Physiological level and selective electrochemical sensing of dopamine by a solution processable graphene and its enhanced sensing property in general

Herein, for the first time, mechanically pulverized graphite (pGr) has been used as an electrode material for the electrochemical (EC) sensing of analytes such as dopamine (DA) and ascorbic acid (AA). The pGr modified electrode exhibits a wide linear response range over the physiological concentration range of DA and AA, and the lowest limiting value of detection (LOD) so far reported for DA and AA of 1 nM, subjected to S/N = 3. The PGr demonstrates selectivity towards DA in the presence of AA and is able to simultaneously detect DA, AA and uric acid (UA). The enhanced and selective sensing of pGr towards DA is assigned to its intact aromatic basal plane structure which promotes the preferential adsorption of DA due to the similarities in their structures. The dispersibility of pGr in water and the formation of Gr nanosheets are explained by the hydrophilic edges. The sensing performance of pGr towards DA and AA is found to be superior to that of reduced graphene oxide (rGO) and graphene oxide (GO). Our results demonstrate the feasibility and the merits of pGr in the EC sensing applications and give insight to its structure. (C) 2017 Elsevier B.V. All rights reserved.