Disposable nitrite sensor based on hemoglobin-colloidal gold nanoparticle modified screen-printed electrode

An unmediated, disposable nitrite amperometric biosensor based on hemoglobin (Hb)-colloidal gold nanoparticle modified screen-printed carbon electrode (Hb-Au-SPCE) was proposed. The immobilized Hb showed a couple of quasi-reversible redox peak with a formal potential of -0.224V (vs. SCE) in 0.2 mol dm(-3) pH 5.5 NaAc-HAc buffer. The formal potential changed linearly between pH 4.0 to 9.0 with a slope of -46.4mV pH(-1). The Hb-Au-SPCE displayed a rapid amperometric response to the reduction of nitrite, which allowed to be used for the determination of nitrite with a linear range from 3.0 x 10(-7) to 7.0 x 10(-4) mol dm(-3) and a detection limit of 1.0 X 10(-7) mol dm(-3) at 3sigma. The amperometric sensor had a high sensitivity, good accuracy, and stability and is simple to use, lost-cost, rapid for the nitrite quantitative detection in practical applications.