Square wave voltammetric determination of dexamethasone on a multiwalled carbon nanotube modified pencil electrode

Abstract

The electrochemical behavior of dexamethasone, a steroid hormone, was studied on a multiwalled carbon nanotube (MWCNTs) modified pencil electrode (PE) by square wave voltammety and electrochemical impedance spectroscopy (EIS). Dexamethasone showed one oxidation peak potential around +0.80 V on the surface of the modified electrode. Under optimized conditions, the oxidation peak current depended on the dexamethasone concentration and was linear in the range of 0.15-100 μmol L-1 dexamethasone with a detection limit of 0.09 μmol L-1 dexamethasone. The effects of potential interfering substances on the determination of dexamethasone were investigated to find that the proposed sensor is a sensitive and fast tool for the determination of dexamethasone in both pharmaceutical and human urine samples without any pretreatment. © 2011 Sociedade Brasileira de Química.