海藻中总砷及无机砷含量的测定

Determination of Total Arsenic and Inorganic Arsenic in Marine Algae

采用湿法消解和盐酸浸提法处理样品,氢化物-原子荧光光谱法测定各海藻中总砷和不同价态无机砷的含量。通过正交试验优化样品测定条件。在优化实验条件下,测得总砷检出限为0.05799μg/L,无机砷检出限为0.03351μg/L,三价无机砷检出限为0.05286μg/L;线性相关系数均在0.9994以上;总砷精密度(RSD)为1.33%(n=5),无机砷RSD为2.94%(n=5);总砷的平均加标回收率为102.95%,无机砷为103.40%。对11种海藻样品进行测定,总砷含量在5.15～118.72μg/g范围内;无机砷含量在1.05～89.19μg/g范围内;三价无机砷含量在0.31～27.11μg/g范围内。按照GB/T2762—2005和GB/T19643—2005限量指标中对无机砷的规定,本实验11种样品中无机砷含量除紫晶藻外均超出标准限量。

The samples were pretreated by wet nitration and HCl extraction,and the contents of As in marine algae were determined by HG-AFS.The analytical conditions were optimized by orthogonal designing.Under optimum conditions,the detection limit of total arsenic,inorganic arsenic,trivalent arsenic were 0.05799 μg/L,0.03351 μg/L and 0.05286 μg/L, respectively. The correlative coefficient of linear regression equation was over 0.9994 and the precisions of total arsenic and inorganic arsenic were 1.33% and 2.94% （RSD, n=5）, respectively . The average recoveries were 102.95% and 103.40% （n=5）. The contents of total arsenic and inorganic arsenic in 11 kinds of marine algae samples varied within the range of 5.15 to 118.72 μg/g and 1.05 to 89.19 μg/g. Trivalent arsenic ranged from 0.31 to 27.11μg/g. The contents of inorganic arsenic in the 11 kinds of marine algae samples were beyond GB/T 2762—2005 and GB/T 19643—2005 standard except for amethyst algae.