A New Approach to the Study of Glucosinolates by Isocratic Liquid Chromatography. Part I. Rapid Determination of Desulfated Derivatives of Rapeseed Glucosinolates

1991 ◽  
Vol 74 (6) ◽  
pp. 932-939
Author(s):  
Alain Quinsac ◽  
Daniel Ribaillier ◽  
Claire Elfakir ◽  
Michel Lafosse ◽  
Michel Dreux
Keyword(s):  
Rapid Determination ◽  
Stationary Phases ◽  
New Approach ◽  
Wild Mustard ◽  
Relative Standard ◽  
Comparison Of The Results ◽  
Liquid Chromatographic ◽  
Derivatives Of ◽  
Better Than

Abstract Liquid chromatographic (LC) analysis of desulfated derivatives of rapeseed glucosinolates has been carried out under isocratic elution conditions with different CN-bonded stationary phases. The effects of the eluant composition (water, acetonitrile, and methanol) with the stationary phase (Zorbax CN, Lichrospher CN, and Ultrasphere CN) and temperature (20 and 50°C) are described. An isocratic LC method performed at room temperature using a Lichrospher CN column and water as mobile phase is proposed. The chromatographic analysis can be done in less than 12 min, and it is easier and less expensive than the traditional gradient mode. Four commercial samples of rapeseed containing various quantities of other cruciferous seeds (wild mustard and stinkweed) as an admixture have been analyzed to determine the total giucosinolate content. Relative standard deviations of repeatability of the isocratic and gradient LC methods ranged from 0.4 to 1.7% and from 2.7 to 4.7%, respectively. Comparison of the results showed good agreement between the 2 methods (better than 98%).

Liquid Chromatographic Determination of Ochratoxin A in Coffee Beans and Coffee Products

1986 ◽  
Vol 69 (6) ◽  
pp. 960-964 ◽  
Author(s):  
Hisaya Terada ◽  
Haruo Tsubouchi ◽  
Katsuhiko Yamamoto ◽  
Kazuo Hisada ◽  
Yoshio Sakabe
Keyword(s):  
Ochratoxin A ◽  
Chromatographic Determination ◽  
Instant Coffee ◽  
Coffee Beans ◽  
Liquid Chromatographic Method ◽  
Relative Standard ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic ◽  
Better Than

Abstract A liquid chromatographic method for the determination of ochratoxin A in coffee beans (green and roast), instant coffee, and coffee drink is described. The sample is subjected to extraction with methanol-1% aqueous sodium bicarbonate (1 + 1) and C18 cartridge cleanup. The extract is chromatographed on a Nucleosil 5C18 column with a mobile solvent of acetonitrile-water-0.2M phosphate buffer pH 7.5 (50 + 47 + 3) containing 3mM cetyltrimethylammonium bromide as an ionpair reagent. Ochratoxin A is detected with a fluoromcter (excitation 365 nm, emission 450 nm). The sensitivity was increased 20-fold by using ion-pair resolution. The detection limits corresponded to 2 μg/kg for coffee beans, 5 μg/kg for instant coffee, and 0.2 μg/kg for coffee drink. The recoveries from coffee products were generally better than 80.7% and the relative standard deviations were 3.43-5.93%. The peak coinciding with ochratoxin A can be confirmed by treatment using alcohol (methanol, ethanol, or n-propanol) and H2S04.

scholarly journals Validation of a Method for Determination of Phospholipase A2 and Melittin in Bee Venom Preparations by Capillary Electrophoresis

2000 ◽  
Vol 83 (3) ◽  
pp. 549-554 ◽  
Author(s):  
Vêa Pacáková ◽  
Karel Ŝtulík
Keyword(s):  
Phospholipase A2 ◽  
Correlation Coefficients ◽  
Bee Venom ◽  
Uv Detector ◽  
Irreversible Adsorption ◽  
Relative Standard ◽  
Main Components ◽  
Liquid Chromatographic ◽  
Better Than

Abstract A method was validated for the determination of the 2 main components of bee venom, phospholipase A2 and melittin, by capillary electrophesis (CE). Optimum resolution and selectivity were attained with a running electrolyte of 150 mM phosphoric acid, pH 1.8. The repeatability and day-to-day reproducibility of the migration times were better than 0.36 and 2.8%, respectively. The repeatability and day-to-day reproducibility of the normalized peak areas were better than 1.3 and 2.6%, respectively. The response of the UV detector at 190 nm was linear over < 2 concentration decades, from 0.05 to 1.5 mg/mL, with correlation coefficients of 0.9994 for phospholipase A2 and 0.9997 for melittin. The limits of detection and quantitation were 4.5 and 15 μg/mL, respectively, for phospholipase A2 and 1.6 and 6 μg/mL, respectively, for melittin. The reproducibility of the measurements with 2 different CE instruments was satisfactory; the mean concentration and relative standard deviation (RSD) values for phospholipase A2 and melittin were 14.4% (RSD, 1.3%) and 51.4% (RSD, 1.1%), respectively, with instrument I; the corresponding values with instrument II were 14.5% (RSD, 2.8%) and 52.3% (RSD, 2.2%). The accuracy was estimated by comparison with a liquid chromatographic (LC) method. Differences between the CE and LC measurements were attributed to irreversible adsorption of the analytes on the LC column. The recoveries of phospholipase A2 and melittin with the CE method were 98.8 and 101.7%, respectively.

Rapid Determination of Deoxynivalenol (Vomitoxin) by Liquid Chromatography Using Modified Romer Column Cleanup

1984 ◽  
Vol 67 (1) ◽  
pp. 52-54 ◽  
Author(s):  
Henry L Chang ◽  
Jonathan W Devries ◽  
Paul A Larson ◽  
Hasmukh H Patel
Keyword(s):  
Liquid Chromatography ◽  
Standard Deviation ◽  
Mobile Phase ◽  
Rapid Determination ◽  
Alumina Column ◽  
Relative Standard ◽  
Alumina Column Chromatography ◽  
Wheat Products ◽  
Liquid Chromatographic

Abstract A modification of the Romer method for determining deoxynivalenol (DON) provides rapid sample cleanup and includes liquid chromatographic (LC) quantitation. The method was evaluated using wheat, wheat flour, and other wheat products. The sample is extracted with acetonitrile–water (84 + 16), and an aliquot of the extract is subjected to activated charcoal–alumina column chromatography. The extract is then evaporated and diluted to volume with mobile phase, and DON is quantitated using liquid chromatography. The relative standard deviation based on duplicate samples is 6.07%. The detection limit is 30 ppb based on 2 x signal/noise ratio. Results by this method compared with the results obtained by the Scott GC method showed a correlation coefficient of 0.992 with a mean vomitoxin content of 779 ppb by this method and 716 ppb by the Scott method for 14 samples.

scholarly journals Development and Validation of Enantiomeric Purity of Montelukast by SFC Method on Amylose Based Stationary Phase

2008 ◽  
Vol 4 (3) ◽  
pp. 518-524
Author(s):  
Vijaya Lakshmi Maddala ◽  
Kameswararao Ch ◽  
Srinivasulu Polisetty ◽  
Sai Venkata Srinivas Koduri ◽  
P.C. Ray
Keyword(s):  
Supercritical Fluid ◽  
Mobile Phase ◽  
Enantiomeric Purity ◽  
Phase System ◽  
Relative Standard ◽  
Peak Areas ◽  
Development And Validation ◽  
Liquid Chromatographic ◽  
Better Than

A new Supercritical fluid liquid chromatographic (SFC) method has been developed in normal-phase conditions for the determination of enantiomeric purity of Montelukast sodium (S,E)-2-(1-((1-3-(2-(7-chloroquinolin-2-yl)vinyl)phenyl)-3-(2-(2-hydroxypropan-2-yl)phenyl)propylthio)ethyl) cyclopropyl) acetic acid (R-isomer) (Anti asthmatic drug) in bulk drugs and in dosage forms. The sample was screened on the analytical SFC to determine the best column for the separation. The screening conditions are Column: Chiralpak AS-H (250 mm x 4.6 mm, 5 μm) column using a mobile phase system containing Supercritical fluid (Co2) and 2-Propanol in the ratio (85:15% v/v). The mobile-phase compositions and the differences in separation capability of the method is noted. The resolution between two enantiomers is found to be greater than 1.5. The SFC method for the separation of enantiomers of Montelukast is proved Accurate, Precise, Linear and robust. Relative standard deviation of retention times and peak areas were better than 0.2% and 0.4%, respectively, for precision. 

Electron-capture gas-liquid chromatographic determination of ethosuximide and desmethylmethsuximide in plasma or serum.

1979 ◽  
Vol 25 (2) ◽  
pp. 252-255 ◽  
Author(s):  
J E Wallace ◽  
H A Schwertner ◽  
H E Hamilton ◽  
E L Shimek
Keyword(s):  
Electron Capture ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Salting Out ◽  
Liquid Chromatograph ◽  
Relative Standard ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic ◽  
Derivatives Of

Abstract We describe the determination of ethosuximide and desmethylmethsuximide, simultaneously or separately, in 50 to 100 microliter of plasma or serum. Derivatives of ethosuximide and desmethylmethsuximide formed by reaction with pentafluorobenzoyl chloride are extremely sensitive to the electron-capture detector of a gas-liquid chromatograph. The sample, with added internal standard and ammonium sulfate as a pH-adjusting and salting-out agent, is extracted with ethyl acetate/benzene (20/80 by vol). The extract is evaporated and the derivatives are formed. Analytical recoveries of ethosuximide and desmethylmethsuximide exceed 99%, and the relative standard deviation (CV) between analyses is usually less than 4.0%. alpha-Methyl-alpha-propylsuccinimide is used as the internal standard for ethosuximide, 2-phenylsuccinimide as the internal standard for desmethylmethsuximide.

Development and Validation of Enantiomeric Purity of Montelukast by SFC Method on Amylose Based Stationary Phase

2013 ◽  
Vol 12 (7) ◽  
pp. 518-524
Author(s):  
Vijaya Lakshmi Maddala ◽  
Kameswararao Ch ◽  
Srinivasulu Polisetty
Keyword(s):  
Supercritical Fluid ◽  
Mobile Phase ◽  
Enantiomeric Purity ◽  
Phase System ◽  
Relative Standard ◽  
Peak Areas ◽  
Development And Validation ◽  
Liquid Chromatographic ◽  
Better Than

A new Supercritical fluid liquid chromatographic (SFC) method has been developed in normal-phase conditions for the determination of enantiomeric purity of Montelukast sodium (S,E)-2-(1-((1-3-(2-(7-chloroquinolin-2-yl)vinyl)phenyl)-3-(2-(2-hydroxypropan-2-yl)phenyl)propylthio)ethyl) cyclopropyl) acetic acid (R-isomer) (Anti asthmatic drug) in bulk drugs and in dosage forms. The sample was screened on the analytical SFC to determine the best column for the separation. The screening conditions are Column: Chiralpak AS-H (250 mm x 4.6 mm, 5 μm) column using a mobile phase system containing Supercritical fluid (Co2) and 2-Propanol in the ratio (85:15% v/v). The mobile-phase compositions and the differences in separation capability of the method is noted. The resolution between two enantiomers is found to be greater than 1.5. The SFC method for the separation of enantiomers of Montelukast is proved Accurate, Precise, Linear and robust. Relative standard deviation of retention times and peak areas were better than 0.2% and 0.4%, respectively, for precision. 

Stability Indicating Liquid Chromatographic Method for the Determination of Fenofibrate and its Application to Kinetic Studies

2013 ◽  
Vol 5 (4) ◽  
pp. 1866-1874
Author(s):  
K. Srinivasa Rao ◽  
Keshar N K ◽  
N Jena ◽  
M.E.B Rao ◽  
A K Patnaik
Keyword(s):  
Degradation Products ◽  
Kinetic Studies ◽  
Pharmaceutical Formulations ◽  
Assay Method ◽  
Pharmaceutical Dosage Form ◽  
Stability Indicating ◽  
Zero Order Kinetics ◽  
Relative Standard ◽  
Liquid Chromatographic

A stability-indicating LC assay method was developed for the quantitative determination of fenofibrate (FFB) in pharmaceutical dosage form in the presence of its degradation products and kinetic determinations were evaluated in acidic, alkaline and peroxide degradation conditions. Chromatographic separation was achieved by use of Zorbax C18 column (250 × 4.0 mm, 5 μm). The mobile phase was established by mixing phosphate buffer (pH adjusted 3 with phosphoric acid) and acetonitrile (30:70 v/v). FFB degraded in acidic, alkaline and hydrogen peroxide conditions, while it was more stable in thermal and photolytic conditions. The described method was linear over a range of 1.0-500 μg/ml for determination of FFB (r= 0.9999). The precision was demonstrated by relative standard deviation (RSD) of intra-day (RSD= 0.56– 0.91) and inter-day studies (RSD= 1.47). The mean recovery was found to be 100.01%. The acid and alkaline degradations of FFB in 1M HCl and 1M NaOH solutions showed an apparent zero-order kinetics with rate constants 0.0736 and 0.0698  min−1 respectively and the peroxide degradation with 5% H2O2 demonstrated an apparent first-order kinetics with rate constant k = 0.0202 per min. The t1/2, t90   values are also determined for all the kinetic studies. The developed method was found to be simple, specific, robust, linear, precise, and accurate for the determination of FFB in pharmaceutical formulations.  

Gas-Liquid Chromatographic Determination of Technical Chlordane Residues in Food Crops: Interpretation of Analytical Data

1975 ◽  
Vol 58 (5) ◽  
pp. 1051-1061
Author(s):  
William P Cochrane ◽  
James F Lawrence ◽  
Young W Lee ◽  
Ronald B Maybury ◽  
Brian P Wilson
Keyword(s):  
Field Experiments ◽  
Stationary Phases ◽  
Analytical Data ◽  
Chromatographic Determination ◽  
Electron Capture Detection ◽  
Food Crops ◽  
Liquid Chromatographic Determination ◽  
Consistent Method ◽  
Liquid Chromatographic

Abstract An interlaboratory investigation of technical chlordane residues in food crops was carried out to determine the most practical and consistent method of reporting results. Using a technical chlordane reference standard, 8 gas chromatographic stationary phases were studied for their resolution capabilities. The best separations were obtained with SE-30 and its OV-1 equivalent. Using these columns and electron capture detection, potatoes and carrots from supervised field experiments were analyzed in duplicate and quantitated by using 4 methods of calculation. The data were statistically treated to determine the precision and bias for each method. Also, 1 sample was analyzed in duplicate on 2 different occasions by 6 laboratories to substantiate the initial conclusions. Based on the criterion of high precision it is suggested that a comparison of total area under the chromatogram of the sample with total area of a standard technical chlordane be the method of quantitation. Only peaks which are common to both standard and sample have any significance in this type of calculation.

scholarly journals Rapid Determination of Ethylene Oxide and 75 VOCs in Ambient Air with Canister Sampling and Associated Growth Issues

Separations ◽  
2021 ◽  
Vol 8 (3) ◽  
pp. 35
Author(s):  
Jason Hoisington ◽  
Jason S. Herrington
Keyword(s):  
Ethylene Oxide ◽  
Rapid Determination ◽  
Complex Mixture ◽  
Ambient Air ◽  
Gas Chromatography Mass Spectrometry ◽  
Average Accuracy ◽  
Relative Standard ◽  
Wide Range ◽  
Us Epa

A canister-based sampling method along with preconcentrator-Gas chromatography-Mass Spectrometry (GC-MS) analysis was applied to ethylene oxide (EtO or EO) and 75 other volatile organic compounds (VOCs) in ambient air. Ambient air can contain a large variety of VOCs, and thorough analysis requires non-discriminatory sampling and a chromatographic method capable of resolving a complex mixture. Canister collection of whole air samples allows for the collection of a wide range of volatile compounds, while the simultaneous analysis of ethylene oxide and other VOCs allows for faster throughput than separate methods. The method presented is based on US EPA Method TO-15A and allows for the detection of EtO from 18 to 2500 pptv. The method has an average accuracy of 104% and precision of 13% relative standard deviation (RSD), with an instrument run time of 32 min. In addition, a link between canister cleanliness and ethylene oxide growth is observed, and potential mechanisms and cleaning strategies are addressed.

scholarly journals Application of Liquid Chromatography to the Simultaneous Determination of Acetylsalicylic Acid, Caffeine, Codeine, Paracetamol, Pyridoxine, and Thiamine in Pharmaceutical Preparations

2001 ◽  
Vol 84 (3) ◽  
pp. 676-683 ◽  
Author(s):  
Natividad Ramos-Martos ◽  
Francisco Aguirre-Gómez ◽  
Antonio Molina-Díaz ◽  
Luis F Capitán-Vallvey
Keyword(s):  
Salicylic Acid ◽  
Acetylsalicylic Acid ◽  
Simultaneous Determination ◽  
Pharmaceutical Preparations ◽  
Reversed Phase ◽  
Liquid Chromatographic Method ◽  
Relative Standard ◽  
Phase Liquid ◽  
Liquid Chromatographic

Abstract This paper describes a rapid reversed-phase liquid chromatographic method, with UV detection, for the simultaneous determination of acetylsalicylic acid, caffeine, codeine, paracetamol, pyridoxine, and thiamine in pharmaceutical preparations. A reversed-phase C18 Nucleosil column is used. The mobile phase consists of 2 successive eluants: water (5 min) and acetonitrile–water (75 + 25, v/v; 9 min), both adjusted to pH 2.1 with phosphoric acid. Before determination acetylsalicylic acid is completely converted to salicylic acid by alkaline hydrolysis. Salicylic acid, caffeine, paracetamol, pyridoxine, and thiamine are all detected at 285 nm, whereas codeine is detected at 240 nm. Calibration curves were linear for salicylic acid, caffeine, paracetamol, and pyridoxine in the range of 50–500 mg/L, and for codeine and thiamine in the range of 50–1000 mg/L. The method was applied to the analysis of 13 fortified commercial pharmaceutical preparations. Recoveries ranged from 92.6 to 105.5%, with relative standard deviations of 1.1–5.8%.

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