Voltammetric determination of hydroxylamine at the surface of a quinizarine/TiO2 nanoparticles-modified carbon paste electrode

A carbon-paste electrode (CPE) was chemically modified with TiO2 nanoparticles and quinizarine (QZ). This was used as an electrochemical sensor for the determination of minor amounts of hydroxylamine (HX). The modified electrode showed very efficient electrocatalytic activity for the anodic oxidation of hydroxylamine, owing to a substantial decrease in anodic overpotentials. Under optimal conditions, the linear range span of HX concentration was 1.0 mu M to 400.0 mu M and the detection limit was 0.173 mu M at a signal-to-noise ratio of 3, using differential pulse voltammetry (DPV). The diffusion coefficient and kinetic parameters (e.g., electron transfer coefficient for HX) were also determined using electrochemical approaches. The sensor demonstrated good stability and reproducibility. To evaluate the applicability of the proposed method to real samples, the modified CPE was applied to the determination of HX in water samples.