Incorporating ZnFe2O4 nanoparticles and β-cyclodextrin into carbon paste electrode as a sensitive methyldopa electrochemical sensor

A new electrochemical sensor for antihypertensive drug methyldopa (MDOP) was prepared from a carbon paste electrode modified by ZnFe2O4 nanoparticles synthesized hydrothermally and β-cyclodextrin as a supermolecule. ZnFe2O4 nanoparticles were examined using scanning electron microscopy and infrared spectroscopy. Comparison of unmodified electrode with electrodes modified by ZnFe2O4 and β- cyclodextrin and their nanocomposite showed that MDOP had a higher oxidation current on the surface of the modified electrode by composite than other electrodes at pH = 7. Also, the oxidation potential is lower than other electrodes at this pH. The modified electrode can measure MDOP in the concentration range of 1-100 μM with a detection limit of 0.3 μM. The good features of this sensor are its repeatability and good selectivity. This sensor is also able to measure MDOP in the blood serum sample.