Novel amperometric sensor based on mesoporous silica chemically modified with ensal copper complexes for selective and sensitive dopamine determination

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Disordered mesoporous silica (DMS), prepared by the sol-gel method, was chemically modified with ensal functional groups. Copper complexes were formed on the surface of the resulting material. A homogeneous mixture of the DMS/(ensal)(2)Cu with ultra pure graphite (99.99%) was pressed in disk format in order to fabricate a working electrode that displayed an excellent specific electrocatalytic response to dopamine (DA) oxidation. Under optimized conditions, at -20 mV vs. SCE in 0.04 mol L-1 Britton-Robinson buffer (BRB) solution (pH 7.0) containing 200 mu mol L-1 of H2O2, a linear response range for dopamine from 5 up to 130 mu mol L-1 was obtained with a sensitivity of 21.2 (+/- 0.003) nA L mu mol(-1) cm(-2) and the limit of detection LOD was 0.52 mu mol L-1. The sensors presented stable response during successive determinations. The repeatability, evaluated in terms of relative standard deviation of