Rapid Screening Method for Simultaneous Determination of Organochlorine and Organophosphate Pesticide Residues in Wheat by Gas-Liquid Chromatography

1974 ◽  
Vol 57 (4) ◽  
pp. 924-929
Author(s):  
Iser Levi ◽  
Thomas W Nowicki
Keyword(s):  
Ball Milling ◽  
Screening Method ◽  
Soxhlet Extraction ◽  
Rapid Screening ◽  
Electron Capture Detection ◽  
Gas Liquid Chromatography ◽  
Photometric Detection ◽  
Gas Chromatographic Method ◽  
Ground Wheat

Abstract A previously reported gas chromatographic method for screening of organochlorine residues in wheat has been modified to permit rapid simultaneous screening for common organochlorine and organophosphate residues in wheat. Ground wheat is extracted by ball-milling with ethyl ether-hexane (3+97). The extract is divided into 2 equal portions. One half is used without cleanup for determination of organophosphates by flame photometric detection. The other half is cleaned up on Florisil prior to determination of organoehlorines by electron capture detection. The mean average recovery of 9 organoehlorines from wheat fortified at 0.50 ppm was 80%. Wheat analyzed immediately after treatment with 15 organophosphates showed an average mean recovery of 93%. After 8 weeks' storage, 9 of 15 organophosphates were recovered in excess of 60%, with an average mean recovery of 90% at the 1.00 ppm fortification level. The average mean recovery for 9 organophophates was 7% lower for extraction by ball-milling with ethyl etherhexane than for Soxhlet extraction with methanol- chloroform (10+90).

Levels of Brominated Vegetable Oils in Soft Drinks by X-Ray Fluorescence Spectrometry and Gas-Liquid Chromatography

1970 ◽  
Vol 53 (3) ◽  
pp. 571-575
Author(s):  
H B S Conacher ◽  
J C Meranger ◽  
J Leroux
Keyword(s):  
Vegetable Oils ◽  
Screening Method ◽  
Soft Drinks ◽  
Fluorescence Spectrometry ◽  
Rapid Screening ◽  
Gas Liquid Chromatography ◽  
X Ray ◽  
Wide Range ◽  
Rapid Screening Method

Abstract A rapid screening method using X-ray fluorescence spectrometry has been developed for the detection and semiquantitative estimation of brominated vegetable oils in soft drinks. This method and a quantitative GLC technique have been applied to the determination of the brominated oil content in a wide range of soft drinks. Of 46 drinks examined, 23 contained brominated vegetable oils at levels between 7 and 85 mg/10 fluid oz of drink.

Gas-Liquid Chromatographic Screening Method for Determination of Methyl Mercury in Tuna and Swordfish

1983 ◽  
Vol 66 (1) ◽  
pp. 128-129
Author(s):  
Theron James
Keyword(s):  
Methyl Mercury ◽  
Methylene Chloride ◽  
Screening Method ◽  
Fish Tissue ◽  
Rapid Screening ◽  
Gas Liquid Chromatography ◽  
Absorption Method ◽  
Rapid Screening Method ◽  
Liquid Chromatographic

Abstract A rapid screening method has been developed for determining methyl mercury in tuna and swordfish. Fish tissue is blended with acidic KBr solution to release methyl mercury, which is then extracted into methylene chloride. After cleanup by partitioning with cysteine, the methyl mercury is extracted into toluene and determined by gas-liquid chromatography. The proposed method compares favorably with the official AOAC atomic absorption method.

Rapid Screening Procedure for Pesticides and Polychlorinated Biphenyls in Fish: Collaborative Study

1983 ◽  
Vol 66 (4) ◽  
pp. 969-973 ◽  
Author(s):  
D Ronald Erney ◽  
◽  
R L Bong ◽  
W Bulmer ◽  
L B Hansen ◽  
...  
Keyword(s):  
Polychlorinated Biphenyls ◽  
Petroleum Ether ◽  
Collaborative Study ◽  
Rapid Screening ◽  
Electron Capture Detection ◽  
Gas Liquid Chromatography ◽  
Coefficients Of Variation ◽  
Fish Samples ◽  
Analytical Time

Abstract A simplified rapid method is presented to determine organochlorine pesticides and polychlorinated biphenyls in fish. Samples are mixed with sodium sulfate and blended with petroleum ether. A portion of the blend is placed on a miniaturized Florisil column and compounds are eluted with mixtures containing 6 and 15% ethyl ether in petroleum ether. Gas-liquid chromatography with electron capture detection comparable to the official methods (29.018) is used for determination of residues. Each of 7 collaborators reported results in duplicate for 10 samples containing one or more of the following compounds: p,p’-DDD,p,p’-DDE, p,p’-DDT, dieldrin, heptachlor epoxide, Aroclor 1254, and Aroclor 1260. Recoveries ranged from 79.3 to 100.7%. The coefficients of variation between laboratories ranged from 6.3 to 20.6%. This method allows up to 80% reduction in reagents and up to 50% reduction in analytical time, and requires less laboratory space than current official methods. The method has been adopted official first action.

A Comparative Study of Methods for the Determination of Moisture in Cheese

1967 ◽  
Vol 50 (3) ◽  
pp. 547-555
Author(s):  
Theron E Strange
Keyword(s):  
Screening Method ◽  
Amyl Alcohol ◽  
Rapid Screening ◽  
Official Method ◽  
Gas Liquid Chromatography ◽  
Distillation Method ◽  
Basic Reference ◽  
Aoac Method ◽  
Comparative Results

Abstract Eleven types of cheese were analyzed for moisture by the official AOAC method and by a method proposed by the International Dairy Federation (IDF). Some cheeses were also analyzed by the AOAC rapid screening method and by a proposed distillation method. The IDF method requires mixing 3 g cheese with about 20 g dried and weighed sand, then drying at 105°C for 4 hours. In the proposed distillation method, moisture is distilled from cheese (9—15 g) with xylene and n-amyl alcohol (2 + 1) into a Bidwell-Sterling type of receiver. Comparative results show that the official method is not applicable to cheeses with a relatively high content of volatile compounds, such as Bleu cheese; that the AOAC rapid method and the distillation method give results in about 12 hours that agree well with the official method for other types of cheese; and that the IDF method gives results about 0.2 % lower than those by the official method (actual difference). Preliminary studies on the Karl Fischer titration procedure and a gas-liquid chromatography procedure indicate that these procedures may be suitable as basic reference methods

Collaborative Study of the Extraction of Plant Sterols from Adulterated Butter Oil Using a Digitonin-impregnated Celite Column

1970 ◽  
Vol 53 (3) ◽  
pp. 535-538
Author(s):  
Denis E Lacroix
Keyword(s):  
Liquid Chromatography ◽  
Vegetable Oil ◽  
Coefficient Of Variation ◽  
Collaborative Study ◽  
Screening Method ◽  
Rapid Screening ◽  
Gas Liquid Chromatography ◽  
Butter Oil ◽  
Average Coefficient ◽  
Rapid Screening Method

Abstract A rapid screening method for the analysis of the phytosterol, β-sitosterol, in butter oil adulterated with vegetable oil has been studied collaboratively. The sterols are removed from the adulterated butter oil by passing the sample through a digitonin-impregnated Celite 545 column, eluting the sterols with dimethyl sulfoxide, and analyzing the eluate for β-sitosterol by gas-liquid chromatography using a 3% JXR column. The average coefficient of variation for those samples containing more than 4 mg β-sitosterol/100 g adulterated butter oil is 12.6%. Therefore, β-sitosterol can be used as an index to qualitatively detect vegetable oil adulteration of butter oil.

Extraction and Cleanup of Fish, Sediment, and Water for Determination of Triaryl Phosphates by Gas-Liquid Chromatography

1981 ◽  
Vol 64 (1) ◽  
pp. 79-84
Author(s):  
Derek C G Muir ◽  
Norbert P Grift ◽  
John Solomon
Keyword(s):  
Liquid Chromatography ◽  
Soxhlet Extraction ◽  
Gel Permeation Chromatography ◽  
Gas Liquid Chromatography ◽  
Fish Samples ◽  
Alumina Treatment ◽  
Diphenyl Phosphate ◽  
Nitrogen Phosphorus ◽  
Acetone Hexane

Abstract Several techniques were evaluated for extracting triphenyl phosphate (TPP), 14C-labeled TPP, cresyl diphenyl phosphate, and tricresyl phosphate isomers (o-TCP, m-TCP, and p-TCP) from fish and sediment samples. Extracts of fish samples were cleaned up by gel permeation chromatography/alumina column chromatography; sediment extracts received alumina treatment only. Compounds were determined by gas-liquid chromatography (GLC) with nitrogenphosphorus detection. Methanol/Polytron and hexane/ball mill extraction of fish samples fortified at 0.01, 0.1, and 1.0 μg/g levels gave overall recoveries of the 5 compounds of 89 and 97%, respectively. Methanol recovered more radioactivity (97%) from fish exposed to 14C-TPP in aquaria for 24 h than did hexane from fish exposed for 16 h (79%). Refluxing fortified sediment (0.05 and 0.5 μg/g) with methanol-water (9+1) gave significantly higher recoveries (88%) of the 5 triaryl phosphates than did dichloromethane-methanol (1+1) reflux or acetone-hexane (1+1) Soxhlet extraction. Recoveries of TPP and o-, m- and p-TCP from fortified river water (0.5, 5.0, and 50 μg/L) by shaking with dichloromethane ranged from 91 to 118%. Some problems were encountered with interfering GLC peaks at low (μg/g) levels in fish and sediment extracts despite the use of nitrogen-phosphorus specific detectors.

Gas-Liquid Chromatographic Determination of Total Inorganic Iodine in Milk

1977 ◽  
Vol 60 (6) ◽  
pp. 1307-1309 ◽  
Author(s):  
Hendrik J Bakker
Keyword(s):  
Liquid Chromatography ◽  
Iodine Content ◽  
Chromatographic Determination ◽  
Electron Capture Detection ◽  
Gas Liquid Chromatography ◽  
Relative Standard ◽  
Liquid Chromatographic Determination ◽  
Inorganic Iodine ◽  
Liquid Chromatographic

Abstract Total inorganic iodine in milk is determined by conversion to iodobutanone, which is quantitated by gas-liquid chromatography and electron capture detection. As little as 10 μg/L can be determined. The thyroid-active iodine content of milk can be determined rapidly with a relative standard deviation of 1.9%. Average recoveries for added iodide and iodine were 95.5 and 94.6%, respectively.

Determination of Diazepam (Valium) Concentrations in Serum by Gas—Liquid Chromatography

1970 ◽  
Vol 16 (3) ◽  
pp. 177-179 ◽  
Author(s):  
Lowell B Foster ◽  
Christopher S Frings
Keyword(s):  
Liquid Chromatography ◽  
Chromatographic Method ◽  
Gas Liquid Chromatography ◽  
Gas Chromatograph ◽  
Serum Samples ◽  
The Many ◽  
Gas Chromatographic Method

Abstract A simple, rapid, and precise gas chromatographic method for determination of serum diazepam concentrations is described. Two milliliters of serum is extracted with chloroform, and the extract is concentrated and injected into a gas chromatograph. Of the many drugs and serum samples tested, none interferes with the determination of diazepam.

Gas-Liquid Chromatography and Flame Photometric Detection of Phosphine in Wheat

1978 ◽  
Vol 61 (4) ◽  
pp. 829-836 ◽  
Author(s):  
Thomas W Nowicki
Keyword(s):  
Liquid Chromatography ◽  
Screening Method ◽  
Gas Liquid Chromatography ◽  
Gas Chromatograph ◽  
Aluminum Phosphide ◽  
Photometric Detection ◽  
Residual Aluminum ◽  
Flame Photometric Detection ◽  
Rubber Septa ◽  
Electronic Integrator

Abstract A screening method using gas-liquid chromatography with flame photometric detection has been developed for determining phosphine in wheat. Phosphine is measured as the sum of physically bound intact phosphine and that derived from residual aluminum phosphide. Wheat is extracted in a closed, partially evacuated glass system by refluxing with 10% sulfuric acid. Liberated gases are swept into a gas-collection flask fitted with rubber septa to permit gas sampling. Aliquots of collected gas are injected into a gas chromatograph. Phosphine is quantitated by peak area as determined by an electronic integrator. Recoveries varied with concentration: 67% was recovered at 0.10 ppm and 98% was recovered at 19 ppm. For concentrations less than 1.5 ppm, the coefficient of variation was 9.95%. Using flame photometric detection, phosphine concentrations as low as 0.04 ppm were easily determined in wheat.

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