Fabrication of a novel and high-performance amperometric sensor for highly sensitive determination of ochratoxin A in juice samples

摘要

In the present study, I fabricated a novel amperometric sensor based on step-by-step modification of the bare glassy carbon electrode (GCE) by graphene-multiwalled carbon nanotubes-chitosan-ionic liquid (Gr-MWCNTs-Ch-IL)/collagen-IL (CG-IL)/NiO nanoparticles (NiO NPs) for ultrasensitive determination of ochratoxin A (OTA) in juice samples. CG has a lot of oxygen and nitrogen atoms which enable it to have good affinity to metal oxide for stabilizing metal oxide NPs and avoiding their aggregation. The modifications applied to the bare GCE to construct the OTA sensor were characterized by electrochemical and microscopic methods. Then, the sensor was electroanalytically characterized by amperometric method towards OTA determination in synthetic samples and our records confirmed that the sensor was able to ultrasensitive determination of OTA in a concentration range of 0.01-10 nM with a limit of detection of 0.5 x 10(-11) M and a sensitivity of 36.4 mu A nM(-1). Finally, the sensor was successfully applied to determination of OTA in three different grape juice samples. The results of this study introduced a low-cost, sensitive, selective, fast, repeatable and reproducible OTA sensor which can be applied to the routine analysis of real samples towards OTA determination.