SiO₂-based molecularly imprinted polymer composites and its application in fluorescence sensor analysis of 3-chloro-1,2-propanediol in paper food contact materials

Chloropropanols are common contaminants in food. Recently, food safety issues caused by 3-chloro-1,2-propanediol (3-MCPD) in paper food contact materials (FCM) have become the focus. However, existing analytical methods have limitations such as poor specificity, cumbersome operation, and long time consumption. Therefore, in this study, the specificity of molecularly imprinted solid-phase extraction (MISPE) and the rapid response of fluorescence sensors are combined to develop a new analytical method for the determination of 3-MCPD in paper FCM. In this study, a switch-type fluorescent sensor with dansyl chloride as the luminescent group and o-phenylenediamine as the recognition group is developed. Visual analysis of 3-MCPD is achieved, which has good linearity in the range of 10–70 µg/L and a detection limit of 0.038 µg/L. Molecularly imprinted polymers (MIP) with specific recognition of 3-MCPD are prepared as solid-phase extraction column fillers, and their adsorption characteristics and directional extraction capabilities are discussed. It is confirmed that the MISPE synergistic fluorescent sensor analysis method has good recovery (99.16%) and accuracy (98.35%). The luminescence mechanism of the fluorescent sensor and the specific binding mechanism of 3-MCPD and MIP are explained by DFT calculation technology. It provides a novel and powerful platform for simple, rapid, and visual colorimetric analysis of 3-MCPD in paper FCM.