This paper reports prototype atmospheric-pressure plasma jet (APPJ)-processed reduced graphene oxide (rGO)-modified carbon electrochemical sensors integrated with 3D-printed microfluidic channels. Dopamine (DA) solutions with various concentrations are used for the model test. The APPJ-calcined rGO coating significantly enhances the electrochemical signal for DA detection by 18 times. X-ray photoelectron spectroscopy (XPS) shows that APPJ-calcined rGO-modified carbon electrodes have more oxygen-containing surface functional groups, leading to the enhanced electrochemical reactivity. The cyclic voltammetry (CV) curves of solutions with various DA concentrations are well-distinguishable in the presence of uric acid (UA) and ascorbic acid (AA) as interfering agents. (C) 2017 The Electrochemical Society. All rights reserved.