Behaviour of the faujasite zeolite occluded with Ti(IV) and Zr(IV) and its interaction with nickel hexacyanoferrate (III): a comparative study in the voltammetric detection of isoniazid

This study describes titanium and zirconium incorporations into a FAU zeolite and subsequent modification with nickel hexacyanoferrate.The obtained materials (ZTiNiH and ZZrNiH) were characterized by Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), X-ray Dispersive Energy Spectroscopy (EDS), Porosity and Surface Area and Cyclic Voltammetry (CV). The cyclic voltammograms of the modified ZTiNiH and ZZrNiH carbon paste electrodes in the proportions graphite-modifier (20% m/m) indicate sensitivity to isoniazid (IZN). The modified ZTiNiH carbon paste electrode displayed a linear analytical curve response from 4.0× 10^-5 to 7.0× 10^-4 mol L^-1 and a limit of detection of 4.9×10^-5 mol L^-1, while the modified ZZrNiH electrode presented a linear analytical curve response from 1.0×10^-5 a 3.0×10^-4 mol L^-1 and a limit of detection of 2.0×10^-5 mol L^-1. The amperometric sensitivity was 47.59 mA/mol L^-1 and 20.55 mA/mol L^-1 for ZTiNiH and ZZrNiH respectively. After catalytic IZN electro-oxidation, a study concerning the main IZN interferents was performed and its recovery from a synthetic urine sample was assessed. The obtained ZTiNiH and ZZrNiH materials are noteworthy for their good limit of detection and recovery efficiency when applied to real samples, thus comprising potential candidates for the development of electrochemical sensors aiming at IZN detection. (author)