@article{oai:nagoya.repo.nii.ac.jp:00011531,
 author = {中村, 俊夫 and Nakamura, Toshio and 太田, 友子 and Ohta, Tomoko and 宮本, 雅三 and Miyamoto, Masazo and 南, 雅代 and Minami, Masayo and 小田, 寛貴 and Oda, Hirotaka and 池田, 晃子 and Ikeda, Akiko},
 journal = {名古屋大学加速器質量分析計業績報告書},
 month = {Mar},
 note = {We have conducted ^<14>C dating, with a Tandetron accelerator mass spectrometer (AMS) at Nagoya University, on carbon from collagen fractions extracted from a molar tooth fossil of Naumann's elephant (Palaeoloxodon naumanni) collected from the Uwa-sea, offshore Natori-Kajitanihana, Nishi-Uwa-gun, Ehime prefecture. The molar fossil was cleaned on the surface with a steel brush and a dental grinder, treated with 0.5M NaOH solution, and ground into powder. Two sets of the powdered sample, about 3.8g and 4.9g each, were demineralized with 1.2N HCl in a cellulose tube to extract collagen. After demineralization, HCl was completely removed from the tube by dialysis. Then the solution fraction in the tube was separated by centrifuge, and freeze-dried to get a solution-collagen fraction. Solid remains were put in a Pyrex tube with 20ml of distilled water and heated at 90℃ for 10 hours to extract the water soluble gelatin-collagen fraction. Collagen was oxidized, using CuO to produce CO_2,in a Vycor tube at 950℃ for an hour. A small aliquot of the CO_2 was analyzed for its' stable carbon isotope ratio, δ ^<13>C_<PDB>, using a triple-collector mass spectrometer (MAT-252). To produce graphite, the remaining CO_2 was reduced by hydrogen, with an Fe-powder catalyst, in a Vycor tube at 650℃ for several hours. The sample graphite was analyzed for its' ^<14>C/^<13>C ratio, relative to that of an oxalic acid standard (NBS-SRM-4990). In general, reliable ^<14>C dates can be obtained for collagen fractions extracted from the fossil sample, provided that the collagen fractions have been preserved well from weathering in nature. Experimental yields of collagen fractions were relatively high, ranging from 1.22 to 1.51%. The CO_2 yield from the gelatin collagen fraction was 42%, being consistent with the values of 41-42% for gelatin collagen extracted from fresh bone samples. On the other hand, the CO_2 yield from the solution fraction was 25%, being lower than the values of 41-42%. Thus the ^<14>C date of 29,200±870 yr BP, obtained for the gelatin collagen fraction, seems to be reliable and can be assigned as the age of the molar fossil sample, though the ^<14>C date is about 4,000 years older than the value of 24,880±580 yr BP obtained for the solution collagen fraction. The δ ^<13>C_<PDB> values of -20.2‰ for the both gelatin and solution collagen fractions were consistent with accepted δ ^<13>C_<PDB> values, of from -21 to -23‰ for herbivorous mammals., タンデトロン加速器質量分析計業績報告 Summaries of Researches Using AMS 1997 (平成9)年度},
 pages = {286--297},
 title = {愛媛県西宇和郡三崎町名取梶谷鼻沖で採取されたナウマン象の臼歯のAMS ^<14>C年代},
 volume = {9},
 year = {1998}
}