Grantee Research Project Results
Final Report: Field-Portable Fluorescence Sensor for Polycyclic Aromatic Hydrocarbons
EPA Contract Number: EPD05041Title: Field-Portable Fluorescence Sensor for Polycyclic Aromatic Hydrocarbons
Investigators: Peterson, Kristen
Small Business: Southwest Sciences Inc.
EPA Contact: Richards, April
Phase: I
Project Period: March 1, 2005 through August 31, 2005
Project Amount: $70,000
RFA: Small Business Innovation Research (SBIR) - Phase I (2005) RFA Text | Recipients Lists
Research Category: Small Business Innovation Research (SBIR) , Hazardous Waste/Remediation , SBIR - Waste
Description:
The purpose of this research project was to design, build, and test a real-time, field-portable instrument for the detection of organic chemical pollutants. Southwest Sciences, Inc.’s technology uses time- and wavelength-resolved fluorescence spectroscopy (T&WFS) to detect and quantify pollutants such as polycyclic aromatic hydrocarbons (PAHs). The instrument incorporates an innovative approach to fluorescence lifetime detection that is based on radio frequency electronics and is less expensive than other approaches to T&WFS. A resulting commercial instrument will be compact, cost effective, and reliable. The entire instrument, including the diode laser optics, detector, electronics, and computer, will fit into a space the size of a large briefcase and will be capable of running on batteries.
Summary/Accomplishments (Outputs/Outcomes):
Phase I work demonstrated that this method has the temporal response needed to measure the wide range of lifetimes associated with PAHs. The sensitivity of the current benchtop instrument is sufficient for measuring benzo(a)pyrene at its solubility concentration in water (4 ppb). Anthracene and benzo(g,h,i)perylene can be measured in the few tens of ppb concentrations. These measurements are encouraging, but if this method is to be useful for measurements of water contamination across a wide range of PAHs, the sensitivity needs to be improved. Southwest Sciences, Inc., identified several changes that can be made to the instrument to improve the detection sensitivity.
Conclusions:
Although the Phase I research project did not reach all of the proposed goals, it demonstrates that the T&WFS approach is feasible for PAH detection in a field instrument. Several possible approaches to improving the sensitivity to detect lower concentrations and a wider variety of compounds were examined. A market niche survey indicated that potential users are more interested in detecting PAHs in soil than in water. In this case, higher concentrations are likely and the current instrument already may have sufficient sensitivity. It also may be possible to pre-concentrate water samples prior to measurements. The Phase I results should warrant further investigation and improvement of this technology in Phase II.
Beyond sensitivity improvements, two important issues remain to be addressed in Phase II: (1) Can this approach identify individual PAHs in a mixture of two or more compounds? and (2) To what extent does background fluorescence from naturally occurring organic substances interfere?
Supplemental Keywords:
field-portable fluorescence sensor, polycyclic aromatic hydrocarbons, PAHs, organic chemical pollutants, time- and wavelength-resolved fluorescence spectroscopy, T&WFS, radio frequency electronics, detector, diode laser optics, benzo(a)pyrene, anthracene, benzo(g,h,i)perylene, EPA, small business, SBIR,, RFA, Scientific Discipline, INTERNATIONAL COOPERATION, Ecosystem Protection/Environmental Exposure & Risk, Environmental Chemistry, Waste, Monitoring/Modeling, Environmental Monitoring, Environmental Engineering, monitoring, environmental measurement, field portable monitoring, field monitoring, hazardous waste, PAH, field deployable, fluorescence detection, remediation, diode laser based monitoringThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.