热分解汞齐化原子吸收法测定煤中高含量汞的方法分析

由于煤中汞含量的准确测定对于控制汞对环境造成的污染有着重要的作用,尝试采用热分解汞齐化原子吸收法以准确测定高汞煤样中的汞含量。结合直接测汞仪的测试流程简要介绍了热分解汞齐化原子吸收法测汞的测试原理,并对减少空白值和降低仪器记忆效应的方法进行分析以提高样品分析的准确度。考察了固定剂L-半胱氨酸溶液的浓度对汞标准溶液测定结果的影响,得出L-半胱氨酸的最佳配制浓度为100 mg/L。采用热分解汞齐化原子吸收法和冷原子吸收法同时测定11个高含量汞的煤样,通过t检验对比分析2种测试方法的测定结果,计算其差值的平均值为0.012μg/g,差值的95%置信区间为-0.048μg/g^0.072μg/g,t值为1.474,小于临界值2.228,表明2种方法测定结果的准确度无显著性差异,即热分解汞齐化原子吸收法测定煤中高含量汞样品结果准确、稳定可靠;F检验结果表明2种方法测定结果有显著性差异,热分解汞齐化原子吸收法测定高含量汞样品时其结果精密度优于冷原子吸收法。

Determination of high content mercury in coal by thermal decomposition and homogenization atomic absorption spectrometry

Because that the accuracy determination of mercury in coal has important effect on controlling of mercury pollution,the thermal decomposition and homogenization atomic absorption spectrometry was used in this paper to determine the mercury content for high mercury coal sample.It was introduced the testing principle of thermal decomposition mercury homogenization atomic absorption method combined with the testing process of direct mercury analyzer.Then the methods of reducing blank value and memory effect of the instrument were analyzed to improve the accuracy of sample analysis.It was studied the effect of the concentration of L-cysteine solution on the results of mercury standard solution.The optimum concentration of L-cysteine fixing agent was 100 mg/L.11 high mercury coal samples were tested by both thermal decomposition and homogenization atomic absorption spectrometry and cold atomic absorption method,through t test,the determination results of these two methods were compared,the average value of the difference between the two methods was 0.012μg/g,the 95%confidence interval of the difference was-0.048μg/g^0.072μg/g,the t value was 1.474,which was less than the critical value of 2.228.The results show that there is no significant difference in accuracy between the two methods,thermal decomposition and homogenization atomic absorption spectrometry is accurate,stable and reliable in the determination of high mercury in coal.The results of F test show that there are significant differences between the two methods.The precision of thermal decomposition and homogenization atomic absorption spectrometry is better than that of cold atomic absorption method.