Biosensor for Field Monitoring of Pesticides in Water
EPA Phase I Contract No. EP-D-05-025
The goal of this Phase I program was to demonstrate feasibility for the use of an enzyme inhibition biosensor for detection of organophosphate and carbamate pesticides in water. Key to this program was the question of feasibility concerning fabrication of the biosensor in a mass-producible format which would allow cost-effective field monitoring at a price competitive with laboratory analysis.
During the Phase I program, methods were investigated for preparation of the biosensor chip and biosensors prepared by promising approaches were continued on to testing and characterization with a variety of pesticides.
Biosensors were fabricated using several formulations containing acetylcholinesterase (AChE), a conductive carbon material and a binder. Two particular formulations, one using a commercial carbon black and the other a commercial glassy carbon powder, proved to be especially useful for screen-printing biosensor electrodes. Both formulations were capable of sub-ppm detection of representative carbamide and organophosphate pesticides. Glassy carbon screen printing ink formulations proved to have superior reproducibility and stability compared to others tested.
Biosensors prepared by screen printing in a microscale format are effective for detection of a variety of common pesticides at sub-ppm concentrations. These sensors may be mass produced at considerable cost savings to make them economically competitive with sample-and-transport laboratory based analysis. Cost reduction through use of field screening methods will improve the efficiency and cost effectiveness of monitoring activities.