Visual Detection of Coumarin and Umbelliferone for Beverage Safety Based on Eu(III)‐Functionalized HOF Hybrids: Further Constructing an SVM‐Assisted Digital Anti‐Counterfeiting Platform

Abstract The development of rapid, sensitive, and intuitive intelligent fluorescent materials (IFMs) for monitoring beverage safety is important for human health. In this study, an emerging IFM, a dual‐emitting Eu 3+ ‐functionalized hydrogen‐bonded organic framework (Eu@HOF, Eu@ 1 ), is fabricated through coordination post‐synthetic modification. The ligand‐to‐metal charge transfer‐induced energy transfer (LMCT‐ET) from 1 to Eu 3+ provides Eu@ 1 with palpable red fluorescence. Eu@ 1 as a sensor can specifically discriminate coumarin (Cou), a common spice used in beverages but a suspected carcinogen, with high sensitivity, high efficiency, and excellent anti‐interference. Eu@ 1 can also quantitatively distinguish 7‐hydroxycoumarin (umbelliferone, Ulf), a metabolite of Cou, in chromatic and ratiometric modes. In realistic milk and soy milk samples, the detection limits (DL) of Eu@ 1 for Cou are 0.0979 and 0.0511 mg L −1 , respectively, whereas that of Ulf in practical serum samples is 0.0099 mg L −1 . Furthermore, based on the polyethylene‐vinyl acetate (PEVA) films, three digital anti‐counterfeiting platforms with multiple encryption information are constructed, assisted by a support vector machine. This work proposes a facile pathway for preparing Eu@HOF fluorescent sensors to determine beverage safety and opens the possibility of designing an efficient and precise multifunctional digital anti‐counterfeiting platform via machine learning.