VATIS UPDATE Article

The Hong Kong Polytechnic University (PolyU) has developed highly selective formaldehyde rapid detection method which involves only simple procedures. It can test 10 food samples on-site in one go in comparison to traditional methods which entail 30 minutes for the testing of each food sample one by one. Its cost is less than HK$30, which is 90% lower than traditional testing methods. If the food sample contains formaldehyde, under hand-held UV light, the fluorescent probes will appear to be fluorescent blue, which can be easily observed by naked eyes.

Traditional methods for formaldehyde measurement are liquid chromatography which involves chemical derivation of formaldehyde, chromatographic separation and instrumental analysis of the formaldehyde content with reference to the sample standard. Based on prior research on a chemical reaction that enables chemical coupling of 1) amine-functionalized resins, 2) formaldehyde and 3) fluorescent dyes via gold catalysis, PolyU researchers have developed fluorescent probes for rapid detection of formaldehyde in food with excellent selectivity and high stability.

Firstly, researchers added pre-treated food samples, amine-functionalized resins, fluorescent dyes and gold catalysts into a container, and heated the solution at 50 °C for 1 hour. After that, organic solvents were added to wash out excessive reagents. The three-component coupling reaction will connect resin-linked sterically bulky amines and fluorescent alkynes through chemical bonding with formaldehyde in food so that the surface of the resins can give out fluorescent blue colour under hand-held UV light.