ABSTRACT
Aminoindanes are a class of novel psychoactive substances (NPSs) that have become more prevalent over the past decade. GC-MS is often utilized for identifying seized drugs and is well regarded for its ability to separate mixtures. However, certain aminoindanes have similar mass spectral data and require specific gas chromatographic stationary phases for separation. Derivatization is an alternative method that can be applied to GC-MS to enhance chromatographic results, providing more selective analysis in seized-drug identification. This study investigates derivatization techniques to provide options for forensic science laboratories in accurately identifying aminoindanes. Three derivatization reagents, N-methyl-bis(trifluoroacetamide) (MBTFA), heptafluorobutyric anhydride (HFBA), and ethyl chloroformate (ECF) were evaluated for the analysis of eight aminoindanes by GC-MS using two common gas chromatographic stationary phases, Rxi®-5Sil MS and Rxi®-1Sil MS. All three derivatization methods successfully isolated eight aminoindanes, including the isomers 4,5-methylenedioxy-2-aminoindane (4,5-MDAI), and 5,6-methylenedioxy-2-aminoindane (5,6-MDAI) that could not be differentiated prior to derivatization. Reduced peak tailing and increased abundance were observed after derivatization for all the compounds, and mass spectra of the derivatives contained individualizing fragment ions that allowed for further characterization of the aminoindanes. This excluded 4,5-MDAI and 5,6-MDAI as they shared the same characteristic ions and were only distinguishable by their retention times. All three derivatization techniques used in this study allow for successful characterization of the aminoindanes and give forensic science laboratories flexibility in their analysis approach when they encounter these compounds.
ABSTRACT
RATIONALE: Aminoindanes are one class of many new psychoactive substances that have emerged over the last decade. Analogues of 2-aminoindane (2-AI) are being encountered in crime laboratories and analytical data for most aminoindanes are limited. Interpretation and optimization of gas chromatography-mass spectrometry data will enhance reliability in characterizing aminoindanes. METHODS: This study focuses on the electron ionization mass spectrometric fragmentation of eight aminoindane analogues and the gas chromatographic separation of these eight aminoindane analogues using four different column stationary phases, Rxi®-1Sil MS, Rxi®-5Sil MS, Rxi®-35Sil MS, and Rxi®-624Sil MS. Split injection (25:1) was utilized and each column had the same configuration (30 m × 25 mm × 0.25 µm), with the exception of the Rxi®-624Sil MS column (30 m × 25 mm ×1.4 µm). RESULTS: Mass spectra showed strong molecular ions for all aminoindanes, except for rasagiline that produced a uniquely abundant [M - 1] ion. Other characteristic fragmentation that was present for all the aminoindanes included indane and indene ions (m/z 115-117), the tropylium ion (m/z 91), and subsequent loss of diene to produce smaller ions that followed: phenyl (m/z 77), cyclopentadienyl (m/z 65), cyclobutadienyl (m/z 51), and cyclopropenyl (m/z 39). CONCLUSIONS: Separation of eight aminoindanes was optimized, and linear retention indices were determined for the compounds on four capillary columns. Based on the retention data, all eight aminoindanes were resolved on an Rxi®-624Sil MS column. Each aminoindane exhibited unique fragmentation ions in the mass spectra to distinguish between similar analogues. The results of this study will strengthen the analytical profiles of 2-AI and seven analogues, assisting forensic scientists in their analysis and identification of these substances.
ABSTRACT
This article contains data from triplicate analyses of ten different TLC mobile phase systems from the analysis of 11 cannabinoid standards using HPTLC. The data includes 1) example plate images for 8 mobile phases during evaluation; 2) example table of calculated average, standard deviation, CV% of RF for hexane:acetone (87:13) system during evaluation; 3) images of all case sample plates. The validation of the two chosen mobile phases were done according to the SWGDRUG validation requirements [1]. This data can be used for choosing an alternative mobile phase TLC system for the analysis of cannabinoids. The data described in this article is related to a previous published research article "High Performance Thin-Layer Chromatography (HPTLC) analysis of cannabinoids in cannabis extracts" by Liu, et al. (2020) [2].