Radiocarbon dating sample preparation
However, if requested we can isolate and date the total organic fraction or the humic fraction of the sample.
These are pretreated using a dilute acid/dilute alkali/dilute acid treatment (commonly termed ABA).
Humic acid is isolated by collecting the Na OH fitrate which is acidified with HCl to precipitate the humic fraction, then rinsed and dried. Rapid sample preparation of dissolved inorganic carbon in natural waters using a headspace-extraction approach for radiocarbon analysis by accelerator mass spectrometry.
Marine shell samples are routinely etched with dilute HCl to minimise the possibility of contamination through isotopic exchange between the sample and its environment.
Freshwater and terrestrial shells may obtain their carbon from a source (or reservoir) that is not well documented and may give results that are difficult to interpret.
More information on reservoir effects can be found here.