One-pot and surfactant-free synthesis of N-doped mesoporous carbon spheres for the sensitive and selective screening of small biomolecules

A Novel Electrochemical Sensor Based on Pd Confined Mesoporous Carbon Hollow Nanospheres for the Sensitive Detection of Ascorbic Acid, Dopamine, and Uric Acid

In this study, we designed a novel electrochemical sensor by modifying a glass carbon electrode (GCE) with Pd confined mesoporous carbon hollow nanospheres (Pd/MCHS) for the simultaneous detection of ascorbic acid (AA), dopamine (DA), and uric acid (UA). The structure and morphological characteristics of the Pd/MCHS nanocomposite and the Pd/MCHS/GCE sensor are comprehensively examined using SEM, TEM, XRD and EDX. The electrochemical properties of the prepared sensor are investigated through CV and DPV, which reveal three resolved oxidation peaks for AA, DA, and UA, thereby verifying the simultaneous detection of the three analytes. Benefiting from its tailorable properties, the Pd/MCHS nanocomposite provides a large surface area, rapid electron transfer ability, good catalytic activity, and high conductivity with good electrochemical behavior for the determination of AA, DA, and UA. Under optimized conditions, the Pd/MCHS/GCE sensor exhibited a linear response in the concentration ranges of 300-9000, 2-50, and 20-500 µM for AA, DA, and UA, respectively. The corresponding limit of detection (LOD) values were determined to be 51.03, 0.14, and 4.96 µM, respectively. Moreover, the Pd/MCHS/GCE sensor demonstrated outstanding selectivity, reproducibility, and stability. The recovery percentages of AA, DA, and UA in real samples, including a vitamin C tablet, DA injection, and human urine, range from 99.8-110.9%, 99.04-100.45%, and 98.80-100.49%, respectively. Overall, the proposed sensor can serve as a useful reference for the construction of a high-performance electrochemical sensing platform.

Synthesis of cobalt phosphide hybrid for simultaneous electrochemical detection of ascorbic acid, dopamine, and uric acid

Ascorbic acid (AA), dopamine (DA), and uric acid (UA) are important biomarkers for the clinical screening of diseases. However, the simultaneous determination of these three analytes is still challenging. Herein, we report a facile metal-organic framework (MOF)-derived method to synthesize a cobalt phosphide (Co2P) hybrid for the simultaneous electrochemical detection of AA, DA and UA. The introduction of highly dispersed Co2P nanoparticles onto a P, N-doped porous carbon matrix is responsible for providing abundant active sites and facilitating electron transfer, thereby contributing to the improved electrocatalytic performance of the hybrid. Well-resolved oxidation peaks and an enhanced current response for the simultaneous oxidation of AA, DA, and UA were achieved using a Co2P hybrid-modified screen-printed electrode (Co2P hybrid-SPE) with the differential pulse voltammetry (DPV) method. The detection limits for AA, DA, and UA in simultaneous detection were calculated as 17.80 μM, 0.018 μM, and 0.068 μM (S/N = 3), respectively. Furthermore, the feasibility of using Co2P hybrid-SPE for the simultaneous detection of AA, DA, and UA in real serum samples was also confirmed.