Isolation and isotopic analysis of individual amino acids from archaeological bone collagen: A new method using RP-HPLC

This paper presents a new method for the isolation and isotopic analysis of some individual amino acids from proteins. The technique and its constitue nt steps are discussed; then isotopic analyses of amino acids from several samples of bone collagen from the Late Roman site of Poundbury, Dorset, UK are presented. The applications of the method are discussed, as well as som e advantages of this technique relative to other methods. Although develope d for use with archaeological bone collagen, the technique is equally appli cable to other proteinaceous materials. The use of reversed-phase HPLC avoi ds problems of isotopic fractionation inherent in using ion-exchange HPLC. Amino acids are isolated preparatively, allowing both carbon and nitrogen i sotopic values to be measured on a single sample using CF-IRMS. Since amino acids are isotopically analyse in a underivatized form (unlike GC-C-IRMS), the method also presents the possibility of collecting the CO2 generated d uring CF-IRMS: this would allow the subsequent dating by C-14-AMS of indivi dual amino acids isolated from archaeological samples.