Preconcentration system for cadmium and lead determination in environmental samples using polyurethane foam/Me-BTANC
Ednilton Moreira Gama1, Adriana da Silva Lima, Valfredo Azevedo Lemos
1Universidade Estadual do Sudoeste da Bahia, Núcleo de Química Analítica da Bahia (NQA), Laboratório de Química Analítica (LQA), Campus de Jequié 45200-000, Jequié-BA, Brazil.
Abstract:
In this work, polyurethane foam (PUF) loaded with 2-(6'-methyl-2'-benzothiazolylazo)chromotropic acid (Me-BTANC) was packed in a minicolumn and it was used in an on-line preconcentration system for cadmium and lead determination. Optimum hydrodynamic and chemical conditions for metal sorption were investigated. The effects of several foreign substances on the adsorption of cadmium and lead were also reported. The enrichment factor obtained was 37 (Cd and Pb) for 180 s preconcentration time. The proposed procedures allowed the determination of metals with detection limits (3 sigma) of 0.80 and 3.75 microg L(-1) (0.10 and 0.47 microg g(-1) of solid sample) for cadmium and lead, respectively. The precision of the procedures was also calculated: 3.1 (Cd 10 microg L(-1)) and 4.4% (Pb 100 microg L(-1)). The accuracy of the procedure was checked by analysis of the certified reference materials Spinach Leaves and Fish Tissue. Cadmium and lead contents in environmental samples (black tea, spinach leaves, natural and tap water) were determined by applying the proposed procedure.
