Rapid Selective Detection of Ascorbic Acid Using Graphene-Based Microfluidic Platform

Abstract

Ascorbic acid plays a significant role in human health by scavenging free radicals and consequently preventing cancer, rheumatoid arthritis, and neurodegenerative diseases. Here we present a compact microfluidic platform for selective detection of ascorbic acid. The microfluidic chip was fabricated by xurography technique with microfluidic channel placed between the silver electrodes. To increase the conductivity of the platform and enhance electron transfer process, a graphene sheet was deposited in the gap between the electrodes. The suspension of tablets with ascorbic acid and a mixture of ascorbic acid and isomalt, a sugar substitute, were injected into the microfluidic channel. Measuring electrical parameters at the silver contacts, it was possible to successfully differentiate ascorbic acid from isomalt. Electroimpedance spectroscopic analysis was performed, equivalent circuits suggested, and the sensing mechanism explained. The addition of graphene was found to improve the response linearity by 5.28% and lower the limit of detection and quantification by 12%, compared to the reference structure without graphene.