Vandenabeele Peter, Grimaldi Dulce Maria, Edwards Howell G M, Moens Luc
Ghent University, Laboratory of Analytical Chemistry, Proeftuinstraat 86, B-9000 Ghent, Belgium.
Spectrochim Acta A Mol Biomol Spectrosc. 2003 Aug;59(10):2221-9. doi: 10.1016/s1386-1425(03)00066-0.
Dispersive Raman spectra of six copal resins, that were purchased in local markets in Mexico, are presented. The spectra were interpreted and compared with each other. For all these spectra, the relative intensity of the Raman band at approximately 1645 cm(-1), attributed to the exomethylene nu(C=C) stretching vibration, was rather low, especially as fresh samples are involved. In one resin, viz. Incienso, CaCO3 was detected. Probably this inorganic pigment was added as a whitener. In the spectrum of Lágrima a starch fraction was present. Raman spectra of a sample from an Aztec figurine were recorded. It was shown that its composition was inhomogeneous at the micrometer level. Here, too, CaCO3 was observed. It was not possible to identify the resin applied in the antique figurine due to material degradation by age and environmental exposure.
本文展示了在墨西哥当地市场购买的六种柯巴脂树脂的色散拉曼光谱。对这些光谱进行了解释并相互比较。对于所有这些光谱，归因于亚甲基ν(C=C)伸缩振动的拉曼峰在约1645 cm(-1)处的相对强度相当低，尤其是涉及新鲜样品时。在一种树脂（即Incienso）中检测到了CaCO3。可能添加这种无机颜料作为增白剂。在Lágrima的光谱中存在淀粉成分。记录了一件阿兹特克小雕像样品的拉曼光谱。结果表明，其在微米级别的成分是不均匀的。在此也观察到了CaCO3。由于年代久远和环境暴露导致材料降解，无法确定用于这件古董小雕像的树脂。
