How quickly can a small-molecule binding affinity (KD) be measured? In this Fidabio webinar, RapidKD shows that a small-molecule KD can be determined in about a minute with Flow Induced Dispersion Analysis (FIDA). Instead of a full multi-point titration, a Taylor-dispersion concentration gradient inside the capillary performs a single continuous titration, read out by FIDA Lambda Dynamics from just two samples and nanogram amounts of protein, after a three-minute quality-control check for aggregation, stickiness and labelling. On a Fida Neo, RapidKD ranked carbonic-anhydrase inhibitors across nanomolar-to-micromolar affinities, in agreement with full binding curves and SPR, and also worked label-free using intrinsic tryptophan fluorescence. It is an example of using FIDA to accelerate small-molecule affinity screening in solution.