Chromatographic Techniques In The Forensic Analysis Of Designer Drugs PDF Download

The primary goal of the forensic drug examiner is the unequivocal identification of any controlled substance present in a drug exhibit. Most forensic laboratories routinely employ Gas Chromatography/ Mass Spectrometry (GC/MS) as the preferred method for this examination. The technique provides a rapid, semi-automated analysis of the sample and typically yields sufficient information to identify the compounds in question. However, the application of GC/MS for drug analysis does have its limitations. Certain drugs yield minimal mass spectral fragmentation patterns using electron impact MS, while other compounds, such as some diastereomers and positional isomers, are not readily differentiated technique to mass spectroscopy. Infrared spectroscopy (IR, meaning FTIR) provides an alternate technique to mass spectroscopy for the identification of organic compounds. Recent improvements in the hyphenated technique, Gas Chromatography/Infrared Spectroscopy (GC/IR) may provide a simple alternative or supplemental approach to GC/MS for identification of certain compounds. A newly introduced instrument collects GC effluent on a liquid nitrogen cooled, IR transparent window that allows the direct analysis of the deposited solid material. This technique is superior to the IR light pipe in sensitivity, IR spectral quality, and allows direct comparison of the collected spectra to existing IR databases. Our research developed procedures and protocols for the analysis of drugs and determined the benefits and limitations of this technology. The research focused on the routine identification of commonly encountered drugs, designer drugs, closely related drug isomers, as well as the fundamentals of the gas chromatography and infrared systems. Statement of purpose: The research was undertaken to develop this technology into a viable technique for the forensic community. The instrument was studied for repeatability, sensitivity, and selectivity while optimizing for analysis of a wide range of drug samples. Based upon this work the instrument proved to be a powerful forensic tool providing complimentary data to GC/MS. Acceptable levels of sensitivity, linearity, and reproducibility were achieved using the GC split-less injection mode. Concern about cross contamination of samples on the collection disk were dispelled as the deposited GC vapor produced solid "tracks" that were unique to each sample and appropriately documented by the instrument. Analytical methods were developed for the routine analyses of drugs and synthetic cannabinoids. Through these studies the instrument was verified for casework analysis and is presently in operational use in our laboratory. Software limitations hindered research progress, although software and hardware upgrades were made by the vendor (Spectra Analysis) some of which were driven by feedback provided by staff at the Vermont Forensic Laboratory (VFL).