Abstract Ochratoxin A (OTA), a widespread food contaminant, is considered as one of the most hazardous mycotoxins commonly occurring in beer. Herein, we describe a novel impedimetric aptasensor based on Pencil Graphite Electrodes (PGE) for the analysis of OTA. Taking advantage of its affordability and high active surface area, a PGE was modified with a specific aptamer, to achieve sensitive detection of OTA. This strategy relies on the target-induced increase in the electron transfer resistance (Rct) upon OTA recognition using ferro/ferricyanide as a redox probe. With the addition of OTA, the formation of OTA–aptamer complex resulted in an increase of Rct. The change of Rct strongly depends on OTA concentration, which is applied for mycotoxin quantification. An acceptable linear range was obtained from 0.1 to 2.0 ng mL−1 with a very good limit of detection as low as 0,1 ng mL−1. This simple-to-design aptasensor was successfully tested in spiked beer samples, with OTA concentrations in the range of 0.4–1.6 ng mL−1, attesting a recovery percentage of 93.4 ± 6.6%. It also showed a high level of stability and reproducibility thanks to the electro-grafting method via in-situ generation of 4-carboxyphenyl diazonium salts. This PGE-based platform is a versatile approach for the design of low-cost aptasensors for food safety control.

中文翻译：

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适体修饰的铅笔石墨电极，用于赭曲霉毒素 A 的阻抗测定

摘要 Ochratoxin A (OTA) 是一种广泛存在的食品污染物，被认为是啤酒中常见的最危险的霉菌毒素之一。在此，我们描述了一种基于铅笔石墨电极 (PGE) 的新型阻抗适体传感器，用于分析 OTA。利用其经济性和高活性表面积的优势，用特定的适体修饰 PGE，以实现对 OTA 的灵敏检测。该策略依赖于使用亚铁/铁氰化物作为氧化还原探针的 OTA 识别时目标诱导的电子转移电阻 (Rct) 增加。随着OTA的加入，OTA-适配体复合物的形成导致Rct增加。Rct 的变化很大程度上取决于 OTA 浓度，该浓度适用于真菌毒素定量。从 0.1 到 2 获得了可接受的线性范围。0 ng mL-1，检测限低至 0.1 ng mL-1。这种设计简单的适体传感器已在加标啤酒样品中成功测试，OTA 浓度范围为 0.4–1.6 ng mL-1，证明回收率为 93.4 ± 6.6%。由于通过原位生成 4-羧基苯基重氮盐的电接枝方法，它还显示出高度的稳定性和重现性。这种基于 PGE 的平台是设计用于食品安全控制的低成本适体传感器的通用方法。由于通过原位生成 4-羧基苯基重氮盐的电接枝方法，它还显示出高度的稳定性和重现性。这种基于 PGE 的平台是设计用于食品安全控制的低成本适体传感器的通用方法。由于通过原位生成 4-羧基苯基重氮盐的电接枝方法，它还显示出高度的稳定性和重现性。这种基于 PGE 的平台是设计用于食品安全控制的低成本适体传感器的通用方法。