A novel ratiometric dehydroabietic acid-based fluorescent probe for detecting HPO42- and its application in food samples

Monohydrogen phosphate (HPO42-) is one of the most ubiquitous additives applied in a wide range of food products and played an important role in many biological processes. Therefore, the selective and sensitive detection techniques of HPO42- are of great significance. A novel ratiometric dehydroabietic acid-based fluorescent probe named methyl (6 R,9aS)− 11-bromo-2-(5-bromo-2-hydroxyphenyl)− 6,9a-dimethyl- 4,5,5a,6,7,8,9,9a-octahydro-1H-phenanthro[1,2-d]imidazole-6-carboxylate (CPL) was designed and synthesized for monitoring HPO42-. The probe CPL had a significant fluorescent response to HPO42- changing from cyan to violet fluorescence. CPL demonstrated many fascinating advantages including low limit of detection (28 nM), high selectivity, short response time (20 s) and wide appropriate pH range (5−12). The detection mechanism was verified by FTIR, 1H NMR, DFT calculation and Job’s plot experiment. Subsequently, the probe CPL was applied to quantitatively detect HPO42- contents in food samples (shrimp meat, Mozzarella cheese, Basa fish fillet and bread). In addition, CPL was successfully utilized for the bioimaging of HPO42- in onion epidermal cells and zebrafishes.