In the United States, a vast network of forensic labs at the city, county, state, and national levels is taxed with the analysis of record numbers of samples of prohibited substances. Following proper analysis and identification of each substance, conclusive findings must be presented in U.S. courts. For proper criminal proceedings, identification of active ingredient samples and other species, such as adulterants, excipients, and reaction byproducts, must be definite and conclusive. It is imperative that analysis of seized substances be performed and determined accurately.
In order to meet the stringent requirements of the court system, most forensic labs currently follow the recommendations outlined by the Scientific Working Group for the Analysis of Seized Drugs (SWGDRUG)1 for the qualitative and quantitative analysis of seized drugs (see www.SWGDRUG.org). For conclusive qualitative analysis, SWGDRUG requires 1) a minimum of two analytical methods to form an acceptable analytical method, and 2) that each method must yield conclusive and definite results (precluding false positive). Today, the new solid phase GC-FTIR hyphenated systems coupling gas chromatography (for separation/detection), and solid phase infrared spectroscopy (for detection), meet both requirements in one reliable and accurate instrument. In fact, the use of highly specific infrared spectroscopy2 reduces the risk of false positive identification by rapidly and accurately providing detailed structural information such as isomeric differences.
Detailed structural information is becoming invaluable for forensic analysts as they are increasingly confronted to new recreational synthetic drugs such as the JWH series with numerous “legal or not” potent analogs. Numerous so-called “research labs” have popped up to manufacture these “soon-to-be banned” analogs and take advantage of the current loopholes in the U.S. legislation on controlled substances. In particular, the interpretation of the term “substantially similar” in section A(i) is not specific enough to give a definite answer as to whether an analog of a controlled substance falls under the federal analog act3 or not, forcing legislators into a potential cat and mouse game with the manufacturers of designer drugs.4,5 In addition, if the manufacturers make sure to indicate that the drug is not for human consumption, then all bets are off.
Increasingly, forensic scientists are forced to deal with this problem by accurately identifying controlled substances and their analogs to support the court system. This application note will provide examples of the use of Direct Deposition GC-FTIR technology in the forensics environment, including demonstration of the Direct Deposition GC-FTIR instrument’s unique ability to deal with large volumes of samples, while highlighting the specificity of the technology by differentiating typical street drug isomers.
Methods of Analysis and Identification of Controlled Substances Categories of Analytical Techniques
The SWGDRUG requires the use of multiple independent identification techniques. They have divided currently-used methods into three categories, with “category A” techniques providing the best discriminating power.