precipitation of oligos

Jouko Kalevi Pettersson petterss at klaava.Helsinki.FI
Thu Apr 1 11:14:15 EST 1993


DAVID F. BISHOP (BISHOP at MSVAX.MSSM.EDU) wrote:

> However, I would dearly love to save our vacuum pumps from all this ammonia
> vapor.  Does anyone have experience with using smaller volumes of butanol
> or with centrifugation at lower speeds (but not for 2 hr)?

I scaled the method up. I use 15 ml screw cap tubes and spin them
for 10 min at 2000 G. For the cleavage of oligos from the CPG cartridge
I use 1.5 ml of 25% ammonia. This amount goes into 10 ml of the
n-butanol phase completely. The yield is usually more than 90%.  
I dissolve the precipitate into 1 ml of ultrapure water and repeat the
n-butanol precipitation and dry in Hetovac. No troubles with ammonia 
vapour anymore!


-- 
Jouko Pettersson                 Email: Jouko.Pettersson at Helsinki.Fi
Department of Biochemistry
University of Helsinki



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