Preparation of multiwalled carbon nanotube-chitosan-alcohol dehydrogenase nanobiocomposite for amperometric detection of ethanol

An amperometric biosensor for the determination of ethanol has been constructed using a nanobiocomposite film. This film is made up of a conduit of multiwalled carbon nanotubes (MWCNTs), a chitosan (CHIT) binder, and an alcohol dehydrogenase (ADH) function. The MWCNT-CHIT-ADH nanobiocomposite film is cast on a glassy carbon electrode. Homogeneity of the resulting nanobiocomposite film was investigated by field emission scanning electron microscopy. Electrocatalytic activity of the MWCNT-CHIT-ADH nanobiocomposite was determined using cyclic voltammetry and amperometry. Optimum conditions of the biosensor were experimentally determined through varying several important parameters. These included working potential, solution pH value, NAD+ concentration, and enzyme loading. The optimized biosensor shows a sensitivity of 0.1646 A M−1 cm−2, an apparent Michaelis–Menten constant of 0.38 mM, and a detection limit of 0.52 μM. The applicability of the proposed biosensor based on MWCNT-CHIT-ADH nanobiocomposite was tested by the detection of ethanol in beer, red wine, and spirit.