Desenvolvimento e aplicação de métodos para a determinação de Bromo e Iodo por ICP-MS em saliva de origem humana

Abstract

In this work, sample preparation methods were evaluated for the further determination of bromine and iodine by inductively coupled plasma mass spectrometry (ICP-MS) in saliva. In this sense, methods such as microwave- induced combustion (MIC), microwave assisted dissolution and direct analysis of saliva (after sample centrifugation) were evaluated. Thus, types and concentrations of solutions were evaluated in order to select the most appropriate solution to the evaluated methods. For MIC, 0.2 mL of saliva and 300 mg of microcrystalline cellulose were used, and the analytes were absorbed in 50 mmol L-1 NH4OH solution. The limits of detection (LOD) were 0.08 and 0.03 μg mL-1 for bromine and iodine, respectively. In the microwave assisted dissolution, 2 mL of saliva were dissolved in a solution of 25 mmol L-1 NH4OH, LODs lower than the MIC were obtained in the order of 0.005 μg mL-1 for bromine and 0.001 μg mL-1 for iodine. When the samples were centrifuged, it was not possible to obtain quantitative recoveries for iodine. The methods based on the MIC and microwave assisted dissolution were suitable for the determination of both analytes, presenting adequate accuracy, precision and low LDs.