Showing: Mass Spectrometry

AGILENT 7500cs ICP-mass spectrometer (ICP-MS)

Image of AGILENT 7500cs ICP-mass spectrometer (ICP-MS)Image of AGILENT 7500cs ICP-mass spectrometer (ICP-MS)

Instrument

Quadrupole-based ICP-mass spectrometer

Technical Data/Features

  • octopole reaction cell (ORS) for removal of spectral interferences (c mode)
  • second vacuum pump for enhanced detection power (s mode)
  • Pt interface

Inductively coupled plasma – mass spectrometry (ICP-MS) is a powerful method for the determination of the (trace) element chemical composition of a sample. A mass spectrometer (MS) separates ionized elements and isotopes according to their mass-to-charge ratio (m/z) for subsequent quantification. Samples are introduced as liquids after pneumatic nebulization, or as dry aerosols after desolvation or laser ablation. The inductively coupled argon plasma (ICP) with temperatures of ∼6000 K is the ion source of the MS. Ions formed in the ICP are extracted through the interface into the high vacuum part of the MS and focused towards the quadrupole mass filter by ion optics (electrostatic lenses and octopole). The octopole reaction system (ORS) accomplishes collisions or reactions of interfering molecular ions with a gas phase (typically He, H2) for a reduction of spectral interferences from polyatomic ions. The subsequent quadrupole acts like a band-pass filter allowing transmission of ions with a given m/z ratio at a time. The mass resolution is 1- 0.5 mass units. A quadrupole allows very rapid scanning over the entire mass range (6-238 m/z) within <200ms. The detector (secondary electron multiplier, SEM) converts ion counts into electrical pulses (pulse counting mode) and/ or an electrical current (analog mode). The dynamic range of the SEM is 109 CPS. This signal (in counts per second, CPS) is recorded for each analysed isotope and transmitted to computer software for conversion into quantitative results (e.g., μg/L) after calibration with pre-defined calibration standards. ICP-MS is a very rapid and extremely sensitive multi-element analytical method. Almost all elements of the PSE from Li to U (not: H, C, O, N, noble gases) can be analysed with typical limits of detection in the ng/L (ppt) range and below. However, ICP-MS is prone to mass spectral interferences that have to be identified and corrected for. Alternative sample introduction systems (see “Accessories”) allow the analysis of ultra-small sample volumes <100μL (dedicated PFA micro-nebulizers), the reduction of interferences from oxide polyatomic ions (desolvating nebulizer), and the on-line chromatographic separation of sample matrix components (SeaFAST system) as in e.g., seawater.

Applications

This instrument is routinely used for liquid sample introduction. Major routine application fields are:

  • Simultaneous determination of 45 trace and ultra-trace elements in geological and extra-terrestrial samples (as solutions after applying appropriate sample preparation protocols). Detection limits in the low ppb-range, external precision and accuracy <1-3%, sub-mg sample weights
  • Trace and ultra-trace-elements in groundwater, seawater, hydrothermal fluids etc
  • Trace elements in life science and pharmaceutical samples
  • Chemical composition of high-tech materials

AVAATECH EDX sediment core scanner

Image of AVAATECH EDX sediment core scanner

COHERENT GeoLasPro Plus 193nm ArF excimer laser ablation (LA)

Image of COHERENT GeoLasPro Plus 193nm ArF excimer laser ablation (LA)Image of COHERENT GeoLasPro Plus 193nm ArF excimer laser ablation (LA)

Instrument

High energy 193nm ArF excimer laser ablation system

Technical Data/Features

  • beam homogenization, aperture imaging optics, 2-200μm spot size
  • high output fluence up to 40 J/cm2
  • 1-20Hz laser pulse frequency
  • standard OLYMPUS petrographic polarizing transmitted or reflected light microscope
  • automated analysis of pre-programmed target points
  • Laser ablation – inductively coupled plasma mass spectrometry (LA-ICP-MS) is a fast and very sensitive method for the direct in situ multi-element analysis of solid samples with high spatial resolution down to 4-40 μm. The sample is transferred into a sealed ablation cell with UV-transparent window on its upper side. The ablation cell is mounted onto a motorized x,y,z-microscope stage. The sample target can be observed by video or binocular using a standard petrographic polarized light microscope in either transmitted or reflected light. A pulsed high energy laser beam @ 193nm with a fluence of 1-40 J/cm2 is focused onto the sample surface and vaporizes the sample @ T>20.000K within typical crater sizes of 20-90μm. The vaporized material re-condenses forming a particulate sample aerosol that is transported by a He carrier gas stream into the ICP-MS. The He gas stream with typically 1L/min is directed through the ablation cell and subsequently mixed with Ar prior to entering the ICP. Further addition of H2 reduces oxide interferences and enhances sensitivity. The ionisation and subsequent multi-element analysis of the ablated material happens in the coupled ICP-MS as described above for the AGILENT 7500cs ICP-MS instrument. Interferences caused by non-stoichiometric sampling and elemental fractionation during laser ablation and ionisation in the ICP as well as formation of polyatomic ions in the ICP-MS depend on operating parameters of the entire system and must be carefully optimized. The system allows for single point analysis or ablation of point matrices and lines. Virtually no sample preparation is required but samples must fit into the available ablation cells. Polished sample surfaces, however, allow for better microscopic identification of the target. Detection limits are typically in the low ppb range with external error of 1-5% for analytical results.

    In near future, the laser ablation system will be coupled to the new THERMO Element XR high resolution ICP-MS instrument (see below).

    Applications

    This hyphenated analytical technique LA-ICP-MS is routinely used for the in situ microanalysis of solid materials. Major routine application fields are:

    • Simultaneous determination of 45 trace and ultra-trace elements in volcanic glass, melt inclusions in minerals, individual minerals in petrographic thin sections and their compositional zonation
    • Age dating of individual minerals / mineral zonation
    • Elemental ratios as paleo proxies in bio-carbonate (forams, corals, shells etc.)
    • Bulk analysis of materials, and of nano-particulate pressed powder pellets
    • Elemental mapping of archaeological (bones, teeth), biological (tree rings), medical samples

MAT252

Instrument

Gas source mass spectrometer equipped with a 'Kiel II' preparation line (Thermo Scientific)

Technical Data/Features

Samples are dissolved and CO2 gas is injected under vacuum into the mass spectrometer. Electron bombardement in the ion source then generates positivly charged ions from the CO2 gas, which then are accelerated within a high-tension electric field. A magnetic field separates the ions according to mass and loading. Ions of distinct mass are detected in Faraday cups.

Applications

Determination of stable carbon (13C/12C) and oxygen isotope ratios (18O/16O) in various carbonates, e.g., foraminifera, corals, shells, and sediment

MAT253

Instrument

Gas source mass spectrometer equipped with a 'CARBI IV' preparation line (Thermo Scientific)

Technical Data/Features

Samples are dissolved and CO2 gas is injected under vacuum into the mass spectrometer. Electron bombardement in the ion source then generates positivly charged ions from the CO2 gas, which then are accelerated within a high-tension electric field. A magnetic field separates the ions according to mass and loading. Ions of distinct mass are detected in Faraday cups. The instrument is equipped with 8 Faraday collectors, which allow the measuremant of 'carbonate isotopologues'

Applications

Determination of stable carbon (13C/12C) and oxygen isotope ratios (18O/16O) in various carbonates, e.g., foraminifera, corals, shells, and sediment

Neptune Plus HR-MC-ICPMS (Thermo Scientific)

Image of Neptune Plus HR-MC-ICPMS (Thermo Scientific)

Instrument

High Resolution Multi Collector ICP-MS (Thermo Scientific)

Technical Data/Features

The Thermo Scientific Neptune Plus high resolution multicollector ICP-MS (multicollector inductively coupled plasma mass spectrometer) is a double-focusing mass spectrometer, used for high precision isotope ratio measurements. Due to the high ionization energy of the plasma combined with simultaneous ion beam collection, the instrument is capable of analyzing isotope compositions of most elements of the periodic table to high precision. The instrument features high mass resolution to resolve potential molecular interferences from isotope masses of interest (e.g. 40Ar16O on 56Fe), variable multicollectors and multi ion counting capabilities (up to 8 discrete-dynode electron multipliers). The jet interface between plasma and instrument increases sensitivity 10-20 times across the entire mass range.

Application

Analysis of radiogenic isotope systems (Nd, Pb, Hf, Sr) in seawater and sediment samples, particularly at low concentrations. Measurement of stable isotope fractionation of B and Fe.

For the chemical preparation of samples for isotope analysis, modern cleanroom facilities are operational since 2009.

Nu Plasma HR-MC-ICPMS (Nu Instruments)

Image of Nu Plasma HR-MC-ICPMS (Nu Instruments)

Instrument

High Resolution Multi Collector ICP-MS (Nu Instruments)

Technical Data/Features

The Nu Plasma High Resolution MC-ICP-MS (multicollector inductively coupled plasma mass spectrometer) is a double focusing magnetic sector instrument used for high precision isotope ratio measurements. Due to the high ionization energy of the plasma combined with simultaneous ion beam collection, the instrument is capable of analyzing isotope compositions of most elements of the periodic table to high precision. The instrument is equipped with a variable dispersion ion optical Zoom lens. This allows the simultaneous, static measurement of ion beams in sixteen Faraday detectors and up to six ion-counting electron multipliers. The instrument has high resolution and pseudo resolution capabilities to resolve potential molecular interferences from isotope masses of interest (e.g. 40Ar16O on 56Fe).

Application

Analysis of radiogenic isotope systems (Nd, Pb, Hf, Sr) in seawater and sediment samples. Measurement of stable isotope fractionation of heavy elements (Si, Fe, Mo, Ba) in sedimentary, seawater and rock samples as proxies for biogeochemical (paleo-) processes.

For the chemical preparation of samples for isotope analysis, modern cleanroom facilities are operational since 2009.

THERMO Element XR High-resolution ICP-mass spectrometer (HR-ICP-SFMS)

Image of THERMO Element XR High-resolution ICP-mass spectrometer (HR-ICP-SFMS)Image of THERMO Element XR High-resolution ICP-mass spectrometer (HR-ICP-SFMS)

Instrument

Double focussing sector field high-resolution ICP-mass spectrometer (HR-ICP-SFMS)

Technical Data/Features

  • fixed low (400), medium (4000) and high (10,000) mass resolution
  • Triple detector for enhanced dynamic range covering 12 orders of magnitude
  • High response 1.5 Ghz/ppm
  • low background <0.2cps result in ultimate limits of detection < 10-15
  • New 2014 installation replacing former PlasmaTrace PT2 high resolution ICP-MS

Inductively coupled plasma – mass spectrometry (ICP-MS) is a powerful method for the determination of the (trace) element chemical composition of a sample. A mass spectrometer (MS) separates ionized elements and isotopes according to their mass-to-charge ratio (m/z) for subsequent quantification. Samples are introduced as liquids after pneumatic nebulization, or as dry aerosols after desolvation or laser ablation. The inductively coupled argon plasma (ICP) with temperatures of ∼6000 K is the ion source of the MS. Ions formed in the ICP are extracted through the interface into the high vacuum part of the MS, accelerated by high voltage and focused through an entrance slit with variable slit width towards the sector field mass filters by ion optics (quadrupole lenses for beam shaping). Ions flying on a curved flight path first pass the magnetic sector where their flight path is depending on the ions’ mass-to-charge ration (m/z). In the subsequent electrostatic sector (ESA) ions are separated according to their kinetic energy. Scanning of different masses (m/z) is accomplished by both varying acceleration voltage (E scan) and/ or the magnetic field (magnet scan). Finally, ions path through an exit slit and arrive at a triple stage detection system comprising of a Faraday detector for high ion counts and a dual stage secondary electron multiplier (SEM) for low to high count rates. The combined dynamic range of the detectors is 1012 cps. Note: This is not a multi-collector instrument. The extreme instrument response of 1.5 GHz/ppm combined with very low background counts <0.2cps results in ultimate limits of detection < 10-15. Changeable widths of both entrance and exit slits control the final mass resolution of the entire MS and can be set to 400, 4000, and 10000MR.

Application

Routinely used for ultra-trace element analysis, for determination of radionuclides (e.g., 230Th) and isotopic composition (e.g., 206Pb/207Pb, d11B, 87Sr/86Sr) for extremely small sample sizes, samples with difficult matrices (seawater, life sciences), and direct in situ micro-analysis of solids by laser ablation.