Study on the preparation of CdTe nanocrystals on the surface of mesoporous silica and evaluation as modifier of carbon paste electrodes

Abstract

Here CdTe nanocrystals were grown onto mesoporous silicas. The influence of the surface areas, volumes and pore diameters of the silica matrices on the spectroscopic properties of CdTe was evaluated. Emission properties of the CdTe were found to depend on the textural properties of silicas. Electrochemical characterization of different electrodes (unmodified carbon paste, and carbon paste modified with the mesoporous silica and with CdTe anchored onto mesoporous silica) evidenced that the presence of CdTe nanocrystals lead to a significant increase of the anodic peak referring to Cu2+ detection. The electrode with optimal characteristics responded to Cu2+ in the linear range from 5.0 × 10−8 to 2.3 × 10−6 mol L−1 and the calculated limit of detection was 6.4 × 10−8 mol L−1. The method developed here proved to be efficient for monitoring Cu2+ in sugar cane spirit (cachaca), with quantitative results comparable to those obtained from Flame Atomic Absorbtion Spectroscopy.