Automated Liquid Calibration Inlet for Online Measurements of Airborne PFAS

CHENYANG BI, Michael Davern, Clara Eichler, Mitchell Alton, Anita Avery, Nathan Kreisberg, Barbara Turpin, Jason Surratt, John Jayne, Manjula Canagaratna, Aerodyne Research Inc.

     Abstract Number: 463
     Working Group: Chemicals of Emerging Concern in Aerosol: Sources, Transformations, and Impacts

Abstract
Per- and polyfluoroalkyl substances (PFAS), also known as “forever chemicals”, are widely used as water-resistant coatings and surfactants in many consumer products. They may not strongly bond to the polymer matrix and can leach out of the source products, making exposure to those potentially toxic chemicals an important concern. PFAS in air are traditionally collected and then analyzed offline. These “offline” sampling techniques are often time-consuming and can cause losses of more volatile species. Some early attempts have been made to apply online chemical ionization time-of-flight mass spectrometers (CI-TOF-MS) for PFAS measurements in the air. However, challenges remain with the in-situ, automatic calibration of the instruments for measuring PFAS. In this work, we demonstrated an automated inlet for online liquid calibration that is compatible with Vocus CI-TOF-MS. The inlet supports in situ, programmed calibrations using liquid chemical standards for online quantification of airborne PFAS such as fluorotelomer alcohols (FTOHs), fluorotelomer diol (FTdiOHs), perfluorooctane sulfonamide ethanols (FOSEs), and perfluorooctane sulfonamides (FOSAs) with detection limits ranging from 0.2 to 2.7 pptv. As a proof-of-concept demonstration of the setup, the calibrated online mass spectrometers were applied to repeat previously reported measurements of PFAS emission rates from a variety of known sources present in indoor and outdoor environments.