Why You Should be Using a Delay Column for PFAS Analysis

Posted by Chrom Tech on 14th Oct 2025

Why You Should be Using a Delay Column for PFAS Analysis

PFAS in the Environment Today

Poly- and perfluoroalkyl substances (PFAS)—commonly referred to as “forever chemicals”—have become a growing global concern due to their persistence and widespread presence in the environment. Found in everything from firefighting foams to consumer products, PFAS compounds resist natural degradation, making them a major analytical focus in water, soil, and biological testing. As environmental regulations tighten worldwide, accurate and reproducible PFAS analysis has become critical for laboratories ensuring compliance and protecting public health.

Eliminating PFAS Interference in LC Systems

Most PFAS analyses are performed using liquid chromatography–mass spectrometry (LC-MS). However, one of the greatest challenges with PFAS analysis is avoiding background contamination—especially since many LC components (such as pump seals, tubing, and valve materials) can contain fluoropolymers. Even trace contamination can compromise results, leading to false positives or inconsistent quantitation.

Although labs can take steps to reduce PFAS background interference, eliminating it entirely from the system is nearly impossible. This is where Chrom Tech’s PFAS Delay Column becomes essential.

The delay column is installed in the mobile phase flow path just before the injector. Its function is to “trap” or delay background PFAS compounds originating from LC system components before they reach the analytical column (see diagram below). During sample injection, only PFAS compounds from the sample itself are retained at the head of the analytical column and subsequently eluted during the gradient run. Background PFAS retained by the delay column elute later, effectively separating system-based interference from target analytes.

PFAS delay column diagram

Preventing PFAS Contamination in Samples

Beyond instrumentation, sample handling plays a significant role in minimizing contamination. PFAS can leach from PTFE-lined caps and vials, introducing background interference during analysis. To eliminate this risk, laboratories should use PTFE-free vials and closures.

Chrom Tech offers fully PFAS-safe options such as the PTFE-free Snap Seal Vial and the compatible PTFE-free Closure. These components are designed to ensure sample integrity from collection through injection, helping labs achieve lower background levels and cleaner chromatograms.

If you have questions about PFAS testing methods or need help configuring your LC-MS system for PFAS analysis, our technical specialists are available at support@chromtech.com to provide guidance and recommend compatible PFAS-free products.

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Frequently Asked Questions About PFAS Analysis

Why is PFAS analysis so challenging?

PFAS compounds are extremely persistent and present in many laboratory materials, including LC tubing, seals, and vials. This makes background contamination common and difficult to eliminate without specialized equipment and PFAS-free consumables.

What is the purpose of a PFAS delay column?

A PFAS delay column traps system-based PFAS contaminants before they reach the analytical column, separating background compounds from analytes of interest. This improves data accuracy and reduces interference in LC-MS results.

How can I minimize PFAS contamination in samples?

Use PTFE-free consumables, including vials, caps, and septa. Chrom Tech’s PTFE-free Snap Seal Vials and Closures are ideal for PFAS testing applications.

Does Chrom Tech offer PFAS-free LC products?

Yes. Chrom Tech supplies a complete range of PFAS-free LC consumables, including delay columns, solvent-safe tubing, and vials, to help laboratories maintain clean baselines and meet regulatory testing standards.