Removal of imidacloprid and acetamiprid in tea (Camellia sinensis) infusion by activated carbon and determination by HPLC

Activated carbons were applied to the removal of imidacloprid and acetamiprid from tea infusion and both pesticides were determined by HPLC in this study. Results presented that the YQFB, an activated carbon with large BET surface area and more mesopores was effective for the removal of both pesticides from tea infusion. The removal rates were significantly (p ≤ 0.05) affected by absorbent dosage, adsorption time, temperature, tea concentration and initial concentration of pesticide. Removal rates of both pesticides were improved with the dosage increased and the adsorption time prolonged, while decreased as the increase of tea concentration and initial concentration of pesticides. The maximum removal rates were 85.0% for imidacloprid and 85.7% for acetamiprid. The adsorption of both pesticides by YQPB followed the pseudo-second-order kinetics model well. The quality of tea infusion after activated carbon treatment was analyzed and results revealed that the retention rates of most components were higher than 85% and the stability of tea infusion was not significantly (p > 0.05) affected by activated carbon treatment. The present study found a low-cost and effective way to remove imidacloprid and acetamiprid from tea infusion, and it has the potential to be applied to the ready-to drink tea beverages production in industrial scale.