Stable Isotope Protocols | Mass Spectrometry Facility | SIU

Sample preparation suggestions

The sample amount needed for IRMS analyses is a function of how much of the element of interest is present in the sample. Please contact Dr. Mihai Lefticariu before weighing or submitting samples. Please note the Mass Spectrometry Facility does not run samples that are damaged, insufficiently prepared, or are considered to pose a hazard for the instruments if run.

1. δ¹³C, δ¹⁵N, δ²H, δ¹⁸O and weight %C, N, H, and O in solid organic and inorganic samples with natural isotope abundances by CF-EA-IRMS and CF-TCEA-IRMS

   Please make sure the samples are ground/cut as fine as possible and thoroughly dried before weighing and packing them into tin (for EA) or silver (for TCEA) capsules. The capsules containing the sample should be gently crushed into round shapes without protruding ‘spikes’ or ‘winglets’ in order to optimize their drop into the combustion tube during runs. Samples requiring demineralization as part of preparation such as soil, sediment, and coal, for example, should be thoroughly washed with deionized water and dried before packing them into capsules to remove any traces of acid.

2. δ¹³C, δ²H, weight %H and weight %C in oil samples with natural isotope abundances by CF-EA-IRMS and CF-TCEA-IRMS

   Use either a capsule designed for liquid samples or make sure that the regular capsule does not leak nor has oil on the outside.

3. δ²H and δ¹⁸O in water samples with natural isotope abundances by CF-TCEA Liquid Injection-IRMS

   Natural water samples should be filtered to remove all suspended solids and the pH measured prior to sending them to the facility. A minimum sample volume of 5 ml is recommended.

4. δ¹⁸O in water samples with natural isotope abundances by Gas Bench-Water equilibration-IRMS

   A minimum sample volume of 10 ml is recommended.

5. δ¹³C  and δ¹⁸O in carbonate samples with natural isotope abundances by off-line He flush/fill and acidification and Gas Bench-IRMS

  The mineralogic composition of the sample should be known.