Low Cost Paper-based Electrochemical Sensing Platform for the Determination of Hydrogen Peroxide

Abstract

A rapid, precise, low cost, selective and sensitive paper-based electrochemical device for the determination of H2O2 in milk is described here. Commercially available varnish and a simple hand drawing method were used to develop the hydrophobic pattern to generate a hydrophilic detection zone on the filter paper. The electrode system was fabricated on the detection zone in order to detect H2O2 electrochemically. A commercially available graphite pencil and conductive silver ink were used to fabricate the counter electrode and pseudo-reference electrode, respectively. A paste of Prussian blue (PB) modified graphite, unmodified graphite and phenol-formaldehyde polymer were used to fabricate a PB modified graphite working electrode on paper. This modified electrode showed electrocatalytic activity towards the reduction of H2O2 and it was successfully used for the chronoamperometric detection of H2O2 at 0 V vs Ag reference electrode in 0.1 mol l-1 phosphate buffer, buffered at pH 6.0 in 0.1 mol l-1 KCl. Under optimum conditions, the calibration curve for the H2O2 determination was linear from 5 to 50 mmol l-1 with a detection limit (LoD = x ̅ + 3SD) of 4.0 mmol l-1. In addition, the PB modified graphite electrode showed selectivity for H2O2 detection in the presence of ascorbic acid, sucrose and citric acid.