Laser Microprobe Research Articles

Laser microprobe for the study of noble gases and nitrogen in single grains: A case study of individual chondrules from the Dhajala meteorite

A laser microprobe capable of analysing nitrogen and noble gases in individual grains with masses less than a milligram is described. It can be used in both continuous wave (CW) mode, useful for stepwise heating of an individual grain, as well as in pulsed mode, useful for ablating material from a small selected area of a sample, for gas extraction. We could achieve low blanks (in ccSTP units) for 4He(4.8 x 10{-12}),22Ne(1.0 x 10{-12}),36Ar(1.0 x10 -13),84Kr(2.9 x 10{-14}),132 Xe(2.6 x 10{-14}), and N (87 pg), using this system. Preliminary data for individual chondrules from the Dhajala meteorite show that noble gases and nitrogen from grains as small as 170 microgram can be analysed using the present laser microprobe setup. The amount of trapped neon in Dhajala chondrules is very small, and nitrogen in the chondrules is isotopically heavier as compared to the bulk meteorite.

Molecular speciation of inorganic mixtures by Fourier transform laser microprobe mass spectrometry

Speciation analysis of as-received solids and micro-objects with the specificity of molecular instead of atomic or functional group information is increasingly needed. Fourier transform laser microprobe mass spectrometry (FT LMMS) is the only method capable of detecting signals referring to the intact analyte (molecular speciation) with the analytical specificity of high mass resolution. Although the methodology has been shown to be unique for identification of constituents in micro-objects and microscopical spots at the surface, its potential for quantitative analysis is often questioned. This paper demonstrates that the step from molecular identification towards semi-quantitative characterisation of local mixtures largely depends on the preparation of suitable reference samples for the calibration of the signal intensities as a function of the local concentration. The experimental methodology elaborated has been verified for mixtures of binary salts and oxysalts including the case of fine speciation, i.e., analytes with the same elements in different oxidation states. The empirical calibration functions allow the local analyte concentration to be determined within 3–10%, which is considered to be adequate for a variety of material science applications at the microscopical level.

Precise dating of low-temperature deformation: Strain-fringe analysis by 40Ar-39Ar laser microprobe

Pyritized graptolites from the Welsh Basin (United Kingdom) slate belt acted as rigid bodies during cleavage formation, and epizonal white micas formed within the resulting. strain shadows, orthogonal to the principal stress orientation. Although the quantities of mica are small, they are a pure synkinematic mineral and have been dated by Ar-40-Ar-39 infrared laser microprobe as a means to dating cleavage. Four samples of strain-fringe mica from different hand samples yielded ages ranging from 394.4 +/- 3.1 to 397.8 +/- 1.8 Ma (2sigma), with a mean age of 396.1 +/- 1.4 Ma (2sigma). By focusing on minerals that are unequivocally synkinematic, this technique provides a novel solution to the problems of isotopically dating slaty cleavage. Previous studies have predominantly relied on dating whole-rock slate samples or separated illite grains by Ar-40-Ar-39 techniques; problems encountered included (1) separating the effects of isotopic contamination by detrital phases, (2) Ar-39 loss during the irradiation of illite mineral separates, and (3) thermally induced Ar-40 loss in nature from fine-grained minerals. By circumventing these problems, this new method provides the first unequivocal and high-precision age data for Acadian deformation in the well-characterized Welsh Basin slate belt. With such precision, the method may afford geologists the opportunity to track tectonic fronts across orogens and assess the rates of accretion processes in areas that are peripheral to sites of continent-continent collision.

Transmission electron microscopy image of wear particles of joint endoprostheses and ultrastructural cell changes

Wear particles from joint endoprostheses vary considerably in size, and may be detectable in tissue only by electron microscopy. Wear debris plays a central role in the non-infectious late loosening of prostheses, and it has been estimated that the submicron particles induce increased liberation of mediators of osteolysis by activated macrophages. From the types of prostheses currently in use, bone cement and polyethylene particles greatly predominate over metallic and ceramic particles. Since it had formerly not been possible to reliably identify wear particles in the transmission electron microscopy, and descriptions of them in the literature varied considerably, we analysed ultrathin sections obtained from periprosthetic tissue containing wear particles previously identified by laser microprobe mass analysis. Using this method, it proved possible to classify almost all the wear particles detected in the electron microscope, to determine their size range and to represent the cellular alterations caused by them.

Capabilities and limitations of Fourier transform laser microprobe mass spectrometry for molecular analysis of solids

Fourier transform laser microprobe mass spectrometry (FT LMMS) has been developed for the molecular analysis of both organic and inorganic components at the surface of microobjects with the ultimate specificity of high-mass resolution. These capabilities are needed in numerous applications of practical material analysis, such as tracing back anomalies in microobjects. The purpose of this paper is to address representative example from industrial trouble shooting, in which organic and inorganic analytes in a single microparticle have been identified unambiguously. This motivates the research to extend the methodology towards quantification. This paper deals with the fundamental aspect of information depth, specifically for inorganic molecular adduct ions. Finally, data will show the quantitative capabilities of FT LMMS. A suitable methodology for the preparation of reference specimens has allowed the empirical calibration of the response as a function of the local concentration to be achieved.

Concentration trends and mixing states of particulate oxalate in Arctic boundary layer in winter/spring

Particulate organic species contribute to the formation of cloud condensation nuclei and may play a role in the formation/growth of condensation nuclei. The field measurements in this paper investigated size distribution and mixing states of particulate oxalate (one of major organic compounds in aerosol particles) in the Arctic boundary layer in during the winter and spring. The variation of particulate oxalate concentration correlated well with nss‐SO42− concentration. This correlation may be due to the direct emissions of oxalate and its precursors of oxalate from anthropogenic sources. The molar ratio of oxalate to nss‐SO42− was found to gradually increase from winter to early spring with the recovery of solar radiation to the Arctic Circle. Individual aerosol particle analysis by means of laser microprobe mass spectrometry showed that most of the oxalate was internally mixed with sulfate in fine particle mode (0.2–2.0 μm).

Oxygen isotope record of the 1997–1998 El Niño in Peruvian sea catfish (Galeichthys peruvianus) otoliths

Sagittal otoliths of the Peruvian sea catfish Galeichthys peruvianus were collected from the north coast of Peru during and after the 1997–1998 El Niño. The otoliths were analyzed via laser microprobe and micromilling techniques for oxygen isotope composition through ontogeny to document their use as an El Niño‐Southern Oscillation (ENSO) proxy. Results were compared to theoretical calculations for the δ18O of otolith aragonite using measured sea surface temperatures (SST) and δ18O values for local seawater assuming equilibrium oxygen isotope fractionation was achieved. All otoliths recorded the 1997–1998 El Niño event as well as seasonal temperature variations. These ENSO events were recorded in otolith aragonite as significant negative excursions in δ18O that reflected the increased temperature of local marine waters. The combined otolith data were used to create a 10‐year SST record, including ENSO events and local seasonal temperature variation, validating the use of otolith δ18O as a temperature proxy.

Histological and scanning electron microscope examination of root canal after preparation with Er:YAG laser microprobe: a preliminary in vitro study.

Until now, there has been no study that demonstrates the effectiveness of Er:YAG laser microprobes to clean and shape the root canal without using any mechanical instrumentation. The study was conducted on 28 single-rooted extracted central incisors teeth with straight roots. Fourteen were mechanically prepared and served as the control group, and 14 were treated by Er:YAG laser only. From every group, half of the teeth were examined histiolgically and half by SEM. The instrument tested was an Er:YAG laser with microprobes 200-400 micro in diameter and 20 mm in length, coupled onto special handpieces, attached to the delivery fiber of an OPUS 20 Er:YAG laser. The Er:YAG laser was applied with the following parameters: wavelength 2.94 microm; pulse duration 400 msec; repetition rate 10 Hz; energy per pulse 140 mJ for the 400 micro microprobe and 90 mJ for the 200-micro microprobe. For the control group, histologically, large amounts of residual pulp tissue were found in the root canal cavity, and open tubules were seen in all the specimens; SEM examination showed very uniform root canal, from apical to cervical portion, high number of open tubules, and different levels of canal debridment. For the study group, histologically, no residual pulp tissue was found in the root canal cavity and open tubules were seen in all the specimens; SEM examination showed the root canal free of debris, removed smear layer, open dentinal tubules, and different levels of enlargement. Our results show that the Er:YAG laser special microprobes are effective in shaping, cleaning, and enlarging straight root canals faster and more efficiently then traditional methods.

Metal and composite nanocluster precipitate formation in silicon dioxide implanted with Sb+ ions

Amorphous thin SiO2 layers of different thickness on a Si(111) substrate were implanted with 12 keV 121Sb+ ions at fluences between 1×1015 cm−2 and 5×1015 cm−2, followed by thermal annealing. Formation of nanocrystal precipitates was established by high-resolution electron microscopy. The size and the distribution of the nanocrystals formed around the initial depth of implantation were studied in the as-implanted samples. The crystalline structure of these nanocrystals was also explored and the presence of antimony oxide Sb2O3 in the form of valentinite was proven. After the annealing step, the implanted material was observed to spread into a wider band and even to split into two discrete bands. The presence of antimony oxide in the intermediate phase (as-implanted layer of Sb) was confirmed using Fourier transform laser microprobe mass spectrometry. No definite signals of Sb2O3 could be detected in the annealed samples.

Intra‐annual variation in the stable oxygen and carbon and trace element composition of sclerosponges

This paper presents data to support the presence of (1) intra‐annual signals in the chemical composition (δ18O and Sr/Ca) of the skeletons of sclerosponges from the Bahamas and (2) variable rates of skeletal accretion. These conclusions are based on data obtained by using a microsampling method for the stable oxygen and carbon isotopes in which material was extracted at a resolution of one sample every 34 μm and a laser microprobe which obtained trace element data every 20 μm (Sr, Mg, and Pb). An age model was established using a combination of changes in the concentration of Pb, the change in the δ13C of the skeleton of the sclerosponges, and U/Th isotopic measurements. These methods yield a mean growth rate of 220 μm/yr but suggest that the growth rate in this particular sclerosponge was not constant. The calculated growth rate is within error identical to that determined by U/Th methods. The variable growth rate was confirmed through spectral analysis of the δ18O and Sr/Ca data that showed peaks corresponding to the annual cycle in these parameters as well as peaks corresponding to growth rates of approximately 128, 212, 270, and 400 μm/yr. The presence of these additional frequencies suggests a growth rate between approximately 100 and 300 μm/yr. These conclusions were supported by modeling of oxygen isotopic data measured on a scleractinian coral as well as model isotope data generated on synthetic time series. These findings have important implications for the use of sclerosponges as proxies of paleoclimate because they emphasize the need for a precise yearly chronology in order that proxy data can be compared with climatic variables.

The resonance laser ablation Fourier-transform ion cyclotron resonance mass spectrometry (RLA-FTICRMS) a new coupling for material science

The development of a new device, which associated resonant ionization and Fourier-transform ion cyclotron resonance mass spectrometry by coupling a tunable laser with the laser microprobe Fourier-transform ion cyclotron resonance mass spectrometry (FTICRMS) developed at the University of Metz, allowed us to carry out the first resonance laser ablation Fourier-transform ion cyclotron resonance mass spectrometry (RLA-FTICRMS) experiments. RLA-FTICRM ensures, due to the involved processes, an increase in the selectivity and sensitivity of the ionization and a high mass resolution by the use of a FTICR mass spectrometer. These potentialities lead us to consider this new technique as a tool of choice for the analysis of inorganic traces by resonant laser ablation/ionization mass spectrometry (RLA-MS). The first experiments reported in this study ensures a 2–7 benefit in selectivity, according to the studied matrix and a limit of detection lower than 1 ppm for chromium. Finally, the influence of the power density on the involved processes was highlighted and allowed us to determine that the resonant processes are most effective for power density lower than 5×10 8 W/cm 2.

The fungal sheath of ectomycorrhizal pine roots: an apoplastic barrier for the entry of calcium, magnesium, and potassium into the root cortex?

The apoplastic permeability of the fungal sheath of two different ectomycorrhizal associations of Pinus sylvestris L. was analysed by laser microprobe mass analysis (LAMMA) and energy-dispersive X-ray spectroscopy (EDXS) after stable isotope labelling with 25Mg, 41K and 44Ca. Entry of 25Mg and 44Ca into the outer cortical apoplast of non-mycorrhizal roots was detected after 4 min of labelling. After a longer exposure time the endodermis with its Casparian band acted as an efficient apoplastic diffusion barrier for the radial movement of 25Mg and 44Ca into the stele. A fraction of approximately one-third of the apoplastic cations of the root cortex could not be exchanged against the external label even after longer exposure times. The ectomycorrhizal sheath of the two fungal species used, Pisolithus tinctorius (Pers.) Coker & Couch and Suillus bovinus (L. ex Fr.) Kuntze, does not completely inhibit the apoplastic movement of ions into the mycorrhizal root cortex, but retarded the penetration of isotopes into the cortical apoplast. In roots inoculated with S. bovinus, a clear labelling of the cortical apoplast could first be detected after 24 h of exposure to the stable isotope solution. At this time the labelling of the cortical apoplast in these mycorrhizal roots was higher than those of non-mycorrhizal roots and, with EDXS, changes in the element composition of the apoplast were detected. The results indicated that possibly hydrophobins localized in the fungal cell wall might be involved in the increased hydrophobicity of mycorrhizal roots and the lower permeability of the ectomycorrhizal sheath.

Collision Event during 177–135 Ma on the Eastern Margin of the Qinghai‐Tibet Plateau: Evidence from 40Ar/39Ar Dating for Basalts on the Western Margin of the Yangtze Platform

Abstract Geochronology of continental flood basalts sampled from the Emei large igneous province (LIP) on the western margin of the Yangtze platform was investigated by the laser microprobe 40Ar/39Ar dating technique. These basalts yield a fairly wide range of 40Ar/39Ar ages, varying from 259 to 135 Ma. One basalt sample, at least altered, recorded the oldest 40Ar/39Ar age of about 259 Ma, corresponding to a peak eruption age of the Emei LIP continental flood basalts. Most of the samples yield much younger ages from 135 to 177 Ma, which are consistent with the K‐Ar ages for the same samples (122.8–172.1 Ma). The dating data suggest that these Permian basalts had been widely affected by the regional tectonothermal event at 177–135 Ma. The event was probably caused by the convergence and collision among the Laurasia, Yangtze and Qiangtang‐Qamdo continental blocks on the eastern margin of the Qinghai‐Tibet plateau after the late Triassic. The age of the event reflects the timing of the peak collisional orogeny.

Structural Change at the Interface of 4'-Nitrobenzylidene-3-Acetamino-4-Methoxyaniline Heteroepitaxial Layer Grown on 4'-Nitrobenzylidene-3-Ethylcarbonylamino-4-Methoxyaniline by Microprobe Laser Raman Spectroscopy

Structural change of a 4'-nitrobenzylidene-3-acetamino-4-methoxyaniline (MNBA)/4'-nitrobenzylidene-3-ethylcarbonylamino-4-methoxyaniline (MNBA-Et) heterostructure has been investigated by microprobe laser Raman spectroscopy. It has been proved that the position shift of the Raman spectrum around 1580 cm-1 originating from the phenyl ring indicates that the surface condition of the MNBA-Et has a large influence on the relaxation process of lattice mismatching between MNBA and MNBA-Et. It is considered that MNBA-Et homoepitaxial layer is an important layer for achieving a longer relaxation of MNBA heteroepitaxial layer.

Observation of Sb 2 O 3 Nanocrystals in SiO 2 after Sb Ion Implantation

Antimony nanocrystals were formed in thin SiO2 films using low-energy ion implantation of Sb followed by annealing. Using Fourier transform laser microprobe mass spectrometry (FT LMMS), we observed for the first time the presence of antimony oxide in the intermediate phase (as-implanted layer of Sb) by means of signals referring to the intact Sb2O3 molecules. Only SbO+ fragments, but no adduct ions of Sb2O3 could be detected in annealed samples. The size and the distribution of the nanocrystals formed around the initial depth of implantation were studied in the as-implanted samples by high-resolution electron microscopy (HREM). The crystalline structure of these nanocrystals was also studied and the presence of antimony trioxide Sb2O3 in the form of valentinite was proven. After the annealing step, the implanted material had spread into a wider band. The method introduced here, based on combining TEM (transmission electron microscopy) and FT LMMS results, offers the possibility of studying the evolution of the phases in Sb nanocrystal formation.

Glandular hairs of Sigesbeckia jorullensis Kunth (Asteraceae): morphology, histochemistry and composition of essential oil.

Long-stalked glandular hairs of outer and inner involucral bracts of Sigesbeckia jorullensis, which are important for epizoic fruit propagation, were investigated using light and scanning electron microscopy. The essential oil secreted by the hairs was analysed by chromatographic methods including gas chromatography/mass spectrometry and with a laser microprobe mass analyser. The glandular hairs consisted of a large multicellular stalk and a multicellular secreting head. The apical layer of glandular head cells was characterized by leucoplasts and calcium oxalate crystals. Below the apical cells there were up to six layers of cells containing many chloroplasts around the nucleus and surrounded by vacuoles filled with flavonoids and tannins. The essential oil originating in the head cells was secreted into the subcuticular space and may be liberated by rupture of the cuticle. It was mainly composed of sesqui- and diterpenes, with the sesquiterpene hydrocarbon germacrene-D as the main component. Monoterpenes, n-alkanes and their derivatives as well as flavonoid aglycones were also detected. The stickiness of the essential oil is probably associated with the high content of oxygenated sesqui- and diterpenes. In addition to long-stalked trichomes, small biseriate trichomes occurred, secreting small quantities of essential oil into a subcuticular space.

Localization of metals in cells of saprophagous soil arthropods (Isopoda, Diplopoda, Collembola).

This review summarizes results on the intracellular distribution of metals in cells of woodlice (Isopoda), millipedes (Diplopoda), and springtails (Collembola), which are three major groups of saprophagous arthropods contributing to the turnover of soil organic matter. Although the impact of metals and also metal pollution has inevitably been shown at levels of higher biological organization than subcellular mechanisms in these animal groups, the aim of this review is to focus exclusively on storage sites and aspects of intracellular metal metabolism. Thus, methodologically, results obtained by microscopical techniques such as histochemistry, X-ray microanalysis, energy filter transmission electron microscopy, or laser microprobe mass spectrometry were given preference. Results from atomic absorption spectrophotometry of cellular fractions were kept to a minimum. In all three taxa, the main intracellular metal storage sites are various types of "granules" which are widely distributed throughout cell types associated with the digestive system.

Mass spectrometry study of nanomaterial precursors: comparison between thermal pyrolysis and laser ablation ionization modes

Zinc and cadmium thiophenolate compounds [(CH 3) 4N] 2M 4[SC 6H 5] 10; [(CH 3) 4N] 4M 10S 4[SC 6H 5] 16 and M 10S 4[SC 6H 5] 12 (with M=Zn or Cd) were studied by thermal pyrolysis/GC/MS and by laser microprobe (Nd/YAG third harmonic 355 nm) coupled with Fourier transform ion cyclotron resonance mass spectrometry. In each case, characteristic fragments can be used to identify the nanomaterial precursor analyzed, depending on the size and metallic composition. The ion signals are identified by m/ z values and compared to calculated isotopic distributions. The results presented herein strengthen the utility of pyrolysis processes connected with mass spectrometry techniques in the characterization of thiolate-capped metal chalcogenide clusters.

Fingerprinting polyorogenic detritus using the 40Ar/39Ar ultraviolet laser microprobe

Research Article| June 01, 2002 Fingerprinting polyorogenic detritus using the 40Ar/39Ar ultraviolet laser microprobe Sarah C. Sherlock; Sarah C. Sherlock 1Department of Earth Sciences, The Open University, Walton Hall, Milton Keynes MK7 6AA, UK Search for other works by this author on: GSW Google Scholar Kevin A. Jones; Kevin A. Jones 2Geology (BMS), Oxford Brookes University, Headington, Oxford OX3 0BP, UK Search for other works by this author on: GSW Google Scholar Simon P. Kelley Simon P. Kelley 3Department of Earth Sciences, The Open University, Walton Hall, Milton Keynes MK7 6AA, UK Search for other works by this author on: GSW Google Scholar Author and Article Information Sarah C. Sherlock 1Department of Earth Sciences, The Open University, Walton Hall, Milton Keynes MK7 6AA, UK Kevin A. Jones 2Geology (BMS), Oxford Brookes University, Headington, Oxford OX3 0BP, UK Simon P. Kelley 3Department of Earth Sciences, The Open University, Walton Hall, Milton Keynes MK7 6AA, UK Publisher: Geological Society of America Received: 30 Oct 2001 Revision Received: 31 Jan 2002 Accepted: 13 Feb 2002 First Online: 02 Jun 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (2002) 30 (6): 515–518. https://doi.org/10.1130/0091-7613(2002)030<0515:FPDUTA>2.0.CO;2 Article history Received: 30 Oct 2001 Revision Received: 31 Jan 2002 Accepted: 13 Feb 2002 First Online: 02 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Sarah C. Sherlock, Kevin A. Jones, Simon P. Kelley; Fingerprinting polyorogenic detritus using the 40Ar/39Ar ultraviolet laser microprobe. Geology 2002;; 30 (6): 515–518. doi: https://doi.org/10.1130/0091-7613(2002)030<0515:FPDUTA>2.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract Detrital white micas from a sandstone unit within the Old Red Sandstone of southwest Wales have been analyzed with 40Ar/39Ar ultraviolet and infrared laser microprobes (UVLAMP, IRLAMP) to determine their source region. Single-grain fusion ages determined by the IRLAMP range from 430 ± 2 to 587 ± 3 Ma, and intragrain ages determined by the high-spatial-resolution UVLAMP range from 435 ± 9 to 875 ± 5 Ma. The UVLAMP technique reveals strong 40Ar/39Ar age zonation preserved within all the analyzed grains, and thus the single-grain fusion 40Ar/39Ar ages determined by the IRLAMP are artifacts of this zonation and represent an average of the old and young ages within each grain. Comparing the observed UVLAMP ages with calculated diffusion profiles for various thermal histories suggests that these detrital micas had a complex polymetamorphic evolution. A thermal event ca. 870 Ma was partly reset by a subsequent thermal event ca. 470 Ma, which is also complicated by Ar loss via a mechanism other than volume diffusion. Such detail as this from detritus allows for a fairly narrowed interpretation of the possible source region, which in this case is the Laurentian Northern and Central Highlands of Scotland. The UVLAMP technique also offers valuable insight into the complexities of dating detrital mineral grains and into the potential for misidentifying source regions and constructing misleading sedimentary systems, because the ages produced by 40Ar/39Ar dating techniques using either bulk-mineral separates or single-grain fusion will result in average ages from strongly zoned mineral grains. These data represent the first application of the 40Ar/39Ar UVLAMP to detrital minerals and provide insight into the potential for such a technique to investigate the thermal histories of now-eroded mountain belts. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

Spark-Anodic Oxide Coatings Formed on Al and Ti Alloys in Tungstate-Containing Phosphate-Vanadate Baths

Oxide coatings superficially, enriched with P, V, or W, were formed on aluminum and titanium alloys by their spark-anodizing in aqueous baths containing NaH2PO4 · 2Н2О (45.9 g/l), NaVO3 · 2Н2О (15 g/l), and different concentrations of Na2WO4 · 2Н2О. The coatings' composition was investigated with laser mass spectrometry and microprobe analysis, while the state of phosphate groups in solution, was with NMR spectroscopy using 31P nuclei. The elemental composition of the coatings presumably depends on the composition and concentration of vanadate-tungstate-phosphates and vanadate-tungstates in solution.