Sadegh Karimi

Herein, we present a facile and convenient method for detection and determination of some of parabens using Fe3O4@SiO2-AgNPs nanocomposite. Silver nanoparticles (AgNPs) were synthesized using Algae extract and stabilized with Fe3O4@SiO2 core-shell NPs. The fabricated nanocomposite were characterized using UV−Vis spectroscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, and dynamic light scattering. Fe3O4@SiO2-AgNPs was evaluated as nanocatalysts in the oxidative degradation of methyl, butyl and benzyl paraben with hydrogen peroxide (H2O2). The catalytic degradation of targets was completed within 10 min, demonstrating excellent catalytic properties for fabricated nano-catalyst. The concentration was linear over the range of 3-40, 4- 100 and 8-100 ϻM for methyl paraben, butyl paraben and benzyl paraben, respectively. Melatonin is a natural hormone and with the advancement of age its production declines and thereby may result in some neurological disorders. However, due to the low concentration, the analysis of Melatonin is a challenging task. The aim of the work described in this paper was to provide a fast, easy, inexpensive, precise, and accurate method for the colorimetric determination, which exhibits excellent linearity in aqueous solutions (r2 = 0.996) for analyte concentrations of 0.08-100 M at pH 4. The detection limit was found 0.058μM. The proposed method was successfully applied to analyze the actual samples with satisfactory assay results.