When the synthesis is completed the oligo is cleaved from its solid support and deprotected in basic solutions such as ammonium hydroxide. The solution contains the full-length oligo and truncated failure sequences. These failure sequences can be removed by reverse-phase cartridge, reverse-phase HPLC or Polyacrylamide Gel Electrophoresis (PAGE).
Read more about your purification options at respectively method.
Oligos are in general very stable and are best stored lyophilized in -20°C and second best in water -20°C.
Read more about storage conditions at Storage
