An ultrasensitive iron(III)-complex based hydrogen peroxide electrochemical sensor based on a nonelectrocatalytic mechanism

In this communication, the first nonelectrocatalysis-type hydrogen peroxide electrochemical sensor is reported. The electroactive iron(III) diethylenetriaminepentaacetic acid (DTPA-Fe(III)) complex is immobilized on the cysteamine (cys) modified nanoporous gold (NPG) films by covalent method. The immobilized DTPA-Fe(III) complex quickly communicates an electron with the electrode. Upon addition of hydrogen peroxide, however, hydrogen peroxide inhibits the direct electron transfer of the DTPA-Fe(III) complex due to the generation of nonelectroactive DTPA-Fe(III)-H2O2 complex. Based on quenching mechanism, the first hydrogen peroxide electrochemical sensor based on a nonelectrocatalytic mechanism is developed. The novel hydrogen peroxide electrochemical sensor has the ultralow detection limit (1.0×10(-14) M) and wide linear range (1.0×10(-13) to 1.0×10(-8) M) with excellent reproducibility and stability.