Differential pulse voltammetric quantitation of kynurenic acid in human plasma using carbon-paste electrode modified with metal-organic frameworks

In the present work, metal-organic frameworks (MOFs), MIL-101(Cr), and nanoparticles are successfully ob-tained using the hydrothermal procedure. SEM, Brunauer-Emmett-Teller, ultraviolet-visible spectrophotometry, and Fourier transform infrared spectroscopy are used to investigate the morphology of MIL-101(Cr). The pre-pared MOF showed high porosity and activity centers, leading to good electrochemical performance. These essential features are used to fabricate an electrochemical sensor that showed good responses for determining kynurenic acid (KYNA). In comparison to the modified electrode (MIL 101(Cr)-CPE.), the bare electrode (CPE) has no responses toward KYNA at a potential range from-0.30 to 0.70 V. The modified electrode shows reversible current responses for KYNA at a potential of around 0.39 V. Under the optimum experimental con-ditions, the electrochemical behavior of KYNA is studied by cyclic voltammetry (CV) on the modified electrode surface, and quantitative measurements are investigated by differential pulse voltammetry (DPV). The fabricated modified electrode displays a linear range from 0.10 to 150.00 mu M with a calibration sensitivity of 3.57 A M-1. Also, the diffusion coefficient and the detection limit of the modified electrode for detection of the KYNA were obtained to be 4.70 x 10-5 cm2s- 1 mu A and 17.00 nM, respectively. Furthermore, the proposed sensor can be successfully used for analyzing KYNA in human plasma samples, and recoveries of 95.15%-105.73% are ob-tained for spiked KYNA in human plasma.