中文摘要：

采用多接收等离子体质谱（MC-ICP-MS）方法高精度测定了Hg同位素组成。本方法借助在线进样系统,最大程度上克服了同位素干扰和基体效应;采用同位素内标法和样品-标准交叉法以消除仪器自身的质量分馏;通过实验条件（如测定时间、进样量等）的优化,方法的内精度显著提高。研究表明：为保证汞同位素组成的高精度测定,汞最低进样浓度为2μg/L时,内精度〈0.02‰（RSD）。运用本方法对汞标准NISTSRM3133和UM-Almadn实验室内标样长达7个月的测定,结果表明,本方法外精度〈0.06‰（2SD）。此外,对一系列环境样品的同位素组成进行了测定,样品的外精度〈0.10‰（2SD）。测定样品δ202Hg变化范围为-3.48‰～0.63‰,幅度达4.11‰。

英文摘要：

A method was developed for high precision measurement of Hg isotope ratios by multiple collector inductively coupled plasma mass spectrometry（MC-ICP-MS） using an on-line Hg reduction technique.The procedure was evaluated to get 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 Relative standard error,RSE） on all Hg ratios investigated.The external reproduci-bility for standard N IST SRM3133 and UM-Almadén secondary solution,nature samples were 0.06‰ （2SD） and 0.10‰ （2SD） over the course of 7 months,respectively.The extent of fractionation has been investi-gated in a series of natural samples from different locations in China.The ratio 202/198Hg expressed as δ values （per mil deviations relative to NIST SRM 3133 Hg standard solution） was from-3.48‰ to 0.633‰.