A sensitive metal–organic framework nanosensor with cation-introduced chirality for enantioselective recognition and determination of quinine and quinidine in human urine†
A post-synthetic modification (PSM) method has been employed to incorporate extra chiral binding sites into a chiral Cd-MOF [(CH3)2NH2][Cd(bpdc)1.5]·2DMA (1) (H2bpdc = 4,4′-biphenyldicarboxylate acid) to prepare a bifunctional MOF, 1-C-Eu. After PSM, the thermal and chemical stability of the parent framework is well preserved. More significantly, 1-C-Eu is designed to be a highly sensitive fluorescent probe that can be applied to the enantioselective recognition and determination of the chiral antimalarial drugs, quinine and quinidine. Many properties of the probe, including anti-interference ability, pH stability, reusability, and luminescence response speed, have been examined to evaluate the sensing performance of 1-C-Eu. In addition, the luminescent probe can be used to realize the detection of quinine and quinidine in human urine. The possible mechanism of distinguishing and sensing the epimers is also systematically discussed.