A high-performance liquid chromatography (Agilent 1100 HPLC system, USA), with quaternary pump, thermostat ompartment for the column and photodiode array detector was used. Separation was carried out on a carbon 18 (250 4.6 mm, 5 lm). The mobile phase was acetonitrile: water (60/40 v/v) at a flow rate of 0.7 mL min1. Detection wavelength was set at 254 nm. The retention time of thiamethoxam was about 4.05 min. Residues were estimated by comparison of peak area of standards with that of the unknown or spiked samples run under identical conditions.