Sequential thin-layer chromatography of phosfolan, mephosfolan and related compounds

A sequential thin-layer chromatographic method (STLC) has been developed to analyze the two organophosphorus insecticides phosfolan (O,O-diethyl 1,3-dithiolan-2-ylidenephosphoramidate) and mephospholan (O,O-diethyl 4-methyl-1,3-dithiolan-2-ylidenephosphoramidate) and some of their possible degradation products. Gelman type SA, Instant Thin Layer Chromatography (ITLC) silicic acid-impregnated glass fiber sheets were first developed up to 6 cm with the primary solvent 2-butanone-1-butanol-water (9:3:1), then after drying, to 16 cm with the secondary solvent acetonitrile-n-hexane-benzene-acetic acid (80:40:40:1). This two-solvent sequential system separated each insecticide from its corresponding metabolites. The R1 values were: phosfolan, 0.69; ethylene dithioimido-carbonate hydrochloride, 0.08; ethylene dithiocarbonate, 0.90; potassium thiocyanate, 0.40; mephosfolan, 0.76; O,O-diethyl 4-hydroxymethyl-1,3-dithiolan-2-amidate, 0.83; propylene dithioimidocarbonate hydrochloride; 0.15 and propylene dithiocarbonate, 0.87.