Gas-chromatographic determination of trace <Emphasis Type="Italic">O</Emphasis>-isobutyl-2-<Emphasis Type="Italic">S</Emphasis>-(<Emphasis Type="Italic">N,N</Emphasis>-diethylamino)ethyl ester of methylthiophosphonic acid (VX-type compounds) in slime

A procedure was proposed for the gas-chromatographic determination of trace O-isobutyl-S-2-(N,N-diethylamino)ethyl ester of methylthiophosphonic acid (mixed ester, ME) in burning products formed after the detoxication of elements in building constructions, personal protection equipment, waste degassing solutions, and other production wastes (slime) at a level of (1.0–10.0) × 10^?8 mg/g. The procedure is based on the extraction of ME from an analyzed material with a mixture of aqueous solutions of monoethanolamine and NaOH, its back extraction to hexane, the evaporation of the hexane layer (with the addition of HCl) to dryness, the transformation of ME into methyl ester of O-isobutylmethylphosphonic acid with the use of methanol in the presence of AgNO₃, and the chromatography of the derivative on an open tubular column with the chemically modified HP-INN OWax stationary phase with the use of a flame-photometric detector.