Quantification of Cytokinins using High-Resolution Accurate-Mass Orbitrap Mass Spectrometry and Parallel Reaction Monitoring (PRM)

Cytokinins (CKs) are adenine derivatives that act as phytohormones. These signaling molecules control plant cell division and differentiation, organ growth and senescence, and orchestrate plant interactions with biotic and abiotic environments. While CKs are predominately recognized as plant-based substances, CKs have been found across different domains of life, including microorganisms, insects, mammals, and humans. In plants, CKs act at trace, often low femtomolar concentrations; therefore, sensitive and precise analytical techniques are required to accurately detect and quantify them from complex biological matrices. Here, we report the first comprehensive CK quantification method using a QExactive Orbitrap mass spectrometer in high-resolution with a parallel reaction monitoring (PRM) based approach. The current method progresses upon multiple reaction monitoring (MRM) methods, previously used for CK profiling on triple quadrupole mass spectrometers. This method offers improved mass accuracy and the co...