A Method for Identification of Lysergic Acid Diethylamide (LSD) Using a Microscope Sampling Device with Fourier Transform Infrared (FT/IR) Spectroscopy

The identification of lysergic acid diethylamide (LSD) has posed an analytical challenge for forensic science laboratories. In those cases in which a few doses are seized, only microgram quantities are available, often in forms which make isolation of the miniscule amount of LSD difficult. A method is described which yields small crystals of pure LSD in a form well-suited for analysis using a microscope sampling device with a Fourier transform infrared (FT/IR) spectrometer. These crystals produce excellent spectra from samples containing less than 50 µg of LSD. Distinguishing between LSD, iso-LSD, and lysergic acid N-methylpropylamide (LAMPA) poses no problem with the spectra obtained. This scheme combines preparative thin-layer chromatography (TLC) followed by wick evaporation, an old but not well-known technique for separating soluble components from high-solid mixtures without filtration.