A tyrosinase biosensor based on ordered mesoporous carbon–Au/l-lysine/Au nanoparticles for simultaneous determination of hydroquinone and catechol

Abstract

A novel biosensor was developed based on tyrosinase immobilization with ordered mesoporous carbon–Au (OMC–Au), L-lysine membrane and Au nanoparticles on a glassy carbon electrode (GCE). It was applied for the simultaneous determination of dihydroxybenzene isomers using differential pulse voltammetry (DPV). The tyrosinase/OMC–Au/L-lysine/Au film was characterized by scanning electron microscopy (SEM) and impedance spectra. Under optimized conditions, the DPV study results for two isomers, hydroquinone (HQ, 1,4-dihydroxybenzene) and catechol (CC, 1,2-dihydroxybenzene) showed low peak potentials, and the peak-to-peak difference was about 135.85 mV, which ensured the anti-interference ability of the biosensor and made simultaneous detection of dihydroxybenzene isomers possible in real samples. DPV peak currents increased linearly with concentration over the range of 4.0 × 10⁻⁷ to 8.0 × 10⁻⁵ M, and the detection limits of hydroquinone and catechol were 5 × 10⁻⁸ M and 2.5 × 10⁻⁸ M (S/N = 3), respectively. The tyrosinase biosensor exhibited good repeatability and stability. In addition, the response mechanism of enzyme catalysed redox on the OMC–Au/L-lysine/Au film modified electrode based on electrochemical study was discussed. The proposed method could be extended for the development of other enzyme-based biosensors.