气相色谱法测定蔬菜中22种多氯联苯残留量

GC Determination of Residual Amounts of 22 Polychlorobiphenyl′s in Vegetables

用丙酮及正己烷(1+1)混合溶剂在ASE 200型微波提取仪中提取蔬菜样品,所得提取液经无水硫酸钠脱水后蒸缩至近干,用正己烷熔解残渣,所得溶液通过弗罗里硅柱纯化。用正己烷淋洗弗罗里硅层析柱,收集合并淋出液,蒸缩后定容为2.0 mL,供气相色谱测定。所测定的22种多氯联苯的质量浓度与各自对应的峰面积在一定范围内呈线性关系,由各线性回归方程求得的相关系数均在0.999以上。以大白菜样品作基体,加入22种多氯联苯单体的混合标准溶液作方法的回收试验,测得回收率在84.0%～99.0%之间。在一种浓度的混合标准溶液水平上进行6次测定,求得相对标准偏差在0.90%～2.69%之间。

Vegetable sample was extracted with a mixture of acetone and n-hexane（1＋1） in the ASE 200 Microwave Extractor.The extract was dehydrated with anhydrous Na2SO4 and evaporated to near dryness.The residue was dissolved in n-hexane and purified by passing through Florisil column.The column was eluted with n-hexane,and the eluates collected were combined and evaporated to a volume of 2.0 mL which were used for GC analysis.Linear relationships between values of peak area and mass concentration of monomers of the 22 polychlorobiphenyl′s（PCBP′s） were obtained in definite ranges,with correlation coefficients over 0.999 as shown by their linear regression equations.Tests for recovery were made by adding mixed standard solutions of the 22 PCBP monomers to a same matrix sample of Chinese cabbage,values of average recovery found were in the range of 84.0% to 99.0%.Values of RSD′s（n=6） found at one concentration level of the mixed standard solution were in the range of 0.90%-2.69%.