Abstract Herein, the paper developed a bimodal electrochemiluminescence (ECL) method based on dual-enhancement Ru(bpy)32+/CQDs/AA system combined with magnetic field enhanced solid-phase microextraction (MFE-SPME) for the direct determination of ascorbic acid (AA). The nanocomposite of Fe3O4@CS@GO, as a magnetic adsorbent, could efficiently extract AA under the external magnetic field provided by the magnetic glassy carbon electrode (MGCE) with the extraction efficiency up to 89.2%. Based on carbon quantum dots (CQDs) as the co-reactant for Ru(bpy)32+, when the potential was swept cyclically between −3.5 and 2.0 V, the bimodal ECL emissions were obtained in the Ru(bpy)32+/CQDs/AA system and were enhanced as AA concentration increased. The method could quantitatively detect AA, because the ln(ECL-1/ECL-2) of bimodal ECL system was in a good linear relationship with the negative logarithm of the AA concentration in the range of 10−5–10−9 M with the limit of detection (LOD, S/N = 3) of 330 pM. After a series of evaluations, the method exhibited good sensitivity, satisfactory repeatability and excellent anti-interference, demonstrating that the developed method had great application potential in analysis fields.

中文翻译：

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基于双增强Ru(bpy)32+/CQDs/AA体系结合磁场增强固相微萃取的双峰电化学发光方法直接测定抗坏血酸

摘要 本文开发了一种基于双增强 Ru(bpy)32+/CQDs/AA 系统结合磁场增强固相微萃取 (MFE-SPME) 直接测定抗坏血酸的双峰电化学发光 (ECL) 方法。 (AA)。Fe3O4@CS@GO纳米复合材料作为磁性吸附剂，可以在磁性玻碳电极（MGCE）提供的外部磁场下高效提取AA，提取效率高达89.2%。基于碳量子点 (CQDs) 作为 Ru(bpy)32+ 的共反应物，当电位在 -3.5 和 2.0 V 之间循环扫描时，在 Ru(bpy)32+/CQDs 中获得双峰 ECL 发射/AA 系统并随着 AA 浓度的增加而增强。该方法可以定量检测AA，因为双峰 ECL 系统的 ln(ECL-1/ECL-2) 与 AA 浓度在 10-5-10-9 M 范围内的负对数呈良好的线性关系，具有检测限 (LOD, S/N = 3) 330 pM。经过一系列的评估，该方法表现出良好的灵敏度、令人满意的重复性和优异的抗干扰性，表明该方法在分析领域具有很大的应用潜力。