Department of Chemistry, University at Albany, SUNY, 1400 Washington Avenue, Albany, NY 12222, USA.
Analyst. 2010 Mar;135(3):512-7. doi: 10.1039/b919393f. Epub 2009 Dec 15.
The potential use of Raman spectroscopy for nondestructive, confirmatory identification of body fluids at the crime scene has been reported recently (Virkler and Lednev, Forensic Sci.,Int., 2008, 181, e1-e5). However, those experiments were performed using only one sample of each body fluid and did not investigate the potential for spectral variations among different donors of the same fluid. This paper reports on the role of heterogeneity within a single human saliva sample as well as among samples from multiple donors. Near-infrared (NIR) Raman spectroscopy was used to measure spectra of pure dried human saliva samples from multiple donors in a controlled laboratory environment. Principal component analysis of spectra obtained from multiple spots on dry samples showed that dry saliva is heterogeneous and its Raman spectra could be presented as a linear combination of a fluorescent background and three spectral components. The major chemical components known to be present in saliva were used to tentatively identify the principal spectral components. The issue of potential spectral variations that could arise between different donors of saliva was also addressed. The relative contribution of each of the three components varies with donor, so no single spectrum could effectively represent an experimental Raman spectrum of dry saliva in a quantitative way. The combination of these three spectral components could be considered to be a spectroscopic signature for saliva. This proof of concept approach shows the potential for Raman spectroscopy to identify an unknown substance to be saliva during forensic analysis.
最近有报道称，拉曼光谱在犯罪现场对体液进行非破坏性确证识别方面具有潜在的应用价值（Virkler 和 Lednev，《法医学杂志》，2008 年，181 期，e1-e5）。然而，这些实验仅使用每种体液的一个样本进行，并未研究同一体液的不同供体之间光谱变化的可能性。本文报告了单个人类唾液样本内部以及多个供体样本之间的异质性的作用。近红外（NIR）拉曼光谱用于在受控的实验室环境中测量来自多个供体的纯干燥人唾液样本的光谱。对干燥样品上多个点获得的光谱进行主成分分析表明，干燥唾液是不均匀的，其拉曼光谱可以表示为荧光背景和三个光谱分量的线性组合。已知存在于唾液中的主要化学成分被用于初步确定主要光谱分量。还解决了唾液不同供体之间可能出现潜在光谱变化的问题。三个组成部分中的每一个的相对贡献随供体而变化，因此没有单个光谱可以有效地以定量方式表示干燥唾液的实验拉曼光谱。这三个光谱分量的组合可以被认为是唾液的光谱特征。这种概念验证方法表明，拉曼光谱在法医分析中有可能识别未知物质是否为唾液。
