Electrochemical non-enzymatic sensing of glycoside toxins by boronic acid functionalized nano-composites on screen-printed electrode

Abstract

Natural glycoside toxins, one of the most ubiquitous toxins in food of plant origin, cause serious health threat on humans and livestock. Evaluation of their health risk is of great significance. We proposed a non-enzymatic sensor based on reduced graphene oxide/gold nanoparticles/boronic acid nano-composites for their rapid and simple detection. The nano-composites were integrally synthesized in liquid dispersion. Gold nanoparticles, which were reduced from chloroauric acid, nucleated and grew on graphene oxide films directly. 4-mercaptophenylboronic acid self-assembled with gold nanoparticles through gold-sulfur bond. With reduction of graphene oxide through cyclic voltammetry, the nano-composites were then one step modified onto the working electrodes as sensing layer. Glycoalkaloids, common glycoside toxins in potatoes, were detected with the functionalized screen-printed electrodes. Electrochemical differential pulse voltammetry was applied for the detection. The sensor exhibited good stability in at least four weeks with a wide detection range from 10 μM to 1000 μM. The limit of detection was as low as 3.4 μM. The developed sensor was successfully applied to the detection of glycoalkaloids in real potato samples. As a proof of concept, the disposable sensor with high sensitivity and selectivity exhibited great application potential for the risk control of natural glycoside toxins in food.