Quantification of 36 antidepressants in human plasma by LC-HRAM-MS for clinical research

Significance of the topic

Therapeutic drug monitoring of antidepressants ensures optimal dosing, maximizes efficacy, and minimizes adverse effects. High-resolution accurate-mass mass spectrometry (HRAM-MS) provides the sensitivity and specificity needed for precise quantification in clinical research settings.

Objectives and overview

This study aimed to develop and validate a rapid LC-HRAM-MS method for the simultaneous quantification of 36 commonly prescribed antidepressants in human plasma. Key goals included assessing linearity, determining lower limits of quantitation, evaluating carryover, and measuring accuracy and precision using a comprehensive ClinMass sample preparation kit.

Methodology and instrumentation

Plasma aliquots (50 µL) were processed by protein precipitation with internal standard addition. Chromatographic separation occurred on a Vanquish Flex Binary UHPLC system using a 3.70 min gradient. Detection employed an Orbitrap Exploris 120 mass spectrometer with heated electrospray ionization in positive mode and data-dependent MS2 acquisition. Quantitation and data review were performed in TraceFinder 5.1 software.

Used instrumentation

• Thermo Scientific Vanquish Flex Binary UHPLC
• Thermo Scientific Orbitrap Exploris 120 MS with HESI source
• ClinMass TDM Platform and Antidepressants Add-On Set
• Thermo Scientific TraceFinder 5.1 software

Results and discussion

The method exhibited excellent linearity across analyte-specific calibration ranges, with R² values exceeding 0.996. LLOQs spanned from 0.231 to 161 µg/L. No notable carryover was detected. Accuracy bias for quality controls remained within ±10.3%, and both intra- and inter-assay precision stayed below 10.1% CV. Representative chromatograms at LLOQ and calibration curves confirmed reliable detection and quantification.

Benefits and practical applications

• Efficient offline protein precipitation workflow
• High throughput with sub-4-minute run times
• Robust sensitivity for therapeutic monitoring
• Broad analyte coverage supporting diverse clinical research

Future trends and opportunities

Advancements in automated sample preparation, expanded compound panels, and integration with machine learning–based data analysis will further enhance HRAM-MS utility in personalized psychiatry and large-scale pharmacokinetic studies.

Conclusion

A validated, high-performance LC-HRAM-MS assay for 36 antidepressants in plasma has been established, offering speed, simplicity, accuracy, and reproducibility to support clinical research and therapeutic drug monitoring.