Radioimmunological determination of fenoterol. Part I: Theoretical fundamentals

A general solution is given for the system of equations describing coupled mass equilibria having m antibodies with one binding site, or with several mutually independent binding sites of equal intrinsic affinity (immunoglobulin (Ig) G antibodies) and n monovalent antigens. Based on this a formula is given with which it is possible to calculate the minimum association constant of the antibody and the minimum specific radioactivity of the tracer in a radioimmunoassay when the detection limit is given and the assay conditions are established. The model m = 2 and n = 4 describes the behaviour of a system which is based on a mixture of stereoselective antibodies and a racemic tracer. The effect of the enantiomer ratio of an optically active ligand on this system is demonstrated.