Equipment Equipment

The Stable Isotope Analysis laboratories are part of the Science Analytical Facility and house a number of Isotope Ratio Mass Spectrometers for the analysis of both solid and liquid samples. The facility is split into two main areas one which focuses mainly on routine analysis, albeit for novel research, and the other is a more specialised research and development lab.

In the routine analysis lab, the laboratory team train staff and students in the analytical techniques used within the laboratory and, once trained, users can book the instruments to carry out their own analysis. Collaboration and consultancy enquiries are welcomed by the R&D lab.

The laboratories provide an analytical service to the Norwich Research Park community and enquiries are also welcome from companies outside the Research Park.

Paul Dennis is the Scientific Head of the Facility and specializes in the research and development aspects of the laboratory and is happy to discuss potential collaborative projects with interested parties.

All enquiries are also welcome and should initially be addressed to Liz Rix, Facilities Manager 01603 592540

We have the following equipment available for use

Sercon Geo 20:20

The Sercon GEO 20-20 isotope ratio mass spectrometer measures trace gas at m/z 44, 45 and 46. It is used with a modified PDZ Europa TG II preconcentration device and Gilson autosampler for isotope analysis of nitrate in freshwater and seawater samples to determine d15N, d18O andd17O using the denitrifier method (Sigman et al. 2001; Casciotti et al. 2002).

Samples are prepared using a bacterial strain that converts nitrate and nitrite in an aqueous sample to nitrous oxide gas. The nitrous oxide in the sample vial is purged from the vial with helium using a double needle, passed through a Nafion drier to remove water, through a sodium hydroxide and magnesium perchlorate scrubber to remove CO2 and residual water, a dry ice/ethanol trap (-78 ºC) as the final drying step, and a trap to remove volatile organic compounds (VOCs). The sample is preconcentrated using liquid nitrogen, passed through a gas chromatograph with a Poraplot Q column to separate out any remaining CO2 and VOCs and analysed on a GEO 20-20 isotope ratio mass spectrometer at m/z 44, 45 and 46, from which d15N and d18O values are calculated. Ford17O analysis, the nitrous oxide is passed through a gold furnace held at 800 ºC to thermally decompose the gas into molecular nitrogen and oxygen, and analysed at m/z 32, 33 and 34 from which d17O and d18O values as well as the 17O excess, D(17O) are calculated.

Samples are calibrated using the nitrate isotope reference materials IAEA-NO-3, USGS 34 and USGS 35, which are prepared and analysed alongside samples in each batch. Final results are reported with respect to Air-N2 and VSMOW (or VPDB or Air-O2, if desired). We can analyse the stable isotope composition of nitrate in various aqueous matrices including freshwater, seawater, precipitation, ice cores, snow melt, aerosols, plant extracts and ion exchange resin extracts.

Thermo Finnigan Delta V IRMS

IRMS - Thermo Finnigan Delta V connected via a conflo IV to a Thermo Finnigan GC-Isolink + Trace GC

This setup is used for compound specific isotopic measurement of:

d13C and dD in solvent based liquid samples using the Trace GC and GC-Isolink 

Thermo Finnigan Delta plus XP IRMS

IRMS - Thermo Finnigan Delta plus XP connected via a conflo IV to a Thermo Finnigan Flash EA

This setup is used for the isotopic measurement of:

d15N, d13C in solid samples using flash combustion.
d18O and dD in solid samples using pyrolysis.