Dispersive liquid-liquid microextraction, an effective tool for the determination of synthetic cannabinoids in oral fluid by liquid chromatography-tandem mass spectrometry.

Journal: Journal of pharmaceutical analysis
Published Date: Nov 19, 2020

Abstract

In the present work, dispersive liquid-liquid microextraction (DLLME) was used to extract six synthetic cannabinoids (JWH-018, JWH-019, JWH-073, JWH-200, or WIN 55,225, JWH-250, and AM-694) from oral fluids. A rapid baseline separation of the analytes was achieved on a bidentate octadecyl silica hydride phase (Cogent Bidentate C; 4.6 mm × 250 mm, 4 μm) maintained at 37 °C, by eluting in isocratic conditions (water:acetonitrile (25:75, )). Detection was performed using positive electrospray ionization-tandem mass spectrometry. The parameters affecting DLLME (pH and ionic strength of the aqueous phase, type and volume of the extractant and dispersive solvent, vortex and centrifugation time) were optimized for maximizing yields. In particular, using 0.5 mL of oral fluid, acetonitrile (1 mL), was identified as the best option, both as a solvent to precipitate proteins and as a dispersing solvent in the DLLME procedure. To select an extraction solvent, a low transition temperature mixture (LTTM; composed of sesamol and chlorine chloride with a molar ratio of 1:3) and dichloromethane were compared; the latter (100 μL) was proved to be a better extractant, with recoveries ranging from 73% to 101 % by vortexing for 2 min. The method was validated according to the guidelines of Food and Drug Administration bioanalytical methods: intra-day and inter-day precisions ranged between 4 % and 18 % depending on the spike level and analyte; limits of detection spanned from 2 to 18 ng/mL; matrix-matched calibration curves were characterized by determination coefficients greater than 0.9914. Finally, the extraction procedure was compared with previous methods and with innovative techniques, presenting superior reliability, rapidity, simplicity, inexpensiveness, and efficiency.

Authors

  • Pierpaolo Tomai
    Department of Chemistry, Sapienza University, P.le Aldo Moro 5, 00185, Rome, Italy.
  • Alessandra Gentili
    Department of Chemistry, Sapienza University, P.le Aldo Moro 5, 00185, Rome, Italy.
  • Roberta Curini
    Department of Chemistry, Sapienza University, P.le Aldo Moro 5, 00185, Rome, Italy.
  • Rossella Gottardo
    Department of Diagnostics and Public Health, University of Verona, Verona, Italy and Institute of Translational Medicine and Biotechnology, Sechenov First Moscow State Medical University, Moscow, Russia.
  • Franco Tagliaro
    Department of Diagnostics and Public Health, University of Verona, Verona, Italy and Institute of Translational Medicine and Biotechnology, Sechenov First Moscow State Medical University, Moscow, Russia.
  • Salvatore Fanali
    Teaching Committee of Ph.D. School in Natural Science and Engineering University of Verona, Verona, Italy.

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