Moving Beyond Monitoring Legacy Per and Polyfluoroalkyl Substances (PFAS): Screening Strategies for the Growing List.

Oral Presentation

Prepared by J. Pyke1, T. Anumol2, H. Zhao2
1 - Agilent Technologies, Inc., 5301 Stevens Creek Blvd, Santa Clara, California, 95051, United States
2 - Agilent Technologies, Inc., 2850 Centerville Road, Wilmington, DE, 19808, United States


Contact Information: james_pyke@agilent.com; +14085534321


ABSTRACT

Per/Polyfluoroalkyl substances (PFAS), are substances that have uniquely desirable properties for use in various industries. However, their wide-ranging use leads to emission into the environment, and as PFAS are persistent and bioaccumulative in the environment and wildlife, they are contaminants of concern.
Traditionally, methods such as USEPA 537 and ASTM 7979 are designed to monitor a small and discrete number of PFAS compounds, thought to be end-products of degradation processes occurring in environmental systems. However, the total fluorinated compounds in a sample may be underestimated by not monitoring the precursor compounds of which these compounds are formed from. Sample preparation techniques such as the Total Oxidizable Precursor (TOP) Assay attempt to measure the total fluorinated compounds by forcing degradation of precursors into measurable end-products. However, this technique is time consuming and may not degrade all precursors into measurable end-products. Additionally, some countries decided to phase out specific classes of PFAS manufacturing and use, which has led manufactures to find alternative classes of PFAS, leading to new precursors and degradation products being found in environmental samples.
Identifying PFAS precursors present in an environmental sample may impact decisions in treatment processes at remediation sites and help deduce possible degradation products that could exist in the environment. Consequently, scientists are contributing PFAS to various publicly available databases: growing the list of precursors and degradation by-products, some listing more than 4000 entries. Traditional instruments, such as LC-QQQ technology, are targeted to quantify commonly monitored PFAS end-products. Without standards, adding more compounds to a LC-QQQ assay is restrictive and it would be logistically difficult to monitor all possible precursors.LC-QTOF technology allows the simultaneous quantification of commonly monitored PFAS whilst acquiring untargeted data that can be screened for suspected PFAS precursors. The nature of the data acquired also allows for retrospective detection of new PFAS as the scientific community learns more about these emerging contaminants.
This presentation highlights the benefit of untargeted technology used to screen new PFAS without compromised typical targeted analytical requirements such as precision, sensitivity, linear dynamic range and robustness.