The Biacore^® T200 is especially well suited to studies of binding of small molecules to macromolecules, because of its greater stability and sensitivity. Typically, the latter are captured directly or indirectly on the chip surface and the small molecule is flowed over the surface as the analyte. The change in surface plasmon resonance is monitored, as it is for other binding interactions, and the kinetic constants and binding constants are calculated. The image below illustrates one such experiment with an analyte with a molecular mass of 259 Da. The binding affinity calculated from the curves is 1.14 x 10^-6 M.