Amphetamine radioimmunoassay: chemical tuning of specificity.

Four [125I]iodine labelled amphetamine derivatives were synthesised. Three of these proved useful in the development of radioimmunoassays for amphetamine. The assays, all using the same antiserum, had widely differing specificities for compounds closely related to amphetamine. Thus, chemical modification of the radiotracer was used to tune radioimmunoassay specificity without recourse to the production of different antisera.