The current research focused on designing a simple, inexpensive, and green electrochemical sensor for the sensitive estriol hormone (ETL) detection. To achieve this, a bare carbon nanotube paste electrode (BCNTPE) and electrochemically polymerized L-arginine (ARN)-modified carbon nanotube paste electrode (MCNTPE) were developed. The prepared electrochemical sensor was characterized using various techniques, such as field-emission scanning electron microscopy (FE-SEM), electrochemical impedance spectroscopy (EIS), differential pulse voltammetry (DPV), and cyclic voltammetry (CV) methods. The investigation of the electrochemical oxidation nature of ETL in a supporting electrolyte of phosphate buffer solution (PBS) with pH 6.5 was carried out using a modified electrode (PARNMCNTPE) having superior electrocatalytic activity and more electrochemical active spots than the BCNTPE. Significant parameters like the impact of the pH of PBS, potential scan rate, and ETL concentration on the electrochemical behavior of ETL at the surface of the PARNMCNTPE were investigated. The potential scan rate and pH of PBS variation influence that the ETL oxidation at the PARNMCNTPE surface proceeded via pH-dependent and adsorption-controlled reaction pathways. The PARNMCNTPE senses ETL in the range from 2 × 10^–6 to 90 × 10^–6 M with a lower limit of detection (LOD) of 3.25 × 10^–7 M and a limit of quantification (LOQ) of 10.84 × 10^–7 M. The PARNMCNTPE shows decent stability, repeatability, and reproducibility for the detection of ETL. Additionally, the PARNMCNTPE analytical applicability was studied for ETL detection in medicinal samples.

Graphical abstract

中文翻译：

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使用聚（L-精氨酸）修饰的碳纳米管糊作为响应电化学传感器增强伏安法检测雌三醇激素

目前的研究重点是设计一种简单、廉价、绿色的电化学传感器，用于敏感的雌三醇激素（ETL）检测。为了实现这一目标，开发了裸碳纳米管糊状电极（BCNTPE）和电化学聚合L-精氨酸（ARN）修饰的碳纳米管糊状电极（MCNTPE）。使用场发射扫描电子显微镜（FE-SEM）、电化学阻抗谱（EIS）、微分脉冲伏安法（DPV）和循环伏安法（CV）等多种技术对制备的电化学传感器进行了表征。使用比 BCNTPE 具有优异电催化活性和更多电化学活性点的修饰电极（PARNMCNTPE）对 ETL 在 pH 6.5 磷酸盐缓冲溶液（PBS）支持电解质中的电化学氧化性质进行了研究。研究了 PBS pH 值、电势扫描速率和 ETL 浓度等重要参数对 PARNMCNTPE 表面 ETL 电化学行为的影响。 PBS 变化的电位扫描速率和 pH 值影响 PARNMCNTPE 表面的 ETL 氧化通过 pH 依赖性和吸附控制的反应途径进行。 PARNMCNTPE 可检测 2 × 10 ^–6至 90 × 10 ^–6  M 范围内的 ETL，检测下限 (LOD) 为 3.25 × 10 ^–7  M，定量限 (LOQ) 为 10.84 × 10 ^–7  M. PARNMCNTPE 在 ETL 检测中表现出良好的稳定性、重复性和再现性。此外，还研究了 PARNMCNTPE 分析适用性用于医药样品中的 ETL 检测。

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