Microchemistry and Microscopy Art Diagnostic Laboratory (M2ADL), University of Bologna, Ravenna, Italy.
Anal Bioanal Chem. 2013 Jan;405(2-3):895-905. doi: 10.1007/s00216-012-6435-3. Epub 2012 Oct 6.
We report the development of innovative embedding procedures for the analysis of paint cross sections by attenuated total reflection (ATR) Fourier transform IR microscopy. This technique was chosen because it is widely employed for the characterization and spatial location of organic and inorganic components in artistic samples. Moreover, the performance of the technique may be critically affected by sample preparation in terms of surface morphology and the presence of contamination. First, we evaluated the use of KBr as a barrier to contamination by the embedding synthetic medium. In this way, the sample cross section can be polished by means of a sample holder, which allows a controlled pressure to be applied to the sample, thus improving the reproducibility and quality of the surface cross section. In addition, argon ion milling was used for the polishing of samples embedded in KBr, and provided very promising results in terms of surface planarity and reduction of superficial contamination by KBr. Finally, the use of NaCl as an alternative to KBr was proposed thanks to its advantages in terms of hygroscopicity, cost, and toxicity. In addition, cross sections embedded in NaCl were characterized by greater hardness, a feature that allowed us to obtain improved contact with the ATR crystal.
我们报告了一种创新的嵌入程序的发展，用于通过衰减全反射（ATR）傅里叶变换红外显微镜分析油漆截面。之所以选择这种技术，是因为它广泛用于艺术样品中有机和无机成分的特征和空间定位。此外，技术的性能可能会受到样品制备的影响，包括表面形态和污染的存在。首先，我们评估了使用 KBr 作为嵌入合成介质污染的屏障。通过这种方式，可以通过样品支架对样品截面进行抛光，这允许对样品施加受控的压力，从而提高表面截面的重现性和质量。此外，还使用氩离子铣削对嵌入 KBr 的样品进行抛光，在表面平整度和减少 KBr 表面污染方面取得了非常有前景的结果。最后，由于其吸湿性、成本和毒性方面的优势，提出了使用 NaCl 作为 KBr 的替代物。此外，嵌入 NaCl 的截面具有更大的硬度，这一特性使我们能够与 ATR 晶体更好地接触。
