Theme: 07. Per- and Polyfluorinated Alkyl Substances (PFAS)

Topic Area: 7m. PFAS Site Characterization

Formatted Title:

Development of a Field-Ready PFAS Sensor

Background/Objectives:

Per- and polyfluoroalkyl compounds are a class of substances that have found use in industrial and commercial manufacturing over the last six decades. Recent studies have been performed on the deleterious effects of PFAS on human health and the environment. Existing market estimates place the size of the environmental liability in the US at over $80 billion. In March 2023, the EPA announced a proposed national Primary Drinking Water Regulation (PDWR) for six PFAS compounds, including PFOA, PFOS, PFNA, HFPO-DA (commonly known as GenX), PFHxS, & PFBS. The current process for the detection of PFAS compounds in groundwater includes collection of water samples and sending them to labs for analysis and certification. This testing procedure takes weeks to complete. The sheer volume of samples causes this process to be expensive and time-consuming. There is an urgent need for a field-ready/hand-held detection system that can quickly measure PFAS compounds at the site and provide relatively accurate results in real time. Allonnia and Salvus have teamed up to develop and deploy a handheld field-ready PFOA sensor with detection limits of 10 parts per trillion. This workflow includes a field-based pre-treatment and pre-concentration of the sample collected to remove interfering organic compounds and concentrate the PFOA to boost sensitivity. We will demonstrate the efficacy of this sensor in lab settings with PFOA spiked MilliQ (clean) water and groundwater samples collected from customer sites. Further, the sensor will be taken to a customer site and used to detect ppt-level PFOA in groundwater.

Approach/Activities:

We have identified a selective matrix to detect PFOA at low concentrations. The sensor uses interferometric detection to quantitatively detect PFOA with high sensitivity. We have further developed and built a field kit for pre-treatment and pre-concentration of the water samples to increase sensitivity and reduce interference. This process includes an extraction process that introduces an organic solvent to preferentially extract PFAS compounds and allow for its use in the sensor.

Results/Lessons Learned:

We have successfully demonstrated the ability of the sensor to detect single-digit parts per billion of PFOA. This rapid detection, combined with a 100X pre-concentration and pre-treatment of the groundwater allows us to detect 10 ppt of PFOA in groundwater with minimal interference of non-fluorinated organic compounds and other PFAS compounds.

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Ron Levin