We present instrument validation and field test results of a prototype trichloroethylene / benzene / volatile organic compound vapor analyzer. The analyzer provides real-time analysis of VOC concentrations in a range of matrices, including sanitary sewer headspace, soil gas (extracted from GeoProbe sample points), indoor air, and ambient air. We report measurement results as well side-by-side comparisons with accepted analytical instruments. The prototype analyzer measures in 15-minute intervals either continuously or triggered by the user, and reports the concentration and associated diagnostic results immediately. No user intervention or interpretation of raw data is required, nor is routine recalibration. The limits of detection are approximately 0.15 micrograms per cubic meter (μg/m<sup>3</sup>) for both TCE and benzene, and the dynamic range can be selected by the user to extend at least as high as 100,000 μg/m<sup>3</sup> for both analytes. We will report on several use cases showcasing the capability of the instrument, including rapid soil gas screening for near real-time determination of step-out locations, mapping spatial and temporal variability of hazardous air pollutants in sanitary sewer headspace, and method 325 A/B compatible petroleum refinery perimeter monitoring. The instrument is deployed in a compact van with built-in anemometer, GPS, pressure, and temperature logging. The analyzer operates using a combination of high performance broadly tunable cavity ring-down spectroscopy, analyte dispersion, and signal processing to achieve excellent precision, accuracy, and specificity.

Monitoring trichloroethylene, benzene, and other VOCs in air using cavity ring-down spectroscopy and chemical dispersion

253rd National Meeting (2017)

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