Determination of ATP using a double-receptor sandwich method based on molecularly imprinted membrane and fluorescence-labeled uranyl-salophen complex

A double-receptor sandwich method for the fluorescence determination of adenosine triphosphate (ATP) is proposed in this paper. The solid phase receptor on the surface of glass slides is a molecularly imprinted membrane (MIM) containing an artificial nanocavity. It is constructed by a molecular imprinting technique using adenosine monophosphate (AMP) as a template molecule. The labeled receptor is a uranyl-salophen complex containing a fluorescent group or uranyl-salophen-fluorescein (USF). It is synthesized with salophen, 5-aminofluorescein, and uranyl. In a procedure of determining ATP, ATP in sample solution is first adsorbed on the surface of the glass slide through the combination of the AMP group in ATP with the nanocavity in MIM. Then, the adsorbed ATP binds USF through the coordination reaction of the phosphate group in ATP with uranyl in USF to form a sandwich-type structure of MIM-ATP-USF. The amount of ATP is detected through the fluorescence determination of USF bound on the slide. Under optimal conditions, the linear range for the determination of ATP is 0.3 to 4.8 nmol/mL with a detection limit of 0.041 nmol/mL. The proposed method has been successfully employed for the determination of ATP in real samples with the recoveries of 98.5 to 102.5 %.