Evaluation of Benchtop Quadrupole Orbitrap Ultra-High-Resolution Mass Spectrometer in Rapid Quantitative Analysis of Immunosuppressant Drugs in Blood Samples

Importance of the Topic

The precise and rapid quantification of immunosuppressant drugs in whole blood is critical for therapeutic drug monitoring and clinical research. These agents have narrow therapeutic windows and significant inter‐patient variability. Implementing a fast, robust method enhances patient safety and supports high‐throughput laboratory workflows.

Objectives and Overview of the Study

This work evaluates a benchtop quadrupole‐Orbitrap mass spectrometer for the quantitation of cyclosporin A, everolimus, sirolimus and tacrolimus in human whole blood. Key aims include method speed, specificity, precision, accuracy, matrix effect assessment and cross‐method correlation with a conventional triple quadrupole LC‐MS approach.

Methodology and Used Instrumentation

• Sample Preparation: 100 µL blood precipitated with 400 µL solvent containing ZnSO₄, internal standards (ascomycin, cyclosporin D), vortex, cool, centrifuge; supernatant injected.
• Liquid Chromatography: 3 min gradient on Thermo Dionex UltiMate 3000, Javelin guard column (10 × 2.1 mm, 5 µm), 75 °C, flow 0.5 mL/min; mobile phases: A (0.1% formic acid, 10 mM ammonium formate in water), B (same in methanol), C (acetonitrile/isopropanol/acetone).
• Mass Spectrometry: Thermo Q Exactive Focus Orbitrap with HESI source; PRM acquisition; resolution 17 500; isolation width 1 amu.
• Data Analysis: TraceFinder software for quantitation using the most abundant MS/MS fragment.

Main Results and Discussion

Limits of quantitation ranged from 2.3 to 26.1 ng/mL. Intra‐ and inter‐assay precision (RSD) were below 6%, and accuracy was within ±15%. Absolute recoveries from matrix spiking were 90–112%, and relative internal standard corrections yielded 80–99% recoveries. System robustness showed RSD < 5% across calibration standards. Cross‐correlation with a triple quadrupole method demonstrated strong agreement, supporting method validity.

Benefits and Practical Applications of the Method

• Rapid 3 min analysis allows high throughput.
• High‐resolution Orbitrap delivers clean chromatograms and improved selectivity.
• Cost‐efficient workflow with simple protein precipitation.
• Meets clinical research criteria for therapeutic drug monitoring.

Future Trends and Applications

Expansion to broader immunosuppressant panels, integration of automated sample preparation, adoption of high‐resolution workflows in routine clinical labs, and application of machine learning for spectral interpretation and quality control are anticipated.

Conclusion

A fast, precise and robust Orbitrap‐based LC‐MS method has been established for immunosuppressant quantitation in blood, offering significant advantages over conventional triple quadrupole systems and fulfilling clinical research requirements.

Reference

No specific literature references were provided in the source document.