title: Graphene-silica hybrid in efficient preconcentration of heavy metal ions via novel single-step method of moderate centrifugation-assisted dispersive micro solid phase extraction.
abstract: Novel nanoadsorbent of graphene-silica hybrid was synthesized via chemical vapor deposition (CVD) method. Graphene sheets were catalytically grown on a silica-based substrate and after being characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM), their high efficacy in adsorption of metal ions (lead, cadmium, and chromium) was examined. It was found that the presence of silica within the G-SiO2 structure imparts an amphiphilic property to the hybrid that enables it to interact with both free and bounded metal ions present in the biological samples. Utilization of the innovative method of moderate centrifugation-assisted dispersive micro solid phase extraction (MCDµSPE) coupled with electrothermal atomic absorption spectrometry (ETAAS), not only facilitated absolute separation of the fabricated nanoadsorbent from the solvent, but also helped complete recovering of the scant volume of desorbed supernatant. Thus, microliter amount of desorption solvent can be regained completely by MCDµSPE method without sorbent loss. Various parameters affecting the extraction efficiency were investigated and admirable linearity from 0.012 to 12.5 µg L(-1) and favorable detection limits (LOD) could be recorded. Intra day precision (RSD, n=10) ranged from 3.1 to 3.8%, whereas inter day precision (RSD, n=5) ranged from 6.3 to 7.2%.
authors.affiliation: Department of Chemistry, College of Science, Semnan University, P.O. Box 35131-19111, Semnan, Iran.
authors.forename: Mehri
authors.initials: M
authors.lastname: Ghazaghi
authors.affiliation: Department of Chemistry, College of Science, Semnan University, P.O. Box 35131-19111, Semnan, Iran. Electronic address: hzmousavi@semnan.ac.ir.
authors.forename: Hassan Zavvar
authors.initials: HZ
authors.lastname: Mousavi
authors.affiliation: Nanotechnology Research Center, Research Institute of Petroleum Industry (RIPI), West Entrance Blvd., Olympic Village, P.O. Box 14857-33111, Tehran, Iran.
authors.forename: Ali Morad
authors.initials: AM
authors.lastname: Rashidi
authors.affiliation: Occupational and Environmental Health Research Center (OEHRC), Iranian Petroleum Industry Health Research Institute (IPIHRI), Tehran, Iran.
authors.forename: Hamid
authors.initials: H
authors.lastname: Shirkhanloo
authors.affiliation: Nanotechnology Research Center, Research Institute of Petroleum Industry (RIPI), West Entrance Blvd., Olympic Village, P.O. Box 14857-33111, Tehran, Iran.
authors.forename: Reza
authors.initials: R
authors.lastname: Rahighi
keywords: Cadmium; Centrifugation-assisted dispersive micro solid phase extraction; Chromium; Graphene-silica hybrid; Lead; Nanoadsorbent