Written by

Julien Guidici

Table of contents

PFAS Testing and the Hidden Risk of Liner Contamination
Why Liner Contamination Matters in PFAS Testing
How Liner Materials Influence PFAS Test Results
Emerging Best Practices for PFAS-Free Liner Selection
Cleaner Packaging for Ultra-Trace PFAS Workflows

Mitigating Liner Risks to Protect PFAS Testing Integrity

Article contributed by

Julien Guidici

Ned Burnett

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PFAS Testing and the Hidden Risk of Liner Contamination

In recent years, the demand for ultra-trace PFAS (Per- and Polyfluoroalkyl Substances) testing has grown rapidly. Regulatory bodies around the world are setting stricter limits on PFAS in drinking water, food packaging, and environmental samples. This has pushed laboratories to adopt highly sensitive analytical workflows designed to detect contaminants at parts-per-trillion or even parts-per-quadrillion levels.

While most labs focus heavily on instrument calibration and sample preparation protocols, one critical contamination risk is often overlooked. The materials used in vial closures and container liners can introduce PFAS into samples, undermining test accuracy and requiring costly retesting.

Why Liner Contamination Matters in PFAS Testing

Many common liner materials used in diagnostic and laboratory packaging contain fluorinated compounds. PTFE (Polytetrafluoroethylene) is one of the most widely used materials in vial liners because of its chemical inertness and low extractables profile. However, PTFE is part of the broader family of fluoropolymers, which are chemically linked to PFAS.

When these materials are used in sample vials, there is a risk that trace levels of PFAS compounds can leach from the liner into the sample, particularly during extended storage, solvent contact, or thermal exposure. For ultra-trace testing, even nanogram or picogram quantities of background PFAS contamination can distort results.

In addition to direct leaching, PTFE and other fluoropolymer liners may also release microscopic particles or residues that can show up in LC-MS/MS and other high-sensitivity detection methods.

How Liner Materials Influence PFAS Test Results

Liner-related contamination can affect PFAS testing in several ways:

False positives from background PFAS compounds present in the liner material
Elevated baseline signals that reduce method sensitivity
Increased measurement variability and poor reproducibility
The need to rerun samples, leading to higher costs and longer turnaround times
Risk of non-compliance with regulatory reporting requirements

For laboratories tasked with meeting strict detection limits, these risks can be significant.

Emerging Best Practices for PFAS-Free Liner Selection

As awareness of liner contamination risks grows, laboratories and packaging manufacturers are taking proactive steps to reduce background PFAS interference.

Key strategies include:

1. Switching to PFAS-Free Liner Materials

Polypropylene (PP) and other polyolefin-based liners provide strong chemical compatibility without introducing fluorinated compounds. These materials are becoming preferred options for PFAS analysis workflows.
Using Single-Material Closures

Whenever possible, single-material caps and liners reduce the complexity of the closure system and minimize potential contamination sources.
3. Eliminating Adhesives and Chemical Binders

Ultrasonic welding or mechanical press fit liner assembly eliminates the need for adhesives, which may contain extractable fluorochemicals.
4. Conducting Liner Background Testing

Leading laboratories now include liner and closure background screening in their quality assurance protocols to ensure packaging components do not introduce PFAS contamination.

Cleaner Packaging for Ultra-Trace PFAS Workflows

The shift toward PFAS-Free* liner solutions is part of a broader effort to improve the sustainability and safety of laboratory and diagnostic packaging. As global regulations continue to tighten and PFAS detection limits become more stringent, laboratories are recognizing that contamination control must extend beyond sample preparation and instrumentation. It must include the materials used in the entire analytical workflow.

Packaging manufacturers are responding by developing PFAS-free liner options designed specifically for ultra-trace testing environments. These new solutions balance chemical compatibility, sealing performance, and regulatory compliance while supporting laboratories' efforts to produce reliable and accurate results.

Mitigating Liner Risks to Protect PFAS Testing Integrity

PFAS testing requires an extraordinary level of sensitivity and precision. When working at the parts-per-trillion level, even the smallest sources of contamination can compromise results. Vial liners and cap materials, once considered an afterthought, are now recognized as a critical control point in PFAS analysis workflows.

For laboratories and manufacturers committed to quality and compliance, when choosing the right liner material, understanding and addressing the hidden risks of liner contamination is essential to delivering accurate, defensible data.

*PFAS-Free here means we do not intentionally add PFAS material in the product, but does not exclude the possibility of traces, as these materials are common in the environment. This statement is valid unless superseded by a revised statement at a later date.

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