A precise, sensitive and stable LC-MSMS method for detection of picomolar levels of serum aldosterone. (4th July 2018)

• Record Type: Journal Article
• Authors: Lie, Margrete; Thorstensen, Ketil
• Is Part Of: Scandinavian journal of clinical & laboratory investigation. Volume 78:Number 5(2018)
• Page Start: 379
• Page End: 385
• Publication Date: 2018-07-04
• Subjects: Chromatography -- steroid hormones -- aldosteronism -- ESI-positive mode; Clinical biochemistry -- Periodicals; Physiology, Pathological -- Periodicals; Physiology, Experimental -- Periodicals; Medicine -- Research -- Periodicals; Clinical medicine -- Periodicals; 616.0072
• DOI: 10.1080/00365513.2018.1480060
• Languages: English
• ISSNs: 0036-5513

Abstract

Abstract: Background: Accurate quantification of aldosterone is essential in the diagnosis of primary aldosteronism. Liquid chromatography-tandem mass spectrometry (LC-MSMS) analysis is increasingly being used to improve analytical sensitivity and specificity, since this technology reduces most of the interferences observed with immunological methods. Methods: Serum samples with d7 -aldosterone as internal standard were extracted with methyl tert-butyl ether, using liquid-liquid extraction (LLE). Chromatographic separation was performed on a C18 reverse phase column with a methanol-water gradient containing ammonium fluoride. Aldosterone detection was performed on an Agilent 6490 triple quadrupole using electro spray ionisation in positive mode. Results: Multiple reaction monitoring transitions were m/z 361.2–315.1 for aldosterone, and 368.5–323.3 for d7 -aldosterone. Chromatographic retention time was 2.7 min. The method's total CVs at aldosterone concentrations of 45.4 and 1080 pmol/L were 7.0% and 4.8%, respectively. The intra-assay CVs at concentrations of 60.0 and 637 pmol/L were 4.0% and 2.6%, respectively. The method's LOQ and LOD were 10 and 5 pmol/L, respectively, demonstrating an excellent analytical sensitivity. The upper limit of quantification was set to 5000 pmol/L, corresponding to the highest calibrator concentration. The long-term stability of the method was evident from repeated measurements of external control pools from UKNEQAS over a period of about 3 years, showing CVs between 2.0 and 7.0%. Conclusions: We have described a precise, sensitive and stable LC-MSMS method for the measurement of serum aldosterone. In addition, due to the use of LLE and a short LC-column, the method is simple to perform, with a short chromatographic run time.