In this paper, we report a double-receptor sandwich type fluorescence sensing method for the determination of fructose bisphosphates (FBPs) using fructose 1,6-bisphosphate (F-1,6-BP) as a model analyte based on uranyl-salophen complexes. The solid phase receptor is an immobilized uranyl-salophen (IUS) complex which is bound on the surface of glass slides by covalent bonds. The labeled receptor is another uranyl-salophen complex containing a fluorescence group, or uranyl-salophen-fluorescein (USF). In the procedure of determining F-1,6-BP in sample solution, F-1,6-BP is first adsorbed on the surface of the glass slide through the coordination reaction of F-1,6-BP with IUS. It then binds USF through another coordination reaction to form a sandwich-type structure of IUS-F-1,6-BP-USF. The amount of F-1,6-BP is detected by the determination of the fluorescence intensity of IUS-F-1,6-BP-USF bound on the glass slide. Under optimal conditions, the linear range for the detection of F-1,6-BP is 0.05-5.0 nmol mL(-1) with a detection limit of 0.027 nmol mL(-1). The proposed method has been successfully applied for the determination of F-1,6-BP in real samples with satisfactory results.
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