High-sensitivity method for the determination of LSD and 2-oxo-3-hydroxy-LSD in oral fluid by liquid chromatography‒tandem mass spectrometry.

Abstract

We have developed and validated a high-sensitivity method to quantify lysergic acid diethylamide (LSD) and 2-oxo-3-hydroxy-LSD (OH-LSD) in oral fluid samples using liquid-liquid extraction and liquid chromatography-tandem mass spectrometry (LC‒MS/MS). The method was applied to the quantification of both substances in 42 authentic oral fluid samples. A liquid-liquid extraction was performed using 500 µL each of samples (oral fluid samples collected using Quantisal™ device) and dichloromethane/isopropanol mixture (1:1, v/v). Enzymatic hydrolysis was evaluated to cleave glucuronide metabolites. The limit of quantification was 0.01ng/mL for both LSD and OH-LSD. The linearity was assessed between 0.01 and 5ng/mL. Imprecision and bias were not higher than 10.2% for both analytes. Extraction recovery was higher than 69%. The analytes were stable in the autosampler at 10°C for 24h, and up to 30days at 4 and -20°C. The method was applied to the analysis of 42 oral fluid samples. LSD was detected in all samples (concentrations between 0.02 and 175ng/mL), and OH-LSD was detected in 20 samples (concentrations between 0.01 and 1.53ng/mL). A high-sensitive method was fully validated and applied to authentic samples. To our knowledge, this is the first work to report concentrations of LSD and OH-LSD in authentic oral fluid samples.