Rageh Azza H, Said Mohamed I, Abdel-Aal Fatma A M
Department of Pharmaceutical Analytical Chemistry, Faculty of Pharmacy, Assiut University, Assiut, 71526, Egypt.
Department of Chemistry, Faculty of Science, Assiut University, Assiut, 71516, Egypt.
Mikrochim Acta. 2024 Apr 3;191(5):236. doi: 10.1007/s00604-024-06297-1.
Three different types of Zr-based MOFs derived from benzene dicarboxylic acid (BDC) and naphthalene dicarboxylic acid as organic linkers (ZrBDC, 2,6-ZrNDC, and 1,4-ZrNDC) were synthesized. They were characterized using X-ray diffraction analysis (XRD), X-ray photoelectron spectroscopy (XPS), Fourier-transform IR spectroscopy (FT-IR), and Transmission electron microscopy (TEM). Their hydrophilic/hydrophobic nature was investigated via contact angle measurements; ZrBDC MOF was hydrophilic and the other two (ZrNDC) MOFs were hydrophobic. The three MOFs were combined with MWCNTs as electrode modifiers for the determination of a hydrophobic analyte, flibanserin (FLB), as a proof-of-concept analyte. Under the optimized experimental conditions, a significant enhancement in the oxidation peak current of FLB was observed when utilizing 2,6-ZrNDC and 1,4-ZrNDC, being the highest when using 1,4-ZrNDC. Furthermore, a thorough investigation of the complex oxidation pathway of FLB was performed by carrying out simultaneous spectroelectrochemical measurements. Based on the obtained results, it was verified that the piperazine moiety of FLB is the primary site for electrochemical oxidation. The fabricated sensor based on 1,4-ZrNDC/MW/CPE showed an oxidation peak of FLB at 0.8 V vs Ag/AgCl. Moreover, it showed excellent linearity for the determination of FLB in the range 0.05 to 0.80 μmol L with a correlation coefficient (r) = 0.9973 and limit of detection of 3.0 nmol L. The applicability of the developed approach was demonstrated by determination of FLB in pharmaceutical tablets and human urine samples with acceptable repeatability (% RSD values were below 1.9% and 2.1%, respectively) and reasonable recovery values (ranged between 97 and 103% for pharmaceutical tablets and between 96 and 102% for human urine samples). The outcomes of the suggested methodology can be utilized for the determination of other hydrophobic compounds of pharmaceutical or biological interest with the aim of achieving low detection limits of these compounds in various matrices.
合成了三种不同类型的基于锆的金属有机框架材料，它们以苯二甲酸（BDC）和萘二甲酸作为有机连接体（ZrBDC、2,6-ZrNDC和1,4-ZrNDC）。使用X射线衍射分析（XRD）、X射线光电子能谱（XPS）、傅里叶变换红外光谱（FT-IR）和透射电子显微镜（TEM）对它们进行了表征。通过接触角测量研究了它们的亲水/疏水性质；ZrBDC金属有机框架材料是亲水的，另外两种（ZrNDC）金属有机框架材料是疏水的。将这三种金属有机框架材料与多壁碳纳米管结合作为电极修饰剂，用于测定疏水性分析物氟班色林（FLB），作为概念验证分析物。在优化的实验条件下，使用2,6-ZrNDC和1,4-ZrNDC时，观察到FLB的氧化峰电流有显著增强，使用1,4-ZrNDC时增强最为明显。此外，通过进行同步光谱电化学测量，对FLB复杂的氧化途径进行了深入研究。根据获得的结果，证实了FLB的哌嗪部分是电化学氧化的主要位点。基于1,4-ZrNDC/MW/CPE制备的传感器在相对于Ag/AgCl为0.8 V时显示出FLB的氧化峰。此外，它在0.05至0.80 μmol/L范围内对FLB的测定显示出良好的线性，相关系数（r）=0.9973，检测限为3.0 nmol/L。通过在药片中测定FLB和人尿液样品中测定FLB，证明了所开发方法的适用性，具有可接受的重复性（%RSD值分别低于1.9%和2.1%）和合理的回收率值（药片中回收率在97%至103%之间，人尿液样品中回收率在96%至102%之间）。所建议方法的结果可用于测定其他具有药物或生物学意义的疏水性化合物，目的是在各种基质中实现这些化合物的低检测限。
