Native mass spectrometry (nMS) - electrospray ionization (ESI)-MS carried out under physiological solution conditions with experimental/instrumental parameters that preserve the non-covalent interactions present in solution - has become an indispensable tool in glycomics research. When performed with the catch-and-release (CaR)-ESI-MS technique, nMS serves a sensitive, label-free method for screening glycan libraries (defined and natural) against glycan-binding proteins (GBPs) and accelerates the discovery of ligands and provides new insights into the fine glycan specificity of endogenous and exogenous GBPs. When combined with model membranes, such as nanodiscs, nMS allows for the detection of glycosphingolipid ligands and the quantification of their interactions with GBPs. Implementation of nMS in a time-resolved manner enables the precise measurement of the kinetics and substrate specificities of carbohydrate-active enzymes (CAZymes). This talk will review recent advances in nMS methods for natural glycan library screening (concentration-independent (COIN) nMS) and quantification of glycan/glycoconjugate interactions with GBPs (slow-mixing mode (SLOMO) nMS). New methods capable of quantifying the relative substrate specificities of CAZymes will also be presented, together with examples of how this information can be exploited for precision glycoengineering and cancer diagnostic applications.-Dr. John S. Klassen