DESENVOLVIMENTO DE METODOLOGIA EM SISTEMA EM FLUXO PARA DETERMINAÇÃO DE CD USANDO ERVA MATE E CHÁ PRETO COMO ADSORVENTE E ESPECTROMETRIA DE ABSORÇÃO ATÔMICA EM CHAMA

Abstract

In this study new methods for determination of cadmium in certified biological samples using mate (llex paraguariensis) and black tea (Camellia sinensis, L.) as biosorbents in an on-line preconcentration system coupled to flame atomic absorption spectrometry was developed. Flow and chemical variables of the proposed system were optimized through multivariate designs. Sample pH, buffer concentration, sample flow rate and biosorbents mass were the selected variables. The limit of detection for cadmium was 0.98 μg L-1 with a precision below 3.6% (35 μg L-1, n=6) for mate biosorbent and 0.97 μg L-1 with a precision below 4.4% (35 μg L-1, n=7) for black tea biosorvent. For both biosorbents the analytical curves were linear from 5 to 50 μg L-1, with a correlation coefficient of 0.9995. The developed methods were successfully applied to certified reference materials (pig kidney and human hair).