Identification of closely related new psychoactive substances (NPS) using solid deposition gas-chromatography infra-red detection (GC-IRD) spectroscopy.

The challenges associated with the identification of new NPS have become more apparent with the increasing number of new drugs in the market and the need to identify the specific isomer due to legislation concomitant with the lack of reference standards for comparison. A recent new tandem technique, solid deposition gas chromatography-infra red detection spectroscopy (GC-IRD), which incorporates the GC for the separation of the different components in the sample matrix and infrared red (IR) spectroscopy which provides unique IR spectra of each component, has provided the necessary discrimination for the identification of isomers. This paper presents the identification and the application of an algorithm-based criteria (ABC) for the evaluation of the quality match factor (QMF) as an objective critical criteria in determining the correctness of an identification of close analogues in four classes of compounds; namely the JWH-018 and its structural isomers, AM-2201 and its fluoro positional isomers in the pentyl group, methylmethcathinone (MMC) and its methyl positional isomers in the phenyl ring, and dibutylone and its close analogues.