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 hydrothermally synthesized ZnFe2O4 nanoparticles and β-cyclodextrin as a supermolecule. ZnFe2O4 nanoparticles were charectrized using scanning electron microscopy (SEM) 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 at the modified electrode by composite than each other electrodes at pH = 7. Moreover, 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 proposed sensor shows good repeatability and selectivity. It is also able to measure MDop in the blood serum sample.