Portable AIE hydrogel sensor for rapid and visual field detection of heavy metal residue in food

Mercury contamination causes a wide range of symptoms in organisms, and affects human brain, kidneys and nervous system in particular. Most food sources high in mercury come from saltwater species like fish and other sea animals. Recently, fluorescent biofilm, electrostatic spinning film, and hydrogel were used for the potable detection of mercury. However, the photostability of the fluorescent probe in the film and the challenge of solid food sample analysis are the main issues to be addressed. In this work, sodium alginate hydrogel (SA) was used for developing a hydrogel sensor in combination with the phenanthroline modified-tetraphenylethylene (TPE) derivatives (DTPEP). Based on its aggregation-induced emission (AIE) characteristic and high specificity to mercury, the AIE hydrogel mercury sensor was coated on different carriers, such as gloves, sticky notes, etc., as flexible sensors for portable and rapid field testing of mercury contamination. The visualization results were analyzed using the greyscale-based Android software "Detect" to Quantification of Hg2+. The detection limit could be as low as 0.06 μM with the detection time within 15 min. The gray value was linearly related to the concentration of Hg2+, ranging from (0–2 μM). The flexible Visual and rapid sensing systems have not only great potential applications in the detection of mercury in food samples but are also suitable for the detection of environmental and food contaminants.