ABSTRACT
Microplate surface scintillation effect or scintillation proximity (1) counting requires a solid support coated with scintillant for detection of beta particles as radioisotopes decay. Due to the inability of beta particles from tritium and other weak emitters to travel more than a few microns in aqueous solutions (2), beads or microplates coated with scintillant and then binder molecules such as receptors or antibodies provide an excellent support of the reaction of binding with radioactive ligand and subsequent detection of only bound radioactivity. Since the scintillant is in the microplate or bead, no addition of scintillant is needed prior to detection. This allows for one-step assays to be designed in many cases, greatly reducing the volume of radioactive waste as well as reducing the time and labor required for the assay. 125I can be detected due to the production of Auger electrons in water as the gamma emitter decays (2).
