M. Stoeppler's research while affiliated with National Institute of Standards and Technology and other places

Publications (208)

Chapter
EinleitungArsen in der UmweltQuecksilber und Methylquecksilber in der UmweltQualitätskontrolle und ReferenzmaterialienLiteratur
Chapter
IntroductionPhysical and Chemical Properties and Analytical Methods Sources, Production, Important Compounds, Uses, Waste Products and RecyclingDistribution in the Environment, in Foods and in Living OrganismsUptake, Absorption, Transport and Distribution, Metabolism and Elimination in Animals and HumansEffects on HumansHazard Evaluation and Limiti...
Chapter
In the course of an analytical procedure the next step after sampling (and if necessary homogenization and reduction to obtain appropriate subsamples) is the preparation of the material for the determination of analytes (elements, organometallic compounds, anions etc.).
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Sampling for subsequent trace analysis is doubtless by far the most crucial step in an analytical procedure. If not properly planned and practically performed by using appropriate sampling tools [1] with the utmost care and expertise [2–6], total – systematic as well as random – errors for sampling can range from a small percentage to several order...
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Trace elements occur in biological systems only in relatively small amounts, i.e. in the order of mg/kg or below. They have been part of the natural environment throughout historical times. Although trace elements such as selenium, iodine, molybdenum and cobalt are generally known to be physiologically essential they might have adverse effects on h...
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This chapter discusses the principles of reference materials for trace element analysis. Improved methods of analytical quality assurance and their consistent application by analysts everywhere, appear to be urgent requirements in trace element research. All aspects of quality assurance, both internal and external, need careful attention. The refer...
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This chapter discusses the role of Arsenic in the environment. Arsenic is present in igneous and sedimentary rocks and ores mainly in the form of sulphides, arsenides, and sulpharsenides. Weathering, volcanism, dissolution in water, biological and anthropogenic activities leads to arsenic emissions into the atmosphere, the terrestrial and aquatic e...
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This chapter discusses the various sample treatment of human biological materials. The quantitative analysis of human biological material is important to evaluate the concentrations of various elements within a range of concentrations in clinical specimens. The transformation of the preserved/sampled specimens to a form suitable for obtaining an er...
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This chapter discusses the basic principles and methods, starting with sampling, sample storage and sample treatment. These steps are important for each analytical procedure. Human specimens are analyzed for trace elements in order to find out whether there is a deficiency of an element or if there is excessive exposure to an element. When trace el...
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Feathers of selected bird species are used as pollution integrating biomonitors in areas of the German Environmental Specimen Bank. Lead, cadmium and mercury are analysed by Zeeman Solid Sampling AAS in feather vanes of selected bird species with different ecologies. In feather vanes there are quite different distribution patterns of lead and cadmi...
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The environmental specimen bank of the Federal Republic of Germany represents the modern form of a systematically designed archive for the preservative storage of selected environmental specimens. Major aims of environmental specimen banks are: (i) retrospective identification and quantification of environmental chemicals including those not known...
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The National Biomonitoring Specimen Bank at the National Institute of Standards and Technology applies a variety of techniques for extensive characterization of banked samples. To determine a large number of trace elements in small samples at low levels, instrumental neutron activation analysis has been combined with voltammetry. The two methods pr...
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The combined application of instrumental-, radiochemical- and prompt gamma neutron activation analysis to two spruce shoot materials from the German Environmental Specimen Bank (ESB) resulted in information on 50 elements, covering more than 50% of the total mass. Comparison of the element concentrations in the 'fingerprint' mode clearly indicated...
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Two new materials are introduced that might serve as useful aids for the harmonisation of analytical results. Spruce shoots, cryogenically homogenized and characterized for 50 elements from two sampling sites of the German Environmental Specimen Bank (ESB) are presented as possible third generation reference materials that might also act as calibra...
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Two concentration methods — HCl extraction and extraction followed by water vapour distillation — prior to anion exchange separation and cold-vapour atomic absorption spectrometry were used for the quantification of methyl mercury in a number of reference materials of biological and environmental origin with reference or certified total mercury con...
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An analysis using Certified Reference Materials (CRMs) together with routine samples is by far the best approach for quality control in multielement analysis of environmental samples. The selection of the correct CRM is thus the first important step for all reliable analysis. The chosen material should have a similar matrix, similar concentration o...
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Solid sampling graphite furnace ZAAS is very efficient for homogeneity testing because of the low sample intake with this method. A number of biological reference materials were investigated for heterogeneity with respect to the laboratory sampling error. It was observed that in some cases the investigated material appears to contain a distinct par...
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Harmonization of certified values in Reference Materials (RMs) can be carried out by applying nuclear analytical techniques to RMs of various matrix types and concentration levels. Although RMs generally should not be used as primary standards the cross evaluation of concentrations in RMs leads to better compatibility of reference values and thus t...
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This chapter discusses the crucial steps of trace analytical procedures ranging from sample collection, sample treatment, and instrumental techniques to the increasingly important approaches of chemical speciation and environmental mobility of metals and metal compounds in sediments and soils. It describes the application of analytical methods for...
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Re: Hense HW, Filipiak B, Novak L and Stoeppler M. Nonoccupational determinants of Mood leed concentrations in a general population. International Journal of Epidemiology 1992; 21: 753–62. The abstract should read as follows: We investigated the influence of various nonoccupational factors on blood lead levels (PbB) in a sample from the general pop...
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By using isotope dilution mass spectrometry with thermal ionization, TI concentrations were determined in sediments from six sampling positions of the River Elbe in the area of the former GDR (Bad Schandau, Dresden, Barby, Magdeburg, Werben/Havel and Cumlosen). For comparison, two samples from the River Rhine near Emmerich taken in 1978 and 1990 an...
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Methods are described for the speciation of arsenic and mercury in biological and environmental materials. For arsenic various methods were developed to distinguish between more or less toxic arsenic compounds and non-toxic compounds. For the determination of methylmercury a modification of the West procedure was applied for higher contents as well...
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Clinical evidence points to disturbed calcium metabolism in lead (Pb) intoxication. To further clarify the mechanisms involved, serum levels of 1,25(OH)2D3, receptors for 1,25(OH)2D3 as well as size and ultrastructure of parathyroid glands were examined in Wistar Kyoto rats exposed to 1% lead (Pb) acetate in drinking water for 10 weeks (short-term...
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Die zunehmende Belastung unserer Umwelt durch eine Vielzahl meist anthropogener chemischer Stoffe erfordert wirkungsvolle Kontroll- und Überwachungsmaßnahmen. Diese sollen sowohl eine zuverlässige Beschreibung des Ist-Zustandes als auch die Aufklärung ökochemischer und ökotoxikologischer Wirkungen ermöglichen. In diesem Zusammenhang ist die Erkennu...
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Eine Umweltprobenbank (UPB) ist ein Archiv von regelmäßig gesammelten repräsentativen Umwelt- und Humanproben. Durch extrem tiefe Temperaturen ist gewährleistet, daß die Proben auch bei Langzeitlagerung keinen chemischen Veränderungen unterliegen. Das so konservierte Material dient der retrospektiven und prospektiven Erkennung und Bewertung der Umw...
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For evaluation and homogeneity estimation in several plant reference and candidate reference materials from different sources, including two 2nd generation environmental specimen bank (ESB) candidate reference materials, prepared by cryogenic milling of fresh spruce shoots, solid sampling graphite furnace AAS (SSGFAAS) was used. The results obtaine...
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Potentiometric stripping analysis (PSA) has the potential for rapid determination of cadmium and other metals. This method has received increasing attention because of some advantageous properties such as no interference by oxygen, less susceptibility to adsorption phenomena, inexpensive and simple instrumentation. Increasing interest in the contin...
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The Subcommittee on Cadmium of the IUPAC Clinical Chemistry Division's Commission on Toxicology performed two cooperative interlaboratory surveys in 1983 and 1985. In the first survey, performed in 1983 with liquid human and lyophilized synthetic urines, 35 laboratories from 13 countries participated. In the second survey, performed in 1985 with tw...
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The Subcommittee on Cadmium of the IUPAC Clinical Chemistry Division's Commission of Toxicology performed two cooperative interlaboratory surveys from 1979 to 1981 for the determination of cadmium in whole blood. The goal was to study the suitability of a possible standardized method. This paper presents the results of two pilot studies and the two...
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Using Isotope Dilution Mass Spectrometry (IDMS) with thermal ionization, thallium concentrations were determined in reference materials from NIST and BCR, from other sources, and reference materials from the German Environmental Specimen Bank. 203Tl spike solution is applied for the isotope dilution technique. Thallium concentrations in the investi...
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The relatively high concentrations of lead and cadmium in feather vanes and the morphological structure of the feather makes it possible to use Zeeman Solid Sampling AAS as an ideal method for analysing microsamples of defined parts of the feather vane. In different feathers of different bird species there is an increase of lead and cadmium concent...
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In an effort to bring to the analytical community new natural matrix reference materials (RM's) for elemental composition quality control, ten new agricultural/food candidate reference materials prepared previously, were characterized for homogeneity. The materials include bovine muscle powder, whole egg powder, corn bran, microcrystalline cellulos...
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The degradation of biological sample materials with 69% nitric acid was studied at 180°C in closed PTFE crucibles. Of the organic matrix constituents present in significant concentrations in the biological samples, merely some amino acids (phenylalanine, histidine, tryptophan, methionine) and the double unsaturated fatty acid linoleic acid provide...
Chapter
The determinations of cadmium in biological materials were mainly performed by colorimetry. With the exception of radiochemical neutron activation analysis (NAA), cadmium is sensitive but not used as a rapid routine screening technique. These methods typically had absolute detection limits of the order of 1 μg of cadmium. Thus, if lower levels had...
Chapter
There is an urgent demand for reliable and rapid analysis of trace elements in biological materials. The most important are metals and metalloids that are considered as essential, toxic or possibly toxic to man, animals, and plants. In conjunction with similar analytical demands from other research branches, this situation has stimulated in recent...
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After the pressure decomposition of biological sample materials with 69% nitric acid at 180°C, organic decomposition products frequently remain, leading to interference effects during inverse voltammetric trace metal determination. It is shown by the example of the determination of Zn, Cd, Pb and Cu by inverse square-wave voltammetry that the inter...
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During the degradation of biological materials under pressure with 69% nitric acid at 180°C the organic matrix constituents are completely mineralized, with a few exceptions. Apart from sample constituents that occur in such low concentrations that their degradation products do not make a significant contribution to the organic residue, only five s...
Article
Concentrations of Zn, Cd, Pb, Cu and Hg were determined in sediments (grain-size fraction < 75 μm) from different parts of the Adriatic Sea. The results were compared with data obtained in sediments of similar granular composition by other authors concerned with pollution problems in the Adriatic Sea.Data obtained and summarized in the present work...
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Zusammenfassung Mit standardisierten Habicht-Mauserfedern läßt sich die Schwermetallbelastung von Landschaftsausschnitten repräsentativ erfassen, wie der Vergleich mit auf physikalisch-technischem Weg ermittelten Depositionsraten aus dem gleichen Untersuchungsgebiet bestätigt. Zwischen den Cadmium-, Blei- und Kupfergehalten in standardisierten Habi...
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Blood lead (Pb) and urinary Pb before and after i.v. infusion of 1 g of Na2Ca EDTA were determined (atomic absorption) in 46 control subjects and 91 patients with various stages of renal failure (median serum creatinine 2.5 mg dl-1). Under baseline conditions, patients with renal failure had higher blood Pb levels (112 ng ml-1, range 44–272 vs. 76;...
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The lead, cadmium and zinc in untreated blackbird (Turdus merula L.) feathers is predominantly of exogenous origin. The endogenous concentration is of minor importance. The degree of surface metal pollution depends on exposure time. The exogenous fraction of heavy metals cannot be completely removed by washing procedures. The difference between was...
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A method for the determination of extremely low levels of arsenic by hydride AAS is presented. It is based on hydride preconcentration in a quartz tube at liquid nitrogen temperatures under carefully evaluated and optimized experimental conditions, followed by rapid heating up to 100 C and measurement in a heated quartz cell. Under the given experi...
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Some parameters affecting the accuracy of various approaches to methylmercury (MeHg) determination in biological and environmental samples were studied. Different isolation techniques (ion-exchange, extraction, volatilization, distillation) and final measurement via cold vapour atomic absorption spectroscopy (CV AA) or gas chromatography (GC) were...
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Cobalt, chromium and nickel containing alloys are frequently used for orthopaedic implants and prostheses in spite of the increasing number of reports dealing with reactions of intolerance to these metals. Any implant introduced into the human organism undergoes at least two strokes: physico-mechanical owing to the environment of the site of implan...
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Das Institut für Angewandte Physikalische Chemie (ICH-4) der Kernforschungsanlage (KFA) Jülich befaßt sich seit Anfang der 70er Jahre mit Umweltanalytik und Umweltchemie. Bereits seit 1973 beteiligte es sich an einem vom Bundesministerium für Forschung und Technologie (BMFT) geförderten Programm, das neben der Neu- und Weiterentwicklung präziser Be...
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Reliable analytical approaches for the determination of cadmium at trace and ultratrace levels in numerous materials either as routine or reference methods are the voltammetric modes differential pulse anodic stripping voltammetry (DPASV) and square wave voltammetry (SWV). The potential of these methods, partly in direct comparison, in some cases a...
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Earthworm samples (Lumbricidae) from three different sampling sites in the Federal Republic of Germany were collected for the German Environmental Specimen Bank (ESB). Subsamples of the cryohomogenized material from two annual samplings were analyzed by Instrumental Neutron Activation Analysis (INAA) and mean values are presented in the logarithmic...
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During the last decade, due to remarkable progress in analytical expertise and instrumentation, many sources of error from sampling to analytical determinations of trace metals have been identified and corrected in recent studies. This has led to a dramatic decrease of concentration levels considered as normal in biological and environmental materi...
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Based on high-pressure ashing, the potential to determine some trace metals (Zn, Cd, Pb, Cu, Ni, Co, Al, Tl, Cr, Fe) by anodic or cathodic stripping voltammetry in the square wave (SWV) and differential pulse modes (DPASV) is described. In comparison to the differential pulse mode, the square wave mode shows advantages for cathodic stripping and fo...
Chapter
Since approximately 1975 a steady progress in trace analytical chemistry is to be noticed. This is due to a remarkable methodological improvement which has led to the identification and elimination of many sources of error from sampling and sample treatment preceeding the analytical determination step. Results of these improvements are significantl...
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The long-term storage behavior of mercury and methylmercury at ng 1−1 levels in sea water was studied at pH 4.0, 6.0, 8.0 and 10.0, and with 2% (v/v) hydrochloric or nitric acid added. Partial complexation and disappearance of mercury and methylmercury were observed; some of the lost mercury became detectable (by cold-vapour atomic absorption spect...
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Extensive surveys were made to establish the concentrations of several metals (Zn, Cd, Pb, Cu and Hg) in various marine organisms from different parts of the Adriatic Sea in the period from 1979 to 1985. The results obtained are based on analyses which were performed in conjunction with carefully tested procedures. Proper sampling, sample storage,...
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The homogeneity of lead and cadmium in reference materials was investigated by solid sampling GFAAS. The following materials were comparatively analyzed: Standard reference materials from NBS, Washington 1567 Wheat flour, 1568 Rice flour and 1577a Bovine liver, certified reference materials from BCR, Brussels, No 63 Milk powder, No 184 Bovine muscl...
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In the original intercomparisons two of the IAEA's reference materials, milk powder A-11 and animal muscle H-4, gave unsatisfactory results, with a wide spread of values for many trace elements of interest, and subsequently the recommended values for Cu and Mn in A-11 have been questioned. In the present work, efforts to improve the status of these...
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Full-text available
Some of the factors that can influence the precision, sensitivity and accuracy of the determination of aluminium in serum and plasma by graphite furnace atomic absorption spectrometry are identified. These factors can broadly be divided into two groups, namely: instrumental conditions and sample pre-treatment. Variations in the above parameters can...
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The comparability of analytical results from different laboratories requires accurately known concentrations in the applied standards. Dilution effects of different multielement synthetic standard solutions have been studied by measuring 10–12 different concentrations of the same solution. Peak area comparison of four Certified Reference Materials...
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The efficiency of wet digestion with nitric acid at 320 °C by use of the high pressure asher published by Knapp [10] has been studied with a series of biological materials which usually are only incompletely decomposed by pressure digestion at 170 °C in PTFE vessels. For that purpose the residual carbon content of the digestion solution was determi...
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The homogeneity of lead and cadmium in reference materials was investigated by solid sampling GFAAS. The following materials were comparatively analyzed: Standard reference materials from NBS, Washington 1567 Wheat flour, 1568 Rice flour and 1577a Bovine liver, certified reference materials from BCR, Brussels, No 63 Milk powder, No 184 Bovine muscl...
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From June 1979 to June 1980 the accumulation of zinc by the mussel Mytilus galloprovincialis and the oyster Ostrea edulis, from the Limski Kanal on the west coast of Istria, SR Croatia, Yugoslavia, was determined. The distribution of zinc within tissues and organs of mussels and oysters of the same length was related to the zinc concentration in th...
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The wet deposition of mercury and methylmercury was monitored for a period of 1 year at selected areas in the Federal Republic of Germany. These areas represented an industrial zone, an urban area, a rural area close to the industrial zone and other rural areas. The wet deposition of mercury was very much dependent on the collection area; the wet d...
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The long-term stability of Hg2+ and methylmercury chloride (MeHgCl) and the decomposition of MeHgCl under various conditions were investigated. In the absence of light MeHgCl does not decompose to Hg2+, even in the presence of 25% acids, during a period up to 3 d. MeHgCl is not easily decomposed by heating in the presence of 50% acid concentrations...
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The internal structure of yttrium-doped tetragonal zirconia powder compact was characterized using the immersion liquid technique, mercury porosimetry, scanning electron microscopy, and a compaction test. The specimens examined were prepared by pressing spray-dried granules at various pressures from 5–600 M Pa. The immersion liquid technique had nu...
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Ultratrace analysis of mercury in rain water has been investigated, including recovery of ionic mercury with the addition of acids, treatment and storage and stability studies of mercury in rain water. Recovery of ionic mercury from rain water samples increased with increased acid concentrations and increased substantially with UV-irradiation. Reco...
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Interlaboratory cooperative studies have been conducted under the auspices of the IUPAC Commission on Toxicology to establish concentrations of biological important trace elements in commercially available lyophilized human serum, whole blood and urine. The main objective was to arrive at consensus concentration values in order to establish these m...
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Following an introduction into the principle of an environmental specimen bank the philosophy of production and application of lyophilized and fresh reference materials on the basis of surplus materials of the environmental specimen bank (ESB) in the Federal Republic of Germany or very similar materials is discussed. Subsequently a description is g...
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A rapid and extremely sensitive method for the separation of inorganic mercury (Hg) from methylmercury (MeHg) and the simultaneous determination of both compounds by CVAAS has been developed. The determination limit of the total procedure for MeHg is approximately 0.2 μg/kg for solids, 0.1 μg/kg for biological fluids like blood and urine, and 0.2 n...
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Following pressure digestion with nitric acid and pre-treatment with hydrofluoric acid for chromium in silica-containing materials, lead, chromium and copper are determined in plant materials by graphite furnace atomic absorption spectrometry with furnace programmes designed to keep the analysis time to a minimum, consistent with good accuracy and...
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The state-of-the-art of methodology for cadmium analysis in biological and environmental materials on the basis of recent progress is discussed. There is a remarkable gain in sensitivity and reliability for atomic spectroscopy mainly for graphite furnace techniques but to some extent also for flame atomic absorption with Zeeman background correctio...
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A long-term study within the pilot environmental specimen bank programme of the Federal Republic of Germany on arsenic levels in coastal and open seawater and their reflection in the brown seaweed (Fucus vesiculosus) has been performed. Dissolved arsenic was on average 0.76 (range 0.45–1.11) μgl−1 for 17 sampling stations in the Baltic Sea, whereas...
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Urinary excretion of lead (Pb) was measured in the basal state and following the infusion of EDTA (1g of calcium disodium edetate) in healthy German controls and in patients with chronic renal failure with and without gout. When evaluated with Zeeman-compensated atomic absorption spectroscopy using the L'vov platform and urine pretreated with nitri...
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Comparatively high sulphur contents in brown algae (Fucus vesiculosus) cause interferences in the determination of lead by Graphite Furnace Atomic Absorption Spectrometry (GFAAS). These cannot always be eliminated by the application of the L'vov platform, matrix modifiers recommended for lead as (NH4)2HPO4 and Mg(NO3)2, Zeeman-effect background cor...
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An international co-operative blood-lead interlaboratory survey was conducted based on lyophilised bovine blood samples with different endogenous lead contents. The samples were prepared from whole blood of a non-exposed cow and another fed with a single dose of lead acetate trihydrate. The mean values computed for the two samples analyzed by 25 pa...
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A procedure is described for the direct determination of cadmium and lead in whole milk, skim milk, condensed milk, and human milk. Using a Perkin-Elmer 5000 Z instrument with HGA 500 and L'vov platform and by application of oxygen ashing at approx. 600 degrees C, determination limits of approx. 0.02 microgram/l and 0.7 microgram/l for cadmium and...
Article
A procedure is described for the direct determination of cadmium and lead in whole milk, skim milk, condensed milk, and human milk. Using a Perkin-Elmer 5000 Z instrument with HGA 500 and L'vov platform and by application of oxygen ashing at approx. 600 C, determination limits of approx. 0.02 g/l and 0.7 g/l for cadmium and lead, respectively, are...
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Es wird ein Homogenittsfaktor fr pulverisierte Feststoffproben definiert und statistisch begrndet. Diese Kenngre kann mit ZAAS-Feststoffanalyse ermittelt werden. Am Beispiel von NBS Orchard leaves wird die Bestimmungsmethode und die Aussagekraft des relativen Homogenittsfaktors demonstriert. Es wurden Homogenittsfaktoren fr einige Referenzmateriali...
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Full-text available
The behaviour of the aluminium absorbance signal obtained from standard uncoated and pyrolytically coated tubes, and the L'vov platform inserted into a pyrolytically coated tube was examined in the presence of three inert sheath gases, hydrogen and various chemical modifiers. Methods of calibrating the spectrophotometer using each furnace type are...
Article
Cadmium (Ordnungszahl 48, Atomgewicht 112,4) steht in der 2. Nebengruppe des Periodensystems der Elemente; es tritt stets in zweiwertiger Form auf. Die Verbindungen des Cadmiums sind im allgem. leicht löslich. (Ausnahmen: Cadmiumsulfid, Cadmiumcarbonat, Cadmiumfluorid und Cadmiumhydroxid; letzteres löst sich jedoch leicht unter Komplexbildung in Am...

Citations

... It can be seen in Table 1 that anthropogenic sources of heavy metal pollution involve agricultural activities, such as the application of pesticides and herbicides, contaminated irrigation water, utilization of municipal waste for fertilization purposes [1,20]. Additionally, the anthropogenic source also includes waste disposal in farmland, mining activities, smoking, traffic emissions, the discharge of sewage, and building materials like paints [21,22]. The previous findings from studies carried out in Indonesia reported that heavy metals released into the environment by human activities in Indonesia cities are mainly from Industrialization, waste disposals, and agricultural activities [23]. ...
... All samples were digested with a mixture of nitric and perchloric acid by a hot plate method. Mercury analyses were performed by cold vapour atomic absorption spectrometry (CVAAS) with detection limit of 0.001 mg kg , for solid samples [3]. ...
... The plasma samples were pretreated before analysis by acid digestion in quartz vessels. The digested solutions were kept in a polyethylene vessel at -4~ until analysed by stripping electro-analytical techniques (Adeloju et al. 1985;Niirnberg 1981;Renman et al. 1986;Stoeppler 1988;Pinilla et al. 1995). ...
... This might be true if the other factors affecting arsenic concentration in wines are similar. Burow et al. (1988) investigated total arsenic concentrations in wines from different regions in Germany. The wines from Rheinhessen and Rheinpfalz had apparently higher arsenic concentrations (7.2 and 8.7 ppb) on average than those from the other regions (averagely 6.0 ppb), which coincides well with the concentrations of bioavailable arsenic in soils (Burow et al., 1988). ...
... Ni, Cr and Co were present at high concentrations throughout the ría, especially in the ZI and MZ. The Ni and Cr concentrations were 10 to 20 times higher, and the Co concentration was two times higher than the mean reference values suggested for marine sediments (Stoeppler, 1992;Turekian and Wedepohl, 1961) and than the values observed in marine sediments in other parts of Galicia (e.g. Ría de Ferrol, Vigo and Arousa; Table 2). ...
... Ni contamination can result in lesser gas absorbance in gills and may be fatal to fish because of oxygen deficiency. Since Ni is easily absorbed by air particles, Ni usually is prone to cause cancer to respiratory organs such as the lung (Stoeppler and Optapczuk, 1992). Ni concentration of 0.7 µg/g is considered potentially lethal to fish (Lemly, 1993). ...
... Information about the oxidation state of trace elements is as important to know as its chemical structure. It has been reported that the same metal ion may possess different levels of toxicity in its various oxidation states, which are responsible for their different physico-chemical and biological activities [7]. Speciation analysis of toxic heavy metals has special importance due to its impact on environmental chemistry, ecotoxicology, clinical toxicology and food industry. ...
Citing chapter
... The process of water eutrophication depends not only on nutrient concentrations, but also on their ratio. A C:N:P ratio of 40:7:1 favours eutrophication; hence, phosphorus is often the limiting element and its control is of prime importance in reducing the accelerated eutrophication of fresh waters [55]. Ingestion of high levels of phosphorus interferes with the metabolism of calcium and results in bone loss in both humans and animals. ...
... It was followed by the addition of 5.0 mL of HClO 4 in the Erlenmeyer flask with subsequent heating to a soft boil until white dense fumes evolved. The clear solution thus obtained was transferred to 50-mL volumetric flask, and the final volume was adjusted by doubly distilled water [7,[24][25][26]. Every care was taken to eliminate the chances of contamination of the samples during processing and preparation. ...
... Different aliquots of samples were further diluted to appropriate concentrations with 1 . 5% HCl (Merck, supra pure) and analysed for total arsenic by hybrid generation atomic absorption spectrophotometry (Stoeppler & Vahter, 1994). The limitation of detection was around 0 . ...