Abstract: A novel method was developed to determine trace sulfur and sodium in pseudo-boehmite commercial products by ICP-AES based on microwave digestion. Then the conditions of microwave digestion and interelement interference were investigated to optimize the microwave digestion procedure and accuracy of analysis. Finally, the standard curve for analyzing the content of sodium and sulfur was established. In the method, 0.1 g pseudo-boehmite was completely digested with 10 mL hydrochloric at the temperature of 185 ℃ in 50 min. The linear range of the standard curve for analyzing the content of sodium in solution by ICP-AES was 0.07-15.00 μg/g with a linear correlation coefficient of 1.000 00; relative standard deviation was 1.1%, and the recovery of the method was between 100.0% and 101.0%. The linear range of the standard curve for analyzing the content of sulfur in solution by ICP-AES was 0.10-35.00 μg/g with a linear correlation coefficient of 0.999 99; relative standard deviation was 1.1%, and the recovery of the method was between 95.0% and 100.0%. The method is suitable for the analysis of contents of sulfur and sodium in pseudo-boehmite commercial products with sodium of 35-7 500 μg/g and sulfur of 50-17 500 μg/g.

Key words: microwave digestion, ICP-AES, pseudo-boehmite, impurity