Luminescent and magnetic Fe3O4/Py/PAM nanocomposites for the chromium(VI) determination

A novel luminescent and magnetic Fe3O4/pyrene/polyacrylamide (Fe3O4/Py/PAM) nanocomposite has been prepared under ultrasonic radiation. This magnetic nanocomposite combined with pyrene would lead to a special functional magnetic luminescent composite that enjoys both the advantages of magnetic nanoparticles of Fe3O4 and fluorescence nanoparticles of pyrene. Taking advantage of the magnetic property of Fe3O4 nanocomposites, we can separate Fe3O4/Py/PAM nanocomposites from solution easily just by using a permanent magnet. Based on the fluorescence quenching of Fe3O4/Py/PAM nanocomposites by Cr(VI), a method for the selective determination of Cr(VI), without separation of Cr(III) in water, was developed. Under optimal experimental conditions, a limit of detection of 0.01 μg mL−1 was achieved. The calibration curve was linear over the concentration range of 0.1-14.0 μg mL−1 with a correlation coefficient of 0.9975. The proposed method has been applied to the selective quantification of Cr(VI) in synthetic samples and wastewater samples with the satisfactory results.