Desenvolvimento e validação de métodos voltamétricos sequenciais para a determinação de elementos em matrizes complexas

Abstract

Toxic elements are in continuous accumulation in the environment mainly due to anthropogenic activities. In this work, a voltammetric method of sequential analysis for application in matrices of complex characteristics was developed. Using an organic mixture complexing, SVRS (alizarin violet) DMG (dimethylglyoxime), 8-hydroxyquinoline (oxine), CA (chloranilic acid) and DTPA (diethylenetriaminepentaacetic acid) 13 elements could be determined at two different methods. According to the formation constants with their respective ligands, in method 1, step were determined Al3+, Fe3+, Mo6+ SVRS in the presence of AdSV (Adsorptive Stripping Voltammetry). In step 2 were determined Zn2+, Cd2+, Pb2+ and Cu2+ by ASV. In step 3, were determined Ni2+ and Co2+ in the presence of DMG and oxine. In method 2, V5+ and U6+ were determined by AdSV in the presence of CA (chloranilic acid), Cr(total) was analyzed in sequence by the presence of DTPA by AdSV and finally Tl+ was determined by ASV. The data for the figures of merit showed that the proposed method is suitable for samples of complex matrices studied (certified materials and commercial plant compounds). High concentrations for some elements were found in commercial samples. It indicates that the species translocates through the environment in which they are insert, being susceptible to contact with humans.