Department of Analytical Chemistry and Chemical Engineering, University of Alcalá, Madrid, Spain.
Anal Bioanal Chem. 2012 Jan;402(2):945-53. doi: 10.1007/s00216-011-5453-x. Epub 2011 Oct 15.
The electrochemical detection of sugars is favored by the electrocatalytic effects of copper and nickel, which allow their detection with high sensitivity and without the need for derivatization. Also, novel nanotechnological tools known as metallic nanowires (NWs) may offer new possibilities for sensing, since their large active surfaces allow greatly enhanced sensitivity. In this work, nickel (NiNWs) and nickel-copper (Ni-CuNWs 50:50 w/w) nanowires were synthesized by electroplating using an alumina template, and characterized by scanning electronic microscopy (SEM), transmission electronic microscopy (TEM), and energy-dispersive X-ray spectrometry (EDS). Using an alumina template of 200 nm, and under the controlled deposition of 45 C of charge, both of these NWs were obtained with lengths of about 7 μm and widths of about 300 μm. EDS analysis confirmed that the percentage of Ni in the NiNWs was 97%, and the percentages of Ni and Cu in the Ni-CuNWs were 50.6% and 49.4%, respectively. Both of the electrosynthesized NW exhibited enhanced electrocatalytic properties (and therefore improved detection sensitivity) toward the target sugars. Analytical performance was then evaluated by analyzing ten target honeys, utilizing a simplified calibration strategy that employed a glucose:fructose mixture as the standard. Repeatability was excellent when calibration (RSDs ≤ 5%) and sample analysis (RSDs ≤ 6%) protocols were performed. The total sugar content obtained by the electrochemical approach was compared with that obtained using a HPLC-RI (refractive index) method. The novel method gave low systematic errors, revealing that it afforded very accurate results. Also, a high throughput was achieved, as 60 samples were processed in about 25 min (yielding a rate of 2 samples min(-1)) on a board containing just one electrode, without any loss of performance. While both electrosynthesized NWs exhibited good analytical performance, the NiNWs were judged to be the most suitable for use in a sensor because of their easy preparation, stability, and magnetic properties. Nanowire-based disposable screen-printed detectors that are strategically connected to miniaturized instrumentation represent a novel approach that could be used in standard labs.
电化学检测糖的方法得益于铜和镍的电催化作用，这使得它们能够以高灵敏度进行检测，而无需衍生化。此外，被称为金属纳米线 (NWs) 的新型纳米技术工具可能为传感提供新的可能性，因为它们的大表面积允许大大提高灵敏度。在这项工作中，通过使用氧化铝模板进行电镀合成了镍 (NiNWs) 和镍铜 (Ni-CuNWs 50:50 w/w) 纳米线，并通过扫描电子显微镜 (SEM)、透射电子显微镜 (TEM) 和能量色散 X 射线光谱 (EDS) 进行了表征。使用 200nm 的氧化铝模板，并在 45C 的受控沉积下，这两种 NW 都获得了约 7μm 的长度和约 300μm 的宽度。EDS 分析证实，NiNWs 中 Ni 的百分比为 97%，Ni-CuNWs 中 Ni 和 Cu 的百分比分别为 50.6%和 49.4%。这两种电合成的 NW 都表现出对目标糖的增强电催化性能（因此提高了检测灵敏度）。然后通过分析十种目标蜂蜜来评估分析性能，使用简化的校准策略，该策略采用葡萄糖：果糖混合物作为标准。当执行校准（RSDs≤5%）和样品分析（RSDs≤6%）方案时，重复性非常好。电化学方法获得的总糖含量与使用 HPLC-RI（折射率）方法获得的总糖含量进行了比较。新方法的系统误差较低，表明结果非常准确。此外，在一块仅包含一个电极的电路板上，在约 25 分钟内处理了 60 个样本（达到 2 个样本 min(-1)的速率），实现了高通量，而不会降低性能。虽然两种电合成的 NW 都表现出良好的分析性能，但由于其易于制备、稳定性和磁性，NiNWs 被认为更适合用于传感器。策略性连接到小型化仪器的基于纳米线的一次性丝网印刷探测器代表了一种新的方法，可用于标准实验室。
