Techniques for the determination of PFAS (per- and polyfluoroalkyl substances)
(04.03.2025)
The key technologies used for PFAS detection are a fascinating mix of cutting-edge chemistry and high-precision instrumental techniques.
PFAS stands for Per- and Polyfluoroalkyl Substances — a large group of human-made chemicals known for their strong carbon-fluorine bonds. These bonds make PFAS incredibly resistant to heat, water, and oil, giving them their famous non-stick, waterproof, and stain-resistant properties.
Here’s a quick breakdown of what the terms mean:
Perfluoroalkyl substances: All the hydrogen atoms in the carbon chain are replaced by fluorine atoms — making the compound fully fluorinated (e.g., PFOA and PFOS).
Polyfluoroalkyl substances: Some hydrogen atoms remain in the carbon chain, so the compound is only partially fluorinated.
Because these chemicals don’t break down easily, they’re often called "forever chemicals" — persisting in the environment for years and accumulating in water, soil, wildlife, and even human blood.
The OECD (Organisation for Economic Co-operation and Development) now defines PFAS broadly as:
Fluorinated substances that contain at least one fully fluorinated carbon atom — excluding substances with only a single fluorinated methyl or methylene group.
This wide definition reflects growing concern about the entire class of PFAS chemicals, not just a few well-known ones like PFOA and PFOS.
The most commonly used techniques for the determination of PFAS include:
1. Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)
Why it's used: LC-MS/MS is the gold standard for PFAS analysis, especially for water, soil, and biological samples.
How it works:
Liquid chromatography (LC) separates the PFAS compounds in a sample.
Tandem mass spectrometry (MS/MS) then ionizes and fragments these molecules, detecting them based on their mass-to-charge ratio.
Strengths: Ultra-sensitive, detecting PFAS at parts-per-trillion (ppt) levels or lower. It’s precise enough to identify specific PFAS variants, like PFOA and PFOS.
Challenges: Needs rigorous calibration and regular maintenance since the smallest contamination (like from Teflon lab equipment!) can throw off results.
2. High-Resolution Mass Spectrometry (HRMS)
Why it's used: HRMS is even more advanced — useful for identifying unknown or emerging PFAS.
How it works: Similar to LC-MS/MS, but with higher resolution, allowing scientists to detect minute differences in mass and uncover previously unidentified PFAS compounds.
Strengths: Critical for studying PFAS transformation products or "precursor" compounds that may not be caught by targeted methods.
Challenges: Expensive and complex, requiring highly trained analysts.
3. Total Oxidizable Precursor (TOP) Assay
Why it's used: Standard PFAS tests might miss hidden or precursor compounds. The TOP assay helps estimate total PFAS burden by chemically oxidizing precursors into detectable forms.
How it works: Samples are treated with a strong oxidant, breaking down PFAS precursors into known terminal compounds like PFOA or PFOS. These can then be measured using LC-MS/MS.
Strengths: Offers a broader picture of PFAS contamination, not just the common compounds.
Challenges: Doesn’t identify which precursors were present — just how much they transformed into detectable PFAS.
4. Combustion Ion Chromatography (CIC)
Why it's used: CIC measures total organic fluorine (TOF) — an indicator of overall PFAS levels, even if the individual compounds aren’t identified.
How it works: The sample is combusted, converting fluorine-containing compounds into hydrogen fluoride (HF), which is then measured using ion chromatography.
Strengths: Useful for detecting PFAS as a class, not just known compounds. Non-targeted analysis is thought to be a better risk assessment tool for measuring the true impact of fluorine on the environment.
Challenges: Lacks specificity — you can’t tell which PFAS are present, only that fluorinated compounds exist.
5. Non-Targeted Analysis (NTA)
Why it's used: NTA searches for unknown or emerging PFAS by casting a wide net — crucial as new compounds keep popping up.
How it works: Usually paired with HRMS, this method scans for chemical signatures without pre-selecting target compounds.
Strengths: Great for discovering new or unexpected PFAS, helping stay ahead of industry shifts.
Challenges: Complex data analysis and computational modeling are needed to interpret the results — it’s not a simple "yes/no" test.
6. Fluorine Specific Group Methods
Available techniques: Continuum source graphite furnace molecular absorption spectroscopy (HR -
CS - GF - MAS), Inductively coupled plasma mass spectrometry (ICP-MS/MS), PIGE and µ-X-ray Fluorescence
Why it's used: Quantification of the fluor content
without knowledge of the source compound
Strengths: Allowing for F-mass balance, giving hints for undetected compounds
Challenges: Sensitivity is poorer than for target LC-MS
7. Group Methods specific for perfluorinated substances
Available Techniques: FTICR, 19F-NMR and XANES
Why it's used: identifying new PFAS.
Strengths: Providing additional information on compound structure
Callenges: Poor sensitivity does not allow for ultra-trace analysis
8. Sensor-Based Approaches (Emerging Techniques)
Surface-Enhanced Raman Spectroscopy (SERS): Being explored for rapid, field-based detection.
Electrochemical Sensors: Investigated for real-time PFAS monitoring in water systems — but still in early stages.
Strengths: Could allow for faster, on-site PFAS screening without needing to send samples to a lab.
Challenges: These methods lack the sensitivity and reliability of established techniques (like LC-MS/MS).
Why use multiple methods?
Targeted tests (like LC-MS/MS) are crucial for confirming known PFAS levels.
Broad-spectrum approaches (like NTA or TOP) help uncover hidden threats and give a fuller contamination profile.
The determination of PFAS is not an easy task. The sheer number of different compounds that exist can make it difficult for analytical scientists to develop tests that confidently quantify the total amount of PFAS in any given sample. Additionally, the complexity of the samples that need to be tested can add another layer of difficulty when it comes to analysis – soils, foodstuffs and other matrices often require unique analytical approaches (see our brief summary on "Typical Challenges for PFAS Analysis" ).
Michael Sperling
Related publications (newest first))
Ifeoluwa Grace Idowu, Okon Dominic Ekpe, David Megson, Pennante Bruce-Vanderpuije, Courtney D. Sandau, A systematic review of methods for the analysis of total per- and polyfluoroalkyl substances (PFAS), Sci. Total Environ., 967 (2025) 178644. DOI: 10.1016/j.scitotenv.2025.178644
Zahra Zahra, Minkyung Song, Zunaira Habib, Sadaf Ikram, Advances in per- and polyfluoroalkyl substances (PFAS) detection and removal techniques from drinking water, their limitations, and future outlooks, Emerging Contaminants 11 (2025) 100434. DOI: 10.1016/j.emcon.2024.100434
Dorian Thompson, Niloofar Zolfigol, Zehui Xia, Yu Lei, Recent progress in per- and polyfluoroalkyl substances (PFAS) sensing: A critical mini-review, Sensors and Actuators Reports, 7 (2024) 100189. DOI: 10.1016/j.snr.2024.100189
Dilani Perera, Wesley Scott, Rachel Smolinski, Leenia Mukhopadhyay, Carrie A. McDonough, Techniques to characterize PFAS burden in biological samples: Recent insights and remaining challenges, Trends Environ. Anal. Chem., 41 (2024) e00224. DOI: 10.1016/j.teac.2023.e00224
Abd Ur Rehman, Michelle Crimi, Silvana Andreescu, Current and emerging analytical techniques for the determination of PFAS in environmental samples, Trends Environ. Anal. Chem., 37 (2023) e00198. DOI: 10.1016/teac.2023.e00198
Jeffrey R. Enders, Grace M. O’Neill, Jerry L. Whitten & David C. Muddiman, Understanding the electrospray ionization response factors of per- and poly-fluoroalkyl substances (PFAS), Anal. Bioanal. Cem., 414 (2022) 1227-1234. DOI: 10.1007/s00216-021-03545-8
Jeremy P. Koelmel, Paul Stelben, Carrie A. McDonough, David A. Dukes, Juan J. Aristizabal-Henao, Sara L. Nason, Yang Li, Sandi Sternberg, Elizabeth Lin, Manfred Beckmann, Antony J. Williams, John Draper, Jasen P. Finch, Jens K. Munk, Chris Deigl, Emma E Rennie, John A. Bowden & Krystal J. Godri Pollitt, FluoroMatch 2.0—making automated and comprehensive non-targeted PFAS annotation a reality, Anal. Bioanal. Chem., 414 (2022) 1201-1215. DOI: 10.1007/s00216-021-03392-7
Shenglan Jia, Mauricius Marques Dos Santos, Caixia Li & Shane A. Snyder, Recent advances in mass spectrometry analytical techniques for per- and polyfluoroalkyl substances (PFAS), Anal. Bioanal. Cem., 414 (2022) 2795-2807. DOI: 10.1007/s00216-022-03905-y
Shenglan Jia, Mauricius Marques Dos Santos, Caixia Li, Shane A. Snyder, Recent advances in mass spectrometry analytical techniques for per- and polyfluoroalkyl substances (PFAS), Anal. Bioanal. Chem., 414 (2022) 2795-2807. DOI: 10.1007/s00216-022-03905-y
R. Aro, U. Eriksson, A. Kärrman, I. Reber, L.M.Y. Yeung. 2021. Combustion ion chromatography for extractable organofluorine analysis; iScience, 24/9 (2021) 102968. DOI: 10.1016/j.isci.2021.102968
D. Camdzic, R.A. Dickman, D.S. Aga. 2021. Total and class - specific analysis of per - and polyfluoroalkyl substances in environmental samples using nuclear magnetic resonancespectroscopy. J. Hazard. Mater. Lett., 2 (2021) 100023. DOI: 10.1016/j.hazl.2021.100023
Shoji F. Nakayama, Mitsuha Yoshikane, Yu Onoda, Yukiko Nishihama, Miyuki Iwai-Shimada, Mai Takagi, Yayoi Kobayashi, Tomohiko Isobe, Worldwide trends in tracing poly- and perfluoroalkyl substances (PFAS) in the environment, Trends Anal. Chem., 121 (2019) 115410. DOI: 10.1016/j.trac.2019.02.011
Yan-na Liu, Lisa A. D'Agostino, Guangbo Qu, Guibin Jiang, Jonathan W. Martin, High-resolution mass spectrometry (HRMS) methods for nontarget discovery and characterization of poly- and per-fluoroalkyl substances (PFASs) in environmental and human samples, Trends Anal. Chem., 121 (2019) 115420. DOI: 10.1016/j.trac.2019.02.021
N.L. Azua Jamari, J.F. Dohmann, A. Raab, E.M. Krupp, J. Feldmann, Novel
non-targeted analysis of perfluorinated compounds using
fluorine-specific detection regardless of their ionisability
(HPLC-ICPMS/MS - ESI-MS), Anal. Chim. Acta, 1053 (2019) 22-31. DOI: 10.1016/j.aca.2018.11.037
E.E. Ritter, M.E. Dickinson, J.P. Harron, D.M. Lunderberg, P.A. DeYoung, A.E. Robel, J.A. Field, G.F. Peaslee. PIGE as a screening tool for Per - and polyfluorinated substances in paper s and textiles. Nucl. Instrum.Methods Phys. Res. Sect. B., 407 (2017) 47 - 54. DOI: 10.1016/j.nimb.2017.05.052
Annika Jahnke, Urs Berger, Trace analysis of per- and polyfluorinated alkyl substances in various matrices—How do current methods perform?, J. Chromatogr. A, 1216/3 (2009) 410-421. DOI: 10.1016/j.chroma.2008.08.098
Ifeoluwa Grace Idowu, Okon Dominic Ekpe, David Megson, Pennante Bruce-Vanderpuije, Courtney D. Sandau, A systematic review of methods for the analysis of total per- and polyfluoroalkyl substances (PFAS), Sci. Total Environ., 967 (2025) 178644. 
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