Avaliação de diferentes procedimentos de preparo de amostras para a determinação de Br e I em camarão por ICP-MS

Abstract

Samples of shrimp were digested by different sample preparation procedures for further Br and I determination by inductively coupled plasma mass spectrometry (ICP-MS). Procedures as alkaline extraction with heating in a water bath, or assisted by microwave radiation, and microwave induced combustion (MIC) were evaluated. Different solutions and concentrations were studied as extraction medium or absorbing solution for the analites. Taking into account the sample preparation procedures evaluated, better recoveries for Br and I were obtained by MIC using 50 mmol l-1 NH4OH as absorbing solution. Accuracy was evaluated for Br and I using certified reference material (CRM, NIST RM 8414) as well as using spike recoveries. Then, the recoveries and the agreement with the certified values were better than 99%, for both analites. It is important to point out that using MIC lowest values for the blanks were obtained and the limits of detection (LODs) were better, in comparison with the others procedures, for Br (0.12 μg g-1) and I (0.03 μg g-1). Therefore, MIC was suitable for shrimp digestion for subsequently Br and I determination by ICP-MS. In addition, with this procedure was possible to observe that Br (182.43 ± 4.23 μg g-1) and I (11.31 ± 0.95 μg g-1) concentration were higher in shrimp with shell.