Qualitative confirmation of 30 phencyclidine analogs in human blood and urine using GC-HRMS and a self-built library search

Abstract

Introduction

Phencyclidine, a dissociative anesthetic with hallucinogenic effects, is commonly abused as a recreational drug. Phencyclidine analogs are compounds produced by substitutions of the phenyl and piperidine rings of phencyclidine. Illegal use of phencyclidine and its analogs has symptoms such as addiction, confusion, and increased tendencies toward violence. In this study, a novel high-throughput screening method was applied for GC-HRMS identification of 30 phencyclidine analogs in human blood and urine. Methods: After a simple extraction with ethyl ether and buffer, followed by centrifugation, the supernatant was injected into the system. Analytes were identified using a self-built library and searching against reference spectra. Phencyclopiperidine analogs in the samples were identified, and isomers were differentiated using the exact molecular mass and retention time (RT) of the characteristic fragment ions. Results: The method was fully validated, no exogenous or endogenous interferences were observed, and recovery ranged from 30 % to 123 %. The more than 100 % recovery of DMXE, HXE, ketamine, and Cl-634 may be due to matrix-induced response enhancement. The limits of detection ranged from 0.05 to 5 ng/mL. The analytical method was successfully applied for separation of three groups of isomers: 2-FDCK and 4-FDCK; 3-MeO-PCP, 4-MeO-PCP and 4-MeOH-PCP; and PCMPA and PCEEA. This analytical approach was successfully applied for the identification of phencyclidine analogs in blood and urine samples from 800 authentic forensic cases. Four phencyclidine analogs were detected—2-F-2-oxo-PCE, 3-MeO-PCE, O-PCE, and 2-FDCK—demonstrating the method’s suitability for sensitive and fast high-throughput screening of drugs in human blood and urine samples.