compounds using high performance liquid chromatography. The stationary and through-flow types of detection are compared with respect to efficiency, chromatographic zone resolution, usability in biochemical research, and also to the current trends of development of liquid chromatography. (author). 3 figs., 1 tab., 19 refs

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.

High-performance liquid chromatographic method for the determination of nicardipine in pure, pharmaceutical preparations and plasma and its application to pharmacokinetics in humans

Directory of Open Access Journals (Sweden)

Sheikha M. Al-Ghannam

2009-01-01

Full Text Available A simple, sensitive and reproducible reversed-phase liquid chromatographic method has been developed and validated for the determination of nicardipine hydrochloride (NC in pure, pharmaceutical preparations, human plasma and the study of the pharmacokinetics of the drug in human body. Nicardipine in plasma were extracted with hexane-butanol (12:1,v/v after addition of borate buffer (0.5 M, pH=9.0, and then measured by HPLC-UV using a Waters Symmetry C18 column as stationary phase and methanol– triethylamine buffer (0.01M pH 4 with acetic acid (70:30 as mobile phase. Nicardipine was quantified by ultraviolet absorbance at 353 nm. The method proved to be linear in the pure drug in the ranges of 15-200 ng/mL (r=0.9989 and 5-40 ?g/mL (r=0.9995, and for the pharmaceutical preparations and plasma for drug concentrations in the range of 5-40 ?g/mL (r =0.9992 and 25-150 ng/mL (r=0.9991, respectively. The lower limit of detection and the lower quantitation limit of NC in plasma were 11.74 and 35.57 ng/mL, respectively. The method is sensitive and reliable for harmacokineticstudies of nicardipine in humans after the oral administration of immediate-release capsules to healthy subjects.

High-performance liquid chromatographic method for the determination of nicardipine in pure, pharmaceutical preparations and plasma and its application to pharmacokinetics in humans

Directory of Open Access Journals (Sweden)

Sheikha Mohammed Al-Ghannam

2008-12-01

Full Text Available A simple, sensitive and reproducible reversed-phase liquid chromatographic method has been developed and validated for the determination of nicardipine hydrochloride (NC in pure, pharmaceutical preparations, human plasma and the study of the pharmacokinetics of the drug in human body. Nicardipine in plasma were extracted with hexane-butanol (12:1,v/v after addition of borate buffer (0.5 M, pH=9.0, and then measured by HPLC-UV using a Waters Symmetry C18 column as stationary phase and methanol– triethylamine buffer (0.01M pH 4 with acetic acid (70:30 as mobile phase. Nicardipine was quantified by ultraviolet absorbance at 353 nm. The method proved to be linear in the pure drug in the ranges of 15-200 ng/mL (r=0.9989 and 5-40 µg/mL (r=0.9995, and for the pharmaceutical preparations and plasma for drug concentrations in the range of 5-40 µg/mL (r =0.9992 and 25-150 ng/mL (r=0.9991, respectively. The lower limit of detection and the lower quantitation limit of NC in plasma were 11.74 and 35.57 ng/mL, respectively. The method is sensitive and reliable for pharmacokinetic studies of nicardipine in humans after the oral administration of immediate-release capsules to healthy subjects.

Choline chloride-based deep eutectic solvents as additives for optimizing chromatographic behavior of caffeic acid

International Nuclear Information System (INIS)

Li, Guizhen; Zhu, Tao; Lei, Yingjie

2015-01-01

A series of deep eutectic solvents (DESs) were prepared using glycerol and choline chloride (ChCl), and Fourier transform infrared spectrometer (FT-IR) was used to analyze the spectra of glycerol, choline chloride and DESs based on glycerol and choline chloride. Then DESs were used as the additives of mobile phase to optimize chromatographic behavior of caffeic acid in high performance liquid chromatography (HPLC). A 17-run Box-Behnken design (BBD) was employed to evaluate effect of DESs as additives by analyzing the maximum theoretical plate number. Three factors, reaction temperature (60 .deg. C, 80 .deg. C, 100 .deg. C), molar ratio of glycerol and choline chloride (2 : 1, 3 : 1, 4 : 1, n/n), and volume percent of additives (0.05%, 0.10%, 0.15%, v/v), were investigated in BBD. The optimum experiment condition was that of reaction temperature (80 .deg. C), molar ratio of glycerol and ChCl (3 : 1, n/n), and volume percent of additive (0.10%, v/v). The mean chromatographic theoretical plate number of the caffeic acid this condition was 1567.5, and DESs as additives shorten the retention time and modify the chromatogram shape, proving DESs as additives for effective theoretical plate number and column efficiency in HPLC.

Choline chloride-based deep eutectic solvents as additives for optimizing chromatographic behavior of caffeic acid

Energy Technology Data Exchange (ETDEWEB)

Li, Guizhen; Zhu, Tao; Lei, Yingjie [Tianjin University of Technology, Tianjin (China)

2015-10-15

A series of deep eutectic solvents (DESs) were prepared using glycerol and choline chloride (ChCl), and Fourier transform infrared spectrometer (FT-IR) was used to analyze the spectra of glycerol, choline chloride and DESs based on glycerol and choline chloride. Then DESs were used as the additives of mobile phase to optimize chromatographic behavior of caffeic acid in high performance liquid chromatography (HPLC). A 17-run Box-Behnken design (BBD) was employed to evaluate effect of DESs as additives by analyzing the maximum theoretical plate number. Three factors, reaction temperature (60 .deg. C, 80 .deg. C, 100 .deg. C), molar ratio of glycerol and choline chloride (2 : 1, 3 : 1, 4 : 1, n/n), and volume percent of additives (0.05%, 0.10%, 0.15%, v/v), were investigated in BBD. The optimum experiment condition was that of reaction temperature (80 .deg. C), molar ratio of glycerol and ChCl (3 : 1, n/n), and volume percent of additive (0.10%, v/v). The mean chromatographic theoretical plate number of the caffeic acid this condition was 1567.5, and DESs as additives shorten the retention time and modify the chromatogram shape, proving DESs as additives for effective theoretical plate number and column efficiency in HPLC.

Environmental Chemistry Compound Identification Using High Resolution Mass Spectrometry Data Integrated to the EPA Chemistry Dashboard (EAS)

Science.gov (United States)

There is a growing need for rapid chemical screening and prioritization to inform regulatory decision-making on thousands of chemicals in the environment. We have previously used high-resolution mass spectrometry to examine household vacuum dust samples using liquid chromatograph...

Constant pressure mode extended simple gradient liquid chromatography system for micro and nanocolumns

Czech Academy of Sciences Publication Activity Database

Šesták, Jozef; Kahle, Vladislav

2014-01-01

Roč. 1350, Jul (2014), s. 68-71 ISSN 0021-9673 R&D Projects: GA MV VG20102015023 Institutional support: RVO:68081715 Keywords : constant pressure HPLC * gradient elution * simple liquid chromatograph Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 4.169, year: 2014 http://hdl.handle.net/11104/0233990

A rapid high-performance liquid-chromatographic method for simultaneously determining the concentrations of TFM and Bayer 73 in water during lampricide treatments

Science.gov (United States)

Dawson, V.K.

1982-01-01

The high-performance liquid-chromatography (HPLC) procedure requires only minutes per sample, is specific, and is relatively sensitive (limit of detection 18 disposable cartridge. The cartridge adsorbs and retains both the lampricides and the internal standard. The quantitative elution of the three chemicals from the cartridge with a small volume of methanol effectively concentrates the sample and provides sample cleanup. The methanol extract is then analyzed directly by HPLC on an MCH 10 reverse phase column by using a methanol:0.01 mol/L acetate buffer (87:13, v:v) as the mobile phase at 2 mL/min and detected by ultraviolet spectrophotometry at 330 (or 254) nm. A microprocessor data system further facilitates the procedure by quantifying off-scale peaks and yielding results directly in units of concentration (mg/L).

Water quality for liquid wastes

International Nuclear Information System (INIS)

Mizuniwa, Fumio; Maekoya, Chiaki; Iwasaki, Hitoshi; Yano, Hiroaki; Watahiki, Kazuo.

1985-01-01

Purpose: To facilitate the automation of the operation for a liquid wastes processing system by enabling continuous analysis for the main ingredients in the liquid wastes accurately and rapidly. Constitution: The water quality monitor comprises a sampling pipeway system for taking out sample water for the analysis of liquid wastes from a pipeway introducing liquid wastes to the liquid wastes concentrator, a filter for removing suspended matters in the sample water and absorption photometer as a water quality analyzer. A portion of the liquid wastes is passed through the suspended matter filter by a feedpump. In this case, sulfate ions and chloride ions in the sample are retained in the upper portion of a separation color and, subsequently, the respective ingredients are separated and leached out by eluting solution. Since the leached out ingredients form ferric ions and yellow complexes respectively, their concentrations can be detected by the spectrum photometer. Accordingly, concentration for the sodium sulfate and sodium chloride in the liquid wastes can be analyzed rapidly, accurately and repeatedly by which the water quality can be determined rapidly and accurately. (Yoshino, Y.)

Liquid-phase microextraction for simultaneous chromatographic analysis of three antidepressant drugs in plasma

Directory of Open Access Journals (Sweden)

Carlos Eduardo Dobrovolskni Porto

2012-01-01

Full Text Available A method using Liquid Phase Microextraction for simultaneous detection of citalopram (CIT, paroxetine (PAR and fluoxetine (FLU, using venlafaxine as internal standard, in plasma by high performance liquid chromatography with fluorescence detection was developed. The linearity was evaluated between 5.0 and 500 ng mL-1 (r > 0.99 and the limit of quantification was 2.0, 3.0 and 5.0 ng mL-1 for CIT, PAR and FLU, respectively. Therefore, it can be applied to therapeutic drug monitoring, pharmacokinetics or bioavailability studies and its advantages are that it necessary relatively inexpensive equipment and sample preparation techniques.

Isotope Fractionation in Methane Reactions Studied by Gas Chromatography and Liquid Scintillation

DEFF Research Database (Denmark)

Andersen, Bertel Lohmann; Bidoglio, G.; Leip, A.

1997-01-01

Determination of C-14-marked methane by gas chromatography and liquid scintillation counting is shown to be useful in studies of isotope effects. Data on the specific activity is used to separate the contributions of (CH4)-C-14, and (CH4)-C-12 to the gas-chromatographic peak area. As an application...

Chromatographic studies of thorium(IV) and its extraction from monazite sand

International Nuclear Information System (INIS)

Bandyopadhyay, Arup; Roy, Uday Sankar

1998-01-01

A simple, rapid and selective method has been developed for reversed phase extraction chromatographic studies of Th IV with high molecular mass monocarboxylic acid (C 15 -C 16 ), SRS-100 as a stationary phase on a column of silica gel. Quantitative extraction of Th IV has been achieved in the pH range 4.8-5.5. The extracted Th IV has been stripped with 1:1 (v/v) mixture of 0.2 M HNO 3 and 0.2 M NaNO 3 and estimated spectrophotometrically. The effect of variables as pH, stripping agents, flow rate on extraction and elution have been studied. Th IV has been separated from various commonly associated elements in binary and synthetic multicomponent mixtures. The method has been applied successfully for the extraction of thorium from monazite sand. (author)

Quality by Design approach in the development of hydrophilic interaction liquid chromatographic method for the analysis of iohexol and its impurities.

Science.gov (United States)

Jovanović, Marko; Rakić, Tijana; Tumpa, Anja; Jančić Stojanović, Biljana

2015-06-10

This study presents the development of hydrophilic interaction liquid chromatographic method for the analysis of iohexol, its endo-isomer and three impurities following Quality by Design (QbD) approach. The main objective of the method was to identify the conditions where adequate separation quality in minimal analysis duration could be achieved within a robust region that guarantees the stability of method performance. The relationship between critical process parameters (acetonitrile content in the mobile phase, pH of the water phase and ammonium acetate concentration in the water phase) and critical quality attributes is created applying design of experiments methodology. The defined mathematical models and Monte Carlo simulation are used to evaluate the risk of uncertainty in models prediction and incertitude in adjusting the process parameters and to identify the design space. The borders of the design space are experimentally verified and confirmed that the quality of the method is preserved in this region. Moreover, Plackett-Burman design is applied for experimental robustness testing and method is fully validated to verify the adequacy of selected optimal conditions: the analytical column ZIC HILIC (100 mm × 4.6 mm, 5 μm particle size); mobile phase consisted of acetonitrile-water phase (72 mM ammonium acetate, pH adjusted to 6.5 with glacial acetic acid) (86.7:13.3) v/v; column temperature 25 °C, mobile phase flow rate 1 mL min(-1), wavelength of detection 254 nm. Copyright © 2015 Elsevier B.V. All rights reserved.

Validated stability indicating liquid chromatographic determination of ebastine in pharmaceuticals after pre column derivatization: Application to tablets and content uniformity testing

Directory of Open Access Journals (Sweden)

Eid Manal

2011-05-01

Full Text Available Abstract An accurate, simple, sensitive and selective reversed phase liquid chromatographic method has been developed for the determination of ebastine in its pharmaceutical preparations. The proposed method depends on the complexation ability of the studied drug with Zn2+ ions. Reversed phase chromatography was conducted using an ODS C18 (150 × 4.6 mm id stainless steel column at ambient temperature with UV-detection at 260 nm. A mobile phase containing 0.025%w/v Zn2+ in a mixture of (acetonitril/methanol; 1/4 and Britton Robinson buffer (65:35, v/v adjusted to pH 4.2, has been used for the determination of ebastine at a flow rate of 1 ml/min. The calibration curve was rectilinear over the concentration range of 0.3 - 6.0 μg/ml with a detection limit (LOD of 0.13 μg/ml, and quantification limit (LOQ of 0.26 μg/ml. The proposed method was successfully applied for the analysis of ebastine in its dosage forms, the obtained results were favorably compared with those obtained by a comparison method. Furthermore, content uniformity testing of the studied pharmaceutical formulations was also conducted. The composition of the complex as well as its stability constant was also investigated. Moreover, the proposed method was found to be a stability indicating one and was utilized to investigate the kinetics of alkaline and ultraviolet induced degradation of the drug. The first-order rate constant and half life of the degradation products were calculated.

Chromatographic and biological aspects of organomercurials

Energy Technology Data Exchange (ETDEWEB)

Fishbein, L

1970-01-01

A thorough review on the biological and chromatographic aspects of methylmercury, phenylmercurials, and miscellaneous organomercurials is presented. Areas covered include ecology, epidemiology, paper chromatography, thin-layer chromatography, gas chromatography, metabolism and toxicity, and environmental degradation. 183 references.

[Rapid determination of theophylline, theobromine and caffeine in dietary supplements containing guarana by ultra-performance liquid chromatography].

Science.gov (United States)

Hasegawa, Takashi; Takahashi, Kazunaga; Saijo, Masaaki; Ishii, Toshiyasu; Nagata, Tomoko

2009-12-01

A rapid and simple method for determination of theophylline, theobromine and caffeine in dietary supplements containing guarana by ultra-performance liquid chromatography (UPLC) has been developed. Theophylline, theobromine and caffeine were extracted from finely powdered samples with water in a boiling water bath for 20 min, then the extracts were filtered and the filtrates were subjected to UPLC. Liquid samples were diluted with water and filteres, and the filtrates were subjected to UPLC. UPLC separation was performed on an AQUITY UPLC BEH C18 column (2.1 mm i.d.x50 mm, 1.7 microm, Waters) with 10 mmol/L ammonium acetate buffer (pH 4.0)-acetonitrile gradient and eluates were monitored at 275 nm. The recoveries of theophylline (spiked at 200 microg/g [tablet] and 50 microg/mL [liquid]), theobromine (spiked at 200 microg/g [tablet] and 50 microg/mL [liquid]) and caffeine (spiked at 1,000 microg/g [tablet] and 250 microg/mL [liquid]) were 97.6-98.7%, 97.3-99.7%, 97.1-105.4%, respectively. The quantitation limits of theophylline, theobromine and caffeine were 10 microg/g (seed, seed powder, tablet and capsule) and 2.0 microg/mL (liquid) each. When this analytical method was applied to commercial dietary supplements, theophylline, theobromine and caffeine were found at concentrations of 4.45 mg/tablet, 5.48 mg/tablet, 139 mg/tablet, respectively. Taking 4 tablets of this product according to the directions on the package could be dangerous to consumers because of possible overdosing of these ingredients.

Electrochemically modulated liquid chromatography: Theoretical investigations and applications from the perspectives of chromatography and interfacial electrochemistry

Energy Technology Data Exchange (ETDEWEB)

Keller, David W. [Iowa State Univ., Ames, IA (United States)

2005-01-01

Electrochemically modulated liquid chromatography (EMLC) employs a conductive material as both a stationary phase for chromatographic separations and as a working electrode for performing electrochemistry experiments. This dual functionality gives EMLC the capacity to manipulate chromatographic separations by changing the potential applied (E_app) to the stationary phase with respect to an external reference. The ability to monitor retention as a function of E_app provides a means to chromatographically monitor electrosorption processes at solid-liquid interfaces. In this dissertation, the retention mechanism for EMLC is examined from the perspective of electrical double layer theory and interfacial thermodynamics. From the chromatographic data, it is possible to determine the interfacial excess (Λ) of a solute and changes in interfacial tension (dγ) as a function of both E_app and the supporting electrolyte concentration. Taken together, these two experimentally manipulated parameters can be examined within the context of the Gibbs adsorption equation to delineate the contribution of a variety of interfacial properties, including the charge of solute on the stationary phase and the potential of zero charge (PZC), to the mechanism behind EMLC-based retention. The chromatographic probing of interfacial phenomena is complemented by electroanalytical experiments that exploit the ability to monitor the electronic current flowing through an EMLC column. Cyclic voltammetry and chronoamperometry of an EMLC column are used to determine the electronic performance characteristics of an EMLC column. An electrochemical flow injection analysis of a column is provided in which the current required to maintain a constant E_app is monitored and provides a way to examine the influence that acetonitrile and supporting electrolyte composition, flow rate, column backpressure, and ionic strength have on the structure of electrified interfaces.

High-performance liquid chromatographic determination of histamine in biological samples: the cerebrospinal fluid challenge--a review.

Science.gov (United States)

Wang, Zhaopin; Wu, Juanli; Wu, Shihua; Bao, Aimin

2013-04-24

Histamine, a neurotransmitter crucially involved in a number of basic physiological functions, undergoes changes in neuropsychiatric disorders. Detection of histamine in biological samples such as cerebrospinal fluid (CSF) is thus of clinical importance. The most commonly used method for measuring histamine levels is high performance liquid chromatography (HPLC). However, factors such as very low levels of histamine, the even lower CSF-histamine and CSF-histamine metabolite levels, especially in certain neuropsychiatric diseases, rapid formation of histamine metabolites, and other confounding elements during sample collection, make analysis of CSF-histamine and CSF-histamine metabolites a challenging task. Nonetheless, this challenge can be met, not only with respect to HPLC separation column, derivative reagent, and detector, but also in terms of optimizing the CSF sample collection. This review aims to provide a general insight into the quantitative analyses of histamine in biological samples, with an emphasis on HPLC instruments, methods, and hyphenated techniques, with the aim of promoting the development of an optimal and practical protocol for the determination of CSF-histamine and/or CSF-histamine metabolites. Copyright © 2013 Elsevier B.V. All rights reserved.

Chromatographic methods

International Nuclear Information System (INIS)

Marhol, M.; Stary, J.

1975-01-01

The characteristics are given of chromatographic separation and the methods are listed. Methods and data on materials used in partition, adsorption, precipitation and ion exchange chromatography are listed and conditions are described under which ion partition takes place. Special attention is devoted to ion exchange chromatography where tables are given to show the course of values of the partition coefficients of different ions in dependence on the concentration of agents and the course of equilibrium sorptions on different materials in dependence on the solution pH. A theoretical analysis is given and the properties of the most widely used ion exchangers are listed. Experimental conditions and apparatus used for each type of chromatography are listed. (L.K.)

Development of a perfusion reversed-phase high performance liquid chromatography method for the characterisation of maize products using multivariate analysis.

Science.gov (United States)

Rodriguez-Nogales, J M; Garcia, M C; Marina, M L

2006-02-03

A perfusion reversed-phase high performance liquid chromatography (RP-HPLC) method has been designed to allow rapid (3.4 min) separations of maize proteins with high resolution. Several factors, such as extraction conditions, temperature, detection wavelength and type and concentration of ion-pairing agent were optimised. A fine optimisation of the gradient elution was also performed by applying experimental design. Commercial maize products for human consumption (flours, precocked flours, fried snacks and extruded snacks) were characterised for the first time by perfusion RP-HPLC and their chromatographic profiles allowed a differentiation among products relating the different technological process used for their preparation. Furthermore, applying discriminant analysis makes it possible to group the samples according with the technological process suffered by maize products, obtaining a good prediction in 92% of the samples.

High performance liquid chromatographic determination of Ginseng saponin by ultraviolet derivatisation

International Nuclear Information System (INIS)

Besso, H.; Saruwatari, Y.; Futamura, K.; Kunihiro, K.; Fuwa, T.; Tanaka, O.

1979-01-01

Ginsenoides Rb 1 , b 2 , c, d, e and g 1 quantitatively reacted with benzoyl chloride in pyridine to afford the respective derivatives having strong UV absorption. The UV-derivatized saponins were separated by high performance liquid chromatography (HPLC), and the saponin-contents of the various Ginseng varieties were determined. It is possible to distinguish white Ginseng from the root hairs of Ginseng by the pattern analysis of HPLC. (orig.) [de

Determination of free formaldehyde in cosmetics containing formaldehyde-releasing preservatives by reversed-phase dispersive liquid-liquid microextraction and liquid chromatography with post-column derivatization.

Science.gov (United States)

Miralles, Pablo; Chisvert, Alberto; Alonso, M José; Hernandorena, Sandra; Salvador, Amparo

2018-03-30

An analytical method for the determination of traces of formaldehyde in cosmetic products containing formaldehyde-releasing preservatives has been developed. The method is based on reversed-phase dispersive liquid-liquid microextraction (RP-DLLME), that allows the extraction of highly polar compounds, followed by liquid chromatography-ultraviolet/visible (LC-UV/vis) determination with post-column derivatization. The variables involved in the RP-DLLME process were studied to provide the best enrichment factors. Under the selected conditions, a mixture of 500 μL of acetonitrile (disperser solvent) and 50 μL of water (extraction solvent) was rapidly injected into 5 mL of toluene sample solution. The extracts were injected into the LC-UV/vis system using phosphate buffer 6 mmol L -1 at pH 2 as mobile phase. After chromatographic separation, the eluate merged with a flow stream of pentane-2,4-dione in ammonium acetate solution as derivatizing reagent and passed throughout a post-column reactor at 85 °C in order to derivatize formaldehyde into 3,5-diacetyl-1,4-dihydrolutidine, according to Hantzsch reaction, which was finally measured spectrophotometrically at 407 nm. The method was successfully validated showing good linearity, an enrichment factor of 86 ± 2, limits of detection and quantification of 0.7 and 2.3 ng mL -1 , respectively, and good repeatability (RSD < 9.2%). Finally, the proposed analytical method was applied to the determination of formaldehyde in different commercial cosmetic samples containing formaldehyde-releasing preservatives, such as bronopol, diazolidinyl urea, imidazolidinyl urea, and DMDM hydantoin, with good relative recovery values (91-113%) thus showing that matrix effects were negligible. The good analytical features of the proposed method besides of its simplicity and affordability, make it useful to carry out the quality control of cosmetic products containing formaldehyde-releasing preservatives. Copyright �

Alternative chromatographic system for the quality control of lipophilic technetium-99m radiopharmaceuticals such as [99mTc(MIBI6]+

Directory of Open Access Journals (Sweden)

D.P. Faria

2015-01-01

Full Text Available Knowledge of the radiochemical purity of radiopharmaceuticals is mandatory and can be evaluated by several methods and techniques. Planar chromatography is the technique normally employed in nuclear medicine since it is simple, rapid and usually of low cost. There is no standard system for the chromatographic technique, but price, separation efficiency and short time for execution must be considered. We have studied an alternative system using common chromatographic stationary phase and alcohol or alcohol:chloroform mixtures as the mobile phase, using the lipophilic radiopharmaceutical [99mTc(MIBI6]+ as a model. Whatman 1 modified phase paper and absolute ethanol, Whatman 1 paper and methanol:chloroform (25:75, Whatman 3MM paper and ethanol:chloroform (25:75, and the more expensive ITLC-SG and 1-propanol:chloroform (10:90 were suitable systems for the direct determination of radiochemical purity of [99mTc(MIBI6]+ since impurities such as 99mTc-reduced-hydrolyzed (RH, 99mTcO4 - and [99mTc(cysteine2]- complex were completely separated from the radiopharmaceutical, which moved toward the front of chromatographic systems while impurities were retained at the origin. The time required for analysis was 4 to 15 min, which is appropriate for nuclear medicine routines.

A Quantitative Gas Chromatographic Ethanol Determination.

Science.gov (United States)

Leary, James J.

1983-01-01

Describes a gas chromatographic experiment for the quantitative determination of volume percent ethanol in water ethanol solutions. Background information, procedures, and typical results are included. Accuracy and precision of results are both on the order of two percent. (JN)

Determination of itopride in human plasma by liquid chromatography coupled to tandem mass spectrometric detection: application to a bioequivalence study.

Science.gov (United States)

Lee, Heon-Woo; Seo, Ji-Hyung; Choi, Seung-Ki; Lee, Kyung-Tae

2007-01-30

A simple method using a one-step liquid-liquid extraction (LLE) with butyl acetate followed by high-performance liquid chromatography (HPLC) with positive ion electrospray ionization tandem mass spectrometric (ESI-MS/MS) detection was developed for the determination of itopride in human plasma, using sulpiride as an internal standard (IS). Acquisition was performed in multiple reaction monitoring (MRM) mode, by monitoring the transitions: m/z 359.5>166.1 for itopride and m/z 342.3>111.6 for IS, respectively. Analytes were chromatographed on an YMC C18 reverse-phase chromatographic column by isocratic elution with 1 mM ammonium acetate buffer-methanol (20: 80, v/v; pH 4.0 adjusted with acetic acid). Results were linear (r2=0.9999) over the studied range (0.5-1000 ng mL(-1)) with a total analysis time per run of 2 min for LC-MS/MS. The developed method was validated and successfully applied to bioequivalence studies of itopride hydrochloride in healthy male volunteers.

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.

A captive solvent method for rapid N-[11C]methylation of secondary amides: application to the benzodiazepine, 4'-chlorodiazepam (RO5-4864)

International Nuclear Information System (INIS)

Watkins, G.L.; Jewett, D.M.; Mulholland, G.K.; Kilbourn, M.R.; Toorongian, S.A.

1988-01-01

[ 11 C]4'-Chlorodiazepam (RO5-4864), for PET studies of peripheral benzodiazepine receptors, was synthesized by alkylation of 1-desmethyl-4'-chlorodiazepam, in a small volume of acetone adsorbed on acrylic yarn, with [ 11 C]methyl iodide in the injection loop of a liquid chromatograph. The reaction mixture was introduced directly onto a small, disposable alumina chromatographic column. Elution with pentane: ethanol gave a product of high chemical and radiochemical purity. A simple heating and cooling device for the injection loop is described. (author)

Fast, simple and efficient salting-out assisted liquid-liquid extraction of naringenin from fruit juice samples prior to their enantioselective determination by liquid chromatography.

Science.gov (United States)

Magiera, Sylwia; Kwietniowska, Ewelina

2016-11-15

In this study, an easy, simple and efficient method for the determination of naringenin enantiomers in fruit juices after salting-out-assisted liquid-liquid extraction (SALLE) and high-performance liquid chromatography (HPLC) with diode-array detection (DAD) was developed. The sample treatment is based on the use of water-miscible acetonitrile as the extractant and acetonitrile phase separation under high-salt conditions. After extraction, juice samples were incubated with hydrochloric acid in order to achieve hydrolysis of naringin to naringenin. The hydrolysis parameters were optimized by using a half-fraction factorial central composite design (CCD). After sample preparation, chromatographic separation was obtained on a Chiralcel® OJ-RH column using the mobile phase consisting of 10mM aqueous ammonium acetate:methanol:acetonitrile (50:30:20; v/v/v) with detection at 288nm. The average recovery of the analyzed compounds ranged from 85.6 to 97.1%. The proposed method was satisfactorily used for the determination of naringenin enantiomers in various fruit juices samples. Copyright © 2016 Elsevier Ltd. All rights reserved.

Development of high performance liquid chromatography for rapid determination of burn-up of nuclear fuels

International Nuclear Information System (INIS)

Joseph, M.; Karunasagar, D.; Saha, B.

1996-01-01

Burn-up an important parameter during evaluation of the performance of any nuclear fuel. Among the various techniques available, the preferred one for its determination is based on accurate measurement of a suitable fission product monitor and the residual heavy elements. Since isotopes of rare earth elements are generally used as burn-up monitors, conditions were standardized for rapid separation (within 15 minutes) of light rare earths using high performance liquid chromatography based on either anion exchange (Partisil 10 SAX) in methanol-nitric acid medium or by cation exchange on a reverse phase column (Spherisorb 5-ODS-2 or Supelcosil LC-18) dynamically modified with 1-octane sulfonate or camphor-10-sulfonic acid (β). Both these methods were assessed for separation of individual fission product rare earths from their mixtures. A new approach has been examined in detail for rapid assay of neodymium, which appears promising for faster and accurate measurement of burn-up. (author)

Lithium adduct as precursor ion for sensitive and rapid quantification of 20 (S)-protopanaxadiol in rat plasma by liquid chromatography/quadrupole linear ion trap mass spectrometry and application to rat pharmacokinetic study.

Science.gov (United States)

Bao, Yuanwu; Wang, Quanying; Tang, Pingming

2013-03-01

A novel, rapid and sensitive liquid chromatography/quadrupole linear ion trap mass spectrometry [LC-ESI-(QqLIT)MS/MS] method was developed and validated for the quantification of protopanaxadiol (PPD) in rat plasma. Oleanolic acid (OA) was used as internal standard (IS). A simple protein precipitation based on acetonitrile (ACN) was employed. Chromatographic separation was performed on a Sepax GP-C18 column (50 × 2.1 mm, 5 μM) with a mobile phase consisting of ACN-water and 1.5 μM formic acid and 25 mM lithium acetate (90 : 10, v/v) at a flow rate of 0.4 ml/min for 3.0 min. Multiple-reaction-monitoring mode was performed using lithium adduct ion as precursor ion of m/z 467.5/449.4 and 455.6/407.4 for the drug and IS, respectively. Calibration curve was recovered over a concentration range of 0.5-100 ng/ml with a correlation coefficient >0.99. The limit of detection was 0.2 ng/ml in rat plasma for PPD. The results of the intraday and interday precision and accuracy studies were well within the acceptable limits. The validated method was successfully applied to investigate the pharmacokinetic study of PPD after intravenous and gavage administration to rat. Copyright © 2013 John Wiley & Sons, Ltd.

Optimization of the analysis by means of liquid chromatography of metabolites of the Uncaria Tomentosa plant (cat's claw) using the sequential simplex method

International Nuclear Information System (INIS)

Romero Blanco, Eric

2005-01-01

A new method was developed for the analysis using liquid chromatography of the metabolites present in extracts of root bark of Uncaria Tomentosa (cat's claw) by applying the simplex sequential technique to determine the magnitude of the chromatographic variables; i.e. flow, temperature and stationary-phase composition, which allowed the optimizing the elusion time and the resolution of the chromatographic separation. The chromatographic analysis was performed in isocratic mode using a C12 (-urea) column of 15 cm in length and 4,6 mm of diameter and a UV detector. The magnitude of the chromatographic variables that optimized the separation turned out to be: flow of 1.80 mL/min, temperature of 27.5 centigrade and a mobile phase composition of 22:78 (Methanol: to butter). (Author) [es

Applications of the solvation parameter model in reversed-phase liquid chromatography.

Science.gov (United States)

Poole, Colin F; Lenca, Nicole

2017-02-24

The solvation parameter model is widely used to provide insight into the retention mechanism in reversed-phase liquid chromatography, for column characterization, and in the development of surrogate chromatographic models for biopartitioning processes. The properties of the separation system are described by five system constants representing all possible intermolecular interactions for neutral molecules. The general model can be extended to include ions and enantiomers by adding new descriptors to encode the specific properties of these compounds. System maps provide a comprehensive overview of the separation system as a function of mobile phase composition and/or temperature for method development. The solvation parameter model has been applied to gradient elution separations but here theory and practice suggest a cautious approach since the interpretation of system and compound properties derived from its use are approximate. A growing application of the solvation parameter model in reversed-phase liquid chromatography is the screening of surrogate chromatographic systems for estimating biopartitioning properties. Throughout the discussion of the above topics success as well as known and likely deficiencies of the solvation parameter model are described with an emphasis on the role of the heterogeneous properties of the interphase region on the interpretation and understanding of the general retention mechanism in reversed-phase liquid chromatography for porous chemically bonded sorbents. Copyright © 2016 Elsevier B.V. All rights reserved.

Optimized and validated high-performance liquid chromatography method for the determination of deoxynivalenol and aflatoxins in cereals.

Science.gov (United States)

Skendi, Adriana; Irakli, Maria N; Papageorgiou, Maria D

2016-04-01

A simple, sensitive and accurate analytical method was optimized and developed for the determination of deoxynivalenol and aflatoxins in cereals intended for human consumption using high-performance liquid chromatography with diode array and fluorescence detection and a photochemical reactor for enhanced detection. A response surface methodology, using a fractional central composite design, was carried out for optimization of the water percentage at the beginning of the run (X1, 80-90%), the level of acetonitrile at the end of gradient system (X2, 10-20%) with the water percentage fixed at 60%, and the flow rate (X3, 0.8-1.2 mL/min). The studied responses were the chromatographic peak area, the resolution factor and the time of analysis. Optimal chromatographic conditions were: X1 = 80%, X2 = 10%, and X3 = 1 mL/min. Following a double sample extraction with water and a mixture of methanol/water, mycotoxins were rapidly purified by an optimized solid-phase extraction protocol. The optimized method was further validated with respect to linearity (R(2) >0.9991), sensitivity, precision, and recovery (90-112%). The application to 23 commercial cereal samples from Greece showed contamination levels below the legally set limits, except for one maize sample. The main advantages of the developed method are the simplicity of operation and the low cost. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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

Science.gov (United States)

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

2018-03-01

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

Fast simultaneous analysis of caffeine, trigonelline, nicotinic acid and sucrose in coffee by liquid chromatography-mass spectrometry.

Science.gov (United States)

Perrone, Daniel; Donangelo, Carmen Marino; Farah, Adriana

2008-10-15

A rapid liquid chromatography-mass spectrometry method for the simultaneous quantification of caffeine, trigonelline, nicotinic acid and sucrose in coffee was developed and validated. The method involved extraction with hot water, clarification with basic lead acetate and membrane filtration, followed by chromatographic separation using a Spherisorb(®) S5 ODS2, 5μm chromatographic column and gradient elution with 0.3% aqueous formic acid/methanol at a flow rate of 0.2mL/min. The electrospray ionization source was operated in the negative mode to generate sucrose ions and in the positive mode to generate caffeine, trigonelline and nicotinic acid ions. Ionization suppression of all analytes was found due to matrix effect. Calibrations curves prepared in green and roasted coffee extracts were linear with r(2)>0.999. Roasted coffee was spiked and recoveries ranged from 93.0% to 105.1% for caffeine, from 85.2% to 116.2% for trigonelline, from 89.6% to 113.5% for nicotinic acid and from 94.1% to 109.7% for sucrose. Good repeatibilities (RSDcoffee samples (regular or decaffeinated green, ground roasted and instant) gave results in agreement with the literature. The method showed to be suitable for different types of coffee available in the market thus appearing as a fast and reliable alternative method to be used for routine coffee analysis. Copyright © 2008 Elsevier Ltd. All rights reserved.

A technique for rapid source apportionment applied to ambient organic aerosol measurements from a thermal desorption aerosol gas chromatograph (TAG

Directory of Open Access Journals (Sweden)

Y. Zhang

2016-11-01

Full Text Available We present a rapid method for apportioning the sources of atmospheric organic aerosol composition measured by gas chromatography–mass spectrometry methods. Here, we specifically apply this new analysis method to data acquired on a thermal desorption aerosol gas chromatograph (TAG system. Gas chromatograms are divided by retention time into evenly spaced bins, within which the mass spectra are summed. A previous chromatogram binning method was introduced for the purpose of chromatogram structure deconvolution (e.g., major compound classes (Zhang et al., 2014. Here we extend the method development for the specific purpose of determining aerosol samples' sources. Chromatogram bins are arranged into an input data matrix for positive matrix factorization (PMF, where the sample number is the row dimension and the mass-spectra-resolved eluting time intervals (bins are the column dimension. Then two-dimensional PMF can effectively do three-dimensional factorization on the three-dimensional TAG mass spectra data. The retention time shift of the chromatogram is corrected by applying the median values of the different peaks' shifts. Bin width affects chemical resolution but does not affect PMF retrieval of the sources' time variations for low-factor solutions. A bin width smaller than the maximum retention shift among all samples requires retention time shift correction. A six-factor PMF comparison among aerosol mass spectrometry (AMS, TAG binning, and conventional TAG compound integration methods shows that the TAG binning method performs similarly to the integration method. However, the new binning method incorporates the entirety of the data set and requires significantly less pre-processing of the data than conventional single compound identification and integration. In addition, while a fraction of the most oxygenated aerosol does not elute through an underivatized TAG analysis, the TAG binning method does have the ability to achieve molecular level

Quantitative analysis of phylloquinone (vitamin K1) in soy bean oils by high-performance liquid chromatography.

Science.gov (United States)

Zonta, F; Stancher, B

1985-07-19

A high-performance liquid chromatographic method for determining phylloquinone (vitamin K1) in soy bean oils is described. Resolution of vitamin K1 from interfering peaks of the matrix was obtained after enzymatic digestion, extraction and liquid-solid chromatography on alumina. An isocratic reversed-phase chromatography with UV detection was used in the final stage. The quantitation was carried out by the standard addition method, and the recovery of the whole procedure was 88.2%.

Rapid determination of gross alpha and beta activity in seafood utilizing microwave digestion and liquid scintillation counting

International Nuclear Information System (INIS)

Daniel Sas; Jiri Janda; Alena Tokarova

2015-01-01

This paper describes a method for rapid determination of gross alpha and beta activity in seafood using liquid scintillation counting and microwave digestion for fast sample decomposition. The general group of seafood was divided into two groups based on its structure, whether it has shell or not. The selected group of radionuclides was chosen with respect to military significance, radiotoxicity, and possibility of potential misuse. 90 Sr and 239 Pu were selected as model radionuclides. (author)

New ultra-performance liquid chromatography-tandem mass spectrometry method for the determination of irbesartan in human plasma

Directory of Open Access Journals (Sweden)

Tanveer A. Wani

2015-09-01

Full Text Available With the objective of reducing analysis time and maintaining good efficiency, there has been substantial focus on high-speed chromatographic separations and ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS is a preeminent analytical tool for rapid biomedical analysis. In this study a simple, rapid, sensitive, and specific ultra-performance liquid chromatography-MS/MS method was developed and validated for quantification of the angiotensin II receptor antagonist, irbesartan (IRB, in human plasma. After a simple protein precipitation using methanol and acetonitrile, IRB and internal standard (IS telmisartan were separated on Acquity UPLC BEH C18 column (50 mm × 2.1 mm, i.d. 1.7 μm, Waters, Milford, MA, USA using a mobile phase consisted of acetonitrile: methanol: 10 mM ammonium acetate (70: 15: 15 v/v/v with a flow rate of 0.4 mL/min and detected MS/MS in negative ion mode. The ion transitions recorded in multiple reaction monitoring mode were m/z 427.2→193.08 for IRB and m/z 513.2→469.3 for IS. The assay exhibited a linear dynamic range of 2–500 ng/mL for IRB in human plasma with good correlation coefficient of (0.995 and with a lower limit of quantitation of 2 ng/mL. The intra- and interassay precisions were satisfactory; the relative standard deviations did not exceed 9.91%. The proposed UPLC-MS/MS method is simple, rapid, and highly sensitive, and hence it could be reliable for pharmacokinetic and toxicokinetic study in both animals and humans.

Simultaneous determination of piracetam and vincamine by spectrophotometric and high-performance liquid chromatographic methods.

Science.gov (United States)

El-Saharty, Yasser Shaker Ibrahim

2008-01-01

A mixture of piracetam and vincamine was determined by 3 different methods. The first was the determination of piracetam and vincamine using the ratio-spectra first-derivative (DD1) spectrophotometric technique at 209 and 293 nm in concentration ranges of 10-45 and 2-14 microg/mL with mean recoveries of 99.22 +/- 0.72 and 99.67 +/- 0.79%, respectively. The second method was based on the resolution of the 2 components by bivariate calibration depending on a mathematic algorithm that provides simplicity and rapidity. The method depended on quantitative evaluation of the absorbencies at 210 and 225 nm in concentration ranges of 5-45 and 2-14 microg/mL, with mean recoveries of 100.33 +/- 0.54 and 100.44 +/- 0.98% for piracetam and vincamine, respectively. The third method was reversed-phase liquid chromatography using 0.05 M potassium dihydrogen phosphate-methanol (50 + 50, v/v) as the mobile phase, with the pH adjusted to 3.5 with phosphoric acid. The eluent was monitored at 215 nm in concentration ranges of 5-100 and 2-200 microg/mL, with mean recoveries of 99.62 +/- 0.67 and 99.32 +/- 0.85% for piracetam and vincamine, respectively. The suggested procedures were checked using laboratory-prepared mixtures and were successfully applied for the analysis of their pharmaceutical preparation. The methods retained their accuracy and precision when applying the standard addition technique. The results obtained by applying the proposed methods were statistically analyzed and compared with those obtained by the manufacturer's method.

Determination of Regional Intestinal Permeability of Diclofenac and ...

African Journals Online (AJOL)

Purpose: To develop a simple and rapid reversed-phase high performance liquid chromatographic (HPLC) method with UV detection for the simultaneous determination of diclofenac, metoprolol tartrate, phenol red and propyl paraben in intestinal segments. Methods: The mobile phase consisted of 55 % methanol, 45 % of ...

Simultaneous and rapid determination of deoxynivalenol and its acetylate derivatives in wheat flour and rice by ultra high performance liquid chromatography with photo diode array detection.

Science.gov (United States)

Xu, Jiao-Jiao; Zhou, Jian; Huang, Bai-Fen; Cai, Zeng-Xuan; Xu, Xiao-Min; Ren, Yi-Ping

2016-06-01

A simple and reliable method of ultra high performance liquid chromatography coupled with photo-diode array detection has been proposed for the simultaneous determination of deoxynivalenol and its acetylated derivatives in wheat flour and rice, especially focusing on the optimization of sample extraction, cleanup, and chromatographic separation conditions. Sample pretreatment consisted of a first step using a quick, easy, cheap, effective, rugged, and safe based extraction procedure and a subsequent cleanup step based on solid-phase extraction. The method was extensively validated in wheat flour and rice, obtaining satisfactory analytical performance with good linearity (R(2) ≥ 0.999), acceptable recoveries (80.0-104.4%), and repeatability (RSDs 1.3-10.7%). The limits of detection (21.7-57.4 μg/kg) and quantitation (72.3-191.4 μg/kg) for deoxynivalenols were lower than those usually permitted by various countries' legislation in these food matrices. The method was applied to 34 wheat and rice samples. The results were further compared with results of ultra high performance liquid chromatography with electrospray ionization tandem mass spectrometry. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Aging of SRC liquids

Science.gov (United States)

Hara, T.; Jones, L.; Tewari, K. C.; Li, N. C.

1981-02-01

The viscosity of SRC-LL liquid increases when subjected to accelerated aging by bubbling oxygen in the presence of copper strip at 62°C. Precipitates are formed and can be separated from the aged liquid by Soxhlet extraction with pentane. A 30-70 blend of SRC-I with SRC-LL was subjected to oxygen aging in the absence of copper, and the viscosity increased dramatically after 6 days at 62°. The content of preasphaltene and its molecular size increase with time of aging, accompanied by decrease of asphaltene and pentane-soluble contents. For the preasphaltene fraction on aging, gel permeation chromatography shows formation of larger particles. ESR experiments show that with oxygen aging, spin concentration in the preasphaltene fraction decreases. Perhaps some semiquinone, together with di- and tri-substituted phenoxy radicals, generated by oxygen aging of the coal liquid, interact with the free radicals already present in coal to yield larger particles and reduce free radical concentration. We are currently using the very high-field (600-MHz) NMR spectrometer at Mellon Institute to determine changes in structural parameters before and after aging of SRC-II and its chromatographically separated fractions.

A rapid screening procedure for the analysis of proliferation compounds in complex matrices using solid phase microextraction (SPME) and SPME with in-situ derivatization

International Nuclear Information System (INIS)

Alcaraz, A.; Hulsey, S.S.; Andresen, B.D.

1995-01-01

A variety of methods have been established using advanced chromatographic techniques and new detection systems for the analysis of chemical signatures associated with nuclear and chemical weapon (CW) proliferation. Most of these analytical methods are used in the laboratory and seldom applied in the field. The Chemical Weapons Convention (an international treaty to ban chemical weapons) may require the rapid on-site analysis of environmental samples which contain CW agents, their precursors, and/or their degradation products. In addition to the fact that certain countries are involved in CW non-compliance, there is a current uncertainty regarding nuclear proliferation. This also creates new demands on sample work-up and analytical instrumentation use in the field. The isolation and identification of unique chemical signatures in complex samples such as soils, waste tanks, and decontamination solutions would determine non-compliance. However, a primary area of detection research continues to be sample preparation. Most of the established sample cleanup technologies involve liquid/liquid, Soxhlet, or most recently, solid phase extraction (SPE). Despite the success of these traditional sample preparation techniques, they are time consuming and require multi-step procedures (especially when preparing samples for gas chromatographic mass-spectrometric analysis). The goal of this work is to demonstrate the advantages of utilizing SPME and SPME in-situ derivatization techniques to eliminate time consuming steps necessary to prepare a sample for on-site GC-MS. The authors' approach was to compare two SPME fibers and to develop methods to facilitate the isolation of polar and moderately polar proliferation compounds from complex environmental samples. This work will help to evaluate current SPME technologies for use during on-site environmental monitoring analysis

An acridinium sulphonylamide as a new chemiluminescent label for the determination of carboxylic acids in liquid chromatography

NARCIS (Netherlands)

Steijger, O.M.; Kamminga, D.A.; Lingeman, H.; Brinkman, U.A.T.

1998-01-01

The synthesis of a new acridinium sulphonylamide label for the liquid chromatographic determination of carboxylic acids is described. The label 10-methyl-N-(p-tolyl)-N-(p-iodoacetamidobenzenesulphonyl)-9-acridinium carboxamide iodide is synthesized from 9-acridinecarboxylic acid by a seven-step

Sensitive liquid chromatography-tandem mass spectrometry method for quantification of hydrochlorothiazide in human plasma.

Science.gov (United States)

Ramakrishna, N V S; Vishwottam, K N; Manoj, S; Koteshwara, M; Wishu, S; Varma, D P

2005-12-01

A simple, rapid, sensitive and specific liquid chromatography-tandem mass spectrometry method was developed and validated for quantification of hydrochlorothiazide (I), a common diuretic and anti-hypertensive agent. The analyte and internal standard, tamsulosin (II) were extracted by liquid-liquid extraction with diethyl ether-dichloromethane (70:30, v/v) using a Glas-Col Multi-Pulse Vortexer. The chromatographic separation was performed on a reversed-phase column (Waters symmetry C18) with a mobile phase of 10 mm ammonium acetate-methanol (15:85, v/v). The protonated analyte was quantitated in negative ionization by multiple reaction monitoring with a mass spectrometer. The mass transitions m/z 296.1 solidus in circle 205.0 and m/z 407.2 solidus in circle 184.9 were used to measure I and II, respectively. The assay exhibited a linear dynamic range of 0.5-200 ng/mL for hydrochlorothiazide in human plasma. The lower limit of quantitation was 500 pg/mL, with a relative standard deviation of less than 9%. Acceptable precision and accuracy were obtained for concentrations over the standard curve ranges. A run time of 2.5 min for each sample made it possible to analyze a throughput of more than 400 human plasma samples per day. The validated method has been successfully used to analyze human plasma samples for application in pharmacokinetic, bioavailability or bioequivalence studies. (c) 2005 John Wiley & Sons, Ltd.

An ecofriendly green liquid chromatographic method for simultaneous determination of nicotinamide and clindamycin phosphate in pharmaceutical gel for acne treatment

Directory of Open Access Journals (Sweden)

Fawzia Ibrahim

2017-07-01

Full Text Available A new green micellar liquid chromatographic method was developed and validated for the quantitative estimation of nicotinamide (NICO and clindamycin phosphate (CLD in bulk and pharmaceutical gel formulation. The analytes are well resolved in less than 6.0 minutes using micellar mobile phase consisting of 0.10M sodium dodecyl sulfate (SDS, 0.3% triethylamine, and 10% 2-propanol in 0.02M orthophosphoric acid at pH 3.0, running through an Eclipse XDB-C8 column (150 mm×4.6 mm, 5 μm particle size with flow rate 1.0 mL/min. The effluent was monitored with diode array detection at 210 nm. The retention times of NICO and CLD were 3.8 minutes and 5.6 minutes, respectively. The method was validated according to the International Conference on Harmonisation (ICH guidelines in terms of linearity, limit of detection, limit of quantification, accuracy, precision, robustness, and specificity to prove its reliability. Linear correlation was achieved by plotting the peak area of each drug against its concentration. It was found to be rectilinear in the ranges of 1.0–40.0 μg/mL and 0.5–15.0 μg/mL with limits of detection of 0.06 μg/mL and 0.03 μg/mL and limits of quantification of 0.19 μg/mL and 0.09 μg/mL for NICO and CLD, respectively. The method was successfully implemented for the simultaneous determination of the analytes in their bulk powder and combined gel formulation with high % recoveries. The ease of sample treatment facilitates and greatly expedites the treatment with reduced cost and improved accuracy of the procedure.

A novel UHPLC method for the rapid and simultaneous determination of daidzein, genistein and equol in human urine.

Science.gov (United States)

Redruello, Begoña; Guadamuro, Lucía; Cuesta, Isabel; Álvarez-Buylla, Jorge R; Mayo, Baltasar; Delgado, Susana

2015-11-15

This work reports on a novel method involving reverse-phased ultra-high performance liquid chromatography (UHPLC) plus a spectrophotometric photodiode array/fluorescence (FLR) detection system for determining the concentration of equol and major soy isoflavones (daidzein and genistein) in human urine. The proposed method was validated in terms of its linearity, sensitivity, accuracy (recovery) and precision (intra- and inter-day repeatability). The isoflavone profiles of urine samples from a group of menopausal women following oral soy isoflavone supplementation were determined and compared. Screening for equol-producer status was accomplished with high sensitivity (detection limit of the FLR detector 2.93nM). The method involves a short chromatographic run time compared to conventional HPLC methods while allowing for the simultaneous and reliable quantification of daidzein, genistein and equol in human urine. It also allows for the rapid screening of multiple urine samples when testing for equol production status and checking patient adherence to isoflavone treatment regimens. Copyright © 2015 Elsevier B.V. All rights reserved.

On-line gas chromatographic analysis of airborne particles

Science.gov (United States)

Hering, Susanne V [Berkeley, CA; Goldstein, Allen H [Orinda, CA

2012-01-03

A method and apparatus for the in-situ, chemical analysis of an aerosol. The method may include the steps of: collecting an aerosol; thermally desorbing the aerosol into a carrier gas to provide desorbed aerosol material; transporting the desorbed aerosol material onto the head of a gas chromatography column; analyzing the aerosol material using a gas chromatograph, and quantizing the aerosol material as it evolves from the gas chromatography column. The apparatus includes a collection and thermal desorption cell, a gas chromatograph including a gas chromatography column, heated transport lines coupling the cell and the column; and a quantization detector for aerosol material evolving from the gas chromatography column.

Surface-bubble-modulated liquid chromatography: a new approach for manipulation of chromatographic retention and investigation of solute distribution at water/hydrophobic interfaces.

Science.gov (United States)

Nakamura, Keisuke; Nakamura, Hiroki; Saito, Shingo; Shibukawa, Masami

2015-01-20

In this paper, we present a new chromatographic method termed surface-bubble-modulated liquid chromatography (SBMLC), that has a hybrid separation medium incorporated with surface nanobubbles. Nanobubbles or nanoscale gas phases can be fixed at the interface between water and a hydrophobic material by delivering water into a dry column packed with a nanoporous material. The incorporation of a gas phase at the hydrophobic surface leads to the formation of the hybrid separation system consisting of the gas phase, hydrophobic moieties, and the water/hydrophobic interface or the interfacial water. One can change the volume of the gas phase by pressure applied to the column, which in turn alters the area of water/hydrophobic interface or the volume of the interfacial water, while the amount of the hydrophobic moiety remains constant. Therefore, this strategy provides a novel technique not only for manipulating the separation selectivity by pressure but also for elucidating the mechanism of accumulation or retention of solute compounds in aqueous solutions by a hydrophobic material. We evaluate the contributions of the interfacial water at the surface of an octadecyl bonded silica and the bonded layer itself to the retention of various solute compounds in aqueous solutions on the column packed with the material by SBMLC. The results show that the interfacial water formed at the hydrophobic surface has a key role in retention even though its volume is rather small. The manipulation of the separation selectivity of SBMLC for some organic compounds by pressure is demonstrated.

A liquid chromatography-mass spectrometric method for the determination of oak moss allergens atranol and chloroatranol in perfumes

DEFF Research Database (Denmark)

Bossi, Rossana; Rastogi, Suresh Chandra; Bernard, Guillaume

2004-01-01

This paper describes a validated liquid chromatographic-tandem mass spectrometric method for quantitative analysis of the potential oak moss allergens atranol and chloroatranol in perfumes and similar products. The method employs LC-MS-MS with electrospray ionization (ESI) in negative mode...

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.

Rapid and sensitive analysis of melatonin by LC-MS/MS and its application to pharmacokinetic study in dogs

Directory of Open Access Journals (Sweden)

Huimin Zhao

2016-04-01

Full Text Available A rapid and sensitive liquid chromatography tandem mass spectrometry method was established and validated for determination of melatonin in dog plasma using desvenlafaxine as an internal standard (IS. Plasma samples were pretreated by liquid–liquid extraction with ethyl acetate. Chromatographic separation was carried out on a C18 column at a flow rate of 0.2 ml/min by an isocratic mobile phase of methanol : 5 mM ammonium acetate : formic acid (40:60:0.1, v/v/v. Positive ion mode detection was performed using multiple reaction monitoring (MRM at m/z 233.2→174.2 for melatonin and m/z 264.2→58.2 for desvenlafaxine. The method was linear in the concentration range of 0.020–10 ng/ml with a correlation coefficient ≥0.996. The intra- and inter-assay precision (%RSD values were within 12.6% (LLOQ 15.2%, and accuracy (%RE ranged from −1.8% to 5.0% (LLOQ ±16.5%. The total analysis time was 3.0 min. The method was fully validated and successfully applied to a pharmacokinetic study of melatonin prolonged-release tablet in Beagle dogs. The values of half-life and Tmax were similar to the corresponding data reported before.

Flow rate dependent extra-column variance from injection in capillary liquid chromatography.

Science.gov (United States)

Aggarwal, Pankaj; Liu, Kun; Sharma, Sonika; Lawson, John S; Dennis Tolley, H; Lee, Milton L

2015-02-06

Efficiency and resolution in capillary liquid chromatography (LC) can be significantly affected by extra-column band broadening, especially for isocratic separations. This is particularly a concern in evaluating column bed structure using non-retained test compounds. The band broadening due to an injector supplied with a commercially available capillary LC system was characterized from experimental measurements. The extra-column variance from the injection valve was found to have an extra-column contribution independent of the injection volume, showing an exponential dependence on flow rate. The overall extra-column variance from the injection valve was found to vary from 34 to 23 nL. A new mathematical model was derived that explains this exponential contribution of extra-column variance on chromatographic performance. The chromatographic efficiency was compromised by ∼130% for a non-retained analyte because of injection valve dead volume. The measured chromatographic efficiency was greatly improved when a new nano-flow pumping system with integrated injection valve was used. Copyright © 2014 Elsevier B.V. All rights reserved.

High performance liquid chromatographic separation of beryllium from some transition metals produced in high energy proton irradiations of medium mass elements: measurement of (p,7Be) cross sections

International Nuclear Information System (INIS)

Fassbender, M.; Spellerberg, S.; Qaim, S.M.

1996-01-01

A high performance liquid chromatographic (HPLC) method was developed for the separation of 7 Be formed in high energy proton irradiation of medium mass elements like Fe, Cu etc. The bulk of the target material was removed in a preseparation step. Thereafter beryllium was obtained in a high purity within a few minutes elution time using a mixture of 5 mM citric acid and 1.0 mM pyridinedicarboxylic acid as eluent and a SYKAM KO2 analytical cation-exchange column. The effect of Be-carrier on the quality of separation was investigated. The quality of separation deteriorated with the increasing Be-carrier column loading. A certain amount of Be-carrier was, however, necessary in order to quantitate the results. By using low Be-carrier amounts (∝100 μg) and determining the elution yield via a conductometric method, it was possible to obtain quantitative separation results. Besides the analytical column, a semi-preparative column was also used, and the Be separation yield determined gravimetrically. The cross sections for the (p, 7 Be) process on Cu obtained using the two separation columns (analytical and semipreparative) and the two separation yield determination methods agreed within 15%. (orig.)

Development of a validated liquid chromatographic method for quantification of sorafenib tosylate in the presence of stress-induced degradation products and in biological matrix employing analytical quality by design approach.

Science.gov (United States)

Sharma, Teenu; Khurana, Rajneet Kaur; Jain, Atul; Katare, O P; Singh, Bhupinder

2018-05-01

The current research work envisages an analytical quality by design-enabled development of a simple, rapid, sensitive, specific, robust and cost-effective stability-indicating reversed-phase high-performance liquid chromatographic method for determining stress-induced forced-degradation products of sorafenib tosylate (SFN). An Ishikawa fishbone diagram was constructed to embark upon analytical target profile and critical analytical attributes, i.e. peak area, theoretical plates, retention time and peak tailing. Factor screening using Taguchi orthogonal arrays and quality risk assessment studies carried out using failure mode effect analysis aided the selection of critical method parameters, i.e. mobile phase ratio and flow rate potentially affecting the chosen critical analytical attributes. Systematic optimization using response surface methodology of the chosen critical method parameters was carried out employing a two-factor-three-level-13-run, face-centered cubic design. A method operable design region was earmarked providing optimum method performance using numerical and graphical optimization. The optimum method employed a mobile phase composition consisting of acetonitrile and water (containing orthophosphoric acid, pH 4.1) at 65:35 v/v at a flow rate of 0.8 mL/min with UV detection at 265 nm using a C 18 column. Response surface methodology validation studies confirmed good efficiency and sensitivity of the developed method for analysis of SFN in mobile phase as well as in human plasma matrix. The forced degradation studies were conducted under different recommended stress conditions as per ICH Q1A (R2). Mass spectroscopy studies showed that SFN degrades in strongly acidic, alkaline and oxidative hydrolytic conditions at elevated temperature, while the drug was per se found to be photostable. Oxidative hydrolysis using 30% H 2 O 2 showed maximum degradation with products at retention times of 3.35, 3.65, 4.20 and 5.67 min. The absence of any

Determination of Picloram in Soil and Water by Reversed-Phase Liquid Chromatography

Science.gov (United States)

M.J.M. Wells; J.L. Michael; D.G. Neary

1984-01-01

A reversed-phase liquid chromatographic method is presneted for the determination of picloram in the parts per billion (ppb) range in soil, soil solution, and stream samples. Quanitification is effected by UV absorpation at 254 nm. Derivatization is not necessary. The method permits 92% ± 7.1 recovery from water samples and 61.8% ± 11.1 recovery from soil samples....

Rapid, simple and highly sensitive LC-ESI-MS/MS method for the quantification of tamsulosin in human plasma.

Science.gov (United States)

Ramakrishna, N V S; Vishwottam, K N; Manoj, S; Koteshwara, M; Wishu, S; Varma, D P

2005-12-01

A simple, rapid, sensitive and specific liquid chromatography-tandem mass spectrometry method was developed and validated for quantification of tamsulosin (I), a highly selective alpha1-adrenoceptor antagonist used for the treatment of patients with symptomatic benign prostatic hyperplasia. The analyte and internal standard, mosapride (II) were extracted by liquid-liquid extraction with diethyl ether-dichloromethane (70:30, v/v) using a Glas-Col Multi-Pulse Vortexer. The chromatographic separation was performed on a reverse phase Waters symmetry C18 column with a mobile phase of 0.03% formic acid-acetonitrile (30:70, v/v). The protonated analyte was quantitated in positive ionization by multiple reaction monitoring with a mass spectrometer. The mass transitions m/z 409.1 solidus in circle 228.1 and m/z 422.3 solidus in circle 198.3 were used to measure I and II, respectively. The assay exhibited a linear dynamic range of 0.1-50.0 ng/mL for tamsulosin in human plasma. The lower limit of quantitation was 100 pg/mL with a relative standard deviation of less than 10%. Acceptable precision and accuracy were obtained for concentrations over the standard curve ranges. A run time of 2.0 min for each sample made it possible to analyze a throughput of more than 400 human plasma samples per day. The validated method has been successfully used to analyze human plasma samples for application in pharmacokinetic, bioavailability or bioequivalence studies. (c) 2005 John Wiley & Sons, Ltd.

Chromatographic monitoring procedures in laboratory practice

Energy Technology Data Exchange (ETDEWEB)

Kaplina, E G; Belova, O I; Lasunina, N A

1976-01-01

The Moscow Coke and Chemical Works consist of three plants in combination, viz., the coking plant, the synthetic ammonia plant using coke-oven-gas hydrogen and the oxygen plant. The plant requirements include daily analyses not only of the coke-oven gas but also of a rich gas and an ethylene fraction. The analyses are carried out in VTI-2 apparatus. The analytical data are used to calculate the calorific values and densities of the gases. The time requirements are very considerable and the laboratory has long been engaged in developing and introducing chromatographic procedures for the major constituents of coke-oven gas, rich gas and ethylene fraction. The procedure developed for the coke-oven and rich gases uses two parallel columns, one packed with molecular sieves and the other with grade KSM silica gel. Hydrogen was determined with argon as the carrier gas, and all other constituents with helium. The procedure was time-consuming and complicated. An attempt was made to separate the gases in an LKhM-7a chromatograph with a programme-controlled 50 to 250/sup 0/C heating cycle, but the procedure still had a number of serious defects and could not be recommended for regular quality control. The final variant involved two parallel columns and a procedure based on that in GOST 14920 (''Dry gas. Proximate analysis''). The chromatograph was a type KhL-69 with a 6-way cock in the gas line so that each of the columns could be brought on stream in succession. The analytical column packings were zeolite (in a 2 m column) and diatomaceous brick with 25% n-hexadecane (in a 6 m column).

Rapid Determination of Amino Acids in Beer, Red Wine, and Donkey-Hide Gelatin by Gradient Elution of HPLC: From Micellar Liquid Chromatography to High Submicellar Liquid Chromatography.

Science.gov (United States)

Xie, Yunfei; Luo, Tian; Yang, Jing; Dong, Yuming

2018-01-01

Amino acids (AAs) in beer, red wine, and donkey-hide gelatin were rapidly determined by gradient LC elution from micellar LC to high submicellar LC. Mobile phase A was a 0.075 M sodium dodecyl sulfate solution containing 20 mM ammonium acetate with a pH value adjusted to 3.5 with acetic acid solution, and mobile phase B was acetonitrile. Optimized chromatographic conditions were as follows: mobile phase B increased from 25 to 60% (v/v) in 30 min and the use of a Venusil XBP C18 column (5 µm, 250 × 4.6 mm) as the stationary phase, with a column temperature of 35°C, flow rate of 1.2 mL/min, and detection wavelength of 266 nm. The results indicated good linearity (r2 ≥ 0.9924). The intraday precision of the retention time was RSD ≤ 1.1%, whereas interday was RSD ≤ 3.2%; intraday precision of the peak area was RSD ≤ 3.3%, whereas interday was RSD ≤ 4.9%. The range of recovery was 94.6-102.4%. The RSDs of the retention time for the AAs for the different samples were 0.04-0.31%.

Use of coextraction and suppression of extraction in extraction-chromatographic separation of elements

International Nuclear Information System (INIS)

Karandashev, V.K.; Kuznetsov, R.A.; Grazhulene, S.S.; Usmanova, M.M.

1988-01-01

TBP, solutions of hydrobromic acid, indium and polytetrafluoroethylene powder, carrier for TBP, were used to study the effects of coextraction and extraction suppression on extraction-chromatographic behaviour of microamounts of elements in the presence of macroamounts of other elements. Possibility of using these effects under extraction-chromatographic element separation were considered. A new method for extraction-chromatographic separation of scandium microamounts from the mixture of large amount of elements (Y, Cd, Ce, Eu, Lu, Hf, Ta, W, Np and other) was suggested. 15 refs.; 3 figs

Liquid-vapour surface sensors for liquid nitrogen and hydrogen

Science.gov (United States)

Siegwarth, J. D.; Voth, R. O.; Snyder, S. M.

1992-01-01

The present paper identifies devices to serve as liquid-vapor detectors in zero gravity. The testing in LH2 was done in a sealed glass Dewar system to eliminate any chance of mixing H2 and air. Most of the tests were performed with the leads to the sensor horizontal. Some results of rapid cycle testing of LVDG in LH2 are presented. Findings of rapid-cycle testing of LVDG in LH2 are discussed. The sensor crossed the liquid surface when the position sensor registered 1.9 V, which occurred at about 0.4075 s. The delay time was about 1.5 ms. From the estimated slope of the position sensor curve at 1.9 V, the velocity of the sensor through the liquid surface is over 3 m/s. Results of tests of optical sensors are presented as well.

Room-temperature saturated ferroelectric polarization in BiFeO3 ceramics synthesized by rapid liquid phase sintering

International Nuclear Information System (INIS)

Wang, Y.P.; Zhou, L.; Zhang, M.F.; Chen, X.Y.; Liu, J.-M.; Liu, Z.G.

2004-01-01

Single-phased ferroelectromagnet BiFeO 3 ceramics with high resistivity were synthesized by a rapid liquid phase sintering technique. Saturated ferroelectric hysteresis loops were observed at room temperature in the ceramics sintered at 880 deg. C for 450 s. The spontaneous polarization, remnant polarization, and the coercive field are 8.9 μC/cm 2 , 4.0 μC/cm 2 , and 39 kV/cm, respectively, under an applied field of 100 kV/cm. It is proposed that the formation of Fe 2+ and an oxygen deficiency leading to the higher leakage can be greatly suppressed by the very high heating rate, short sintering period, and liquid phase sintering technique. The latter was also found effective in increasing the density of the ceramics. The sintering technique developed in this work is expected to be useful in synthesizing other ceramics from multivalent or volatile starting materials

Ion Chromatographic Analyses of Sea Waters, Brines and Related Samples

OpenAIRE

Nataša Gros

2013-01-01

This review focuses on the ion chromatographic methods for the analyses of natural waters with high ionic strength. At the beginning a natural diversity in ionic composition of waters is highlighted and terminology clarified. In continuation a brief overview of other review articles of potential interest is given. A review of ion chromatographic methods is organized in four sections. The first section comprises articles focused on the determination of ionic composition of water samples as com...

Determination of Arctiin and Arctigenin Contents in Arctium Tomentosum Mill. by HPLC Method

OpenAIRE

Xiaoying Zhou; Haoke Zhang; Liang Ge; Haiyan Gong; Shuge Tian

2011-01-01

A simple, precise, rapid and accurate, binary-phase high performance liquid chromatographic method has been developed for the determination of arctiin and arctigenin contents in the Arctium tomentosumMill. with short run time. Chromatographic separation was achieved by using HPLC system, consisting of a Shimadzu LC-6AD and Kromasil C18 column (250×4.6 mm, 5 μm, with pre-column), the mobile phase consists of methanol and water (55: 45). Detection wavelength was 280 nm. The speed of flow was 1....

Stability-Indicating RP-HPLC Method for Analysis of Paracetamol and Tramadol in a Pharmaceutical Dosage Form

OpenAIRE

Kamble, Rajesh M.; Singh, Shrawan G.

2012-01-01

A simple, isocratic, rapid and accurate reversed phase high performance liquid chromatography method was developed for the quantitative determination of paracetamol and tramadol in commercial medicinal tablets. The chromatographic separation was achieved on an Intersil C18 (250 mm x 4.6 mm, 5μm) column using water pH 3.4 with orthophosphoric acid: methanol (60:40, v/v) as a mobile phase, and UV detection at 228 nm. The chromatographic resolutions between paracetamol and tramadol were found gr...

Rapid method to determine actinides and 89/90Sr in limestone and marble samples

International Nuclear Information System (INIS)

Maxwell, S.L.; Culligan, Brian; Hutchison, J.B.; Utsey, R.C.; Sudowe, Ralf; McAlister, D.R.

2016-01-01

A new method for the determination of actinides and radiostrontium in limestone and marble samples has been developed that utilizes a rapid sodium hydroxide fusion to digest the sample. Following rapid pre-concentration steps to remove sample matrix interferences, the actinides and 89 / 90 Sr are separated using extraction chromatographic resins and measured radiometrically. The advantages of sodium hydroxide fusion versus other fusion techniques will be discussed. This approach has a sample preparation time for limestone and marble samples of <4 h. (author)

Rapid response sensor to monitor the temperature and flow of liquid metals

International Nuclear Information System (INIS)

McCann, J.D.

1980-01-01

Two forms of a sensor capable of simultaneously monitoring the temperature and flow of liquid metal coolants within a reactor are described. They operate by measuring the coupling impedances between the sensor and the surrounding electrically conductive coolant. Since the system utilises electrical rather than thermal properties, the response to perturbations is rapid, typically displaying the changed conditions within a few milliseconds. The first form of the sensor was designed to operate whilst protected by a thick walled service tube positioned in the reactor coolant. Providing bends in the tube had a radius greater than 70 cm, the sensor could be removed for inspection and maintenance if necessary. The second sensor was fitted inside a streamlined NaK proof capsule. This was inserted directly into the coolant outlet stream of a fuel pin assembly in the Dounreay Fast Reactor. In this form the sensor successfully monitored flow, entrained gas and temperature excursions during the final operating cycle of D.F.R. (author)

Chromatographic decontamination of medium-activity waste concentrates

International Nuclear Information System (INIS)

Faubel, W.; Menzler, P.M.; Sameh, A.A.

1988-01-01

The chromatographic decontamination of a MAW concentrate was carried out in a laboratory plant in 1-l-batches in the following way: In order to purify the nitric MAW concentrate from its solid and organic contamination products, it is passed through a filter and an absorber (SM7) for organic species. Subsequently the purified solution runs on-line through all following columns. First the main activity carrier cesium ( 137 Cs, 134 Cs) is transferred to ammonium molybdate phosphate (AMP-1) by means of a newly developed fluidized bed process. In the further course, 125 Sb is separated on metal oxides (Sb 2 O 5 , MnO 2 ) and the three-valued actinides/lanthanides on an extraction-chromatographic CMPO column. Finally the remaining 106 Ru and 60 Co activities are separated on dimethylglyoximes (DMG) coated on active carbon. (orig./RB) [de

Determination of descriptors for polycyclic aromatic hydrocarbons and related compounds by chromatographic methods and liquid-liquid partition in totally organic biphasic systems.

Science.gov (United States)

Ariyasena, Thiloka C; Poole, Colin F

2014-09-26

Retention factors on several columns and at various temperatures using gas chromatography and from reversed-phase liquid chromatography on a SunFire C18 column with various mobile phase compositions containing acetonitrile, methanol and tetrahydrofuran as strength adjusting solvents are combined with liquid-liquid partition coefficients in totally organic biphasic systems to calculate descriptors for 23 polycyclic aromatic hydrocarbons and eighteen related compounds of environmental interest. The use of a consistent protocol for the above measurements provides descriptors that are more self consistent for the estimation of physicochemical properties (octanol-water, air-octanol, air-water, aqueous solubility, and subcooled liquid vapor pressure). The descriptor in this report tend to have smaller values for the L and E descriptors and random differences in the B and S descriptors compared with literature sources. A simple atom fragment constant model is proposed for the estimation of descriptors from structure for polycyclic aromatic hydrocarbons. The new descriptors show no bias in the prediction of the air-water partition coefficient for polycyclic aromatic hydrocarbons unlike the literature values. Copyright © 2014 Elsevier B.V. All rights reserved.

Analysis of Nitro-aromatic and Nitramine Explosives by Atmospheric Pressure Chemical Ionization / High Performance Liquid Chromatography / Mass Spectrometry / Mass Spectrometry

International Nuclear Information System (INIS)

Hicks, B.J.; Han, W.; Robben, J.R.

2009-01-01

This procedure is capable of separating and quantifying twenty-nine high explosives and internal surrogates with a single injection. After the initial preparation step, the sample is introduced to the high performance liquid chromatograph for target separation, ionized by atmospheric pressure chemical ionization and the explosives of interest are isolated / quantified by mass spectrometry / mass spectrometry. Concentrations of the target explosives are measured relative to the response of both internal and external standard concentrations. A C-18 reverse phase high performance liquid chromatograph column is used for separation. Ionization is performed using both positive and negative atmospheric pressure chemical ionization resulting in a molecular ion with little fragmentation. These ions are isolated at the first quadrupole of the mass spectrometer, dissociated by collision with argon in the collision cell and the resulting daughter ions are isolated at the second quadrupole. These daughter ions then reach the detector where they are quantified. To date this procedure represents the most thorough high performance liquid chromatography / mass spectrometry / mass spectrometry explosives analysis available in the environmental chemistry market. (authors)

Leukotriene B4 catabolism: quantitation of leukotriene B4 and its omega-oxidation products by reversed-phase high-performance liquid chromatography.