MSACL 2019 EU Abstract

Ultra-low Level Analysis of Aldosterone in Plasma Using the Xevo TQ-XS for Clinical Research

Dominic Foley, Gareth Hammond, Ben Dugas, Lisa J Calton
Waters Corporation, Stamford Avenue, Altrincham Road, Wilmslow, SK9 4AX, UK

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Ben Dugas (Presenter) Waters Corporation

Relevant Financial Disclosures (within past 24 months) Grant/Research Support Waters Corporation Conflict mitigation NOT REQUIRED.

Background: Aldosterone is a mineralocorticoid steroid hormone that plays a key role in the regulation of blood pressure. We developed a LC-MS/MS method for the measurement of plasma aldosterone for clinical research purposes. An analytically sensitive method was developed using a mixed-mode Solid Phase Extraction (SPE) sorbent in 96-well plate format. Automated extraction was employed, enabling high throughput of samples. Samples were injected onto an ACQUITY UPLC™ I-Class system with separation on a Waters™ CORTECS™ C18 2.7µm column with VanGuard™ precolumn using an ammonium fluoride(aq)/methanol gradient. Detection was performed using a Waters Xevo™ TQ-XS mass spectrometer to help quantify very low physiological concentrations of aldosterone.
Methods: Aldosterone certified reference material purchased from Cerilliant (Round Rock, TX) was used to create calibrators in stripped pooled serum purchased from Golden West Biologicals (Temecula, CA). QC material was prepared in K2EDTA plasma purchased from SeraLab (Haywards Heath, UK). EQA samples from NEQAS (Birmingham, UK) were analysed to evaluate analytical method bias. 200µL samples were pre-treated with zinc sulphate in methanol, followed by dilution with water. SPE was carried out with a Waters Oasis™ MAX µElution 96 well plate to reduce ion suppression and concentrate the samples without the need for evaporation. Automated extraction was performed using the Tecan Freedom Evo 100/4 Liquid Handler. Using an ACQUITY UPLC I-Class system, samples were injected onto a CORTECS C18 2.7µm 2.1 x 100 mm column with VanGuard™ precolumn using a 0.05mM ammonium fluoride(aq)/methanol gradient elution profile and quantified with a Waters Xevo TQ-XS mass spectrometer.
Results: The method demonstrated no significant carryover or matrix effects and was shown to be linear from 3 – 1500 pg/mL for aldosterone. Analytical sensitivity investigations indicate the analytical sensitivity of this method would allow precise quantification (<20%) at 3 pg/mL with a S/N (PtP) > 10. Coefficients of variation (CV) for total precision and repeatability on 5 occasions for low (13 pg/mL), mid (103pg/mL) and high (1057 pg/mL) QC material were all ≤6.3% (n = 25) for aldosterone using automated extraction. Analysis of EQA samples (n=15) demonstrated a mean bias of -3.2% compared to the EQA MS laboratory mean for the samples.
Conclusions: We have successfully quantified aldosterone in plasma using an automated SPE protocol with LC-MS/MS analysis, for clinical research purposes. The method demonstrates excellent sensitivity, linearity, precision and bias with minimal matrix effects.
For Research Use Only. Not for use in diagnostic procedures.