Analysis of PFAS & Separation of Bile Salts Using SelectraCore C18 HPLC Column by LC-MS/MS with gas supplied by a PEAK Scientific nitrogen gas generator.

Content originally presented at ASMS 2024 by Arielle Cocozza at United Chemical Technologies. You can download the original poster in United Chemical Technologies' Resource section.

Per- and polyfluoralkyl substances (PFAS) are a group of synthetic organofluoride compounds widely used in industry and consumer products, which are highly persistent and bioaccumulative, which has led to increased focus on their presence in the environment.

EPA 1633, introduced in 2021, expanded EPA’s methods to measure 40 PFAS analytes across different matrices. The method, updated in January 2024, mandates a 1-minute separation between TDCA and PFOS. The study below investigates PFAS analysis per EPA 1633 using UCT’s SelectraCore C18 HPLC column for optimized separation of analytes, without compromising run-time and gas supply to the LC-MS by a PEAK Scientific gas generator, to minimize impact of environmental contaminants on the analysis (figure 1 & 2).  

Figure 1. HPLC conditions for PFAS analysis

Figure 2. MS conditions for PFAS analysis

Despite achieving a 0.5-minute shorter runtime than EPA’s method while maintaining a 1.4-minute TDCA-PFOS separation, samples extracted with UCT’s EXWAXCB cartridges demonstrated high accuracy and precision under this method. The benefits of using a PEAK gas generator during this analysis include the reduction in analysis time as well as the detection of analytes at levels below the minimum detection limit required by the EPA. The %RSD was below 10% for almost all compounds tested (figure 2) which shows excellent repeatability, highlighting the consistent gas quality and overall system stability.

Figure 3. Analyte calibration curve linearity, percentage recovery and percentage RSD

Figure 4. Calibration curves for HFPO-DA, PFHxS and FTS

Figure 5. Chromatograms showing critical separation of analytes