Detection of phenylhydrazine based on lectin-glycoenzyme multilayer-film modified biosensor

A novel inhibition-based amperometric biosensor of horseradish peroxidase (HRP) for phenylhydrazine detection is described. The multilayer-film modified sensor is prepared by a layer-by-layer deposition of concanavalin A (Con A) and HRP on glassy carbon electrode (GCE), which is forced by the bioaffinity between Con A and mannose residues on the surface of HRP molecule. Hydroquinone is chosen as electron mediator in the system. The performance of the sensor and the optimum experimental conditions are studied. The lower detection limit of the inhibition-based sensor for phenylhydrazine is 1.7 x 10(-6) M, and the linear response range is divided into two parts, one of which is 1.7 x 10(-6) to 1.0(7) x 10(-5) M, and the other 1.07 x 10(-5) to 6.98 x 10(-5) M. The HRP sensor can be reactivated after inhibition and remains more than 91% activity after half a month or frequent running. Interference from phenol, aniline, hydroxylamine, Hg(II), Cd(II) and Bi(III) is found to be minimal, while a high concentration of hydrazine anhydrous, methylhydrazine and 1,1-dimethylhydrazine may interfere with the determination of trace phenylhydrazine. The sensor has been used in phenylhydrazine determination in water of Xiangjiang River.