Forensic Drug Identification by Gas Chromatography - Infrared Spectroscopy

• NCJ Number: 242698
• Author(s): Robert Shipman; Trisha Conti; Tara Tighe; Eric Buel
• Date Published: June 2013
• Length: 63 pages
• Grant Number(s): 2008-DN-BX-K161
• Agencies: NIJ-Sponsored
• Publication Type: Report (Technical Assistance); Report (Grant Sponsored)

Annotation

This research tested the effectiveness of using gas chromatography - infrared spectroscopy (GC/IR) to identify a controlled substance present in a drug exhibit.

Abstract

The GC/IR instrument developed proved to be a powerful forensic tool for identifying controlled substances, providing complementary data to gas chromatography - mass spectrometry (GC/MS), which has been the preferred method for identifying controlled substances; however, the application of GC/MS for drug analysis has limitations. Certain drugs yield minimal mass spectral fragmentation patterns using electron impact MS; and other compounds, such as some diastereomers and positional isomers, are not readily differentiated by mass spectroscopy. 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. The instrument was tested for repeatability, sensitivity, and selectivity while optimizing for the analysis of a wide range of drug samples, including commonly encountered drugs, designer drugs, and closely related drug isomers. Through the studies conducted, the instrument was verified for casework analysis and is currently being used in the researchers' laboratory. 25 figures, 9 tables, 18 references, and information on the dissemination of research findings