Mesoporous Titanium Dioxide as a Novel Solid-Phase Extraction Material for Flow Injection Micro-Column Preconcentration On-Line Coupled with ICP-OES Determination of Trace Metals in Environmental Samples
Mesoporous titanium dioxide as a novel solid-phase extraction material for flow injection micro-column preconcentration on-line coupled with ICP-OES determination of trace metals (Co, Cd, Cr, Cu, Mn, Ni, V, Ce, Dy, Eu, La and Yb) in environmental samples was described. Possessing a high adsorption capacity towards the metal ions, mesoporous titanium dioxide has found to be of great potential as an adsorbent for the preconcentration of trace metal ions in samples with complicated matrix. The experimental parameters including pH, sample flow rate, volume, elution and interfering ions on the recovery of the target analytes were investigated, and the optimal experimental conditions were established. Under the optimized operating conditions, a preconcentration time of 90s and elution time of 18s with enrichment factor of 10 and sampling frequency of 20h(-1) were obtained. The detection limits of this method for the target elements were between 0.03 and 0.36mugL(-1), and the relative standard deviations (R.S.D.s) were found to be less than 6.0% (n=7, c=5ngmL(-1)). The proposed method was validated using a certified reference material, and has been successfully applied for the determination of the afore mentioned trace metals in natural water samples and coal fly ash with satisfactory results.
[Show abstract][Hide abstract] ABSTRACT: Graphene is a new carbon-based material that is of interest in separation science. Graphene has extraordinary properties including nano-sized, high surface area, thermally and chemically stable, and provide excellent adsorption affinity to pollutants. Its adsorption mechanisms are through non-covalent interactions (π-π stacking, electrostatic interactions and H-bonding) for organic compounds and covalent interactions for metal ions. These properties lead to graphene-based material becoming a desirable adsorbent in a popular sample preparation technique known as solid phase extraction (SPE). Numerous publications on graphene applications are available in recent times, but few review papers focused on its applications in analytical chemistry. This article focuses on recent pre-concentration of trace elements, organic compounds and biological species using SPE-based graphene, graphene oxide and their modified forms. Solid phase microextraction and micro SPE methods based on graphene are discussed.
") low consumption of organic solvent (7) time saving and (8) cost saving (Camel 2003), solid phase extraction (SPE) (Jibrin et al. 2007; Huang et al. 2007), technique has become increasingly popular for the enrichment of metal ions prior to their determination. This study, describes a procedure based on selective enrichment by solid phase extraction of cadmium in nail sample followed by preconcentration on the surface of the carbon paste electrode (double preconcentration) and employing of the very sensitive differential pulse voltammetry technique to achieve very low limit of detection required for the determination of cadmium in human samples. "
[Show abstract][Hide abstract] ABSTRACT: Cadion was coated on carbon powder and used as a solid phase for selective extraction and preconcentration of cadmium ions. Complexed cadmium ions were eluted from solid phase by 5 mL, nitric acid (2.0 M) with the flow rate of 2 mL min(-1).The resulted solution was used for accumulation of the cadmium metal at the surface of the carbon paste electrode at -1.3 V reduction potential. Finally, cadmium was reoxidized and the differential pulse voltammogram recorded at the potential range of -0.55 to -0.2 V. Calibration graph was plotted in the concentration range of 0.5-50 μg L(-1) of cadmium. Detection limit 0.06 μg L(-1) was calculated based on the 3 Sb/m. The RSD was 9.13 % (n = 4) for cadmium concentration of 10 μg L(-1) with preconcentration factor of 100. Method was successfully used for the determination of cadmium in finger nail samples and after spiking the samples, the recoveries were evaluated >96 %.
Bulletin of Environmental Contamination and Toxicology 02/2015; 94(4). DOI:10.1007/s00128-015-1484-x · 1.26 Impact Factor
"Another advantage is that solid phase can be repeatedly used. Several adsorbents have been proposed for heavy metal extraction, e.g., cellulose , activated carbon , Nymphaea rubra , amberlite XAD-7 resin , synthetic zeolites  , modified chromosorb , silica gel , mesoporous silica , and activated alumina . Among all these adsorbents, alumina plays an important role in SPE studies of heavy metals . "
[Show abstract][Hide abstract] ABSTRACT: Nano-alumina modified by 9-aminoacridine was used as a sorbent for separation and determination of dichromate ions from water. Statistical method, based on surface response design, has been used for the optimization of dichromate ions elution from 9-aminoacridine nano-alumina. The adsorbed dichromate ions were found to be eluted quantitatively with 0.8 mol L À1 KCl in 1.6 mol L À1 NaOH which optimized by response surface design. Under optimum conditions, the accuracy, precision (relative standard deviation, RSD%) and R-square of the method were calculated as >98, <3, and >94%, respectively. Remarkable agreement between experimental and theoretical data was confirmed the predicted assumption. The method was applied to the simultaneous determination of dichromate in natural and industrial water samples. We also examined the retention of dichromate anions in the presence of Cl À , NO À 3 , and SO 2À 4 anions at pH 3.
CLEAN - Soil Air Water 03/2012; 40(3):272-277. DOI:10.1002/clen.201000224 · 1.95 Impact Factor
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