Benzoylferrocene-modified carbon nanotubes paste electrode as a voltammetric sensor for determination of hydrochlorothiazide in pharmaceutical and biological samples

The electrooxidation of hydrochlorothiazide (HCT) at the surface of a benzoylferrocene modified multi-walled carbon nanotube paste electrode was studied using electrochemical approaches. Under the optimized conditions (pH 7.0), the square wave voltammetric peak current of HCT increased linearly with HCT concentration in the ranges of 6.0 x 10(-7) to 3.0 x 10(-4) M. The detection limit was 9.0 x 10(-8) M HCT. The diffusion coefficient (D = 1.75 x 10(-5) cm(2)/s) and electron transfer coefficient (alpha = 0.45) for HCT oxidation were also determined. The proposed sensor was successfully applied for the determination of HCT in human urine and tablet samples.