High-Sensitivity Analysis of Cortisol in Human Blood Serum Using LCMS-8060NX Triple Quadrupole Mass Spectrometer

Significance of the Topic

Cortisol quantification in human serum is critical for diagnosing adrenal and pituitary function and monitoring metabolic and inflammatory conditions.

Aims and Study Overview

This study demonstrates a high-sensitivity LC/MS/MS method using Shimadzu LCMS-8060NX for quantifying cortisol at picogram-per-milliliter levels in human blood serum.

Methodology and Sample Preparation

• Reference standard serial dilutions (2.5–100000 pg/mL) in 50% methanol.
• SPE cleanup using EVOLUTE EXPRESS ABN plates with acidified serum loading, multi-step washing, and elution.
• Reconstitution in 50% methanol.

Used Instrumentation

• Shimadzu Nexera X3 HPLC with Shim-pack Scepter C18 column (50×2.1 mm, 3 μm).
• LCMS-8060NX triple quadrupole with IonFocus™ interface, ESI positive mode.

Analysis Conditions

• Mobile phases: 0.2 mM NH4F in water and methanol with gradient from 50% to 95% B.
• Flow rate: 0.3 mL/min; injection volume: 2 μL.
• MRM transitions: cortisol (363.0→121.1) and internal standard D4 (367.1→121.1).

Main Results and Discussion

Linearity was excellent (R2 > 0.999) across 2.5–100000 pg/mL with accuracy within 80–110%. The limit of quantitation reached 2.5 pg/mL with clear MRM peaks. Spiked desteroidized serum yielded 92 pg/mL at a 100 pg/mL spike, confirming method accuracy.

Benefits and Practical Applications

• Ultra-sensitive cortisol detection for clinical and research settings.
• Reduced MS contamination via IonFocus, enhancing instrument robustness.
• Comprehensive workflow including sample preparation and analysis.

Future Trends and Potential Applications

Integration with automated sample preparation, expansion to multiplex steroid profiling, and adaptation to point-of-care platforms may further enhance clinical relevance and throughput.

Conclusion

The LCMS-8060NX method enables reliable quantification of cortisol down to 2.5 pg/mL in human serum with high selectivity and robustness, representing a valuable tool for endocrinology and biomarker research.