Characterisation of Prussian blue modified screen-printed electrodes for thiol detection

The electrocatalytic behaviour of Prussian blue towards thiol oxidation was thoroughly investigated. Cyclic voltammetry experiments performed in thiol solution showed the classical shape of a mediated redox system. The current due to thiol-mediated oxidation was then evaluated in batch amperometric mode at +200 mV vs. Ag|AgCl. Many thiocompounds were investigated and their different reactivities were discussed. Thiocholine and cysteamine were found to give the best results in terms of LOD (i.e., 5 × 10−6, 10−6 mol l−1, respectively) and linear range (5 × 10−6–5 × 10−4, 10−6–10−4 mol l−1, respectively). Two applications are also proposed, one involving the measurement of thiocholine as a mean for pesticide detection, and the other being an electrochemical alternative to Ellman’s test for total thiol estimation.