ICP-AES Determination of 6 Elements in Bentonite with Microwave Digestion

The bentonite sample was digested with nitric acid,hydrochloric acid and hydrofluoric acid in super microwave digester. After digestion, perchloric acid was added to remove organic matter and carbon by heating. ICP-AES was applied to the determination of 6 elements, i.e. Ca, Mg, P, Mn, Fe and Ti in the sample solution. Linear relationships between values of emission intensity and mass concentration of the 6 elements were kept in definite ranges. Detection limits (3s) of the method ranged from 0.001 to 0.009 mg·L^-1. The proposed method was applied to the analysis of bentonite sample, giving RSDs (n=11) of determined values in the range of 0.74%-2.7%. Test for recovery was performed by standard addition method, giving values of recovery in the range of 96.0%-102%. Results given by the method were in consistency with the values obtained by XRFS.