A self-assembled electrochemical immunosensor for ultra-sensitive detection of ochratoxin A in medicinal and edible malt. (15th June 2020)

• Record Type: Journal Article
• Authors: Sun, Chaonan; Liao, Xiaofang; Huang, Pinxuan; Shan, Guangzhi; Ma, Xiao; Fu, Lizhu; Zhou, Lidong; Kong, Weijun
• Is Part Of: Food chemistry. Volume 315(2020)
• Publication Date: 2020-06-15
• Subjects: Malt -- Ochratoxin A -- Electrochemical immunosensor -- Self-assembled monolayer -- Electrochemical impedance spectroscopy -- Differential pulse voltammetry; Food -- Analysis -- Periodicals; Food -- Composition -- Periodicals; 664
• DOI: 10.1016/j.foodchem.2020.126289
• Languages: English
• ISSNs: 0308-8146

Abstract

Highlights: A self-assembled electrochemical immunosensor was fabricated for determining OTA. TGA monolayer modified Au electrode could improve electrochemical response. Some crucial parameters were systematically optimized for improving the sensitivity and reliability. A ultra-low limit of detection of 0.08 ng/mL was obtained. Real application in real spiked malt samples with OTA explored high accuracy without matrix interferences. Abstract: Trace residue of mycotoxins in complex medicinal and edible food matrices has brought huge challenges for the development of ultrasensitive analytical methods. Here, a green electrochemical immunosensor for the ultrasensitive detection of ochratoxin A (OTA) was fabricated by self-assembling a compact 2-mercaptoacetic (TGA) monolayer on the surface of the working Au electrode to form the Au/TGA/bovine serum aibumin (BSA)-OTA/anti-OTA monoclonal antibody composite probes for selective and ultra-sensitive detection of OTA based on indirect competitive principle and differential pulse voltammetry analysis. The electrochemical impedance spectroscopy and cyclic voltammetry methods were introduced to characterize the assemble situation of the TGA-modified Au electrode and optimize some critical parameters for the green electrochemical immunoseonsor. Under the optimal conditions, the developed immunosensor exhibited much lower limit of detection (0.08 ng/mL) in the range of 0.1–1.0 ng/mL for OTA compared with other direct or disposable electrochemical immunosensors. Real application in the spiked malt samples verified high accuracy with no matrix interferences of the proposed immunoseonsor. This is a meaningful study on a self-assembled electrochemical immunoseonsor for ultra-sensitive and rapid detection of OTA in malt samples, which suggested a general simple-to-use sensing platform and prospect as an economical and green tool for ultra-sensitive detection of much more trace-level of toxic small molecules in other complex matrices to ensure their quality and safety.