Diazo-functionalised immunoelectrochemical sensor for the detection of ochratoxin a in foods

Abstract

Ochratoxin A (OTA) is a toxic fungal metabolite that is commonly found in cereals and animal feed. It is economically damaging and potentially hazardous to human health. Herein, we propose an electrochemical immunosensor for the rapid detection of OTA using anti-OTA antibodies and diazonium-functionalized, screen-printed electrodes. We attached 4-aminobenzoic acid to an electrode surface, activated the carboxyl groups on the surface with carbodiimide, and attached an antibody to the diazo layer. Subsequently, we used bovine serum protein as a blocker to prevent non-specific antigens from binding to the antibody. We evaluated the performance of the sensor by cyclic voltammetry, electrochemical impedance spectroscopy, and differential pulse voltammetry. The sensor is highly specific and sensitive, has good linear responses in the range 20–200 ng/mL, a limit of detection of 0.5 ng/mL, and good recoveries of 90.5%–100.9% in spiked samples. It can be stored at 4 °C for approximately 2 weeks, and is highly stable, with a current response variation of no more than 4.6%.

Keywords:

• Ochratoxin A
• electrochemistry
• screen-printed electrode
• diazotisation
• rapid food detection

Acknowledgments

We thank Frank Kitching, from Liwen Bianji (Edanz) (www.liwenbianji.cn) for editing the English text of a draft of this manuscript.

Author contributions

Investigation: Xin Wang; Formal analysis: Xin Wang, Xinyi Song; Methodology: Xin Wang, Xinyi Song, Xiaolei Zhao, Jinxing He; Resources: Xin Wang, Xinyi Song, Xiaolei Zhao, Jinxing He; Writing—original draft preparation: Xin Wang; Writing—review and editing: Xin Wang, Jinxing He; Funding acquisition: Jinxing He; Project administration: Jinxing He; Supervision: Jinxing He.

Compliance with ethics requirements

This article does not contain any studies with human participants or animals performed by any of the authors.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

The datasets generated and/or analysed during the current study are available from the corresponding author on reasonable request.

Additional information

Funding

This work was supported by the Shandong Provincial Natural Science Foundation, China [grant number ZR2021MC187], and the Key R&D Plan of Shandong Province (Major Science and Technology Innovation Project), China [grant number 2023CXGC010712].