Rapid determination of ethephon residues in food with headspace gas chromatography

The indirect determination of the pesticide ethephon after reaction to ethylene with headspace gaschromatography on FID and J&W PLOT-column GS Q (30 m, 0,53 mm) is described. To the samples were added 1 ml of acetone and 1 ml of KOH (10 mol/l) and then heated for 6 hours to 60 degrees C, The relative standard deviation is determinated on apples with 11,1% (0,1 mg/kg) and 10,6% (1 mg/kg). The limit of determination is below 0,01 mg/kg. The recovery in apples with additives of 0,1 to 10 mg/kg reaches 91,6 to 112%, The residues in real foodsamples are between 0,005 and 0,04 mg/kg. Residues above the legal limit were not discovered.