Amperometric inhibition biosensor for the determination of cyanide

Cyanide compounds have many applications in various industries. These industries discharge large amounts of cyanide contained in their wastewater to the environment which can be dangerous for human life. Therefore, the cyanide detection is important for monitoring and controlling its toxicity. In this study, an amperometric inhibition biosensor has been developed for cyanide determination. Horseradish peroxidase was immobilized on the surface of the working electrode using chitosan and acrylamide. The measurement was conducted at an applied potential of -100 mV versus Ag/AgCl in the 0.1 M phosphate buffer of pH 7.5 in the presence of hydroquinone as electron mediator. Also the effective parameters on the performance of inhibition biosensor including applied potential, pH of electrolyte, mediator concentration and the amount of substrate were optimized. The cyanide determination is obtained in the linear range of 1.64-13.13 mu M with detection limit of 0.43 mu M. The kinetic parameters Michaelis-Menten constant K-app and maximum current I-max without and with inhibitor was calculated and the possible mechanism was analyzed. Also, the common cations and anions in environmental wastewater which may interfere with the detection of cyanide were examined. It was found that the sulfide interference on the enzyme inhibition caused 51.96% error in the determination of cyanide. Finally, the accuracy of proposed biosensor was investigated by real samples. (c) 2013 Elsevier B. V. All rights reserved.