Fate of malathion and chlorpyrifos methyl in rough rice and milling fractions before and after parboiling and cooking.

Long-grain rough rice treated with malathion (14 ppm) or chlorpyrifos methyl (Reldan) (6 ppm or 12 ppm) was sampled after 1,6, and 12 wk. Samples from each treatment were processed raw or were parboiled with fresh steeping water, once-used, and twice-used steeping water. Three replicates of rough rice and of each milling fraction were preserved, and three of milled rice were cooked. Chemical residues were measured on rough rice, hulls, brown rice, bran, milled rice, and cooked rice. Parboiling reduced residues on rough rice and hulls but tended to increase residues in the other fractions. Residues of Reldan in bran were substantially increased by parboiling. Doubling the amount of Reldan applied to rough rice approximately doubled the residues found in the milling fractions. Small amounts of the protectants survived all processing including cooking. Residues of malathion in cooked rice averaged about 0.016 ppm in nonparboiled and 0.013 ppm in parboiled rice. Residue of Reldan in cooked rice was commensurate with the amount applied to rough rice. When applied to rough rice at 6 ppm, residues of Reldan in cooked rice averaged 0.05 ppm in nonparboiled rice and 0l.065 ppm in parboiled rice. When applied to rough rice at 12 ppm, residues in cooked rice averaged .053 ppm in nonparboiled rice and 0.15 ppm in parboiled rice. Legal tolerances were not exceeded in any milling fraction. Reuse of the steeping water had little or no effect on residues.

Gas chromatographic determination of CCRL583 perfluorinated alcohol fumigant residues.

A gas chromatographic method is described for the determination of CCRL583 (1,1,1,3,3,4,4,4-octafluoro-2-(trifluoromethyl)-2-butanol). The sample is extracted with acetonitrile and cleaned up by liquid-liquid extraction, first with a basic aqueous solution and finally with an acid aqueous solution. The final organic layer is injected into a gas chromatograph equipped with a column packed with terephthalic acid-terminated Carbowax 20M. Recovery of CCRL583 from fortified wheat and peanuts was 91-108%.

Rapid cleanup procedure for gas-liquid chromatographic determination of chlorpyrifos-methyl residues in cat food.

A simple and rapid gas-liquid chromatographic (GLC) method was developed for the determination of residues of chlorpyrifos-methyl in dry cat food. Cat food fortified with chlorpyrifos-methyl was extracted with acetone and cleaned up on a modified acetonitrile-on-Florisil partitioning column. The chlorpyrifos-methyl was determined by GLC with a flame photometric detector. Results were compared with those for known standards that had undergone the same cleanup procedure. The quantitative electronic integration limit of determination was 0.03 pp. Average recoveries for 5 analyses at fortification levels from 0.052 to 51 ppm ranged from 90 to 102% and averaged 97%.

Determination of pirimiphos methyl in formulations by high performance liquid chromatography.

A simple and rapid method for the determination of pirimiphos methyl (O-[2-(diethylamino)-6-methyl-4-pyrimidinyl] O,O-dimethyl phosphorothioate) in formulations by high performance liquid chromatography is described. The sample is dissolved in methanol, and biphenyl is added as an internal standard. Then the sample is chromatographed by reverse phase chromatography on a Zipax octadecylsilane column. A 4 mul injection containing 0.01% pirimiphos methyl produces a 50% full scale peak at the maximum absorbance at 254 nm.

Gas-liquid chromatographic determination of m-phenoxybenzyl cis, trans-(+/-)-3-(2,2-dichlorovinyl)-2-2-dimethylcyclopropanecarboxylate in aqueous formulations.

A simple and rapid gas-liquid chromatographic (GLC) method was developed for the analysis of aqueous solutions of FMC 33297 (mphenoxybenzyl cis,trans-(+/-)-3-(2,2-dichlorovinyl) - 2,2 - dimethylcyclopropanecarboxylate). The compound is extracted from aqueous solution with benzene and cleaned up by liquid chromatography. The sample extracts are analyzed by GLC with a flame ionization detector and quantitated by comparing integrator counts of extracts with those of standards. Recoveries of FMC 33297 were 90-100%. The method has good precision (the standard deviation for 4 determinations of a 0.002394% formulation was 6 X 10(-6)) and is sensitive to 0.00004% active ingredient by weight,

Gas chromatographic determination of hydrazoic acid.

A gas chromatographic procedure was developed for the determination of hydrazoic acid. Two possible columns were evaluated. The limits of detectability were 1.5 ng, or approximately 0.05%, in aqueous solution (w/v) and 2 mg per liter in air.

The determination of BHT in resmethrin by high-pressure liquid chromatography.

A method was developed to determine the amount of butylated hydroxy toluene in resmethrin and resmethrin formulations by high-pressure liquid chromatography.

Gas-liquid chromatographic determination of resmethrin in corn, cornmeal, flour, and wheat.

A gas-liquid chromatographic (GLC) method was developed for the determination of residues of resmethrin ((5-benzyl-3-furyl)methyl cis-trans-(+/-)-2,2-dimethyl-3-(2-methylpropenyl)-cyclopropanecarboxylate) in corn, cornmeal, flour, and wheat. The commodity, fortified with resmethrin, was extracted by tumbling with pentane and transferred to acetonitrile, the fat was partitioned off, and the sample was chromatographed with 3% ethyl acetate in pentane on Florisil containing 0.5% water. The resmethrin residue was determined by GLC with a flame ionization detector. The results were compared with known standards that had undergone the same cleanup procedures. The method was sensitive to concentrations of resmethrin to 0.2 ppm, recoveries averaged 83%, and reproducibility was good.