Institute for Biodiversity and Ecosystem Dynamics

Isotope ratio MS

Stable isotope facilities

The isotope facility at of IBED supports the research within the Institute, at UvA as well as other academic institutions and organizations in the areas of biogeochemistry, ecology, paleoecology, microbiology and nutrition.

The measurement of stable isotopes is a useful tool in many fields of study such as ecological, forensic and biological research. The natural differences in the stable isotopic composition can be used for example to determine the geographical origin of samples like agricultural products. Labelled chemicals can be used in the investigation of pathway studies. The advantages of using labelled chemicals is that they are no more harmless as their natural form and they behave the same in the environment.

IRMS

IRMS. Photo: Jan van Arkel

Isotope Ratio Mass Spectrometry (IRMS) detector

Our laboratory is equipped with 2 isotope ratio mass spectrometers (IRMS). An IRMS detector is a high precision mass spectrometer which can measure the  in the natural abundant isotope ratio. Our systems are suitable of the measurement of light stable isotopes of carbon (12C/13C), nitrogen (14N/15N), hydrogen (1H/2H), oxygen (16O/18O) and sulfur (32S/34S). Both IRMS detectors can be coupled with different inlet instruments which makes it possible to analyze a broad range of sample types (solid, liquid, gas and compound specific).

Both IRMS detectors in our lab are continuous flow isotope ratio mass spectrometers. The IRMS is different than conventional mass spectrometers because it uses a strong electromagnetic field to separate the isotopic different masses and is simultaneously detecting the ions with multiple collector analysis. These techniques give high accuracy and precision in the measurement of stable isotopes compared to other mass spectrometers.

Technical specifications

  • Isoprime 100 (Elementar UK, Manchester, UK)
  • Bio Vision (Elementar UK, Manchester, UK)

Inlet instruments

An inlet instrument in necessary for stable isotope analysis because an IRMS detector can only measure samples that are in gaseous state. Most of our inlet instruments can be used both as a standalone instrument for quantitative analyses and can be coupled with IRMS for the combination of quantitative and isotopic ratio analysis. The inlet instruments have been optimized for accurate and precise isotopic measurement.

EA (Element Analyzer)

The elemental analyzer is a high temperature combustion unit used for the simultaneous quantitative analysis of the bulk carbon, nitrogen and sulfur in solid samples. The combusted gasses are focused and transferred to the IRMS for isotope ratio measurement.

Technical specifications

  • Vario Isotope (Elementar Analysesysteme GmbH, Hanau, Germany)

TOC (Total Organic Carbon Analyzer)

Our TOC is a high temperature combustion TOC for the analysis of organic and inorganic carbon and total nitrogen in (soil) extractions or liquid samples like freshwater or seawater. For the IRMS analysis the combusted gasses can be passed through an focusing unit and transferred to the IRMS for isotope ratio analysis. High precision (SD predominantly < 0.15‰)  and accuracy (R2= 0.9997) were achieved with this TOC-IRMS system in 13C-DOC measurements. For this various samples in a wide range of concentrations (0.2-150 mg C/L) and injection volumes (0.05-3ml) were analyzed.

The testing and development of 13DIC and 15N in Total N analysis are currently optimized.

Technical specifications

  • Vario ISOTOC Cube equipped with Low Concentration Module (LCM) for IRMS measurement (Elementar Analysesysteme GmbH, Hanau, Germany).

GC-FID/MS

GC-(quadrupole)MS system  with PTV and split/splitless injectors, can be used as stand-alone GC-MS system with FID and MS detection and/or coupled to IRMS using a GC5 interface for compound specific isotope ratio analysis of carbon, nitrogen, hydrogen or oxygen.

Technical specifications

  • Agilent 7890A gas chromatograph equipped with an Agilent 5975C MSD, (Agilent Technologies, Santa Clara, CA, United States)
  • Isoprime GC5 interface (Elementar UK, Manchester, UK).

Trace gas

Our gas pre-concentrator can concentrate gasses such as CO2 , CH4 and N2O  from gas samples using cryogenic traps. The concentrated gas is then transferred to the IRMS for the isotope ratio measurement of carbon or nitrogen. This technique can be an useful asset in incubation studies.

Technical specifications

  • Trace Gas (Elementar UK, Manchester, UK) equipped with a Gilson GX-271 autosampler (Gilson Inc., Middleton, United States).

Published by  IBED

27 November 2017