巯基棉富集-氢化物发生原子荧光法测定地质样品的总硒含量

DETERMINATION OF TOTAL SELENIUM IN GEOLOGICAL SAMPLES BY HG-AFS AFTER ENRICHMENT WITH THIOL COTTON FIBER

地球化学标准参考物质和不同的地质样品均分别采用消解方式A（硝酸、高氯酸混合液）、B（硝酸、高氯酸、氢氟酸混合液）体系消解，样品预先用琉基棉（TCF）吸附装置分离富集，通过氢化物发生原子荧光光谱法（HG-AFS）测试。实验优化了Se（Ⅵ）到Se（Ⅳ）的还原效果、仪器条件、TCF吸附条件。两种消解体系所测得结果有很好的一致性，相关系数为0．9986。对于含硒量为0．04μg／g样品，方法的相对标准偏差为10．2％。A、B体系标准加入法的回收率分别为96％～106％和99％～104％。

Standard reference material and different geological samples were dissolved by system A （the mixture of nitric, perehlorie acids） and system B （the mixture of nitric, perchloric and hydrofluoric acids）, and total Se in all the samples was measured by hydride generation atomic fluorescence spectrometry （HG-AFS） after enrichment with thiol cotton fiber （TCF）. The agreement is very good （within error） for most of the samples, particularly for those having recommended values with two different digestion methods. The Se concentrations found in our study by the two methods are identical, the correlation coefficient is 0.9986 ; the relative standard deviation （RSD） for the determination of 0.04 μg/g Se is 10. 2% ; and the recovery of systems A and B are 96%--106% and 99%--104%, respectively.