NanoSIMS and EPMA analysis of nickel localisation in leaves of the hyperaccumulator plant Alyssum lesbiacum

Certain plants known as ‘metal hyperaccumulators’ can accumulate exceptional concentrations of elements such as zinc, manganese, nickel, cobalt, copper, selenium, cadmium or arsenic in their above ground tissue. In members of the genus Alyssum, nickel concentrations can reach values as high as 3% of leaf dry biomass. These plants must possess very effective mechanisms for the transport, chelation and sequestration of such elements within their tissues to avoid the toxic effects of free metal ions. Evidence from a number of different techniques suggests that nickel is concentrated primarily in the outermost, epidermal tissue of leaves of Alyssum hyperaccumulators, but there is currently no consensus on the principal sites of nickel sequestration. In this study, high resolution secondary ion mass spectrometry (NanoSIMS) analysis has been performed on longitudinal sections of Alyssum lesbiacum leaves. Elemental maps were obtained which revealed the high concentrations of nickel in the peripheral regions of the large unicellular stellate leaf hairs (trichomes) and in the epidermal cell layer. Electron probe microanalysis (EPMA) was used to provide independent confirmation of elemental distribution in the specimens, but the superior spatial resolution and high chemical sensitivity of the NanoSIMS technique provided a more detailed image of elemental distribution in these biological specimens at the cellular level.     

Pre-concentration of ultra trace amounts of copper,zinc, cobalt and nickel in environmental water samples using modified C18 extraction disks and determination by inductively coupled plasma–optical emission spectrometry

A highly sensitive and accurate method for pre-concentration and determination of ultra trace amounts of zinc, copper, cobalt and nickel ions in environmental water samples is proposed. The method is based on the solid phase extraction of these ions on C18-bonded silica extraction disks modified with a novel Schiff base 2,2′-[1,6-hexanediyl bis (nitriloethylidine)]bis-1-naphthol (HDN). The retained ions on the prepared solid phase was eluted with 10 mL 0.01 M nitric acid and measured by inductively coupled plasma–optical emission spectrometry. The extraction efficiency and the influence of the type and least amount of eluent for the stripping of ions from the disks, pH, flow rates of sample solution and eluent, amount of HDN, effect of other ions and breakthrough volume were evaluated. The limits of detection of the method were 0.2, 0.2, 0.8 and 0.6 µg L^?1 for zinc, copper, cobalt and nickel, respectively and an enrichment factor of 100 was obtained. The proposed method was applied for determination of zinc, copper, cobalt and nickel ions in some natural and synthetic water samples with satisfactory results.     

Highly sensitive spectrofluorimetric determination of cysteine by Cu2+-morin complex

p-Toluenesulfonylamide was immobilized on silica gel and on nm-sized silicium dioxide (SiO₂). Their adsorption efficiency toward metal ions was investigated by the batch equilibrium technique. Although silica gel and nm-SiO₂ have the same composition (silicon and oxygen), the difference in their sizes and surface structures results in distinct chemical activity and selectivity. At pH 4, the adsorption capacity of modified silica gel adsorbent was found to be 4.9, 5.0, 33.2, and 12.6 mg g⁻¹ for Cr(III), Cu(II), Pb(II) and Zn(II), respectively. However, the adsorption capacity of nm-SiO₂ adsorbent toward Cr(III) was 26.7 mg g⁻¹ under ultrasonic dispersing. The potential application of p-toluenesulfonylamide-modified silica gel for simultaneous preconcentration of trace chromium, copper, lead and zinc from two standard reference materials and two food samples was performed with satisfactory results. Correspondence: Xijun Chang, Department of Chemistry, Lanzhou University, Lanzhou 730000, P.R. China     

Trace element determination in beauty products by k0-instrumental neutron activation analysis

A recent study on trace elements in beauty products and cosmetics sold on the Asian market has shown the presence of high levels of U, Th and rare earth elements in so called “Hormesis cosmetics.” For the purpose of comparison, some more information about trace elements in European cosmetics would be useful. In this paper the results obtained using k ₀-standardised Instrumental Neutron Activation Analysis (k ₀-INAA) for more than 20 trace elements in 20 different beauty products collected from the European market are presented. We found traces of Ba, As and Sb which is in breach with European legislation. For some of the other elements like Cr and Co further speciation is needed in order to evaluate their presence in beauty products.     

Catalytic activities of polymer‐supported metal complexes in oxidation of phenol and epoxidation of cyclohexene

The metal complexes of N, N′‐bis (o‐hydroxy acetophenone) propylene diamine (HPPn) Schiff base were supported on cross‐linked polystyrene beads. The complexation of iron(III), copper(II), and zinc(II) ions on polymer‐anchored HPPn Schiff base was 83.4, 85.7, and 84.5 wt%, respectively, whereas the complexation of these metal ions on unsupported HPPn Schiff base was 82.3, 84.5, and 83.9 wt%. The iron(III) complexes of HPPn Schiff base were octahedral in geometry, whereas copper(II) and zinc(II) ions complexes were square planar and tetrahedral. Complexation of metal ions increased the thermal stability of HPPn Schiff base. Catalytic activity of metal complexes was tested by studying the oxidation of phenol and epoxidation of cyclohexene in the presence of hydrogen peroxide. The polymer‐supported HPPn Schiff base complexes of iron(III) ions showed 73.0 wt% conversion of phenol and 90.6 wt% conversion of cyclohexene at a molar ratio of 1:1:1 of substrate to catalyst and hydrogen peroxide, but unsupported complexes of iron(III) ions showed 63.8 wt% conversion for phenol and 83.2 wt% conversion for cyclohexene. The product selectivity for catechol (CTL) and epoxy cyclohexane (ECH) was 93.1 and 98.3 wt%, respectively with supported HPPn Schiff base complexes of iron(III) ions but was lower with HPPn Schiff base complexes of copper(II) and zinc(II) ions. Activation energy for the epoxidation of cyclohexene and phenol conversion with unsupported HPPn Schiff base complexes of iron(III) ions was 16.6 kJ mol^?1 and 21.2 kJ mol^?1, respectively, but was lower with supported complexes of iron(III) ions. Copyright © 2007 John Wiley & Sons, Ltd.     

Towards the characterization of metal binding proteins in metal enriched yeast

This paper presents size exclusion chromatography data with on-line coupling to UV and inductively coupled plasma mass spectrometry (ICP-MS) of water soluble metal-binding compounds present in zinc, copper, chromium and iodine enriched yeast nutritional supplements. Molecular weight estimates of the extracted metal-containing compounds are given and are shown to vary substantially from 1.2 kDa to larger than 668 kDa. Seven proteins suspected of containing chromium were identified from one of the chromium-containing fractions. Four of these identified proteins are known to form complexes with other metal ions. The metal chromatographic profiles of zinc, copper and chromium-enriched yeasts were compared to their respective native metal profiles in non-enriched yeast samples. The chromium profiles are shown to be markedly different while those of zinc and copper are qualitatively similar. Only iodide ions or weakly bound, non-aromatic, low molecular weight ( 1.2 kDa) iodine species were observed in the iodine-enriched yeast samples.     

Removal of <Superscript>60</Superscript>Co<Superscript>2+</Superscript> and <Superscript>137</Superscript>Cs<Superscript>+</Superscript> ions from low radioactive solutions using <Emphasis Type="Italic">Azolla caroliniana</Emphasis> willd. water fern

This study concerns the removal of the ¹³⁷Cs⁺ and ⁶⁰Co²⁺ β+γ-radioactive ions in Azolla caroliniana Willd. water fern. The living fern and two different types of biosorbent prepared from Azolla caroliniana were tested to remove the above-mentioned radioactive ions from dilute solutions, in the absence and in the presence of the ionic competition. Effective ¹³⁷Cs⁺ and ⁶⁰Co²⁺ ions removal from low radioactive wastewaters was demonstrated. The time dependent K _d (t) values were calculated from the absorption data. These results indicate that removal process achieved equilibrium in about 120 min and that it involves two steps: rapid and slow absorption; the active process (metabolic bioaccumulation on the living fern) was responsible for above one half of the total removal process. A thin layer radiochromatography study leads to the conclusion that the biochemical components in which ¹³⁷Cs⁺ and ⁶⁰Co²⁺ place themselves are of a polysaccharide and lipoid fractions.     

Effect of Cu(II) on the electrochemically initiated reaction of thiols with<Emphasis Type="Italic"> N</Emphasis>,<Emphasis Type="Italic">N</Emphasis>-diethyl-<Emphasis Type="Italic">p</Emphasis>-phenylenediamine: methodology for the indirect voltammetric determination of Cu(II)

The effect of Cu(II) on the determination of homocysteine via its electrochemically initiated reaction with N,N-diethyl-p-phenylenediamine is examined. The presence of copper inhibited the detection process for homocysteine owing to a complexation reaction occurring. This provided an indirect route for the sensitive and selective determination of Cu(II), which produced a linear response over the range from 2.5 to 500 M and a limit of detection of 2.5 M. The detection pathway was examined in the presence of metallic and inorganic ions, with negligible interference observed.     

Synthesis and properties of new chelating resin with a spacer containing alpha-nitroso-beta-naphthol as the functional group

A new chelating ion-exchange resin with a spacer CH₂-NH-C₆H₄- based on a microreticular chloromethylated styrene-divinylbenzene copolymer containing α-nitroso-β-naphthol as a functional group has been synthesized. The sorption characteristics for manganese(II), iron(III), cobalt(II), nickel(II), copper(II), and zinc(II) have been investigated over the pH range 1.0–7.0. The resin is highly stable in acidic and alkaline medium. Iron(III) and cobalt(II); copper(II) and iron(III) are separated very effectively in a column operation by stepwise elution.     

Synthesis and characterization of new meso -substituted unsymmetrical metalloporphyrins

The synthesis and characterization of new meso-substituted unsymmetrical metalloporphyrins has been described. A new modified Adler method was used for the synthesis of two unsymmetrical porphyrins. Reactions of these unsymmetrical porphyrins with metal acetates afforded the corresponding metalloporphyrins in high yields with excellent purity. These porphyrins and their metal derivatives were characterized by spectroscopic methods. However, the copper complexes were further studied by ESR spectra and zinc complex by fluorescence spectrum.     

Synthesis,spectral characterization,redox and antimicrobial activity of Schiff base transition metal(II) complexes derived from 4-aminoantipyrine and 3-salicylideneacetylacetone

A novel tetradentate N₂O₂ type Schiff base, synthesized from 1-phenyl-2,3-dimethyl-4-aminopyrazol-5-one(4-aminoantipyrine) and 3-salicylidene-acetylacetone, forms stable complexes with transition metal ions such as Cu ^II , Ni ^II , Co ^II and Zn ^II in ethanol. Microanalytical data, magnetic susceptibility, IR, UV-Vis.,¹H-NMR, ESR and Mass spectral techniques were used to confirm the structures. Electronic absorption spectra of the complexes suggest a square-planar geometry around the central metal ion. These complexes show higher conductance values, supporting their electrolytic nature. The monomeric nature of the complexes was confirmed from their magnetic susceptibility values. Cyclic voltammogram of the copper(II) and nickel(II) complexes in DMSO solution at 300 K were recorded and the results are discussed. The X-band ESR spectra of the copper complex were recorded and the molecular orbital coefficient values were calculated from the spectra. The in vitro antimicrobial activities of the investigated compounds were tested against bacteria such as Klebsiella pneumoniae, Staphylococcus aureus, Bacillus subtilis and Escherichia coli and fungi like Aspergillus niger and Rhizoctonia bataicola. Most of the metal chelates show higher antimicrobial activity for the above microorganisms than that of the free ligand.     

Enhancing the production of gamma-linolenic acid in <Emphasis Type="Italic">Hansenula polymorpha</Emphasis> by fed-batch fermentation using response surface methodology

Gamma-linolenic acid (GLA, C18:3Δ^6,9,12) is an n-6 polyunsaturated fatty acid (PUFA) that has been used for the alleviation and treatment of a number of symptoms and diseases. Increasing GLA demand has led to a search for alternative producers and potential strategies for GLA production. Based on the successful performance of Hansenula polymorpha, a methylotrophic yeast, as a “cell factory” for the production of valuable bioproducts, a bioprocess development approach was implemented for GLA production in the recombinant yeast carrying the mutated Δ⁶-desaturase gene of Mucor rouxii. Using a substrate-feeding strategy under glycerol-limited conditions, the physical-chemical variables during the fed-batch fermentation of the recombinant H. polymorpha were optimised for GLA production through response surface methodology using a Box-Behnken design. The medium composition, including yeast extract and trace elements, and dissolved oxygen tension (DOT) were targeted. We found that DOT was the most effective variable for enhancing GLA yield. These results also suggest that the optimum conditions for GLA production are 28 % saturation of DOT, 1 g L⁻¹ of yeast extract and 3.6 mL L⁻¹ of the Pichia trace metals 1 (PTM1).     

Ion/Molekülreaktionen negativ geladener KomplexeSchiffscher Basen mit potentiellen Ligandmolekülen in der Gasphase

Ion/molecule reactions of four coordinateSchiff base complexes under negative ion chemical ionization conditions have been studied. The complex metal ions consisted of cobalt(II), nickel(II) and copper(II).Schiff base ligands with different donor strengths were employed. The gas mixtures used contained 90% methane and 10% of the gases O₂, NO or CO. The spectra showed intense molecular negative ions, formed by secondary electron capture processes. Secondary ions were formed via ion/molecule reactions between the parent molecular negative ion and added gas molecules to giveMLX ^–,X=O₂, NO, CO;L=Schiff base ligand,M=Co(II) or Ni(II). Consistent with former investigations, secondary ion formation was not found for the copper compounds. Influence of the central metal ion as well as the ligand donor strength on the ion/molecule reactions are discussed. From the results obtained a mechanism of the secondary ion formation is suggested.

     

Trace metals in mussel shells and corresponding soft tissue samples: a validation experiment for the use of <Emphasis Type="Italic">Perna perna</Emphasis> shells in pollution monitoring

The uptake of Cr, Mn, Ni, Cu, Zn, Cd and Pb in soft tissue of Perna perna mussels and their shells has been studied in aquarium experiments in which mussels were exposed for 30 or 60 days to seawater spiked with different concentrations of these contaminants (125 and 500 μg L⁻¹). Tissue samples were analyzed after acid digestion by conventional solution nebulization ICP–MS. Laser ablation ICP–MS was used for the quantitative determination of trace elements in different areas of the corresponding shells. With the exception of Mn and Zn, all other elements studied showed a significant concentration enhancements in soft tissue, with the magnitude of this enhancement following the order: Cr > Ni > Cd > Cu > Pb. A corresponding increase in most contaminants, although less pronounced, was also observed in the newly formed growth rings of mussel shells, contributing to the validation of Perna perna mussel shell as a bioindicator of toxic elements.     

Adsorption properties of carbon nanotubes depending on the temperature of their synthesis and subsequent treatment

A correlation between the temperature of the synthesis of carbon nanotubes (CNT) by method of catalytic pyrolysis from ethanol on a nickel catalyst and their ability for the modification of oxidation under various conditions and also their adsorption capacity to a number of metal ions is demonstrated. The study of infrared spectra in correlation with the total acidity of the CNT synthesized and modified under various conditions has shown that the samples synthesized at 400°C possess the maximum ability for modification. This can be explained by the higher deficiency of their structures at low synthesis temperatures. Adsorption isotherms of silver, copper, lead, cadmium, zinc, iron, and magnesium ions under batch and dynamic modes were studied, depending on pH and element concentration in the solution. It was found that CNT synthesized at 400°C and treated with conc. HNO₃ in an autoclave at 110–120°C possess the maximum adsorption capacity of all the studied elements, which exceeds the capacity of active coal, traditionally used for these purposes, by several times. The attained adsorption capacity is 5–10 times higher than that reported in the literature for carbon nanotubes in relation to the same elements. Prospects of using CNT as collectors for the preconcentration of trace impurities in spectroscopic methods of analysis are considered.     

Interference between selenium and some trace elements during polarographic studies and its elimination

When selenite was added into solutions of some ions such as copper, lead, cadmium, zinc, chromium and arsenic their DPP peak decreased. This kind of interference was observed in all acids and in wide range of pH values, causing at least 50% error when both ions (the ion present and selenite) were in similar quantities. It was found that this interference was not taking place at pH 8.5 in the presence of large amounts of selenite. A synthetic sample containing these elements in 10⁻⁵ M in the presence of 50 times selenite has been analyzed at pH 8.5 without any interference. The detection limit in this medium was 3 × 10⁻⁷ M for cadmium and lead, 1 × 10⁻⁶ M for copper and zinc and it was 3 × 10⁻⁷ M for selenite.     

Trace Metal and Persistent Organochlorine Levels in Wood Bison (Bison bison athabascae) from the Mackenzie Bison Sanctuary

Abstract

Tissue samples were collected from ten healthy mature female wood bison (B. bison athabascae) for examination. Livers and kidneys were tested for toxic heavy metals and trace metals considered as essential nutrients for successful reproduction, while fat samples were analyzed for persistent chlorinated hydrocarbons. No elevated levels of toxic heavy metals (arsenic, cadmium, lead, mercury) were found and essential trace elements (copper, manganese, selenium, zinc) were within the acceptable ranges established for healthy cattle. All fat samples tested contained trace levels of α-BHC (mean value, 23 ppb) and lindane (mean value, 3 ppb).     

Colon tissue concentrations of copper, iron, selenium, and zinc in colorectal carcinoma patients

Concentration of four trace elements (copper, zinc, iron, and selenium) was determined in colon tissue from twenty-three patients with colorectal cancer. The tissue samples were dried and dissolved using microwave-assisted digestion technique. The content of trace elements was determined using atomic absorption spectrometry. No significant differences between Zn levels in normal and cancerous tissues were observed. However, the levels of Cu, Fe, and Se were significantly higher in cancerous tissues than in the control samples. The results obtained sing microwave-assisted technique were compared to those obtained via alkaline digestion with tetramethylammonium hydroxide. Both techniques were used for the digestion of certified reference material of pork liver. Very good agreement with the certified values of Cu, Fe, and Zn in the reference material was achieved using alkaline digestion procedure. This technique seems to be an efficient alternative to decomposition of biological samples.     

不同颜色果实唐古特白刺叶中矿物质元素含量的比较

通过采用ICP-MS检测了柴达木盆地3种不同颜色果实唐古特白刺叶中11种矿物质元素. 结果表明不同颜色果实唐古特白刺叶中矿物质元素存在差异. 唐古特白刺叶中常量元素以Na元素最高,其中以紫色果实白刺叶中Na元素和常量元素总量最高,大红果白刺叶最低. 微量元素在白刺叶中以Fe元素含量最高,其中以紫红果白刺叶中Fe元素和必需微量元素总量最高,紫色果含量最低. 另外,有害元素Pb和Cd在3种颜色果实的叶子中含量均较低. 方法简便快速,结果准确可靠,可以为不同颜色果实唐古特白刺叶子的应用提供基础数据.     

Acid-base and complexation properties of <Emphasis Type="Italic">gem</Emphasis>-diphosphonic and <Emphasis Type="Italic">gem</Emphasis>-diphosphinic acids in aqueous solutions and micellar media of surfactants

Acid-base and complexation properties of gem-disubstituted phosphorus acids, viz., methylenediphosphonic, 1-hydroxyethylidene-1,1-diphosphonic, P,P-diphenylmethylene-diphosphinic, and P, P-diphenyl-1-hydroxyethylidene-1, 1-diphosphinic acids, were studied in aqueous solutions and in the presence of biomimetics (micelles of ionic surfactants). The dissociation constants of the acids and stability constants of complexes with magnesium(II) and copper(II) ions were determined in aqueous solutions and microheterogeneous media containing sodium dodecyl sulfate, cetylpyridinium chloride, or cetylpyridinium nitrate (ionic strength 0.1 mol L^–1, temperature 25°C).Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1919–1925, September, 2004.