Formaldehyde measurement based on its electrocatalytic oxidation by Ni-TiO2 nanoparticles/chitosan modified carbon paste electrode as an effective method

Abstract

In this work, for the first time, a new and effective bulk modified carbon paste electrode (CPE) was prepared by TiO₂ nanoparticles and chitosan and then Ni²⁺ ions were incorporated to this electrode by immersion of the modified electrode in nickel chloride solution. The values of electron transfer coefficient, charge-transfer rate constant and electrode surface coverage for Ni(II)/Ni(III) redox couple of the TiO₂/chitosan modified carbon paste electrode (Ni-TiO₂/CHIT/CPE) were found to be 0.66, 3.28 Ã 10^-1 s^-1 and 5.14 Ã 10^-8 mol cm^-2, respectively. The prepared Ni-TiO₂/CHIT/CPE material was characterized by scanning electron microscopy and Xâray diffractometry. The electrochemical behaviour of the Ni-TiO₂/CHIT/CPE towards oxidation of formaldehyde was evaluated and proved. The effects of various factors on the efficiency of electrocatalytic oxidation of formaldehyde were optimized. Under the optimized condition, a calibration curve was obtained in the linear dynamic range of 2.80 Ã 10^-4 to 2.50 Ã 10^-2 mol L^-1 with detection limit of 7.14 Ã 10^-5 mol L^-1 (3Ï/slope) for formaldehyde determination. Also, the method was successfully applied for formaldehyde measurement in the real sample.