Voltammetric determination of an antipsychotic agent trifluoperazine at a boron-doped diamond electrode in human urine

Abstract

A simple and efficient procedure is described for electrochemical determination of trifluoperazine (TFP), a prominent compound in a large group of phenothiazine derivatives with potent physiological activity. This method is based on the electrochemical oxidation of TFP in Britton–Robinson buffer solution in pH 6 at a boron-doped diamond electrode. Cyclic voltammetry provided a four well defined oxidation peaks at +0.65, +0.83, +1.06 and +1.35 V (vs. Ag/AgCl/3 M KCl electrode). Differential pulse voltammetry was applied as a very sensitive analytical technique for the determination of micromolar amounts of TFP. Two oxidation peaks on higher potentials were chosen for quantification of TFP. Under optimized conditions, the analytical curves obtained were linear in the TFP concentration range of 1.0 to 37.0 μmol L⁻¹, with a detection limit of 0.7 and 0.6 μmol L⁻¹, respectively. The effect of interfering agents (common urinary compounds) appeared to be negligible confirming the favourable selectivity of the method. The proposed method was analytically applied by determination of trifluoperazine content in model human urine samples with good accuracy (recoveries varied from 97% to 104%). The developed approach could be beneficial in analysis of TFP in biological samples using a boron-doped diamond electrode as an up-to-date electrochemical sensor and could represent an inexpensive analytical alternative to separation methods.