Determination of Atomoxetine Hydrochloride in Biological Fluids Using Potentiometric Carbon Paste Electrode Modified by TiO2 Nanoparticles

Abstract

Endeavors to improve the limit of detection for atomoxetine-selective electrode were documented. Simple potentiometric carbon paste electrodes (CPEs) based on atomoxetine-derivatized with tetraphenylborate (ATM-TPB) or phosphotungstic acid (ATM-PTA) as ion-pairs decorated with TiO2 nanoparticles and sodium tetraphenylborate (Na-TPB) as additives were most useful. Parameters affecting the performance of the electrodes were investigated, such as paste composition, type of plasticizers, kind of electroactive materials and interfering species. The electrodes were notable for bringing down the detection limit to 8.0 x 10-7 M and 9.2 x 10-7 M, wide linear ranges 1.1 x 10-6-1.0 x 10-2 M and 1.75×10-6-1.00×10-2 M, slope 58.7±0.5 mV/decade and 67.2±0.8 mV/decade, respectively. Importantly, the potential reading became more stable and rapidly attained in the presence of additives. The selectivity for the drug over other species such as inorganic and organic cations, as well as different excipients that are likely incorporated in pharmaceutical preparations was high making their effect negligible on the response of the electrodes. The sensors, as indicator electrodes, were successfully applied for determination of the drug in pharmaceutical preparation, urine and serum with good accuracy, excellent recovery and efficiency.