Separation of distinct lipid membrane domains in cell membranes has been suggested to play important roles in many cellular processes by providing microenvironments to cluster or to isolate membrane biomolecules. One important class of membrane domain is called a lipid raft and some signaling proteins and glycolipids have high affinity for these domains. However, many experimental determinations of biomolecule residency in rafts occur at equilibrium or fixed conditions, precluding measurement of dynamic information. We report a new method for measuring the partitioning kinetics of membrane biomolecules to different lipid phases using a patterned supported lipid bilayer platform composed of liquid-ordered (lipid raft) and liquid-disordered (unsaturated lipid-rich) coexistent phases. Laminar flow inside a microfluidic channel patterns bilayers with coexistent phases in predetermined locations, eliminating the need for additional components to label the phases. Using a hydrodynamic force provided by the bulk flow in the microchannel, membrane-bound species can be transported in the bilayers. The pre-defined location of stably coexistent phases, in addition to the controllable movement of the target species, allow us to establish when and where the target molecules approach or leave different lipid phases. Using this approach with appropriate experimental designs, we obtain the association and dissociation kinetic parameters for three membrane-bound species, including the glycolipid, GM1, an important cell signaling molecule. We examine two different analogs of GM1 and conclude that structural differences between them impact the kinetics of association of these molecules to raft-like phases. One possible extension is measuring the partitioning kinetics of other glycolipids or lipid-linked proteins with posttranslational modifications to provide insight into how structural factors, membrane compositions, and environmental factors influence dynamic partitioning. We also discuss the possibilities and limitations for this method.