An Investigation of Contamination and Recovery of PFAS in Analytical Methods that Require Filter Membranes

Polyfluoroalkyl Substances (PFAS) in the Environment
Oral Presentation

Presented by T. Reynolds
Prepared by L. Lozeau
MilliporeSigma, 400 Summit Drive, Burlington, Massachusetts, 01803, United States


Contact Information: [email protected]; 781-496-5656

ABSTRACT

Methods for measuring perfluoroalkyl substances (PFAS) in various matrices using LC-MS/MS have been established by regulatory agencies in recent years, as there is mounting evidence of widespread contamination in the environment and negative impacts to human health. A key consideration for any PFAS method is to avoid contamination from consumables, equipment and reagents that come into contact with samples, which could seriously impact the accuracy of analyses. On the other hand, analyte binding could also occur onto consumables, leading to lower recoveries. PFAS methods for a variety of matrices (such as ASTM D7979, EPA Draft 1633 and OTM-45) require filtration, either with a syringe filter or disc membrane filter. No matter which filtration format is used, the concerns of PFAS contamination or non-specific binding onto filter consumables remains the same, which is why it is critical to better understand these properties.

First, water spiked with C13 labeled standards was filtered with multiple syringe filter types and pore sizes, to investigate and compare PFAS contamination, using EPA 537.1 as a guideline. Hydrophilic and hydrophobic polypropylene disc membrane filters were also investigated. None of the syringe filters or disc membrane filters demonstrated detectable PFAS extractables in water or basic methanol (ppb levels), and methanol reduced non-specific binding of C13 labeled standards. Next, percent recovery studies (ppt levels) were carried out with nylon syringe filters (25mm and 33mm diameter) in an aqueous matrix spiked with 40 PFAS compounds with standards, and analyzed according to EPA Draft 1633. Recovery varied depending on the filter manufacturer and diameter, PFAS compound class, and original spiking concentration.

These data show that syringe filters of polyethersulfone, nylon, and nylon with a glass fiber prefilter, and disc membrane filters of polypropylene may all be used to filter samples for PFAS quantitation.