The use of infrared spectroscopy and chemometrics to investigate deterioration in vegetable tanned leather: potential applications in heritage science
The use of infrared spectroscopy and chemometrics to investigate deterioration in vegetable tanned leather: potential applications in heritage science
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DOI：
10.1186/s40494-022-00690-w
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发表时间：
2022-05-24
期刊：
影响因子：
2.5
通讯作者：
High, Kirsty E.
中科院分区：
文献类型：
--
作者：
Dickinson, Elizabeth;High, Kirsty E.
植物鞣制皮革对文物收藏的保护者和策展人提出了一个独特的挑战，因为人们对它的物理和化学性质在变质后如何变化知之甚少。更好地了解退化过程对于皮革制品的保护、储存和修复具有非常重要的意义。傅里叶变换红外光谱（FTIR）与衰减全反射（ATR）一起使用，由于其相对易于应用和潜在的非破坏性，越来越多地应用于遗产领域。然而，虽然FTIR已成功地应用于了解其他蛋白质基材料（如羊皮纸）的劣化，但其在皮革分析中的应用受到限制，这主要是由于获得的光谱非常复杂。在这里，我们已经开发了多元统计方法的FTIR数据的分析从一个时间序列的皮革样品人工降解在不同的pH值。主成分分析（PCA），偏最小二乘判别分析（PLS-DA）和k-均值聚类，当一起使用时，被证明是强大的工具，在识别早期的微妙差异，在FTIR光谱皮革降解，识别差异发生随着时间的推移和不同的环境条件。我们发现，时间序列数据的k-均值聚类能够突出显示某些可能指示降解的光谱区域，而更常见的化学计量学技术则不能。我们在这里描述的方法有可能扩大FTIR的应用，作为一种快速，非破坏性和可靠的工具，用于评估考古和历史皮革物品的状况，最终导致更好地保护，储存和修复这些物品。
Vegetable tanned leather presents a unique challenge to conservators and curators of heritage collections, as little is known about how its physical and chemical properties change upon deterioration. Developing a better understanding of deterioration processes would be incredibly valuable in informing the conservation, storage, and restoration of leather objects. Fourier Transform infrared spectroscopy (FTIR) used with attenuated total reflectance (ATR) is increasingly applied in the heritage sector due to its relative ease of application and potential to be non-destructive. However, whilst FTIR has been applied successfully to the understanding of deterioration in other protein-based materials such as parchment, its application to the analysis of leather has been limited, largely due to the highly complex spectra obtained. Here, we have developed multivariate statistical methods for the analysis of FTIR data obtained from a time-series of leather samples artificially degraded at different pH values. Principal component analysis (PCA), Partial Least Squares Discriminant Analysis (PLS-DA) and k-means clustering, when used together, are demonstrated as powerful tools in identifying early subtle differences in the FTIR spectra as leather degrades, identifying differences occurring over time and between different environmental conditions. We show that k-means clustering of time series data was able to highlight some areas of the spectrum that might be indicative of degradation, which more common chemometric techniques could not. The methods we describe here have the potential to widen the application of FTIR as a fast, non-destructive and reliable tool for assessing the condition of archaeological and historical leather objects, ultimately leading to better informed conservation, storage and restoration of these objects.