P 2339 (OTTO) Potassium iodide, bio-ultra, 99.5% Cas 7681-11-0 - used in pharmaceutical formulations and in film photography as a source of iodine. P 2339 (OTTO) Potassium iodide, bio-ultra, 99.5% Cas 7681-11-0 - used as an analytical Reagent in iodometric tritrations.