Surface plasmon resonance

most widely used methods for determining binding constants.

The method is based on the principal that the angle of

maximum extinction of the plasmon on gold is strongly

dependent on the index of refraction of the medium.

This technique is illustrated in the following. In the first

scheme a particle angle gives a minimum for a particular

sample cell. When a binding even takes place on the gold

surface, this results in a shift in the minimum angle. The

detection of this shift results in a determination of the

amount of binding. The concept is illustrated schematically

in the next two frames.