Environmental pollutant analysis typically requires complex sample pretreatment steps such as filtration, separation, and preconcentration. When solid materials such as sand, soil, or food residues are present in water samples, analytical accuracy often decreases, and filtration can unintentionally remove trace-level target pollutants along with the solids.
To address this challenge, a joint research team led by Dr. Ju Hyeon Kim at the Korea Research Institute of Chemical Technology (KRICT) , in collaboration with Professor Jae Bem You's group at Chungnam National University, has developed a microfluidic-based analytical device that enables direct extraction and analysis of pollutants from solid-containing samples without any pretreatment.
Water, food, and environmental samples encountered in daily life may contain trace amounts of hazardous contaminants that are invisible to the naked eye. Accurate detection requires selective extraction and concentration of target analytes, a process traditionally achieved using liquid–liquid extraction (LLE). However, conventional LLE requires large volumes of solvents and is difficult to automate. Although liquid–liquid microextraction (LLME) has been introduced to overcome these limitations, its practical application has remained limited because samples containing solid particles still require a filtration step prior to extraction.
Existing analytical approaches typically follow a multistep workflow—solid removal, extraction, and analysis—which increases time and cost while reducing analytical reliability. These limitations pose significant challenges in fields closely related to public health, including environmental monitoring, drinking water safety, and pharmaceutical residue analysis.
The research team overcame these issues by designing a trap-based microfluidic device that confines a small volume of extractant droplet inside a microchamber while allowing the sample solution to flow continuously through an adjacent microchannel. This configuration enables rapid and selective mass transfer of target analytes into the extractant, while solid particles pass through the channel without interference. After extraction, the extractant droplet can be retrieved for downstream analysis.
Using this device, the researchers successfully detected perfluorooctanoic acid (PFOA), a representative per- and polyfluoroalkyl substance (PFAS) increasingly regulated due to environmental and health concerns, as well as carbamazepine (CBZ), an anticonvulsant pharmaceutical compound. Notably, CBZ was extracted directly from sand-containing slurry samples without filtration. PFOA signals were detected within five minutes, and CBZ extracted from slurry samples was clearly identified using high-performance liquid chromatography (HPLC).
The results demonstrate that the proposed microfluidic platform significantly reduces analytical steps while maintaining high reliability, highlighting its potential as a compact and automatable solution for environmental pollution monitoring, food safety inspection, and pharmaceutical and bioanalytical applications.
Dr. Kim noted that "integrating multiple pretreatment steps into a single process offers substantial advantages for on-site analysis and automated systems," while KRICT President Young-Kuk Lee emphasized that "this technology can enhance the reliability of environmental and food safety analyses that directly impact public health."
The study was published as a cover article in ACS Sensors (Impact Factor: 9.1; top 3.2% in JCR Analytical Chemistry) in December 2025. Dr. Ju Hyeon Kim (KRICT) and Professor Jae Bem You (Chungnam National University) served as corresponding authors, with Sung Wook Choi as the first author.
