(203c) Dual Enzyme Biosensor for Detection of Organophosphorus Compounds Using Organophosphorus Hydrolase and Horseradish Peroxidase

Organophosphorus (OP) compounds are neurotoxic compounds that are commonly used as chemical warfare agents and pesticides. Due to their high toxicity, rapid and sensitive field detection of these compounds has been a topic of interest. Previous work in this field involving organophosphorus hydrolase (OPH) has focused on direct amperometric detection of the electroactive hydrolysis products and potentiometric detection of local pH changes. We have developed a novel amperometric dual enzyme biosensor for detection of a large class of OP compounds. The working principle of this biosensor is hydrolysis of OP compounds by organophosphorus hydrolase followed by electrochemical detection of the phenolic leaving groups by horseradish peroxidase. Detection of the phenolic leaving group is carried out at -50mV vs. Ag/AgCl where the noise and background are low and interferences are negligible. Optimization and the analytical characterization studies of this dual enzyme biosensor will be discussed.