Chitin in the fossil record: Identification and quantification of D-glucosamine

摘要: Abstract Although a labile molecule, chitin is resistant to decay when complexed with protein. Currently, qualitative evidence for the preservation of rests upon characteristic marker compounds derived through pyrolysis–gas chromatography–mass spectrometry (Py–GC–MS) fossil arthropod cuticles, supported by non-specific carbohydrate assay. However, unambiguous confirmation survival polymer requires detection its hydrolysate monomer, d -glucosamine. We have now developed GC–MS selected ion monitoring (SIM) method identification and quantification -glucosamine in materials. Fossils various ages depositional settings were investigated results compared those obtained Py–GC–MS approach. Specimens from Rancho La Brea Tar Pits (USA, Pleistocene), showed greatest degree preservation: ∼10% (w/w), while insects Willershausen (Germany, Pliocene) St Bauzile (France, Miocene) be present ∼5% (w/w). Oligocene at Enspel, Germany, revealed that more than 0.5% preserved 25 million years. The GC–MS–SIM technique confirms record explicit polysaccharide supports earlier colorimetric analyses. presence other amino sugars either exogenous (microbial) or diagenetic origin ancient specimens was also readily using This study illustrates value high-specificity quantitative ‘wet’ chemical approach combination further advance investigation record.