ICP-AES Determination of Silicon in Magnesium and Magnesium Alloys

Samples of magnesium and its alloys were completely dissolved by addition of dil.HNO3 and small amount of HF,and the sample solution obtained was used for determination of silicon by ICP-AES or molybdenum blue-spectrophotometric method.Conditions for ICP-AES determination of silicon were studied and optimized.To avoid the interferences of co-existing ions,spectral lines of SiⅠ 251.611 nm and SiⅠ 212.412 nm were chosen as the analytical lines.The interference of matrix effect due to magnesium was eliminated by addition of appropriate amounts of magnesium to each portion of standard silicon solutions in preparation of calibration curve.Linear relationships between values of the spectral emission intensity and mass concentration of silicon were kept in the range within 40.0 mg·L-1 for using either of the 2 analytical spectral lines,and the detection limits (3S/N) of 6.2 μg·L-1 and 15 μg·L-1 were obtained when determined with the 2 analytical spectral lines respectively.Three standard samples of magnesion alloys were analyzed by the proposed method,giving results in consistency with the standard values.