Environmental Laboratory - Focus on PFAS Analysis 35
which is selected especially for water-contaminated samples, within 77 min. Thus, the two devices can be ideally combined in the laboratory and one can realise a workfl ow for a high sample- throughput.
Conclusion
The analytical objectives of the applied method were met with good recoveries and very low standard deviations without cross-contamination, due to reliable and robust automation. Similarly, the analytical objectives of the DIN method were also met with high selectivity, trueness and precision. The use of the automated D-EVA vacuum centrifuge, which allows unattended parallel concentration of the collected PFAS eluate, enables gentle concentration, which achieves particularly high robustness.
Fig. 2: Comparison of recovery rates
content in the eluate is sometimes impossible to avoid, which represents a further challenge for concentration. However, even samples with a water content of up to 25 % can be gently dried using the D-EVA.
In the experiment, 8 samples were spiked with surrogate standard solution, with a concentration in the middle calibration range, then mixed with different amounts of water and made up to 8 mL with methanol; all samples were evaporated with the D-EVA programme “Methanol”. Any sample that is almost dry is considered fi nished. When all samples are almost dry, they are dissolved in methanol/water 96:4 % (v/v), spiked with internal standard and analysed by LC-MS/MS.
Due to the high sample throughput of the Freestyle-XANA, another main objective of the D-EVA application is to evaporate faster than the methodology recommended by US-EPA 537.1, without risking loss of analytes, while achieving desired signal intensity without any personnel supervision. In the respective rotors, 23 samples in 15 mL or 10 samples in 50 mL FalcontubesTM can be used in parallel. The fast programme evaporates the eluates to dryness within 11 minutes and the longer program,
Fig. 3: Comparison of recoveries with regards to residual water
Author Contact Details Angelika Köpf, LCTech GmbH • Daimlerstr. 4, 84419 Obertaufkirchen, Germany • Tel: +49 8082 2717-310 • Email:
koepf@lctech.de • Web:
www.LCTech.de
What are PFAS?
Short for perfl uoroalkyl and polyfl uoroalkyl substances, PFAS are a collection of more than 4,700 chemicals that have been developed by industry to fulfi l a number of diff erent purposes. PFAS are a completely manmade phenomenon and do not occur anywhere naturally in our environment. Crucially, they are incredibly persistent, taking a thousand years or more to degrade in the atmosphere.
It’s for this reason that they’re known as “forever chemicals”. Indeed, the longevity of PFAS – plus their eff ortless mobility – means that they can accumulate over time and infi ltrate all parts of the globe. Today, PFAS are found almost everywhere, from the pizza box that your takeaway dinner arrives in to the bloodstreams of you and your loved ones to even polar bears living at the North Pole.
Breaking down the science PFAS are created by merging a chain of carbon molecules with a fl uorine element. It’s this carbon-fl uorine bond that is responsible for their incredibly long lifespan, since it’s notoriously one of the strongest connections known to man. PFAS are generally divided into polymers and non-polymers; the former refers to those with 12 or more carbon molecules in their chain, while the latter covers all else.
PFAS were fi rst developed in the 1940s and were used to imbue surfaces or materials with water-, stain- or grease-resistant properties. Today, their deployment extends far beyond those simplistic applications (although they are still very much in use), encompassing enhanced oil recovery, fi refi ghter foam creation, food processing equipment and many, many more uses.
Troubling discoveries
It wasn’t until the 1970s that scientists began to realise that PFAS had some concerning properties. To date, there are some PFAS which researchers have not been able to determine a half-life for, meaning they cannot place a timescale on how long it will take the chemicals to disappear from our environment. As such, PFAS are a problem as pervasive as plastic pollution – but an invisible one.
Although our understanding of the full impacts of prolonged exposure to PFAS is not complete, studies have shown that having high levels of the chemicals in your bloodstream can lead to a whole host of health problems. In particular, PFAS have been linked to both kidney and testicular cancer, as well as elevated cholesterol levels, pregnancy-induced hypertension, thyroid disease and ulcerative colitis.
What can be done? Although it’s virtually impossible to avoid coming into contact with PFAS through the air we breathe, the materials we handle and the food we consume, it is essential to ensure that we limit our exposure as much as possible. Since PFAS have the potential to bypass wastewater treatment fi lters and infi ltrate water supplies, regular testing is necessary to monitor concentrations of the chemicals in the water we depend upon for our survival as a species.
Due to the varied nature of PFAS components, testing a sample of water for their presence is no small challenge. However, advancements are being made in the fi eld which make the process simpler and easier. The article Screening technique for Adsorbable Organic Fluoride (AOF) concentrations with the Xprep C-IC goes into detail on one of the most promising recent developments in this fi eld.
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For More Info, email:
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