Anal. Chem., 76 (23), 7143 -7148, 2004. 10.1021/ac049285e S0003-2700(04)09285-6
Web Release Date: October 15, 2004

Published 2004 American Chemical Society

Quantitation of Lysergic Acid Diethylamide in Urine Using Atmospheric Pressure Matrix-Assisted Laser Desorption/Ionization Ion Trap Mass Spectrometry

Meng Cui,* Margaret A. McCooeye, Catharine Fraser, and Zoltán Mester

Institute for National Measurement Standards, National Research Council of Canada, Ottawa K1A 0R6, Canada

Received for review May 15, 2004. Accepted August 26, 2004.

Abstract:

A quantitative method was developed for analysis of lysergic acid diethylamide (LSD) in urine using atmospheric pressure matrix-assisted laser desorption/ionization ion trap mass spectrometry (AP MALDI-ITMS). Following solid-phase extraction of LSD from urine samples, extracts were analyzed by AP MALDI-ITMS. The identity of LSD was confirmed by fragmentation of the [M + H]+ ion using tandem mass spectrometry. The quantification of LSD was achieved using stable-isotope-labeled LSD (LSD-d3) as the internal standard. The [M + H]+ ion fragmented to produce a dominant fragment ion, which was used for a selected reaction monitoring (SRM) method for quantitative analysis of LSD. SRM was compared with selected ion monitoring and produced a wider linear range and lower limit of quantification. For SRM analysis of samples of LSD spiked in urine, the calibration curve was linear in the range of 1-100 ng/mL with a coefficient of determination, r2, of 0.9917. This assay was used to determine LSD in urine samples and the AP MALDI-MS results were comparable to the HPLC/ ESI-MS results.

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