Preparation of novel magnetic and fluorescent CS–Fe3O4@CdSeS nanoparticles for simultaneous removal and optical determination of trace copper ions

Novel magnetic and fluorescent CS–Fe3O4@CdSeS nanoparticles (MF-CSNPs) were synthesized by incorporating Fe3O4–chitosan nanoparticles and mercaptopropionic acid capped alloyed CdSeS quantum dots into a chitosan matrix via an electrostatic interaction. The structure and properties of these novel MF-CSNPs were characterized by UV-visible, FL, XRD, ICP-AES, VSM and TEM. MF-CSNPs are found to adsorb copper ions with a high saturation adsorption capacity of 260 mg g−1, above 95.0 wt% of the copper ions can be enriched and removed from aqueous systems in minutes by manipulating the MF-CSNPs with an external magnetic field. The fluorescence signals of the MF-CSNPs could be quenched effectively by the adsorbed copper ions. Linear relationships are established between the relative fluorescence intensity of the MF-CSNPs and the concentration of copper ions. The linear range and limit of detection for copper ions depend on the concentration of MF-CSNPs. The linear range varies in the concentration range of 0.21–80 μg L−1 or 0.40–700 μg L−1, with the lowest limit of detection of 0.022 μg L−1 being calculated after enrichment. Trace copper ions in water can be simultaneously removed and determined using MF-CSNPs.