Centro di Eccellenza SMAArt (Scientific Methodologies applied to Archaeology and Art), c/o Dipartimento di Chimica, Università degli Studi di Perugia, via Elce di Sotto 8, 06123 Perugia, Italy.
Anal Bioanal Chem. 2009 Dec;395(7):2107-18. doi: 10.1007/s00216-009-3145-6. Epub 2009 Sep 29.
In the present study, the analytical strengths and limitations of near-infrared (NIR) spectroscopy to non-invasively characterize organic components in painting materials have been investigated. In spite of the increased amount of information available today from advanced modern analytical instrumentations dedicated to cultural heritage, the non-invasive identification of materials belonging to the wide class of organic compounds historically used in paintings is still a challenging task. Near-infrared spectroscopy offers several attractive features that make this technique particularly suitable to this purpose. In fact, it is non-invasive, allows for non-contact measurements in reflectance mode, gives molecular information on complex macromolecules, and can be performed on-site by means of portable devices. First-derivative transformation of reflectance spectroscopic data has been applied to provide a simple and fast way to deduce more information from NIR spectra. This approach has allowed spectral features to be identified that can be useful to distinguish different compounds belonging to the classes of lipids, proteins, and resins. To this purpose, at first, a spectral database of pure standard has been collected. Our analytical approach was then successfully validated on pictorial models reproducing the typical stratigraphy of an easel painting. As final step, the study of a real painting has been attempted and a drying oil, animal glue, and a terpenic natural resin, as well as an earth pigment were clearly identified, as cross-validated by GC-MS analysis.
在本研究中，研究了近红外（NIR）光谱技术在非侵入式分析绘画材料有机成分方面的分析优势和局限性。尽管今天从专门用于文化遗产的先进现代分析仪器中可以获得更多的信息，但对于历史上在绘画中使用的广泛的有机化合物类别的材料的非侵入式识别仍然是一项具有挑战性的任务。近红外光谱技术具有许多吸引人的特点，使其特别适合于这一目的。事实上，它是非侵入式的，可以在反射模式下进行非接触式测量，提供关于复杂大分子的分子信息，并且可以通过便携式设备在现场进行。反射光谱数据的一阶导数变换已被应用于提供一种简单快速的方法，从 NIR 光谱中提取更多信息。这种方法允许识别出可以用来区分属于脂质、蛋白质和树脂类别的不同化合物的光谱特征。为此，首先收集了纯标准的光谱数据库。然后，我们的分析方法成功地应用于复制画架画典型分层结构的模型上。作为最后一步，尝试了对一幅真实画作的研究，并通过 GC-MS 分析进行了交叉验证，明确识别出干性油、动物胶、萜类天然树脂以及一种土质颜料。
