Electrochemical detection of serotonin based on a poly(bromocresol green) film and Fe3O4 nanoparticles in a chitosan matrix

A composite film containing poly(bromocresol green), magnetic nanoparticles and multiwalled carbon nanotubes was fabricated for the sensitive determination of serotonin. The poly(bromocresol green) was prepared by electropolymerization on a glassy carbon electrode surface, then the multiwalled carbon nanotubes and magnetic nanoparticles in a chitosan matrix were dropped onto the surface of the poly(bromocresol green) film. The modified electrode displayed an enhanced differential pulse voltammetric response to serotonin in the presence of dopamine. Its peak current (at an oxidation voltage of 0.36 V vs. Ag/AgCl) increased linearly in the serotonin concentration range 0.5-100 mu M with a detection limit of 80 nM (at an S/N of 3). The sensor was highly sensitive and stable. It was applied to the direct determination of serotonin spiked into human serum samples. These results show that the nanocomposite films are good modifying materials for use in the fabrication of electrochemical sensors.