Methods employing alumina as an adsorbent were developed for tbe separation and purification fluorine-18, molybdenum-99, techetium-99m, tellurium- 132, and iodine-132. Alumina in acidic form behaves as an anion exchanger and adsorbs anions from solution, allowing cations to pass through. In the basic form it behaves as a cation exchanger and will adsorb cations and have no effect on anions. By varying tbe pH, different ions may be selectively eluted, depending upon how firmly they are bound to the alumina. Relatively small volumes of reagents are required, and rapid separation may be effected. (C. H.)