Fluorescein isothiocyanate conjugated graphene oxide for detection of dopamine

Dopamine plays a crucial and essential role in the function of human metabolism. It is important to develop selective and sensitive materials for the detection of dopamine (DA) without the interference by coexisting compounds. In this study, fluorescein isothiocyanate (FITC) conjugated graphene oxide (GO) microsheets were developed and this system was used as a novel supporting matrix for adsorption based selective and sensitive detection of dopamine. Fluorescein isothiocyanate conjugated graphene oxide microsheets (FITC–GOs) showed high affinity to DA. Selectivity of FITC–GOs to DA is 31 and 28 times higher than that of coexisting molecules, ascorbic acid (AA) and uric acid (UA), respectively. Compared with DA, affinity of FITC–GOs to AA and UA is non-specific and can be negligible. Low detection limit of 2 × 10−7 M (0.2 μM) for DA was obtained. All experiments were carried out in the neutral solutions at around physiological pH. This study provides a simple and easy method for selective and sensitive detection of dopamine in the mixture of other most abundant coexisting molecules that generally cause interference.