Determinação de metais em peixes por MIP OES com sistema MSIS

Abstract

Considered an excellent source of protein, vitamins and fatty acids, fish are increasingly inserted into a balanced diet because they are beneficial to health. Within the aquatic food chain, the fish are at the superior level and they can accumulate potentially toxic metals, causing health risks to the consumer. In the present work, five fish samples were analyzed (Bagre, Tainha, Traíra Pintado e Corvina) to determine the concentrations of Al, Cd, Cu, Hg, Mg, Sb and Zn using the MIP OES technique with multimode sample introduction system (MSIS). Samples were prepared using the acid decomposition with the reflux system. In order to obtain the best analysis conditions using the MSIS system, some parameters such as the concentration of HCl and the reducing agent NaBH4 were optimized. The best conditions established were HCl 2% (v/v); NaBH4 0.5% (m/v) stabilized with 0.5% (m/v) NaOH. The accuracy was evaluated through analyzes of certified reference materials and analyte addition tests. The recoveries obtained in both methods were in the range of 80 to 115.72%, indicating good accuracy. Also, a comparison of the MSIS system with the conventional nebulization system was performed and an improvement in the sensitivity of some analytes was observed. After analysis of the samples, concentrations of 6.43 to 24.7 mg kg-1 for Al, 168.2 to 211.25 mg kg-1 for Mg and 23.1 mg kg-1 for Zn were found and are within the limits allowed by the legislation for fish. For the other elements, the concentrations were below the limits of detection and quantification.