Carolan V A, Gardner M L, Lucy D, Pollard A M
School of Science and Mathematics, Sheffield Hallam University, UK.
J Forensic Sci. 1997 Jan;42(1):10-6.
An HPLC method is described for simultaneously obtaining the enantiomeric ratio of three amino acids (aspartic acid, serine, and glutamic acid) from dental collagen, with a view to using this information for estimating age at death. Results are reported from a sample of twenty three known age modern teeth, six known age 19th C. AD teeth, and two unknown age Romano-British teeth. It was found (as expected) that all three D/L ratios changed significantly with chronological age. Standard calibration techniques were used to estimate ages for the six 19th C. AD specimens from regression equations estimated from the modern specimens, and also to predict (for the first time) the error associated with such estimates. Errors using aspartic acid were found to be similar to those obtained by other methods of age estimation from dental evidence, serine, and glutamic acid providing much poorer age estimates. Additionally, a systematic difference in the age-enantiomeric ratio relationship was observed between modern and older dental samples. It is concluded that there is some fundamental difference in the observed enantiomeric ratios between modern teeth and older samples, possibly as a result of the chemical alteration of the dental proteins.
描述了一种高效液相色谱法，用于同时测定牙胶原中三种氨基酸（天冬氨酸、丝氨酸和谷氨酸）的对映体比例，旨在利用这些信息估计死亡年龄。报告了来自23颗已知年龄的现代牙齿样本、6颗已知年龄的公元19世纪牙齿样本以及2颗未知年龄的罗马-不列颠时期牙齿样本的结果。结果发现（正如预期的那样），所有三种D/L比值均随年代年龄显著变化。使用标准校准技术，根据从现代样本估计的回归方程，对6颗公元19世纪的样本进行年龄估计，并首次预测了与此类估计相关的误差。发现使用天冬氨酸时的误差与通过其他从牙齿证据估计年龄的方法所获得的误差相似，而丝氨酸和谷氨酸提供的年龄估计则差得多。此外，在现代和较古老的牙齿样本之间，观察到年龄与对映体比例关系存在系统差异。得出的结论是，现代牙齿和较古老样本中观察到的对映体比例存在一些根本差异，这可能是由于牙齿蛋白质的化学变化所致。
