加速溶剂萃取同步净化-同位素内标-气相色谱-高分辨质谱测定水产品中32种多氯联苯

建立了加速溶剂萃取同步净化-同位素内标-气相色谱-高分辨质谱同时测定水产品中32种多氯联苯含量的方法。通过在加速溶剂萃取仪中加入2 g无水硫酸钠、1 g弗罗里硅土、50 g中性氧化铝作为吸附剂实现同步净化的效果,萃取溶剂为二氯甲烷-正己烷(1∶1,v/v),萃取温度为100℃,循环2次。萃取结束后分别用0.5 mL浓硫酸净化两次,净化液浓缩定容后,采用气相色谱-高分辨质谱测定,同位素内标法定量。32种多氯联苯在0.1~20μg/L范围内平均相对响应因子(RRF)的相对标准偏差(RSD)值(n=7)均小于15%,定量限(S/N=10)为0.3~1.9 ng/kg。在草鱼和海鲈鱼空白基质中做加标回收试验,添加水平为5、20和50 ng/kg,得到的平均回收率为71.9%~119.0%(n=6),RSD为3.5%~19.6%。该方法背景干扰低,灵敏度高,重现性好,回收率稳定,适用于水产品中多氯联苯的检测。

Determination of 32 polychlorinated biphenyls in aquatic products by gas chromatography-high-resolution mass spectrometry with accelerated solvent extraction-purification simultaneously coupled to isotope internal standard method

Gas chromatography (GC)-high-resolution mass spectrometry (HRMS) with accelerated solvent extraction (ASE)-purification simultaneously coupled to the isotope internal standard method is proposed for the determination of 32 polychlorinated biphenyls (PCBs) in aquatic products. Synchronous purification was achieved by adding 2 g of anhydrous sodium sulfate, 1 g of Cleanert Florisil, and 50 g of neutral alumina as the adsorbent to the ASE system. The PCBs were extracted from aquatic product samples using a dichloromethane-n-hexane (1:1, v/v) mixture at 100 ℃ with two extraction cycles. The extracting solution was purified twice with 0.5 mL concentrated sulfuric acid. After concentration to a constant volume, the target compounds were detected by GC-HRMS and quantified by the isotope internal standard method. Under the optimized conditions, the relative standard deviations (RSDs) of the mean relative response factor (RRF) for the 32 PCBs in the range of 0.1-20 μg/L were less than 15%. The limits of quantification were 0.3-1.9 ng/kg. At three spiked levels (5, 20, and 50 ng/kg) in grass carp and sea bass, the recoveries of the 32 PCBs were between 71.9% and 119.0%, with the RSDs varying from 3.5% to 19.6%. This method effectively reduces the matrix interference and shows high sensitivity, good reproducibility, and stable recovery, thus proving useful for the detection of PCBs in aquatic products.