Villar Susana E Jorge, Edwards Howell G M, Seaward Mark R D
Department of Chemical and Forensic Sciences, University of Bradford, Bradford BD7 1DP, UK.
Spectrochim Acta A Mol Biomol Spectrosc. 2004 Apr;60(5):1229-37. doi: 10.1016/j.saa.2003.08.005.
Seven highly-coloured lichen species belonging to the genera Caloplaca, Candelariella, Aspicilia and Xanthoria from ecclesiastical buildings in northern Spain have been analysed non-destructively by FT-Raman spectroscopy. The vibrational band assignments in the spectra of the specimens, which were still attached to their limestone or sandstone substrata, were accomplished with the assistance of the chemical compositions obtained from wet chemical extraction methods. beta-Carotene was found in all specimens as the major pigment, and the characteristic spectral signatures of calcium oxalate monohydrate (whewellite) and dihydrate (weddelite) could be identified; chemical signatures were found for these materials even in lichen thalli growing the non-calcareous substrata, indicating, probably, that the calcium was provided here from wind-or-rain-borne sources. The Raman spectral biomarkers found in the lichens broadly agreed with the chemical extraction profiles as expected, but the present study indicates that some form of non-destructive taxonomic identification based on Raman spectroscopy was possible.
对来自西班牙北部宗教建筑的7种颜色鲜艳的地衣物种（属于Caloplaca属、Candelariella属、Aspicilia属和Xanthoria属）进行了傅里叶变换拉曼光谱无损分析。借助湿化学提取方法获得的化学成分，完成了仍附着在石灰岩或砂岩基质上的标本光谱中的振动带归属。在所有标本中均发现β-胡萝卜素是主要色素，并且可以识别一水合草酸钙（水草酸钙）和二水合草酸钙（韦氏草酸钙）的特征光谱特征；即使在生长于非钙质基质上的地衣叶状体中也发现了这些物质的化学特征，这可能表明这里的钙是由风或雨携带的来源提供的。地衣中发现的拉曼光谱生物标志物与预期的化学提取谱大致相符，但本研究表明基于拉曼光谱的某种形式的无损分类鉴定是可能的。
