Static and Hydrodynamic Monitoring of Citalopram Based on its Electro-oxidation Behavior at a Glassy-Carbon Surface

The electrooxidative behavior of citalopram (CTL) in aqueous media was studied by cyclic voltammetry (CV) and square-wave voltammetry (SWV) at a glassy-carbon electrode. The electrochemical behaviour of CTL involves two electrons and two protons in the irreversible and diffusion controlled oxidation of the tertiary amine group. The maximum analytical signal was obtained in a phosphate buffer (pH = 8.2). For analytical purposes, an SWV method and a flow-injection analysis (FIA) system with amperometric detection were developed. The optimised SWV method showed a linear range between 1.10 × 10−5–1.20 × 10−4 mol L−1, with a limit of detection (LOD) of 9.5 × 10−6 mol L−1. Using the FIA method, a linear range between 2.00 × 10−6–9.00 × 10−5 mol L−1 and an LOD of 1.9 × 10−6 mol L−1 were obtained. The validation of both methods revealed good performance characteristics confirming applicability for the quantification of CTL in several pharmaceutical products.