Nitrite (NO₂⁻) is commonly used as a food additive, but when ingested, it can harm the body's oxygen transport system. The World Health Organization limits NO₂⁻ to 1.0 mg/L in drinking water and 30 mg/kg in meat products. However, current nitrite detection methods are often complicated.
Recently, a team of researchers led by Prof. JIANG Changlong from Institute of Solid State Physics, the Hefei Institutes of Physical Sciences of the Chinese Academy of Sciences, developed a novel thermosensitive hydrogel-based fluorescence probe for real-time visualization and detection of nitrite.
They published the progress in Journal of Hazardous Materials.
"With this probe and a smartphone, the nitrite data is available at a glance,” said Dr. LI Lingfei, a member of the team.
In this research, the functionalized thermosensitive hydrogel doped with fluorescent probes was designed to make it easier to get information of NO₂⁻. Gold nanoclusters (Au NCs) and carbon-based dots were added into the hydrogel’s multi-layered structure, which was made from P407, lignin, and cellulose. This created a material with special fluorescence properties and strong stability. The interconnected P407, lignin, and cellulose gave the hydrogel an excellent porous structure.
This novel Au NCs/LCG-P407 fluorescent hydrogel has been designed with the objective of optimizing portable and efficient device strategies. It provides a basis for further development of sensing platforms for the detection of environmental and hazardous substances in food safety.
The hydrogel sensor can also be paired with a smartphone app to visually measure NO₂⁻ in water, making detection easier and more practical.
This research marks advancement in hydrogel applications and highlights its potential to enhance food safety monitoring systems, according to the team.
Schematic representation of Au-NCs/LCG-P407 fluorescent hydrogel for the detection of NO₂⁻. (Image by LI Lingfei)