Because dopamine (DA) is one of the most critical neurotransmitters that influence a wide variety of motivated human behaviors, it is necessary to develop a facile diagnostic tool that can quantify the physiological level. In this study, core–shell magnetic silica nanoparticles (Fe3O4@SiO2) were prepared using a modified sol–gel reaction. The Fe3O4@SiO2 were functionalized using 3-aminophenylboronic acid (APBA) via a facile and rapid synthetic route, hereafter referred to as Fe3O4@SiO2@APBA The resultant Fe3O4@SiO2@APBA not only adsorbed DA molecules, but also were easily separated from solution using a simple magnetic manipulation. The adsorbed amounts of DA by the Fe3O4@SiO2@APBA were quantified by measuring the changes in fluorescence intensity of polydopamine (at 463 nm) originated from the self-polymerized DA remained in the supernatant before and after the adsorption process. The Fe3O4@SiO2@APBA exhibited two-stage adsorption behavior for DA, and the maximal adsorption capacity was 108.46 μg/g at pH 8.5. Our particle system demonstrated the potential application for extracting compounds with cis-diols (including catechol amines) from the biological fluid.
