Superfund Research Program
Rapid Real-Time High-Sensitivity Trichloroethylene Vapor Analyzer
Project Leader: Bruce A. Richman
Grant Number: R43ES022538
Funding Period: Phase I: February 2013 – July 2014
This project is addressing the need for a trace trichloroethylene (TCE) vapor sensor. TCE is a toxic volatile organic compound (VOC) used as an industrial solvent. TCE is a common soil contaminant at industrial toxic waste sites, and it migrates through the soil away from the original contamination site. TCE vapor intrusion into buildings from contaminated soil concentrates the TCE vapor indoors, where it poses a health risk to the occupants. Currently, TCE is monitored by capturing it with chemically active materials, and then analyzing those materials in a laboratory; the measurement interval is hours or days. A real-time monitor with a measurement interval of minutes would enable real- time mapping of the TCE concentration within a building to locate vapor intrusion points of ingress and to monitor the quantity of TCE entering the building. The mapping distinguishes TCE entering the building from indoor sources of TCE.
Entanglement Technologies is determining the feasibility of developing a TCE vapor sensor based on the combination of cavity ring-down spectroscopy (CRDS) and diffusion time-of-flight (DiTOF) incorporating stationary phases (as in gas chromatography). CRDS provides extremely sensitive detection while diffusion with stationary phase provides specificity. The research objective for phase I is to demonstrate selective TCE vapor detection in air in the presence of other VOCs and atmospheric components (such as carbon dioxide and water vapor).
The project involves building a table-top CRDS/DiTOF prototype gas analyzer to test with TCE and other VOCs. The anticipated TCE sensitivity is 20 parts per trillion by volume (pptv) in a measurement time of approximately 10 minutes, surpassing existing technologies.