Rapid Pesticide Exposure Analysis Using Surface-Enhanced Raman Spectroscopy

DESCRIPTION (provided by applicant) An inexpensive disposable sensing element that is worn as a vapor exposure monitor or used for urinalysis is proposed for real-time monitoring of pesticide exposure. This sensor, coupled to a battery operated reader, is a direct need for the NIH Exposure Biology Program and has the potential for detect other exposures as well. The sensor is based on Surface-Enhanced Raman Spectroscopy (SERS), which allows precise detection of chemicals that adsorb strongly to roughened SERS sensors, like pesticides, into the high ppt range. The SERS sensors, vapor deposited gold films with subsequent electrochemical roughening, are inexpensive to make, operate in vapor phase under a wide humidity range and in solution. As the sensors are tuned to the analytes of interest, interferences from more concentrated chemicals is limited. In this program, the SERS sensors would be worn as badges to monitor and quantify daily pesticide exposure to a worker by irreversibly binding any pesticide that comes in contact with the SERS sensor. The sensors would also measure pesticide metabolites in urine, providing the NIH with more data on the daily exposure/daily ingestion of pesticides. The SERS sensors will be read using a battery operated Raman instrument with keyed sampling chamber that ensures the SERS sensing elements are automatically aligned into the system. The compact system would be fully automated and incorporate a spectral library with chemometric analysis. Identification and quantification of any detected pesticides would be reported to the field technician. A single reader can be used for evaluation of hundreds of participants. The core concepts of this technology have been developed and demonstrated. Literature results show SERS detection of organochlorine pesticides and EIC Laboratories has detected organophosphate pesticides in vapor and aqueous phases. Field detection of trace levels of explosives has been demonstrated by EIC Laboratories. The two year Phase I program is designed to expand the pesticides studied, demonstrate detection to CDC listed limits, show an adequate usable field lifetime for the SERS sensing elements, design a fieldable reader, perform a detailed interferences analysis and demonstrate that variances in the urine matrix will not affect the SERS measurement precision. Commercial: EIC Laboratories will commercialize the technology by manufacturing the SERS sensors and battery operated Raman readers. The components will be sold commercially through In Photonics, an affiliated company under common ownership.