Validation of Analysis of Per- and Polyfluoroalkyl Substances in Wastewater Samples Using EPA Method 1633 with a Vacuum-based Automated Solid Phase Extraction System

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

Prepared by T. Hall, R. Addink
Fluid Management Systems, 900 Technology Park Dr, Billerica, Massachusetts, 01821, United States


Contact Information: [email protected]; 617-393-2396

ABSTRACT

In recent years, mounting concerns have emerged regarding the widespread distribution and potential adverse effects of PFAS, particularly notable compounds like PFOS and perfluorooctanoic acid (PFOA). These concerns have prompted intensified scrutiny of their environmental occurrence, fate, and potential impact.

In the United States the Environmental Protection Agency has released several methods for PFAS, method 1633 being the most recent. This method is very comprehensive, describing analysis of 40 native PFAS with 24 labeled surrogates. The method comprises a wide variety of matrices, including biosolids, fish tissue, ground water, landfill leachate, soil, surface water, and wastewater.

For water samples, Solid Phase Extraction (SPE) has developed over the last few decades into a fast and reliable method of analysis. An automated vacuum-based system was designed with a minimum number of valves in mind and a short and simple pathway from sample jar to cartridge for difficult samples (such as high particle load).

The chemicals used in the process are 1% methanolic ammonium hydroxide, formic acid in water, reagent water, and formic acid in methanol. Sample loading is facilitated by a vacuum pump, while conditioning and elution are carried out using positive pressure. Cartridge drying is achieved with vacuum/nitrogen. Bottle rinses are done using nitrogen to spray the bottle. The resulting extracts are collected in polypropylene tubes without any further concentration. Additionally, relevant recovery standards are added before the LC/MS analysis.

Analysis of synthetic wastewater resulted in all 40 native and 24 labeled compounds falling within the acceptable range with relative standard deviations (RSDs) < 12%. Very low native background from the system was observed (< 0.03 ng/L). The automated system's run time is 70 minutes.

The automated system can run particulate-laden samples with no pretreatment due to the short fluid path, eliminating the possibility of plugged valves and damaged pumps.