毛细管气相色谱法测定绿茶中八氯二丙醚残留量

建立了用毛细管柱气相色谱法测定绿茶中八氯二丙醚（S-421）残留量的方法。绿茶样品用正己烷提取,经硅藻土545（1 g）-浓硫酸（0.4 mL）净化,以正己烷洗脱;经毛细管气相色谱柱DB-1701（30 m×0.32 mm×0.25μm）分离,电子捕获检测器测定,外标法定量。试验结果表明：八氯二丙醚在0.010~0.100 mg/L质量浓度范围内线性关系良好（r=0.999 4）,方法的定量限为0.01 mg/kg;添标水平为0.02,0.04,0.08 mg/kg时,平均回收率在92.9%~97.2%之间,相对标准偏差不大于3.6%。该法操作简单,实验结果准确可靠,可用于绿茶中八氯二丙醚残留量的测定。

Determination of octachlorodipropyl ether residue in green tea by capillary gas chromatography

A gas chromatographic method was developed for the determination of octachlorodipropyl ether（S-421） residue in green tea.Octachlorodipropyl ether was extracted from green tea samples by using n-hexane,purified with celite 545（1 g）-sulfuric acid（0.4 mL） by using hexane as an eluent,and then analyzed by gas chromatography by using DB-1701 capillary column（30 m×0.32 mm×0.25 μm）for separation and electron capture detector（ECD） for detection.The method of external standards was used in determination.A good linear correlation for octachlorodipropyl ether is obtained over the range of 0.010-0.100 mg/L（r=0.999 4）with the limit of quantitation（LOQ） of 0.01 mg/kg.Average recoveries of octachlorodipropyl ether from green tea spike at three concentration levels of 0.02,0.04 and 0.08 mg/kg ranged from 92.9% to 97.2% with relative standard deviation not more than 3.6%.The proposed method is easily operative and accurate for precise determination of octachlorodipropyl ether residue in green tea with satisfactory results.