A research team from South Korea and France has developed a new arsenic detection technology.
Arsenic is a contaminant discharged into the environment through various industrial activities, such as pesticides, preservatives, and semiconductor manufacturing. Trivalent arsenic is highly toxic and soluble in water, contaminating groundwater, and prolonged exposure can lead to serious health issues, including cancer. The World Health Organization (WHO) limits the permissible arsenic levels in drinking water to below 10 ppb.
The problem is that detecting arsenic is not easy. Existing technologies have been costly and complicated, making them difficult to utilize in practice.
Professor Kim Young-ki from Pohang University of Science and Technology (POSTECH) and doctoral student Kim Hye-in developed a new arsenic detection sensor in collaboration with a research team from France's Littoral Opal Coast University.
The sensor developed by the research team utilized the unique properties of liquid crystals. Liquid crystals are materials used in everyday devices such as TVs and smartphone displays and respond sensitively to minute changes in molecular arrangements. Such changes can be observed as optical signals visible to the naked eye.
The research team placed carbon dots coated with L-cysteine, which selectively binds well with arsenic, at the interface where water meets the liquid crystal. As a result, if arsenic is present in water, this substance binds with L-cysteine, causing a change in the arrangement of the liquid crystal molecules, which results in a clear color change, making it easy to confirm the presence and concentration of arsenic.
Experimental results showed that this sensor quickly detected arsenic across a wide range from 1 ppb to 4 ppm. The detection time was also short, ranging from a few seconds to a maximum of 2 minutes, capable of detecting concentrations more than 10 times lower than the standards recommended by WHO.
The greatest advantage of this technology is its applicability in the field. It allows for immediate confirmation of arsenic contamination without complex sample pretreatment processes or expensive analytical equipment, making it expected to be useful in developing countries that lack equipment and infrastructure.
Professor Kim Young-ki noted, "The issue of arsenic contamination is emerging as a serious environmental problem not only in developing countries but globally," and added, "I hope this research enables convenient yet highly sensitive arsenic detection and contributes to ensuring safe drinking water."
References
Advanced Optical Materials (2025), DOI: https://doi.org/10.1002/adom.202403136