Determination of Docosenoic Acids in Fats and Oils by Gas-Liquid Chromatography

1974 ◽  
Vol 57 (5) ◽  
pp. 1161-1164
Author(s):  
Henry B S Conacher ◽  
Rajinder K Chadha
Keyword(s):  
Methyl Esters ◽  
Internal Standard ◽  
Fats And Oils ◽  
Glycol Succinate ◽  
Gas Liquid Chromatography ◽  
Internal Standard Peak ◽  
Peak Areas ◽  
Diethylene Glycol Succinate ◽  
Liquid Chromatographic

Abstract A rapid gas-liquid chromatographic (GLC) procedure has been developed for the determination of docosenoic acids in fats and oils. The method involves conversion of a known weight of oil to methyl esters using sodium methoxide-methanol, with a known weight of methyl tetracosanoate used as an internal standard. After acidification and extraction into hexane, esters are analyzed by GLC on a diethylene glycol succinate column. The percentage of docosenoic acids is calculated from the docosenoate and internal standard peak areas. The method is particularly suited to the determination of low levels (<5%) of docosenoic acids.

Gas-Liquid Chromatographic Determination of Pirimicarb in Formulations: Collaborative Study

1981 ◽  
Vol 64 (6) ◽  
pp. 1315-1318
Author(s):  
Peter D Bland ◽  
◽  
J Bagness ◽  
W Black ◽  
L Brown ◽  
...  
Keyword(s):  
Collaborative Study ◽  
Chloroform Solution ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Gas Liquid Chromatography ◽  
Technical Product ◽  
Flame Ionization ◽  
Peak Areas ◽  
Liquid Chromatographic

Abstract A method is described for the determination of pirimicarb (2-(dimethylamino)-5,6-dimethyl-4-pyrimidinyl dimethylcarbamate) in formulated products by gas-liquid chromatography (GLC). Samples are dissolved in a chloroform solution of an internal standard and injected into a gas chromatograph equipped with a flame ionization detector. Quantitative data are obtained by comparing peak areas of the compound and internal standard with those obtained by injecting a standard solution. Eleven collaborators made replicate determinations on 6 samples including a technical product, a granular product, and 4 powder products. The average coefficient of variation was 1.14% for the technical product, 1.82% for the granular product, and 0.73% for the powder products.

Gas-Liquid Chromatographic Identification and Determination of Alkanolamines. I. Application to Aerosol Hair Sprays

1971 ◽  
Vol 54 (5) ◽  
pp. 1175-1178
Author(s):  
Margaree H Champion ◽  
John H Jones
Keyword(s):  
Acetic Anhydride ◽  
Diethylene Glycol ◽  
Glycol Succinate ◽  
Diethylene Glycol Succinate ◽  
Liquid Chromatographic

Abstract Alkanolamines, in the absence of water, are converted to the amide ester or triacetate with acetic anhydride-pyridine mixture. The amide ester or triacetate of the alkanolamine is determined by GLC on a column containing diethylene glycol succinate on Chromosorb G. Procedures for determining alkanolamines in various hair sprays are described; recoveries by the proposed procedure were satisfactory. The method developed was applied to the following 4 alkanolamines: 2-amino-2-methyl-1-propanol, 2-amino-2-methyl-1,3-propanediol, 2-amino-2-ethyl-1,3-propanediol, and triisopropanolamine.

Gas-Liquid Chromatographic Determination of Pyridazinones in Technical Products and Formulations

1978 ◽  
Vol 61 (1) ◽  
pp. 161-163
Author(s):  
Giuseppe Cellerino ◽  
Mariarosa Re
Keyword(s):  
Internal Standard ◽  
Standard Technique ◽  
Chromatographic Determination ◽  
Gas Liquid Chromatography ◽  
Flame Ionization ◽  
Selective Detector ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic ◽  
Technical Products

Abstract Simultaneous determination of the active ingredient and of by-products in technical and formulated pyridazinones was rapidly performed by gas-liquid chromatography with complete resolution of all compounds. Quantitative determination by the internal standard technique is accurate and precise. The lower limit of detectability is 8 × 10–12 g/sec with a flame ionization detector and 1 × 10–12 g/sec with a nitrogen-phosphorus selective detector operating in the nitrogen mode.

Gas-Liquid Chromatographic Determination of Volatile Organic Acids as Benzyl Esters with Applications to Tuna, Shrimp, and Eggs

1978 ◽  
Vol 61 (4) ◽  
pp. 973-981
Author(s):  
Walter F Staruszkiewicz ◽  
Enrique Fernandez-Flores ◽  
John F Bond
Keyword(s):  
Processing System ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Gas Liquid Chromatography ◽  
Rapid Preparation ◽  
Canned Tuna ◽  
Liquid Phases ◽  
Benzyl Esters ◽  
Liquid Chromatographic

Abstract Volatile acids are recognized as useful indicators of decomposition in a variety of foods. A method has been developed for the rapid preparation of benzyl esters of formic, acetic, propionic, isobutyric, and butyric acids and for their quantitative determination by gas-liquid chromatography. Esters were formed by reaction with BCl3-benzyl alcohol, followed by washing with aqueous ammonia before storage. They were chromatographed, using tetradecane as an internal standard, and were separated at 140°C on columns having DC-200 and SP-1000 as liquid phases. The method offers significant advantages, especially for the determination of formic acid, over the present official AOAC method, 17.042-17.046. Recoveries of volatile acids added to steam distillates of tuna extracts were ≥ 91% with mean recoveries for the 5 volatile acids of 96—104%. Applications to the analysis of canned tuna, frozen headless shrimp, and frozen whole egg resulted in recoveries of ≥ 8 2% with mean recoveries for the 5 acids of 91—101%. The method was compatible with an automated gas chromatograph-data processing system.

Gas-Liquid Chromatographic Determination of TYans-Unsaturation in Fats and Oils on Packed Columns: Effect of Positional Isomers

1978 ◽  
Vol 61 (3) ◽  
pp. 702-708
Author(s):  
Henry B S Conacher ◽  
Jagannath R Iyengar
Keyword(s):  
Fats And Oils ◽  
Chromatographic Determination ◽  
Packed Columns ◽  
Gas Liquid Chromatography ◽  
Positional Isomers ◽  
Tubular Columns ◽  
Acid Isomerization ◽  
Cis And Trans ◽  
Liquid Chromatographic

Abstract Studies in our laboratories indicated that the trans contents of a number of commercial margarines, determined by gas-liquid chromatography (GLC) on a 15 ft column packed with 10% Silar IOC, were approximately 80-85% of those determined by infrared spectroscopy. This is mainly due to overlap of some of the trans positional isomers with the cis positional isomers in the octadecenoate fraction, shown by studies involving determination of the transoctadecenoate content of the margarines by silver ion thin layer chromatography/GLC, and by preparation and study of the GLC behavior of the cis and trans positional isomers of Δ6-, Δ9-, Δ12-, and Δl5-octadecenoates. The last 3 isomers were prepared by hydrazine reduction and nitrous acid isomerization of linoleic and linolenic acids. Since it is possible that longer, more efficient columns might result in better separation of the cis- and traru-octadecenoate isomers, it is recommended that studies be continued on longer packed columns (20 ft) and possibly on support-coated open tubular columns.

Gas-Liquid Chromatographic Determination of β-Asarone in Wines and Flavors

1976 ◽  
Vol 59 (3) ◽  
pp. 675-677
Author(s):  
Randolph H Dyer ◽  
Glenn E Martin ◽  
Peter C Buscemi
Keyword(s):  
Liquid Chromatography ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Gas Liquid Chromatography ◽  
Ethyl Palmitate ◽  
Ultraviolet Spectra ◽  
Liquid Chromatographic Determination ◽  
Mass Spectrometery ◽  
Liquid Chromatographic

Abstract Wine samples containing β-asarone (cis-2,4,5-trimethoxy-1-propenylbenzene) are distilled; β-asarone is extracted by hexane and then quantitatively determined by gas-liquid chromatography (GLC), using ethyl palmitate as the internal standard. The GLC procedure is rapid and yields precise and accurate results. Mass spectrometery confirmed the identity of the GLC peak as β-asarone. The ultraviolet spectra of β-asarone and its isomer were also determined.

Gas-Liquid Chromatographic Determination of p-Chloroacetanilide in Acetaminophen

1978 ◽  
Vol 61 (1) ◽  
pp. 68-71
Author(s):  
Dorothy K Wyatt ◽  
Lee T Grady
Keyword(s):  
Liquid Chromatography ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Gas Liquid Chromatography ◽  
Flame Ionization ◽  
Glass Column ◽  
Retention Characteristics ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract Gas-liquid chromatography (GLC) coupled with column chromatography was used to accurately determine as little as 25 ppm p-chloroacetanilide in acetaminophen. p-Chloroacetanilide was eluted from a pH 8 phosphate-buffered diatomite partition column by using purified tetrachloroethylene (acetaminophen was retained). This solution was concentrated, internal standard (docosane) was added, and p-chloroacetanilide was determined by using a 0.9 m × 2 mm glass column packed with 3% Poly A 103 on Supelcoport and a flame ionization detector with electronic integration. Standard curves were linear for 10–100 ppm p-chloroacetanilide. Various chromatographic materials were investigated for optimal retention characteristics. High pressure liquid chromatography (HPLC) was also evaluated as an alternative; however, lack of reproducibility of the HPLC column favored the GLC procedure.

Gas-Liquid Chromatographic Determination of Diethylstilbestrol Monomethyl Ether in Diethylstilbestrol

1974 ◽  
Vol 57 (1) ◽  
pp. 79-81
Author(s):  
Frank E Gainer ◽  
William J Chiasson
Keyword(s):  
Sodium Hydroxide ◽  
Chloroform Solution ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Monomethyl Ether ◽  
Detector Response ◽  
Internal Standard Peak ◽  
Gas Chromatographic Method ◽  
Liquid Chromatographic

Abstract A gas chromatographic method is described for the determination of the monomethyl ether of diethylstilbestrol (MME) in diethylstilbestrol (DES). A 1 g sample of DES is dissolved in an aqueous solution of 0.5N sodium hydroxide and extracted with a chloroform solution containing benefin, the internal standard. The chloroform solution is back-extracted with sodium hydroxide, and an aliquot is chromatographed after silylation. The MME peaks (cis and trans') are measured relative to the internal standard peak. The method was tested for accuracy within the 120—2000 ppm range, and a linear plot of detector response vs. concentration was obtained. The method is also suitable for the determination of diethylstilbestrol dimethyl ether (DME) if present with MME in a DES sample.

DETERMINATION OF SOLVOLYSED SULPHATE ESTERS OF DEHYDROEPIANDROSTERONE AND ANDROSTERONE IN HUMAN PERIPHERAL PLASMA BY GAS-LIQUID CHROMATOGRAPHY

1968 ◽  
Vol 42 (4) ◽  
pp. 567-578 ◽  
Author(s):  
D. Y. WANG ◽  
R. D. BULBROOK ◽  
B. S. THOMAS ◽  
M. FRIEDMAN
Keyword(s):  
Internal Standard ◽  
Gas Liquid Chromatography ◽  
Dehydroepiandrosterone Sulphate ◽  
Adult Men ◽  
Peripheral Plasma ◽  
Liquid Chromatographic Method ◽  
The Mean ◽  
Liquid Chromatographic ◽  
Abrupt Rise

SUMMARY A gas—liquid chromatographic method is described for the routine determination as the chloromethyldimethylsilyl ethers of plasma dehydroepiandrosterone and androsterone obtained after solvolysis of a steroid sulphate fraction. 5α-Dihydrotestosterone sulphate is used as an internal standard. The levels of dehydroepiandrosterone sulphate and androsterone sulphate have been measured in 61 males and 66 females aged 20 days to 91 yr. The steroid levels show an abrupt rise at the age of about 7 yr. and reach a peak between the ages of 20 and 30 yr. Thereafter they fall with advancing age. The mean level of dehydroepiandrosterone sulphate is significantly higher in adult men than in women but the mean level of androsterone sulphate is similar.

Collaborative Study of Gas-Liquid Chromatographic Determination of Methaqualone in Pharmaceutical and Clandestine Preparations

1977 ◽  
Vol 60 (4) ◽  
pp. 935-939 ◽  
Author(s):  
Harold F Hanel
Keyword(s):  
Liquid Chromatography ◽  
Quantitative Determination ◽  
Collaborative Study ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Gas Liquid Chromatography ◽  
Coefficients Of Variation ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract Eight laboratories collaboratively studied a procedure for the quantitative determination of methaqualone. HCl in pharmaceutical and clandestine preparations. Methaqualone is extracted from an aqueous bicarbonate solution into chloroform and quantitated by gas-liquid chromatography on a 3% OV-1 column. Tetraphenylethylene is used as an internal standard. Two commercial preparations and 4 sample mixtures prepared by the author were studied. Recoveries for the 4 prepared samples ranged from 100.0 to 102.6%, and the coefficients of variation ranged from 1.58 to 4.15% for the 6 samples studied. The method has been adopted as official first action.

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