Researchers develop quicker way to detect toxic ‘forever chemicals’ 

A new investigation from the University of Kansas, US, improved detection of PFAS, a family of so-called ‘forever chemicals’ in drinking water supplies. The method, which can measure trace pollution levels of PFAS in water more quickly and inexpensively than current techniques, recently was detailed in the open-source journal PLOS Water.


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“[PFAS chemicals] are man-made synthetic chemicals that contain poly- or perfluorinated carbons,” said study co-author Michael Zhuo Wang, professor of pharmaceutical chemistry at the University of Kansas. “They’re used in industry to make products like Teflon, anti-water coatings and firefighting foams. They have wide industrial applications. The problem is they don’t break down very easily in the environment.”

“Our body can absorb these compounds into the blood and tissues, and we don’t have the capacity to break them down either,” he said. “So, they accumulate in the body. Some studies show half-lives in the range of five to eight years in blood. More and more epidemiological studies suggest they may be associated with health issues, including developmental issues and certain cancers.”

Because of these serious health concerns, there’s a move among US lawmakers to tighten regulations of PFAS in drinking water. However, to comply, private and municipal labs will need to be able to economically and effectively detect PFAS compounds in ultra-trace amounts.

“The current EPA regulation limits some PFAS in drinking water to about four parts per trillion. Depending on the compound, regulated levels range roughly from four to ten parts per trillion,” Wang said. “They also have maximum contaminant level goals, which suggest ideally there should be zero. So, the target is essentially no detectable PFAS.”

Yet to determine whether PFAS are below the four parts-per-trillion level, labs need extremely sensitive tests beyond what’s capable at typical labs that analyse municipal drinking water.

“Typically, you start with 500 millilitres of water and use solid-phase extraction to concentrate it before analysis,” Wang said. “That concentration step is what drives time and cost. It requires large sample volumes, and the process is slow.”

To do so, they combined fast-flow solid-phase extraction (SPE) for concentrating PFAS from water samples with UPLC-MS/MS (Ultra Performance Liquid Chromatography–Tandem Mass Spectrometry) for very sensitive chemical analysis.

“The biggest improvement in our method is time reduction in sample concentration,” he said. “We reduced the time from hours to minutes. For a 500 millilitre sample, it used to take about 100 minutes to load. Now it takes about six to eight minutes, about a 20-fold reduction. To push detection even lower, you need larger volumes – up to four litres instead of 500 millilitres. That’s an eightfold increase in volume.”

With the original method, the same process would take about eight times longer, more than a half-day just for loading a sample onto a solid-phase extraction cartridge. “With the fast-flow approach, we can do that in about 60 minutes,” Wang said.

DOI: 10.1371/journal.pwat.0000501