Residues of Thiacloprid in/on Apple and Tea

Dissipation of thiacloprid, a new chloronicotinyl insecticide, in/on apple fruits, green tea shoots, black tea and tea infusion was studied to assess its risk. The samples were extracted with acetone: water mixture (3:1), partitioned with cylcohexane: ethyl acetate mixture (1:1) and cleaned over silica column. The residues were quantified by using HPLC equipped with C₁₈ column and UV detector at 242 nm wave lengths. Thh limit of determination (LOD) for apple fruit, soil and green tea was 0.05, 0.1 and 0.001 mg kg⁻¹, respectively. The results indicated that the thiacloprid residues dissipates rapidly and does not accumulate in apple and tea. The half-life of thiacloprid residue on apple fruits ranged between 4.1–4.6 days and 3.8–4.1 days at application rates of 120 and 240 g ai ha⁻¹, respectively. On green tea shoots, the half- life values were around 3.3 days.