One of the oldest methods used for the quantitation of drug molecules is radiometric analysis. This generally involves quantitation of radiation from beta-emitting radioactive isotopes such as 14C, 3H or 32P. Radiometric analysis is one of the most precise, sensitive, and efficient detection methods; however, there are many technical and social challenges with using this technology. Radiometric analysis begins with a radioactive isotope being incorporated into the drug molecule via a chemical sy