Determinação voltamétrica de triclocarban e carbendazim em produtos de higiene pessoal e água potável

Abstract

Triclocarban (TCC) is a bactericide and fungicide widely used in personal care products, while carbendazim (MBC) is a fungicide widely used in cereal crops and a variety of fruits and vegetables, both are considered environmental contaminants. In this paper, propose the study of oxidation and determination of TCC using glassy carbon electrode (ECV) and the use of a carbon paste electrode modified with carbon nanotubes functionalized multi walled (EPC-NTCPMF) to determine MBC. Electrochemical detection of TCC and MBC was studied using different voltammetric techniques on a wide range of pH and the determination was performed on samples of soaps, only the TCC and drinking water at low concentrations, for both contaminants. For TCC, various oxidation processes were observed, however the peak P1 had greater sensitivity and selectivity in acetate buffer, pH 5.4 and was therefore used for the development of voltammetric methods, direct VOQ and adsorptive stripping voltammetry. For adsorptive stripping voltammetry, the linear response range was from 1.8 to 21 × 10-9 mol L-1 with a detection limit (LD) of 3.2 × 10-10 mol L-1, 1,000 times smaller than the LD obtained by direct VOQ. The method of adsorptive stripping voltammetry showed satisfactory levels of repeatability, 4.1% and reproducibility, 5.4% and was applied to determine TCC in soaps samples and an average recovery of 95.3% and drinking water with an average recovery apparent 95.4%. The MBC peaked main oxidation, almost reversible; the better sensitivity was achieved in H2SO4, pH 1.0 on the EPC-NTCPMF using VOQ. The linear response range is between 3 and 150 × 10-10 mol L-1 to LD 1.1 × 10-11 mol L-1. The method developed showed acceptable levels of repeatability, 4.6% and reproducibility, 6.2% and was applied for MBC determination in drinking water samples obtained average apparent recovery of 95.6%. The results obtained in the development of methods for determination of TCC and MBC showed excellent applicability for the studied samples, in addition to having advantages such as low cost instrumentation, analytical fast response, high sensitivity and selectivity.