Polymer-Based Competitive Flow Sensor Detects Contaminants in the Field

This Phase II project addresses the development of technology that would provide field-based quantitative detection of a wide range of environmental contaminants through the use of molecularly imprinted polymers and fluorescence detection. The proposed method would complement immunological methods of analysis that have been adapted to contaminants such as herbicides and pesticides. The well-documented advantages of these methods, including high sensitivity and selectivity and fairly low cost per analysis, are offset by a number of disadvantages. Antibodies have somewhat limited physical and chemical durability and cannot be used at elevated temperatures, beyond a fairly restricted pH range or in nonaqueous environments. In the Phase I program, American Research Corporation of Virginia developed a compact displacement flow sensor utilizing molecularly imprinted polymer (MIP) technology and diode laser-excited near-infrared fluorescence detection. In the Phase II program, work will be performed to optimize and field test the MIP sensor. The innovation of the Phase II program is the development and use of a new generation of biomimetic MIP to provide analyte selectivity and down-stream near-infrared fluorescence as a sensitive means of detection. Phase II also will address the selectivity of the MIP system. The Phase I results have shown that MIP specific for atrazine and 2,4-D can be conveniently prepared and processed. Methods were developed to fabricate rapidly interchangeable cartridges. A low-cost diode-laser based fluorimeter was developed and shown to be capable of extremely low detection limits and very stable operation. Synthetic strategies for preparing fluorophore labeled analyte molecules were developed. The Phase II technical objectives include the preparation of MIP and competition reagents and development of assay methodology optimized for environmental analysis, and fabrication extensive testing of the sensor system.