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Berlin Brandenburg

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  • 1
    In: Journal of Environmental Monitoring, 2011, Vol.13(5), pp.1204-1211
    Description: The pore water transport of antimony and titanium, applied as nanoparticles (NPs), was studied by spiking stable suspensions of two different nanomaterials on the surface of an undisturbed floodplain soil. For preparation of stable dispersions, two different strategies were followed. (i) Comparable to those used in industrial applications: titanium dioxide nanoparticles, with an average diameter of 99 nm, were prepared by high-energy ball milling in water, whereas for (ii) antimony trioxide (Sb 2 O 3 ; average diameter 121 nm) a dispersing agent (sodium salt of poly[(naphthaleneformaldehyde)sulfonate] (pNFS) in water) was used. The upper 17 cm of a floodplain soil (river Rhine, Germany) was sampled using the minimally invasive sediment or fauna incubation experiment (SOFIE® two compartment cell; 3 l volume each), which preserved the pore system of the soil. The cells were equipped with 450 and 100 nm filter probes at different depths providing a non-invasive sampling of the pore water. The pore water was sampled at different times ( T = 0, 24, 48, 96 and 196 h) and analysed by inductively coupled plasma quadrupole mass spectrometry (ICP-QMS). Sb and Ti were transported via the pore water of the floodplain soil to a depth of 14 cm, corresponding to the maximum cell depth. The highest Sb concentration in the pore water was detected after 24 h at a depth of 5.5–8 cm. Although the spiked concentration was higher for Ti than for Sb, the total Ti concentration in the pore water of the spiked cell was lower. This indicates a stronger agglomeration of TiO 2 NPs or a more intensive interaction of Ti with the solid matrix and a faster transport of Sb towards deeper soil layers. The results show that metal(loid)s from metal oxide NPs are transported in the soil pore water and, hence, have the potential to act as the source of contamination of deeper soil layers after soil surface contamination.
    Keywords: Environmental Monitoring ; Flood Plains ; Mass Spectrometry ; Nanoparticles ; Sodium ; Soil ; Soil Depth ; Metals ; Pore Water ; Titanium Dioxide ; Antimony ; Flood Plains ; Nanotechnology ; Germany ; Europe, Rhine R. ; Freshwater Pollution ; Environment ; Renewable Resources-Terrestrial ; Instruments (551.508);
    ISSN: 1464-0325
    E-ISSN: 1464-0333
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  • 2
    In: Journal of Analytical Atomic Spectrometry, 2011, Vol.26(2), pp.450-455
    Description: The demand to quantify the elemental composition of very small sample amounts and/or of samples which form artefacts during conventional sample preparations is increasing. Example applications are the quantification of engineered metal(loid) based nanomaterials in environmental samples, e.g. (i) the direct analyses of engineered nanoparticle (ENP) suspensions showing broad particle size distributions which are not suitable to be applied via the spray chamber in ICP-MS analyses, (ii) measurements of single invertebrates and tissue of selected organs which were exposed to ENPs, and (iii) whole plants or plant parts e.g. from Lemna sp. The use of imaging based high resolution methods like atomic force microscopy or environmental scanning electron microscopy creates the need to quantify the elemental composition of the visualised objects as directly and exactly as possible, at very low limits of detection. With this study the authors present a method/concept for the multi-element quantification of analytes from ENPs in complex matrices with different degrees of complexity by graphite furnace electrothermal vaporisation coupled to inductively coupled plasma quadrupole mass spectrometry equipped with collision/reaction cell (GF-ETV-ICP-QMS).
    Keywords: Demand ; Imaging ; Invertebrates ; Mathematical Analysis ; Matrices ; Matrix Methods ; Nanomaterials ; Nanoparticles ; Instruments and Measurements (So);
    ISSN: 0267-9477
    E-ISSN: 1364-5544
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  • 3
    In: Environmental Science: Nano, 2018, Vol.5(1), pp.191-202
    Description: Sunscreens are an important source of TiO 2 nanoparticles in surface waters. The fate and toxicity of these particles have not been fully addressed due to the gap between model nanoparticles usually used in studies and the more complex particles found in commercial products. Therefore, mild extraction methods for TiO 2 nanoparticles from sunscreens were evaluated for providing more realistic nanoparticle samples for future studies. We propose two methods based on ultrafiltration and ultracentrifugation, respectively, for extracting TiO 2 nanoparticles from sunscreens using a surfactant solution as the solvent. These methods were tested on eleven commercial sunscreens with differing compositions. The ultracentrifugation variant allows extracting 250 mg from approximately 5 g of sunscreen in one day. Recoveries for ultrafiltration and ultracentrifugation were 5296% and 7898%, respectively. Purification efficiency was determined for the ultracentrifugation variant by determining the avobenzone concentration in sunscreen extracts using UV-spectrometry and was high for all tested sunscreens. Transmission electron microscopy and dynamic light scattering revealed a high diversity in particle shape, although size parameters were comparable (average hydrodynamic diameter: 1934 nm). Isoelectric points were below 4.6 for all sunscreen extracts. Time-of-flight secondary ion mass spectrometry revealed that probably all TiO 2 particles were coated; most of them with PDMS, some others with Al- and Si-based materials. Comparison of images of particles inside the sunscreens using cryogenic transmission electron microscopy and of extracted particles showed that while the shape of the primary nanoparticles was not affected by the extraction, they were agglomerated inside the sunscreens. These agglomerates could be completely disrupted using ultrasonication. Therefore, the particles extracted in the present study can be considered as more environmentally relevant in terms of size, shape, surface charge and coating than model TiO 2 nanoparticles.
    Keywords: Mass Spectrometry ; Polydimethyl Siloxanes ; Commercialization ; Light Scattering ; Toxicity ; Nanoparticles ; Light Scattering ; Particle Shape ; Nanoparticles ; Mass Spectrometry ; Toxicity ; Transmission Electron Microscopy ; Silicone Resins ; Surface Charge ; Scientific Imaging ; Nanoparticles ; Ultrafiltration ; Toxicity ; Particle Shape ; Sunscreens ; Surface Water ; Sunscreen ; Secondary Ion Mass Spectrometry ; Transmission Electron Microscopy ; Ultracentrifugation ; Agglomerates ; Purification ; Ultrafiltration ; Titanium Dioxide ; Titanium Dioxide ; Isoelectric Points ; Surface Charge ; Mass Spectroscopy ; Transmission Electron Microscopy ; Image Transmission ; Particulates ; Biocompatibility ; Surgical Implants ; Electron Microscopy ; Ultrafiltration ; Charge Simulation ; Aluminum ; Sun Screens ; Titanium Dioxide ; Photon Correlation Spectroscopy ; Toxicity ; Electron Microscopy ; Methodology ; Ultraviolet Radiation ; Hydrodynamics ; Nanoparticles ; Shape ; Mass Spectroscopy ; Light Scattering ; Transmission ; Water Purification;
    ISSN: 2051-8153
    E-ISSN: 2051-8161
    Source: Royal Society of Chemistry
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  • 4
    In: Environmental Science: Nano, 2016, Vol.3(2), pp.418-433
    Description: Understanding of the interplay of generally known colloidal transformations under conditions of test media (TM) used during cultivation of organisms and biological effect (=ecotoxicological) studies is still limited, although this knowledge is required for an adequate interpretation of test outcomes and for a comparison among different studies. In this context, we investigated the aggregation and dissolution dynamics of citrate-stabilized silver nanoparticles (Ag NPs) by varying the composition of three TM (ASTM, SAM-5S, and R2A, used during bioassays with Daphnia magna , Gammarus fossarum , and bacterial biofilms, respectively) in the presence and absence of two types of natural organic matter (NOM), namely, Suwanee River humic acid (SRHA) and seaweed extract (SW). Each original test medium induced reaction-limited aggregation of Ag NPs, and aggregation increased from R2A to SAM-5S and ASTM. In addition to the differences in aggregation dynamics, the concentration and speciation of Ag( i ) differed between the three TM, whereby SAM-5S and ASTM are comparable with respect to the nature of the aggregation process but clearly differ from the R2A medium. Furthermore, Cl , mainly present in SAM-5S, induced NP stabilization. The release of silver ions from Ag NPs was controlled by the presence of NOM and organic constituents of TM and by interactions with Cl and Br . The degree of aggregation, formation of interparticle cationNOM bridges or stabilization was larger for Ca 2+ than for Mg 2+ due to the stronger ability of Ca 2+ to interact with citrate or NOM compared to Mg 2+ . These observations and the dependence of aggregation rates on the particle concentration renders the interpretation of doseresponse relationships challenging, but they may open perspectives for targeted ecotoxicological testing by modifications of TM composition.
    Keywords: Bacteria ; Media ; Stabilization ; Concentration (Composition) ; Silver ; Nanoparticles ; Dynamics ; Agglomeration ; Chemical and Electrochemical Properties (MD) ; Chemical and Electrochemical Properties (Ep) ; Chemical and Electrochemical Properties (Ed) ; Chemical and Electrochemical Properties (EC);
    ISSN: 2051-8153
    E-ISSN: 2051-8161
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