Multiwalled Carbon Nanotubes Modified Electrode as a Sensor for Adsorptive Stripping Voltammetric Determination of Hydrochlorothiazide

The study of electrochemical behavior and determination of hydrochlorothiazide, a thiazide diuretic and antihypertensive drug, on multiwalled carbon nanotubes (MCNTs) modified glassy carbon electrode (GCE) is described by adsorptive stripping voltammetry in open circuit potential. The cyclic voltammetric results indicate that MCNTs remarkably enhance the oxidation of hydrochlorothiazide in wide pH range of 2.0-9.5, which is leading to considerable improvement of anodic peak current for hydrochlorothiazide, and allow the development of a highly sensitive voltammetric sensor for determination of hydrochlorothiazide in pharmaceutical and urine samples. Electrochemical studies by alpha-Fe₂O₃ nanoparticles modified carbon paste electrode show these oxides have no electrocatalytic effect for hydrochlorothiazide oxidation and support iron oxide impurities in the MCNTs are not active sites in sensing of hydrochlorothiazide. Under optimized conditions, the oxidation peak have two linear dynamic range of 2.0-20.0 nM and 0.2-100.0 muM with experimental detection limit of 0.8 nM and a precision of < 4% (RSD for 8 analysis).