Rison Sherin, Rajeev Rijo, Bhat Vinay S, Mathews Agnus T, Varghese Anitha, Hegde Gurumurthy
Christ Academy Institute For Advanced Studies Christ Nagar Bangalore 560083 India.
Department of Chemistry, CHRIST (Deemed to be University) Bangalore 560029 India
RSC Adv. 2021 Nov 24;11(60):37877-37885. doi: 10.1039/d1ra07366d. eCollection 2021 Nov 23.
Electrochemically deposited ZnO nanoparticles on a pencil graphite electrode (PGE) coated with graphene generate a noteworthy conductive and selective electrochemical sensing electrode for the estimation of cortisol. Electrochemical techniques such as cyclic voltammetry (CV) analysis and electrochemical impedance spectroscopic (EIS) tests were adopted to analyze and understand the nature of the modified sensor. Surface morphological analysis was done using various spectroscopic and microscopic techniques like X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). Structural characterization was conducted by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The effect of scan rate, concentration, and cycle numbers was optimized and reported. Differential pulse voltammetric (DPV) analysis reveals that the linear range for the detection of cortisol is 5 × 10M - 115 × 10 M with a very low-level limit of detection value (0.15 nM). The demonstrated methodology has been excellently functional for the determination of salivary cortisol non-enzymatically at low-level concentration with enhanced selectivity despite the presence of interfering substances.
在涂有石墨烯的铅笔石墨电极（PGE）上通过电化学沉积的氧化锌纳米颗粒，可生成一种用于测定皮质醇的具有显著导电性和选择性的电化学传感电极。采用循环伏安法（CV）分析和电化学阻抗谱（EIS）测试等电化学技术来分析和理解修饰传感器的性质。使用X射线光电子能谱（XPS）、透射电子显微镜（TEM）和扫描电子显微镜（SEM）等各种光谱和显微镜技术进行表面形态分析。通过X射线衍射（XRD）和傅里叶变换红外光谱（FTIR）进行结构表征。对扫描速率、浓度和循环次数的影响进行了优化并报告。差分脉冲伏安法（DPV）分析表明，皮质醇检测的线性范围为5×10⁻⁶ M - 115×10⁻⁶ M，检测值的下限极低（0.15 nM）。所展示的方法在低浓度下非酶法测定唾液皮质醇方面表现出色，尽管存在干扰物质，但仍具有增强的选择性。
