Simultaneous voltammetric determination for DA, AA and NO2− based on graphene/poly-cyclodextrin/MWCNTs nanocomposite platform

In the present work, graphene sheets (GS) and multiwall carbon nanotubes (MWCNTs) were dispersed in the mixed solution of cyclodextrin (CD) and cyclodextrin prepolymer (pre-CD) and were used as modifier to fabricate chemical modified electrode to simultaneous detect dopamine (DA), ascorbic acid (AA) and nitrite (NO2−). CD cross-linked pre-CD (CDP) displays excellent film forming ability, which made the electrode stable. Comparing with CDP–GS, CDP–MWCNTs and CDP–GS–MWCNTs modified electrodes, the CDP–GS–MWCNTs displays higher catalytic activity and selectivity toward the oxidation of DA, AA and NO2−, revealing that MWCNTs effectively inhibited the stacking of individual GS and enhanced the utilization of GS based composites. The host–guest chemical reaction ability of CD and π–π stacking interaction between detected molecules and GS–MWCNTs surface were considered as the main reasons of the successfully simultaneous detection of DA, AA and NO2−. Cyclic voltammetry (CV), scanning electron microscopy (SEM) and different pulse voltammetry (DPV) were employed to characterize the biosensor. The linear response range for AA, DA and NO2− were 5 μM–0.48 mM, 0.15–21.65 μM and 5 μM–6.75 mM, respectively and the detection limits were 1.65 μM, 0.05 μM and 1.65 μM.