Putting the (Atmospheric) Pressure on Forever Chemicals: A Targeted Analysis of GC Amenable PFAS using APGC–MS/MS

Per- and Polyfluoroalkyl Substances (PFAS) in the Environment
Oral Presentation

Prepared by K. Organtini, K. Rosnack, F. Dorman, K. Stup, N. Meruva, S. Oehrle
Waters Corporation, 34 Maple St, Milford, MA, 01757, United States


Contact Information: [email protected]; 508-482-3242

ABSTRACT

Analysis of per- and polyfluoro alkyl substances (PFAS) is routinely performed by laboratories around the globe using liquid chromatography coupled to mass spectrometry. This technique is sufficient to cover an extensive list of compounds, but is not well suited for analysis of more volatile classes of PFAS, such as fluorotelomer alcohols and acrylates, among others. As focus continues to expand beyond the routinely monitored compounds and matrices, the addition of gas chromatography coupled to mass spectrometry is becoming an important tool to get a more comprehensive overview of the PFAS composition of a sample. Many of the GC amenable PFAS can be present in a variety of sample types from environmental to food and food packaging.

A method was developed using atmospheric pressure gas chromatography (APGC™) to chromatograph and ionize the GC amenable PFAS of interest. This technique uses nitrogen to ionize the compounds of interest, which is a soft ionization process, allowing for precursor ions to remain intact in the ion source. Ionization for the PFAS compounds covered in this method was aided by using water in the source, otherwise known as proton transfer. To simplify laboratory implementation, nitrogen was also utilized as the carrier gas for this separation. The method developed covers 35 different native PFAS compounds, plus four isotope labelled internal standard, covering PFAS compound classes including fluorotelomer alcohols, acrylates, methylacrylates, sulfonamides, sulfonamidoethanols, and acetates. The use of the APGC allowed for the precursor to remain as the intact [M+H]+ ion, increasing specificity, as compared to a harder ionization technique like electron ionization, in which these compounds are likely to easily fragment.

Environmental samples, previously extracted following EPA Method 1633 and characterized only using LC-MS/MS analysis, were analyzed using the APGC-MS/MS method to determine if any of the targeted GC amenable PFAS were present in the samples.