Single-compound analysis of stable or radioactive isotopes has found application in a number of fields ranging from archaeology to forensics. Often, the most difficult part of these analyses is the development of a method for isolating the compound(s) of interest, which can derive from a wide range of sample types including the hair, nails, and bone.Here we describe three complementary preparative HPLC techniques suitable for separating and isolating amino acids from bone collagen and hair keratin. Using preparative reversed-phase, ion-pair, or mixed-mode chromatography in aqueous carbon-free mobile phases, or those from which carbon can easily be removed, underivatized single amino acids can be isolated and further analyzed using mass spectrometric techniques.
Keywords: Accelerator mass spectrometry (AMS); Amino acid (AA); Compound-specific isotope analysis (CSIA); Compound-specific radiocarbon analysis (CSRA); High-performance liquid chromatography (HPLC); Isotope ratio mass spectrometry (IRMS); Liquid chromatography-isotope ratio mass spectrometry (LC-IRMS); Mixed-mode high-performance liquid chromatography (MM-HPLC); Preparative chromatography; Radiocarbon dating; Stable isotopes; ion-pair high-performance liquid chromatography (IP-HPLC); Δ14C; δ13C.