冷原子汞发生-原子荧光光谱法测定地球化学样品中痕量汞  

Determination of Trace Mercury in Geochemical Samples by Cold Atomic Mercury Generation-Atomic Fluorescence Spectrometry

作　　者：陆迁树 段文 李发刚[1] 张先昌 杨晓光[1] LU Qianshu;DUAN Wen;LI Fagang;ZHANG Xianchang;YANG Xiaoguang(Golden 10 Unit of Chinese People s Armed Police Force , Kunming 650100, China)

机构地区：[1]中国人民武装警察部队黄金第十支队,昆明650100

出　　处：《理化检验（化学分册）》2019年第3期338-342,共5页Physical Testing and Chemical Analysis(Part B:Chemical Analysis)

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%。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 to 25 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 (3s) 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%.

关 键 词：冷原子汞发生-原子荧光光谱法 痕量汞 地球化学样品 

分 类 号：O657.3[理学—分析化学]