Department of Chemistry, Physics and Environment, Faculty of Sciences and Environment, "Dunărea de Jos" University of Galaţi, 47 Domnească Street, 800008 Galaţi, Romania.
Sensors (Basel). 2020 Nov 24;20(23):6724. doi: 10.3390/s20236724.
The present paper deals with the electrochemical behavior of three types of sensors based on modified screen-printed electrodes (SPEs): a sensor based on carbon nanofibers (CNF/SPE), a sensor based on nanofibers of carbon modified with gold nanoparticles (CNF-GNP/SPE) and a biosensor based on nanofibers of carbon modified with gold nanoparticles and tyrosinase (CNF-GNP-Ty/SPE). To prepare the biosensor, the tyrosinase (Ty) was immobilized on the surface of the electrode already modified with carbon nanofibers and gold nanoparticles, by the drop-and-dry technique. The electrochemical properties of the three electrodes were studied by cyclic voltammetry in electroactive solutions, and the position and shape of the active redox peaks are according to the nature of the materials modifying the electrodes. In the case of ferulic acid, a series of characteristic peaks were observed, the processes being more intense for the biosensor, with the higher sensitivity and selectivity being due to the immobilization of tyrosinase, a specific enzyme for phenolic compounds. The calibration curve was subsequently created using CNF-GNP-Ty/SPE in ferulic acid solutions of various concentrations in the range 0.1-129.6 μM. This new biosensor allowed low values of the detection threshold and quantification limit, 2.89 × 10 mol·L and 9.64 × 10 mol·L, respectively, which shows that the electroanalytical method is feasible for quantifying ferulic acid in real samples. The ferulic acid was quantitatively determined in three cosmetic products by means of the CNF-GNP-Ty/SPE biosensor. The results obtained were validated by means of the spectrometric method in the infrared range, the differences between the values of the ferulic acid concentrations obtained by the two methods being under 5%.
本文研究了三种基于修饰丝网印刷电极（SPE）的传感器的电化学行为：一种基于碳纤维纳米纤维（CNF/SPE）的传感器、一种基于碳纳米纤维修饰金纳米粒子的传感器（CNF-GNP/SPE）和一种基于碳纳米纤维修饰金纳米粒子和酪氨酸酶的生物传感器（CNF-GNP-Ty/SPE）。为了制备生物传感器，通过滴涂-干燥技术将酪氨酸酶（Ty）固定在已经用碳纳米纤维和金纳米粒子修饰的电极表面上。通过在电化学活性溶液中进行循环伏安法研究了三个电极的电化学性质，并且活性氧化还原峰的位置和形状取决于修饰电极的材料的性质。在阿魏酸的情况下，观察到一系列特征峰，生物传感器的过程更为强烈，由于固定化酪氨酸酶，即酚类化合物的特定酶，具有更高的灵敏度和选择性。随后使用 CNF-GNP-Ty/SPE 在 0.1-129.6 μM 范围内的各种浓度的阿魏酸溶液中创建校准曲线。该新型生物传感器允许检测限和定量限的低值，分别为 2.89×10-9 mol·L-1 和 9.64×10-9 mol·L-1，这表明电分析方法可用于定量测定真实样品中的阿魏酸。通过 CNF-GNP-Ty/SPE 生物传感器定量测定了三种化妆品产品中的阿魏酸。通过在红外范围内的光谱方法验证了结果，两种方法获得的阿魏酸浓度值之间的差异小于 5%。
