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Analytical and Bioanalytical Chemistry (v.372, #3)
No Title by Zhifang Chai; Xueying Mao; Zhaohui Hu; Zhiyong Zhang; Chunying Chen; Weiyu Feng; Sumin Hu; Hong Ouyang (pp. 407-411).
Recent achievements in speciation studies of trace elements in the biological and environmental sciences by nuclear analytical techniques, mainly molecular activation analysis, position-sensitive spectrometry with a variety of exciting sources, and synchronous radiation-based analytical techniques (although radioisotope or enriched stable isotope-based speciation techniques are also used), particularly in our laboratory, are outlined. In this paper the merits and drawbacks of the nuclear analytical techniques are discussed, as are reagent blanks, contamination, and artifacts.
Keywords: Nuclear analytical techniques Chemical speciation Trace elements
No Title by Andrea-Nicole Richarz; Peter Brätter (pp. 412-417).
A speciation analysis of protein-bound elements in the cytosol of human brain was achieved by size exclusion chromatographical separation of the biomolecules and on-line detection of the metal profiles in the eluate by hyphenated inductively coupled plasma–mass spectrometry. Post-mortem samples from Alzheimer's disease brains and from brains of a control group were investigated to elucidate changes in the trace element distribution during the pathological process.Special attention was paid to the metallothioneins (MT) – cysteine-rich, metal-binding proteins of low molecular weight, existing in several isoforms. The isoform MT-3 is found especially in the brain and has a growth inhibition function on neurons.The MT peaks were identified in the element profiles. For this purpose, the metal binding capability and the heat stability of MT were taken into consideration. For verification, a comparison with pure MT-3 was carried out and further biochemical and analytical methods were applied to the fractions of the chromatographical run.A comparison between Alzheimer's disease and control brains showed a significant difference concerning the MT-1/-2 and MT-3 metal levels, leading to the assumption that there were oxidative processes having taken place in the Alzheimer's brain samples.
Keywords: HPLC-ICP-MS Metallothionein-3 Brain Alzheimer Oxidative processes Speciation
No Title by K. Hirose; M. Aoyama (pp. 418-420).
Concentrations of particulate and dissolved plutonium in seawater were determined together with strong organic ligands (SOL) in particulate matter (PM). The concentration of particulate 239,240Pu in surface waters of the Western North Pacific ranged from 0.03 to 0.3 mBq m–3 during the period from 1987 to 1997. The percentage of particulate Pu to total Pu in seawater was less than 10% in surface waters, whereas its portions were less than 1% in deep waters. In order to characterize particulate Pu in seawater, the relationships between particulate Pu, dissolved Pu and SOL concentrations in surface PM were examined. The result reveals that particulate Pu was linearly related to the SOL concentration independent of dissolved Pu concentration. Mass balance analysis suggests that a dominant chemical form of Pu in surface PM, which may exist as Pu(IV), is a complex with strong organic ligands in PM.
Keywords: Speciation Plutonium Seawater Complexation Particulate matter Organic ligand
No Title by W. Windisch (pp. 421-425).
Variations in the chemical speciation of dietary trace elements can result in the provision of different amounts of these micronutrients to the organism and might thus induce interactions with trace-element metabolism. The chemical species of Zn, Fe, Cu, and Mn can interact with other components of the diet even before reaching the site of absorption, e.g. by formation of poorly soluble complexes with phytic acid. This might considerably modify the amount of metabolically available trace elements; differences between absorptive capacity per se toward dietary species seems to be less important. Homeostasis usually limits the quantities of Zn, Fe, Cu, and Mn transported from the gut into the organism, and differences between dietary species are largely eliminated at this step. There is no homeostatic control of absorption of Se and I, and organisms seem to be passively exposed to influx of these micronutrients irrespective of dietary speciation. Inside the organism the trace elements are usually converted into a metabolically recognizable form, channeled into their biological functions, or submitted to homeostatically controlled excretion. Some dietary species can, however, be absorbed as intact compounds. As long as the respective quantities of trace elements are not released from their carriers, they are not recognized properly by trace element metabolism and might induce tissue accumulation, irrespective of homeostatic control.
Keywords: Speciation Homeostasis Bioavailability Zinc Iron Copper Manganese Selenium Iodine
No Title by Chunying Chen; Jiujiang Zhao; Peiqun Zhang; Zhifang Chai (pp. 426-430).
Speciation of Se-containing proteins in the subcellular fractions of human liver was studied by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) followed by hydride generation-atomic fluorescence spectrometric (HG-AFS) detection. It was found that about 24 kinds of Se-containing proteins existed in subcellular fractions of normal human liver. The molecular weights (MW) of the subunits were mostly in the range 20–30 kDa and 50–80 kDa. Major Se-containing protein fractions at 61 kDa and 21 kDa are probably selenoprotein P and glutathione peroxidase, respectively. The 54 kDa protein is probably a thioredoxin reductase, which is presented in nuclei, mitochondria, lysosome, microsome and cytosol. We noticed that the Se-containing protein with the lowest MW of 9.3 kDa only existed in lysosome. Most of the proteins have not been identified and would require further investigation to characterize them. The specific subcellular distributions of different Se-containing proteins suggest that they could play important biological roles in each organelle.
Keywords: Se-containing proteins Gel electrophoresis Speciation HG-AFS Human liver
No Title by A. Kamnev; L. Antonyuk; V. Smirnova; O. Serebrennikova; L. Kulikov; Yu. Perfiliev (pp. 431-435).
57Co emission Mössbauer spectroscopy (EMS) allows the chemical state of cobalt, as influenced by its coordination environment, to be monitored in biological samples at its physiological (trace) concentrations. To draw attention to EMS as a valuable tool for speciation of cobalt in biocomplexes, the process of cobalt(II) metabolism in cells of the plant growth-promoting rhizobacterium Azospirillum brasilense Sp245 was investigated using EMS of 57CoII-doped bacterial cells. EMS measurements also showed 57CoII-activated glutamine synthetase (GS, a key enzyme of nitrogen metabolism, isolated from this bacterium) to have two different cobalt(II) forms at its active sites, in agreement with data available on other bacterial GSs. Chemical after-effects following electron capture by the nucleus of the parent 57CoII during the 57Co→57Fe transition, which contribute to the formation of a stabilised daughter 57FeIII component along with the nucleogenic 57FeII forms, are also briefly considered.
Keywords: Emission Mössbauer spectroscopy Cobalt (II) Azospirillum brasilense Bacterial cells Glutamine synthetase Enzyme active sites
No Title by I. Klich; L. Wilding; L. Drees (pp. 436-443).
Electron microscopic techniques, including scanning electron microscopy (SEM), transmission electron microscopy (TEM), and electron probe microanalyses (EPMA), were used to evaluate metal species and mineralogical phases associated with metal-bearing contaminated soil and industrial wastes that have been solidified and stabilized with Portland cement. Metals present in the wastes included arsenic, barium, cadmium, chromium, copper, lead, nickel, and zinc. In addition, mineral alterations and weathering features that affect the durability and containment of metals in aged remediated wastes were analyzed microscopically. Physical and chemical alteration processes identified included: freeze-thaw cracking; cracking caused by the formation of expansive minerals, such as ettringite and thaumasite; carbonation; and the movement of metals from waste aggregates into the surrounding cement matrix. Preliminary results show that although the extent of degradation after 6 years is considered slight to moderate, evaluations of durability and permanence of metals containment cannot be based on leaching and bulk chemistry analyses alone. The use of electron microscopic analyses is vital in studies that evaluate trace metal and mineral species and that attempt to predict the long-term performance of metal containment in solidified and stabilized wastes.
Keywords: Speciation Wastes, remediated Electron microscopy Trace methods Metals
No Title by B. Michalke; H. Witte; P. Schramel (pp. 444-447).
Investigations are described to extract Se-species from a bacterial sample. The five extraction methods investigated were: hot water, protease, lysozyme, lysozyme-protease, and HCl hydrolysis. The extraction efficiency was determined by comparing the total amounts of selenium in the sample after pressure digestion with the amounts extracted by the different methods described. Efficiencies were found to be only 1% (hot water), ca. 8% (protease, HCl hydrolysis) or ca. 12% (lysozyme, lysozyme-protease). The Se-peak patterns were compared after investigating the extracts with strong anion exchange chromatography–inductively coupled plasma mass spectrometry (SAX–ICP–MS). Most promising were the lysozyme-assisted procedures, which showed the highest diversity of species. Here, in the protease-lysozyme approach, the protease seemed to break down species that had been extracted by lysozyme from the bacterial wall (murein sacculus). The other approaches seemed not to extract many species. Hot water extraction was completely unsuitable, extracting only low amounts of a single, unknown species.
Keywords: Selenium Speciation Extraction procedures Species pattern
No Title by Adrian A. Ammann (pp. 448-452).
Biogenic (e.g. phytochelatins, porphyrins, DOM) as well as anthropogenic (e.g. NTA, EDTA, phosphonates) chelators affect the mobility and cycling of heavy metals in environmental waters. Since such chelators can form strongly bound anionic heavy metal complexes that are stable and highly mobile, anion-exchange chromatography coupled to ICP–MS was investigated. A narrow bore HPLC system was connected to a micro concentric nebuliser for in-line sample introduction. A new chromatographic procedure based on a synthetic hydrophilic quaternary ammonium anion exchanger in combination with nitrate as a strong eluent anion, and gradient elution, provided high separation selectivity and a large analytical window. Low detection limits (nmol L–1) were achieved by on-column matrix removal and sample preconcentration. This allowed the method to be successfully applied to different environmental research areas. In ecotoxicological studies of heavy metal effects on algae low concentrations of metal EDTA complexes were determined in nutrient solutions without interference from high (buffer) salt concentrations. In groundwater, infiltrated by a polluted river, mobile metal EDTA species were observed. In river water of different pollution levels beside CuEDTA other anionic Cu-complexes were found in nmol L–1 concentrations.
Keywords: Gradient anion-exchange chromatography Metal chelates Metal speciation Environmental water
Investigation of the response of wood-rotting fungi to copper stress by size-exclusion chromatography and capillary zone electrophoresis with ICP MS detection by Véronique Vacchina; Petr Baldrian; Jiri Gabriel; Joanna Szpunar (pp. 453-456).
A method based on the coupling of size-exclusion chromatography (SEC) with inductively coupled plasma mass spectrometry (ICP MS) was developed for screening the changes in the bioligand composition of wood-rotting fungi as a function of their exposure to copper stress. Strains of four different species of wood-rotting fungi: Phanerochaete chrysosporium, Schizophyllum commune, Daedalea quercina and Pleurotus ostreatus were examined. Only one, namely Ph. chrysosporium, showed any significant difference in terms of the fingerprint of Cu-binding ligands between control and exposed cells which suggest trapping of Cu(II) by cell walls as the only resistance mechanisms. In the case of Ph. chrysosporium the bioinduction of a new Cu-binding ligand was demonstrated. The presence of a new compound in the SE chromatographic fraction of interest was confirmed by CZE–ICP MS. Attempts to identify the new compound by electrospray MS/MS failed because of insufficient sensitivity.
Keywords: Heavy-metal stress wood Rotting fungi HPLC, ICP MS CZE, ICP MS Coupled techniques
No Title by Shona McSheehy; Pawet Pohl; Dinoraz Vélez; Joanna Szpunar (pp. 457-466).
An analytical strategy was developed for the characterization of arsenic species in a Laminaria algae. The approach was based on multidimensional liquid chromatography (LC) including sample extract cleanup by size-exclusion LC, separation of arsenic species by anion-exchange LC, verification of the chromatographic purity of arsenic-containing fractions, and their further purification, if necessary, by reversed-phase (RP) HPLC. The complementarity of ICP MS, used as the chromatographic detector, and ES MS/MS, employed for the identification of the peaks observed, was demonstrated. The species found were: arsenosugar A 11.7±0.5 µg g–1, AsV 10.9±2.1 µg g–1, arsenosugar B 2.22±0.07 µg g–1, arsenosugar D 1.5±1.2 µg g–1, a newly detected arsenosugar 1.13±0.07 µg g–1, arsenosugar C 0.61±0.04 µg g–1, DMA 0.42±0.02 µg g–1 and these accounted for >99% of the arsenic present. The identities of all the species, except the newly detected compound, were doubly checked by matching the retention times of chromatographically pure (after the 3rd LC dimension) species with standards and by ES MS/MS.
Keywords: Speciation Arsenic Algae Liquid chromatography
No Title by Ewa Dabek-Zlotorzynska; Rocio Aranda-Rodriguez; Susan E. Buykx (pp. 467-472).
A capillary electrophoresis (CE) method has been developed and validated for the determination of the distribution of metals in particulate matter after three-stage sequential extraction. Fe(II), Zn(II), Cu(II), Mn(II), and Cd(II) ions were separated using a background electrolyte consisting of 200 mmol L–1 ammonium acetate (pH 5.5), 0.5 mmol L–1 1,10-phenanthroline, 10 mmol L–1 hydroxylamine hydrochloride, and 20% acetone. The method was validated with respect to specificity, linearity, detection limits, precision, and accuracy. Detection limits are at sub-µg L–1 levels (tens of µg g–1 of particulate matter) using pressure injection. The analytical procedure was checked by analyzing a standard reference material, NIST SRM 1648 Urban Particulate Matter
Keywords: Capillary electrophoresis Metals Sequential extraction Airborne particulates
No Title by M. Dernovics; Zs. Stefánka; P. Fodor (pp. 473-480).
Sample preparation methods based on the use of proteolytic and cell wall digesting enzymes for the speciation analysis of selenized mushroom were investigated. The sample (Agaricus bisporus; 160 µg total Se per g sample) was grown on compost supplemented with selenized yeast. Experiments were carried out to elucidate the possible role of the cell wall digesting enzymes – Lysing enzyme and Driselase – in the improvement of extraction efficiency with and without inhibiting proteolysis during cell wall digestion. A 3-step procedure applying Lysing enzyme and pronase gave the highest extraction efficiency (89%); however, the best species recovery was achieved by a one-step proteolytic procedure. All the procedures of selenium speciation were controlled by independent ICP-AES analysis measuring the total amount of selenium.
Keywords: Selenium speciation Se-enriched Agaricus bisporus Sequential enzymatic sample preparation Cell wall digestion
No Title by R. Simon; J. Tietge; B. Michalke; S. Degitz; K.-W. Schramm (pp. 481-485).
Recently a new approach for the analysis of iodinated organic species in human serum has been developed using liquid chromatography–inductively coupled plasma–mass spectrometry (LC–ICP–MS). This method enables quantification of iodide, T4 and T3, as well as reverse T3 (rT3) and the synthetic precursors of TH, monoiodotyrosine (MIT), and diiodotyrosine (DIT) in a single injection. In this work, the LC–ICP–MS approach was used to analyze whole-body homogenates of adult male and female zebrafish (Danio rerio) and tadpoles of the African clawed frog (Xenopus laevis) at two different developmental stages (NF58 and 61) according to Nieuwkoop and Faber. The data demonstrate that the LC–ICP–MS method was successful at measuring I–, MIT, DIT, T4, T3, and rT3 in these two species. Furthermore, the method also detected five additional iodinated compounds which are currently unidentified.
Keywords: Thyroid Zebrafish Iodine species
No Title by Torsten Lindemann; Holger Hintelmann (pp. 486-490).
An HPLC/MS-MS method was developed for the analysis of selenium species. Tandem mass spectrometry (MS-MS) was chosen as a detector to provide structural and molecular information allowing the identification of species, which are not commercially available as standards. A new separation method for selenium species was developed, based on porous graphitic carbon (PGC) as the stationary phase. The applicability of the optimized HPLC/MS-MS system was demonstrated by the analysis of a mixture containing Se-methyl-selenocysteine, selenomethionine, selenocystine, selenoethionine and selenocystamine. All peaks were baseline-resolved and eluted within 16 min. Positive ionization led to higher intensities than negative ionization. Signal suppression tests showed that electrospray ionization (ESI) is a more effective ionization method than atmospheric pressure chemical ionization (APCI) for selenium species in a matrix containing pentafluoropropionic acid, heptafluorobutyric acid or ammonium formate. Comparative experiments with a triple quadrupole mass spectrometer (Quattro LC) and a time-of-flight instrument (Q-Tof-2) showed a 20 fold higher mass resolution of the latter mass spectrometer (m/Δm=5000) and significantly lower intensities for analyte signals as well as background noise compared to the triple quadrupole instrument. MS-MS spectra of the investigated selenium species including characteristic fragmentation patterns are presented.
Keywords: Selenium Speciation Liquid chromatography MS Porous graphitic carbon
No Title by Christian Wolf; Ullrich Rösick; Peter Brätter (pp. 491-494).
Studies to specify various metalloproteins in cell cytosol of tissues using chromatographic separation methods and plasma mass spectrometry for element detection require a careful step by step sample preparation. These steps involve (i) bioptic sample removal from tissue, (ii) extraction and preparation of the tissue supernatant, (iii) the chromatographic separation of the proteins, and finally (iv) the on-line transfer of the column eluate into the plasma mass spectrometer. Each of the analytical steps has to be carefully monitored to avoid undesired changes in the sample composition which could be caused by enzymatic and/or oxidative processes as well as by external element contamination. This presentation introduces a concept to ensure that environmental element contamination does not occur to bias the analytical results.
Keywords: Metalloproteins Biopsy Cytosol extraction Chromatography ICP-MS
No Title by N. Miekeley; S. Mortari; A. Schubach (pp. 495-502).
Results from a study are reported in which patients with leishmaniasis were monitored by whole blood, blood plasma, urine, and hair analysis, before, during, and after intramuscular administration of N-methyl meglumine antimoniate. Quadrupole ICP-MS was used for the detection of antimony and on-line ion chromatography for the separation of its species. After typically 30 consecutive daily injections of 5 mg antimony per kg of body weight, Sb concentrations of up to 250 µg L–1 in whole blood and plasma, and 60 mg of Sb per gram of creatinine in urine, were measured 24 h after drug administration. Antimony in hair samples of these patients showed concentrations of up to 24 µg g–1. Speciation studies of Sb5+ and Sb3+ in drug, urine, and plasma samples were performed by ion chromatography using a Hamilton PRP-100X anion exchange column and EDTA (2 or 20 mM, pH 4.7) as the mobile phases. Repeatability of elution time and peak area measurements for a 0.125 ng spike were <1.2% and <3.5%, respectively. Method detection limits for both species, using a 1:10 diluted urine or plasma sample, were typically 1.6 µg L–1. The procedure was capable of separating the very intense drug peak from its inorganic species, thus permitting the first studies on the bio-transformation of N-methyl meglumine antimoniate to Sb5+ and Sb3+ in the human body.
Keywords: Antimony speciation Ion chromatography ICP-MS Leishmaniasis
No Title by W. Spiewok; J. Ciba; J. Trojanowska (pp. 503-505).
A new method for the determination of organic and pyritic sulfur in hard coal is presented. The method is based on controlled thermal decomposition of coal sample in oxygen-free and oxygen atmospheres.The results for sulfur liberated in an argon atmosphere at temperatures up to 773 K were close to organic sulfur contents (S org), although owing to the definition of 'organic sulfur' the values were not directly comparable. S org contents are calculated from the difference between total sulfur content in coal and contents of this element in the form of sulfides, sulfates and pyrites. Sulfur contents, found in the second stage of analysis, were close to pyritic sulfur contents. The difference between total sulfur content and the sum of sulfur values obtained in stages I and II corresponded to sulfur contents in those samples which were neither decomposed nor oxidized at temperatures up to 1173 K. Although not comparable with such conventional concepts for industrial purposes these data are attractive due to the ease and rapidity of the new method for the control of sulfur streams in industrial processes.
Keywords: Sulfur speciation Coal Thermal decomposition
No Title by Ashok Singh; Amit Panwar; Rupam Singh; Seema Baniwal (pp. 506-510).
A new tetradentate dihydrogen perchlorate macrocyclic ligand (2,4,9,11-tetraphenyl-1,5,8,12-tetraazacyclotetradeca-1,4,8,11-tetraene dihydrogen perchlorate) was prepared and characterised. The macrocycle behaves as a selective chelating ion-exchanger for some metal ions. The polystyrene-based membrane electrode is found to exhibit quite promising selectivity for Cr3+ ions. It can be used to estimate chromium concentrations in the range 3.16×10–6–1.00×10–1 M with a near-Nernstian slope of 17.5 mV per decade of concentration between pH 3.0 to 6.5. The electrode is found to possess a fast response time of 15 s and was used over a period of three months with good reproducibility (s = ± 0.3 mV). The selectivity coefficient values for mono-, di- and trivalent cations indicate excellent selectivity for Cr3+ ions over a large number of other cations. Anions such as Cl- and SO4 2- do not interfere and the electrode also works satisfactorily in a mixed organic-water solution. The sensor has been used as an indicator electrode for the potentiometric titration of Cr3+ with EDTA. The practical utility of the membrane sensor has also been demonstrated in solutions contaminated with detergents (CTAB and SDS). Above all, the membrane sensor has been very successfully used to determine Cr3+ in some foods.
Keywords: Chromium (III)-selective electrode Sensor Macrocycle