Novel electrochemical microsensor for hydrogen peroxide based on iron-ruthenium hexacyanoferrate modified carbon fiber electrode

Novel electrochemical microsensor based on mixed iron-ruthenium hexacyanoferrate (FeRuHCF) modified carbon fiber microelectrode (CFME) is presented for voltammetric and amperometric measurement of hydrogen peroxide at physiological pH. The FeRuHCF coating was electrochemically deposited using a one step procedure onto the substrate carbon fiber microelectrode by cycling the potential between 0.0 and + 1.0 V (vs. Ag/AgCl) in a solution containing all precursor salts. The microsensor displayed good stability in neutral and alkaline media and had a nonstop working lifetime of up to 12 hours. The amperometric response time varied from 5 to 15 s depending on the hydrogen peroxide concentration level. The newly developed electrochemical microsensor exhibited a highly linear behavior in the examined concentration range from 5 to 1000 mu mol L-1 (R-2 = 0.999), an LoD (3 sigma) of 0.9 mu mol L-1, and a favorable reproducibility with a calculated RSD of 2.9% (n=6) for 100 mu mol L-1 hydrogen peroxide, thus holding great promise for its further application in real samples and its exploitation in combination with biorecognition elements in advanced microbiosensor design.