A nitrite and hydrogen peroxide sensor based on Hb adsorbed on Au nanorods and graphene oxide coated by polydopamine

Abstract

A novel hemoglobin (Hb) electrode modified with Au nanorods (AuNRs) and graphene oxide sheets (GOs) coated by polydopamine (Pdop) (GOs@Pdop) was fabricated and used for highly selective and sensitive determination of nitrite (NO2−) and hydrogen peroxide (H2O2). The electrochemical characteristics of the sensor were studied by cyclic voltammetry and chronoamperometry. The GOs@Pdop composite was characterized by Fourier transform infrared (FTIR), ultraviolet-vis absorption spectroscopy (UV-vis) and transmission electron microscopy (TEM). The system was optimized to realize a reliable determination of NO2− at 0.7 V with a detection limit of 2.5 × 10−8 M and H2O2 at –0.2 V with a detection limit of 2.0 × 10−6 M (S/N = 3). The apparent Michaelis–Menten constants (KappM) were calculated to be 0.13 mM for NO2− and 0.70 mM for H2O2. Moreover, the sensor obtained from this study exhibited high sensitivity, good reproducibility, and long-term stability.