Determination and Residues Level of Emamectin Benzoate in Tea Using HPLC with Fluorescence Detection

Abstract

Tea is consumed throughout the world, both for pleasure and therapeutic purpose. Most people will be unaware of their involuntary exposure to residues of pesticide lingering in processed tea and so possibly transferring into infusion of tea. The objective of this trial was not only to provide a simple residue analytical method to evaluate the safe application rate of emamectin benzoate for tea crops but also suitable dosage in tea crop. The residues of emamectin benzoate were deter- mined by high performance liquid chromatography equipped with fluorescence detector. Tea samples extracted with ace- tone/water (70:30 v/v), the extract were cleaned up by liquid - liquid extraction under the fortified level 0.02 µg/mg to 2.0 µg/mg, the recovery ranged from 80.90 % to 115.72 % for black tea, 82.72 % to 106.06 % for sundried green leaves, 83.85 % to 90.64 % for tea brew and 86.33 % to 104.19 % for soil. The limit of detection and limit of quantification of the method were 0.01 µg/mg and 0.02 µg/mg.