Microwave digestion for elemental analysis of photographic emulsions by inductively coupled plasma mass spectrometry

摘要

Elemental analysis of every solid sample requires dissolution prior to introducing the sample into the instrument chosen for the analysis. Traditional methods of sample preparation, e.g., hot plates, contribute to a large amount of irreproducibility and low sample throughput due to time requirements. The use of microwave irradiation rather than convection and/or conduction heating reduces errors in the sample preparation process and also addresses other problems associated with time of analysis and sample contamination. In this study, a microwave digestion method was developed for the preparation of photographic silver halide emulsions for analysis by Inductively Coupled Plasma Mass Spectrometry (ICP-MS). The development of digestion methods for photographic emulsions has enabled us to test for such elements as iridium and gold. Different combinations of acid mixtures and digestion temperatures and pressures were investigated. Recoveries of iridium and gold have typically ranged from 81 - 101% and 83 - 87%, respectively.