Liquid chromatography-tandem mass spectrometry method for the simultaneous analysis of multiple hallucinogens, chlorpheniramine, ketamine, ritalinic acid, and metabolites, in urine.

A method for simultaneously measuring multiple hallucinogens, chlorpheniramine, ketamine, ritalinic acid, and several metabolites in human urine was developed and validated. The procedure uses solid-phase extraction followed by liquid chromatography-tandem mass spectrometry, with all drugs eluting within 14 minutes. Using 500 microliters of urine, limits of quantification ranged from 0.05 ng/mL for LSD to 10 ng/mL for other hallucinogens, with linear or quadratic regression from each compound's limit up to 500 ng/mL. Precision and accuracy were acceptable, and processed samples remained stable in the autosampler for at least 24 hours. The method was successfully applied to authentic urine samples containing chlorpheniramine, ketamine, LSD, and psilocin.

Study at a glance

Abstract

A validated method for the simultaneous analysis of multiple hallucinogens, chlorpheniramine, ketamine, ritalinic acid, and several metabolites is presented. The procedure comprises a sample clean-up step, using mixed-mode solid-phase extraction followed by liquid chromatography (LC)-tandem mass spectrometry analysis. Chromatographic separation was achieved using a Sunfire C(8) column eluted with a mixture of formate buffer, methanol, and acetonitrile. The applied LC gradient ensured the elution of all the drugs examined within 14 min and produced chromatographic peaks of acceptable symmetry. Selectivity of the method was achieved by a combination of retention time and two precursor-product ion transitions for the non-deuterated analogues. Validation of the method was performed using 500 microL of urine. The limits of quantification (LOQ) for LSD and 2-oxo-3-hydroxy-LSD were 0.05 and 1 ng/mL, respectively, and ranged, for the other hallucinogens, from 0.5 to 10 ng/mL. Linear and quadratic regression was observed from the LOQ of each compound to 12.5 ng/mL for LSD, 50 ng/mL for 2-oxo-3-hydroxy-LSD and 500 ng/mL for the others (r(2) > 0.99). Precision for the QC samples, spiked at a minimum of two concentrations, was calculated [%CV and %bias 87% for all the analytes. Furthermore, the processed samples were demonstrated to be stable in the autosampler for at least 24 h. Finally, the validated method was applied to the determination of chlorpheniramine, ketamine, LSD, and psilocin in authentic urine samples.