环境样品中多氯联苯残留物的色谱/质谱定量测定

多氯联苯(简称PCB)是全球性的环境污染物之一,实际上它是由一百多种氯化联苯异构体所组成的。为了测定复杂环境样品中的PCB总残留量,Webb等首先提出了“各峰和”定量法,我们亦在先前的工作中采用二种国产PCB标样建立了相应的填充柱色谱定量方法,即分别定量测定样品中各氯化联苯色谱峰所含的PCB量,叠加后得到PCB总残留量。但是有机氯农药的广泛污染经常使PCB的测定受到干扰。我们研究了PCB及几种国内常用有机氯农药的质谱图,找出了一些能相互抗干扰的特征离子,将这些质量色谱图叠加所得的选择离子流可用于定量分析,使我们有可能同时测定几种化合物(见图1),省略了繁杂的化学分离和提纯步骤,缩短了分析时间,避免了处置过程中痕量样品的损失或沾污,增加了测定的可靠性。

QUANTITATIVE ANALYSIS OFPOLYCHLORINATED BIPHENYLS RESIDUES INENVIRONMENTAL SAMPLES BY GC-MS

PCB's are considered one of the world-wide pollutants. In the previous work, two Chinese commercial PCB's references for individual peak quantitation of PCB's residues by electron capture GC, have been established. In this paper, computer-control led multiple ion detection (MID) technique is used in Finnigan 4021 GC/MS instrument to analyse quantitatively PCB's and chlorinated pesticides simultaneously. This method eliminates the complicated and tedious chemical protreatments, and enhances sensitivity to 10-9g or even higher. Here chemically similar o, p-DDE is used as internal standard. The quantitative results of two soil samples by individual peak method demonstrate clearly that o, p-DDE as internal standard reduces the error introduced by solvent extraction and sample injection. It is believed that this method possesses advantages over any other existing methods.