High-sensitivity method for the determination of LSD and 2-oxo-3-hydroxy-LSD in oral fluid by liquid chromatography‒tandem mass spectrometry.
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‒MSMS). 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 dichloromethaneisopropanol mixture (11, vv). Enzymatic hydrolysis was evaluated to cleave glucuronide metabolites. The limit of quantification was 0.01 ngmL for both LSD and OH-LSD. The linearity was assessed between 0.01 and 5 ngmL. 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 24 h, and up to 30 days 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 175 ngmL), and OH-LSD was detected in 20 samples (concentrations between 0.01 and 1.53 ngmL). 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.