[Study of fluorescence spectra of starch suspension]

To achieve detection, monitoring and automation of starch graft copolymerzation, the investigation was carried out according to the luminescence of free radical produced in the reaction. The investigation on the fluorescence spectra of starch-water suspension excited by ultraviolet light and its characteristics contributes to the study of the characteristics and mechanisms of free radical coming into being, emitting and disappearing. The experimental results indicate that starch-water suspension can emit fluorescence, whose peak wavelength is about 339 nm. Furthermore, the physical mechanism of fluorescence emission of starch is analyzed. It is considered that this fluorescence comes from the transition from nonbonding electrons in the hetero-atom (O) of the functional group (C--O--C) called ether linkage to the antibonding orbital sigma*.