Center for Research on Electroanalysis (NuPE), Institute of Chemistry, Federal University of Uberlândia, 38408-100, Uberlândia, MG, Brazil.
Center for Research on Electroanalysis (NuPE), Institute of Chemistry, Federal University of Uberlândia, 38408-100, Uberlândia, MG, Brazil.
Anal Chim Acta. 2020 Oct 2;1132:10-19. doi: 10.1016/j.aca.2020.07.034. Epub 2020 Jul 30.
The fabrication of carbon black/polylactic acid (PLA) electrodes using a 3D printing pen is presented and compared with electrodes obtained by a desktop fused deposition modelling (FDM) 3D printer. The 3D pen was used for the fast production of electrodes in two designs using customized 3D printed parts to act as template and guide the reproducible application of the 3D pen: (i) a single working electrode at the bottom of a 3D-printed cylindrical body and (ii) a three-electrode system on a 3D-printed planar substrate. Both devices were electrochemically characterized using the redox probe [Fe(CN)] via cyclic voltammetry, which presented similar performance to an FDM 3D-printed electrode or a commercial screen-printed carbon electrode (SPE) regarding peak-to-peak separation (ΔEp) and current density. The surface treatment of the carbon black/PLA electrodes fabricated by both 3D pen and FDM 3D-printing procedures provided substantial improvement of the electrochemical activity by removing excess of PLA, which was confirmed by scanning electron microscopic images for electrodes fabricated by both procedures. Structural defects were not inserted after the electrochemical treatment as shown by Raman spectra (i/i), which indicates that the use of 3D pen can replace desktop 3D printers for electrode fabrication. Inter-electrode precision for the best device fabricated using the 3D pen (three-electrode system) was 4% (n = 5) considering current density and anodic peak potential for the redox probe. This device was applied for the detection of 2,4,6-trinitrotoluene (TNT) via square-wave voltammetry of a single-drop of 100 μL placed upon the thee-electrode system, resulting in three reduction peaks commonly verified for TNT on carbon electrodes. Limit of detection of 1.5 μmol L, linear range from 5 to 500 μmol L and RSD lower than 4% for 10 repetitive measurements of 100 μmol L TNT were obtained. The proposed devices can be reused after polishing on sandpaper generating new electrode surfaces, which is an extra advantage over chemically-modified electrochemical sensors applied for TNT detection.
使用 3D 打印笔制造碳黑/聚乳酸 (PLA) 电极，并将其与桌面熔融沉积建模 (FDM) 3D 打印机制造的电极进行比较。3D 打印笔用于快速生产两种设计的电极，使用定制的 3D 打印零件作为模板，引导 3D 打印笔可重复应用：(i) 在 3D 打印圆柱形主体底部的单个工作电极，以及 (ii) 在 3D 打印平面基板上的三电极系统。这两种装置均通过循环伏安法使用氧化还原探针 [Fe(CN)] 进行电化学表征，其峰-峰分离 (ΔEp) 和电流密度与 FDM 3D 打印电极或商业丝网印刷碳电极 (SPE) 相似。通过扫描电子显微镜图像证实，通过去除过量 PLA，对由 3D 笔和 FDM 3D 打印工艺制造的碳黑/PLA 电极进行表面处理可显著提高电化学活性。由拉曼光谱 (i/i) 证实，在电化学处理后没有插入结构缺陷，这表明 3D 笔的使用可以替代桌面 3D 打印机进行电极制造。使用 3D 笔制造的最佳装置 (三电极系统) 的电极间精度为 4% (n = 5)，考虑到电流密度和氧化还原探针的阳极峰电位。通过在三电极系统上放置 100 μL 一滴单滴进行方波伏安法，该装置可用于检测 2,4,6-三硝基甲苯 (TNT)，导致在碳电极上通常验证 TNT 的三个还原峰。获得了 1.5 μmol L 的检测限、5 至 500 μmol L 的线性范围以及 100 μmol L TNT 重复测量 10 次的 RSD 低于 4%。通过在砂纸上抛光，可以对这些装置进行再利用，从而产生新的电极表面，这是与用于 TNT 检测的化学修饰电化学传感器相比的额外优势。
