【摘要】 称取样品0.200 0g,加入盐酸-硝酸（9+1）混合酸5mL,于沸水浴中加热2h,冷却后加入75g·L^-1硫脲-75g·L^-1抗坏血酸混合溶液5mL,混匀后,用含5g·L^-1酒石酸的3mol·L^-1盐酸溶液定容至25mL,摇匀后供冷原子汞发生-原子荧光光谱法分析。所选择的仪器工作条件为:（1）光电倍增管负高压230V;（2）主阴极峰值电流25mA,辅助阴极峰值电流0;（3）2g·L^-1氢氧化钾-0.05g·L^-1硼氢化钾混合液为还原剂;（4）载气（氩气）流量800mL·min^-1;（5）原子化器温度200℃;（6）原子化器高度7mm。结果表明:汞的质量在12.00ng以内与荧光强度呈线性关系,方法的检出限（3s）为0.24ng·g^-1。方法用于测定地球化学国家一级标准物质中的痕量汞,测定值与认定值相符,测定值的相对标准偏差（n=12）小于8.0%。更多还原

【Abstract】 The sample（0.200 0 g） was added into 5 mL of a mixture of hydrochloric acid and nitric acid（9+1）,and the solution was heated in boiling water for 2 h.After cooling,5 mL of a solution containing 75 g·L^-1 thiourea and 75 g·L^-1 ascorbic acid was added and mixed well.Then the volume of the solution was made up to25 mL with 3 mol·L^-1 hydrochloric acid solution containing 5 g·L^-1 tartrate.After shaking,the sample solution was used for cold atomic mercury generation-atomic fluorescence spectrometry analysis.Working conditions of the instrument were chosen as follows:（1） negative high voltage of photomultiplier tube was 230 V;（2） peak currents of main cathode and auxiliary cathode were 25 mA,0,respectively;（3）a mixed solution containing 2 g·L^-1 KOH and 0.05 g·L^-1 KBH₄ was used as reducing agent;（4）flow-rate of carrier gas（argon） was 800 mL·min^-1;（5）temperature of atomizer was 200℃;（6） height of atomizer was 7 mm.It was showed that,linear relationship was found between fluorescence intensity and mass of mercury within 12.00 ng,with detection limit（3 s） of 0.24 ng·g^-1.The proposed method was applied to determination of mercury in GBWs for geochemistry,giving results in consistency with certified values and RSDs（n=12） less than 8.0%.更多还原