DETERMINATION OF RESIDUES OF 2-METHYL-2-(METHYLTHIO)PROPIONALDEHYDE O-(METHYLCARBAMOYL)OXIME (UC-21149 TEMIK) ITS SULFOXIDE AND ITS SULFONE BY GAS CHROMATOGRAPHY

Residues of 2-methyl-2-(methylthio)propionaldehyde O-(methylcarbamoyl)oxime (UC-21149, Temik), its sulfoxide, and its sulfone were determined in oranges, apples, sugar beets, and potatoes by gas chromatography with a commercial flame photometric detector highly specific for sulfur. Liquid chromatography of the plant extracts on a Florisil-Nuchar C 190N column served both as a satisfactory cleanup and as a method of separating the three compounds. Gas chromatographic analysis of the sulfoxide and sulfone fractions was accomplished on a packing with a mixed liquid phase (DC 200 and Carbowax 20M). Temik, because of its short retention time, was oxidized to its sulfone with a solution of hydrogen peroxide in acetic acid before gas chromatography. Temik oxidizes readily to its sulfoxide in plants, and even in fortified extracts; therefore, extracts should be analyzed without delay. As little as 2 ng. of the pure standards or 0.01 p.p.m. in crops was detected. © 1968, American Chemical Society. All rights reserved.