The Analysis of Polyfluorinated Alkyl Substances (PFAS) in Environmental Samples by Optimized ASTM Method 7968/7979

Characterization of Polyfluoroalkyl Substances in the Environment
Oral Presentation

Prepared by , T. Ogura, W. Lipps

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There has been an increasing awareness of the presence of PFAAs in water. A simple and robust method with quick turn-around time to determine these compounds is essential to provide accurate responses in a timely manner. Direct injection without SPE allow us to maximize throughput and to minimize background caused by the sample preparation step. We used Liquid Chromatography / triple quadrupole mass spectrometer to analyze the fluorotelomer and unsaturated fluorotelomer acids included in ASTM method 7968/7979. Fluorotelomer acids are observed as [M-H] - and [M-HF-H]-. Since the loss of HF in the fluorotelomer acids results in an ion with the same formula as the unsaturated fluorotelomer acids, and these two classes of compounds showed very similar retention times, we reduced ESI heater temperature to reduce HF loss and minimize false identifications. For method validation, we tested sample stability, effect of contaminant in mobile phase, etc. Calibration range and detection limit meet specified value. We also analyzed samples including tap water and surface water to validate optimized method.