Bioreceptor-free, sensitive and rapid electrochemical detection of patulin fungal toxin, using a reduced graphene oxide@SnO2 nanocomposite.

In this research, we successfully synthesized a reduced graphene oxide/tin oxide (rGO/SnO2) composite for the electrochemical detection of fungal contaminant, patulin (PAT) that does not require a biological or chemical receptor or specific antibodies. The resulting rGO/SnO2 composite exhibited promising electrochemical properties and demonstrated outstanding performance in the direct measurement of PAT levels in contaminated apple juice samples. The differential pulse voltammetric response of the rGO/SnO2 composite electrode exhibited a linear relationship with PAT concentration in the 50-600 nM range and had a lower detection limit of 0.6635 nM. The sensor electrode exhibited high sensitivity, reliable reproducibility, and good selectivity. The designed electrochemical sensor was also tested against the time-consuming and conventional high-performance liquid chromatography (HPLC) approach for the detection of PAT in spiked apple juice samples. We found that the electrochemical sensor had ability to rapidly detect PAT in apple juice samples without the need of extraction or clean-up steps and achieved a higher recovery rate (74.33 ± 0.70 to 99.26 ± 0.70%) within a short-time analysis than did by the HPLC (61.97 ± 1.78 to 84.31 ± 1.96%), thus illustrating its feasibility for use in agricultural and food safety industries.