The case for bringing your PFAS testing in-house

As the regulatory landscape for PFAS evolves in the US and across the globe, interest in PFAS continues to grow. Drinking water and food packaging are under particular scrutiny, and monitoring programs and requirements will continue to expand to include an increasing variety of sample types and PFAS compounds.

Organizations that must adhere to these regulatory demands will be under increasing pressure to control costs as sample testing volumes increase. Acquiring high-quality instrumentation and PFAS analysis training to enable in-house testing is a potentially valuable cost-containment approach for any labs that require ongoing PFAS testing. Here, I have outlined some key considerations to help you decide whether to bring PFAS testing in-house.

Cost

The cost of third-party analysis can quickly add up to several hundred dollars per sample, especially in resampling cases caused by contamination. As your testing needs grow, increased testing volume and complexity will raise the costs of your testing program. Acquiring your own instrumentation along with highly specialized PFAS-focused training from SCIEX will allow you to control testing costs as your test volume and complexity increase.

Turnaround time (TAT)

Timely PFAS testing results are needed to make quick decisions about the treatment and mitigation of PFAS contamination to meet regulatory requirements and protect public health. Rapid turnaround times within 24 hours, if they are commercially available at all, are cost-prohibitive in most situations. With in-house instrumentation, turnaround times of less than 24 hours can be achieved at a lower cost using fewer resources.

Quality assurance (QA) and quality control (QC)

Testing PFAS samples in-house provides greater visibility into the entire process for your whole QA/QC system and for troubleshooting difficult samples. SCIEX can help you develop robust and highly accurate methods and automate your PFAS analysis protocol from sample preparation through data reporting. This can further increase the precision of your results and help you consistently meet QA/QC requirements.

Method flexibility

PFAS contamination investigations sometimes require creative and flexible sampling and analysis protocols to track sources of contamination. This could involve performing swabs of potentially contaminated sampling environments for source tracking, performing serial dilutions of heavily contaminated samples and using direct injection dilute-and-shoot methods for rapid screening of large numbers of samples. It could also involve confirming positive identifications with full-scan methods or screening for novel PFAS that are not available at commercial testing labs.

Avoiding cross-contamination when analyzing PFAS samples

Collecting and analyzing PFAS samples requires special care as there is a high risk of cross-contamination from sources such as clothing worn in the field, sample bottles and laboratory consumables and equipment used during sample preparation. This means you must take extra care to attain both accuracy and precision when extracting PFAS from samples. When it comes to both short-chain and long-chain PFAS extraction from drinking water, the choice of method—solid-phase extraction (SPE) or direct injection—depends on the regulatory requirements that must be addressed.

Solid-phase extraction (SPE)

US EPA Method 533 and Method 537.1 require water samples to be concentrated using SPE cartridges. A weak-anion exchange SPE is typically used and 100–250 mL of water is concentrated to 1 mL.

Mean accuracy (primary y-axis, bars) and CV% (secondary y-axis, lines) of 0.50 ng/mL and 25 ng/mL standards (n =5).

SPE has several advantages for measuring PFAS in water. First, the 100–250x concentration step allows for very low parts-per-trillion "in sample" detection limits. This low detection limit ensures the highest degree of protection for human health and the environment. Second, during the SPE process, unwanted interferences are either unretained or rinsed from the cartridge. This results in a "clean" sample extract to help maintain instrument robustness—and thus high sample throughput— and unambiguous quantification. Third, SPE is rigorous and reproducible, which helps ensure good data quality.

Direct injection

There are also certain regulatory guidelines or methods that adopt a direct injection approach for fast screening that requires relatively high reporting limits. The EU Drinking Water Directive 2020/2184 and US EPA Method 8327 are examples of regulations with this requirement.

The direct injection approach requires minimal sample preparation and overall fewer steps, so there are fewer chances for analyte loss or labbased PFAS contamination. In addition, the sample preparation time is much lower, resulting in higher sample throughput.

Overlaid multiple reaction monitoring (MRM) traces of PFAS detected in a groundwater sample with the calculated concentrations of each PFAS.

Learn more about using SPE and direct injection for PFAS analysis in the PFAS eBook from SCIEX

Both the SPE and direct injection approaches can be expanded beyond testing for PFAS in water to include testing in soil, sediment and biological extract. With the growing need for PFAS analysis of environmental samples, these versatile methods will be useful for labs aiming to evaluate growing lists of PFAS.