微波辅助萃取-气相色谱法测定茶叶中的有机磷农药

Determination of Orgnophosphorus Pesticides Residues in Tea by Microwave Assisted Extraction-Gas Chromatography

建立了微波辅助萃取–气相色谱法测定茶叶中甲胺磷、乐果、毒死蜱、水胺硫磷、三唑磷5种有机磷农药残留量的分析方法。样品用乙酸乙酯微波辅助提取,提取液经分散固相萃取法(DSPE)净化,用气相色谱配FPD检测器测定,外标法定量。结果表明农药混合标准溶液在0.01～0.5μg/mL范围内线性良好(r>0.999),方法的检出限为0.005～0.01 mg/L,在0.05,0.125,0.5μg/mL 3个水平添加平均回收率为63.3%～99.9%,测定结果的相对标准偏差为5.1%～8.2%(n=6)。该方法适合于茶叶中多种有机磷农药残留量的同时检测。

A method of microwave-assisted extraction（MAE） followed by gas chromatography（GC） for the determination of five organophosphorus pesticides of methamidophos, dimethoate, chlorpyrifos, isocarbophos, triazophos residues in tea was developed. Sample was extracted by microwave-assisted extraction with ethyl acetate, and then cleaned up by dispersive solid-phase extraction（DSPE）, detected by gas chromatography with FPD using external standard method. The linear relationship of this method was fine between 0.01μ g/mL and 0.5 μ g/mL（r 〉 0.999）. The detection limits for organophosphorus pesticides were 0.005-0.01 mg / L. The recoveries ranged from 63.3% to 99.9% at three spiked levels of 0.05,0.125,0.5 mg / kg and the relative standard deviations of determination results were in the range of 5.1%-- 8.2%（n=6）. The method was suitable for simultaneous determination of orgnophosphorus pesticides residues in tea.