ACQUITY UPLC I-Class/Xevo TQ-S micro IVD System: Analytical Performance for a Mineralocorticoid

Significance of the Topic

Accurate quantification of aldosterone in plasma is critical for diagnosing and monitoring disorders of the renin–angiotensin–aldosterone system. Sensitive and precise measurement of this mineralocorticoid supports clinical decision making in hypertension, adrenal dysfunction and cardiovascular research.

Objectives and Study Overview

This study evaluated the analytical performance of the Waters ACQUITY UPLC I-Class/Xevo TQ-S micro IVD System for measuring aldosterone levels in human plasma. The goal was to assess sensitivity, precision and repeatability under routine in vitro diagnostic conditions.

Methodology and Instrumentation

Sample Preparation and Calibration
• Plasma calibrators and quality controls were prepared by spiking stripped serum with certified aldosterone reference material.
• A 200 µL aliquot of each sample was treated with zinc sulfate/methanol, diluted and centrifuged.
• Extracts were processed on Oasis MAX µElution plates, washed and eluted prior to injection.

Liquid Chromatography Conditions
• Column: CORTECS UPLC C18, 1.6 µm, 2.1 mm×100 mm
• Mobile Phases: A=water, B=methanol
• Flow Rate: 0.4 mL/min; Gradient: 40% B→60% B over 1 min, hold, then ramp to 95% B.

Mass Spectrometry Conditions
• System: Xevo TQ-S micro IVD with negative electrospray ionization
• Acquisition: Multiple reaction monitoring (MRM) of m/z 359.2→189.2
• Resolution: MS1 at 0.75 FWHM, MS2 at 0.5 FWHM
• Control Software: MassLynx IVD v4.1; Data Processing: TargetLynx Application Manager

Main Results and Discussion

The method demonstrated a linear calibration range of 42–4 161 pmol/L (r2>0.99). The lower limit of quantification (LLOQ) was established at 42 pmol/L with a signal-to-noise ratio >10. Total precision over five days at multiple QC levels was ≤7.2% and repeatability ≤7.0%. Chromatographic peaks consistently displayed peak-to-peak S/N ratios above 20 at or near the LLOQ.

Benefits and Practical Applications

• High sensitivity and low LLOQ facilitate reliable detection of low aldosterone concentrations.
• Robust precision and repeatability support routine clinical and research workflows.
• Automated sample processing and data handling increase throughput and reduce operator variability.

Future Trends and Opportunities

Advances in IVD-certified LC-MS/MS platforms will expand multiplexed steroid profiling in clinical laboratories. Ongoing improvements in column technology, ion source design and software-driven automation promise even greater sensitivity, shorter cycle times and wider analyte panels. Integration with cloud-based data analytics will enhance quality control and method standardization across laboratories.

Conclusion

The Waters ACQUITY UPLC I-Class/Xevo TQ-S micro IVD System provides a highly sensitive, precise and reproducible LC-MS/MS method for plasma aldosterone analysis, meeting requirements for clinical research and diagnostic applications.