Separating the wheat from the chaff: observations on the analysis of lysergamides LSD, MIPLA, and LAMPA

Abstract

Lysergic acid diethylamide (LSD) is a potent psychoactive substance that has attracted great interest in clinical research. As the pharmacological exploration of LSD analogs continues to grow, some of those analogs have appeared on the street market. Given that LSD analogs are uncontrolled in many jurisdictions it is important that these analogs can be differentiated from LSD. This report presents the analysis of blotters found to contain the N-methyl-N-isopropyl isomer of LSD (MIPLA), and techniques to differentiate it from LSD and the N-methyl-N-propyl isomer (LAMPA) under routine conditions. Gas chromatography (GC) - solid phase infrared spectroscopy was particularly helpful. GC electron ionization tandem mass spectrometry of the m/z 72 iminium ion also provided sufficient information to distinguish the three isomers on mass spectral grounds alone, where chromatographic separation proved challenging. Derivatization with 2,2,2-trifluoro-N,N-bis(trimethylsilyl)acetamide (BSTFA) also led to improved GC separation. Liquid chromatography single quadrupole mass spectrometry (LC-Q-MS) and in-source collision-induced dissociation allowed for the differentiation between MIPLA and LAMPA based on distinct m/z 239 ion ratios when co-eluting. An alternative LC- MS/MS method improved the separation between all three lysergamides but LSD was found to co-elute with iso-LSD. However, a comparison of ion ratios recorded for transitions at m/z 324.2 > 223.2 and m/z 324.2 > 208.2 facilitated their differentiation. The analysis of two blotters by LC-Q-MS revealed the presence of 180 μg and 186 μg MIPLA per blotter. These procedures may be used to avoid inadvertently misidentifying MIPLA or LAMPA as LSD