López-López Maria, Özbek Nil, García-Ruiz Carmen
University Institute of Research in Police Sciences, University of Alcalá, Ctra. Madrid-Barcelona Km. 33.600, 28871 Alcalá de Henares (Madrid), Spain; Department of Analytical Chemistry, Physical Chemistry and Chemical Engineering, Multipurpose Building of Chemistry, University of Alcalá, Ctra. Madrid-Barcelona Km. 33.600, 28871 Alcalá de Henares (Madrid), Spain.
Department of Chemistry, Faculty of Arts & Science, Istanbul Technical University, 34469 Maslak, Istanbul, Turkey.
Talanta. 2014 Jun;123:135-9. doi: 10.1016/j.talanta.2014.02.025. Epub 2014 Feb 18.
Lipsticks are very popular cosmetic products that can be transferred by contact to different surfaces, being important forensic evidence with an intricate analysis if they are found in a crime scene. This study evaluates the use of confocal Raman microscopy at 780 nm excitation wavelength for the nondestructive identification of 49 lipsticks of different brands and colors, overcoming the lipstick fluorescence problem reported by previous works using other laser wavelengths. Although the lipsticks samples showed some fluorescence, this effect was not so intense to completely overwhelm the Raman spectra. Lipsticks smudges on twelve different surfaces commonly stained with these samples were also analyzed. In the case of the surfaces, some of them provided several bands to the smudge spectra compromising the identification of the lipstick. For these samples spectral subtraction of the interfering bands from the surface was performed. Finally, five different red lipsticks with very similar color were measured on different surfaces to evaluate the lipstick traceability with their smudges even on interfering surfaces. Although previous spectral subtraction was needed in some cases, all the smudged were linked to their corresponding lipsticks even when they are smeared on the interfering surfaces. As a consequence, confocal Raman microscopy using the 780 nm excitation laser is presented as a nondestructive powerful tool for the identification of these tricky samples.
口红是非常受欢迎的化妆品，可通过接触转移到不同表面，若在犯罪现场发现，经过复杂分析后它们是重要的法医证据。本研究评估了在780nm激发波长下使用共焦拉曼显微镜对49种不同品牌和颜色口红进行无损鉴定的情况，克服了先前使用其他激光波长的研究中所报道的口红荧光问题。尽管口红样品显示出一些荧光，但这种效应并不强烈，不会完全掩盖拉曼光谱。还分析了用这些样品常见染色的十二个不同表面上的口红污渍。对于这些表面，其中一些为污渍光谱提供了几个谱带，影响了口红的鉴定。对于这些样品，对来自表面的干扰谱带进行了光谱减法。最后，在不同表面上测量了五种颜色非常相似的不同红色口红，以评估即使在干扰表面上口红污渍的可追溯性。尽管在某些情况下需要先前的光谱减法，但即使口红污渍涂抹在干扰表面上，所有污渍都能与相应的口红联系起来。因此，使用780nm激发激光的共焦拉曼显微镜是鉴定这些棘手样品的一种无损强大工具。
