水产品中五氯苯酚及其钠盐含量的气相色谱内标测定法

检测水产品中氯苯酚及其钠盐含量的常规方法存在诸多问题, 建立气相色谱内标检测法可以降低乳化、衍生等前处理过程而造成提取物的损失, 增强方法可操作性和准确性, 降低检测的不稳定性, 通过对前处理方法中衍生温度、衍生产物提取液吹干与否对回收率影响的比较研究和色谱条件的改进, 建立了鲫、鳕、日本沼虾、中华绒螯蟹可食部分中五氯苯酚及其钠盐残留量的气相色谱内标法。样品中的五氯苯酚及其钠盐在酸性介质中全部转化为五氯苯酚, 由正己烷提取, 碳酸钾溶液反萃取, 萃取物经乙酸酐衍生生成五氯苯乙酸酯, 正己烷提取衍生物, HP-5MS (30 m×0.25 mm×0.25 μm)色谱柱分离, 用配备微池电子捕获检测器的气相色谱测定, 以2, 4, 6–三溴苯酚作为内标物, 内标法定量。结果表明: 该方法在0.2~20.0 μg/L范围内线性关系良好, 相关系数R2=0.999 6, 在加标水平为2.0、5.0、10.0、50.0 μg/kg, 内标为50.0 μg/kg, 加标回收率为85.8%~109.0%, RSD为0.8%~9.3%, 最低检测限为0.6 μg/kg。

Determination of residues of pentachlorophenol and its sodium salt in aquatic product by gas chromatography using internal standard method

The aim of this study was to reduce the loss of preliminary treatment of sample such as deriva-tives and emulsification,to enhance the maneuverability and accuracy of method,to promote the in stabil-ity of detection.Residues of pentachlorophenol and its sodium salt in edible tissues of crucian,freshwater shrimp,cod and chinese mitten crab were determined by gas chromatography using internal standard method.Such factors as derivation method,Whether n-hexane was blowed or not for pentachlorophenol and its sodium salt were compared in this paper.Moreover,the chromatographic conditions were surveyed and optimized for detection of the residues of pentachlorophenol and its sodium salt in edible tissues.The target compounds were first extracted two times with n-hexane in an acidic medium,and then back ex-tracted with potassium carbonate solution.The extract was derived with acetic anhydride,and the deriva-tive was extracted with n-hexane.The HP-5MS(30 m×0.32 mm×0.25 μm) column and the micro-cell elec-tron capture detector was used for the determination.This method chooses 2,4,6-TBP as internal standard substance.The working curves were linear(R2=0.9996) in the range of 0.2-20.0 μg/L.When spiked with 2.0,5.0,10.0,50.0 μg/kg of pentachlorophenol and 50 μg/kg of 2,4,6-tribromophenol,the average recov-eries were 85.8%-109.0% and the RSD were 0.8%-9.3%.The detection limit was 0.6 μg/kg.