School of Earth and Environment

Stable Isotopes Analysis

We have a long standing track record of stable isotope analysis of carbon, sulfur, nitrogen and oxygen in a wide range of materials with applications in a number of fields. We have two mass spectrometer systems and a range of vacuum line preparation facilities:

  1. A Pyrocube elemental analyser coupled to an Isoprime mass spectrometer, currently used for isotopic analysis of C, N S in solids and O in cellulose, phosphate and nitrate
  2. A dual-inlet SIRA-10 mass spectrometer
  3. Sulfate-oxygen vacuum prep line: Barium sulphate is reacted with graphite in a vacuum to produce pure CO2 for analysis.
  4. Experimental vacuum prep line: A low volume line which is configurable for bespoke applications. Examples of previous usage are methane carbon isotopes from fluid inclusions and volatile hydrocarbons in the headspace of experimental mesocosms.
  5. Carbonate-carbon vacuum line: Samples are reacted with glacial phosphoric acid in a vacuum to produce pure CO2 for carbon isotope analysis.

Examples of common analyses

We have extensive experience of separating and purifying different pools of an element in complex natural samples to separate their isotope compositions. Examples of common analyses we undertake are given below.

  1. Sulfur in waters, sediments and organics (e.g. wood, tissue etc). In sediments we can separate elemental, metal-bound reduced (mainly pyrite), sulfate and organic sulfur pools. The organic fraction can be sub-divided using several chemical and chromatographic separations.
  2. Carbon in waters, sediments and organics. DIC and particulate carbon in waters. Carbonate and organic carbon in sediments. Tissue samples (e.g. leaves, bird claw, ants, marine bivalve soft tissue and shell organics)
  3. Nitrogen in waters, sediments and organics. Nitrate, nitrite, ammonium, dissolved organic and particulate organic nitrogen in waters. Total sediment nitrogen, kerogen nitrogen. Tissue samples (examples as for carbon)
  4. Oxygen in oxyanions: Sulfate, phosphate and nitrate in natural waters and solids. (e.g. sulfate and nitrate from surface and groundwater, sulfate in evaporate minerals, phosphate in river and waste water treatment samples)

The preparation time needed for analysis varies greatly depending on technique, element and matrix. Sample size varies in a similar way but is often on the order of a 20-100 micrograms of the element in question.

This list is by no means exclusive and we will be adding a carbonate preparation system to analyse carbonate carbon and oxygen isotopes when we replace the SIRA 10 in the next 18 months.

Contact

Please contact either Rob Newton (R.J.Newton(at)Leeds.ac.uk) or Simon Bottrell (S.H.Bottrell@Leeds.ac.uk) for further information.

Written by Dr. Robert Newton (16/06/2014)

Home