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为快速准确检测土壤中21种低浓度多氯联苯(PCBs)的含量,建立了以丙酮-正己烷(1:1,V/V)为萃取剂超声提取,四通道色谱分离仪对提取液进行分离和净化的前处理方法。采用氮吹法将前处理的样品浓缩至50μL以下,以PCB 54作为内标,利用气相色谱-63Ni微电子捕获检测器(GC-ECD)进行定量测定。土壤中21种PCBs的回收率为68.6%~102.3%,相对标准偏差为2.2%~9.9%,方法检出限为1.21~4.67μg/kg。采用所建方法对长江三角洲地区经长期植物修复后的PCBs污染土壤和无污染的农田土壤进行检测,结果显示,修复后的土壤PCBs总量为99.88±3.97μg/kg,无污染农田土壤PCBs总量为69.01±2.19μg/kg。
In order to rapidly and accurately detect the content of 21 kinds of low concentration polychlorinated biphenyls (PCBs) in soils, an ultrasonic extraction was carried out with acetone-n-hexane (1: 1, V / Pre-treatment methods for separation and purification. The pre-treated sample was concentrated to less than 50 μL by nitrogen blowing and quantitatively determined by GC-63N micro-electron capture detector (GC-ECD) using PCB 54 as an internal standard. The recoveries of 21 PCBs in soil ranged from 68.6% to 102.3% with relative standard deviations of 2.2% -9.9%. The detection limits were 1.21 ~ 4.67 μg / kg. The PCBs contaminated soil and non-polluted farmland soils in the Yangtze River Delta after long-term phytoremediation were tested by the proposed method. The results showed that the total amount of soil PCBs after the restoration was 99.88 ± 3.97μg / kg, The amount was 69.01 ± 2.19 μg / kg.