AFS Determination of As and Hg in the Mineral Feed (Calcium Orthophosphate)

The sample of mineral feed,calcium orthophosphate,was dissolved with HNO3 solution,and the contents of As and Hg in the sample solution were determined by AFS.Influential factors,including working conditions of instrument,kinds of reagents for dissolving sample,concentration of HCl medium,amount of pre-reductant required,concentration of potassium borohydride,and interferences of coexisting ions,were studied and optimized.Linear relationships between the values of fluorescence intensity and mass concentration of As and Hg found were in the ranges within 100.0 and 5.0 μg·L-1,with detection limits (3s) of 0.18 and 0.06 μg·L-1,respectively.The values of RSD′s (n=11) found were all less than 8.0%.The proposed method was applied to the analysis of 3 samples of calcium orthophosphate,and test for recovery was made by standard addition method,giving values of recovery in ranges of 91.7%-103.0% (As) and 91.0%-93.7% (Hg).