The fractionation technique dating
A δ13C value, then, represents the per mille (part per thousand) deviation from the PDB standard.
PDB refers to the Cretaceous belemnite formation at Peedee in South Carolina, USA.
If, however, the entire sample is converted completely from one form to another (e.g.
In Liquid Scintillation Counting, for example, incomplete synthesis of acetylene during lithium carbide preparation may result in a low yield and concurrent fractionation.
Similarly, the transfer of gases in a vacuum system may involve fractionation error if the sample gas is not allowed to equilibrate throughout the total volume.
If it is the AMS δ13C, it cannot be used for dietary or metabolic pathway studies.
Reported δ13C values from Beta are always the values measured in the IRMS.
The extent of isotopic fractionation on the 14C/12C ratio (which must be measured accurately) is approximately double that for the measured 13C/12C ratio.