Efficient benchtop acid digestion of organic-rich sediments for ICP-MS analyses: testing analytical procedures on NIST 2702 standard reference material

Abstract

Trace element abundances in organic-rich sediments are widely used in various fields of the geosciences, yet few contributions discuss the effectiveness of low-cost benchtop acid digestion techniques for such samples. Here, we tested three different sample preparation methods (acid digestion in closed and open vessels, and fusion) on twelve powder aliquots of organic-rich sediment, standard reference material NIST 2702. Comparison of newly obtained ICP-MS and LA-ICP-MS results with their respective certificate values, facilitates the assessment of digestion efficiency and the effects of vessel size, acid mixture, and other parameters on the recoveries of 29 trace elements. Our results show that benchtop digestion of organic-rich sediment in closed 7 mL PFA vessels using HF+HNO3+HClO4 mixture is more efficient compared with open vessel digestion treated with the same acid mixture (± HCl), with closed or open vessel digestions without HClO4, and with LA-ICP-MS measurements on fused glass discs.