Simultaneous Analysis of Etizolam, Triazolam, and Their Metabolites in Biospecimens Using LCMS™-9030

Significance of the Topic

Etizolam and triazolam belong to the benzodiazepine class of psychotropic drugs widely used as sedatives, hypnotics, anxiolytics, anticonvulsants, and muscle relaxants. Their metabolites in biological specimens are critical targets in forensic toxicology, driving the need for robust and reliable analytical methods such as high-resolution liquid chromatography-mass spectrometry (LC-MS).

Objectives and Study Overview

This study aimed to develop and validate a simultaneous analytical protocol for etizolam, triazolam, and their primary hydroxylated metabolites (α-hydroxyetizolam, α-hydroxytriazolam, and 4-hydroxytriazolam) in human whole blood and plasma using ultra-high-performance liquid chromatography (UHPLC) coupled to a quadrupole time-of-flight (Q-TOF) mass spectrometer.

Methodology and Instrumentation

Pretreatment:

• QuEChERS extraction: 100 µL biospecimen, 300 µL acetonitrile, Q-sep salt packet, water, steel beads, centrifugation at 10 000 rpm for 10 min.
• Supernatant collected for LC-MS analysis; standards spiked at 10 ng/mL for recovery tests.

Chromatography:

• UHPLC system: Shimadzu Nexera X2.
• Column: YMC-Triart C18, 1.9 µm, 50 × 2 mm, 40 °C.
• Mobile phases: A = 0.1 % formic acid in water; B = 0.1 % formic acid in acetonitrile.
• Gradient: 20 % B (0 min), 20 % (3 min), 30 % (11.5 min), 95 % (11.51–13 min), return to 20 % B (13.01 min), stop at 15 min; flow rate 0.6 mL/min; injection volume 2 µL.

Mass Spectrometry:

• High-resolution Q-TOF: Shimadzu LCMS-9030.
• Ionization: ESI positive; interface 300 °C; DL 250 °C; heat block 400 °C.
• Gas flows: nebulizer 3.0 L/min; heating 10.0 L/min; drying 5.0 L/min.

Main Results and Discussion

Separation and Detection:

• Etizolam and triazolam (Δm/z = 26 mDa) were resolved chromatographically.
• α-Hydroxy metabolites coeluted but were distinguished by accurate mass extraction windows (±2 mDa).

Linearity and Sensitivity:

• Calibration curves over 1–100 ng/mL exhibited excellent linearity (R² ≥ 0.999).
• Limits of detection allowed quantification at 10 ng/mL with clear signal in spiked matrices.

Accuracy and Precision:

• Spike-and-recovery in whole blood: 105–115 % accuracy at 10 ng/mL.
• Spike-and-recovery in plasma: 117–131 % accuracy at 10 ng/mL.
• Mass errors remained within ±0.354 mDa across concentrations and matrices, demonstrating stable mass accuracy.

Benefits and Practical Applications

The high mass resolution of the Q-TOF instrument enables selective quantification of isobaric metabolites without extensive chromatographic separation. The fast UHPLC gradient (15 min runtime) and minimal sample preparation make this workflow suitable for high-throughput forensic and clinical toxicology laboratories.

Future Trends and Potential Applications

• Extension to additional benzodiazepine analogs and their glucuronide or sulfate conjugates.
• Integration of automated sample preparation and online extraction to increase throughput.
• Application of data-dependent acquisition or MS/MS spectral libraries for structural confirmation.
• Adoption of microflow or nano-LC to reduce solvent consumption and enhance sensitivity.

Conclusion

The developed UHPLC-Q-TOF method provides rapid, accurate, and reproducible simultaneous analysis of etizolam, triazolam, and their hydroxylated metabolites in biospecimens. Its high sensitivity, mass accuracy, and robust quantitation make it a powerful tool for forensic toxicology and clinical research.

Reference

Not applicable