Mass-Spectrometry-Based Identification of Synthetic Drug Isomers Using Infrared Ion Spectroscopy

Abstract

Infrared ion spectroscopy (IRIS), a mass-spectrometry-based technique exploiting resonant infrared multiple photon dissociation (IRMPD), has been applied for the identification of novel psychoactive substances (NPS). Identification of the precise isomeric forms of NPS is of significant forensic relevance since legal controls are dependent on even minor molecular differences such as a single ring-substituent position. Using three isomers of fluoroamphetamine and two ring-isomers of both MDA and MDMA, we demonstrate the ability of IRIS to distinguish closely related NPS. Computationally predicted infrared (IR) spectra are shown to correspond with experimental spectra and could explain the molecular origins of their distinctive IR absorption bands. IRIS was then used to investigate a confiscated street sample containing two unknown substances. One substance could easily be identified by comparison to the IR spectra of reference standards. For the other substance, however, this approach proved inconclusive due to incomplete mass spectral databases as well as a lack of available reference compounds, two common analytical limitations resulting from the rapid development of NPS. Most excitingly, the second unknown substance could nevertheless be identified by using computationally predicted IR spectra of several potential candidate structures instead of their experimental reference spectra.

Performance evaluation of handheld Raman spectroscopy for cocaine detection in forensic case samples

“…However, in mixtures, which is often the case in actual cocaine case samples, 38,39 the observed Raman spectrum originates from all present substances, and spectral bands can overlap or obscure each other. This will compromise traditional library searching strategies similarly as other direct spectroscopic analyses (such as FTIR) that are—without prior separation—not well suited for mixture analysis 40 . As all substances yield both a different Raman signal intensity and different individual Raman peaks, it is evident that the instrument's performance, and detection range for cocaine varies per individual substance.…”

“…This will compromise traditional library searching strategies similarly as other direct spectroscopic analyses (such as FTIR) that are-without prior separation-not well suited for mixture analysis. 40 As all substances yield both a different Raman signal intensity and dif- PLS is a supervised chemometric approach requiring a binary variable for classification purposes (i.e., PLS-DA) or a numerical value for quantification (i.e., PLS-R). This study aims to develop a model to correctly classify case samples as either cocaine containing or cocaine negative.…”

Analytical Characterization of 3-MeO-PCP and 3-MMC in Seized Products and Biosamples: The Role of LC-HRAM-Orbitrap-MS and Solid Deposition GC-FTIR

“…MMC and MeO-PCP analogs may show quite similar chromatographic and, especially, mass spectrometric behaviors, which may hinder their full characterization in the case of unavailability of reference standards for all isomers, and/or their metabolites in case of biosample analysis. These analytical challenges have been addressed by several authors by means of different analytical approaches, for the discrimination of 2-MMC, 3-MMC, and 4-MMC ( Power et al, 2011 ; Power et al, 2012 ; Jamey et al, 2016 ; Maas et al, 2017 ; Zuba and Adamowicz, 2017 ; Nowak et al, 2018 ; Kranenburg et al, 2019 ; Kranenburg et al, 2020a ; Kranenburg et al, 2020b ) and 3-MeO-PCP and 4-MeO-PCP ( Bäckberg et al, 2015a ; Bakota et al, 2016 ; Bertol et al, 2017 ; Johansson et al, 2017 ; Mitchell-Mata et al, 2017 ; Zidkova et al, 2017 ; Ameline et al, 2019b ; Berar et al, 2019 ; de Jong et al, 2019 ; Kintz et al, 2019 ). However, such discriminative analyses were in most cases carried out with all the necessary reference standards available.…”

Application of mid-infrared free-electron laser for structural analysis of biological materials

“…Basically, the oscillation wavelengths are ranged from X-ray to the farinfrared region, and X-ray FELs are well employed for analyses of structural dynamics of proteins and time-resolved analysis of enzymatic reactions in pharmaceutical and biochemical fields (Ishchenko et al, 2019;Dasgupta et al, 2019). Although these FEL operation systems have been developed at several traditional facilities such as CLIO, FELIX, J-Lab, ELBE and SACLA (Cohn et al, 2015), the applicability of mid-infrared FELs (MIR-FELs) for the biorelated research fields is less recognized except for limited studies in pharmacy and surgical medicine (Auerhammer et al, 1999;Fraschetti et al, 2015;Kranenburg et al, 2020;Sakamoto et al, 2012;Edwards et al, 2005;Mackanos et al, 2005;Awazu et al, 1998). A remarkable feature of MIR-FELs is that the oscillation wavelengths are tunable within the mid-infrared region from $ 3.5 to 25 mm, and there are many wavelengths resonant with various functional groups of biomolecules in this fingerprint region (Bouchet et al, 2017;Ziegler et al, 2016).…”