Additive Manufacturing towards the Fabrication of Greener Electrochemical Sensors for Antioxidants

Additive manufacturing is an emerging tool that has contributed to the sustainable fabrication of devices in several areas based on the concept of “zero waste”. Considering extrusion-based manufacturing (or 3D printing), polylactic acid (PLA) has been highlighted due to its biodegradability, obtention from renewable sources, and compatibility for 3D printing. Composites of PLA with conducting fillers, such as carbon-black (CB/PLA), are commercially-available and compatible with extrusion-based 3D printers and 3D pen. Herein, we investigate the electrochemical behavior of several antioxidant species (catechol, hydroquinone, propyl-gallate, octyl-gallate, dopamine, gallic acid and pyrogallol (PY)) on 3D-printed electrodes. Experiments by cyclic voltammetry demonstrated that electrochemical surface treatment in NaOH aqueous solution is an important strategy to improve the response of all antioxidants. Thus, PY was selected to evaluate the analytical performance of the proposed 3D-printed sensor. For this, a fast and simple method using batch-injection analysis with amperometric detection (BIA-AD) has been developed, which showed a limit of detection of 0.15 µmol L-1, wide linear range (0.5 to 300 µmol L-1), good precision (relative standard deviation (RSD) < 3.4%) and selectivity. This method was applied in biodiesel samples, after dilution (400-fold) in electrolyte. Recovery percentages ranging from 82 to 119% attested absence of matrix effect and good accuracy.

增材制造（Additive manufacturing）是一种新兴技术，基于“零浪费”理念，已在多个领域推动了器件的可持续制备。以基于挤出的成型制造（或称3D打印）为例，聚乳酸（PLA）因具备可生物降解性、可再生来源特性以及与3D打印的良好兼容性而备受关注。聚乳酸与导电填料（如炭黑，CB/PLA）的复合材料已实现商业化，且适配基于挤出的3D打印机与3D笔。本文中，我们研究了多种抗氧化成分（儿茶酚、对苯二酚、没食子酸丙酯、没食子酸辛酯、多巴胺、没食子酸与焦性没食子酸（PY））在3D打印电极上的电化学行为。循环伏安法实验表明，在氢氧化钠水溶液中进行电化学表面处理，是提升所有抗氧化成分检测响应的重要策略。据此，我们选取焦性没食子酸（PY）来评估所制备的3D打印传感器的分析性能。为此，我们开发了一种快速简便的批量注射分析-安培检测法（BIA-AD），该方法的检出限为0.15 µmol L⁻¹，线性范围宽（0.5 至 300 µmol L⁻¹），精密度良好（相对标准偏差（RSD）< 3.4%）且选择性优异。该方法经电解质中400倍稀释后，应用于生物柴油样品的检测，回收率介于82%至119%之间，证实了无基质效应且准确度良好。