Analytical Solutions for PFAS Testing

Significance of the Topic

Per- and polyfluoroalkyl substances (PFAS) are a large, chemically diverse class of persistent fluorinated organics used since the 1950s across industrial and consumer applications. Their extreme chemical and thermal stability generates environmental persistence, bioaccumulation and widespread human exposure via water, food, air and consumer products. As regulatory limits for PFAS in drinking water and food become more stringent, analytical laboratories require sensitive, robust and high-throughput methods that can meet multiple standardized methods (EPA, ISO, ASTM, AOAC) and support both routine compliance testing and broader discovery work to detect unknown species.

Study Objectives and Overview

This technical overview presents a portfolio of chromatography and mass spectrometry solutions for PFAS analysis across matrices: drinking water, wastewater, soil, tissue, ambient air, foodstuffs, packaging, textiles and consumer products. Objectives include demonstrating method performance against regulatory and consensus methods (EPA 533/537.1/544/545/1633A, ISO 21675, ASTM D8421, AOAC SMPR), illustrating high-sensitivity direct-injection workflows, offering high-throughput sample routes, and showing untargeted high-resolution screening capabilities for suspect/unknown PFAS.

Methodology and Workflow Summary

Key methodological approaches described:

• Targeted LC-MS/MS (triple quadrupole) for regulatory compliance and routine quantitation of suites of PFAS across water, wastewater, food and tissue matrices, following EPA, ISO, ASTM and AOAC procedures.
• Ultra-high-sensitivity direct injection LC-MS/MS to quantify low-ng/L PFAS in drinking water without solid-phase extraction, reducing sample preparation time.
• High-throughput LC-MS/MS methods with automatic method switching to alternate between PFAS and cyanotoxin assays on the same platform while controlling carryover via delay columns and rinse sequences.
• Solid-phase extraction (SPE) and QuEChERS-based sample preparation for complex food matrices with options for on-line SPE (stacked injection) to increase sensitivity and throughput.
• Combustion ion chromatography (CIC) analysis of Adsorbable Organic Fluorine (AOF) as a sum-parameter screen to capture total organic fluorine including non-target PFAS not observed by chromatographic methods (EPA Method 1621).
• Thermal desorption GC-MS for volatile/neutral PFAS (fluorotelomer alcohols, FTACs, FOSAs) in ambient air, avoiding solvent extraction.
• High-resolution accurate mass (HRAM) LC-QTOF data-independent acquisition (DIA) workflows for untargeted/suspect screening of unknown PFAS, including mass-defect filtering and MS/MS deconvolution for library matching and structural assignment.

Used Instrumentation

Representative instrumentation and platform roles highlighted in the work:

• Triple quadrupole LC-MS systems: LCMS-8060RX, LCMS-8065XE, LCMS-8060RX — used for EPA/ISO/ASTM/AOAC targeted methods, multi-method switching, and ultra-high-sensitivity direct injection workflows.
• Single-quadrupole LC-MS: LCMS-2050 — compact, lower-cost option for screening and quantitation when sub-ppb regulatory sensitivity is not required.
• QTOF / HRAM: LCMS-9030 / LCMS-9050 — for high-resolution DIA screening and confident identification of unknown PFAS species.
• GC-MS with thermal desorption: GCMS-QP2020 NX paired with TD-30R thermal desorption system for volatile/semivolatile neutral PFAS in ambient air.
• Combustion ion chromatography: HIC-ESP IC coupled to AQF-5000H combustion unit for AOF analysis (EPA 1621).
• X-ray fluorescence: EDX-8100 EDXRF for rapid elemental fluorine screening in textiles and coatings (qualitative/semiquantitative check for potential PFAS presence).
• UHPLC front ends and automation: Nexera UHPLC systems with on-line SPE capability (stacked injection), Nexcol PFAS Delay columns to reduce background and protect analytical columns.

Main Results and Discussion

Highlights of analytical performance across matrices:

• Drinking water: LC-MS/MS workflows (EPA 537.1 / 533) achieved detection and quantitation at or below current MCL-equivalent levels; ultra‑sensitive LCMS-8065XE direct injection measured 29 PFAS at <1 ng/L with robust recoveries (80–120%) and reproducibility.
• Multi-method operation: A single triple-quadrupole system performed PFAS and cyanotoxin methods with automated method switching and effective rinses, maintaining accuracy (80–120%) and %RSDs generally <15% across runs.
• Wastewater/Non-potable water: ASTM D8421 and ISO 21675 implementations quantified 30–44 PFAS with optimized chromatographic conditions (improved early-eluting peak shapes via co-injection techniques) and met method performance criteria (70–130% recoveries, ≤30% RSD for ASTM/ISO requirements).
• Soil and tissue: LCMS-RX series demonstrated extreme robustness—500 consecutive soil injections with maintenance of peak area repeatability (RSDs ~4.8–6.8%) and QC recoveries between 80–120%; LCMS-8065XE achieved LLOQs well below EPA 1633A requirements and maintained separation of PFOS from interfering bile acids in tissue matrices.
• Food matrices: Validated AOAC-targeted methods quantified 30 PFAS in fish fillet, milk and eggs with LOQs meeting AOAC SMPR (e.g., milk PFOS/PFOA LOQs down to 0.01 µg/kg) and recoveries within acceptance ranges.
• Consumer products and packaging: Direct LC-MS/MS extraction workflows for fast-food packaging and consumer items found multiple PFAS at ng/dm2 levels (well below older Danish guideline thresholds). A straightforward extraction chemistry for solid consumer products produced surrogate recoveries 70–130% with low RSDs.
• Discovery screening: HRAM-DIA on LC-QTOF detected PFAS-like features at sub-ng/mL levels, enabling discovery of previously unmonitored PFAS species (16 PFAS-like species identified in an example water sample) through deconvoluted MS/MS and library matching.
• AOF (CIC): The CIC workflow provided automated combustion-to-IC analysis with MDL ≈1.27 µg/L fluoride-equivalent and accurate calibration across a wide dynamic range, useful as a complementary bulk-screen for total fluorine.

Practical Benefits and Applications

• Regulatory compliance: Validated LC-MS/MS methods meet or exceed multiple reference method performance criteria enabling compliance testing for drinking water, wastewater, food and tissue.
• Laboratory efficiency: Direct injection and on-line SPE reduce hands-on sample preparation and increase throughput for screening programs and emergency response (e.g., algal bloom incidents).
• Comprehensive monitoring: Combining targeted MS/MS, CIC sum-parameters and HRAM discovery covers both regulated targets and unknown or poorly characterized PFAS, supporting surveillance and remediation verification.
• Cost-effective screening: Compact single-quadrupole systems and EDXRF provide accessible screening tiers for labs with lower throughput or budgets, enabling widespread monitoring efforts.

Future Trends and Opportunities

• Method harmonization and standardization across jurisdictions will continue; instrument platforms that can adapt to evolving target lists and lower regulatory limits will be essential.
• Greater integration of HRAM untargeted screening with robust suspect libraries and automated annotation tools will expand the detectable PFAS universe and improve source apportionment.
• Automation and miniaturized sample preparation (on-line SPE, direct injection, standardized extraction kits) will further increase throughput and lower per-sample cost, aiding large-scale surveillance programs.
• Complementary techniques (CIC-AOF, EDXRF) will remain valuable for rapid screening and mass-balance assessments that flag samples for detailed chromatographic characterization.
• Advances in ion source design, collision cell efficiency and background-reduction columns (PFAS delay columns) will improve sensitivity while reducing instrument downtime and background contamination risks.

Conclusion

A tiered analytical strategy—combining sensitive targeted LC-MS/MS methods, robust sample preparation (including on-line SPE or simplified extraction), CIC sum-parameter screening, GC-MS for volatiles, and HRAM discovery—provides comprehensive coverage for PFAS monitoring across environmental and consumer matrices. Instrumental advances demonstrated here deliver the sensitivity, robustness and throughput necessary to meet current regulatory needs and to adapt to expanding target lists and lower reporting limits.

References

• U.S. EPA Method 537.1: Determination of Selected Per- and Polyfluorinated Alkyl Substances in Drinking Water by SPE and LC-MS/MS.
• U.S. EPA Method 533: Determination of Per- and Polyfluoroalkyl Substances in Drinking Water by SPE and LC-MS/MS.
• U.S. EPA Methods 544 and 545: Methods for Cyanotoxins in Drinking Water (LC-MS/MS).
• U.S. EPA Method 1621: Adsorbable Organic Fluorine (AOF) in Aqueous Matrices by Granular Activated Carbon Adsorption and CIC.
• U.S. EPA Method 1633 / 1633A: Determination of Per- and Polyfluoroalkyl Substances in Aqueous and Solid Matrices by LC-MS/MS.
• ISO 21675: Determination of Per- and Polyfluoroalkyl Substances in Water (standardized method including long-chain PFAS).
• ASTM D8421-22: Standard Practice for Determination of PFAS in Non-Potable Water by LC-MS/MS.
• AOAC SMPR for PFAS in Food Matrices: Standard method performance requirements for targeted PFAS analysis in foodstuffs.
• Shimadzu application notes and instrument documentation (LCMS, QTOF, GCMS, CIC, EDXRF) summarizing platform-specific implementations and performance demonstrations.