Automated determination of inorganic mercury in blood after sulfuric acid treatment using cold vapour atomic absorption spectrometry and an inductively heated gold trap

Abstract

Inorganic mercury (InoHg) in whole blood and erythrocytes was determined by cold vapour atomic absorption spectrometry (CVAAS) after overnight treatment with sulfuric acid at 45 °C and reduction with Sn^II in the acidic mixture. Total mercury (TotHg) was determined after digestion with a mixture of nitric and perchloric acids. Mercury vapour was preconcentrated on an amalgamation trap made of gold wire. The mercury was rapidly released by inductive heating of the trap. InoHg could be determined specifically in the presence of methylmercury (MeHg). The concentration of MeHg could be calculated by subtracting the concentration of InoHg from that of TotHg. Calculated concentrations of MeHg in erythrocytes showed a strong correlation with the results of a gas chromatographic method, though a discrepancy in calibration was indicated. The detection limits (3 s) in blood (0.5 g) were 0.06 ng g^–1 for TotHg and 0.04 ng g^–1 for InoHg and s_r for a 5 ng g^–1 whole blood sample was 2%(n= 10) for both TotHg and InoHg.