An electrochemical acetylcholine biosensor based on nanoshells of hollow nickel microspheres-carbon microparticles-Nafion nanocomposite

Electrocatalytic oxidation of acetylcholine (ACh) on different nickel-based composites was investigated. Cyclic voltammetry, steady-state polarization measurements and chronoamperometry were employed to study the mechanism and kinetics of the oxidation process. The results showed that ACh was irreversibly oxidized on nickel nanoshells-carbon microparticles-Nafion nanocomposite with an excellent catalytic activity. The catalytic rate constant and the transfer coefficient for the electrocatalytic oxidation of ACh and the diffusion coefficient of ACh were obtained using cyclic voltammetry, steady-state polarization measurements and chronoamperometry. A sensitive and time-saving hydrodynamic amperometry method was developed for the determination of ACh. The nanocomposite showed a high sensing performance with a sensitivity of 48.58 ± 0.52 mA M−1 cm−2 and a limit of detection of 49.33 nM. The nanocomposite represented many advantages as an ACh biosensor such as simple preparation method without using any specific enzyme or reagent, excellent catalytic activity, high sensitivity, long-term stability, and antifouling property toward ACh and its oxidation product(s). Sensitivity and detection limit of the present biosensor are better than all of the reports appeared in the literature.