High Precision Determination of Mercury Isotope Ratios Using Online Mercury Vapor Generation System Coupled with Multicollector Inductively Coupled Plasma-Mass Spectrometer

In this study, a method for high-precision measurement of Hg isotope ratios by multiple collector inductively coupled plasma-mass spectrometry (MC-ICP-MS) with on-line Hg reduction technique was developed. The procedure was evaluated to obtain high-precision measurements that were good enough to significantly detect the anticipated small differences in Hg isotope compositions in natural samples. Typically, internal precision was better than 0.02%° (1 RSE) on all Hg ratios investigated. The external reproducibility for standard NIST SRM3133 and UM-Almadén secondary solution, nature samples were 0.06%° (2SD) and 0.10%° (2SD) over a period of 7 months, respectively. The extent of fractionation has been investigated in a series of natural samples from different locations in China. The ratio 202Hg/198Hg expressed as δ values (per mil deviations relative to NIST SRM 3133 Hg standard solution) displayed differences from –3.48%° to 0.633%°. These results indicated a wide perspective application of tracing Hg in the environment.