Accurate Mass Library for PFAS Analysis in Environmental Samples Using High Resolution GC/Q-TOF

Emerging Environmental Applications for High Resolution Mass Spectrometry
Oral Presentation

Prepared by T. Anumol1, L. Wong2, T. Young2, S. Nieto1, M. Giardina1
1 - Agilent, 2850 centerville, Wilmington, DE, 19808, United States
2 - University of California - Davis, , , United States


Contact Information: [email protected]; 13024198909

ABSTRACT

Per- and polyfluoroalkyl substances (PFAS) are emerging contaminants of increasing concern due to their environmental persistence, toxicity, and capability of bioaccumulation. PFAS include a wide range of chemical classes, therefore, a variety of analytical techniques are necessary for their detection. GC/MS is typically used for detecting volatile and non-polar PFAS compounds. In this study we used GC/Q-TOF system to take advantage of high resolution for detecting compounds with negative mass defect in complex environmental matrices. For specific and sensitive PFAS detection, we have first created an accurate mass GC/MS library for PFAS in both EI and CI modes. GC-amenable PFAS standards have been used to obtain accurate mass spectra. Soil and plant samples were extracted using a modified QuEChERS protocol.
In order to create an accurate mass GC/MS Personal Compound Database and Library (PCDL), the spectra have been collected in both EI and positive CI modes for over a hundred PFAS compounds. The PFAS compound classes included perfluoroalkyl iodides (PFAIs), fluorotelomer iodides (FTIs), fluorotelomer alcohols (FTOHs), fluorotelomer olefins (FTOs), fluorotelomer acrylates (FTACs), fluorotelomer methacrylates (FTACs) and perfluoroalkyl carboxylic acids (PFCAs) among others.
Accurate mass fragment ions have been automatically annotated with formulas based on accurate mass information and isotope ratios using MassHunter Qualitative Analysis software. The fragment formula annotations were manually verified, corrected when necessary and automatically converted to the theoretical m/z. Kovats retention indices have also been calculated for each compound.
The accurate mass PFAS library was evaluated using soil, plant and water extracts and data will be presented to show how non-target analysis on GC-Q/TOF can expand our knowledge of PFAS detection and help fill the overall mass balance.