Conti Claudia, Botteon Alessandra, Colombo Chiara, Realini Marco, Matousek Pavel
Consiglio Nazionale delle Ricerche, Istituto per la Conservazione e la Valorizzazione dei Beni Culturali (ICVBC) , Via Cozzi 53, 20125, Milano, Italy.
Central Laser Facility, Research Complex at Harwell, STFC Rutherford Appleton Laboratory , Harwell Oxford, OX11 0QX, United Kingdom.
Anal Chem. 2017 Nov 7;89(21):11476-11483. doi: 10.1021/acs.analchem.7b02700. Epub 2017 Oct 23.
A recently developed technique of Micro-Spatially Offset Raman Spectroscopy (micro-SORS) extends the applicability of Raman spectroscopy to probing thin, highly diffusely scattering layers such as stratified paint samples, enabling their nondestructive chemical characterization. The technique has a wide applicability across areas such as cultural heritage, polymer research, forensics, and biological fields; however, currently, it suffers from a major unaddressed issue related to its ineffectiveness with highly heterogeneous samples. In this paper, we address this unmet need while demonstrating an effective strategy to probe such samples, involving a mapping on scales substantially larger than the scale of heterogeneity. This approach provides an effective means of obtaining robust and representative micro-SORS datasets from which sample composition can be effectively deduced, even in these extreme scenarios. The approach is compared with a basic point collection approach on two-layer paint systems where different layers-top, bottom, or both-are heterogeneous. The study has particular relevance to cultural heritage, where heterogeneous layers are often encountered with painted stratigraphies.
一种最近开发的微空间偏移拉曼光谱技术（micro-SORS）将拉曼光谱的适用性扩展到探测薄的、高度漫散射层，如分层涂料样本，从而实现对其进行无损化学表征。该技术在文化遗产、聚合物研究、法医学和生物领域等具有广泛的适用性；然而，目前它面临一个主要的未解决问题，即对高度异质样本无效。在本文中，我们在展示一种探测此类样本的有效策略的同时，解决了这一未满足的需求，该策略涉及在远大于异质性尺度的规模上进行映射。即使在这些极端情况下，这种方法也提供了一种有效的手段来获取可靠且具有代表性的微空间偏移拉曼光谱数据集，从中可以有效地推断出样本组成。在两层涂料系统中，将这种方法与基本的点采集方法进行了比较，其中不同的层——顶部、底部或两者——都是异质的。该研究与文化遗产特别相关，在文化遗产中，绘画地层中经常会遇到异质层。
