气相色谱法测定禽蛋中微量有机氯农药及多氯联苯的残留

Determination of Organochlorine Pesticides and Polychlorinated Biphenyl Congeners Residues in Eggs by Gas Chromatography with Electron Capture Detection(GC-ECD)

建立了以正己烷振荡提取 ,以PCB2 和PCB2 0 9为内标的快速检测禽蛋中微量有机氯污染物的气相色谱法。与传统的索氏提取法相比 ,在保证足够的准确度、精确度和灵敏度的前提下 ,具有前处理简单、测试成本低、标本用量少的特点 ,而且可同时测定有机氯农药和典型的多氯联苯类化合物的残留 ,特别适于检测食品中的微量有机污染物。用该方法测试的结果表明 ,标准全蛋粉添加ng/g级待测物时 ,各种待测物的回收率为 84 31%～ 116 77% (3次测定平均值 ) ;相对标准偏差为 6 %～ 18% (7次测定平均值 ) ;最低检出量为 0 0 7ng/g～ 0 35ng/g。中国部分城市市售鸡蛋中的有机氯农药以p ,p′ DDE的检出量最高 ,p ,p′ DDT次之 ;多氯联苯的检出量很低 ,大多数样品中多氯联苯的总检出量低于 10ng/g。在所检出的多氯联苯中 ,绝大部分为含氯低的 (氯原子数为 3～ 5 )的氯化物。

A procedure of clean-up with H_2SO_4 after extraction with a shaking machine using n -hexane, and fast determination of some organochlorine residues in eggs by GC-ECD with PCB_2 and PCB_ 209 as internal standards was established. The test results showed that with this method satisfactory recoveries(84.31%-116.77%), relative standard deviation (6%-18%) and detection limits (0.07 ng/g-0.35 ng/g) could be obtained. In comparing with the Soxhlet method, this method is simpler in pre-treatment, lower in cost and less in sample amount. It can determine organochlorine pesticides and some PCBs in the same extract, simultaneously with enough accuracy, sensitivity and permissible RSD. It is a suitable procedure for determining micro-amounts of organochlorine pollutants in foods. The results showed that pp′ -DDE was detected in maximum; pp′ -DDT next; and PCBs very little, that were usually less than 10 ng/g in the eggs from some Chinese markets. It was found that most of PCBs in eggs were the congeners with 3-5 chlorine atoms.