Endogenous cardiac steroids are specific inhibitors of the sodium pump (Na+/K+-ATPase) and play important biological roles such as regulating cell growth, differentiation, apoptosis, fibrosis, immunity, carbohydrate metabolism, and nervous and mental functions. Detecting endogenous cardiac steroids from biological fluids is challenging because of their low concentration ranges (pg–ng/mL) and lack of authentic standards.

Access this application note to learn how a novel structure-based MSⁿ discovery approach, utilizing the Thermo Scientific™ Orbitrap ID-X™ Tribrid™ mass spectrometer, enables annotation of cardiac steroids and related compounds based on basic steroid sub-structure identification using MS² and MS³ spectral tree data.