It is known that dopamine DA ascorbic acid AA and
It is known that dopamine (DA), ascorbic Cy5 hydrazide (AA) and uric acid (UA) always coexist with glucose in human blood  and . The interferences study was conducted by determination of glucose in the presence of 0.5 mM of DA, AA and UA based on amperometric technique. The glucose signal was not significantly changed when 0.5 mM of these substances were added to the electrolyte solution (See Supporting Information, Fig. S5).
Reproducibility of the GCE-GNs-NBpoly-GOx electrode is investigated by recording the response of four identically made enzyme electrodes in 0.1 M PBS containing 0.4 mM glucose. The small relative standard deviation (RSD) of 4.6% indicates high reproducibility of the method for preparation of GCE-GNs-NBpoly-GOx electrode. The repeatability of the sensor is also verified. A set of four consecutive measurements is performed for one of the GCE-GNs-NBpoly-GOx electrodes in 0.1 M PBS containing 0.4 mM glucose. The obtained results with RSD of 3.6%, demonstrates excellent repeatability.