气相色谱法测定水产品中痕量甲基汞的方法研究

Study on the determination method of methyl mercury in aquatic products by gas chromatography

目的建立一种快速、简便、灵敏的气相分析检测方法测定水产品中痕量甲基汞的含量,为水产品中痕量甲基汞残留量的测定方法改进提供新的方案。方法样品与氯化钠混合研磨成半固态状,加入盐酸酸化,用二氯甲烷萃取,萃取液过滤后作为测试样品。本实验采用气相色谱法测定样品,选择DB-1701毛细管柱(30 m×0.32 mm,1.00μm),程序升温后,通过电子捕获检测器进行检测,用外标法定量。结果甲基汞在0.17μg/ml^0.85μg/ml线性关系良好,r为0.998 0,方法的最低检出限为0.081 mg/kg,相对标准偏差(RSD)<1.5%,甲基汞加标样品的平均回收率为66.47%~71.47%。结论本实验提供的操作方法简便、灵敏,色谱峰分离度良好,峰形尖锐,重现性良好,系统适用性良好,且实验对环境污染较小,对实验人员的健康危害较小。本方法可为测定水产品中痕量甲基汞的检测提供可选的新方法。

Objective To establish a rapid,simple and sensitive detection method for determination of trace amounts of methylmercury residues in aquatic products so as to provide new ways to improve the method. Methods Sample mixed with sodium chloride was grounded into semi- solid,after adding hydrochloric acid and extracting with dichloromethane,the extract was filtered as a test sample. Gas chromatography was used for the determination in this experiment with DB- 1701 capillary column（ 30 m × 0. 32 mm,1. 00 μm）,electron capture detector was used to determine,using procedures heating method,and external standard measurement was used to quantify. Results The linear range of methylmercury in 0. 17 μg / ml- 0. 85 μg / ml had good linear relationship,r = 0. 998 0,the detection limit was 0. 081 mg / kg,RSD of precision was less than 1. 5%,the average recovery of samples was 66. 47%- 71. 47%. Conclusion The method of operation in this experiment is simple,sensitive,and of good chromatographic peak separation,good reproducibility,good system suitability,less environmental pollution,and less hazards to health laboratory person. So it can provide a viable and new method for detecting residues of methylmercury in aquatic products.