S 1888 (OTTO) Sodium dihydrogen orthophosphate, dihydrate, for HPLC, 99%+ Cas 13472-35-0 - used in the preparation of biological buffers. S 1888 (OTTO) Sodium dihydrogen orthophosphate, dihydrate, for HPLC, 99%+ Cas 13472-35-0 - used in many applications including in gel electrophoresis.