Combined Use of Total Fluorine and Oxidative Fingerprinting for Quantitative Determination of Side-Chain Fluorinated Polymers in Textiles
By Ioannis Liagkouridis, Raed Awad, Steffen Schellenberger, Merle M. Plassmann, Ian T. Cousins, and Jonathan P. Benskin
January 3, 2022
Given their extensive production volumes and potential to form persistent perfluoroalkyl acids (PFAAs), there is concern surrounding the ongoing use of side-chain fluorinated polymers (SFPs) in consumer products. Targeted SFP quantification relies on matrix-assisted laser desorption ionization time-of-flight mass spectrometry, which can suffer from poor accuracy and high detection limits. Alternatively, total fluorine (TF)-based methods may be used, but these approaches report concentrations on a “fluorine equivalent” basis (e.g., fluorine per square meter in the case of textiles) and are incapable of elucidating structure or chain length. Here a new method for comprehensive characterization of SFPs is presented, which makes use of the total oxidizable precursor assay for fingerprint-based structural elucidation and combustion ion chromatography for TF quantification. When used in parallel, quantitative determination of SFPs (in units of mass of CnF2n+1 per square meter of textile) is achieved. Expressing SFP concentrations in terms of the mass of the side chain (as opposed to fluorine equivalents) facilitates estimation of both the structure and quantity of PFAA degradation products. As a proof of principle, the method was applied to six unknown SFP-coated medical textiles from Sweden. Four products contained C6-fluorotelomer-based SFPs (concentration range of 36–188 mg of C6F13/m2), one contained a C4-sulfonamide-based SFP (718 mg of C4F9/m2), and one contained a C8-fluorotelomer-based SFP (249 mg of C8F17/m2).
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