A Rapid Acid Digestion Technique for the Simultaneous Determination of Bromine and Iodine in Fifty-Three Chinese Soils and Sediments by ICP-MS

Bromine and iodine are important tracers for geochemical and environmental studies. In this study, a rapid acid digestion (HNO3+HF) with ammonia dilution for the simultaneous determination of bromine and iodine in soils and sediments using ICP-MS was developed. The recoveries of Br and I were controlled by the synergic effect of temperature and time. It took only 15min at 140 degrees C for the complete recovery of Br and I in sediment (GSD-2) and soil (GSS-24) reference materials, which is a process that needs 2-6h at 90 degrees C. A serious loss of Br and I was found at a higher digestion temperature of 190 degrees C. A 5% v/v NH4OH dilution effectively eliminated the memory effects and stabilised the signals of Br and I. Moreover, ammonia dilution also avoided the corrosiveness of HF on the sample introduction system and torch of ICP-MS. Tellurium is a more suitable internal standard element than In in the ammonia medium. To avoid the adsorption of residues of dissolution on Te, addition of Te should be carried out after centrifuging the solution. The developed method was successfully applied to determine Br and I in fifty-three Chinese soil and sediment reference materials. This simple method shows great potential for the rapid determination of Br and I in large batches of geological and environmental samples commonly analysed for mineral exploration and environmental geochemistry studies.