Balancing Matrix Removal and Analyte Recovery in PFAS Analysis of Landfill Leachate

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

Prepared by C. Shields1, J. Borny2, N. Ruiz2, O. Salawu2, D. Tran1, C. Via1, S. Krepich1
1 - Sciex, 1201 Radio Road, Redwood City, California, 94065, United States
2 - Lummus Technology, 13001 Bay Park RD, Pasadena, Texas, 77507, United States


Contact Information: [email protected]; 662-419-6249

ABSTRACT

Per- and polyfluoroalkyl substances (PFAS) present a growing analytical challenge in complex environmental matrices such as landfill leachate, where high organic loads and matrix interferences can hinder quantitative analysis by liquid chromatography–mass spectrometry (LC-MS). Standard sample preparation workflows for PFAS, including the use of combination solid-phase extraction (SPE) cartridges such as the Phenomenex Strata® PFAS cartridge, routinely provide adequate cleanup for relatively clean aqueous samples. However, landfill leachate often contains elevated levels of humic substances, colloids, suspended solids, and organic contaminants that can overwhelm conventional SPE cleanup and compromise instrument performance, analyte recovery, and data quality.
In this study, we evaluated an enhanced sample preparation workflow designed to improve matrix removal for landfill leachate analysis. A landfill leachate sample was processed using two approaches: (1) standard SPE cleanup, and (2) SPE followed by an additional dispersive SPE (dSPE) cleanup step using the Phenomenex ROQ QuEChERS kit containing 150 mg MgSO₄, 50 mg PSA, and 50 mg GCB in a 2 mL vial. Sample appearance and clarity improved substantially with the added dSPE step, indicating more effective removal of co-extracted matrix components. However, this improvement came at the cost of reduced PFAS recovery.
Across the 33 analytes targeted, the inclusion of the dSPE step led to an average recovery decrease of approximately 20%. Certain analytes experienced disproportionately large losses; for example, PFHpA exhibited a recovery reduction of 85% compared with SPE alone. These findings highlight a tradeoff between matrix cleanliness and analytical sensitivity when applying aggressive cleanup strategies to highly contaminated samples. Further optimization, including modified sorbent proportions, reduced contact time, or targeted cleanup strategies—may help balance recovery and matrix removal for challenging landfill leachate PFAS analyses.