Gas Chromatographic Method For Determination Research Articles

Gas Chromatographic Methods for Determination of γ-BHC in Technical Emulsifiable Concentrates and Water-Dispersible Powder Formulations and in Lindane Shampoo and Lotion: Collaborative Study

Although the gas chromatographic separation of the isomers of BHC was demonstrated two decades ago, the present AOAC method of analysis of BHC for gamma-isomer (lindane) content is based on a separation carried out on a liquid chromatographic partition column. A method of analysis has been developed that uses an OV-210 column for separation of the gamma-isomer from the other isomers and impurities in technical BHC. Di-n-propyl phthalate was chosen as an internal standard. The same system allows quantitation of lindane in lotion and shampoo after these products are extracted with ethyl acetate-isooctane (1 + 4). The analytical methods were subjected to a collaborative trial with 10 laboratories. The coefficient of variation for technical BHC was 2.83%. For the water-dispersible powder and emulsifiable concentrate, the coefficients of variation were 2.89% and 4.62%, respectively. Coefficients of variation for 1% lindane lotion and shampoo were 4.36% and 11.92%, respectively. The method has been adopted official first action.

Malt Beverages and Brewing Materials: Gas Chromatographic Determination of Ethanol in Beer

Abstract The American Society of Brewing Chemists collaboratively tested a gas chromatographic method for determination of ethanol in beer. Ten laboratories collaborated in a comparison of the ASBC reference method for alcohol by distillation with the GC method. The latter was shown to be at least as precise as the former, it is more rapid, and it can be used for in-line or process monitoring. The method has been adopted official first action.

Capillary gas chromatographic method for determination of flumecinol in plasma and saliva

Capillary gas chromatographic method for determination of flumecinol in plasma and saliva

Gas chromatographic method for determination of carbon monoxide in atmospheric air

This article describes a test method being used to monitor the purity of air in populated areas and the atmosphere at the Fergana Petroleum Refinery. It presents an improved procedure for determination of CO content with concentration of CO on silver-containing type NaY zeolite and subsequent detection in the katharometer of an LKhM-8 MD chromatograph. It points out that current chromatographic methods for the determination of the CO content in atmospheric air are complex and laborious, and they involve the use of a reactor to convert the CO to methane, or liquid nitrogen to cool the trap.

An electron capture gas chromatographic method for determination of residues of 1,2-dibromoethane in fumigated grapefruit.

An electron capture gas chromatographic method for determination of residues of 1,2-dibromoethane in fumigated grapefruit.

A new gas chromatographic method for determination of amino acid levels in human serum

Amino acid levels of biological fluids are usually determined by the classical ion exchange procedure. Although the gas Chromatographie method offers the advantage of higher sensitivity and speed of analysis, apparent difficulties in achieving accuracy and precision similar to the ion exchange procedure prevented its acceptance as a routine method. The main problems associated with gas Chromatographie amino acid analysis were overcome by application of a novel approach called enantiomer-labelling: the optical antipode to each L-amino acid is added to the sample prior to the clean-up and serves as an internal standard having identical chemical properties. The enantiomers of all amino acids are separated by gas chromatography on capillaries coated with a thermally stable, chiral stationary phase. The shortcomings previously inherent in the gas Chromatographie method are thus eliminated. Accuracy and precision of the new procedure are equal or better than of the classical ion exchange method.

Simplified method for determination of the tetracyclic antidepressant mianserin in human plasma using gas chromatography with nitrogen detection

A simplified gas chromatographic method for determination of the antidepressant drug mianserin in human plasma is described. Application of a nitrogen-sensitive detector reduces the assay procedure to extraction, concentration and gas chromatographic determination. The method is suitable to determine mianserin in human plasma at the 1 ng/ml level on a routine basis. At the 20 ng/ml level the deviation of the mean from the true value and the relative standard deviation amount to 1.0% and 6.8%, respectively.

Determination of trihalomethanes (THM) in water using high efficiency solvent extraction

Abstract A rapid solvent extraction method for gas chromatographic determination of trihalomethanes in water has been developed. The analytical results were shown to be dependent on storage time of water samples and different preservation techniques were investigated. The method has been applied to different types of water samples including drinking water and industrial waste water. Among 107 drinking water samples investigated, 90% contained 0.2–25 μ g 1 −1 trihalomethanes.

IUPAC Gas Chromatographic Method for Determination of Fatty Acid Composition: Collaborative Study

An international collaborative study of IUPAC methods II.D.19 and II.D.25 for preparation and GLC analysis of fatty acid methyl esters was begun in 1976. The IUPAC methodology, applicable to animal and vegetable oils and fats and fatty acids from all sources, contains special instructions for preparation and analysis of methyl esters of fatty acids containing 4 or more carbon atoms (analysis of milk fat). Twenty-three collaborators participated in the analysis of 5 known mixtures, 4 vegetable oils, 1 fish oil, and 2 butterfats. Several blind duplicate samples were included. The experimental data were subjected to statistical analysis to examine intra- and interlaboratory variation. Reproducibility and accuracy data for the higher fatty acid (14:0-22:1) mixtures and fish and vegetable oils were satisfactory and were in good agreement with results from an AOCS Smalley Committee check sample program involving analysis of the same samples. Typical coefficients of variation (%) at various concentrations were 15 (2% level), 8.5 (5% level), 7 (10% level), and 3 (50% level). Low recoveries and poor reproducibility were characteristics of results obtained for butyric acid in the butterfat and related known mixtures. A coefficient of variation of about 19% was found for analysis of butyric acid in butterfat, vs coefficients of variation in the range of 4-13% for similar levels of other components in butterfat and other samples. The IUPAC methodology for GLC analysis of fats and oils other than milk fats has been adopted by the AOAC as official first action to replace the current GLC method, 28.063-28.067.

Precision of an automated all‐glass capillary gas chromatography system with an electron capture detector for the trace analysis of estrogens

AbstractSubnanogram detection of steroids has become increasingly important today. One applicable method for gas chromatographic determination of subnanogram quantities of estrogens as halogenated derivatives is electron capture detection. HFB‐derivatives of 7 different estrogens were automatically injected onto a prolonged narrow bore wall‐coated glass capillary column. Normal split injection could not be used for this trace analysis because of too much loss of sample. Only small amounts of sample were available from which double analysis had to be performed.Cross‐contamination of the automatic sampling system as well as precision of retention times and peak areas were determined.The type of injection described showed better quantitative results compared to the splitless injection technique.All details of the system used together with the results are this discussed in this paper.

Determination of volatile fatty acids in urine by gas chromatography on a new stationary phase

A rapid gas chromatographic method for determination of volatile fatty acids in urine is described. Acids up to five carbon atoms, including their isomers can be separated in less than six minutes on the new stationary phase Fluorad FC430. Good separation and sensitivity is obtained with isothermal conditions.

A gas chromatographic method for determination of acetate levels in body fluids

A simple, sensitive and accurate gas Chromatographie method for the determination of acetate in plasma and urine is described. Following precipitation of proteins by perchloric acid and removal of potassium perchlorate by precipitation with KOH, acetic acid is quantitated by injection of the acidified sample on a highly polar column. A flame ionization detector is used. Propionic acid is added to the sample initially as internal standard. The sample volume required for the analysis is 0.5 ml. The standard curve is linear in the range from 0.01 to 10 mmol/l. Recovery of added acetate is complete, and the coefficient of variation is less than 4% even at low concentrations. The concentration of free acetate in plasma from 10, and urine from 4, healthy humans ranged from 0.04 to 0.07 and 0.09 to 0.24 mmol/l, respectively.

Mass fragmentographic determination of docosenoic acid in rapeseed oils.

A highly sensitive and accurate reference method for determination of docosenoic acid (mainly erucic acid, 22:1n-9) in different rapeseed oils is described. A fixed amount of [1-14C] erucic acid methyl ester (about 1 microgram) is added to a fixed amount of oil. After treatment with sodium methoxide/methanol reagent and extraction with hexane, the amount of unlabeled erucic acid is determined from the ratio between the recordings at m/e 320 and m/e 322 obtained after analysis with a combined gas chromatograph-mass spectrometer equipped with an MID (multiple ion detector). The two ions used correspond to the M-32 peak in the mass spectrum of unlabeled and [1-14C] labeled erucic acid methyl ester. The relative standard deviation of the method is about 1.8%. The method was compared with a gas chromatographic method for determination of erucic acid.

An improved method for gas chromatographic determination of urinary xylitol and glucuronic, glucaric gulonic and ascorbic acids, with their values in the rat, rabbit, guinea-pig and marmoset.

1. Urinary levels of xylitol and glucuronic, glucaric, gulonic and ascorbic acids were measured in the rat, rabbit, guinea-pig and marmoset by an improved g.l.c. technique. 2. Administration of a compound (2-methylbenzanilide) known to be conjugated and excreted as a beta-glucuronide had some effect on the output of these compounds of the glucuronic acid pathway in all four species, and caused a significant decrease in gulonic acid in the rat.

Pharmacokinetic studies of Prethcamide in rats

A simple and sensitive gas chromatographic method for determination of Prethcamide components (I and II) in whole blood and tissues of rats has been developed. The method was used to study disposition of Prethcamide after oral and intravenous administration (60 mg/kg) to rats. Half-lives were found to be low for both constituent of Prethcamide, reaching 7.3 min and 6.5 min for I and II compounds respectively in the blood. They were longest in both cases in the kidney (9.4 min and 8.3 min).

A simple method for gas chromatographic determination of lidocaine in tissues.

A simple gas chromatographic method for the determination of lidocaine in tissues is described. Lidocaine is extracted from the tissue samples using liquid nitrogen. The recoveries of lidocaine from brain, liver, and muscle were 98.6, 99.8 and 89.1%, respectively. Results were reproducible to within 1.0% of lidocaine administered.

Rapid, sensitive gas-liquid chromatographic method for determination of amitriptyline and nortriptyline in plasma using a nitrogen-sensitive detector

A simple gas chromatographic method for determination of amitriptyline and nortriptyline in plasma using a nitrogen-sensitive detector is described. Concentrations of both drugs as low as 10 ng per ml plasma were measured. The precision and accuracy of the method are within acceptable limits.

Gas chromatographic method for determination of content of petroleum sulfones in wastewaters

Gas chromatographic method for determination of content of petroleum sulfones in wastewaters

Gas-Liquid Chromatographic Determination of Saccharin in Foods as a N-Methyl Derivative

A new methylation method for gas chromatographic determination of saccharin in foods was established. Saccharin was extracted from samples with ethyl acetate and converted to N-methylsaccharin by reaction with dimethyl sulfate in acetone at room temperature for 10 min. After decomposition of dimethyl sulfate with sodium hydroxide, N-methylsaccharin in the solution was determined by FID-gaschromatography using a column of SE-30 on Chromosorb W. Methyl palmitate was used as an internal standard. Rate of methylsaccharin formation from saccharin was 90.6-96.6%. This gas chromatographic method gave good results when applied to the determination of saccharin in several kinds of food and the recovery of saccharin added to food at the levels of 150 and 240 ppm was 77.3-94.3%.

Simple method for gas chromatographic determination of ethylene emitted from plant tissues

Simple method for gas chromatographic determination of ethylene emitted from plant tissues