Simultaneous stable isotope dilution targeted and untargeted steroid analysis with Girard P derivatization on a QExactive high resolution mass spectrometer.

摘要

Analytical challenges in detecting steroid metabolites include their low ionization efficiency under most source conditions, and developing sufficient sensitivity and specificity for analysis of low abundance analytes in complex matrices. Stable isotope analogs provide exceptionally sensitive and specific quantitative measurements by adjusting for losses during storage, extraction and analysis. To further augment sensitivity, we examined Girard P derivatization for the analysis of free testosterone (T), and rostenedione (AD), and dehydroepiandrosterone (DHEA). We performed all analyses on a QExactive Plus hybrid triple quadrupole/Orbitrap mass spectrometer in positive ion mode operating in alternating full scan and MS/MS modes. This enables both targeted and untargeted quantitation of a sample with reduced instrument run time, less sample usage, and increased rigor of analysis.