Sensitive electrochemical biosensing of H2O2 based on cobalt nanoparticles synthesised in iron storage protein molecules, ferritin.

ABSTRACT

In this report, a highly sensitive electrochemical biosensor based on cobaltferritin immobilised on a self-assembled monolayer modified gold electrode for determination of hydrogen peroxide (H2O2) in phosphate buffer solution (pH 7.5) was investigated. The modified electrode showed excellent electrochemical activity for oxidation of H2O2. The response to H2O2 on the modified electrode was examined using linear sweep and differential pulse voltammetries. In phosphate buffer (pH 7.5, 0.1 M), the fabricated biosensor exhibited a linear dependence (R = 0.989) on the concentration of H2O2 from 2.49 × 10(-9) to 1.91 × 10(-8) M, a high sensitivity of -0.4099 µA/nM and detection limit of 2.48 × 10(-9) based on a signal-to-noise ratio of 3. Charge transfer coefficient (α) and the exchange current (i0) of oxidation for H2O2 were found to be 0.57 and 7.55 A, respectively. It has been shown that, this modified electrode is able to determine H2O2 with a high sensitivity, low detection limit and high selectivity.