Evaluation of Gas-Liquid Chromatography in Assays for Blood Volatiles

1965 ◽  
Vol 11 (11) ◽  
pp. 1023-1035 ◽  
Author(s):  
Alan Mather ◽  
Angel Assimos
Keyword(s):  
Liquid Chromatography ◽  
Alcohol Concentration ◽  
Quantitative Assay ◽  
Gas Liquid Chromatography ◽  
Internal Reference ◽  
Detection And Identification ◽  
Large Populations ◽  
The Common ◽  
Low Levels ◽  
Better Than

Abstract A simple screening by gas-liquid chromatography (GLC) can provide definitive answers in the detection and identification of a number of volatile substances, including acetone and the common alcohols. After identification, quantitative assay by an internal-reference technic yields highly specific values for ethyl alcohol concentration with a precision at least equal to (and for low levels, better than) that of conventional assays. The unique advantage of GLC is in its simultaneous quantitative assay of mixtures, some of which cannot be satisfactorily assayed or even recognized in any other way. The combination of speed and negligible sample volumes render the technic valuable for sequential studies on capillary blood samples and, potentially, for mass screening of large populations.

A quantitative assay for vanillylmandelic acid (VMA) by gas-liquid chromatography

1965 ◽  
Vol 13 (3) ◽  
pp. 544-551 ◽  
Author(s):  
Sherwin Wilk ◽  
Stanley E. Gitlow ◽  
Milton Mendlowitz ◽  
Morton J. Franklin ◽  
Herman E. Carr ◽  
...  
Keyword(s):  
Liquid Chromatography ◽  
Quantitative Assay ◽  
Gas Liquid Chromatography ◽  
Vanillylmandelic Acid

Thin Layer and Gas-Liquid Chromatography of Cholesterol in Fats and Oils. I. Development of Method

1969 ◽  
Vol 52 (4) ◽  
pp. 774-778
Author(s):  
C W Thorpe ◽  
Linda Pohland ◽  
D Firestone
Keyword(s):  
Liquid Chromatography ◽  
Thin Layer ◽  
Thin Layer Chromatography ◽  
Unsaponifiable Matter ◽  
Fats And Oils ◽  
Cholesterol Content ◽  
Gas Liquid Chromatography ◽  
Animal Fat ◽  
Low Levels ◽  
Layer Chromatography

Abstract A inethod is described for analysis of sterols by thin layer chromatography-gas liquid chromatography (TLC-GLC). Sterols are isolated from other components of unsaponifiable matter by preparative TLC. The sterols are quantitatively removed from the TLC plate, extracted from the silica gel, and analyzed by GLC. This method has been used to detect low levels (2–3%) of animal fat in vegetable oil by measuring the cholesterol content of the animal fatvegetable oil admixtures.

Detection and quantification of non-milk fat in mixtures of milk and non-milk fats

1980 ◽  
Vol 47 (3) ◽  
pp. 295-303 ◽  
Author(s):  
Ralph E. Timms
Keyword(s):  
Liquid Chromatography ◽  
Vegetable Oil ◽  
Milk Fat ◽  
Triglyceride Composition ◽  
Gas Liquid Chromatography ◽  
Confidence Limits ◽  
Pure Milk ◽  
Image Position ◽  
Detection And Quantification ◽  
Better Than

SUMMARYThe triglyceride compositions of 76 Australian milk fats obtained from 3 factories during a whole year were determined by gas-liquid chromatography. It was shown that all the data fitted the equationwith a S.D. of of 0·7088 where C40, C42 and C44 are the weight percentages of triglycerides with carbon numbers 40, 42 and 44. The triglyceride compositions of 10 samples of milk fat from countries other than Australia were also shown to fit the equation. If the equation is assumed to define pure milk fat, it is shown that as little as 5% of any non-milk fats can be detected with > 99% confidence. The amount of non-milk fat in mixtures of milk and non-milk fats can be quantified to better than ±2% with > 95% confidence. Also, the identity of the non-milk fat can usually be deduced by calculation of its triglyceride composition. Analyses of known mixtures and of chocolate and a table spread comprising butter and vegetable oil showed an agreement between observed and expected results well within the predicted confidence limits.

Amphetamines in Human Urine: Rapid Estimation by Gas—Liquid Chromatography

1970 ◽  
Vol 16 (9) ◽  
pp. 786-788 ◽  
Author(s):  
J W Schweitzer ◽  
A J Friedhoff
Keyword(s):  
Liquid Chromatography ◽  
Human Urine ◽  
Excretion Rate ◽  
Low Ph ◽  
Gas Liquid Chromatography ◽  
Reference Compound ◽  
Internal Reference ◽  
Rapid Estimation ◽  
Amphetamine Psychosis

Abstract A procedure is described for the quantitative determination of amphetamine and p-methoxyamphetamine and for the semiquantitative determination of methamphetamine, mephentermine, and normephentermine in human urine. An internal reference compound, phenethylamine, is added to 5 ml of urine. The urine is extracted at low pH to remove acidic contaminants, then at high pH with chloroform, in which the amines were acetylated with acetic anhydride. After evaporation, the residue, dissolved in dioxane, is injected onto a column at 215°C, packed with 8% ethyleneglycol adipate on Chromosorb W, 100-120 mesh, except at both ends, where the packing was 8% silicon rubber SE 30 on Chromosorb W, 100-120 mesh. The excretion rate of amphetamines by patients admitted with a diagnosis of amphetamine psychosis was measured.

A METHOD FOR THE GROUP ANALYSIS OF STEROIDS IN MILK

1973 ◽  
Vol 72 (2) ◽  
pp. 391-400 ◽  
Author(s):  
J. A. B. Darling ◽  
R. A. Harkness
Keyword(s):  
Liquid Chromatography ◽  
Group Analysis ◽  
Gas Liquid Chromatography ◽  
Present Survey ◽  
Systematic Analysis ◽  
Milk Samples ◽  
Low Levels ◽  
Almost All ◽  
Mechanical Extraction ◽  
Layer Chromatography

ABSTRACT A method has been developed for the systematic analysis of groups of steroids in milk. The procedure consists of saponification, gentle mechanical extraction, oxidation with CrO3, and a Girard separation, followed by thin-layer chromatography of the ketonic fraction. Final separation and estimation is by gas liquid chromatography. The reliability criteria of the method have been examined. A 5α steroid, 5α-androstane-3,17-dione, was obtained from almost all milk samples in amounts equivalent to a concentration of 0.54 μg/100 ml of cows' milk. The present survey has shown that other steroids can sometimes be found in human and cows' milk but only at low levels. The procedure can help in the isolation and definite identification of those steroids which are detectable.

A Screening Method for Determining Nitrofuran Drug Residues in Animal Tissues

1975 ◽  
Vol 58 (6) ◽  
pp. 1227-1231 ◽  
Author(s):  
John J Ryan ◽  
Young C Lee ◽  
Jo A Dupont ◽  
Claudette F Charbonneau
Keyword(s):  
Liquid Chromatography ◽  
Screening Method ◽  
Hydrolysis Product ◽  
Electron Capture Detection ◽  
Gas Liquid Chromatography ◽  
Organic Residue ◽  
Animal Tissues ◽  
Aqueous Acid ◽  
Muscle Tissues ◽  
Low Levels

Abstract A method was developed for measuring low levels of total nitrofurans in animal tissues and milk. The antimicrobial nitrofurans (5 or more products) used in agriculture are extracted from tissue with aqueous acid in the presence of ethyl acetate. After centrifugation and evaporation, the organic residue is washed with hexane and the nitrofurans are hydrolyzed to 5-nitrofuraldehyde in aqueous acid at 70°C. The hydrolysis product is extracted with benzene and measured by gas-liquid chromatography with electron capture detection. Recoveries of nitrofurazone and furazolidone from fortified poultry and swine tissues at the levels of 0.5 and 0.1 ppm are 75 and 65%, respectively. This procedure can be used to detect the total nitrofuran content of as little as 10 ppb muscle tissues and milk, 100 ppb liver, and 50 ppb fat with no interference from related veterinary nitrodrugs.

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