Collaborative Study of Gas-Liquid Chromatographic Method for Determining Methyl Parathion

1977 ◽  
Vol 60 (3) ◽  
pp. 720-723 ◽  
Author(s):  
Edwin R Jackson
Keyword(s):  
Methyl Parathion ◽  
Collaborative Study ◽  
Internal Standard ◽  
Peak Height ◽  
Flame Ionization ◽  
Coefficients Of Variation ◽  
Liquid Chromatographic Method ◽  
Technical Material ◽  
Standard Solution ◽  
Liquid Chromatographic

Abstract Methyl parathion in technical material, 4 lb/gal. emulsifiable concentrate, and 25% wettable powder was chromatographed on a 1.5% SE-30 + 1.5% OV-210 column with p,p′-DDE as internal standard and flame ionization detection. Three matched sample pairs were analyzed by 15 collaborators using peak height measurements. Liquids were diluted to volume with p,p′-DDE internal standard solution; wettable powders were extracted with chloroform-acetone (9+1), solvent was removed, and extracts were dissolved in internal standard solution. The mean of the coefficients of variation for the 6 samples was 1.65%. The method has been adopted as official first action.

Collaborative Study of High Pressure Liquid Chromatographic Method for Determining Methyl Parathion

1977 ◽  
Vol 60 (3) ◽  
pp. 724-727
Author(s):  
Edwin R Jackson
Keyword(s):  
Methyl Parathion ◽  
Collaborative Study ◽  
Internal Standard ◽  
Peak Height ◽  
Emulsifiable Concentrate ◽  
Coefficients Of Variation ◽  
Liquid Chromatographic Method ◽  
Technical Material ◽  
Water Saturated ◽  
Liquid Chromatographic

Abstract Methyl parathion in technical material, 4 lb/gal. emulsifiable concentrate, and 6 lb toxaphene-3 lb methyl parathion/gal. emulsifiable concentrate was chromatographed on microparticulate silica with 40% water-saturated chloroform mobile phase and 254 nm ultraviolet detection. Ten collaborators reported results on 3 matched pairs of samples by peak height measurements with acetophenone as internal standard. The mean of the coefficients of variation for the 6 samples was 1.71%. Results for 4 of the samples were compared with gas-liquid chromatographic results on the same samples. No difference in the means by the 2 methods was noted at the 95% confidence level. The method has been adopted as official first action.

Gas-Liquid Chromatographic Method for the Analysis of Technical Dichlobenil and Its Formulations:1 Collaborative Study

1979 ◽  
Vol 62 (1) ◽  
pp. 8-10
Author(s):  
Pieter Van Bemmel ◽  
Bram Van Rossum ◽  
Albertus Martijn
Keyword(s):  
Chromatographic Method ◽  
Collaborative Study ◽  
Internal Standard ◽  
Flame Ionization ◽  
Coefficients Of Variation ◽  
Liquid Chromatographic Method ◽  
Technical Material ◽  
Aoac Method ◽  
Liquid Chromatographic ◽  
Technical Sample

Abstract A gas-liquid chromatographic method for determining dichlobenil in technical material and formulations was collaboratively studied by 7 laboratories. Five samples were chromatographed on a 10% Carbowax 20M column with methyl myristate as the internal standard and flame ionization detection. The estimates of the repeatability (different analysts) and the reproducibility, expressed as coefficients of variation, were, respectively, 0.8 and 1.0% for the technical sample, 1.4 and 1.7% for the wettable powder, and 3.5 and 4.6% for the granular formulations. This method was adopted as a full CIPAC-AOAC method.

Gas-Liquid Chromatographic Method for Analysis of Pentachloronitrobenzene Formulations: Collaborative Study

1982 ◽  
Vol 65 (1) ◽  
pp. 110-114
Author(s):  
Alan R Hanks
Keyword(s):  
Chromatographic Method ◽  
Collaborative Study ◽  
Internal Standard ◽  
Peak Height ◽  
Matched Pairs ◽  
Commercial Products ◽  
Coefficients Of Variation ◽  
Liquid Chromatographic Method ◽  
Wettable Powder ◽  
Liquid Chromatographic

Abstract A collaborative study has been conducted on a gasliquid chromatographic (GLC) method for determining pentachloronitrobenzene (PCNB) in formulations. Wettable powder, liquid, and granular matched pairs of commercial products were analyzed by 17 laboratories using peak height measurements and by 12 laboratories using integrator area measurements. Samples were dissolved in chloroform and aliquots were mixed with internal standard before GLC analysis on a 5% SE-30 column. Mean coefficients of variation for the completed study were 1.54% for integrator area measurements and 1.35% for peak height measurements. The method has been adopted official first action.

Collaborative Study of a Gas-Liquid Chromatographic Method for the Analysis of Chlorobenzilate and Chloropropylate

1975 ◽  
Vol 58 (3) ◽  
pp. 516-519
Author(s):  
Arthur H Hofberg ◽  
Lee C Heinrichs ◽  
Gene A Gentry
Keyword(s):  
Coefficient Of Variation ◽  
Chromatographic Method ◽  
Collaborative Study ◽  
Internal Standard ◽  
Peak Height ◽  
Matched Pair ◽  
Flame Ionization ◽  
Liquid Chromatographic Method ◽  
Liquid Chromatographic

Abstract A gas-liquid chromatographic method for the determination of chlorobenzilate and chloropropylate in liquid formulations containing about 46 and 26% active ingredient, respectively, was collaboratively studied, using a matched pair scheme. The samples were dissolved in acetone containing dibenzyl succinate as an internal standard and chromatographed on Carbowax 20M, using a flame ionization detector. Analyses of 4 samples by 13 collaborators using peak height measurements showed the following results: chlorobenzilate—2.5% overall coefficient of variation, 1.0% coefficient of variation for the random error; and 0.7% systematic error; chloropropylate—2.0, 1.4, and 0.4%, respectively. The method has been adopted as official first action.

Collaborative Study of a Gas-Liquid Chromatographic Method for the Analysis of Propazine

1975 ◽  
Vol 58 (3) ◽  
pp. 513-515
Author(s):  
Arthur H Hofberg ◽  
Lee C Heinrichs ◽  
Gene A Gentry
Keyword(s):  
Coefficient Of Variation ◽  
Chromatographic Method ◽  
Collaborative Study ◽  
Internal Standard ◽  
Peak Height ◽  
Matched Pair ◽  
Flame Ionization ◽  
Liquid Chromatographic Method ◽  
Two Samples ◽  
Liquid Chromatographic

Abstract A gas-liquid chromatographic method for the determination of propazine in wettable powder formulations containing about 80% active ingredient was collaboratively studied, using a matched pair scheme. The propazine was extracted from the powder with chloroform, with dieldrin as an internal standard, and chromatographed on Carbowax 20M, using a flame ionization detector. Two samples were analyzed using peak height measurements with the following results (13 collaborators): 1.2% overall coefficient of variation and 1.2% coefficient of variation for the random error. Statistical evaluation of these factors reveals no evidence of systematic error contribution. The method has been adopted as official first action.

High Pressure Liquid Chromatographic Analysis of Chlorpyrifos Containing Insecticidal Formulations: Collaborative Study

1981 ◽  
Vol 64 (3) ◽  
pp. 628-634 ◽  
Author(s):  
Norman E Skelly ◽  
David J Jackson ◽  
Phyllis K Anderson ◽  
◽  
J B Audino ◽  
...  
Keyword(s):  
High Pressure ◽  
Chromatographic Analysis ◽  
Collaborative Study ◽  
Internal Standard ◽  
High Pressure Liquid Chromatographic ◽  
Coefficients Of Variation ◽  
Liquid Chromatographic Method ◽  
Liquid Chromatographic Analysis ◽  
Standard Solution ◽  
Liquid Chromatographic

Abstract A high pressure liquid chromatographic method for determining chlorpyrifos was collaboratively studied. Three liquid and 2 solid formulations were analyzed by 12 collaborators. Samples were weighed and diluted with acetonitrile containing the internal standard, 1,4-dibromonaphthalene. Chlorpyriphos is separated on a Zorbax ODS column with acetonitrile- water-acetic acid (82 ± 17.5 ± 0.5) at 2 mL/min and monitored at 300 nm. Clay samples are extracted with the internal standard solution by agitation for 5 min. Coefficients of variation ranged from 1.28 to 2.40%. Results of all 12 collaborators fell within the 5% two-tail limits. The method has been adopted official first action.

Isomer Specific Assay of Ester and Salt Formulations of 2,4-Dichlorophenoxyacetic Acid by High Pressure Liquid Chromatography: Collaborative Study

1978 ◽  
Vol 61 (5) ◽  
pp. 1163-1165 ◽  
Author(s):  
Timothy S Stevens ◽  
Norman E Skelly ◽  
Robert B Grorud
Keyword(s):  
High Pressure ◽  
Collaborative Study ◽  
Internal Standard ◽  
Dichlorophenoxyacetic Acid ◽  
High Pressure Liquid Chromatographic ◽  
Coefficients Of Variation ◽  
Standard Solution ◽  
2,4 Dichlorophenoxyacetic Acid ◽  
Liquid Chromatographic

Abstract A high pressure liquid chromatographic (HPLC) assay of ester and salt formulations of 2,4-D has been collaboratively studied. The method is specific for 2,4-D isomer and resolves all known impurities from 2,4-D and the internal standard p-bromophenol. In situ saponification, at room temperature, is performed by adding a combined saponification-internal standard solution to ester products. The same saponification- internal standard solution is added to amine salts and the analytical standard. The injected aqueous potassium salt solution of 2,4-D is then converted to the acid form by an acidic buffered mobile solvent of 20% acetonitrile in water. Optimum chromatography is attained by a mobile solvent pH of 2.95 in a reverse phase microparticulate column, by ion suppression. Each of the 9 collaborators received 3 different ester and 2 different amine formulations of 2,4-D. The coefficients of variation of 2,4-D acid equivalent ranged from 1.22 to 1.59%. The method has been adopted as official first action.

Modification of the AOAC Gas-Liquid Chromatographic Method for Indole in Shrimp: Collaborative Study

1982 ◽  
Vol 65 (4) ◽  
pp. 842-845
Author(s):  
Theodore L Chambers ◽  
◽  
E C Netz ◽  
K Ogger
Keyword(s):  
Silica Gel ◽  
Chromatographic Method ◽  
Collaborative Study ◽  
Internal Standard ◽  
Current Method ◽  
Peak Height ◽  
Modified Method ◽  
Liquid Chromatographic Method ◽  
Gas Chromatographic Method ◽  
Liquid Chromatographic

Abstract Several changes were suggested for standardization of the AOAC official final action gas chromatographic method for the determination of indole in shrimp. In a collaborative study, 3 FDA laboratories compared the modified method with the current method. At a 95% confidence level, the same results were obtained for each respective sample by the AOAC or the modified method, which had the following changes. The cleanup column was standardized by drying the silica gel for 2 h at 125°C and equilibrating with 3 g of water/25 g of silica gel. Concentrated ethyl acetate shrimp extracts were treated with anhydrous sodium sulfate before column cleanup and indole was eluted from the column with 15% ethyl ether/hexane. A reduced amount of the internal standard, 2-methylindole, was used to improve peak height measurements at the 25 μg% indole level. The modified method has been adopted official first action to replace method 18.075.

Gas-Liquid Chromatographic Determination of Tetradif on Technical and Formulations: Collaborative Study

1981 ◽  
Vol 64 (4) ◽  
pp. 829-832
Author(s):  
Bram Van Rossum ◽  
Albertus Martijn ◽  
James E Launer ◽  
◽  
E C Calamita ◽  
...  
Keyword(s):  
Collaborative Study ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Flame Ionization ◽  
Coefficients Of Variation ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract The gas-liquid chromatographic determination of tetradifon technical and formulations was collaboratively studied in duplicate with 12 laboratories. Six samples were dissolved in dichloroethane with n-hexacosane as the internal standard, chromatographed on a column of 3% SE-52, and detected by flame ionization. The average coefficients of variation were 1.2% for the 2 technical samples, 1.6% for the 2 wettable powders, and 1.5% for the 2 emulsifiable concentrates. The method has been adopted official first action.

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

1985 ◽  
Vol 68 (3) ◽  
pp. 586-589
Author(s):  
Stephen C Slahck
Keyword(s):  
Collaborative Study ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Normal Phase ◽  
Coefficients Of Variation ◽  
Liquid Chromatographic Method ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic ◽  
Technical Products

Abstract A liquid chromatographic method for the determination of triadimefon (Bayleton™) in triadimefon technical and formulated products has been developed and subjected to a collaborative study with 7 participating collaborators. Formulations were extracted with mobile solvent and analyzed by normal phase chromatography, with 4-chlorophenyl sulfoxide as an internal standard. Collaborators were furnished with standards and samples of technical products, 50% wettable powders, and 25% wettable powders for analysis. Coefficients of variation of the values obtained on these samples were 1.42, 0.82, and 1.05%, respectively. The method has been adopted official first action.

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