A water-soluble fluorescent sensor for the quick discrimination of H2O and D2O by notable signal outputs and the real-time monitoring of food spoilage in a non-contact mode

Abstract

Due to the very similar chemical and physical properties, D₂O and H₂O cannot be discriminated easily by convenient and cost-effective ways. Up to now, small organic molecules with active deprotonating ability in a very weak alkaline solution are proposed to deal with this fascinating yet challenging research. In this contribution, TPA-DP-COOH, a carboxylic acid group-substituted fluorescent substance, is demonstrated as a sensor to detect D₂O and H₂O with an external interference-free style, which not only displays a huge different signal output in D₂O and H₂O, but also very low limits of detection (LOD) as 49.08 ppm (D₂O in H₂O) and 0.23 ppm (H₂O in D₂O), respectively. Thus, these excellent sensing behaviors encourage us to fabricate TPA-DP-COOH and TPA-DP-COOK-absorbed filter papers as cost-effective and portable test strips, which are able to monitor the spoilage of Dimocarpus longan Lour and white leg shrimp in a non-contact mode during the storing process.