We introduce a new method to determine methyldopa without the interference of phenylephrine and guaifenesin. For this purpose, a carbon paste electrode was modified with graphene and ethyl 2‐(4‐ferrocenyl[1,2,3]triazol‐1‐yl)acetate. According to electrochemical studies, oxidation current of methyldopa on the surface of the modified electrode increased and shifted towards negative potentials. This modified electrode demonstrated two linear ranges of 0.4–30.0 μM and 30.0–500.0 μM with a detection limit of 0.08 μM. No change was observed in the sensitivity of the modified electrode towards methyldopa in the presence of phenylephrine and guaifenesin, which enables the simultaneous or independent measurement of the three moieties. The efficiency of the proposed modified electrode was evaluated through the determination of these substances in real samples.
