Disposable Nitrite Sensor Based on Hemoglobin-Colloidal Gold Nanoparticle Modified Screen-Printed Electrode

Abstract

Abstract 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 −0.224 V (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 −46.4 mV 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 × 10−7 to 7.0 × 10−4 mol dm−3 and a detection limit of 1.0 × 10−7 mol dm−3 at 3σ. 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.