同位素稀释电感耦合等离子体质谱法测量鱼样中的总汞

Determination of Mercury in Fish by Isotope Dilution Inductively Coupled Plasma-Mass Spectrometry

发展了一种条件温和的提取鱼样中总汞的前处理方法,并建立了同位素稀释电感耦合等离子体质谱(ID-ICP-MS)分析鱼样中总汞的方法。对ID-ICP-MS测量过程中的主要误差来源进行了讨论,使用铅同位素标准参考物NIST SRM 981对测量汞同位素过程中的死时间和质量歧视效应进行了校正。对两种标准参考物(金枪鱼肉IAEA436和角鲨鱼肝NRCC DOLT-3)中的总汞用ID-ICP-MS进行了测定。IAEA436和DOLT-3总汞的测定结果分别为4.23±0.06mg/kg和3.33±0.05mg/kg,与标准值相符。此外,建立的前处理方法可以有效地降低测量过程中汞在系统中产生的“记忆效应”,有利于ID-ICP-MS的应用。

A method for mild extraction and subsequent determination of total mercury in fish by isotope dilution inductively coupled plasma-mass spectrometry （ID-ICP-MS） has been developed. The errors in the measurement of mercury isotope ratio were discussed. The dead time and mass bias induced by the system of ICP- MS were corrected by use of lead isotopic certified reference material NIST SRM 981. The established method was validated by determination of total mercury in two certified reference materials, IAEA 436 （Tuna） and NRCC DOLT-3 （ Dogfish Liver）. The contents of total mercury in IAEA 436 and DOLT-3 were 4.23± 0.06 and 3.33 ± 0.05 mg/kg, respectively, which were in agreement with the certified values. The extraction method was suitable for the determination of mercury by ID-ICP-MS since the memory effect of mercury in the system could be efficiently eliminated.