Conventional racemization analysis tends to report a D-alloisoleucine / L-isoleucine (A/I or D/L ratio).
Reverse phase HPLC techniques can measure up to 9 amino acids useful in geochronology over different time scales on a single chromatogram (aspartic acid, glutamic acid, serine, alanine, arginine, tyrosine, valine, phenylalanine, leucine) [REF].