Laboratory analytical services

• Bulk elemental and stable isotope analysis

  We regularly quantify the carbon (C), nitrogen (N) and sulphur (S) content and associated isotopic ratios (¹³C/¹²C, ¹⁵N/¹⁴N) in a variety of solid and liquid materials.

  Examples include:

  • C/N/S in soils and sediments
  • C/N/S in river and marine suspended sediment
  • Dissolved C/N in fresh, brackish, salt, and brine waters
  • δ¹³C and δ¹⁵N of soils, sediment and suspended particulate matter

• Ramped thermal analysis

  We offer a range of cutting edge ramped thermal analysis approaches which can be used to characterise a material's composition. The laboratory regularly undertakes three types of thermal analysis:

  • Temperature dependent combustion (TDC) - TDC analysis ramp heats and holds a furnace at defined temperatures up to 900^oC in oxygenated or inert atmospheres allowing organic carbon fractions to combust or inorganic carbon fractions to decompose. The released CO₂ is measured using an infrared analyser and can be quantified into temperature-dependent fractions. Following the standard operating procedure, three temperature fractions would be measured: 50-400^oC (total organic carbon), 400-600^oC (residual or elemental organic carbon) and 600-900^oC (inorganic carbon). Depending on the task, the number of temperature fractions can be user defined.
  • Thermogravimetric analysis (TGA) - Thermogravimetric analysis ramp heats sample material and continuously measures changes in mass during combustion of the material. The TGA is regularly heated at a rate of 5 or 10^oC min^-1 under a constant flow of N₂ (20ml min^-1). Both the rate at which the sample material is heated and the atmosphere (Air, N₂, O₂, Ar) can be adjusted as required.
  • Ramped oxidation/pyrolysis combustion (ROx/RPO) - This technique ramp heats sample material at a consistent rate (normally 5 or 10^oC min^-1) either under an oxygenated (ROx) or inert (RPO) atmosphere. As the sample material combusts the CO₂ produced is continuously measured using infrared spectrometry. During combustion, the evolved gas can be captured for secondary analysis. Depending on the measurements required, the atmosphere and ramp rate can be adjusted.

• Particle characterisation

  The particle characterisation facilities within the School are capable of measuring the size of a particle between 0.04 to 2000µm using laser particle size analysis. For particles greater than 2000µm wet and dry sieving is utilised. This type of analysis is regularly applied to:

  • Marine sediments
  • Riverbed sediments
  • Soils
  • Volcanic tephra
  • Microplastics

  Particle shape and morphology can be determined using Flow Imaging Microscopy. The laboratory is equipped to image particles between 0.03 and 100µm. Examples of this analysis include:

  • Size and morphology of tephra shards
  • Diatom abundance and identification in fresh and brackish waters
  • Mineral organic matter interactions
  • Microplastic quantification

• Radionuclide dating

  We regularly measure radioactive isotopes Caesium-137 (¹³⁷Cs), Lead-210 (²¹⁰Pb), Amercium-214 (²¹⁴Am) and Lead-214 (a mediator for Ra-226). Caesium-137 and Amercium-214 are man-made radionuclides created by atmospheric testing of nuclear weapons or accidental releases from nuclear power stations that can be used to date soils and sediments deposited since 1950. Lead-210 is a naturally occurring radionuclide that is part of the ²³⁸U decay series and can date sediments up to 150 years old.

  Examples of recent applications include:

  • Dating fjord and lake sediments
  • Identifying radionuclides from contaminated soils

• Compositional analysis

  We offer a range of approaches to determine the composition of solid and liquid sample material using a range of techniques including XRF, py-GCMS and UV/Vis and NIR spectrophotometry. 

  Recent examples of this work include:

  • Characterisation of the aromaticity of dissolved organi matter (UV/Vis)
  • Microplastic identification (py-GCMS)
  • Heavy metal pollution in soils and sediments (XRF)
  • Arsenic quantification in historic books (XRF, NIR)
  • Chlorophyll quantification (UV/Vis)
  • Organic matter quantification in soil (NIR)