Isotope-ratio analysis for δ15N, δ13C, and δ34S in solid-phase samples starts with transformation to gas phase by extremely rapid and complete flash combustion of the sample material. Ionized combustion product is mass-analyzed by means of differing mass/charge ratios among the various isotopic species of N2, CO2, and SO2. We can analyze most ecological sample types (animal and plant tissue, soils, sediments, etc.) for carbon and nitrogen and are currently limited to organic samples (e.g., animal and plant tissue) for sulfur analysis.
Sample prep considerations
Solid samples must be oven-dried, ball-milled to less than 250 μm particle size (talc-like consistency) and weighed (~3 mg, with μg digits significant) into 9 x 5 mm tin capsules before combustion. Poor precision can often be traced to inadequate grinding that leaves fibrous matter or visible granules in the sample. Clients may send us unprocessed samples or may provide any of the above processing themselves at a major reduction in price.