摘要
利用红外光谱仪及荧光分光光度计对象牙和猛犸象牙样品进行测试,通过对测试结果的比对、分析,总结二者的谱图特点,旨在探索更准确的象牙与猛犸象牙的检测方法。猛犸象牙内部由于受石化作用小,其红外光谱与象牙的没有本质区别,因此红外光谱仪在象牙饰品与猛犸象牙饰品的检测上难以提供准确信息。荧光光谱的测试结果显示,在280nm波长光的激发下,由于象牙和猛犸象牙中的氨基酸在微环境及其质量分数不同,象牙的发射光谱峰值在307nm处,猛犸象牙的发射光谱峰值在315nm处,且象牙的荧光强度高于猛犸象牙。同步荧光光谱测试中△λ分别取15,60nm,分别测试样品中的酪氨酸、色氨酸,测试结果显示两类牙质测试图谱谱形一致但强度差异明显,即荧光分光光度计在象牙和猛犸象牙的检测上可提供有效的信息。
For protection of elephant populations, the trade of ivory is prohibited, but the trade of mammoth tusk is allowed in international trade. Therefore, it is a great significant to identify ivory and mammoth tusk accurately. It is easy to distinguish the whole ivory and mammoth tusk. However, the current challenge is to identify the jewelry made of them. In this paper, the FTIR and fluorescence speetrophotometer are used to distinguish the ivory and mammoth tusk samples. The epidermis and Retzius layer of mammoth tusk and the Retzius layer of ivory are tested by FTIR. The result shows that the ivory and mammoth tusk are mainly composed of collagen and hydroxyapatite. Due to the strong fossilization, the infrared spectra have a remarkable difference between the epidermis of ivory and mam- moth tusk samples. However, the infrared spectra of interior parts of both samples are al- most same. So FTIR has a certain limitation in identification of ivory and mammoth tusk jewelry. According to different emission spectra or excitation spectra of substances under the external excitation light, fluorescence spectra can be used for nondestructive, accurate and convenient analysis. Testing samples are slices from the Retzius and the fine concentric lay-ers of the ivory and mammoth tusk. In the test, the slit width is set as 5 nm and the angle between incident light and sample surface is 45°. By 280 nm exciting light, the emission peak of the ivory is at 307 nm, but that of mammoth tusk is at 315 nm. Moreover, the former one＇s intensity is higher than the latter one. Fossilization caused damage to the collagen in the mammoth tusk partially and the micro-environment of amino acids changed. There are obvious differences in the occurrence state of amino acids between ivory and mammoth tusk. The difference between fluorescence spectra of the two samples is caused by the amino acids. The synchronous fluorescence spectrum analysis of the samples is further carried out. △λ is set at 15 nm and 60 nm and the tyrosine and tryptophan of both mammoth tusk and ivory are measured. The spectrograms of both materials show the same profile, but there are signifi- cant differences in the intensity. Tyrosine and tryptophan appear in both samples, but con- tents of them in mammoth tusk are less than those in ivory, and mirco-environment are dif- ferent from each other. This is the main reason that caused the difference in synchronous flu- orescence spectra of the samples. The result of the synchronous fluorescence spectra con- forms to the fluorescence spectra. Fluorescence spectroscopy can provide useful information of identification of ivory and mammoth tusk.
出处
《宝石和宝石学杂志》
CAS
2013年第3期50-55,共6页
Journal of Gems & Gemmology
关键词
象牙
猛犸象牙
红外光谱
荧光光谱
ivory
mammoth tusk
infrared spectrum
fluorescence spectrum
