Department of Chemistry, University at Albany, SUNY , 1400 Washington Avenue, Albany, New York 12222, United States.
Anal Chem. 2017 Feb 7;89(3):1486-1492. doi: 10.1021/acs.analchem.6b02986. Epub 2017 Jan 11.
The development of novel methods for forensic science is a constantly growing area of modern analytical chemistry. Raman spectroscopy is one of a few analytical techniques capable of nondestructive and nearly instantaneous analysis of a wide variety of forensic evidence, including body fluid stains, at the scene of a crime. In this proof-of-concept study, Raman microspectroscopy was utilized for gender identification based on dry bloodstains. Raman spectra were acquired in mapping mode from multiple spots on a bloodstain to account for intrinsic sample heterogeneity. The obtained Raman spectroscopic data showed highly similar spectroscopic features for female and male blood samples. Nevertheless, support vector machines (SVM) and artificial neuron network (ANN) statistical methods applied to the spectroscopic data allowed for differentiating between male and female bloodstains with high confidence. More specifically, the statistical approach based on a genetic algorithm (GA) coupled with an ANN classification showed approximately 98% gender differentiation accuracy for individual bloodstains. These results demonstrate the great potential of the developed method for forensic applications, although more work is needed for method validation. When this method is fully developed, a portable Raman instrument could be used for the infield identification of traces of body fluids and to obtain phenotypic information about the donor, including gender and race, as well as for the analysis of a variety of other types of forensic evidence.
新型法医学方法的发展是现代分析化学中一个不断增长的领域。拉曼光谱是少数几种能够对包括体液痕迹在内的各种法医证据进行非破坏性和几乎即时分析的分析技术之一。在这项概念验证研究中，拉曼显微镜用于基于干血迹进行性别识别。从血迹的多个点以映射模式采集拉曼光谱，以说明样品的固有异质性。获得的拉曼光谱数据显示，女性和男性血液样本的光谱特征高度相似。然而，应用于光谱数据的支持向量机（SVM）和人工神经网络（ANN）统计方法能够高度置信地区分男性和女性血迹。更具体地说，基于遗传算法（GA）与 ANN 分类相结合的统计方法对单个血迹的性别区分准确率约为 98%。这些结果表明，该方法在法医应用中具有巨大的潜力，尽管还需要进一步验证。当该方法完全开发后，便携式拉曼仪器可用于现场识别体液痕迹，并获得供体的表型信息，包括性别和种族，以及用于分析各种其他类型的法医证据。
