Development of impedimetric aptasensor based on polyaniline for aflatoxin B1 detection in foodstuffs and feedstuffs for food safety

Abstract

The growing demand for poultry meats and eggs has intensified the poultry production driven by the rapid global population growth over the years. However, the presence of natural mycotoxin contaminants, such as aflatoxins, ochratoxin A, and zearalenone are detected in the foodstuffs and feedstuffs from farm poultry by researcher, which is a serious concern for human health. The detection of mycotoxins is therefore necessary as a preventive action to avoid the harmful contamination of foodstuffs and animal feed. In comparison to the considerable expense of treating contaminated foodstuffs and feedstuffs, early detection is a cost-effective way to ensure food safety. Herein, an impedimetric aptasensor based on polyaniline (PAni) support matrix is developed through the surface modification of screen-printed carbon electrode (SPE) for aflatoxin B1 (AFB1) detection in foodstuffs and feedstuffs for food safety. The PAni is synthesised with chemical oxidation method and characterised with potentiostat/galvanostat, FTIR and UV-vis spectroscopy techniques. The stepwise fabrication procedure of the fabricated PAni-based aptasensor is characterised by means of Cyclic Voltammetry (CV) and Electrochemical Impedance Spectroscopy (EIS) electrochemical methods. The impedimetric aptasensor is optimised using EIS technique and its feasibility of detecting AFB1 in real sample matrices is evaluated via recovery study in spiked foodstuffs and feedstuffs, such as pistachio nuts, cinnamons, cloves, corn and soybeans with a good recovery percentage ranging from 87.9% to 94.7%. The charge transfer resistance (RCT) of the aptasensor increases linearly with the AFB1 concentration in the range of 3×10-2

nM to 8×10-2

nM with a regression

coefficient (R2

) value of 0.9991 and detection limit of 0.01 nM. The proposed aptasensor is highly selective towards AFB1 and partially selective to AFB2 and OTA due to their similar structures that differ only on the carbon-carbon double bond located at C8 and C9 and large molecule size of OTA. The aptasensor is stable up to 5 days of storage period at 4 °C and exhibits an optimised response time of 30 min. Repeatability of the aptasensor for four AFB1 detection cycles is good with RSD value lower than 5% (n=4). Besides the use of aptasensor as a monitoring technique for mycotoxin surveillance and mitigation, the implementation of feasible provisions and extensive research are crucial as a part of the approach to mitigate mycotoxin in foodstuffs and feedstuffs.