Simultaneous LC-MS/MS Analysis of Aldosterone and Plasma Renin Activity Using the Xevo™ TQ Absolute Mass Spectrometer for Clinical Research

Significance of the Topic

The renin-angiotensin-aldosterone system is central to blood pressure regulation and fluid balance. Precise quantification of aldosterone and plasma renin activity is essential in evaluating cardiovascular therapies and diagnosing endocrine disorders.

Objectives and Study Overview

This study aimed to develop and validate a single liquid chromatography–tandem mass spectrometry method to measure both aldosterone and plasma renin activity simultaneously. The approach targets improved throughput, reduced sample volume, and cost-effectiveness for clinical research applications.

Methodology

Calibrators and quality controls were prepared in bovine serum albumin and human plasma over clinically relevant ranges. Plasma samples (125 µL) underwent thawing, dilution, and a 3-hour incubation to generate angiotensin I for renin activity measurement. Internal standards were added prior to solid-phase extraction on an Oasis MAX µElution plate. Sequential washing and elution steps recovered aldosterone and angiotensin I for analysis. Chromatographic separation was achieved on a XBridge Premier Peptide BEH C18 column with a 3.2-minute gradient. Mass spectrometric detection employed multiple reaction monitoring with polarity switching.

Instrumentation

• ACQUITY UPLC I-Class FL System
• Xevo TQ Absolute Triple Quadrupole Mass Spectrometer
• Oasis MAX 96-well µElution Plate
• XBridge Premier Peptide BEH C18 Column (2.1×50 mm, 2.5 µm)

Main Results and Discussion

Aldosterone and angiotensin I eluted within two minutes with negligible carryover (<20% of lowest calibrator). The method demonstrated linearity (r2>0.995) across target ranges, with lower limits of quantification of 28 pmol/L for aldosterone and 0.08 nmol/L/hr for renin activity. Precision was excellent (CV≤6.8% for standards; ≤7.5% for controls). Matrix effects were minimal, with internal standards compensating ion suppression. Comparison with external quality assurance samples showed a Deming fit of y=0.93x+2.14 and mean bias of –6.1% for aldosterone. Method comparisons yielded biases of –6.0% (aldosterone) and +21.4% (renin activity). Equivalent performance was observed using argon or nitrogen collision gas.

Benefits and Practical Applications

• Single, multiplexed assay reduces analysis time and consumables
• High sensitivity enables measurement at physiologically low concentrations with minimal sample volume
• Automation-friendly extraction workflow supports high throughput

Future Trends and Opportunities

Integration of additional steroid and peptide biomarkers into multiplexed panels may enhance pathophysiological insights. Advances in ultra-high-throughput LC-MS/MS platforms, novel ionization strategies, and data analytics will further improve sensitivity, speed, and clinical applicability. Personalized medicine approaches may leverage such methods for tailored therapy monitoring.

Conclusion

The described LC-MS/MS method using the Xevo TQ Absolute system enables simultaneous, precise, and sensitive quantification of aldosterone and plasma renin activity in a single run. It offers robust performance, high throughput, and flexibility in collision gas selection, making it well suited for clinical research and biomarker studies.

References

Foley D, Calton LJ. Simultaneous LC-MS/MS Analysis of Aldosterone and Plasma Renin Activity Using the Xevo TQ Absolute Mass Spectrometer for Clinical Research. Waters Corporation; 2023.