Department of Biomedical Engineering, South Tehran Branch, Islamic Azad University, Tehran, Iran.
Nanotechnology. 2020 Oct 23;31(43):435504. doi: 10.1088/1361-6528/aba20e. Epub 2020 Jul 2.
In this paper, nicotine (NIC) was detected by cyclic voltammetry (CV) using a modified glassy carbon (GC) electrode. To do this, the surface of the GC electrode was modified by hybrid nanofiber obtained from the electrospinning method. Hybrid nanofibers were produced through the dispersion of carboxylated multi-walled carbon nanotube (MWCNT-COOH) as an inorganic component in the chitosan (CS) polymer matrix as an organic component. The nanofibers showed unique morphology and high surface area value. With the increase of functionalized carbon nanotube content in the nanofibers, the mean pore diameter and average nanofiber diameter increased. The electrochemical properties of nanofibers towards the sensing of NIC were investigated by the CV method. NIC was irreversibly reduced with the use of a CS/MWCNT-COOH electrode, a controlled process with two protons and two electrons. An oxidation signal at lower potential with higher current was obtained for NIC with the use of a polymer-modified electrode compared to a GC electrode. This was as a result of the electrocatalytic effect of the hybrid nanofibers due to the ability of carbon nanotubes to increase the rate of electron transfer. Under optimum conditions, the oxidation of NIC occurred at 0.82 eV with a pH of 7.4. The linear calibration curve was in the concentration range of 0.1-100 μM NIC (R = 0.9987) with a detection limit of 30 nM. For 100 parallel 10 μM NIC diagnoses for five replicates, 97.2% with a standard deviation of 4.08 maintained their stability over the first cycle. This indicates that the CS/MWCNT-COOH electrode has excellent reproducibility and stability.
本文采用循环伏安法（CV）检测尼古丁（NIC），使用的是经过修饰的玻碳电极。为此，通过静电纺丝法制备的杂化纳米纤维对 GC 电极表面进行修饰。杂化纳米纤维是通过将羧基化多壁碳纳米管（MWCNT-COOH）作为无机成分分散在壳聚糖（CS）聚合物基质中制成的有机成分。纳米纤维具有独特的形态和高的比表面积值。随着纳米纤维中功能化碳纳米管含量的增加，平均孔径和平均纳米纤维直径增加。通过 CV 法研究了纳米纤维对 NIC 传感的电化学性质。使用 CS/MWCNT-COOH 电极时，NIC 不可逆还原，这是一个有两个质子和两个电子参与的受控过程。与 GC 电极相比，使用聚合物修饰电极时，NIC 获得了较低电位下具有更高电流的氧化信号。这是由于碳纳米管提高电子转移速率的能力导致的杂化纳米纤维的电催化作用。在最佳条件下，NIC 的氧化发生在 0.82 eV，pH 值为 7.4。在 0.1-100 μM NIC 的浓度范围内（R = 0.9987），线性校准曲线的检测限为 30 nM。对于 100 个 10 μM NIC 的平行 10 次诊断，5 个重复中有 97.2%的稳定性，标准偏差为 4.08。这表明 CS/MWCNT-COOH 电极具有优异的重现性和稳定性。
