A fast LC-APCI/MS method for analyzing benzodiazepines in whole blood using monolithic support

Area of Science:

• Analytical Chemistry
• Forensic Toxicology

Background:

• Benzodiazepines (BZDs) are widely prescribed, necessitating reliable quantification in biological matrices.
• Accurate determination of BZDs is critical in clinical and forensic toxicology, especially for low-dose or postmortem samples.

Purpose of the Study:

• To develop and validate a rapid, simultaneous method for quantifying eight benzodiazepines in whole blood.
• To compare atmospheric pressure chemical ionization (APCI) and electrospray ionization (ESI) for BZD analysis.

Main Methods:

• Simultaneous determination of eight benzodiazepines using liquid chromatography-atmospheric pressure chemical ionization-mass spectrometry (LC-APCI-MS).
• Sample preparation involved liquid-liquid extraction (LLE) with n-butylchloride.
• Chromatographic separation was achieved using a monolithic silica column for enhanced speed.

Main Results:

• The validated method achieved a limit of quantification (LOQ) of 2.5 microg/L for all eight benzodiazepines.
• Atmospheric pressure chemical ionization (APCI) demonstrated slightly higher sensitivity compared to electrospray ionization (ESI).
• Analysis of eight benzodiazepines was completed in under 5 minutes with high selectivity and accuracy.

Conclusions:

• A simple, fast, and validated LC-APCI-MS method allows for the simultaneous quantification of eight benzodiazepines in whole blood.
• The method is suitable for subtherapeutic quantification and analysis of benzodiazepines in postmortem blood samples.
• The use of monolithic silica columns and APCI contributes to the method's efficiency and sensitivity.