Facile fluorescent glucose detection based on the Maillard reaction

The Maillard reaction, a typical reaction between reducing sugars and amino-compounds, has been considered to be an excellent platform to construct fluorescent probes for detecting different analytes. In this work, an amino-modified hemicyanine dye, 4-(4-aminostyryl)-1-methylpyridinium iodide (ASMPI), has been synthesized as a probe for the fluorescent detection of glucose. The intramolecular charge-transfer (ICT) performance and fluorescence emission property of ASMPI was characterized by UV–vis and fluorescence spectra. According to FTIR and XPS results, the Maillard reaction occurred after adding glucose to ASMPI aqueous solution. The obtained Maillard reaction products resulted in the enhancement of fluorescence emission due to the weakening of ICT process. The effects of solvent polarity (adding ethanol) and temperature on the fluorescent emission of ASMPI-glucose Maillard products were investigated to further amplify their fluorescence signal. The results indicated that the optimal experimental condition were that the ratio of ethanol/water was 9:1 and the temperature was 40 °C. Based on this, a fluorescent assay for the detection of glucose was developed.