Department of Physical and Environmental Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, ON M1C 1A4, Canada.
Department of Physical and Environmental Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, ON M1C 1A4, Canada.
Mater Sci Eng C Mater Biol Appl. 2020 May;110:110568. doi: 10.1016/j.msec.2019.110568. Epub 2019 Dec 19.
In this proof-of-concept study, a thiol-functionalized sol-gel-based carbon ceramic electrode (CCE) was developed. This CCE was further modified by immobilizing gold nanoparticles (AuNP) in the thiol-functionalized ceramic matrix as well as incorporating multi-walled carbon nanotubes (MWCNT) within the pores of this ceramic sol-gel. The proposed electrode (MWCNT-AuNP-CCE) was used for the simultaneous determination of purine derivatives, uric acid (UA), xanthine (XA) and caffeine (CA). The simultaneous detection of these compounds is essential because these purine derivatives often coexist in real samples. Moreover, since these analytes have the capacity to interchange structures, developing a simultaneous detector is important. This electrode was successfully characterized using environmental scanning electron microscopy (ESEM) with secondary and back scattering electron detectors, energy dispersive X-ray (EDX) analysis, transmission electron microscopy (TEM), and Fourier-transform infrared (FT-IR) spectroscopy. Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) measurements were performed in phosphate buffer solution (0.1 M PBS, pH 6) at a potential window of 0.2 to 1.1 V (vs. Ag/AgCl). The proposed modified electrode (MWCNT-AuNP-CCE) displayed three well-defined, stable and continuous oxidation peaks at 0.3, 0.7 and 1.0 V for UA, XA, and CA, respectively. The resulting catalytic current at the surfaces showed a linear dependence to the concentrations of UA, XA and CA for up to 225, 225 and 1500 μM, respectively. The limit of detection was determined to be 50, 63 and 354 nM for UA, XA and CA, respectively. The analytical performance of MWCNT-AuNP-CCE was challenged with real samples such as human serum and urine with recoveries ranging between 98.1 and 102.6%. Moreover, the selectivity of sensor was further challenged with very similar purine molecules, theobromine and theophylline, which contain one less methyl group than CA. Overall, MWCNT-AuNP-CCE exhibited a promising platform for the future development of sensitive electrochemical sensors for the detection of purine derivatives in real samples.
在这项概念验证研究中，开发了一种巯基功能化溶胶-凝胶基碳陶瓷电极（CCE）。 该 CCE 进一步通过将金纳米粒子（AuNP）固定在巯基功能化陶瓷基质中以及将多壁碳纳米管（MWCNT）掺入陶瓷溶胶-凝胶的孔中来修饰。 所提出的电极（MWCNT-AuNP-CCE）用于同时测定嘌呤衍生物、尿酸（UA）、黄嘌呤（XA）和咖啡因（CA）。 同时检测这些化合物是必不可少的，因为这些嘌呤衍生物通常共存于实际样品中。 此外，由于这些分析物具有结构交换的能力，因此开发同时检测器很重要。 该电极使用环境扫描电子显微镜（ESEM）和二次电子和背散射电子探测器、能量色散 X 射线（EDX）分析、透射电子显微镜（TEM）和傅里叶变换红外（FT-IR）光谱进行了成功的表征。 在磷酸盐缓冲溶液（0.1 M PBS，pH 6）中，在 0.2 至 1.1 V（相对于 Ag/AgCl）的电位窗口下进行循环伏安法（CV）和差分脉冲伏安法（DPV）测量。 所提出的修饰电极（MWCNT-AuNP-CCE）在 0.3、0.7 和 1.0 V 处显示出三个定义明确、稳定和连续的氧化峰，分别用于 UA、XA 和 CA。 在表面处的所得催化电流对 UA、XA 和 CA 的浓度表现出线性依赖性，最高可达 225、225 和 1500 μM。 UA、XA 和 CA 的检测限分别确定为 50、63 和 354 nM。 MWCNT-AuNP-CCE 的分析性能受到人血清和尿液等实际样品的挑战，回收率在 98.1%至 102.6%之间。 此外，还使用含有 CA 少一个甲基的非常相似的嘌呤分子可可碱和茶碱进一步挑战了传感器的选择性。 总体而言，MWCNT-AuNP-CCE 为在实际样品中检测嘌呤衍生物的敏感电化学传感器的未来发展提供了一个有前途的平台。
