Stable isotope determinations
The atoms of an element can have different amount of neutral particles, neutrons, in their cores. Atoms with different amount of neutrons are called isotopes and non-radioactive isotopes are called stable isotopes. Even though different isotopes have similar chemical properties, small difference in mass between the atoms can cause different behaviour in physical processes and chemical reactions. As a result of this the original isotopic composition can change. The changes are usualle very small and they are measured using Isotope Ratio Mass Spectrometer (IRMS).
The change in the isotopic ratio can indicate how the compound or material was formed or what were the conditions, such as temperature. Due to this, the stable isotope ratios are commonly used when determining things like origin of substances or process chains related to them and they are also widely used in environment or atmospheric research, genuinity and origin research and industrial applications, such as food and beverage industry. Current study projects in Luomus concentrate on environmental changes determined by studying the isotope ratios in tree-rings and on the diets of past humans and animals by studying the isotope ratios of bones.
The Laboratory of Chronology offers stable isotope analyses first and foremost for scientific research projects. Collaborative research is prioritized, but time permitting the laboratory provides stable isotope analytical services also for non-collaborative research and non-academic customers.
We provide the following analyses:
- δ13C and δ15N analysis of organic solids like plant material, fungi, antlers, horns, hair and skin
- δ13C and δ15N analysis of collagen extracted from bones and teeth
- δ13C and δ15N analysis of sediments (C and N content limits apply)
- δ18O analysis of phosphate extracted from skeletal samples
- δD and δ18O analysis of organic solids like plants, insects, hair, nail, wool
- δ34S analyses of certain sulfides, sulfates and organic solids
As a rule, the laboratory accepts only natural abundance samples for analysis, i.e. isotopically labelled substances are not accepted for analysis.
Submit an inquiry of isotope analyses by filling out sample and project information through our inquiry form. Please describe your project and especially the samples in as much detail as as possible. The more information you give on your samples, the more likely it is your analyses will work out as they should. Analytical procedures vary for different sample types, e.g. bone and dentine samples, so it's important to specify the number of each type of sample.
If you are interested in analysis of organic solids (other than collagen) for δC/N/S - you must provide a best guess estimate of the weight-% of all the elements of interest in your samples for us to evaluate whether they can be analyzed or not. Search for mean values from scientific literature if you have no measurement data for your own sample set. Once you have estimates of C/N/S%, you can use this sample size calculation form to estimate the required weighing amounts of samples for analysis. Our laboratory does not process sample masses larger than 15 mg for analysis of δC/N/S. Please note that for d34S analysis of collagen requires a minimum of ca. 100 mg of relatively well-preserved bone. For specimens with poorer preservation, a much larger sample may be needed.