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Meet regulatory limits: Characterize and quantify PFAS and GenX in water using liquid chromatography-mass spectrometry

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Per- and polyfluorinated alkyl substances (PFAS) continue to persist throughout the environment.Concerns about the health dangers posed by these contaminants, along with the possibility of biological toxicity of legacy PFAS such as perfluorooctanoic acid (PFOA) and perfluorooctanoic sulfonic acid (PFOS), have led to the production of PFAS alternatives.1 Such alternatives include hexafluoropropylene oxide-dimer acid (HFPO-DA), commonly referred to as GenX.

I covered the what’s and whys of PFAS contamination in my last post. This time let’s explore some of the existing regulatory guidelines to handle these resilient contaminants. I’d also like to look at how the triple quadrupole and linear ion trap mass spectrometers can help you characterize and quantify the presence of PFAS and GenX in water to comply with those limits.

A snapshot of global regulations and guidelines

North America

There has been quite a bit of PFAS regulation in the US in recent years. In early 2019, the US Environmental Protection Agency (EPA) published the multi-pronged Per- and Polyfluoroalkyl Substances (PFAS) Action Plan. As you scroll through the plan, you’ll appreciate the extent of the task ahead. Some have criticized the strategy behind this plan for moving slowly in the face of widespread PFAS exposures. This has prompted independent action by state and regional organizations, which are now introducing their own bans and regulations.

Under the Safe Drinking Water Act (SDWA), the EPA has regulated more than 90 drinking water contaminants, setting maximum contaminant levels (MCLs) for specific chemicals in public water supplies. However, there are arguments that the health advisory levels established in this act—70 parts per trillion—are as much as 10 times too high for chemicals found in Teflon and firefighting foam.

As an analytical scientist, I was excited when the EPA introduced its new validated method for determining PFAS levels in drinking water, known as Method 533, which focuses on “short-chain” PFAS and PFAS with carbon chain lengths of 4 to 12. Using this method in combination with the EPA’s Method 537.1 can enable testing for 11 additional PFAS.

Canadahas designated several classes of chemicals as toxic substances and has prohibited its use and import. The current guideline for Canadian drinking water quality for PFOA is 0.02 ug/L and for PFOS is 0.06 ug/L.

European Union (EU)

PFOS and PFOA are both listed as persistent organic pollutants (POPs) in Annex A of theStockholm Convention, This guide advises the elimination of the production and use of the chemicals. Due to the recommendations in this guide, PFAS use and manufacture are much less in the EU than in the US. The region has been taking measures for a while now, to reduce its PFAS footprint, mainly addressing well-known PFAS substances and their precursors.

At the moment, PFOS is regulated as a POP under the Registration, Evaluation, Authorisation, and Restriction of Chemicals (REACH) law.2 In 2017, the EU classified PFOA and similar substances as Substances of Very High Concern (SVHCs) on the REACH list. GenX was added to this list due to its persistent and toxic properties when it comes to drinking water and the environment. That said, the plan is to regulate these substances in phases. Another candidate for strict regulation is perfluorobutanesulfonic acid (PFBS) along with PFOA and PFOS as priority hazardous substances under the EU’sWater Framework Directive.3-5

Australasia

In this region, Australia is leading the charge. The Industrial Chemicals (Notification and Assessment) Act 1989 regulates new PFAS and new precursor chemicals that could break down to form PFAS. Australia also enforces import and export controls on PFOS, and selected precursors are listed under the Rotterdam Convention.

New Zealand on the other hand, has prohibited the import, manufacture and use of PFOS and restricted the use of PFOA since 2011. In 2017, the Hazardous Substances and New Organisms (HSNO) Act 1996 banned the use of any non-approved Class B foam concentrates (foams that have not been tested and confirmed as free of PFOS and PFOA).

In addition, both Australia and New Zealand have collaborated to develop a PFAS National Environmental Management Plan (NEMP) to build a consistent approach to regulating the use of PFAS.

Asia and the Middle East

There is a lot of room for PFAS regulation to grow in this region. Many countries have restricted the use of PFOS in line with the Stockholm Convention, but most PFAS substances are still unregulated. Firefighting foams and extinguishers, for example, are readily available for consumer purchase in most countries in this region.

Characterize and quantify PFAS and GenX

Now that you have an overall understanding of the existing regulations let’s look at triple quadrupole and QTRAP® mass spectrometers available to help you comply with them. Whether you are a water provider, a utility company or an environmental monitoring agency, you are most likely contending with:

  • Time-intensive methods, from sample prep through data processing, often with multiple analyses per sample
  • Hundreds of diverse compounds, but with limits on the number of compounds and classes you can target per analysis
  • The need for higher sensitivity to detect low-level concentrations and meet regulatory requirements
  • High-volume, high-throughput workflows that struggle with “sticky” PFAS compounds, resulting in eroded data quality during long runs

Well, guess what? The QTRAP addresses these issues head-on. Not only can they handle high-volume, routine PFAS analyses for water samples from multiple sources, but their advanced features will also prepare any environmental testing lab for whatever the future holds.

Just to give you a picture:

  • Triple quadrupole mass spectrometers contain two quadrupole analyzers with a third that acts as a collision cell. This approach delivers low-resolution mass/charge with a good linearity range. It will ensure confidence in identification and quantification at low abundances in complex samples. In this category, SCIEX offers the SCIEX Triple Quad™ System.
  • Linear ion trap mass spectrometers push triple quadrupole mass spectrometers to their limits. SCIEX offers a unique QTRAP technology that can offer up to 100 times more full-scan sensitivity over basic triple quadrupoles for simultaneous quantification and library searching. It functions like a standard triple quadrupole LC-MS/MS and doubles as a linear ion trap (LIT). It’s ideal for routine PFAS screening.

SCIEX QTRAP technology is renowned for delivering sensitivity and selectivity with minimal sample prep, short runtimes and powerful data-processing capabilities. It’s also robust enough to keep up with demanding environmental samples, and it delivers reproducible results. When it comes to meeting the demands of routine PFAS testing, every environmental lab should consider the SCIEX Triple Quad System.

The SCIEX QTRAP series: The power behind routine environmental testing

When you bring the SCIEX QTRAP Series together with an extensive PFAS MS/MS spectral library in the business, you’ll never look back. And here’s why:

  • The QTRAP system offers vigorous, reliable and high-throughput quantification and sensitivity. It is well suited for trace detection of a wide range of potential PFAS compounds in water samples. The total sample runtime takes only 8-10 minutes with sensitivity as low as 0.08 ng/L.
  • The robust Scheduled MRM™ Algorithm and the Curved LINAC® Collision Cell design in the QTRAP system improve the quality of data to ensure fewer peaks are missed and ensure optimal sensitivity.
  • The QTRAP system includes the Turbo V™IonSource, which is unique to SCIEX instruments. Ideal for PFAS compounds, it offers enhanced sensitivity in negative ion mode to detect and quantify low-concentration analytes in challenging matrices.
  • Combine this with the verified Fluorochemical High-Resolution MS/MS Spectral Library, and you have the most comprehensive PFAS testing solution available on the market. This verified library contains over 600 high-resolution MS/MS spectra for over 250 PFAS for greater confidence in making identifications.
  • SCIEX OS Software offers sophisticated workflow and data-processing capabilities to deliver an end-to-end solution on a single platform.
  • The high sensitivity of the QTRAP system increases accuracy and reduces sample contamination by allowing a direct, large-volume injection. Hitting the required limits of detection without a sample concentration step reduces the number of instances in which a sample touches plastic or Teflon componentsand minimizes the potential for introducing background noise.

Together, these features in a platform offer you the speed, accuracy and robustness you need high-throughput, routine PFAS testing. Download your copy of the QTRAP system compendium to learn more about how the SCIEX QTRAP Series can help with your analysis.

If you’re interested in learning about analytical techniques that can help you effectively discover PFAS and their precursors, read this blog.

References

  1. Gomis M.I., Vestergren R., Borg D. and Cousins I.T. (2018). Comparing the toxic potency in vivo of long-chain perfluoroalkyl acids and fluorinated alternatives. Environ. Int 113: 1–9. doi: 10.1016/j.envint.2018.01.01.
  2. EU (2019). Regulation (EU) 2019/1021 of the European Parliament and of the Council of 20 June 2019 on persistent organic pollutants (Text with EEA relevance). OJ L 169/45.
  3. EU (2006). Regulation (EC) No 1907/2006 of the European Parliament and of the Council of 18December 2006 concerning the Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH), establishing a European Chemicals Agency, amending Directive 1999/45/EC and repealing Council Regulation (EEC) No 793/93 and Commission Regulation (EC) No 1488/94 as well as Council Directive 76/769/EEC and Commission Directives 91/155/EEC, 93/67/EEC, 93/105/EC and 2000/21/EC. OJ L 396.
  4. EC (2017). Proposal for a Directive of the European Parliament and of the Council on the quality of water intended for human consumption (recast). COD No 0332. https://ec.europa.eu/environment/water/water-drink/pdf/revised_drinking_water_directive.pdf (accessed 2 December 2019).
  5. EU (2000). Directive 2000/60/EC of the European Parliament and of the Council of 23 October 2000 establishing a framework for Community action in the field of water policy. OJ L 327.
    1. Dauchy, X. (2019). Per- and polyfluoroalkyl substances (PFASs) in drinking water: Current state of the science. Current Opinion in Environmental Science & Health 7: 8–12. doi: 10.1016/j.coesh.2018.07.004
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