| Three different methods can be used to quantify the extent of amino acid racemization present in geological samples: gas chromatography (GC), reverse-phase liquid chromatography (RPLC) and ion-exchange liquid chromatography (IELC). Data obtained from any method can be used for geochronological and paleoclimate purposes. Each method resolves the diastereomer D-alloisoleucine/L-isoleucine (A/I), thus by conducting high temperature heating experiments the three methods can be directly compared. Furthermore, since GC and RPLC also resolve enantiomers, kinetic data can be obtained for multiple amino acids. Mercenaria mercenaria (Mm), Ensis directus (Ed), Macoma nasuta (Mn) and Protothaca staminea (Ps), mollusks from the Atlantic and Pacific coasts, are used in this study since they are commonly used in aminostratigraphic studies. (Abstract shortened by UMI.)... |
