Disposable biosensor based on a hemoglobin colloidal gold-modified screen-printed electrode for determination of hydrogen peroxide

A disposable reagentless hydrogen peroxide biosensor based on the direct electrochemistry of hemoglobin immobilized on a colloidal gold-modified screen-printed carbon electrode (Hb-Au-SPCE) was proposed. The electrochemical behavior of immobilized Hb at a SPCE was studied for the first time. The electrode reaction of immobilized Hb showed a surface-controlled process with an electron transfer rate constant of (0.40 ± 0.02) s^-1 determined in the scan rate range from 25 to 200 mV s^-1. The Hb-Au-SPCE exhibited an electrocatalytic activity toward the reduction of hydrogen peroxide with a K_M^app value of 1.8 mM, which was allowed to be used as a disposable sensor for determination of hydrogen peroxide with a linear range from 1.0 × 10^-5 M to 3.2 × 10^-4 M, a detection limit of 5.5 × 10^-6 M at 3σ, a high sensitivity, fast response, and good selectivity, accuracy, and reproducibility. The disposable reagentless sensor was stable, low cost, and simple to use for detection of hydrogen peroxide in real samples.