"Turn-on" fluorescent sensor for glycerol based on hydrazine-bridged bis-tetraphenylimidazole

Glycerol is an important biological molecule, but no facile and on-site fluorescence sensor for detecting glycerol has been reported up to now. In this work, the organic fluorescent sensor for glycerol was prepared based on hydrazine-bridged bis-tetraphenylimidazole (HBT), which exhibited an excellent "turn-on" blue fluorescence response in detecting glycerol for the first time. The good sensing selectivity for glycerol among all kinds of organic molecules and ions was confirmed with the low detection limitation (LOD=0.48 μM). The sensing mechanism was proposed as that the photo-induced electron transfer process between the lone pair electrons of the Schiff group and the tetraphenylimidazole moiety was interrupted by the multiple hydrogen-bond action between glycerol and HBT. The sensing ability of HBT for glycerol was successfully used for the detection of glycerol in test paper and real samples (glycerine enema and aloe vera gel), demonstrating the good potential for simple, rapid and in-situ detection of glycerol in daily life.