11 research outputs found
Two-dimensional impurity imaging in deep Antarctic ice cores: snapshots of three climatic periods and implications for high-resolution signal interpretation
Due to its micrometer-scale resolution and inherently micro-destructive nature, laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) is particularly suited to exploring the thin and closely spaced layers in the oldest sections of polar ice cores. Recent adaptions to the LA-ICP-MS instrumentation mean we have faster washout times allowing state-of-the-art 2-D imaging of an ice core. This new method has great potential especially when applied to the localization of impurities on the ice sample, something that is crucial, to avoiding misinterpretation of the ultra-fine-resolution signals. Here we present the first results of the application of LA-ICP-MS elemental imaging to the analysis of selected glacial and interglacial samples from the Talos Dome and EPICA Dome C ice cores from central Antarctica. The localization of impurities from both marine and terrestrial sources is discussed, with special emphasis on observing a connection with the network of grain boundaries and differences between different climatic periods. Scale-dependent i mage analysis shows that the spatial significance of a single line profile along the main core axis increases systematically as the imprint of the grain boundaries weakens. It is demon-strated how instrumental settings can be adapted to suit the purpose of the analysis, i.e., by either employing LA-ICP-MS to study the interplay between impurities and the ice microstructure or to investigate the extremely thin climate proxy signals in deep polar ice
Laser ablation ICP-MS of size-segregated atmospheric particles collected with a MOUDI cascade impactor: a proof of concept
A widely used instrument for collecting size-segregated particles
is the micro-orifice uniform deposit impactor (MOUDI). In this work, a
10-stage MOUDI (cut-point diameter of 10 µm to 56 nm) was used to collect
samples in Ljubljana, Slovenia, and Martinska, Croatia. Filters, collected
with and without rotation, were cut in half and analyzed for nine elements
(As, Cu, Fe, Ni, Mn, Pb, Sb, V, Zn) using laser ablation ICP-MS. Elemental
image maps (created with ImageJ) were converted to concentrations using NIST
SRM 2783. Statistical analysis of the elemental maps indicated that for
submicron particles (stages 6–10), ablating 10 % of the filter (0.5 cm2, 20 min ablation time) was sufficient to give values in good
agreement (±10 %) to analysis of larger parts of the filter and
with good precision (RSE < 1 %). Excellent sensitivity
was also observed (e.g., 20 ± 0.2 pg m−3 V). The novel use of LA-ICP-MS, together with image mapping, provided a fast and sensitive method for
elemental analysis of size-segregated MOUDI filters, particularly for
submicron particles
Influence of copper chloride for the formation of aromatic compounds during polyethylene pyrolysis
International audienceInfrared image furnace ion-attachment mass spectrometry (IIF-IAMS) experiments have been conducted to elucidate the effects of copper(II) chloride on the formation of aromatic compounds during the pyrolysis of polyethylene. Under the time-resolved pyrolysis conditions of IIF-IAMS, the effects of CuCl2 were measured to compare the variation in ratios of alkenes and aromatics during polyethylene thermal degradation when pyrolysis temperature was increased. Thermogravimetry experiments and X-ray powder diffraction analysis conducted under similar conditions to those used for IIF-IAMS enabled us to characterize the oxidation states of copper prevailing during the thermal degradation process of polyethylene in the presence of CuCl2. Reduction of Cu(II) into Cu(I) during the pyrolysis process was characterized. The IIF-IAMS method demonstrates its advantage for on-line detection of reaction products during time-resolved pyrolysis experiments. Cop. 2010 Elsevier B.V. All rights reserved
Ion attachment mass spectrometry combined with infrared image furnace for thermal analysis: Evolved gas analysis studies
International audienceA well-established ion attachment mass spectrometer (IAMS) is combined with an in-house single-atom infrared image furnace (IIF) specifically for thermal analysis studies. Besides the detection of many chemical species at atmospheric pressure, including free radical intermediates, the ion attachment mass spectrometer can also be used for the analysis of products emanating from temperature-programmed pyrolysis. The performance and applicability of the IIF-IAMS is illustrated with poly(tet-rafluoroethylene) (PTFE) samples. The potential of the system for the analysis of oxidative pyrolysis is also considered. Temperature-programmed decomposition of PTFE gave constant slopes of the plots of temperature versus signal intensity in a defined region and provided an apparent activation energy of 28.8 kcal/mol for the PTFE decomposition product (CF2)3. A brief comparison with a conventional pyrolysis gas chromatography/ mass spectrometry system is also given. Cop. 2009 American Chemical Society
3D laser ablation-ICP-mass spectrometry mapping for the study of surface layer phenomena - a case study for weathered glass
In this work, a multi-elemental 3D laser ablation-ICP-mass spectrometry mapping procedure for highresolution
depth information retrieval to investigate surface layer phenomena is presented. The
procedure is based on laser drilling on a virtual grid on the surface, followed by extraction of depth
maps along the z-axis (for each element monitored). Using a burst of 50 laser pulses at 1 Hz on each
point of the grid, a penetration rate of ca. 150 nm per pulse (in glass) was obtained and a lateral
resolution in the order of the laser beam diameter. By ultrafast ICP-MS monitoring of individual ablation
pulses (58 ms for a set of 19 elements) using a laser ablation cell with fast signal washout (less than
0.5 s for whole laser pulse), the corresponding peak areas could be consistently integrated, resulting in
spatial elemental data associated with individual pulses. The usual laser drilling limitations such as pulse
mixing and signal tailing are avoided with this approach. After manipulation of the spatial elemental
datasets and quantification, stacks of 50 2D depth maps (for each element monitored) were produced
which could be visualized as volume images or time-lapse movies. As a proof of concept, this approach
was successfully used to investigate the degradation mechanisms of a medieval, weathered glass artifact
by colocalization analysis of selected cross-sectional 2D elemental images in arbitrary planes of the
volume images. It was shown that degradation must have started as a result of dealkalinization leading
to depletion of alkalis/earth alkalis in glass surface layers and enrichment of network formers (Si and
Al), and subsequent worsening by cracking and formation of corrosion pits and so-called
spatiotemporal Liesegang rings indicative of radial leaching
Selective ablation of biological tissue and single cells on a glass substrate by controlling the laser energy density of nanosecond 193 nm laser radiation
Effects of Solvent Vapor Modifiers for the Separation of Opioid Isomers in Micromachined FAIMS-MS
Benign and ecofriendly depolymerization of polycarbonate wastes into valuable diols using micro- and nano-TiO2 as the solid supports
Lipidomic characterization of the milk fat globule membrane polar lipids
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