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Flame Atomic Absorption Spectrometry (flame + atomic_absorption_spectrometry)
Selected AbstractsPreconcentration and Determination of Copper(II) Using Octadecyl Silica Membrane Disks Modified by 1,5-Diphenylcarhazide and Flame Atomic Absorption SpectrometryCHINESE JOURNAL OF CHEMISTRY, Issue 11 2007Ali MOGHIMI Abstract A simple and reproducible method for the rapid extraction and determination of trace amounts of copper(II) ions using octadecyl-bonded silica membrane disks modified by 1,5-diphenylcarbazide (DPC) and atomic absorption spectrometry was presented, which was based on complex formation on the surface of the ENVI-18 DISKTM disks followed by stripping of the retained species by minimum amounts of appropriate organic solvents. The elution was efficient and quantitative. The effect of potential interfering ions, pH, ligand amount, stripping solvent, and sample flow rate were also investigated. Under the optimal experimental conditions, the break-through volume was found to be about 1000 mL providing a preconcentration factor of 400. The maximum capacity of the disks was found to be (255±5) µg for Cu2+, and the limit of detection of the proposed method was 5 ng per 1000 mL. The method was applied to the extraction and recovery of copper in different water samples. [source] Preparation and Certification of High-Grade Gold Ore Reference Materials (GAu 19-22)GEOSTANDARDS & GEOANALYTICAL RESEARCH, Issue 1 2001Tiexin Gu materiau de référence certifié; gisement d 'or,GAu 19-22,IGGE,valeurs certifiées Two types of gold deposit with both good homogeneity and a high-grade of gold were selected to prepare four gold ore reference materials (GAu-19,GAu-20,GAu-21 and GAu-22) by the Institute of Geophysical and Geochemical Exploration (IGGE),China. Seven laboratories participated in the certification programme. Volumetric methods for GAu19-21 and atomic absorption spectrometry for GAu-22 were used for the homogeneity testing,the coefficient of variation being found to be less than 3%. After sample digestion and preconcentration,the samples were analysed by flame atomic absorption spectrometry (AAS),colorimetry,neutron activation analysis (NAA)and volumetric analysis. The certified values for the gold concentration in GAu19-22 are 18.3 ,g g -1, 32.3 ,g g -1, 53.0 ,g g -1 and 5.72 ,g g -1,respectively. Deux types de gisements d'or, présentant à la foisune bonne homogénéité et une teneur élevée en or, ont été sélectionnés par l'Institut d 'Exploration Géophysique et Géochimique de Chine (IGGE)afin de préparer quatre matériaux de référence pour l'or (GAu-19,GAu-20,GAu-21 et Gau-22). Sept laboratoires ont participé au programme de certification. Des méthodes volumétriques (GAu-19-21)et de spectrométrie par absorption atomique (GAu 22)ont été utilisées pour tester l'homogénéité de ces échantillons;les coefficients de variation se sont révélés inférieurs à 3%.Après la mise en solution et la préconcentration des échantillons,ceux-ci ont eté analysés par spectrométrie d 'absorption atomique (AAS), colorimétrie,activation neutronique (NAA)et analyse volumétrique.Les valeurs certifiées pour la concentration en or de GAu19-22 sont respectivement de 18.3 ,g.g -1,32.3 ,g g -1, 53.0 ,g g -1 et 5.72 ,g g -1. [source] Functionalized HMS mesoporous silica as solid phase extractant for Pb(II) prior to its determination by flame atomic absorption spectrometryJOURNAL OF SEPARATION SCIENCE, JSS, Issue 10 2007Damián Pérez-Quintanilla Abstract In this work, a mesoporous silica has been chemically modified with 5-mercapto-1-methyl-1-H-tetrazol using the homogeneous route (MTTZ-HMS). This synthetic route involved the reaction of 5-mercapto-1-methyl-1-H-tetrazol with 3-chloropropyltriethoxysilane, prior to immobilization on the support. The resulting material has been characterized and employed as solid phase extractant for Pb(II). The effect of several variables (stirring time, pH, temperature, metal concentration, presence of other metals) has been studied using batch and column techniques. In batch experiments, 15 min stirring time, 55°C and pH 8 were the optimal conditions for Pb(II) adsorption. In column experiments, sorption was quantitative for 1000 mL of 2.41×10,4 mM of Pb(II) solution and adsorbed ions were eluted out by 5 mL of 1 M HCl (preconcentration factor of 200). Spiked tap water was used for the preconcentration and determination of Pb(II) by flame atomic absorption spectrometry, and a 100% recovery was obtained. The LOD and LOQ values of the proposed method were found to be 3.52×10,3 and 4.20×10,3 mM, respectively. The RSD for three preconcentration experiments was found to be ,2%. The linear working range for measurements was between 2×10,3 and 0.14 mM (y = 0.0136x + 0.0007, R2 = 0.9999). [source] Determination of lead content in medicinal plants by pre-concentration flow injection analysis,flame atomic absorption spectrometryPHYTOCHEMICAL ANALYSIS, Issue 6 2009Marina M. A. Campos Abstract Introduction , Although medicinal plants are widely used throughout the world, few studies have been carried out concerning the levels of heavy metal contaminants present. Such metals are highly toxic to living organisms even in low concentrations owing to their cumulative effect. The present paper describes the the development of a pre-concentration flow injection analysis-flame atomic absorption spectrometric system to determine the lead content in medicinal plants at the ppb level. Objective , To develop a pre-concentration flow injection analysis-flame atomic absorption spectrometric system to determine the lead content in medicinal plants at the ppb level. Methodology , A pre-concentration flow system was coupled to a flame atomic absorption spectrometer. The plant samples were analysed after nitroperchloric digestion. The proposed system was optimised by evaluating the following parameters: nature, concentration and volume of the eluent solution, elution flow rate, elution efficiency, pre-concentration flow rate and pre-concentration time. Results , The proposed system exhibited good performance with high precision and repeatability (RSD , 2.36%), excellent linearity (r = 0.9999), low sample consumption (10.5 mL per determination) and an analytical throughput of 55 samples/h. Lead concentrations ranged from 3.37 ± 0.25 to 7.03 ± 0.51 ,g/g in dry material. This concentration interval is greater than that previously published in the literature. Conclusion , The inclusion of a pre-concentration column in the flow manifold improved the sensitivity of the spectrometer. Thus, it was possible to determine the analyte at the ng/mL level in sample solutions of medicinal plants. This is a very important accomplishment, especially when the cumulative effect of heavy metals in living organisms is considered. Copyright © 2009 John Wiley & Sons, Ltd. [source] Determination of nickel, calcium and magnesium in xylem sap by flame atomic absorption spectrometry using a microsampling techniquePHYTOCHEMICAL ANALYSIS, Issue 5 2009Sheila Alves Abstract Introduction Knowledge of xylem sap chemical composition is important to the understanding of translocation, detoxification and tolerance mechanisms. However, the small amount of sample available often hampers its characterisation. Hence, low volume consumption techniques are needed for xylem sap analysis. Objective To develop a microsampling technique for the determination of elements in xylem sap from different plants by flame atomic absorption spectrometry (FAAS). Methodology The microsampling device was optimised in terms of sample volume and integration time. The analytical characteristics of the microsampling technique (µ -FAAS) were established and compared with those of FAAS with traditional continuous nebulisation. The method was validated by means of an independent technique. Results Ca, Mg and Ni were determined in a 50 µL aliquot of xylem sap solution/element that was introduced directly into the flame via the microsampling accessory. Good precision was obtained with relative standard deviations of 1.1, 0.6 and 2.3% for Ca, Mg and Ni, respectively. Matrix effects resulting from the physical characteristics of the samples and possible chemical interferences caused by phosphate and/or sulphate were ruled out. Conclusion A simple, rapid and reproducible microsampling technique coupled to FAAS was developed and successfully applied in the determination of Ca, Mg and Ni in xylem sap. Copyright © 2009 John Wiley & Sons, Ltd. [source] Evaluation of zinc level in skin of patients with necrolytic acral erythemaBRITISH JOURNAL OF DERMATOLOGY, Issue 3 2010H.A.M. Moneib Summary Background, Necrolytic acral erythema (NAE) is considered a cutaneous sign of hepatitis C virus infection. Its exact pathogenesis is still not fully understood, with some reports about decreased serum zinc levels but none about its level in the skin. Objectives, To assess skin (lesional and perilesional) and serum zinc levels in patients with NAE and compare them with levels in control subjects. Methods, Fifteen patients with NAE and 10 healthy controls were included in this study. Assessment of zinc level, in serum by graphite furnace atomic absorption spectrophotometry and in lesional and perilesional skin biopsies by flame atomic absorption spectrometry, was done in all subjects. Re-evaluation of serum and lesional skin zinc level was done after oral zinc treatment. Results, Mean ± SD zinc levels were significantly lower in patients (serum 0·44 ± 0·13 mg L,1; lesional skin 42·6 ± 18·9 mg L,1; perilesional skin 32·5 ± 17·2 mg L,1) than controls (serum 1·17 ± 0·29 mg L,1; skin 100·1 ± 2·77 mg L,1), with a positive correlation between lesional and perilesional skin zinc (r = 0·91, P < 0·01). Oral zinc supplementation significantly increased serum and skin zinc levels (by 159% and 4%, respectively; P < 0·05). Conclusions, NAE is associated with decreased serum and skin zinc levels. Oral zinc supplementation corrects decreased levels of plasma and skin zinc much earlier than the desired clinical benefits appear. [source] Study on Preconcentration of Trace Copper Using Microcrystalline Triphenylmethane Loaded with Malachite GreenCHINESE JOURNAL OF CHEMISTRY, Issue 4 2007Yong Liang Abstract The paper describes a novel method for copper preconcentration using microcrystalline triphenylmethane loaded with malachite green prior to the determination by the flame atomic absorption spectrometry (FAAS). Under the optimum conditions, Cu(II) can be totally adsorbed on the surface of microcrystalline triphenylmethane, and completely separated from Pb(II), Cd(II), Co(II), Cr(III), Ni(II), Mn(II), Fe(III) and Al(III) by controlling acidity. The preconcentration factor of this proposed method is 200. The recovery is in a range of 97.5%,105%. The relative standard deviation (RSD) is not beyond 3.0%. The proposed method has been successfully applied to the determination of trace copper in various water samples with satisfactory results. [source] | ||||||||||