Procedure 17 Preparation of Prussian blue-modified screen-printed electrodes via a chemical deposition for mass production of stable hydrogen peroxide sensors

Publisher Summary This chapter presents a procedure to obtain a stable and easy to produce Prussian blue modified screen-printed electrode for the amperometric detection of hydrogen peroxide. The procedure presented in this protocol for PB deposition is based on the spontaneous reaction between the two precursors of PB and does not require any electrochemical steps, which have typically been employed in the most common procedures for PB deposition. Two procedures usually adopted for PB deposition. In the case of the electrochemical procedure, the electrode is first placed in a cell containing FeCl 3 and K 3 Fe(CN) 6 and after deoxygenation (10 min) a constant potential of +0.4V for 60 s is applied. After this, the electrode is washed and activated with a constant potential and a CV experiment and then dried for 1 h at 100°C. In the case of the chemical deposition, a drop of FeCl 3 is placed on the working electrode and followed by the injection of a drop of K 3 Fe(CN) 6 . After 10min the electrode is washed and dried at 100˚C for 1h. The chemical deposition of PB leads to an effective modification of the electrode surface, which then shows positive features as to hydrogen peroxide detection with an effective rate constant very similar to that measured for the peroxidase enzyme.