Characterization of a carbon paste electrode containing organically modified nanostructure silica: Application to voltammetric detection of ferricyanide

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 such as solution pH in pretreatment step, accumulation and detection conditions, carbon paste composition and accumulation time upon the sensor response were investigated. The differential pulse voltammetry (DPV) method showed the linear dynamic rang of 2 × 10−7–1 × 10−5 M for the ferricyanide concentration. The detection limit (2σ) was determined 8 × 10−8 M. This new sensor was applied to ferricyanide analysis in electroplating waste.