Aggregation-induced emission luminogen based molecularly imprinted ratiometric fluorescence sensor for the detection of Rhodamine 6G in food samples

Abstract

Using an aggregation-induced emission luminogen (AIEgen) as the fluorescence signal part, a novel molecularly imprinted polymers (MIPs) based ratiometric fluorescence sensor (AIE-MIPs-1) was developed for detecting Rhodamine 6G (Rh6G) in food samples including dried papaya and beverage. The sensor exhibited strong blue fluorescence itself at 420 nm. Upon the adsorption of Rh6G, the original fluorescence intensity decreased while a new fluorescence emission peak at 562 nm increased gradually, which showed typical ratiometric fluorescence change. Good linear relationship between the fluorescence intensity ratio (I₅₆₂/I₄₂₀) and the concentration of Rh6G was obtained in the range of 0.0-10.0 μmol/L. A detection limit of 0.26 μmol/L Rh6G was achieved. Moreover, AIE-MIPs-1 exhibited good sensitivity towards Rh6G over other colorants. This study provided a new strategy for construction of MIPs-based fluorescence sensors by introducing AIEgens as the fluorescence signal part, which will significantly expand the categories and application ranges of MIPs-based fluorescence sensors.

Keywords: Aggregation-induced emission; Fluorescence sensor; Molecularly imprinted polymers; Ratiometric fluorescence change; Rhodamine 6G.