Determination of ethylenethiourea in grapes and wine

Residues of ethylenethiourea (ETU) in grapes and wine were determined by capillary gas chromatography and paper chromatography, without a cleanup step, and after derivatization to S-benzyl-ETU. The detection limit was 0.0002 mg/kg for flame ionization detection, 0.008 mg/kg for paper chromatography with photodensitometric evaluation of the detected spot. Results were compared with a generally used GC method specifying electron capture detection of trifluoroacetylated S-benzyl-ETU. The recoveries of ETU in grapes and wine at different concentration levels were determined. ETU residues were determined in treated grapes but no residues were detected in wine.