Liquid Chromatographic Method for Quantitative Determination of Free Fatty Acids in Butter

1984 ◽  
Vol 67 (4) ◽  
pp. 718-721 ◽  
Author(s):  
Alan W Reed ◽  
Hilton C Deeth ◽  
Donald E Clegg
Keyword(s):  
Fatty Acids ◽  
Free Fatty Acids ◽  
Chromatographic Method ◽  
Water System ◽  
Internal Standard ◽  
Detection Range ◽  
Water Solvent ◽  
Liquid Chromatographic Method ◽  
Liquid Chromatographic

Abstract A liquid chromatographic method has been developed for the determination of free fatty acids in butter. The fatty acids are converted to the p-bromophenacyl esters, via a crown ether-catalyzed reaction, without separation from the other butter components. The esters are separated on a Cis-bonded silica column by using an acetonitrile-water solvent gradient and quantitated using the ester of heptadecanoic acid as internal standard. Cu, and C ,S:i co-elute in the acetonitrile-water system but are separated using an isocratic methanol-acetonitrile-water system. Limits of detection range from 7 ng for butyric acid to 45 ng for linoleic acid. The average coefficient of variation (n = 10) for 10 free fatty acids from,a butter was 5.83%.

A sensitive liquid-chromatographic method for determination of 3'-azido-3'-deoxythymidine (AZT) in plasma and urine.

1988 ◽  
Vol 34 (8) ◽  
pp. 1565-1568 ◽  
Author(s):  
M A Hedaya ◽  
R J Sawchuk
Keyword(s):  
Human Plasma ◽  
Prescription Drugs ◽  
Chromatographic Method ◽  
Internal Standard ◽  
Infectious Complications ◽  
Over The Counter ◽  
Internal Standards ◽  
Liquid Chromatographic Method ◽  
Liquid Chromatographic

Abstract We describe a liquid-chromatographic assay for AZT in human plasma and urine. This assay involves the use of two internal standards, allowing reference of AZT peaks to the appropriate internal standard, the choice depending on the range of concentrations encountered. This method is isocratic, specific, sensitive enough to allow quantification of AZT in concentrations observed clinically, and requires only 13 min of chromatographic time. We saw no interference from various over-the-counter and prescription drugs often used in treating the infectious complications of AIDS.

Gas-Liquid Chromatographic Determination of T-2 Toxin in Plasma

1983 ◽  
Vol 66 (4) ◽  
pp. 909-912 ◽  
Author(s):  
Steven P Swanson ◽  
Venkatachalam Ramaswamy ◽  
Val R Beasley ◽  
William B Buck ◽  
Harold H Burmeister
Keyword(s):  
Chromatographic Method ◽  
Limit Of Detection ◽  
Internal Standard ◽  
Aqueous Sodium Hydroxide ◽  
Chromatographic Determination ◽  
Florisil Column ◽  
Liquid Chromatographic Method ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract The gas-liquid chromatographic method for the determination of T-2 toxin in plasma is described. The toxin is extracted with benzene, washed with aqueous sodium hydroxide, and chromatographed on a small Florisil column; the heptafluorobutyryl derivative is prepared by reaction with heptafluorobutyrylimidazole. The T-2 HFB derivative is chromatographed onOV-1 at 230°C and measured with an electron capture detector. Iso-T-2, an isomer of T-2 toxin, is added to samples as an internal standard before extraction. Recoveries averaged 98.0 ± 5.5% at levels ranging from 50 to 1000 ng/m L. The limit of detection is 25 ng/mL.

Gas-chromatographic determination of mephenytoin and desmethylmephenytoin, after off-column alkylation.

1979 ◽  
Vol 25 (1) ◽  
pp. 172-175
Author(s):  
V A Raisys ◽  
A M Zebelman ◽  
S F MacMillan
Keyword(s):  
Active Metabolite ◽  
Chromatographic Method ◽  
Seizure Control ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Peak Height ◽  
Therapeutic Concentration ◽  
Liquid Chromatographic Method ◽  
Liquid Chromatographic

Abstract We describe a gas-liquid chromatographic method for determining mephenytoin and its active metabolite, desmethylmephenytoin, in human serum. 5-Methyl-5-phenylhydantoin is used as the internal standard. The method involves extraction of the drugs by adsorption onto charcoal and off-column derivatization to their pentyl derivatives. Peak height and concentration are linearly related and the day-to-day CV for therapeutic concentration is about 2 to 6%. No interferences by endogenous compounds or drugs commonly used for seizure control have been encountered.

Liquid Chromatographic Method for Determination of Cyfluthrin in Technical and Formulated Products

1990 ◽  
Vol 73 (4) ◽  
pp. 595-598
Author(s):  
Stephen C Slahck
Keyword(s):  
Liquid Chromatography ◽  
Chromatographic Method ◽  
Internal Standard ◽  
Normal Phase ◽  
Liquid Chromatographic Method ◽  
Phase Liquid ◽  
Liquid Chromatographic

Abstract A liquid chromatographic method for determination of cyfluthrin (Baythrold®, Tempo®) diastereomers In technical and formulated products has been developed. Samples are dissolved in dloxane-hexane and analyzed by normal-phase liquid chromatography using acetophenone as an internal standard. The method Is applicable to technical Baythrold, Baythrold 2 EC, Tempo 20 WP, and granular formulations. The method separates all 4 diastereomers of cyfluthrin and all impurities in less than 19 mln.

Liquid Chromatographic Determination of Propoxur in Technical and Formulated Products: Collaborative Study

1984 ◽  
Vol 67 (3) ◽  
pp. 497-499
Author(s):  
Stephen C Slahck ◽  
◽  
J B Audino ◽  
O O Bennett ◽  
B D Folsom ◽  
...  
Keyword(s):  
Chromatographic Method ◽  
Collaborative Study ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Reverse Phase ◽  
Liquid Chromatographic Method ◽  
Wettable Powder ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract A liquid chromatographic method for the determination of propoxur in technical and formulated products has been subjected to a collaborative study with 8 participating collaborators. Formulations are extracted with acetonitrile and analyzed by reverse phase chromatography, with n-butyrophenone as an internal standard. Collaborators were furnished with samples of technical, 70% wettable powder, 1.5 emulsifiable, and 2% bait. Coefficient of variation values obtained on the 4 samples were 0.34, 0.68, 3.25, and 5.41%, respectively. The method has been adopted official first action.

Gas Chromatographic, Liquid Chromatographic, and Titrimetric Procedures for Determination of Glycerin in Allergenic Extracts and Diagnostic Antigens: Comparative Study

1987 ◽  
Vol 70 (5) ◽  
pp. 825-828
Author(s):  
Alfred V Del Grosso ◽  
Joan C May
Keyword(s):  
Chromatographic Method ◽  
Internal Standard ◽  
Sodium Metaperiodate ◽  
Oxidation Method ◽  
Allergenic Extracts ◽  
Liquid Chromatographic Method ◽  
Chromatographic Procedure ◽  
Gas Chromatographic Method ◽  
Liquid Chromatographic

Abstract Three methods for the determination of glycerin are examined as applied to several allergenic extracts and diagnostic antigens. The liquid chromatographic procedure uses a sulfonic acid functional PSDVB resin (Aminex HPX-87H), a mobile phase of 0.013N H2S04; and refractive index detection. The titrimetric procedure involves oxidation of glycerin with sodium metaperiodate followed by potentiometric titration of the resulting formic acid with sodium hydroxide. Samples are quantitated by comparing the equivalence point obtained from the sample to those obtained from a series of standards. The gas chromatographic procedure includes a column of 5% Carbowax 20 M on 80-100 mesh Chromosorb WHP; p-cresol was used as an internal standard. The 3 procedures are shown to be valid for the majority of product types examined. A positive interference was encountered in the titrimetric analysis of a tuberculin purified protein derivative that contained simple sugars. Recoveries of added glycerin ranged from 95.0 to 100.2% by the liquid chromatographic method, from 98.7 to 101.4% by the gas chromatographic method, and from 99.8 to 101.6% by the metaperiodate oxidation method when interference from simple sugars was not present. Coefficients of variation determined from 8 replicates of samples that contained glycerin were 2.2% or less for the liquid chromatographic method, 2.3% or less for the GC method, and 3.6% or less for the metaperiodate oxidation method.

Determination of acetaminophen and phenacetin in plasma by high-pressure liquid chromatography.

1977 ◽  
Vol 23 (6) ◽  
pp. 957-959 ◽  
Author(s):  
G R Gotelli ◽  
P M Kabra ◽  
L J Marton
Keyword(s):  
High Pressure ◽  
Liquid Chromatography ◽  
Chromatographic Method ◽  
Plasma Sample ◽  
Internal Standard ◽  
High Pressure Liquid Chromatographic ◽  
Liquid Chromatographic Method ◽  
Toxic Concentrations ◽  
Liquid Chromatographic

Abstract We describe a sensitive and precise high-pressure liquid chromatographic method in which acetoacetanilide is used as the internal standard to simultaneously determine acetaminophen and phenacetin in plasma. Therapeutic as well as toxic concentrations can be determined on as little as 0.1 ml of plasma. Sample preparation is rapid and chromatography is complete in 5 min. Quantitation is accurate at 0.5 mg/liter concentration for both drugs. Day-to-day precision within 5% is attainable. Of 36 other drugs tested, only theophylline interfered, with the determination of acetaminophen.

Collaborative Study of a Gas-Liquid Chromatographic Method for the Determination of Simazine

1976 ◽  
Vol 59 (4) ◽  
pp. 758-760
Author(s):  
Arthur H Hofberg ◽  
Lee C Heinrichs ◽  
Gene A Gentry
Keyword(s):  
Coefficient Of Variation ◽  
Chromatographic Method ◽  
Collaborative Study ◽  
Internal Standard ◽  
Matched Pair ◽  
Inert Material ◽  
Powder Formulation ◽  
Liquid Chromatographic Method ◽  
Liquid Chromatographic

Abstract A gas-liquid chromatographic method for the determination of simazine in a wettable powder formulation containing about 80% active ingredient was collaboratively studied, using a matched pair scheme. The samples were dissolved in dimethylformamide containing dioctyl phthalate as an internal standard, chromatographed on Carbowax 20M, and detected by using a flame ionization detector. Analysis of the 2 samples, based on peak height measurements, showed the following results: 1.5% overall coefficient of variation, 1.03% coefficient of variation for random error, and 0.23% systematic error. Sample A was an 80% powder formulation; Sample B was a 5% dilution of Sample A by the addition of inert material. The coefficients of variation were 1.20% for Sample A and 1.54% for Sample B. The larger variation in Sample B most likely resulted from nonuniform mixing during the dilution of Sample A. Since all collaborators used the same reference standard, the variation found in Sample A is more indicative of the variability of the method. The method has been adopted as official first action.

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