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Arbuscular mycorrhizal fungi alter Hg root uptake and ligand environment as studied by X-ray absorption fine structure
Alojz Kodre, Iztok Arčon, Marta Debeljak, Mateja Potisek, Matevž Likar, Katarina Vogel-Mikuš, 2017, izvirni znanstveni članek

Opis: Mercury (Hg) – plant – fungal interactions are only poorly studied. Hg speciation and ligand environment in maize roots inoculated with arbuscular mycorrhizal (AM) fungi were investigated in order to better understand the role of AM in Hg soil to root transfer. The maize plants were grown in Hg polluted substrate (50 mg g1 as dissolved HgCl2) and inoculated with AM fungi originating from: a) highly Hg polluted environment of a former Hg smelting site in Idrija, Slovenia, (Glomus sp. – sample AmI), and b) non-polluted environment (commercial AM inoculum Symbivit1 – sample AmC). Hg speciation and ligand environment in maize roots was studied by Hg-L3 XANES and EXAFS with emphasis on XAS methodology – modelling and fitting the XAFS spectra to extract in a reliable way as much information on Hg coordination as possible. The AmI plants developed more arbuscules and less vesicles than the AmC plants, and also accumulated more Hg in the roots. A clear difference in Hg coordination between the AM (AmC & AmI) and the control (ConC & ConI) plants is recognized in Hg L3-edge EXAFS analysis: in the ConC & ConI maize roots 73–80% of Hg is attached between two sulphur atoms at the distance of 2.34 Å. The remaining ligand is nitrogen at 2.04 Å. In AmI & AmC roots another Hg-S attachment encompassing four thiol groups at the S-distance of 2.50 Å are identified, accounting for 21–26%. AM fungi can modify Hg ligand environment in plant roots, thus playing an important role in biogeochemical cycling of Hg in terrestrial ecosystems.
Najdeno v: ključnih besedah
Ključne besede: EXAFS XANES Arbuscular mycorrhiza Phytoremediation Toxicity Hg coordination Ligand environment
Objavljeno: 27.09.2016; Ogledov: 764; Prenosov: 0
.pdf Polno besedilo (1,82 MB)

Heavy metal analysis with in-situ prepared copper film electrode as a tool for environmental monitoring
Nana Ivana Hrastnik, 2017, magistrsko delo

Opis: Monitoring and measuring heavy metals in the environment is of great importance and requires sensitive and reliable analytical techniques capable of detecting trace level concentrations. Nowadays, measurements of heavy metals are usually performed using sophisticated and expensive instrumental techniques, such as atomic absorption spectroscopy (AAS), atomic fluorescence spectroscopy (AFS), inductively coupled plasma mass spectrometry (ICP-MS), inductively coupled plasma optical emission spectroscopy (ICP-OES) etc. In this aspect, advanced electroanalytical (stripping) techniques represent a favourable alternative, facilitating sensitive and selective measurements of various analytes using relatively simple, portable and non-expensive instrumentation. This work is an investigation of novel copper-based electrodes for measuring trace levels of selected heavy metal ions, i.e. mercury(II), lead(II), tin(IV) and nickel(II). The methods of choice were anodic stripping voltammetry (ASV) in combination with the in-situ prepared copper film electrode (CuFE) for measuring low concentrations of mercury(II) and lead(II) (simultaneously) and tin(IV) in the test solutions and adsorptive cathodic stripping voltammetry (AdCSV) for determination of nickel(II). Metal-film electrodes are regularly employed in electrochemical stripping analysis due to their simple fabrication and surface regeneration. The newly developed CuFE appears to be a cheaper alternative to gold-based electrodes with several attractive electroanalytical characteristics, i.e. with low limits of detection (LOD), good repeatability and favourable linear response.
Najdeno v: ključnih besedah
Ključne besede: Copper film electrode, anodic stripping voltammetry, adsorptive cathodic stripping voltammetry, heavy metals, environment.
Objavljeno: 12.09.2017; Ogledov: 81; Prenosov: 6
.pdf Polno besedilo (1,78 MB)

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