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

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 =  + 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.

Keywords: low-cost device; H₂O₂ detection; paper-based device; electrochemical device; modified graphite-based electrode

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                                            E-mail: mnkaumal@sci.cmb.ac.lk