Ferrocenedicarboxylic Acid Modified Carbon Paste Electrode: A Sensor for Electrocatalytic Determination of Hydrochlorothiazide

The electrocatalytic oxidation of hydrochlorothiazide has been studied by ferrocenedicarboxylic acid modified carbon paste electrode. Cyclic voltammetry and chronoamperometry were used to investigate the suitability of ferrocenedicarboxylic acid as a mediator for the electrocatalytic oxidation of hydrochlorothiazide in aqueous solution. The oxidation of hydrochlorothiazide occurs at a potential about 300 mV less positive than with the unmodified carbon paste electrode at pH 9.0. The catalytic reaction rate constant, k(h) was calculated (3.38 x 10(2) cm(3) mol(-1) s(-1)) using chronoamperometry. Under the optimized conditions, the electrocatalytic oxidation peak current of hydrochlorothiazide showed two linear dynamic ranges with a detection limit of 0.037 mu mol L-1 hydrochlorothiazide. The linear calibration ranges were between 0.08-5.8 mu mol L-1 and 5.8-500.0 mu mol L-1 hydrochlorothiazide using square wave voltammetric method. Finally, the proposed method was also examined as a selective, simple and precise electrochemical sensor for the determination of hydrochlorothiazide in real samples such as drug and urine.