Residue analysis of ethylenethiourea in vegetables by high-performance liquid chromatography with amperometric detection

Summary A method for the residue analysis of ethylenethiourea (ETU) in vegetables by HPLC with amperometric detection was developed. ETU was separated with Nucleosil C₁₈ as stationary phase and methanol-water (5:95, v/v) containing 0.05 mol/l ammonium acetate as eluent. The voltage of the working electrode (glassy carbon) was set at +1150 mV vs. Ag/AgCl. The limit of detection for ETU was found to be 0.3 ng. The method was applied to the determination of trace amounts of ETU in tomatoes and cucumbers. The minimum quantitation level was 0.01 ppm. The method can be performed easily; it is selective and highly sensitive.