Membrane Filter Choice for Preparing PFAS Testing SamplesPer- and Polyfluoroalkyl Substances (PFAS) in the Environment
Poster Presentation
Prepared by L. Lozeau1, R. Muralidharan2, G. Shah1, A. Laws1
1 - MilliporeSigma, 400 Summit Drive, Burlington, MA, 01803, United States
2 - Sigma-Aldrich, Inc., P.O. Box 14508, St. Louis, MO, 63178, United States
Contact Information: [email protected]; 781-496-5656
ABSTRACT
LC-MS/MS-based analytical methods for measuring perfluoroalkyl substances (PFAS) in complex environmental matrices such as wastewater are becoming commonly implemented in testing laboratories. Additional sample preparation steps such as filtration are critically important for producing high quality data for analysis. Two key considerations for consumables that directly contact samples like syringe filters or cut disc membrane filters are to (1) avoid introducing contamination and (2) reduce target analyte binding, both of which could seriously impact the accuracy of analysis. In this series of studies, we chose a variety of membrane filter materials (polyethersulfone, nylon, nylon with a glass fiber pre-filter, hydrophilic and hydrophobic polypropylene, glass fiber, nitrocellulose and mixed cellulose ester), pore sizes (ranging from 0.2 to 5.0µm), diameters (25 vs. 33mm) and formats, and then evaluated their suitability for use in PFAS analytical methods, including EPA 537.1, EPA 1633, and OTM-45. In all cases, analysis was performed using LC-MS/MS with internal standards. We found that none of the filters were contaminated with PFAS compounds at the detection levels tested. However, it was determined that certain physicochemical properties of the filters (pore size, diameter, housing material, filter material) as well as the polarity of the solvent being filtered highly influenced the recovery of different classes of PFAS analytes onto the filter material. These results enable us make recommendations for filter choice based on the method parameters being implemented to improve data quality.
