Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milan, Italy.
Anal Bioanal Chem. 2009 Dec;395(7):2139-49. doi: 10.1007/s00216-009-3005-4.
The assessment of the influence of natural and artificial ageing on the spectrofluorescence of triterpenoid varnishes dammar and mastic is the focus of this work. Both Fourier transform infrared (FTIR) microscopy using attenuated total reflectance and Raman spectroscopy have been employed for complementary molecular analysis of samples. Synchronous fluorescence spectroscopy, excitation emission spectroscopy, and statistical analysis of data have been used to monitor changes in the optical properties of varnish samples. Assessment of naturally and artificially aged samples using excitation emission spectroscopy suggests that extensive exposure to visible light does not lead to easily appreciable differences in the fluorescence of mastic and dammar; cluster analysis has been used to assess changes, which occur with artificial ageing under visible light, indicating that differences in the fluorescence spectra of aged triterpenoids may be insufficient for their discrimination. The results highlight significant differences between the initial fluorescence of films of dammar and mastic and the fluorescence, which develops with ageing and oxidation, and specific markers, which change with ageing in FTIR and Raman spectra, have been identified.
本工作重点评估自然老化和人工老化对达玛树脂和乳香脂萜烯清漆的光谱荧光的影响。采用衰减全反射傅里叶变换红外（FTIR）显微镜和拉曼光谱法对样品进行了互补的分子分析。同步荧光光谱、激发发射光谱和数据统计分析用于监测清漆样品光学性质的变化。使用激发发射光谱法评估自然老化和人工老化样品表明，大量暴露于可见光下不会导致乳香脂和达玛树脂荧光发生明显差异；聚类分析用于评估在可见光下人工老化时发生的变化，表明老化萜类化合物的荧光光谱差异可能不足以对其进行区分。研究结果突出了达玛树脂和乳香脂薄膜初始荧光与老化和氧化过程中产生的荧光之间的显著差异，并且在 FTIR 和拉曼光谱中确定了与老化相关的特定标记物，这些标记物随老化而变化。
