AbstractA novel photoelectrochemical (PEC) aptasensor with graphitic-phase carbon nitride quantum dots (g-C3N4; QDs) and reduced graphene oxide (rGO) was fabricated. The g-C3N4 QDs possess enhanced emission quantum yield (with an emission peak at 450 nm), improved charge separation ability and effective optical absorption, while rGO has excellent electron transfer capability. Altogether, this results in improved PEC performance. The method is making use of an aptamer against sulfadimethoxine (SDM) that was immobilized on electrode through π stacking interaction. Changes of the photocurrent occur because SDM as a photogenerated hole acceptor can further accelerate the separation of photoexcited carriers. Under optimized conditions and at an applied potential of +0.2 V, the aptasensor has a linear response in the 0.5 nM to 80 nM SDM concentration range, with a 0.1 nM detection limit (at S/N = 3). The method was successfully applied to the analysis of SDM in tap, lake and waste water samples. Graphical abstractGraphitic-phase carbon nitride (g-C3N4) quantum dots (QDs) and reduced graphene oxide (rGO) were used to modify fluorine-doped SnO2 (FTO) electrodes for use in a photoelectrochemical (PEC) aptasensor. SDM oxidized by the hole on valance band (VB) of g-C3N4 QDs promote the separation of electron in the conductive band (CB), which made the changes of photocurrent signal.

中文翻译：

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使用还原氧化石墨烯修饰的 g-C3N4 量子点的磺胺二甲氧嘧啶光电化学适体传感器

摘要 制备了一种具有石墨相氮化碳量子点 (g-C3N4; QDs) 和还原氧化石墨烯 (rGO) 的新型光电化学 (PEC) 适体传感器。g-C3N4 QDs 具有增强的发射量子产率（发射峰位于 450 nm）、改进的电荷分离能力和有效的光吸收，而 rGO 具有出色的电子转移能力。总之，这会提高 PEC 性能。该方法是利用通过 π 堆积相互作用固定在电极上的针对磺胺二甲氧嘧啶 (SDM) 的适体。光电流发生变化是因为 SDM 作为光生空穴受体可以进一步加速光激发载流子的分离。在优化条件和 +0.2 V 的外加电位下，适体传感器在 0.0 范围内具有线性响应。5 nM 至 80 nM SDM 浓度范围，检测限为 0.1 nM（S/N = 3）。该方法已成功应用于自来水、湖泊和废水样品中 SDM 的分析。图形摘要石墨相氮化碳 (g-C3N4) 量子点 (QD) 和还原氧化石墨烯 (rGO) 用于修饰掺氟 SnO2 (FTO) 电极，用于光电化学 (PEC) 适体传感器。被g-C3N4量子点的价带（VB）上的空穴氧化的SDM促进了导电带（CB）中电子的分离，从而引起了光电流信号的变化。图形摘要石墨相氮化碳 (g-C3N4) 量子点 (QD) 和还原氧化石墨烯 (rGO) 用于修饰掺氟 SnO2 (FTO) 电极，用于光电化学 (PEC) 适体传感器。被g-C3N4量子点的价带（VB）上的空穴氧化的SDM促进了导电带（CB）中电子的分离，从而引起了光电流信号的变化。图形摘要石墨相氮化碳 (g-C3N4) 量子点 (QD) 和还原氧化石墨烯 (rGO) 用于修饰掺氟 SnO2 (FTO) 电极，用于光电化学 (PEC) 适体传感器。被g-C3N4量子点的价带（VB）上的空穴氧化的SDM促进了导电带（CB）中电子的分离，从而引起了光电流信号的变化。