A novel inhibition biosensor constructed by layer-by-layer technique based on biospecific affinity for the determination of sulfide

Abstract

A novel inhibition biosensor used for detection of sulfide has been present, which does not suffer from interference by the common cations and anions in environmental water. Based on biospecific affinity of concanavalin A (Con A) and horseradish peroxidase (HRP), the multilayer of Con A/HRP bilayer was prepared on the surface of the precursor-modified electrode. Atomic force microscopy and electrochemical impedance spectroscopy were adopted to monitor the uniform layer-by-layer assembly of the Con A/HRP bilayer. The amperometric measurement was carried out at an applied potential of −0.150 V (versus Ag/AgCl) in the present of 0.2 mol L−1 hydroquinone in pH 6.5 phosphate buffer. The parameters influencing the analytical performance, such as the number of assembled bilayers, operating potential, pH of the electrochemical supporting solution, and the concentrations of hydroquinone and hydrogen peroxide, were optimized. The determination of sulfide can be achieved in a linear range of 0.1–38.5 μmol L−1 with a detection limit of 0.05 μmol L−1. The developed biosensor possesses high sensitivity and selectivity, and can be successfully applied to the detection of real waste water.