title: Nanometer-sized ceria-coated silica-iron oxide for the reagentless microextraction/preconcentration of heavy metals in environmental and biological samples followed by slurry introduction to ICP-OES.
abstract: A slurry suspension sampling technique is developed and optimized for the rapid microextraction of heavy metals and analysis using nanometer-sized ceria-coated silica-iron oxide particles and inductively coupled plasma optical emission spectrometry (ICP-OES). Magnetic-silica material is synthesized by a co-precipitation and sol-gel method followed by ceria coating through a precipitation. The large particles are removed using a sedimentation-fractionation procedure and a magnetic homogeneous colloidal suspension of ceria-modified iron oxide-silica is produced for microextraction. The nanometer-sized particles are separated from the sample solution magnetically and analyzed with ICP-OES using a slurry suspension sampling approach. The ceria-modified iron oxide-silica does not contain any organic matter and this probably justifies the absence of matrix effect on plasma atomization capacity, when increased concentrations of slurries are aspirated. The As, Be, Mo, Cr, Cu, Pb, Hg, Sb, Se and V can be preconcentrated by the proposed method at pH 6.0 while Mn, Cd, Co and Ni require a pH ≥ 8.0. Satisfactory values are obtained for the relative standard deviations (2-6%), recoveries (88-102%), enrichment factors (14-19) and regression correlation coefficients as well as detectability, at sub-μg L(-1) levels. The applicability of magnetic ceria for the microextraction of metal ions in combination with the slurry introduction technique using ICP is substantiated by the analysis of environmental water and urine samples.
authors.affiliation: Cp Foodlab, P.O. Box 28729, 2082 Nicosia, Cyprus.
authors.forename: A
authors.initials: A
authors.lastname: Dados
authors.affiliation: Cp Foodlab, P.O. Box 28729, 2082 Nicosia, Cyprus; Department of Chemistry, University of Ioannina, Ioannina 451 10, Greece.
authors.forename: E
authors.initials: E
authors.lastname: Paparizou
authors.affiliation: Department of Mechanical Engineering, Materials Science and Engineering, Cyprus University of Technology, 3036 Limassol, Cyprus.
authors.forename: P
authors.initials: P
authors.lastname: Eleftheriou
authors.affiliation: Cp Foodlab, P.O. Box 28729, 2082 Nicosia, Cyprus.
authors.forename: C
authors.initials: C
authors.lastname: Papastephanou
authors.affiliation: Department of Chemistry, University of Ioannina, Ioannina 451 10, Greece. Electronic address: cstalika@cc.uoi.gr.
authors.forename: C D
authors.initials: CD
authors.lastname: Stalikas
mesh_terms: D002138:Calibration; D002563:Cerium / Q000737:chemistry*; D007700:Kinetics; D053768:Metal Nanoparticles / Q000737:chemistry*; D019216:Metals, Heavy / Q000302:isolation & purification*; D017550:Spectroscopy, Fourier Transform Infrared; D013057:Spectrum Analysis / Q000379:methods*; D014961:X-Ray Diffraction
chemical_list: D019216:Metals, Heavy; D002563:Cerium
keywords: Heavy metals microextraction/preconcentration; Inductively coupled plasma-optical emission spectrometry; Nanometer-sized magnetic ceria; Slurry suspension sampling