Girod Aline, Weyermann Céline
Institut de Police Scientifique, University of Lausanne, Bâtochime, CH-1015 Lausanne, Switzerland.
Institut de Police Scientifique, University of Lausanne, Bâtochime, CH-1015 Lausanne, Switzerland.
Forensic Sci Int. 2014 May;238:68-82. doi: 10.1016/j.forsciint.2014.02.020. Epub 2014 Feb 28.
Lipids available in fingermark residue represent important targets for enhancement and dating techniques. While it is well known that lipid composition varies among fingermarks of the same donor (intra-variability) and between fingermarks of different donors (inter-variability), the extent of this variability remains uncharacterized. Thus, this work aimed at studying qualitatively and quantitatively the initial lipid composition of fingermark residue of 25 different donors. Among the 104 detected lipids, 43 were reported for the first time in the literature. Furthermore, palmitic acid, squalene, cholesterol, myristyl myristate and myristyl myristoleate were quantified and their correlation within fingermark residue was highlighted. Ten compounds were then selected and further studied as potential targets for dating or enhancement techniques. It was shown that their relative standard deviation was significantly lower for the intra-variability than for the inter-variability. Moreover, the use of data pre-treatments could significantly reduce this variability. Based on these observations, an objective donor classification model was proposed. Hierarchical cluster analysis was conducted on the pre-treated data and the fingermarks of the 25 donors were classified into two main groups, corresponding to "poor" and "rich" lipid donors. The robustness of this classification was tested using fingermark replicates of selected donors. 86% of these replicates were correctly classified, showing the potential of such a donor classification model for research purposes in order to select representative donors based on compounds of interest.
指纹残留物中的脂质是增强和年代测定技术的重要目标。虽然众所周知，同一供体的指纹之间（个体内变异性）以及不同供体的指纹之间（个体间变异性）脂质组成存在差异，但这种变异性的程度仍未得到表征。因此，这项工作旨在定性和定量研究25位不同供体指纹残留物的初始脂质组成。在检测到的104种脂质中，有43种是文献中首次报道的。此外，对棕榈酸、角鲨烯、胆固醇、肉豆蔻酸肉豆蔻酯和肉豆蔻酸肉豆蔻烯酯进行了定量，并突出了它们在指纹残留物中的相关性。然后选择了10种化合物作为年代测定或增强技术的潜在目标进行进一步研究。结果表明，它们的相对标准偏差在个体内变异性方面显著低于个体间变异性。此外，使用数据预处理可以显著降低这种变异性。基于这些观察结果，提出了一个客观的供体分类模型。对预处理后的数据进行层次聚类分析，将25位供体的指纹分为两个主要组，分别对应“脂质贫乏”和“脂质丰富”的供体。使用选定供体的指纹复制品对该分类的稳健性进行了测试。这些复制品中有86%被正确分类，表明这种供体分类模型在研究目的方面具有潜力，以便根据感兴趣的化合物选择有代表性的供体。
