Electrochemical biosensor for simultaneous determination of dopamine and serotonin based on electrochemically reduced GO-porphyrin

Covalently bonded GO-P was prepared by the condensation reaction of graphene oxide (GO) and 5,15-pentafluorophenyl-10,20-p-aminophenylporphyrin (P). The prepared GO-P was characterized by FT-IR, UV–vis spectroscopy, XPS and FE-SEM. Electrochemically reduced GO-P (ERGO-P) was obtained by electrochemical reduction of GO-P in PBS solution of pH 5. The ERGO-P was employed to detect neurotransmitters such as dopamine (DA) and serotonin (5-HT). The effects of GO-P amount, pH (4.04–9.01) of PBS solution were investigated for the detection of DA and 5-HT. The detection limits of DA and 5-HT were 3.5 × 10−2 μM and 4.9 × 10−3 μM, respectively. Ascorbic acid (AA) as an interference material gives negligible effect on the DA and 5-HT responses, demonstrating the high selectivity of the proposed biosensor.