Analytical Facilities of the Geochemistry and Isotope Geology Department

Mass spectrometers

LabOverview

Neptune Plus

The ThermoFisher Scientific Neptune Plus is a multi-collector inductively plasma mass spectrometer (MC-ICPMS) equipped with a ‚jet interface’ for enhanced sensitivity. Nine movable faraday collectors can be paired with a selection of amplifiers, ranging from 1010 to 1013 Ω. Our Neptune Plus is fitted with a multi-ion counting (MIC) array as well as a central RPQ filter and a discrete dynode multiplier that allows simultaneous detection of low intensity beams and that yield a dynamic range spanning nine orders of magnitude (from sub aA to 5 nA). The instrument is used predominantly for high-precision isotope ratio analysis in solution mode (Teledyne Cetac Aridus 3) but can also be connected to a Resonetics Resolution M50 laser ablation system.

neptuen

Element2

The ThermoFisher Scientific Element2 is a single-collector, high-resolution magnetic-sector inductively-coupled plasma mass spectrometer for multi-element trace analysis. The fast-scanning mode and a flat-top peak geometry allow the measurement of transient signals and isotope ratios. The system is equipped with a variable slit system yielding discrete mass resolutions of R = 300, 4000 and 1000, which can be used to eliminate most poly-atomic spectral interferences encountered in geological sample matrices. The dynamic range spans about eight orders of magnitude (up to ca. 108 cps) allowing the analysis of analytes ranging from pgL-1 to ngL-1. The instrument is predominantly used in combination with a Resonetics Resolution M50 laser ablation system but can also be operated in solution mode for specialised trace element analysis by multi-element isotope dilution.

Element2

iCAP-Q

The ThermoFisher Scientific iCAP-Q is a bench top, quadrupole inductively-coupled plasma mass spectrometer used for multi-element trace analysis. It is equipped with a helium kinetic energy discriminator (He KED) and a collision-reaction cell that allow the reduction of isobaric interferences and the enhancement of background equivalent concentrations. Our system is used predominantly in solution mode, linked to a ESI SC-FAST autosampler that allows the efficient sample analysis but can be linked to a Resonetics Resolution M50 laser ablation system.

icap

Triton and MAT 262

The ThermoFisher Scientific Triton is a thermal ionisation mass spectrometer (TIMS) equipped with nine movable faraday collectors that can be paired with nine 1011 and one 1012 Ω amplifiers. It is used for the isotope ratio analysis of analytes with low ionisation potential/low evaporation temperature or for elements that are affected by isobaric interferences and that cannot be measured by ICPMS methods. It is housed in a dedicated temperature stable laboratory (< 1°C/day) for high-precision isotope ratio analysis.
Our Finnigan MAT 262 is a thermal ionisation mass spectrometer (TIMS) is equipped with nine movable faraday collectors connected to 1011 Ω amplifiers. It is used for the routine analysis of radiogenic 87Sr/86Sr, 143Nd/144Nd and stable Ca isotope ratios.

triton

Argus VI

The ThermoFisher Scientific Argus VI is a static vacuum gas mass spectrometer for the high-precision determination of noble gas isotope ratios. The system is equipped with five faraday detectors linked to 1011 Ω amplifiers and is optimised for the simultaneous collection of Ar masses (36 to 40). Other noble gases (Ne, Kr and Xe) can be measured by adjusting the acceleration voltage. Our system is coupled to a self-built, large-volume gas extraction line for the analysis of Ar isotopes in low-T clay minerals.

Argus VI

ThermoFisher Scientific 253 Ultra

The 253Ultra is a new generation high-resolution double focusing gas source mass spectrometer. Using the 253Ultra we measure the ratio of 17O/16O ratio of carbonates with paleo-climatological applications.

253 Ultra

ThermoElectron MAT 253 gas mass spectrometer (H2, O2, CO2, SiF4, SF6)

The MAT253 is the workhorse in the stable isotope lab. Currently, we exclusively use our MAT253 for the high-precision measurement of triple oxygen isotopes in silicates and oxides, but also used it for the measurement of Si isotopes on SiF4. For oxygen isotopes, 0.1–2 mg samples are prepared by means of IR laser fluorination. Application fields for high-precision triple oxygen isotopes span from cosmochemistry (meteorite classification) to paleo-climatology.

253 Gas mass spec

Thermo KIEL VI mit Finnigan Delta+ gas mass spectrometer (δ13C, δ18O, carbonates)

The combination of Kiel IV and Delta+ is used for routine measurements of δ13C and δ18O of typically 50 µg carbonate samples. The device allows loading 48 samples that are run fully automatic.

KIEL VI


Laser ablation system

Resolution M50

The Resonetics Resolution M50 Laser ablation system is equipped with a 193nm ArF eximer laser (Coherent COMPex). Its optical system comprises variable, discrete spot sizes ranging from 5 to 250 μm with round or rectangular shape. Its features a small volume Laurin Cell S-155 that can accommodate standard-sized mounts, thin and thick sections as well as larger sample sizes of up to several centimetres in diameter. The laser is routinely operated in energy constant mode (with a maximum output of 80 mJ) in conjunction with our ThermoFisher Scientific Element2 for multi-element trace analysis as well as U-Pb isotope analysis in silicate materials and oxides. For better signal stability, the laser aerosol is first passed through a squid-type sample splitter before being introduced into the ICP source. The microscope can be operated in reflected and transmission light.

resolutionM50


Spectrometric methods

X-ray fluorescence spectrometry

Our PANalytical AXIOS-Advanced X-ray fluorescence spectrometer is used for the determination of major element concentrations on fused glass discs of geological matrices. The instrument is equipped with a SST mAX-4-kW rhodium target X-ray tube and seven, mostly laterally curved monochromators (PX-10, LiF 220, InSb 111, Ge 111, PE 002, PX-8 and PX-1). Flow-, scintillation-, and sealed Xe-counters are used and pulse-height selection is applied to reduce interferences from higher order spectral lines and background noise. Artificial glass discs are prepared by fluxing the samples (lithium-metaborate and –tetraborate flux) is a fully automated fusion system (Schoeps SGE 21).

xrayfluorescence


Sample preparation

LabOverview-Säulen

Clean room suite

Our metal-free, ISO class 6 clean room suite houses five ISO class 3, fully-extracted vertical laminar-flow work benches for the ultra-low blank preparation of geological samples. Each bench is equipped with two electronically-controlled thermal digestion units for sample dissolution using hot acid attack methods and for acid evaporation. Two additional ISO class 3 laminar flow stations are used for tapping of ultra-pure water (Merck Millipore Milli-Q), lab ware drying as well as for the distilling of ultrapure acids (five closed-system Savillex DST-1000). An extraction-only work bench comprises four large electronically-controlled and temperature-limited hotplates for the final stage cleaning of lab ware. The suite also comprises a balance room as well as additional table top work space and cupboards for sample preparation and the storage of lab ware.

cleanlab

Chemistry lab

Our standard chemistry laboratory comprises four fully-extracted digestion units containing six purpose-build and electronically-controlled hotplates. It is mainly used for preparatory work such as pre-cleaning of lab ware employed in our ISO class 6 clean room suite, high-pressure silicate sample digestion (Picotrace DAS) and other sample preparation steps that require a laboratory environment.

Chemistry-Lab

Rock crushing

Our rock crushing lab comprises a clipper saw for cutting of boulder-sized hand-specimen, two large-volume jaw crushers as well as a Retsch BB50 jaw crusher for the crushing of smaller sample sizes. Samples are powdered using four Fritsch Pulverisette planetary ball mills in agate-lined sample vessels.

rock crushing

Mineral separation and microdrill

Our mineral separation lab comprises a Siebtechnik cylinder mill, a self-built, fully-automated sieving table, as well as a Wilfley-style gravity shaking table for the isolation of heavy minerals in geological samples. Mineral separates can be further processed using two magnetic separators (Frantz) as well as by heavy liquid separation methods (LST) in a dedicated chemistry lab comprising two fully extracted fume hoods. Several binoculars are available for quality control of intermediary and final separation steps. The suite also houses an automated NewWave micro drill for the extraction of individual mineral phases in geological thick sections.

minseparation

IR-laser fluorination (δ17O, δ18O, δ29Si, δ30Si; silicates and oxides)

In combination with the MAT253 gas source mass spectrometer, we use an automated IR laser fluorination for preparation of O2 gas from silicates and oxides for high-precision measurements of δ17O and δ18O. Due to full automation, about 15 samples can be run per day.

IR Laser

Facilities for the preparation of polished sections

More information will follow in due course.

prep plish

Areodynamic levitation apparatus for containerless IR-laser melting of oxides and silicates

More information will follow in due course.

aerodynamic lev