Gas-Liquid Chromatographic Determination of C22 Fatty Acids for the Certification of Low Erucic Acid Varieties of Rapeseeds

1976 ◽  
Vol 59 (4) ◽  
pp. 855-858
Author(s):  
Jean P Barrette
Keyword(s):  
Fatty Acids ◽  
Erucic Acid ◽  
Methyl Esters ◽  
Chromatographic Determination ◽  
Detector Response ◽  
Check Sample ◽  
Liquid Chromatographic Determination ◽  
Low Erucic Acid ◽  
Liquid Chromatographic

Abstract A rapid gas-liquid chromatographic (GLC) procedure was developed for the determination of C22 fatty acids (mostly erucic acid) in rapeseeds containing less than 5% erucic acid. The method involves an oil extraction from a representative sample of rapeseeds, a vigorous boron trifluoride-methanol transesterification of the oil to methyl esters, and analysis by GLC with the aid of an electronic integrator. Six laboratories participated in a monthly check sample program. By adjusting the GLC detector response with 2 synthetic reference standard mixtures containing 1.0 and 3.0% methyl behenate, interlaboratory agreement within 0.3% C22 was consistently obtained.

Gas-Liquid Chromatographic Determination of Sucrose Fatty Acid Esters

1983 ◽  
Vol 66 (4) ◽  
pp. 1050-1052
Author(s):  
Taizo Tsuda ◽  
Hiroshi Nakanishi
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Methyl Esters ◽  
Chromatographic Determination ◽  
Fatty Acid Esters ◽  
Liquid Chromatographic Determination ◽  
Sucrose Fatty Acid Esters ◽  
Liquid Chromatographic ◽  
Acid Esters

Abstract A method was developed for gas-liquid chromatographic determination of sucrose fatty acid esters as TMS derivative of sucrose and methyl esters of fatty acids. Sucrose fatty acid esters were completely degraded to sucrose and fatty acids in alkaline ethanol overnight at 25°C. Sucrose was derivatized with pyridine, trimethylchlorosilane, and N-trimethylsilylimidazole and the sucrose TMS derivative was determined on a 2% OV-17 column. Fatty acids were extracted with ethyl ether, methylated with BF3-methanol complex at 65°C, and determined on a 2% DEGS + 0.5% H3PO4 column. This method was applied to selected sucrose fatty acid esters. For example, sucrose and fatty acids derived from 50 mg sample F20 were 10.6-11.0 and 38.1-39.0 mg, respectively. Total amounts were 48.7-50.0 mg with a standard deviation of 0.4 (n = 6).

Optimized liquid-chromatographic determination of metronidazole and its metabolites in plasma.

1984 ◽  
Vol 30 (5) ◽  
pp. 784-787 ◽  
Author(s):  
R A Gibson ◽  
L Lattanzio ◽  
H McGee
Keyword(s):  
Rapid Determination ◽  
Chromatographic Determination ◽  
Reversed Phase ◽  
Detector Response ◽  
High Pressure Liquid Chromatographic ◽  
Liquid Chromatographic Method ◽  
Wide Range ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract Metronidazole and its known metabolites in plasma can be rapidly separated by a "high-pressure" liquid-chromatographic method that can also be adapted for rapid determination of tinidazole. Samples deproteinized with trichloroacetic acid (50 g/L final concentration) undergo isocratic separation on a reversed-phase C18 column eluted with an 8/92 (by vol) mixture of acetonitrile/KH2PO4 (5 mmol/L, pH 3.0). The method is sensitive, reliably detecting as little as 25 micrograms of metronidazole and (or) its metabolites per milliliter of plasma. The detector response varied linearly with concentration for all compounds tested over a wide range (25-500 micrograms/L). Within-day and between-day variation was generally less than 2.5% for all concentrations of all compounds tested. Various other antibiotics tested did not interfere.

Liquid Chromatographic Determination of Thiamine in Rodent Feed by Postcolumn Derivatization and Fluorescence Detection

1995 ◽  
Vol 78 (2) ◽  
pp. 307-309 ◽  
Author(s):  
Theresa A Gehring ◽  
Willie M Cooper ◽  
Claude L Holder ◽  
Harold C Thompson
Keyword(s):  
Chromatographic Determination ◽  
Reversed Phase ◽  
Detector Response ◽  
Fluorescence Excitation ◽  
Liquid Chromatographic Method ◽  
Essential Nutrient ◽  
Liquid Chromatographic Determination ◽  
Phase Liquid ◽  
Liquid Chromatographic

Abstract A liquid chromatographic method was developed for determination of the essential nutrient thiamine (vitamin Bi) in rodent feed. Thiamine was extracted with hydrochloric acid, separated by reversed-phase liquid chromatography, derivatized postcolumn to thiochrome with potassium hydroxide and potassium ferricyanide, and detected by fluorescence. Excitation and emission wavelengths were 370 and 430 nm, respectively. Detector response was linear in the range of 2.58 to 15.5 ng of thiamine injected. Instrument detection limit was 5 pg of thiamine injected.

Liquid Chromatographic Determination of Benzoyl Peroxide in Acne Preparations

1984 ◽  
Vol 67 (5) ◽  
pp. 913-915
Author(s):  
Chih-Kuang Chou ◽  
David C Locke
Keyword(s):  
Benzoyl Peroxide ◽  
Limit Of Detection ◽  
Chromatographic Determination ◽  
Detector Response ◽  
Electrochemical Detector ◽  
Reverse Phase ◽  
Order Of Magnitude ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract A rapid, precise, and accurate liquid chromatographic (LC) method is described for the determination of benzoyl peroxide (BP) in acne preparations. BP is extracted from a water dispersion of the preparation with dichloromethane (DCM), and an aliquot is eluted from a C-18 reverse phase LC column with acetonitrile-O.lOM aqueous NaCI04. Selective and sensitive quantitation is accomplished with a reductive mode electrochemical detector. This detector is an order of magnitude more sensitive than a 240 nm UV absorption detector; the lower limit of detection is 2 ng for a 4 μL injection. The recovery of BP is 99.4% and the detector response is linear to at least 2 μg per 4 μL injection.

Liquid Chromatographic Determination of Norflurazon and Its Initial Metabolite in Soil

1994 ◽  
Vol 77 (3) ◽  
pp. 752-755 ◽  
Author(s):  
William T Willian ◽  
Thomas C Mueller
Keyword(s):  
Limit Of Detection ◽  
Chromatographic Determination ◽  
Soil Samples ◽  
Detector Response ◽  
Liquid Chromatographic Separation ◽  
Relative Standard ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic ◽  
Soluble Components

Abstract A rapid, sensitive method for the determination of norflurazon in 4 soils is described. Data on the initial soil metabolite is also obtained in soils with low organic matter. The method consists of extraction of soil samples with methanol, filtration, liquid chromatographic separation of methanol-soluble components by using a C18 column, and fluorescence detection with excitation at 294 nm and emission measured at 398 nm. Recoveries from fortified soils were >90% for norflurazon and >80% for desmethylnorflurazon from the Shipps, Lexington, and Harkey soils. Average percent relative standard deviations over the soils examined was 5.5% for norflurazon and 8.7% for desmethylnorflurazon. The limit of detection for norflurazon was 10 ng/g soil, whereas the limit of detection for desmethylnorflurazon was 100 ng/g soil because of its smaller relative detector response.

Mass Spectrometric Identification and Gas-Liquid Chromatographic Determination of 2-Chloroethyl Esters of Fatty Acids in Spices and Foods

1979 ◽  
Vol 62 (4) ◽  
pp. 786-791
Author(s):  
David L Heikes ◽  
Kenneth R Griffitt
Keyword(s):  
Fatty Acids ◽  
Fatty Acid Content ◽  
Chromatographic Determination ◽  
Food Samples ◽  
Esterification Reaction ◽  
Gas Liquid Chromatography ◽  
Mass Spectrometric Identification ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract The 2-chloroethyl esters of 5 fatty acids have been identified in spice and food samples by gas-liquid chromatography-mass spectrometry (GLC/MS). Twenty-four spice samples were analyzed for the 2-chloroethyl esters of fatty acids by AOAC official multiple residue pesticide procedures using CLC with microcoulometric detection. The esters of capric, lauric, myristic, palmitic, and linoleic acids have been identified at levels up to 1400 ppm. 2-Chloroethyl linoleate was the most abundant ester in all samples. Several foods analyzed by the same procedures showed levels of 2-chloroethyl linoleate as high as 35 ppm. Recoveries from fortified samples ranged from 84 to 98% for the various esters. A method using an acid-catalyzed esterification reaction was developed to rapidly determine the fatty acid content of these spices. CLC analysis with microcoulometric detection was used. Recoveries from fortified samples ranged from 92 to 110%. After 2 spice samples found to be free of 2-chloroethyl esters were fumigated with ethylene oxide, the level of 2-chloroethyl linoleate reached 77 ppm. All levels of 2-chloroethyl esters were confirmed by GLC/MS.

Liquid Chromatographic Determination of Propranolol Hydrochloride in Various Dosage Forms

1988 ◽  
Vol 71 (4) ◽  
pp. 761-763
Author(s):  
Carolyn S Olsen ◽  
Henry S Scroggins
Keyword(s):  
Pharmaceutical Preparations ◽  
Chromatographic Determination ◽  
Dosage Forms ◽  
Detector Response ◽  
Propranolol Hydrochloride ◽  
Reverse Phase ◽  
Liquid Chromatographic Method ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract A simple and rapid liquid chromatographic method is described for the determination of propranolol hydrochloride in pharmaceutical preparations. The separation was achieved on a reverse-phase octylsilane (C8) column by using a mobile phase composed of a mixture of 0.5 g dodecyl sodium sulfate in 18 mL (0.15 M) H3P04 plus 90 mL methanol, 90 mL acetonitrile, and 52 mL water. Detector response was linear for 0.03-3.1 mg/mL of propranolol. Recoveries from synthetic mixtures ranged from 99.6 to 101.7%. The results obtained by the proposed method were similar to those obtained by the USP XXI method.

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