Simple voltammetric analyses of ochratoxin A in food samples using highly-stable and anti-fouling black phosphorene nanosensor

Abstract

There are few reports on the electrochemical detection of ochratoxin A (OTA) using chemically modified electrode owing to the OTA poor electrochemical activity and strong fouling effect towards electrode surface. In this study, a novel nanosensor based on two-dimensional (2D) layered black phosphorene (BP) was successfully developed for the simple voltammetric detection of OTA in grape juice and red wine samples. The BP modified nanosensor showed a good linear electrochemical response towards OTA in a concentration range of 0.3–10 μg/mL with a detection limit of 0.18 μg/mL (S/N = 3) under the optimal conditions. A mechanism for the electrocatalytic oxidation of OTA was proposed and verified by density functional theory calculations that the oxidation of OTA is an irreversible electrochemical response with an adsorption-controlled process, and the nitrogen atom of the amide is oxidized to N+O− with two protons and two electrons. The proposed electrochemical sensor demonstrated good electrochemical stability, superior anti-fouling property and excellent sensitivity towards OTA detection. A satisfactory practicability with recoveries between 98.8% and 103.3% was obtained in real samples determination. This work puts forward a new sensing platform based on the two-dimensional layered graphene-like nanosensor for the electrochemical determination of mycotoxins in edible agricultural food.