毛细管气相色谱法测定茶叶中有机氯农药残留的方法研究

Study of Organochlorine Pesticides in Tea with Capillary Column of Gas Chromatography

目的 研究毛细管柱在程序升温条件下测定茶叶中六六六、滴滴涕农药残留的最佳条件，探索测定有机氯农药残留的方法。方法 采用电子捕获-气相色谱法（ECD-GC）OV-17中等极性毛细管柱。程序升温起始温度185℃，10min后，以5℃／min速率升至230℃，保持15min，进样器温度220℃、检测器温度260℃。结果在0．002-0．02ug／ml范围内呈良好的线形关系。六六六4个异构体（α-HCH、γ-HCH、β-HCH、δ-HCH）相关系数分别为0．9993、0．9999、0．9998、0．9999）DDT4个异构体的相关系数（P，P’- DDE、O，P’- DDT、P，P’- DDD、P，P＇-DDT）为0．9990、0．9993、0．9991、0．9974。其相对标准偏差RSD（％）分别为1．4％～3．0％，回收率为94．8％～108．0％。结论本法准确、可靠，适用于各类食品中六六六、DDT残留量的测定。

Objective To explore the best condition for detecting organochlorine pesticides in tea with PTGC. Methods The dectron capture detector - gas chromatograph （ ECD - GC ） was applied. The programming temperatures were as follow： initial temperature was 185℃. then the temperature was raised to 230℃ at speed of 5℃/min. keeping 230℃ for 15min. Temperature of injector was 220℃. Temperature of detector was 260℃. Results The linear range and eoefficient of liner correlation was 0.002 - 0.02ug/ml. The correlation coefficients of four isomers （ HCH ） （ α - HCH,γ- HCH, β- HCH, δ- HCH ） was 0. 9993,0. 9999,0. 9998,0. 9999 ; The correlation coefficients of four isomers （ DDT ） （ P. P＇- DDE, O. P＇- DDT, P. P ＇- DDD, P. P ＇- DDT ） was 0. 9990,0. 9993 ,0. 9991,0. 9974. The relative standard deviation was 1.4% - 3.0%. The recovery rate of the method was 94.8% - 108.0%. Conclusions The result showed that the method was accurate and credibility. It could be applied for determination of HCH and DDT residues in foods.