The MAT-253 Ultra — a novel high-resolution, multi-collector gas source mass spectrometer

We present the design, performance and representative applications of the MAT 253 Ultra – the first prototype of a new class of high-resolution gas source isotope ratio mass spectrometers

Gas hydrate technology: state of the art and future possibilities for Europe

Interest in natural gas hydrates has been steadily increasing over the last few decades, with the understanding that exploitation of this abundant unconventional source may help meet the ever-increasing energy demand and assist in reduction of CO2 emission (by replacing coal). Unfortunately, conventional technologies for oil and gas exploitation are not fully appropriate for the specific exploitation of gas hydrate. Consequently, the technology chain, from exploration through production to monitoring, needs to be further developed and adapted to the specific properties and conditions associated with gas hydrates, in order to allow for a commercially and environmentally sound extraction of gas from gas hydrate deposits. Various academic groups and companies within the European region have been heavily involved in theoretical and applied research of gas hydrate for more than a decade. To demonstrate this, Fig. 1.1 shows a selection of leading European institutes that are actively involved in gas hydrate research. A significant number of these institutes have been strongly involved in recent worldwide exploitation of gas hydrate, which are shown in Fig. 1.2 and summarized in Table 1.1. Despite the state of knowledge, no field trials have been carried out so far in European waters. MIGRATE (COST action ES1405) aims to pool together expertise of a large number of European research groups and industrial players to advance gas-hydrate related activity with the ultimate goal of preparing the setting for a field production test in European waters. This MIGRATE report presents an overview of current technologies related to gas hydrate exploration (Chapter 2), production (Chapter 3) and monitoring (Chapter 4), with an emphasis on European activity. This requires covering various activities within different disciplines, all of which contribute to the technology development needed for future cost-effective gas production. The report points out future research and work areas (Chapter 5) that would bridge existing knowledge gaps, through multinational collaboration and interdisciplinary approaches

Redetermination of the 21Ne relative abundance of the atmosphere, using a high resolution, multi-collector noble gas mass spectrometer (HELIX-MC Plus)

Analyses of noble gas isotopes by high-resolution, multi-collector mass spectrometry have the potential to revolutionise applications in the cosmo-geo-sciences. The HELIX-MC Plus noble gas mass spectrometer installed at the Australian National University (ANU) is uniquely equipped with three high mass resolution collectors, which permits complete separation of 20Ne from doubly charged interfering 40Ar, 1H19F, 1H218O and partial separation of the 21Ne peak from interfering 20Ne1H. Because of the high mass resolving power, 21Ne can be measured, essentially without interference from 20Ne1H. This capability provides an important opportunity to re-evaluate the relative 21Ne abundance in the atmosphere. Our analyses demonstrate that 20Ne1H contributes approximately 2% to previously determined atmospheric 21Ne relative abundance values. We calculate a new atmospheric 21Ne/20Ne ratio of 0.002905 ± 0.000003 relative to an atmospheric 22Ne/20Ne ratio of 0.102; this new value is distinctly lower than the current IUPAC recommended 21Ne/20Ne value of 0.00298 ± 0.00011. There are several significant implications ensuing from the newly determined value. For example, in the Earth sciences, a critical issue relates to cosmogenic 21Ne surface exposure ages, which involve the calculation of 21Ne concentrations from excess 21Ne, relative to the atmospheric 21Ne/20Ne ratio. For young samples, where cosmogenic 21Ne contents are small and the 21Ne/20Ne ratio is close to the atmospheric value, the revised value could increase cosmogenic 21Ne ages significantly

A high-resolution gas-source isotope ratio mass spectrometer

We describe a new high-resolution, multi-collector gas source mass spectrometer designed for isotopic analysis of volatile and semi-volatile molecules: the Thermo Scientific MAT253-Ultra, a prototype double-focusing isotope ratio mass spectrometer installed in the Caltech laboratories for stable isotope geochemistry. This instrument achieves mass resolving power of up to ∼27,000 (M/ΔM) and can analyze diverse gases and semi-volatile compounds using a conventional dual inlet and/or a carrier gas. It has a multi-collector array comprised of 7 detector positions with adjustable spacing, all of which can register ions through an SEM or Faraday cup and spanning up to a 10^(13) range in signal strength. Abundance sensitivity in the He mass range is as good as 10^(−12), and precision commonly approaches the counting statistics limit down to 0.1‰ (SEM) or 0.01‰ (Faraday) for a range of analytes. This instrument permits resolution of isobaric interferences arising from both contaminants and multiple isotopologues of an analyte that share a cardinal mass, enabling direct isotopic analysis of molecules with complex mass spectra such as hydrocarbons. This ability should enable the measurement of position-specific isotopic compositions, including multiple substitutions, by comparing isotope ratios of molecular ions with those of daughter fragment ions (assuming products of recombination and other source reactions are recognized and corrected for). The combination of high mass resolution with stable multicollection will provide a wide range of potential new tools for isotope geochemistry, including (but not limited to): singly and multiply substituted methane and larger hydrocarbons; position-specific ^(13)C analysis of propane and larger hydrocarbons; precise analysis of ^(17)O/^(16)O and ^(18)O/^(16)O on fragment ions from CO_2 and other molecules; analysis of a variety of N_2O isotopologues (including ^(18)O, ^(17)O, position-specific ^(15)N, and various ‘clumped’ species); and high precision and abundance sensitivity noble gas analyses. These capabilities greatly extend the scope of stable isotope variations that can be utilized for problems in forensics, environmental geochemistry, biochemistry, and Earth and planetary sciences

The MAT-253 Ultra—a novel high-resolution, multi-collector gas source mass spectrometer

We present the design, performance and representative applications of the MAT 253 Ultra – the first prototype of a new class of high-resolution gas source isotope ratio mass spectrometers. The MAT-253 Ultra is a forward geometry double focusing sector mass spectrometer with a Nier-type gas source. Samples are introduced through capilary bleeds from any of 4 automated flexible bellows and/or a carrier-gas port. Ions enter the analyzer through an adjustable entrance slit (5 to 250 m). The analyzer has a 23 cm radius magnet and is similar in scale and design to the Neptune Plus MC-ICPMS. The detector array consists of 1 fixed position and 7 moveable positions on 6 trolleys. An RPQ lens is positioned before the central detector position. Each detector position contains both an SEM and faraday cup detector; each faraday can be registered through any of 10 amplifiers varying in gain from 107 to 1012. Ion beams from m/z 1 to ~300 can be collected, with a ~15 % mass range for simultaneous collection. Useful ion yield is ~1 ion per 1200 molecules for CO2 under standard analytical conditions and using a 250 m entrance slit. The dynamic range in simultaneously measurable ion currents is ~1014. Backgrounds are negligible in the central detector position when the RPQ is in use, permiting quantitative analysis of low intensity ion beams even with high source pressures. Mass resolving power (M/¨M, 5%/95% definition) has been measured up to 26,000 and is routinely as good as ~22-24,000 — sufficient to separate most isobaric interferences among isotopologues of H-C-N-O-S molecular species; in particular, it permits separation of 13C from D isotopologues and both from H adducts in alkanes and related organics. Analyzer system stability is routinely < 2ppm/hour, permitting precise analysis of small features on complex peaks. External precision for isotope ratio measurements of relatively intense ion beams are routinely 10’s of ppm, relative; measurements of weaker ion beam using SEM detectors reach counting statistics limits down to external precisions of ~0.1 ‰. The MAT 253 Ultra enables many previously impossible isotopic analyses of gases and volatile organics and their fragment and adduct ions. Demonstrated examples include: G13C, GD and 13CH3D of methane; G13C of propane and many of its fragments (enabling position-specific 13C determination); direct analysis of G17O G18O, G15N and 15N-18O ‘clumping’ in N2O and its NO fragment; 18O17O and 18O2 in O2; and clumped isotope analysis of CO2 free of contaminant isobaric interferences

Scale-up of Azide Chemistry: A Case Study

We report research and development conducted to enable the safe implementation of a highly enantioselective palladium-catalyzed desymmetrization of a <i>meso</i>–<i>bis</i>-ester using trimethylsilylazide (TMSN₃) as the nucleophile. This work is used as a case example to discuss safe practices when considering the use of azide reagents or intermediates, with a focus on the thermodynamic and quantitative analysis of the hazards associated with hydrazoic acid (HN₃)