加速溶剂萃取-气相色谱法测定茶叶中八氯二丙醚残留量及其不确定度评估  

Evaluation of uncertainty in the determination of bis-(2,3,3,3-tetrachloropropyl) ether in tea leaves by accelerated solvent extraction technique and gas chromatography

作　　者：谭琳[1] 胡秋龙 张建辉 江紫薇[1] 黄忠意 刘璞[2] 

机构地区：[1]湖南农业大学生物安全科技学院,长沙410128 [2]湖南省食品质量监督检测所,长沙410002

出　　处：《农药学学报》2011年第6期621-626,共6页Chinese Journal of Pesticide Science

基　　金：国家自然科学基金资助项目(31101460)

摘　　要：建立了加速溶剂萃取-气相色谱(ASE-GC)法测定茶叶中八氯二丙醚残留量的方法。茶叶样品经加速溶剂萃取仪用正己烷-丙酮(1∶1,体积比)提取,经硅藻土-浓硫酸(10 g∶4.0 mL)净化,以正己烷洗脱并定容,GC-ECD检测,外标法定量。此外,对测定过程中可能引入的不确定度进行了分析和评定。结果表明:在质量浓度为0.010～0.40 mg/L范围内,峰面积与八氯二丙醚的质量浓度成良好的线性关系,相关系数r=0.999 1;八氯二丙醚的添加水平在5～30 ng/g范围内,平均回收率为90.2%,相对标准偏差(RSD)为4.7%,方法的检出限(LOD)为0.005 mg/kg;当茶叶中八氯二丙醚含量为0.053 1 mg/kg时,取置信概率为95%,包含因子k=2,则其扩展不确定度U=0.003 6 mg/kg。通过对不确定度的分析,发现影响测定结果不确定度的主要来源有回收率、测量重复性和标准溶液的配制过程。A method has been developed for the determination of bis-（2,3,3,3-tetrachloropropyl） ether in tea leaves by accelerated solvent extraction technique（ASE） and gas chromatography（GC）.The samples were extracted by accelerated solvent extraction（ASE） using hexane-acetone（1∶1,V/V） as the extraction solvent,purified with celite-sulfuric acid（10 g ∶0.4 mL） using hexane as an eluent.The correlation coefficient in the concentration range at 0.010-0.40 mg/L was 0.999 1,The average recoveries of bis-（2,3,3,3-tetrachloropropyl） ether in tea at 5-30 ng/g fortification level were 90.2%,with relative standard deviations（RSD） of 4.7%.The limit of detection（LOD） of the method was 0.005 mg/kg.Uncertainties originated from the measurement of bis-（2,3,3,3-tetrachloropropyl） ether in tea leaves by ASE-GC method were analysed and evaluated.When bis-（2,3,3,3-tetrachloropropyl） ether content in tea was 0.053 1 mg/kg,the relative uncertainty（UreI） was calculated to be 0.003 6 mg/kg from the experimental data when the designed incredible probability was 95% and factor（k） was 2.The results of uncertainty analyses showed that the recovery rate,repeatability of determination and preparation process of standard solution were the key issues of the testing quality control.

关 键 词：八氯二丙醚 加速溶剂萃取 气相色谱法 茶叶 不确定度 

分 类 号：O657.71[理学—分析化学] X592[理学—化学]