Abstract

The direct electrochemistry of Hydroxylamine oxidase (HAO) / zinc oxide (Zno) nanoparticles (Nps) /carbon paste electrode (CPE) was studied for design a new biosensor for detect Nitrite (NO2-) and hydroxylamine (NH2OH). A conventional three electrode cell was employed throughout the experiments, with bare or Zno nanoparticles/ HAO modified carbon paste electrode (4.0 mm diameter) as a working electrode, an Ag/AgCl as a reference electrode and a platinum electrode as a counter electrode; all electrochemical study done by voltammetric method (here cyclic voltammetry (CV) ). Samples were measured and recorded using a TU-1901 double-beam UV-visible (UV-VIS) spectrophotometer and phase characterization was performed by means of X-ray diffraction (XRD) and also the morphologies and particle sizes of the samples were characterized by scanning electron microscopy (SEM). The results showed that the redox process was an adsorption-controlled and the immobilized Hydroxylamine oxidase was stable and could detect NO2- concentration in solution in the range of 5 to 43 mu M; also mentioned biosensor could detect hydroxylamine at surface of modified CPE with Zno (Nps).