Shape-optimized nanosized MOF-74T and CdS composite by transformation strategy for ultrasensitive detection of metabolic modulators trimetazidine

Due to the unique structure and diversified functions of metal-organic frameworks (MOFs), numerous studies on the morphology control of MOFs have been gradually carried out lately, but there are still plenty challenges. In this paper, MOF-74T was synthesized indirectly by using ZIF-67 as an intermediate through transformation strategy and control of the ligand 2,5-dihydroxyterephthalic acid (H₄DOBDC) concentration. Meanwhile, CdS nanorods were introduced to change nucleation sites of MOF-74T, so that the shape-optimized tiny MOF-74T particles gathered on the surface of CdS. And the morphology of the CdS/MOF-74T composite was transformed from rhomboidal dodecahedron to rough rod-like. The ratio of CdS and MOF-74T in CdS/MOF-74T synthesis process was also optimized. The optimized composite can be applied in electrochemical sensing because more active sites are exposed, mass transfer resistance and carriers diffusion length are reduced. CdS/MOF-74T can be used for the ultrasensitive detection of metabolic regulator trimetazidine (TMZ) by square wave voltammetry (SWV) method with peak potentials at 1.0 V. The logarithm of response current and the logarithm of TMZ concentration shows a good linear relationship in the wide concentration range of 50 nM ∼ 200 μM (R² = 0.9939), with a very low detection limit of 27.4 nM (S/N = 3). The sensor has also been applied to the TMZ detection in human urine sample, which indicates that CdS/MOF-74T has an excellent application prospect in medical research.