High-performance electrochemical sensor based on molecularly imprinted polypyrrole-graphene modified glassy carbon electrode

Molecularly imprinted polymers are pushing the limits of sensing capabilities in electrochemical sensors. As a result, these sensors are driving the improvement of chemical species detection with applications in pharmaceutical, chemical and food industries as well as showing potential for bioanalytes sensing for applications in medical diagnostics. In particular, molecularly imprinted polymer-graphene sensors have great potential to increase the selectivity, sensitivity and detectability of electrochemical sensors for organic molecules determination, especially in the presence of interferers. In this work, we tested three different coatings on glassy carbon electrode for the purpose of ascorbic acid quantification: graphene, molecular imprinted polypyrrole-graphene and non-imprinted polypyrrole-graphene. Among the prepared electrodes, non-imprinted and molecularly imprinted polypyrrole on graphene, exhibited the highest sensitivity to ascorbic acid (6.14 and 5.87 mu A/mmol L-1, respectively), although their detection limit (0.56 and 0.10 mmol L-1, respectively) was poore than the uncoated graphene one (0.02 mmol L-1). Besides that, graphene modified glassy carbon electrode showed better response for repetitive uses. However, in the case of a unique measurement to detect the presence of ascorbic acid in a solution containing interferers, as uric acid and dopamine, molecular imprinted polypyrrole-graphene electrode exhibits better response and selectivity in addition to, an electrocatalytic effect.