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Section 4

The Science of Detecting PFAS

How Sampling and Analysis Shape the Fight Against Forever Chemicals

Section 4

The Science of Detecting PFAS: How Sampling and Analysis Shape the Fight Against Forever Chemicals

Understanding the Importance of Accurate PFAS Detection

Per- and polyfluoroalkyl substances (PFAS) have become one of the most complex environmental challenges of our generation. These persistent “forever chemicals” are used in thousands of consumer and industrial products, and their resistance to degradation means they’re now found in water, soil, sediment, air, and even wildlife.

But knowing PFAS are everywhere is only the first step. Detecting and quantifying them accurately is what enables scientists, regulators, and industries to manage contamination effectively.

Because PFAS can exist at trace concentrations — sometimes just a few parts per trillion — even minor sampling errors or contaminated equipment can lead to misleading results. As a result, the global environmental community is refining both sampling protocols and analytical chemistry techniques to achieve reliable detection across hundreds of PFAS variants.

The Challenge of PFAS Sampling

PFAS sampling is not as simple as collecting a water or soil sample. These compounds are so widespread that cross-contamination is a constant threat. Materials commonly used in fieldwork — gloves, tubing, containers, or even waterproof clothing — can contain PFAS and interfere with results.

Best Practices for PFAS Sampling [1]

Environmental experts recommend rigorous field controls and specialized procedures, including:

PFAS-free sampling equipment: Avoid fluoropolymer or Teflon materials; use high-density polyethylene (HDPE) or polypropylene instead.
Field Quality Assurance/Quality Control (QA/QC): Use blanks (trip, field, and equipment) to detect any external contamination.
Low-flow sampling techniques: Collect groundwater slowly to minimize disturbance and avoid drawing in particulate matter that could skew PFAS levels.
Temperature control: Keep all samples chilled immediately after collection and transport them on ice.
Documentation: Record every field procedure, including potential contamination sources, sample handling, and environmental conditions.

Even the smallest oversight — a piece of tape, a permanent marker, or a treated paper towel — can introduce false positives. That’s why PFAS sampling requires a meticulous, contamination-aware mindset throughout the entire process.

Analytical Methods: How PFAS Are Measured in the Lab [2]

Once samples reach the laboratory, they undergo advanced analytical testing designed to detect trace PFAS concentrations with extreme precision. The complexity lies in the diversity of PFAS — there are over 10,000 known compounds [3], each with different molecular structures and chemical behaviors.

The following are the most widely used laboratory methods in PFAS analysis today:

1. Targeted Analysis: LC-MS/MS (Liquid Chromatography–Tandem Mass Spectrometry)

This is the gold standard for PFAS quantification. LC-MS/MS separates PFAS molecules from the sample and identifies them by their unique mass-to-charge ratios.

Advantages: Extremely specific, can identify and measure individual PFAS such as PFOS, PFOA, PFHxS, and PFNA with high accuracy.
Limitations: Only detects PFAS that are explicitly targeted in the test method; cannot measure unknown or emerging PFAS.

2. TOP Assay (Total Oxidizable Precursor Assay)

The TOP assay provides insight into precursor compounds — PFAS that may not be detectable initially but can transform into persistent PFAS through oxidation.

Advantages: Offers a better picture of total PFAS potential.
Limitations: Results are semi-quantitative; not all precursors convert under lab conditions.

3. EOF and TOF Analysis (Extractable or Total Organic Fluorine)

These broad-spectrum tests measure total fluorine content in a sample, offering a high-level overview of PFAS contamination.

Advantages: Detects both known and unknown PFAS; valuable for screening.
Limitations: Non-specific; does not differentiate between PFAS and other organofluorine compounds.

4. Combining Methods for Comprehensive Results

Because no single method provides the full picture, many laboratories use a tiered analytical approach, combining targeted LC-MS/MS with TOP and EOF/TOF testing. This hybrid strategy allows investigators to capture both known and emerging PFAS and track how they behave under environmental conditions.

Quality Control and Data Validation

To ensure data reliability, strict quality control (QC) is applied at every stage of PFAS analysis. This includes:

Laboratory blanks to detect contamination within analytical systems.
Duplicate samples to confirm consistency.
Matrix spikes to assess analytical recovery.
Method detection limits (MDLs) and quantification limits (QLs) clearly reported for transparency.

Modern laboratories are also adopting ISO 17025 accreditation for PFAS analysis, ensuring that all testing adheres to internationally recognized quality standards.

Emerging Technologies in PFAS Detection

As PFAS regulation tightens and the list of monitored compounds expands, new high-resolution analytical technologies are gaining attention. These include:

High-Resolution Mass Spectrometry (HRMS): Provides ultra-precise identification of emerging or novel PFAS compounds.
Time-of-Flight (TOF) and Orbitrap instruments: Capable of untargeted screening to discover unknown PFAS structures.
Portable field-based detection systems: Promising for rapid, on-site PFAS screening, though still in early development.

These advances are crucial as regulators shift from targeting a few well-known PFAS (like PFOA and PFOS) to addressing the entire chemical class.

Why PFAS Data Integrity Matters

Accurate data isn’t just a technical requirement — it’s the foundation of responsible decision-making. Governments rely on PFAS measurement data to set drinking water limits and cleanup standards. Companies depend on it to assess liability and plan remediation. And communities use it to advocate for clean, safe environments.

Errors or inconsistencies in sampling or analysis can lead to misguided policy, costly mismanagement, or false reassurance. Reliable PFAS data, by contrast, enables targeted cleanup, effective regulation, and scientific innovation.

Building a Robust PFAS Monitoring and Management Plan

For organisations managing contaminated land or industrial assets, a proactive PFAS monitoring strategy should include:

Baseline assessments to establish existing contamination levels.
Ongoing monitoring programs for soil, groundwater, and wastewater.
Integration of multiple analytical methods to detect both known and emerging PFAS.
Data transparency with regulators and stakeholders.
Periodic review and technology updates as new PFAS detection methods evolve.

This approach not only ensures regulatory compliance but also strengthens sustainability credentials and investor confidence.

Conclusion: Precision and Persistence in the Fight Against PFAS

Detecting PFAS isn’t just about advanced chemistry — it’s about persistence, precision, and trust. With contamination now recognized across the globe, accurate sampling and analytical science form the cornerstone of any successful PFAS response.

As technology evolves, the world is moving closer to identifying — and eventually eliminating — the invisible threat posed by forever chemicals. Whether you’re an environmental professional, a regulator, or a business owner, understanding PFAS detection science is the first step toward a cleaner, safer future.

Updated: 8 December 2025

Section bibliography

[1] https://pfas-1.itrcweb.org/wp-content/uploads/2022/09/Sampling_and_Lab_PFAS_Fact-Sheet_082522_508.pdf

[2] https://doi.org/10.1016/j.scitotenv.2025.178644

[3] https://echa.europa.eu/-/echa-publishes-pfas-restriction-proposal