A Technical Guide to PFAS Analysis – Detection and Analytical Methods

PFAS present unique analytical challenges compared to most legacy contaminants. Their chemical stability, low regulatory thresholds, and widespread historical use mean that analytical results are often scrutinized as closely as the site conditions they represent. 

As PFAS regulations continue to evolve, the reliability and defensibility of analytical data have become central to investigations, remediation strategies, and redevelopment decisions. In this environment, PFAS analysis goes beyond confirming presence or absence. Analytical results are increasingly used to demonstrate regulatory compliance and shape long-term site management strategies, elevating the importance of how data is generated and interpreted. 

A strong technical understanding of detection methods, sampling considerations, and data limitations is therefore essential for applying PFAS results in a way that supports both project objectives and regulatory expectations.

Key takeaways

• PFAS analytical methods should reflect the specific environmental matrix and regulatory conditions at each site.
• Sampling practices and lab selection have a direct impact on data quality and regulatory defensibility.
• Contextual interpretation of results is essential to support informed decisions around risk, remediation, and redevelopment.

Core components of PFAS Analytical Detection Methods

PFAS detection relies on analytical approaches that vary in scope, sensitivity, and applicability. Selecting the appropriate method depends on project goals, regulatory requirements and the environmental matrix being evaluated.

EPA Method 1633 and draft analytical methods 

EPA Method 1633 is currently the most comprehensive analytical method for PFAS detection across multiple environmental media. It uses liquid chromatography coupled with tandem mass spectrometry to quantify a broad list of PFAS compounds, including carboxylates, sulfonates and select precursor compounds.

Method performance is influenced by matrix characteristics and compound-specific behavior during extraction and analysis. Detection and reporting limits vary across the compound list, which means individual results must be evaluated relative to applicable regulatory thresholds rather than viewed in isolation.

Ongoing draft updates and supplemental guidance continue to refine key aspects of the method, including:

• Compound coverage and target analyte lists
• Quality control and validation requirements
• Reporting limits and data presentation conventions

Such refinements may impact data comparability across projects and over time, particularly when results are used to support regulatory decisions or long-term site management strategies.

Targeted vs non-targeted PFAS analysis 

• Targeted PFAS analysis: Focuses on a defined list of PFAS compounds with established analytical standards and validated reporting limits. This approach produces quantitative data that can be directly compared to regulatory criteria and applied in risk assessments, remedial investigations and compliance evaluations.
  
  
• Non-targeted PFAS analysis: Used to identify unknown, emerging or proprietary PFAS compounds that fall outside standard target lists. These methods are particularly relevant at sites with complex industrial histories or historical PFAS use, where results help inform source identification, transformation pathways and conceptual site model development.

Lab-based detection vs field screening tools

• Laboratory-based PFAS analysis: Conducted by accredited laboratories using compound-specific methods that achieve lower detection limits and incorporate formal quality assurance controls. These results form the basis for regulatory decisions, risk evaluations and remedial planning.
  
  
• Field screening tools: Designed to provide rapid, screening-level indications of potential PFAS presence without compound-specific resolution. These tools can support preliminary investigations or sampling prioritization, but results must be confirmed through laboratory analysis before being used in regulatory or remedial contexts.

Detection limits and PFAS compounds typically identified

Achievable detection limits depend on the analytical method, laboratory instrumentation and sample matrix. Testing of drinking water typically achieves lower reporting limits due to reduced matrix interference, while soil and biosolids analyses often exhibit higher variability during extraction and quantification.

Commonly reported PFAS compounds include:

• PFOA
• PFOS
• PFHxS
• PFNA

These compounds reflect both historical use patterns and current regulatory focus. As analytical compound lists expand, detection of additional PFAS species can influence how contamination is characterized and how long-term site management strategies are developed.

Sampling and data quality considerations for a complete PFAS analysis 

Sampling practices are a primary driver of PFAS data quality and defensibility. Because PFAS are present in many common materials, errors introduced during sampling can be difficult to identify once laboratory analysis is complete. Analytical rigor therefore begins in the field, where consistent protocols and material controls are essential.

Sampling protocols to avoid cross-contamination

PFAS are widely used in consumer and industrial products, which increases the risk of inadvertent contamination during sampling activities. Field protocols must clearly define acceptable materials, equipment handling procedures and decontamination practices.

For example, certain waterproof fabrics, sampling containers or food packaging materials can introduce PFAS into environmental samples. Sampling plans should explicitly identify prohibited materials and document field controls so that analytical results can be defended during regulatory review.

Matrix challenges (soil, groundwater, drinking water, and biosolids)

Each environmental matrix presents unique analytical challenges that affect detection limits and data interpretation. Groundwater samples often require ultra-low reporting limits to meet drinking water criteria, which places greater demands on laboratory sensitivity and quality control.

Soil and biosolids samples can interfere with extraction and analysis, leading to increased variability and uncertainty. These matrix-specific limitations influence sample preparation requirements, achievable detection limits, and how results should be interpreted within the broader site context.

Holding times, containers, and equipment restrictions 

PFAS sampling requires strict adherence to method-specific holding times and container requirements to preserve sample integrity. Certain plastics, coatings and preservatives are restricted because they may contain or leach PFAS.

Equipment selection and handling procedures must align with analytical method requirements. Deviations can result in data qualification or rejection, which may delay investigations or require resampling.

Data usability, precision, bias, and uncertainty

Analytical results must be evaluated for usability before being applied to site characterization or risk assessment. Precision and bias are assessed through laboratory quality control samples, while overall uncertainty reflects method limitations, matrix effects, and sample handling conditions.
Understanding these factors allows practitioners to determine whether results support regulatory conclusions or whether additional investigation is necessary to reduce uncertainty.

Challenges and limitations in PFAS detection

Even with established analytical methods, PFAS detection presents inherent challenges that affect data interpretation. Recognizing these limitations is essential when applying results to risk evaluations, remediation planning, or redevelopment decisions.

Variability in lab performance and method uncertainty 

Laboratory performance can vary due to differences in instrumentation, analytical experience and quality assurance programs. Method uncertainty increases at lower concentration ranges, particularly near reporting limits.
When results are compared across laboratories or analytical methods, differences in performance and uncertainty must be considered to avoid unsupported conclusions.

PFAS mixtures and precursors that are difficult to detect

PFAS contamination often consists of mixtures that include precursor compounds not fully captured by targeted analytical methods. These precursors can transform into regulated compounds over time, altering site conditions.

Additional analytical approaches may be required to evaluate total PFAS presence and long-term behavior.

Regulatory implications of low detection limits 

As regulatory thresholds decrease, analytical variability becomes more consequential. Concentrations previously considered insignificant may now trigger compliance obligations or additional investigation.

This dynamic increases the importance of method selection, quality control documentation, and data defensibility.

Data interpretation challenges for risk and remediation

PFAS concentrations must be evaluated in the context of exposure pathways, toxicological criteria, and site-specific conditions. Analytical results alone do not define risk.

Integrating PFAS data into broader site models supports more accurate and defensible remediation planning.

PFAS analysis in site investigations and redevelopment

PFAS analytical data plays a critical role in both technical site evaluations and redevelopment planning. Incorporating this analysis early in the process helps reduce uncertainty and supports more efficient project execution.

Using analytical results to refine conceptual site models

PFAS data helps clarify the spatial distribution of compounds across soil, groundwater, and other environmental media, which is essential for building accurate conceptual site models. Patterns in concentration gradients, compound profiles, and detection frequencies can point to likely source areas and migration pathways. 

In some cases, differences in PFAS composition between sampling locations may reveal distinct release mechanisms or historical uses, prompting further delineation or targeted investigation to better define the extent and origin of impacts.

Informing risk assessment and remediation plans

Analytical results are evaluated against regulatory criteria to determine whether exposure pathways are complete and if remedial action is warranted. This data informs the development of risk assessments and guides the selection of remediation strategies by identifying affected media, the range of contaminant concentrations, and any compound-specific considerations.

Where uncertainty exists, more conservative assumptions may be required, which can influence cleanup objectives, remedy selection, and the scope of long-term monitoring.

Impact on redevelopment, permitting, and liability

PFAS findings can significantly influence the trajectory of redevelopment projects, particularly when it comes to permitting, liability assessments, and site classification. Analytical results may trigger the need for institutional controls or alter the level of regulatory involvement during project review. 

When PFAS considerations are incorporated early in the planning phase, teams can proactively address these challenges alongside design and permitting decisions, helping to avoid costly delays and last-minute changes later in the process.

Regulatory landscape for PFAS analytical methods 

The regulatory landscape for PFAS analysis is evolving quickly as detection capabilities improve and standards advance. The EPA plays a central role, driving method development and updating approved testing protocols.

EPA Method 1633 is becoming a common reference across federal and state programs, but implementation varies. Some agencies adopt it directly, while others add requirements around compound lists, detection limits, or quality control. Understanding how Method 1633 is applied locally is key to aligning sampling and analysis with regulatory expectations.

State-level rules add further complexity. Some states mandate specific methods, lower thresholds, or enforce PFAS standards ahead of federal action. These differences influence sampling design, lab selection, and project timelines—particularly for sites under multi-agency oversight.

As regulations shift, sampling plans must stay adaptable. Method updates or changing thresholds may require revisions to frequency, analyte scope, or QA protocols.

How Langan supports PFAS sampling, analysis, and data interpretation 

Langan applies a strategic, risk-informed approach to PFAS sampling, developing programs that align with site conditions, regulatory expectations, and project objectives. Each plan is designed to account for factors like matrix interferences, cross-contamination risks, and analytical uncertainty, ensuring that the data generated is both defensible and decision-ready. Method selection and laboratory coordination are tailored to support accurate, actionable results from the start.

PFAS data is interpreted within the full context of site redevelopment and regulatory requirements. Rather than treating results as standalone findings, Langan integrates them into broader risk and planning frameworks that consider exposure pathways, future site use, and long-term stewardship. This ensures that PFAS considerations are addressed proactively, helping to reduce delays, support permitting, and keep complex projects moving forward with confidence.

Contact Langan to explore PFAS sampling and analytical strategies that support informed decision-making and align project objectives.

PFAS analysis FAQs 

How are PFAS analyzed?

• PFAS are analyzed using laboratory-based methods such as EPA Method 1633, as well as drinking water–specific methods and supplemental screening approaches, all of which rely on advanced chromatography and mass spectrometry to identify and quantify compounds based on project and regulatory needs.

What are the most used analytical methods for PFAS?

• EPA Method 1633 is the most widely used method for multi-matrix analysis, while drinking water programs may reference additional EPA-approved methods.

How accurate are current PFAS detection methods?

• Accuracy depends on method selection, laboratory performance, and sample quality. Results near detection limits carry higher uncertainty and require careful interpretation.

What challenges affect PFAS sampling reliability?

• Cross-contamination risks, matrix interference, and improper materials can compromise samples if protocols are not strictly followed.

How do PFAS analytical results influence site cleanup decisions?

• Results determine whether remediation is required, which technologies are appropriate, and how cleanup goals are established. Data quality directly affects these decisions.