氢化物发生-原子荧光光谱法同时测定地下水中砷和汞

Simultaneous determination of arsenic and mercury in groundwater by hydride generation-atomic fluorescence spectrometry

建立了氢化物发生-原子荧光法同时测定地下水中砷和汞的方法。研究了灯电流、载气流速、原子化器高度、盐酸浓度和硼氢化钾浓度等因素对检测的影响。在仪器最佳工作条件下,砷和汞的质量浓度分别在1.2～100ng/mL和0.022～1.0ng/mL范围时呈现良好的线性关系,相关系数均在0.9994以上;砷和汞的检出限分别为0.21ng/mL和0.0038ng/mL;对不同含量的砷、汞混合溶液进行测定,相对标准偏差分别小于0.78%和1.2%(n=11)。加入硫脲-抗坏血酸混合掩蔽剂,提高了干扰元素的允许量及方法的灵敏度。应用于山东、河南、安徽及长三角地下水样检测,其结果符合地质矿产实验室有关水样测试的质量管理规范要求,回收率在96%～112%之间。

The simultaneous determination method for arsenic and mercury in groundwater by hydride genera- tion-atomic fluorescence spectrometry was established. The effects of lamp current, flow rate of carry gas, height of atomizer, concentrations of hydrochloric acid and potassium borohydride on determination were investigated. Under the optimal working conditions of instrument, arsenic and mercury exhibited good linearity in the mass concentration ranges of 1.2-- 100 ng/mL and 0. 022-- 1.0 ng/mL, respectively. The correlation coefficients were all above 0. 999 4. The detection limits of arsenic and mercury were 0. 21 ng/mL and 0. 0038 ng/mL, and the relative standard deviations （RSD） for determining the mixed solution of arsenic and mercury at different levels were less than 0. 78 % and 1.2%, respectively. Thiourea-ascorbic acid mixed masking agent increased the tolerant amount of interference ions and improved the sensitivity of method. The proposed method was applied to the determination of groundwater samples from Shandong, Henan, Anhui and Yangtze River delta with the recoveries between 96 %and 112%. The determination results could meet the laboratory quality control requirements on water testing of geological and mineral resources.