Characterization of a carbon paste electrode containing organically modified nanostructure silica; Application in voltammetric ferricyanide detection

A carbon paste electrode modified with aminopropyle-grafted mesoporous silica (APS) material was evaluated as an electrochemical sensor for ferricyanide species in aqueous medium. This solid material was characterized by Fourier transform infrared (FTIR) spectroscopy. Electrochemical detection was achieved after protonation of N-bearing groups on APS located at the electrode surface giving positive charge and accumulation of ferricyanide anion at open circuit. The influence of various experimental parameters (i. e. pH of the pretreatment, detection and accumulation media, carbon paste composition, accumulation time) on the sensor response was investigated. The linear analytical curves was obtained in the range of 2×10-7-10-5 M for ferricyanide using DPV method. The detection limit (2σ) was determined 8×10-8 M. This new sensor was applied to ferricyanide analysis in electroplating waste.