VOLTAMMETRIC ANALYSIS OF MELATONIN AND DOPAMINE BY USING GRAPHENE OXIDE/POLYIMIDE BASED BIOSENSOR

Abstract

In this research, for the simultaneous analysis of melatonin (MET) and dopamine (DP), graphene oxide/polyimide (GO/PI) composite electrode was prepared with the modification of Pt electrode. Firstly, GO/PI composite structure was synthesized from 2,6-diaminopyridine based polyimide and 5% GO. Then, the obtained composite structure as the membrane was coated on the electrode surface. MET and DP responses of the prepared GO/PI composite electrode were investigated by Differential Pulse Voltammetry (DPV) technique. Linearity was obtained over a concentration range of 85-105 µM for MET (R2 = 0.9976). For DP analysis, the linearity was also monitored over a concentration range of 85-105 µM (R2=0.9988). The detection limits of GO/PI modified electrode were approximately 13.45×10−5 M and 9.61×10−5 M for MET and DP, respectively. The prepared GO/PI composite modified electrode exhibited good repeatability, wide linear range and sensitivity for MET and DP. The obtained results indicated that while uric acid (UA) is present in the medium, GO/PI composite can be used as an excellent membrane in the design of voltammetric sensors to analyze MET and DP simultaneously.