Chemical Forensics

Chemical warfare agents (CWAs) have lately been used in the Syrian Arab Republic, the Republic of Iraq, Malaysia, and the United Kingdom. In the two latter cases, normal investigation by authorities, such as evidence collection and identification of unknown materials found at the crime scenes, was possible. However, in Syria and Iraq the inspectors from the Organization for the Prohibition of Chemical Weapons (OPCW) collected evidence in a hostile environment and under tight time constraints. The collected samples were analyzed at the OPCW’s designated laboratories under a strict scope of analysis. The verification protocol for determining the presence or absence of Chemical Weapons Convention (CWC) related chemicals includes sample preparation followed by analysis by different chromatographic, spectrometric, and spectroscopic techniques. According to the rules of the OPCW for the sample analyses, the identification is considered unambiguous if two different analytical techniques giving consistent results confirm the presence of the same chemical.

The term “chemical forensics” is defined as an application of chemistry and forensic toxicology in a legal framework. Various research techniques and methods have potential for forensic crime scene investigations related to CWC and alleged use of CWAs. In this review, the forensic information about chemical analyses obtained from the public reports of the OPCW and scientific publications on recent studies related to CWAs, illicit drug profiling, poisons, and incapacitating chemicals, as well as chemical profiling of precursors, impurities, and side products are presented. Finally, the need for recommended operation procedures for attribution analysis for sampling, sample preparation, complementary analytical methods, data analysis, reporting, quality control, and proficiency tests similar to those of CWA analysis from environmental and biomedical samples is discussed.