Magnetic bead-assisted extraction combined with LC-MS/MS for simultaneous quantification of aldosterone and related...

The quantitative analysis of aldosterone and its associated steroid hormone profile including aldosterone (ALD), 18-hydroxycorticosterone (18-OHB), 18-hydroxycortisol (18-OHF), 18-oxocortisol (18-OXOF) and cortisol (F) is critical for the screening, confirmatory testing, and subtype classification of primary aldosteronism (PA). Conventional hormone extraction methods, such as solid-phase extraction and liquid-liquid extraction, are labor-intensive and time-consuming, thereby limiting their applicability and widespread adoption in clinical laboratories. This study developed a novel high-efficiency methodology integrating automated magnetic solid-phase extraction (MSPE) pretreatment with liquid chromatography-tandem mass spectrometry (LC-MS/MS), enabling simultaneous and accurate quantification of ALD, 18-OHB, 18-OHF, 18-OXOF, and F. To ensure the reliability and practicality of the new method, a comprehensive validation of its linearity, accuracy, precision, matrix effect, carryover, stability, and specificity was conducted, and a comparison was made with the traditional solid-phase extraction method. Under optimized conditions, the method demonstrated a satisfactory linear range (18-OHB/18-OHF/18-OXOF: 5-3000 pg/mL, ALD: 0.02-10 ng/mL, F: 2-1000 ng/mL) and extremely low limits of quantification (18-OHB/18-OHF/18-OXOF: 3.75 pg/mL, ALD: 0.02 ng/mL, F: 1.5 ng/mL). Moreover, the recoveries of the five analytes ranged from 90.23% to 104.27%, and the repeatability was between 0.23% and 5.45%. Notably, the magnetic bead-assisted extraction method did not show obvious matrix effects or carryover problems. The target analytes in the processed sample remained stable for 24 h at room temperature and under autosampler conditions. There was a good correlation between this method and traditional solid-phase extraction method. MSPE serves as a critical technological link between complex manual procedures and high-throughput clinical MS. By leveraging its inherent compatibility with automation to streamline workflows and enhance efficiency, it facilitates the broader adoption and application of clinical MS technologies. In conclusion, we have developed a novel method combining magnetic bead extraction with LC-MS/MS that enables simultaneous quantification of ALD, 18-OHB, 18-OHF, 18-OXOF and F for the screening and diagnosis of primary aldosteronism (PA), with potential for further application in clinical research.