title: Colorimetric assay for on-the-spot alcoholic strength sensing in spirit samples based on dual-responsive lanthanide coordination polymer particles with ratiometric fluorescence.
abstract: This study demonstrates a new strategy for colorimetric detection of alcoholic strength (AS) in spirit samples based on dual-responsive lanthanide infinite coordination polymer (Ln-ICP) particles with ratiometric fluorescence. The ICP used in this study are composed of two components: one is the supramolecular Ln-ICP network formed by the coordination between the ligand 2,2'-thiodiacetic acid (TDA) and central metal ion Eu3+; and the other is a fluorescent dye, i.e., coumarin 343 (C343), both as the cofactor ligand and as the sensitizer, doped into the Ln-ICP network through self-adaptive chemistry. Upon being excited at 300 nm, the red fluorescence of Ln-ICP network itself at 617 nm is highly enhanced due to the concomitant energy transfer from C343 to Eu3+, while the fluorescence of C343 at 495 nm is supressed. In pure ethanol solvent, the as-formed C343@Eu-TDA is well dispersed and quite stable. However, the addition of water into ethanolic dispersion of C343@Eu-TDA destructs Eu-TDA network structure, resulting in the release of C343 from ICP network into the solvent. Consequently, the fluorescence of Eu-TDA turns off and the fluorescence of C343 turns on, leading to the fluorescent color change of the dispersion from red to blue, which constitutes a new mechanism for colorimetric sensing of AS in commercial spirit samples. With the method developed here, we could clearly distinguish the AS of different spirit samples within a wide linear range from 10% vol to 100% vol directly by "naked eye" with the help of UV-lamp (365 nm). This study not only offers a new method for on-the-spot visible detection of AS, but also provides a strategy for dual-responsive sensing mode by rational designing the optical properties of the Ln-ICP network and the guest, respectively.
authors.affiliation: School of Ecological and Environmental Sciences, East China Normal University, 500 Dongchuan Road, Shanghai 200241, China. Electronic address: jjdeng@des.ecnu.edu.cn.
authors.forename: Jingjing
authors.initials: J
authors.lastname: Deng
authors.affiliation: Department of Chemistry, East China Normal University, 500 Dongchuan Road, Shanghai 200241, China.
authors.forename: Guoyue
authors.initials: G
authors.lastname: Shi
authors.affiliation: School of Ecological and Environmental Sciences, East China Normal University, 500 Dongchuan Road, Shanghai 200241, China. Electronic address: tszhou@des.ecnu.edu.cn.
authors.forename: Tianshu
authors.initials: T
authors.lastname: Zhou
mesh_terms: D000438:Alcohols / Q000032:analysis*; D003124:Colorimetry / Q000379:methods*; D056831:Coordination Complexes / Q000737:chemistry*; D003300:Copper / Q000737:chemistry; D005453:Fluorescence; D028581:Lanthanoid Series Elements / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D011108:Polymers / Q000737:chemistry*; D013050:Spectrometry, Fluorescence; D013052:Spectrometry, X-Ray Emission
chemical_list: D000438:Alcohols; D056831:Coordination Complexes; D028581:Lanthanoid Series Elements; D011108:Polymers; D003300:Copper
keywords: Alcoholic strength; Colorimetric assay; Dual response; Lanthanide coordination polymer particles; Ratiometric fluorescence