CARBON PASTE ELECTRODE MODIFIED WITH ORGANOFUNCTIONALIZED MESOPOROUS SILICA FOR ELECTROCHEMICAL DETECTION AND DETERMINATION OF COPPER(II) USING CYCLIC VOLTAMMETRY AND ANODIC STRIPPING VOLTAMMETRY

A carbon paste electrode modified with hexagonal mesoporous silica functionalized with acetyl-acetone (AcAcNH(2)-HMS) was prepared and used as a sensor for copper(II). The advantage of mesoporous HMS silica is that it is not necessary a pre-treatment before modifying the surface, compared to silica gel typically used in these methods. In order to characterize the electrochemical behaviour of carbon paste - functionalized HMS silica mixture, to detect and to determine copper(II) in aqueous medium, cyclic voltammetry and anodic stripping voltammetry were used. The best results were obtained under the following conditions: 100 mV.s(-1) scan rate, - 0.65 V vs. SCE deposition potential, 210 s accumulation time in Britton-Robinson buffer (pH 2.56). Linear response to copper(II) was found between 0.4.10(-6) and 8.10(-5) mol.L(-1), with a detection limit of 3.02.10(-7) mol.L(-1).