Isotope fractionation by XAD-2 treatment
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XAD-2 resin is considered the good materials to separate quantitatively the polar amino acids from the less polar fulvic and humic acids. To evaluate if XAD-2 treatment affects isotope values, δ ^<13>C and δ ^<15>N were measured on bulk sample by a simple preparation, gelatin-collagen extracted by usual method, decalcified bone powder and XAD-purified hydrolysates from a modern well-preserved ivory sample "IVRY-1". Among three fractions of bulk, gelatin-collagen and decalcified ivory powder, there are almost no difference in both δ ^<13>C and δ ^<15>N. On the other hand, XAD-treated hydrolysate has apparently more positive δ ^<13>C and δ ^<15>N values than the three fractions. However, it is doubt whether the result is due to isotope fractionation by XAD-2 treatment because the fulvic and humic contamination in the collagen might affect isotope values of bulk, gelatin-collagen and decalcified ivory powder. The C/N ratio in fulvic and humic phases is significantly more higher than collagen. In the next study, we have to study modern collagen standards or amino acid standards to evaluate if XAD-2 resin introduce isotope fractionation.
- Summaries of Researches using AMS at Nagoya University
Summaries of Researches using AMS at Nagoya University 9 308-311, 1998-03