Ankara University, Faculty of Pharmacy, Department of Analytical Chemistry, 06560, Ankara, Turkey; Electroanalytical Chemistry Laboratory, Department of Chemistry, Faculty of Sciences, Azarbaijan Shahid Madani University, Tabriz, Iran.
University of Health Science, Gulhane Faculty of Pharmacy, Department of Analytical Chemistry, Corum, Turkey.
J Pharm Biomed Anal. 2020 Mar 20;181:113096. doi: 10.1016/j.jpba.2020.113096. Epub 2020 Jan 3.
In this study, a novel and sensitive nanocomposite of carboxylate-functionalized multiwalled carbon nanotube (COOH-fMWCNT) and silver nanoparticles (AgNPs) was fabricated and used to modify a glassy carbon electrode (GCE) by a simple drop casting method. Modified electrode was then applied for selective determination of emedastine difumarate (EDD). The COOH-fMWCNT/AgNPs nanocomposite was characterized by electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX) and cyclic voltammetry (CV). EDD showed two oxidation peaks at 0.634 and 1.2 V on the GCE surface. CV results of COOH-fMWCNT/AgNPs/GCE displayed superior electrocatalytic performance in terms of anodic peak current of EDD when compared to AgNPs/GCE, MWCNT/GCE, and COOH-fMWCNT/GCE. The experimental conditions such as effect of pH, supporting electrolyte, effect of accumulation time and potential, scan rate were optimized for getting intense current signals of the target analyte. Under optimized conditions, COOH-fMWCNT/AgNPs/GCE showed a linear current response for oxidation of EDD in the range of 1.0 × 10-1.0 × 10 M, with a limit of detection (LOD) and quantification (LOQ) of 5.25 nM, 15.9 nM, respectively, in 0.1 M phosphate buffer solution at pH 2.0 using differential pulse adsorptive stripping voltammetry technique. The proposed method was successfully applied for determination of EDD in pharmaceutical dosage form. Satisfactory recovery percentages were achieved from eye drop sample with acceptable RSD values (less than 2 %). Furthermore, the reproducibility, stability and repeatability of the modified electrode were studied.
在这项研究中，制备了一种新型的、灵敏的羧基功能化多壁碳纳米管（COOH-fMWCNT）和银纳米粒子（AgNPs）纳米复合材料，并通过简单的滴铸法将其修饰到玻碳电极（GCE）上。然后，将修饰后的电极用于选择性测定依美斯汀富马酸盐（EDD）。COOH-fMWCNT/AgNPs 纳米复合材料通过电化学阻抗谱（EIS）、扫描电子显微镜（SEM）、能谱（EDX）和循环伏安法（CV）进行了表征。EDD 在 GCE 表面显示出两个氧化峰，分别为 0.634 和 1.2 V。与 AgNPs/GCE、MWCNT/GCE 和 COOH-fMWCNT/GCE 相比，COOH-fMWCNT/AgNPs/GCE 的 CV 结果显示出 EDD 的阳极峰电流具有更好的电催化性能。优化了实验条件，如 pH 值、支持电解质、积累时间和电位、扫描速率等，以获得目标分析物的强烈电流信号。在优化条件下，COOH-fMWCNT/AgNPs/GCE 在 1.0×10-1.0×10 M 范围内对 EDD 的氧化呈现出线性电流响应，在 pH 2.0 的 0.1 M 磷酸盐缓冲溶液中，检测限（LOD）和定量限（LOQ）分别为 5.25 nM 和 15.9 nM，采用差分脉冲吸附溶出伏安法技术。该方法成功应用于药物制剂中 EDD 的测定。从滴眼剂样品中获得了令人满意的回收率，并且 RSD 值（小于 2%）可接受。此外，还研究了修饰电极的重现性、稳定性和重复性。
