Development and validation of a modified QuEChERS method coupled with liquid chromatography-electrospray ionization-tandem mass spectrometry for simultaneous determination of z-drugs in biological matrices

Abstract

The objective of this study was to develop and validate a modified QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) method coupled with liquid chromatography-tandem mass spectrometry for the simultaneous determination of Z-Drugs (a class of sedative-hypnotic medications) in biological matrices include saliva and tissue sample. This study utilized a modified QuEChERS approach to determine the most optimal conditions for simultaneously measuring three non-benzodiazepines in saliva and tissue samples through Liquid Chromatography with Tandem Mass Spectrometry. A fixed sample volume of 10 uL was injected, and the analytical column was consistently kept at 40°C. Various concentrations (5, 10, 20, 50, 100, and 200 ng/mL) were employed for analysis. The limit of quantification for all drugs ranged from 0.25 to 0.5 ng/mL. As a result, we have successfully extracted zolpidem, zopiclone, and eszopiclone from biological matrices for the first time, achieving a high recovery rate (> 90%). This extraction approach proves to be highly beneficial for obtaining these substances from various biological samples since it employs a significantly reduced amount of solvent, thus minimizing waste production.