Selective recognition of 6-mercaptopurine based on luminescent metal–organic frameworks Fe-MIL-88NH2

A novel and rapid spectrofluorometry method for the recognition of 6-mercaptopurine (6-MP) has been developed based on luminescent metal–organic frameworks Fe-MIL-88NH 2 as fluorescent probe. The strong fluorescence of Fe-MIL-88NH 2 at 430   nm could be quenched by 6-MP directly, and the Fe-MIL-88NH 2 shows high selectivity for 6-MP compared to other thiol-containing amino acids such as homocysteine (Hcy), cysteine (Cys), glutathione (GSH), etc. Under optimal conditions, the relative fluorescence intensity was linearly proportional to the concentration of 6-MP in the range of 5–600   μM with the detection limit at 1.17   μM (S/N   =   3). Furthermore, the present approach has been successfully applied to the determination of 6-MP in human serum samples. The possible fluorescence quenching mechanism has also been investigated, where it is revealed that the quenching was attributed to competition of absorption of the light source energy as well as electron transfer between Fe-MIL-88NH 2 and 6-MP.