Hydroxyproline interference during the gas chromatographic analysis of D/L aspartic acid in human dentine.
The proportion of D- to L-enantiomers of aspartic acid in metabolically isolated proteins has been used by forensic scientists to estimate age at death. We have demonstrated the interference of a derivative of hydroxyproline (N-TFA isopropyl Hyp ester) with the N-TFA isopropyl L-Aspartic (Asp) acid ester during gas chromatography of amino acids. This has serious implications for the accurate quantification of the D- to L-Asp ratio extracted from collagenous proteins. Having demonstrated the potential for this co-elution in amino acid standards, acid-soluble dentine proteins and non-mineralised collagen, we argue that this problem can be overcome either by high resolution separation or by analysis of the (Hyp-poor) non-collagenous protein fraction.
Fossil Fuels and Environmental Geochemistry (NRG), University of Newcastle upon Tyne, UK. emma.waite@ncl.ac.uk
E R
ER
Waite
M J
MJ
Collins
A C
AC
van Duin
D001224:Aspartic Acid / Q000032:analysis* / Q000737:chemistry*; D002849:Chromatography, Gas / Q000379:methods / Q000592:standards; D003804:Dentin / Q000737:chemistry*; D005554:Forensic Medicine / Q000379:methods / Q000592:standards; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D006909:Hydroxyproline / Q000737:chemistry*; D013237:Stereoisomerism; D013696:Temperature
D001224:Aspartic Acid; D006909:Hydroxyproline