Oligonucleotide purification  1. Add 400 ul of TE buffer then 400 ul of 1-butanol to the oligonucleotide glass vial. 2. Vortex well, then spin down in tabletop centrifuge for 10 minutes at ~2,000. rpm¹s. 3. Remove top, butanol layer with a sterile pipette tip and discard. 4. Add another 400 ul of 1-butanol. 5. Vortex well, then spin down as above in tabletop centrifuge. 6. Remove top, butanol layer and discard.  7. Transfer aqueous phase into a new 1.5 ml tube. 8. Dry in a speed vac for about 5 minutes to remove all of the butanol. 9. Add 50 ul of 5M KAc and fill tube with 95% ETOH. 10. Precipitate for at least one hour at -70¹C. 11. Spin for 15 minutes/ 4¹C/ maximum speed.  12. Pour off ETOH and dry in a speed vac as above. 13. Add 500 ul of TE buffer to your oligo. in the 1.5 ml tube and mix well. 14. Dilute 1:10 and/or 1:100 and read on spectrophotometer to determine concentration. 15. Follow product specification sheet to determine volume needed to make a 20 um 	solution.