The use of liquid phase separation techniques for heroin chemical profiling

Abstract

Drug profiling involves the gathering of chemical and physical information, mainly via chemical analyses, to assist intelligence and law enforcement agencies in identifying the origin of illicit drugs. With heroin being one of the most widely abused drugs, its physical analysis, such as visual observations, and chemical profiling methods such as isotope ratio mass spectrometry, based on isotope abundance of natural products such as opium, and chromatographic profiles is essential to determine geographic origins and disrupt drug trafficking routes. Chromatographic methods such as gas chromatography and liquid chromatography determine the major alkaloids, acidic and neutral manufacturing by-products, and occluded solvents in an illicit heroin sample. Drug profiling can also be used to determine the synthetic routes or precursors used in synthetic or semi-synthetic drugs such as methamphetamine or fentanyl. Liquid phase separation techniques are used in a variety of forensic disciplines, including drug profiling. These techniques are advantageous to gas separations in that they allow the analysis of solutes that are thermally degradable, polar, and non-volatile. Additionally, the mobile phase can play a major role in the separation process as opposed to mobile phases used in gas chromatography. Liquid phase separations can also be compatible with aqueous samples and derivatization is not required. These aspects, along with ultraviolet and mass spectrometric detection, make liquid phase techniques attractive for heroin profiling. This critical review will provide an overview of heroin profiling using liquid phase separation techniques, along with the various detectors coupled with these techniques. The benefits and limitations of liquid phase separation techniques will be considered, as well as future directions.