Direct Injection Analysis of Ultra‑Short Chain PFAS in Landfill Groundwater via Altura Column and LC‑MS/MS

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

Prepared by E. Parry1, I. Huang2, M. Chang1
1 - Agilent Technologies, 2850 Centerville Rd, Wilmington, Delaware, 19808, United States
2 - Agilent Technologies, 5301 Stevens Creek Blvd, Santa Clara, CA, 95051, United States


Contact Information: [email protected]; 302-358-7390

ABSTRACT

The increasing detection of ultra short chain per and polyfluoroalkyl substances (PFAS) in environmental waters has intensified the need for analytical methods capable of sensitively and reliably quantifying these poorly retained compounds. Ultra short chain PFAS such as TFA and DFA exhibit minimal retention on conventional C18 columns, necessitating specialized stationary phases, optimized mobile phase conditions, and strict contamination control. This study evaluates the performance of the new mixed mode Altura Poroshell 120 PFAS Column coupled with an Agilent 1290 Infinity III LC and 6495D LC/TQ for the analysis of ultra short chain PFAS in synthetic matrices and landfill groundwater.
Three water types were used: reverse osmosis (RO) water for calibration, synthetic high ionic strength water to challenge method robustness, and groundwater collected during routine landfill monitoring. Synthetic matrices supported retention time and recovery experiments, while groundwater results were compared with matched EPA Method1633A extractions generated by an external collaborator. Samples were vortexed, centrifuged, and fortified with two isotopically labeled internal standards prior to analysis. The method was optimized specifically for improved retention and detection of early eluting PFAS.
Retention times in synthetic high ionic strength water shifted slightly forward relative to RO standards, with the largest shift of 0.1 min for PFPrA. Groundwater samples showed retention times consistent with RO standards. Spike recovery experiments demonstrated recoveries of 70–130% for most compounds, with acceptable precision. DFA exhibited matrix suppression, likely resolvable with a labeled analogue, while elevated TFA variability reflected environmental contamination in a mixed use laboratory. Groundwater samples from seven landfills demonstrated frequent occurrence of ultra short chain PFAS; TFA was detected in all sites tested, followed by PFPrA, PFMeS, DFA, and PFBA. Comparison of PFBA concentrations between the direct injection method and EPA Method1633A extractions yielded a trendline slope of 0.84, indicating agreement between the two approaches over the evaluated range.