Gas-chromatographic determination of pesticide residues after clean-up by gel-permeation chromatography and mini-silica gel-column chromatography6. Communication(*): Replacement of dichloromethane by ethyl acetate/cyclohexane in liquid-liquid partition and simplified conditions for extraction and liquid-liquid partitio.

A new extraction and partition step was introduced into the well established multi-residue method of Specht and Tillkes (DFG method S 19) replacing dichloromethane by ethyl acetate/cyclohexane (1+1). In addition, more simple working conditions were obtained. Results of fortification experiments with organochlorine, organophosphorus and organonitrogen pesticides showed good agreement with those obtained by the formerly published method.