物证的无损鉴定中爆炸物、毒品、药水和笔迹检测方案

HORIBAAutomotive Test Systems 1 Process & Environmental 1 Medical 1 Semiconductor l Scientific Raman Spectroscopy Applied to Forensic Sciences Ophelie Lancry， Application Scientist - HORIBA Jobin Yvon SAS， 231 rue de Lille， Villeneuve d'Ascq， France Raman Spectroscopy is a scattering technique probing the vibrational modes of molecules and crystals.Raman signatures provide information about the chemical nature and the crystalline structure of samples.This characterisation method is fast，non-destructive and does not requireany particular sample preparation. Confocal Raman microscopy allows sub-micron features and objectsanalysis and leads to high spatial discrimination within heterogeneoussamples， not only at the surface but also in depth. maigge P'of lase Ocus P matlatcchteess exactly the confoca o Raman mapped imaging of explosive materials 530 In this example， a contaminated surface with explosives is analysed. The distributionof indidual components is done with step size interval of 0，5 pm. umber kcm 250 PETN： Pentaerythritol tetra nitrate Drug analysis through glass vial Confocal Raman microspectroscopy enables analyzing in depth， and this examplethrough glass vial. High Sensitivity High resolution (1800 gr/mm) The high throughput， the low-signal detection and the strong illuminationof Horiba Jobin Yvon Raman systems provide a very high sensitivity whichallows fast analysis on weak traces of materials with a good S/N ratio. The chemical image above shows the distribution of three substances (withina mixture) generated using the integrated intensity of their characteristic Ramanbands. Cocaine， Amphetamine and Caffeine particles of few micrometers areidentified and localized. High Raman Selectivity Raman spectroscopy can be used for the identificationof chemical species； its high spectral resolutionallows closely related chemical substances to bedistinguished. Furthermore， this method is sensitiveto m1acromolecular structure： chains orientation，crystallinity properties can be investigated by Ramanspectroscopy. & Identification of drugs Wavenumber (cm) Fast and easy chemical identification can be achieved usingRaman spectroscopy. This first example shows the spectraof different drugs related to cocaine： all of them havecharacteristic features enabling straightforward identificationof unknown material. .Identification of black inks The second example shows how it is easy to identify anunknow black ink by Raman spectroscopy. Instrumental key featuresfor Raman measurements inForensics . Spectral resolution： identification of chemicallyrelated (and similar) substances like polymorphs orcouples precursor/final compound Spatial resolution： depends on analysed particles Sensitivity： sometime only traces amounts of thesample are available Confocality： analysis through glass vial or plastic bagAnalysis of particles embedded in a matrix Spectral Libraries Multi laser excitation to reduce/avoid fluorescence