title: Graphene oxide sheets immobilized polystyrene for column preconcentration and sensitive determination of lead by flame atomic absorption spectrometry.
abstract: A novel solid-phase extractant was synthesized by coupling graphene oxide (GO) on chloromethylated polystyrene through an ethylenediamine spacer unit to develop a column method for the preconcentration/separation of lead prior to its determination by flame atomic absorption spectrometry. It was characterized by Fourier transform infrared spectroscopy, far-infrared spectroscopy, thermogravimetric analysis/differential thermal analysis, scanning electron microscopy, energy-dispersive spectrometry, and transmission electron microscopy. The abundant oxygen-containing surface functional groups form a strong complex with lead, resulting in higher sorption capacity (227.92 mg g(-1)) than other nanosorbents used for sorption studies of the column method. Using the column procedure here is an alternative to the direct use of GO, which restricts irreversible aggregation of GO and its escape into the ecosystem, making it an environmentally sustainable method. The column method was optimized by varying experimental variables such as pH, flow rate for sorption/desorption, and elution condition and was observed to exhibit a high preconcentration factor (400) with a low preconcentration limit (2.5 ppb) and a high degree of tolerance for matrix ions. The accuracy of the proposed method was verified by determining the Pb content in the standard reference materials and by recovery experiments. The method showed good precision with a relative standard deviation <5%. The proposed method was successfully applied for the determination of lead in tap water, electroplating wastewater, river water, and food samples after preconcentration.
authors.affiliation: Analytical Research Laboratory, Department of Chemistry, Aligarh Muslim University , Aligarh, India 202 002.
authors.forename: Aminul
authors.initials: A
authors.lastname: Islam
authors.forename: Hilal
authors.initials: H
authors.lastname: Ahmad
authors.forename: Noushi
authors.initials: N
authors.lastname: Zaidi
authors.forename: Suneel
authors.initials: S
authors.lastname: Kumar
mesh_terms: D004777:Environment; D006108:Graphite / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007477:Ions; D007854:Lead / Q000302:isolation & purification*; D008855:Microscopy, Electron, Scanning; D008863:Microspheres; D010087:Oxides / Q000737:chemistry*; D011137:Polystyrenes / Q000737:chemistry*; D059027:Recycling; D015203:Reproducibility of Results; D012212:Rheology; D052616:Solid Phase Extraction; D012996:Solutions; D013054:Spectrophotometry, Atomic / Q000379:methods*; D013696:Temperature; D013997:Time Factors
chemical_list: D007477:Ions; D010087:Oxides; D011137:Polystyrenes; D012996:Solutions; D007854:Lead; D006108:Graphite