The Determination of Lysergide (LSD) in Urine by High-Performance Liquid Chromatography-Isotope Dilution Mass Spectrometry (IDMS)

Isotope dilution mass spectrometry (IDMS) improves the forensic confirmation of lysergic acid diethylamide (LSD) in urine when using liquid chromatography–mass spectrometry (LC-MS). Using a deuterated analog of LSD as an internal standard offers advantages over methysergide. The method achieves a limit of quantification (LOQ) of 0.5 ng/mL, meeting the laboratory's forensic requirement, and can be improved to 0.1 ng/mL under some circumstances. It is linear up to 10 ng/mL LSD in urine and has been validated for accuracy and precision. The study also compares electrospray mass spectra of LSD, LSD-d3, and methysergide, and discusses suitable ions for selected ion monitoring.

Study at a glance

Abstract

Abstract The use of isotope dilution mass spectrometry (IDMS) has been investigated for the forensic confirmation of lysergic acid diethylamide (LSD) in urine by LC-MS. The advantages of using a deuterated analog of LSD as an internal standard over methysergide are discussed. This study includes a comparison of the electrospray mass spectra of LSD, LSD-d3 and methysergide, and discusses the choice of suitable ions for use in selected ion monitoring (SIM) mode. An IDMS method is presented for the LC-MS confirmation of LSD in urine, with a limit of quantification (LOQ) of 0.5 ng/mL, reflecting the forensic requirement at this laboratory. Under some circumstances the LOQ can be improved to 0.1 ng/mL. This method is linear in the range tested (up to 10 ng/mL LSD in urine) and has been validated in terms of accuracy and precision.