[Conference Abstract] Identification of per- and polyfluorinated substances in food contact materials by mass spectrometric profiling
By Michaela Lerch, Khanh Hoang Nguyen, Kit Granby
December 30, 2019
Introduction: Food contact materials (FCM) are all types of items intended to be in contact with food fulfilling various tasks like storage or food consumption. Some examples of FCM are coffee filters, pizza boxes, and baking paper. Common materials used to produce FCM are plastic, cardboard, and paper. To improve the functionality of the FCM, chemicals like per‑and polyfluorinated alkyl substances (PFAS) are added to these raw materials. The oleophobic as well as hydrophobic properties of PFAS generate a water and grease resistant material. The potential toxicity, strong persistence in the environment and bioaccumulation of PFAS resulted in an increased control of these chemicals in FCM. Nonetheless, the control-procedures only include tests for a limited number of well-studied PFAS. In a survey authorized by the Danish Veterinary and Food Administration, identified PFAS contributed marginally to the total organic fluorine in some analyzed FCM (unpublished). Based on this fact, it is assumed that unidentified PFAS are present. Identification of these components is of high priority for the consumer protection. Therefore, a screening method for PFAS using high-resolution mass spectrometry was developed and applied to FCM.
Methods: A 6 cm2 piece of each FCM is cut out, placed in an 2 mL Eppendorf-tube and extractedwith 1.5 mL of 50% ethanol in water. The mixture is sonicated for 60 min at 60 °C. Afterwards, the extract is transferred into a 0.2 μm filter vial and internal standard (IS) is added. The IS-spiked extract is injected in a liquid chromatography system coupled to a quadrupole-time of flight mass spectrometer equipped with an electrospray ionization source. The chromatographic separation is performed on a C18 Acquity UPLC CSH column using 2 mM ammonium acetate in water (pH 8.5) as mobile phase A and 2 mM ammonium acetate, 15.5 mM ammonium hydroxide in methanol asmobile phase B. The data is acquired in negative ionization mode and screened against acompound library containing multiple PFAS found in industrial products. Additionally, mass defect filtering techniques are employed.Preliminary Results: The screening revealed multiple PFAS present in FCM. For example indisposable, microwavable plates, the comparison with authentic standards allowed the identification of various PFAS including PFBA, PFPeA, PFHxA, PFHpA, PFDA, and PFOA. For compounds without standards available, such as 1,1,2,2,3,3,4,4,5,5,6,6,7,7,7-pentadecafluoro-N-(4-hydroxybutyl)-N-methylheptane-1-sulfonamide (C12H12F15NO3S) and 3-Methoxyperfluoro(2-methylpentane) (C7H3F13O), MS/MS will be employed to confirm their identity.
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