Abstract: A new method for the simultaneous determination of 4 herbicides (Monuron, Chlortoluron, Diuron and Linuron) was established with MSPD-RP-HPLC. The mixture of tea samples and C₁₈ stuffing were pulverized, then mixed with alumina packed to a syringe column, the extraction and purification of the samples were carried out with one-step using dichloromethane as eluting reagent. The effecting factors of MSPD and conditions of the chromatography were discussed. Under optimum conditions, the linear ranges of Monuron was 0.01~10.0 mg/L with 5 μg/L of the detection limits, and the linear ranges of Chlortoluron, Diuron and Linuron were 0.025~10.0 mg/L with 10 μg/L of the detection limits. The average recoveries of 4 herbicides ranged from 83.5% to100.4% with less than 7.1% of the relative standard deviations in tea samples. The method suggested was simple, rapid, and less interference with high recovery rate, and meet the analytical requirements of herbicide residues in tea.

Key words: MSPD, RP-HPLC, phenylurea herbicides, tea