基质固相分散萃取-气相色谱法检测茶叶中有机氯农药残留

Determination of organochlorine pesticide in teas by matrix solid-phase dispersion entraction and gas chromatography

目的:探讨基质固相分散萃取技术,改进茶叶中有机氯农药残留的测定方法,研究使之更便捷、高效和经济的具体操作模式。方法:将样品与基质填料按一定比例充分研磨,然后装柱、洗脱、浓缩、定容,供气相色谱检测茶叶中有机氯农药的残留。结果:各填料对农药吸附损失后的回收率达到要求,利用0.8g活性炭除去色素,利用0.5g中性氧化铝和0.5g弗罗里硅土净化,选择样品与弗罗里硅土的比例为1:2,利用乙酸乙酯+石油醚(1∶1,V∶V)以1.0 ml/min的流速洗脱,最后该方法相对标准偏差均在0.95%～22.43%,回收率均在67.7%～106.6%。结论:根据基质相关实验结果,选择一定比例的几种混和物作为填料,通过适合的有机溶剂以及淋洗速率,将洗脱液浓缩后供气相色谱测定,可以得出本方法适用于茶叶中有机氯农药残留的检测。

Objective ：To study the application of the matrix solid-phase dispersion extraction technology, to improve the determination method of pesticide residues in teas and to make more convenient,efficient and economical specific mode of operation.Methods： The sample and matrix filler were fully grinded with certain proportion, and then packing column,elution, concentrating,constant volume for detection of organochlorine pesticide residue in teas by gas chromatography.Results：The recovery of various fillers after pesticide absorption losses met the requirement.Using 0.8 g activated cabon and 0.5g florisil to purification,and the ratio of samples and mandrax Florida silicon soil was 1：2, using ethyl acetate＋petroleum ether（1：1, V：V） with flow rate of 1.0 mL/min for elution. The relative standard deviation was 0.95%-22.43%,and the recovery rate was 67.7%-106.6%.Conclusion：According to matrix related experimental results,selecting several mixtures with certain proportion as filler, through the appropriate organic solvents and leaching rate,concentrating eluate for gas chromatography determination,this method can be applied to the detection of organ ochlorine pesticide residues in teas.