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Absorption Spectrometry (absorption + spectrometry)
Kinds of Absorption Spectrometry Selected AbstractsAccumulation of toxic metals (Pb and Cd) in the sea urchin Diadema aff. antillarum Philippi, 1845, in an oceanic island (Tenerife, Canary Islands)ENVIRONMENTAL TOXICOLOGY, Issue 3 2010Ofelia Dolores Hernández Abstract This document shows the results obtained from a study on the concentration of toxic heavy metals in the internal tissue and exoskeleton of sea urchins, collected from their natural habitat. The levels of lead and cadmium were measured by Graphite Furnace Atomic Absorption Spectrometry. The mean concentrations of lead and cadmium in the internal tissue were 304.04 and 260.54 ,g/kg respectively, whereas in the shell they were 185.02 and 142.48 ,g/kg. We also performed a statistical analysis of the differences in the distribution of metals between their exoskeleton and their internal content, a correlation study of the metal content in internal tissue and shell and sampling areas, and a correlation study between the metal content and sample size. Since the sea urchin Diadema antillarum presents a wide range of variation in metal content, this study suggests that this species is an excellent bioindicator of heavy metal contamination. © 2009 Wiley Periodicals, Inc. Environ Toxicol, 2010. [source] Preconcentration 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] Experimental analysis of Mn segregation in Bridgman-grown gallium antimonide: Dependency on the ampoule radiusCRYSTAL RESEARCH AND TECHNOLOGY, Issue 5 2004J. L. Plaza Abstract This work considered the segregation of manganese in vertical Bridgman-grown GaSb crystals for different ampoule diameters. Experimental data of the impurity distribution were obtained from atomic absorption spectrometry and also Hall measurements. It was demonstrated that the radial segregation is more pronounced in the case of thick ampoule diameters. Furthermore the manganese effective segregation coefficient, resistivity, carrier mobility and density were obtained in each case. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Electrochemical Investigation of Strontium,Metallothionein Interactions , Analysis of Serum and Urine of Patients with OsteoporosisELECTROANALYSIS, Issue 3-5 2009Ivo Fabrik Abstract The main aim of this paper is to study interaction between strontium and metallothionein (MT), and to determine changes in strontium and thiols (MT, reduced glutathione, cysteine, and homocysteine) level in plasma, serum, and urine samples of patients treated with strontium ranelate (SrR). To investigate the interactions between MT and strontium(II) ions, adsorptive transfer stripping technique coupled with differential pulse voltammetry (DPV) the Brdicka reaction was employed. Besides standard Brdicka signals (Co, RS2Co, Cat1, Cat2, Cat3), we observed new signal related to Sr-MT interaction. Further we investigated the effect of various time of interaction, concentration of strontium(II) ions and temperature of supporting electrolyte on Brdicka signals. Optimal time of interaction was 240,s. Under temperature of supporting electrolyte 20,°C, we measured linear dependence of Cat3 signal height on strontium(II) ions concentration. After that we have investigated the possibility of strontium-MT interactions, we were interested in strontium, MT and low molecular mass thiols levels in serum and urine of patients treated with strontium(II) ions to cure osteoporosis. Strontium concentration determined by atomic absorption spectrometry was 55±5,,g/L before and 10,500±1,400,,g/L at the 30th day of SrR administration. Levels of metallothionein in serum ranged from 0.1 to 6.4,,M. Correlation between serum strontium concentration and MT level was determined and correlation coefficient was R=0.93. [source] Multilayer Assemblies Consisting of Tri-Vanadium-Substituted Heteropolyanions and Its Electrocatalytic PropertiesELECTROANALYSIS, Issue 14 2003Shengyong Zhai Abstract We describe the controlled fabrication of ultrathin multilayer films consisting of tri-vanadium- substituted heteropolytungstate anions (denoted as P2W15V3) and a cationic polymer of quaternized poly (4-vinylpyridine) partially complexed with osmium bis(2,2,-bipyridine) (denoted as QPVP-Os) on the 4-aminobenzoic acid (4-ABA) modified glassy carbon electrode (GCE) surface based on layer-by-layer assembly. Cyclic voltammetry and UV-vis absorption spectrometry have been used to easily monitor the thickness and uniformity of thus-formed multilayer films. The V-centered redox reaction of P2W15V3 in the multilayer films can effectively catalyze the reduction of BrO and NO. The resulting P2W15V3/QPVP-Os multilayer film modified electrode behaves as a much promising electrochemical sensor because of the low overpotential for the catalytic reduction of BrO and NO, and the catalytic oxidation of ascorbic acid. [source] Mercury speciation by CE: An updateELECTROPHORESIS, Issue 1 2009Petr Kubán Abstract This review provides an update on mercury speciation by CE. It includes a brief discussion on physicochemical properties, toxicity and transformation pathways of mercury species (i.e. methyl-, ethyl-, phenyl- and inorganic mercury) and outlines recent trends in Hg speciation by CE. CE is presented as a complementary technique to chromatographic separation techniques, especially in cases when speed, high efficiency and low sample volumes are required. The development of suitable sample preconcentration/isolation (sample stacking, ion exchange, liquid,liquid,liquid extraction, dual-cloud point extraction) to achieve low LODs for analysis of trace concentrations of mercury species in real samples is emphasized. Hyphenation of CE to element specific detectors (i.e. electrothermal atomic absorption spectrometry, atomic fluorescence spectrometry, inductively coupled plasma-optical emission spectrometry, inductively coupled plasma-mass spectrometry) is discussed as well as a potential of CE in interaction studies that may provide useful information on interaction of various Hg species with selected bio-macromolecules. [source] Cytogenetic status in newborns and their parents in Madrid: The BioMadrid studyENVIRONMENTAL AND MOLECULAR MUTAGENESIS, Issue 4 2010Virginia Lope Abstract Monitoring cytogenetic damage is frequently used to assess population exposure to environmental mutagens. The cytokinesis-block micronucleus assay is one of the most widely used methods employed in these studies. In the present study we used this assay to assess the baseline frequency of micronuclei in a healthy population of father-pregnant woman-newborn trios drawn from two Madrid areas. We also investigated the association between micronucleus frequency and specific socioeconomic, environmental, and demographic factors collected by questionnaire. Mercury, arsenic, lead, and cadmium blood levels were measured by atomic absorption spectrometry. The association between micronucleated cell frequency and the variables collected by questionnaire, as well as, the risk associated with the presence of elevated levels of metals in blood, was estimated using Poisson models, taking the number of micronucleated cells in 1,000 binucleated cells (MNBCs) as the dependent variable. Separate analyses were conducted for the 110 newborns, 136 pregnant women, and 134 fathers in whom micronuclei could be assessed. The mean number of micronucleated cells per 1,000 binucleated cells was 3.9, 6.5, and 6.1 respectively. Our results show a statistically significant correlation in MNBC frequency between fathers and mothers, and between parents and newborns. Elevated blood mercury levels in fathers were associated with significantly higher MNBC frequency, compared with fathers who had normal mercury levels (RR:1.21; 95%CI:1.02,1.43). This last result suggests the need to implement greater control over populations which, by reason of their occupation or life style, are among those most exposed to this metal. Environ. Mol. Mutagen., 2010. © 2009 Wiley-Liss, Inc. [source] Occurrence of several arsenic compounds in the liver of birds, cetaceans, pinnipeds, and sea turtlesENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 6 2003Reiji Kubota Abstract Concentrations of total arsenic and individual arsenic compounds were determined in livers of birds, cetaceans, pinnipeds, and sea turtles by using hydride generation-atomic absorption spectrometry and high-performance liquid chromatography/inductively coupled plasma-mass spectrometry. Hepatic arsenic concentrations in loggerhead turtles (11.2 ± 3.0 ,g/g dry wt) and black-footed albatrosses (12.2 ± 10.8 ,g/g dry wt) were extremely high among the species examined, and the values were comparable with those of lower trophic marine animals such as fishes, cephalopods, crustaceans, and shellfishes. In all the species, arsenobetaine was the predominant arsenic compound in the livers. Especially, for black-footed albatrosses and black-tailed gull, the mean percentage of arsenobetaine was as high as 97.1 and 87.5, respectively, of extractable arsenic. The present study is among the first on arsenic speciation in avian species. Total arsenic concentration was strongly correlated with the concentration of arsenobetaine, while no significant relationship was observed between total arsenic concentration and other arsenic compounds in these animals. Because arsenobetaine is known to be rapidly excreted into the urine in humans and experimental animals, the observed results suggest that higher trophic marine animals might have a unique metabolism of arsenobetaine and that arsenobetaine plays an important role in the accumulation of arsenic in these animals. [source] A study of the factors controlling the adsorption of Cr(III) on modified montmorillonitesEUROPEAN JOURNAL OF SOIL SCIENCE, Issue 4 2001A. Bakhti Summary We have examined the way that the metallic ion Cr(III) is held by Na-montmorillonite and alumina pillared clay. We used several physico-chemical methods of analysis (X-ray powder diffraction, infrared absorption spectrometry, thermal analysis and chemical composition) to determine the structural formula of the Na-montmorillonite, and to clarify the effect of the introduction of the Al13 polycations between the clay layers on its physico-chemical and structural properties. Our results show that the strength of chromium retention increases with pH. This effect is more marked in pillared than in unpillared clays. It seems that the mechanism of fixing of the metallic cations on pillared clays is more complex than a simple cationic exchange and involves the surface groups of the pillars. In other words, chromium adsorption on pillared montmorillonite is more like adsorption on an amphoteric oxide surface (such as Al2O3) than on a non-pillared clay. Etude des facteurs contrôlant l'adsorption de Cr(III) sur des montmorillonites modifiées Résumé Nous avons examiné les possibilités de fixation de l'ion métallique Cr(III) sur une montmorillonite sodique et pontée. Les différentes analyses physico-chimiques (Rayons-X, Spectroscopie Infrarouge, Analyse Thermique Différentielle et composition chimique) ont permis d'une part, d'établir la formule structurale de l'argile sodique et d'autre part de mettre en évidence l'effet du pontage de l'argile par des polycations hydroxyaluminiques sur ses propriétés physico-chimiques et structurales. Nos résultats montrent que le pouvoir de rétention du chrome augmente avec le pH. Ce paramètre affecte davantage son comportement dans les argiles pontées. Il apparaît que le mécanisme de fixation du Cr(III) sur les argiles à piliers est différent d'un simple échange cationique. L'adsorption dans ce cas met en jeu les groupements de la surface des piliers. En d'autres termes, le mécanisme d'adsorption des cations du chrome sur une montmorillonite pontée se rapproche de l'adsorption sur une surface d'oxyde amphotère (tel que Al2O3) plutôt que l'adsorption sur une argile non pontée. [source] Neptunium uptake by serum transferrinFEBS JOURNAL, Issue 7 2005Isabelle Llorens Although of major impact in terms of biological and environmental hazards, interactions of actinide cations with biological molecules are only partially understood. Human serum transferrin (Tf) is one of the major iron carriers in charge of iron regulation in the cell cycle and consequently contamination by actinide cations is a critical issue of nuclear toxicology. Combined X-ray absorption spectroscopy (XAS) and near infrared absorption spectrometry were used to characterize a new complex between Tf and Np (IV) with the synergistic nitrilotriacetic acid (NTA) anion. Description of the neptunium polyhedron within the iron coordination site is given. [source] Neutron Activation Analysis, Atomic Absorption and X-Ray Fluorescence Spectrometry Review for 2003GEOSTANDARDS & GEOANALYTICAL RESEARCH, Issue 1 2005L. Paul Bédard This review for the year 2003 deals with three relatively well-established, mature, analytical techniques (neutron activation analysis, atomic absorption spectrometry and X-ray fluorescence spectrometry) that nevertheless remain very important for the characterisation of geological and environmental samples. Developments in neutron activation analysis included modification to the technique in relation to the determination of platinum-group elements, as well as consideration of sample size in ore grade estimation. A considerable body of literature was published on the application of atomic absorption spectrometry in the analysis of environmental samples. Many of these proposed technical and methodological improvements, notably in extraction procedures. X-ray fluorescence spectrometry saw developments in in situ analysis, synchrotron micro-XRF (,-SRXRF) and a confocal X-ray set-up for 3D elemental imaging. XRF technologies were used in the analysis of geological samples, reference materials, glasses, solutes and environmental materials. [source] Determination of Selenium Concentration in Sixty Five Reference Materials for Geochemical Analysis by GFAAS after Separation with Thiol CottonGEOSTANDARDS & GEOANALYTICAL RESEARCH, Issue 2-3 2001Luc Marin sélénium; SAA four graphite; séparation; matériaux géologiques de référence; coton thiol Selenium has been determined in sixty five geological reference materials of different origins by graphite furnace atomic absorption spectrometry. Samples were decomposed with a mixture of nitric and hydrofluoric acids. Selenium was reduced to SeIV with hydrochloric acid, and then fixed and separated from the matrix on thiol cotton. After digestion of the thiol cotton in hot nitric acid, the Se concentration was measured using palladium and magnesium nitrates as a matrix modifier. The limit of determination was 0.02 ,g g,1, the precision of the results (relative standard deviation of 3 to 8 replicates) varied from 2.6 to 17.7% with an average of 7.9% in the range 0.02-42.7 ,g g,1 and was similar to the value obtained for synthetic samples. Our results are in good agreement with available literature values. Le sélénium a été dosé sur 65 standards géochimiques de référence de différentes provenances par spectrométrie d'absorption atomique avec four graphite. Les échantillons ont été mis en solution par une attaque acide HNO3 -HF. Le sélénium a été réduit en SeIV avec de l'acide chlorhydrique, fixé et séparé de la matrice sur du coton thiol. Après décomposition du coton thiol par chauffage avec de l'acide nitrique, les concentrations en sélénium ont été mesurées en utilisant du nitrate de palladium et de magnésium comme modificateur de matrice. La limite de détermination est de 0.02 ,g g,1, la précision des résultats (écart type relatif sur 3 à 8 mesures) pour les standards géochimiques varie de 2.6 à 17.7% avec une moyenne de 7.9% dans la game 0.02-42.7 ,g g,1et est comparable à celle obtenue pour des échantillons synthétiques. Nos résultats sont en bonne concordance avec les résultats déjà publiés dans la littérature. [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] Rate constants for H + CH4, CH3 + H2, and CH4 dissociation at high temperatureINTERNATIONAL JOURNAL OF CHEMICAL KINETICS, Issue 11 2001J. W. Sutherland The Laser Photolysis-Shock Tube technique coupled with H-atom atomic resonance absorption spectrometry has been used to study the reaction, H + CH4 , CH3 + H2, over the temperature range, 928,1697 K. Shock-tube studies on the reverse of this reaction, CH3 + H2 , H + CH4, using CH3I dissociation in the presence of H2 yielded H-atom formation rates and rate constants for the reverse process over the temperature range, 1269,1806 K. These results were transformed (using well-established equilibrium constants) to the forward direction. The combined results for H + CH4 can be represented by an experimental three parameter expression, k = 6.78 × 10,21 T3.156 exp(,4406 K/T) cm3 molecule,1 s,1 (348,1950 K) that was evaluated from the present work and seven previous studies. Using this evaluation, disagreements between previously reported values for the dissociation of CH4 could be reconciled. The thermal decomposition of CH4 was then studied in Kr bath gas. The dissociation results agreed with the earlier studies and were theoretically modeled with the Troe formalism. The energy transfer parameter necessary to explain both the present results and those of Kiefer and Kumaran (J Phys Chem 1993, 97, 414) is, ,,,E,all/cm,1 = 0.3323 T0.7. The low temperature data on the reverse reaction, H + CH3 (in He) from Brouard et al. (J Phys Chem 1989, 93, 4047) were also modeled with the Troe formalism. Lastly, the rate constant for H + CH4 was theoretically calculated using conventional transition state theory with Eckart tunneling corrections. The potential energy surface used was from Kraka et al. (J Chem Phys 1993, 99, 5306) and the derived T-dependence with this method agreed almost perfectly with the experimental evaluation. © 2001 John Wiley & Sons, Inc. Int J Chem Kinet 33: 669,684, 2001 [source] Les fards rouges cosmétiques et rituels a base de cinabre et d'ocre de l'époque punique en Tunisie: analyse, identification et caractérisationINTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Issue 5 2001A. Alatrache Synopsis Natural antique colorants include mainly red pigments such as cinnabar and ochre. These archeological pigments were used especially as funeral and cosmetic makeup and are a material proof of handicraft activities and exchanges. The identification and characterization of a group of punic colorants, corresponding to samples discovered during excavations at several Tunisian archeological sites (Cartage, Ksour Essef, Kerkouane, Bekalta, Makthar, Bou Arada), were conducted using the least destructive analysis techniques such us scanning electron microscopy coupled to X-ray fluorescence microprobe, direct current plasma emission spectroscopy, atomic absorption spectrometry, Fourier transform infrared spectrometry and X-ray diffraction. Eleven natural red colorants from punic period were subject to this investigation and were compared to contemporary substances. Five colorants were cinnabar and the other six were ochre. Résumé Les colorants antiques naturels comportent principalement les pigments rouges tels que le cinabre et l'ocre. Ces pigments archéologiques ont été utilisés spécialement comme fards funéraires et cosmétiques, qui sont des témoins matériels d'activités artisanales et d'échanges. La caractérisation et l'identification d'un ensemble de colorants puniques correspondant à des échantillons découverts lors des fouilles sur divers sites de Tunisie (Carthage, Ksour Essef, Kerkouane, Bekalta, Makthar, Bou Arada) ont été conduites en employant des techniques d'analyse les moins destructives possibles telles que la microscopie électronique à balayage (MEB) couplée à une microsonde de fluorescence X (XRF), les spectrométries d'émission plasma à courant direct (DCP), d'absorption atomique (SAA) et infrarouge à transformée de Fourier (FTIR) et la diffraction aux rayons X (RX). Onze colorants naturels rouges puniques ont été soumis à l'étude et comparés avec des matières contemporaines. Cinq d'entre eux sont des composés de cinabre, les six autres des ocres. [source] Integration of magnetism and heavy metal chemistry of soils to quantify the environmental pollution in Kathmandu, NepalISLAND ARC, Issue 4 2005Pitambar Gautam Abstract Soil profiles of the Kathmandu urban area exhibit significant variations in magnetic susceptibility (,) and saturation isothermal remanence (SIRM), which can be used to discriminate environmental pollution. Magnetic susceptibility can be used to delineate soil intervals by depth into normal (< 10,7 m3/kg), moderately enhanced (10,7,< 10,6 m3/kg) and highly enhanced (, 10,6 m3/kg). Soils far from roads and industrial sites commonly fall into the ,normal' category. Close to a road corridor, soils at depths of several centimeters have the highest ,, which remains high within the upper 20 cm interval, and decreases with depth through ,moderately magnetic' to ,normal' at approximately 30,40 cm. Soils in the upper parts of profiles in urban recreational parks have moderate ,. Soil SIRM has three components of distinct median acquisition fields (B1/2): soft (30,50 mT, magnetite-like phase), intermediate (120,180 mT, probably maghemite or soft coercivity hematite) and hard (550,600 mT, hematite). Close to the daylight surface, SIRM is dominated by a soft component, implying that urban pollution results in enrichment by a magnetite-like phase. Atomic absorption spectrometry of soils from several profiles for heavy metals reveals remarkable variability (ratio of maximum to minimum contents) of Cu (16.3), Zn (14.8) and Pb (9.3). At Rani Pokhari, several metals are well correlated with ,, as shown by a linear relationship between the logarithmic values. At Ratna Park, however, both , and SIRM show significant positive correlation with Zn, Pb and Cu, but poor and even negative correlation with Fe (Mn), Cr, Ni and Co. Such differences result from a variety of geogenic, pedogenic, biogenic and man-made factors, which vary in time and space. Nevertheless, for soil profiles affected by pollution (basically traffic-related), , exhibits a significant linear relationship with a pollution index based on the contents of some urban elements (Cu, Pb, Zn), and therefore it serves as an effective parameter for quantifying the urban pollution. [source] Aluminum Content in Foods and Beverages Consumed in the Spanish DietJOURNAL OF FOOD SCIENCE, Issue 2 2000F.F. López ABSTRACT: A reliable and rapid method for determining aluminum content in foods and beverages was developed using electrothermal atomization-atomic absorption spectrometry (ETA-AAS) using previous optimization of the time-temperature program for the graphite furnace. The samples were subjected to acid mineralization with HNO3 and V2O5. The technique used slurries for assay in samples of dairy products. The detection limit was 4.0 pg. The mean recovery obtained ranged from 98.5% to 99.0%. The variation coefficient ranged from 3.2% to 5.2%. The results obtained ranged from 1.362 to 6.610 ,g/g in seafood, 0.171 to 29.688 ,g/g in vegetables, 19.560 to 70.100 ,g/g in olive oil, 0.424 to 6.430 ,g/g in dairy products and 25.600 to 58.057 ,g/g in stimulant drinks and infusions. This study contributes new data on the Al content of a variety of foods and beverages in Spain and such data are important for composition tables. The higher presence corresponded to seafood, vegetables and dairy products. Their contribution to Al dietary intake were estimated. [source] Fourier transform Raman spectroscopic study of pigments present in decorative wallpapers of the middle nineteenth century from the Santa Isabel factory (Vitoria, Basque Country, Spain),JOURNAL OF RAMAN SPECTROSCOPY, Issue 1 2002K. Castro One of the earliest wallpapers manufactured by the Santa Isabel factory (Vitoria, Basque Country, Spain) (1845) was found at the Torre de los Varona (near Vitoria) during restoration work on the building. As part of this cleaning and restoration work, the identification of the wallpaper's pigments was carried out by Fourier transform (FT) Raman spectroscopy. Fragments of paper were set in a sampler kit for planar surfaces. By moving the paper samples, it is possible to locate the laser beam's spot at the point that it is going to be analysed with a spatial resolution of about 0.5 mm. With this method it is possible to map a surface of several square centimetres without the need for an optical microscope. As FT-Raman analysis is totally non-destructive, the samples were restored and integrated with the whole wallpaper at the end of the analysis. Small particles of pigment were collected for the analysis of the pink and green colours by atomic absorption spectrometry (AAS). In both cases, the damage caused by the pigment sampling was minimal and non-visible. BaSO4, CaCO3, Pb3O4, PbCrO4, PbO, Prussian Blue, gypsum and an organic black pigment were detected. It is important to take into account the laser beam's penetrative power in order to interpret the spectra correctly. The identification of only eight pigments to make 12 different colours, mostly in two different shades, shows the ability of the wallpaper manufacturer to create a rich palette at low cost. This type of primitive industrial decorative work has become real artwork that it is necessary to preserve and restore. Copyright © 2002 John Wiley & Sons, Ltd. [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] Whole Blood Manganese Concentrations in Dogs with Congenital Portosystemic ShuntsJOURNAL OF VETERINARY INTERNAL MEDICINE, Issue 1 2010A.G. Gow Background: Manganese (Mn) is an essential mineral that is a cofactor for many enzymes required in the synthesis of proteins, carbohydrates, and lipids. Because hepatic clearance is essential in Mn homeostasis, conditions in humans resulting in hepatic insufficiency including cirrhosis and both acquired and congenital portosystemic shunting have been reported to result in increased blood Mn concentrations and increased Mn content in the central nervous system. Because Mn toxicity causes neurologic disturbances, increased Mn concentrations have been implicated in the pathogenesis of hepatic encephalopathy. Hypotheses: Dogs with congenital portosystemic shunts (cPSS) have significantly higher whole blood Mn concentrations than do healthy dogs or those with nonhepatic illnesses. Animals: Eighteen dogs with cPSS, 26 dogs with nonhepatic illnesses, and 14 healthy dogs. Methods: Whole blood Mn was measured by graphite furnace atomic absorption spectrometry. The diagnosis of cPSS was made by ultrasonography or during celiotomy either by visual inspection of a shunting vessel or portovenography. Results: Dogs with a cPSS had significantly higher whole blood Mn concentrations than did healthy dogs and dogs with nonhepatic illnesses. Whole blood Mn concentrations were not significantly different between healthy dogs and dogs with nonhepatic illnesses. Conclusion and Clinical Importance: Dogs with a cPSS have significantly increased whole blood Mn concentrations. Additional studies are warranted to investigate the role of Mn in cPSS-associated hepatic encephalopathy. [source] Transient elastography in the assessment of liver fibrosis in adult thalassemia patients,AMERICAN JOURNAL OF HEMATOLOGY, Issue 8 2010Mirella Fraquelli Transient elastography (TE) is a valuable noninvasive technique of measuring liver stiffness and a reliable tool for predicting hepatic fibrosis in patients with chronic liver disease. The role of TE in patients with ,-thalassemia has not been extensively investigated. The present study aimed to evaluate the role of TE in the assessment of hepatic fibrosis in 115 adult patients with ,-thalassemia major (TM) (#59) or intermedia (TI) (#56). TE was performed according to current practice. Histologic data were obtained in 14 cases. Liver iron concentration was assessed by atomic absorption spectrometry and T2* magnetic resonance. In patients with TM, the proportion of anti-HCV positive viremic patients, median serum ferritin levels, and TE values were significantly higher than in TI. In the group of 14 patients who underwent liver biopsy, a significant positive correlation was observed between liver stiffness and fibrosis stage (r = 0.73, P = 0.003). Severe fibrosis is diagnosed with a sensitivity of 60% and a specificity of 89%, whereas cirrhosis is detected with a sensitivity of 100% and a specificity of 92%. At multivariate analysis, the variables independently associated with TE were ALT, GGT, and bilirubin levels in both groups and, in patients with TM, HCV RNA positivity. In ,-thalassemia patients, TE is a reliable tool for assessing liver fibrosis even if the influence of iron overload has to be clarified. Am. J. Hematol. 85:564,568, 2010. © 2010 Wiley-Liss, Inc. [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 a second-generation portable blood lead analyzer in an occupational settingAMERICAN JOURNAL OF INDUSTRIAL MEDICINE, Issue 12 2007Noel V. Stanton MS Abstract Background A new blood lead testing instrument has qualities that make the instrument attractive for on-site testing of occupational lead exposures. This study evaluated the accuracy of the instrument when used in a manufacturing setting, and examined the impact of blood storage and shipment on results. Methods Venous blood specimens (n,=,121) were obtained and immediately analyzed on-site using the new instrument. They were then shipped to a reference laboratory and analyzed using electro-thermal atomization atomic absorption spectrometry (ETAAS), and retested using the new instrument. Results The cohort blood lead concentration averaged 40.1 µg/dl. Results obtained on the new analyzer with freshly collected blood averaged 38.7 µg/dl. The mean difference of 1.2 µg/dl on paired samples was not statistically significant. Following blood shipment and storage, results on the analyzer increased to an average of 42.4 µg/dl. The mean increase of 3.0 µg/dl on stored blood samples also failed to reach statistical significance. Under OSHA proficiency test acceptability requirements, 94% of the results had satisfactory agreement. Conclusions The new analyzer might be a useful tool for on-site monitoring of occupational lead exposures. The manufacturer's instructions should be adhered to with respect to specimen age and storage requirements. Am. J. Ind. Med. 50:1018,1024, 2007. © 2007 Wiley-Liss, Inc. [source] Determination of total urinary mercury by on-line sample microwave digestion followed by flow injection cold vapour inductively coupled plasma mass spectrometry or atomic absorption spectrometryRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 15 2002M. Bettinelli The total mercury content in urine was determined by inductively coupled plasma mass spectrometry with the so-called cold vapour method after on-line oxidative treatment of the sample in a microwave oven (FI-MW-CV-ICPMS). Use of a KBr/KBrO3 mixture, microwave digestion, and the final oxidation with KMnO4, assure the complete recovery of the organic forms of Hg which would be difficult to determine otherwise if using only the CV-ICPMS apparatus. Quantitative recoveries were obtained for phenyl Hg chloride (PMC), dimethyl Hg (DMM), Hg acetate (MA) and methyl Hg chloride (MMC). Use of automatic flow injection microwave systems (FI-MW) for sample treatment reduces environmental contamination and allows detection limits suitable for the determination of reference values. Since no certified reference materials were commercially available in the concentration ranges of interest, the accuracy of the proposed procedure has been assessed by analysing a series of urine samples with two independent techniques, ICP-MS and AAS. When using the FI-MW-CV-ICP-MS technique, the detection limit was assessed at 0.03µg/L Hg, while with FI-MW-CV-AAS it was 0.2µg/L Hg. The precision of the method was less than 2,3% for FI-MW-CV-ICP-MS and about 3,5% for FI-MV-CV-AAS at concentrations below 1µg/L Hg. These results show that ICP-MS can be considered as a "reference technique" for the determination of total urinary Hg at very low concentrations, such as are present in non-exposed subjects. Copyright © 2002 John Wiley & Sons, Ltd. [source] Problems in determination of skeletal lead burden in archaeological samples: An example from the First African Baptist Church populationAMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 4 2008L.E. Wittmers Jr. Abstract Human bone lead content has been demonstrated to be related to socioeconomic status, occupation and other social and environmental correlates. Skeletal tissue samples from 135 individuals from an early nineteenth century Philadelphia cemetery (First African Baptist Church) were studied by electrothermal atomic absorption spectrometry and X-ray fluorescence for lead content. High bone lead levels led to investigation of possible diagenetic effects. These were investigated by several different approaches including distribution of lead within bone by X-ray fluorescence, histological preservation, soil lead concentration and acidity as well as location and depth of burial. Bone lead levels were very high in children, exceeding those of the adult population that were buried in the cemetery, and also those of present day adults. The antemortem age-related increase in bone lead, reported in other studies, was not evidenced in this population. Lead was evenly deposited in areas of taphonomic bone destruction. Synchrotron X-ray fluorescence studies revealed no consistent pattern of lead microdistribution within the bone. Our conclusions are that postmortem diagenesis of lead ion has penetrated these archaeological bones to a degree that makes their original bone lead content irretrievable by any known method. Increased bone porosity is most likely responsible for the very high levels of lead found in bones of newborns and children. Am J Phys Anthropol, 2008. © 2008 Wiley-Liss, Inc. [source] Nitrite-Induced Methemoglobinaemia Affects Blood Ionized and Total Magnesium Level by Hydrolysis of Plasma Adenosine Triphosphate in RatBASIC AND CLINICAL PHARMACOLOGY & TOXICOLOGY, Issue 5 2009Md. Mizanur Rahman This study was performed on male Sprague,Dawley rats to which NaNO2 was injected (10 mg/kg i.p.) to induce methemoglobinaemia. Methemoglobin (MetHb) in blood was measured before (0 min.) and after 10, 30, 60 and 120 min. of NaNO2 injection. At respective time points, the tMg2+, blood ions and gases were measured by atomic absorption spectrometry and ion selective electrode, respectively. Haematological parameters were checked by automatic blood cell count, and blood films were observed under light microscope. Plasma ATP was measured by bioluminescence assay using a luminometer, and plasma proteins were measured by an automatic analyser. Blood cell count (RBC, WBC and platelet), haematocrit, and haemoglobin were found to be decreased with the advancement of MetHb concentration. With the gradual increase of MetHb concentration, the plasma ATP decreased and blood iMg2+ and plasma tMg2+ increased significantly as time passed by in comparison with the pre-drug values. A significant decrease of the ratio of ionized calcium to iMg2+, Na+ and increase of K+ was observed. In conclusion, NaNO2 -induced methemoglobinaemia is a cause of hydrolysis of plasma ATP which is responsible for the increase of blood iMg2+ and plasma tMg2+ in rats. [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] Noninvasive assessment of liver fibrosis in thalassaemia major patients by transient elastography (TE) , lack of interference by iron depositionBRITISH JOURNAL OF HAEMATOLOGY, Issue 3 2010Vito Di Marco Summary The correlation between liver stiffness, measured by transient elastography, liver fibrosis, using the histological METAVIR score, and iron overload, measured by atomic absorption spectrometry was evaluated in 56 homozygous-,-thalassaemics. Liver stiffness increased proportionally to liver fibrosis staging (r = 0·70; P > 0·001) independently of liver iron concentration (r = 0·01; P = 0·932). The area under the receiver-operating characteristic curve for prediction of cirrhosis was 0·997 (95% confidence interval [CI]: 0·925,1·000) with cut-off of 13 kPa with 100% sensitivity (95% CI: 69·0,100·0) and 95% specificity (95% CI: 84·2,99·3). Transient elastography is a reliable non-invasive tool for diagnosing advanced liver fibrosis in homozygous-,-thalassaemics, regardless of the degree of iron overload. [source] Preconcentration 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] | |||||||||||||||||||