Development of a Single-System Dual-Emission Ratiometric Fluorescent Probe for Efficient Ethanol Sensing

Abstract

Determining the alcoholic strength is pivotal for quality control in the brewing industry; hence, developing a sensitive and accurate method for detecting alcoholic strength is of great importance. This study reported the preparation of a single-system dual-emission fluorescent probe via the solvothermal method, using tea extract as a reaction precursor. The probe exhibited two distinct emission bands with varying properties, where ethanol enhances aggregation-induced emission (AIE) in the blue region, while water promotes aggregation-caused quenching (ACQ) in the red region. This enables the probe to generate distinct fluorescence (FL) responses to different ethanol concentrations present in the alcohol sample. This is the first application of single-system dual-emission carbon dots (CDs), synthesized from biomass materials, for the detection of alcoholic strength. The probe demonstrated a strong positive linear correlation ( ${R}^{{2}} =0.9901$ ) with ethanol concentrations ranging from 10 vol.% to 70 vol.%, achieving a low detection limit of only 0.063 vol.%. Compared to previously reported probes, this one exhibited a broader linear range and a significantly lower limit of detection. The probe, furthermore, showcased high accuracy (errors <1 vol.%) and reproducibility relative standard deviation ((RSD) <0.6%) in actual samples detection, indicating its potential for alcoholic strength determination in liquor companies for practical application.