Mihret Yeabsira, Sisay Getu, Diro Abebe, Hailemariam Solomon, Kitte Shimeles Addisu
Department of Chemistry, College of Natural Sciences, Jimma University, 378 Jimma, Ethiopia.
Department of Physics, College of Natural Sciences, Jimma University, 378 Jimma, Ethiopia.
ACS Omega. 2023 Nov 30;8(49):46869-46877. doi: 10.1021/acsomega.3c06487. eCollection 2023 Dec 12.
Here, a highly sensitive electrochemical sensor for detection of tryptophan (Trp) using a nitrogen defect graphitic carbon nitride-modified glassy carbon electrode (ND-CN/GCE) was introduced. ND-CN/GCE showed a higher oxidation current for Trp than the graphitic carbon nitride-modified glassy carbon electrode (-CN/GCE) and bare glassy carbon electrode (BGCE). The synthesized nitrogen defect-rich graphitic carbon nitride (ND-CN) was characterized using X-ray photoelectron spectroscopy, X-ray diffraction spectroscopy, Fourier-transform infrared spectroscopy, scanning electron microscopy, and transmission electron microscopy. Electrochemical impedance spectroscopy and cyclic voltammetry were used to further analyze the electrochemical properties of BGCE, -CN/GCE, and ND-CN/GCE. The oxidation of Trp at ND-CN/GCE is a diffusion-controlled process at pH 3.0. It was calculated that the transfer coefficient, rate constant, and diffusion coefficient of Trp were 0.53, 2.24 × 10 M s, and 8.3 × 10 cm s, respectively, at ND-CN/GCE. Trp was detected using square wave voltammetry, which had a linear range from 0.01 to 40 μM at pH 3.0 and a limit of detection of about 0.0034 μM (3σ/). Analyzing the presence of Trp in a milk and multivitamin tablet sample with a percentage recovery in the range of 97.0-108% satisfactorily demonstrated the practical usability of the electrochemical sensor. The ND-CN/GCE additionally displays good repeatability and reproducibility and satisfactory selectivity.
在此，介绍了一种用于检测色氨酸（Trp）的高灵敏度电化学传感器，该传感器使用氮缺陷石墨相氮化碳修饰玻碳电极（ND-CN/GCE）。与石墨相氮化碳修饰玻碳电极（-CN/GCE）和裸玻碳电极（BGCE）相比，ND-CN/GCE对Trp表现出更高的氧化电流。使用X射线光电子能谱、X射线衍射光谱、傅里叶变换红外光谱、扫描电子显微镜和透射电子显微镜对合成的富含氮缺陷的石墨相氮化碳（ND-CN）进行了表征。采用电化学阻抗谱和循环伏安法进一步分析了BGCE、-CN/GCE和ND-CN/GCE的电化学性质。在pH 3.0时，Trp在ND-CN/GCE上的氧化是一个扩散控制过程。经计算，在ND-CN/GCE上Trp的转移系数、速率常数和扩散系数分别为0.53、2.24×10 M s和8.3×10 cm s。采用方波伏安法检测Trp，在pH 3.0时线性范围为0.01至40 μM，检测限约为0.0034 μM（3σ/）。对牛奶和多种维生素片样品中Trp的存在进行分析，回收率在97.0-108%范围内，令人满意地证明了该电化学传感器的实际可用性。此外，ND-CN/GCE还具有良好的重复性、再现性和令人满意的选择性。
