The determination of per- and polyfluoroalkyl substances (PFAS) — commonly referred to as “forever chemicals” — and other pollutants in water samples typically relies on pretreatment methods to isolate these contaminants. A less costly and time-consuming analytical approach has been devised by researchers from South Korea.

The microfluidic device described in ACS Sensors can displace liquid-liquid extraction and other pretreatment procedures by detecting PFAS and other pollutants directly from environmental samples. The tool uses a trap-based microfluidic design to extract contaminants directly from samples, bypassing filtration steps.

A tiny droplet of extractant is held stationary within a microchamber while the contaminated sample flows through an adjacent channel. As the liquid passes by, target pollutants move into the extractant droplet through rapid mass transfer. Solid particles such as sand or food residues travel straight through the channel without interfering with the extraction process. When the process is completed, the droplet is retrieved for final analysis.

The method successfully detected the PFAS perfluorooctanoic acid in addition to carbamazepine (CBZ), an anticonvulsant pharmaceutical compound extracted directly from sand-containing slurry samples without filtration. PFAS signals were detected within five minutes, and CBZ extracted from slurry samples was clearly identified using high-performance liquid chromatography.

Researchers from Kyungpook National University, Korea Research Institute of Chemical Technology and Chungnam National University contributed to this analytical development.