Dossi Nicolò, Petrazzi Stefano, Terzi Fabio, Toniolo Rosanna, Bontempelli Gino
Department of Agrifood, Environmental and Animal Science, University of Udine, via Cotonificio 108, I-33100 Udine, Italy.
Department of Agrifood, Environmental and Animal Science, University of Udine, via Cotonificio 108, I-33100 Udine, Italy.
Talanta. 2019 Jul 1;199:14-20. doi: 10.1016/j.talanta.2019.01.126. Epub 2019 Feb 10.
A simple, effective and low-cost technique is here presented for assembling flexible and robust electrochemical devices on transparent PVC supports, using ordinary tools, all installed on a commercial desktop digitally controlled plotter/cutter. Small diamond burs were first set up to rough precise and well defined patterns on the surface of smooth and flexible PVC transparent films. Subsequently, reference, counter and working carbon electrodes were drawn onto abraded patterns by using micropencils (4B graphite leads, 0.5 mm in diameter), in their turn installed on the plotter/cutter. The effective active working surface of electrochemical cells was then defined by a thin adhesive strip or by covering the patterned support with a suitably cut adhesive layer, depending upon whether they were intended for use in batch or drop mode. After optimization of fabrication parameters, such as pressure and speed adopted during bur abrasion and pencil drawing, the electrochemical characterization of these cells was performed by using potassium hexacyanoferrate(II) as redox probe. Voltammetric responses displayed a good inter-device reproducibility (5.6%), thus confirming the effectiveness of this easy and fast assembling strategy. These PVC-based pencil-drawn electrochemical cells were then integrated as thin-layer detectors in adhesive-tape based microfluidic channels, cut and prepared in their turn using the digitally controlled plotter/cutter. These detectors offer the advantage given by the impermeability of PVC supports, thus avoiding absorption of the flowing carrier and consequent analyte broadening, instead occurring when electrochemical cells are pencil drawn on hydrophilic materials as paper. After optimization of the complete fabrication process, the effectiveness of these devices was tested by a proof-of-concept direct quantification of ascorbic acid in commonly used drugs.
本文介绍了一种简单、有效且低成本的技术，可使用普通工具在透明PVC支架上组装灵活且坚固的电化学装置，所有工具均安装在商用桌面数控绘图仪/切割机上。首先使用小金刚石磨头在光滑且柔韧的PVC透明薄膜表面粗略加工出精确且轮廓清晰的图案。随后，使用微型铅笔（直径0.5毫米的4B石墨笔芯）在磨损的图案上绘制参比、对电极和工作碳电极，这些微型铅笔依次安装在绘图仪/切割机上。然后，根据电化学电池是打算用于批量模式还是滴加模式，通过一条细胶带或用适当切割的粘合剂层覆盖图案化的支架来确定电化学电池的有效活性工作表面。在优化诸如磨头磨损和铅笔绘图过程中采用的压力和速度等制造参数后，以亚铁氰化钾作为氧化还原探针对这些电池进行电化学表征。伏安响应显示出良好的器件间重现性（5.6%），从而证实了这种简便快速的组装策略的有效性。然后，将这些基于PVC的铅笔绘制电化学电池集成到基于胶带的微流控通道中作为薄层检测器，这些微流控通道同样使用数控绘图仪/切割机进行切割和制备。这些检测器具有PVC支架不渗透的优点，从而避免了流动载体的吸收以及随之而来的分析物展宽，而当在诸如纸等亲水材料上用铅笔绘制电化学电池时会出现这种情况。在优化整个制造过程后，通过对常用药物中抗坏血酸进行概念验证直接定量来测试这些装置的有效性。
