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

A method for mild extraction and subsequent determination of total mercury content 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 the use of lead isotopic certified reference material NIST SRM 981. The established method was validated by determining total mercury content in two certified reference materials, IAEA 436 (Tuna) and NRCC DOLT-3 (Dogfish Liver). The results of total mercury presented in IAEA 436 and DOLT-3 were 4.23 ± 0.06 and 3.33 ± 0.05 mg kg−1, respectively, which were in agreement with the certified values. The extraction method was suitable for the determination of mercury by ID-ICP-MS because the memory effect of mercury in the system could be efficiently eliminated.