Liquid Chromatography-Electrospray Ionization Mass Spectrometry for the Detection of Lysergide and a Major Metabolite, 2-Oxo-3-Hydroxy-LSD, in Urine and Blood

A method measures LSD and its metabolite O-H-LSD in urine and blood. O-H-LSD appears in urine at concentrations many times higher than LSD, extending detection time for confirming LSD use. A single-step liquid-liquid extraction on 5-mL urine samples precedes liquid chromatography with electrospray ionization mass spectrometry. Detection limits are 400 pg/mL for O-H-LSD and 100 pg/mL for LSD. In nine LSD-positive urine samples, mean O-H-LSD concentration was 6378 pg/mL (range 332-21371 pg/mL) and mean LSD concentration was 844 pg/mL (range 177-2456 pg/mL), with O-H-LSD levels 0.9 to 19.8 times higher than LSD (mean 10.2). No O-H-LSD was detected in blood samples. Enzymatic hydrolysis of six urine samples showed no significant difference, indicating absence of glucuronic acid conjugation.

Study at a glance

Abstract

A method is presented for the quantitative measurement of lysergide (LSD) and its metabolite 2-oxo-3-hydroxy-LSD (O-H-LSD) in urine and blood. O-H-LSD has been reported to have urinary concentrations many times higher than LSD. Measuring its presence in urine would significantly extend the detection time for confirming LSD abuse. A single-step liquid-liquid extraction was performed on 5-mL urine samples prior to separation by gradient liquid chromatography (LC). Electrospray ionization was used to produce the positively charged ions of O-H-LSD, 2-oxo-3-hydroxy-LAMPA (O-H-LAMPA, internal standard), LSD, and iso-LSD. Varying the orifice voltage in the intermediate-pressure region of the source generated the fragmentation necessary to produce qualifying ions. Selected ion monitoring allowed detection limits of 400 pg/mL and 100 pg/mL for O-H-LSD and LSD, respectively. The method was linear for O-H-LSD from 400 to 8000 pg/mL and for LSD from 100 to 6000 pg/mL. LSD-positive samples (n = 9) analyzed by the liquid chromatography-mass spectrometry method were found to contain mean concentrations of 6378 pg/mL O-H-LSD (332-21371 pg/mL) and 844 pg/mL LSD (177-2456 pg/mL). O-H-LSD urinary concentrations were between 0.9 and 19.8 times higher than LSD (mean = 10.2). Whole-blood samples were also analyzed following additional sample cleanup. LSD was measured in the blood samples, but no O-H-LSD was detected. Enzymatic hydrolysis was carried out on LSD-positive samples (n = 6) to evaluate the existence of conjugated O-H-LSD. Beta-glucuronidase from Helix pomatia was incubated with urine samples at 37 degrees C, pH 5.2 for 24 h. At an enzymatic activity of approximately 4000 units per milliliter of urine, no significant (p = 0.05) difference was seen between hydrolyzed and nonhydrolyzed samples suggesting an absence of O-H-LSD-glucuronic acid conjugation.