Toward Chemical Signature Analysis of Forensic Evidences

Abstract

Forensic evidence analysis is vital in crime investigation and law enforcement. After the forensic evidences are collected in crime scenes and analyzed in forensic laboratory using a variety of experimental techniques, the findings and interpretation of the analytical results are used to solve a crime or dispute in a courtroom. The forensic evidences include forensic drugs, body fluids, explosives, inks, paintings, and biological agents. Most of forensic evidences are complex and contains impurities, such as cutting agents, thinners, adulterants, by-products, and intermediates (1,2). In particular, the crime scenes may include a variety of environment and condition, which may affect the forensic samples and produce impurities. The impurities of the forensic evidences can be used in chemical signature analysis as the chemical fingerprinting or profiling, which provide insightful and specific information in crime investigation. Forensic signature analysis involves analyzing the samples' composition beyond simple identification and quantitation of forensic evidences. The signature analytical data are able to categorize the forensic samples into similar groups and to offer investigative information of a common origin. In addition, the data may be used for the elucidation of the synthetic pathway or extraction method of evidences, identification of diluents, adulterants, and impurities, and identification of the evidences' geographic origin for plants-derives (1). Signature analysis of forensic samples includes physical examination and organic and inorganic analysis. The examination deals with color, shape, appearance, and other microscopic characterization of the sample. Chemical analysis of major and minor constituents reveals the information about the samples and the chemical methods used to process and preparation of samples. The information can be related to the environmental conditions prevailing the time and location. Each stage of the processing and environmental conditions of