wetsel_r at wetsel_r at
Thu Nov 19 11:44:02 EST 1992

In a previous article, obrien at (Darin O'Brien) wrote:
>I have an oligo given to me by someone else.  Unfortunately, the oligo was not
>deblocked and nobody around here knows how to do it.  Does anyone out there know
>how to do this?  I don't know what solution the oligo is in now.  Can I
>just precipitate the oligo and treat overnight in ammonium hydroxide?  Any help
>would be greatly appreciated.


I assume that the oligo has been deprotected and off the column?  If so, I 
would assume that they are currently in NH4-OH.  Deprotection is then easy. 
We have our oligos in 4ml Wheaton vials available from VWR/Fisher which fit 
nicely into a heating block.  Heat them overnight at 60'C.   It can be done 
in an eppendorf tube as well, in fact there is probably no reason why 
deprotection couldn't be done in a 60'C water bath as long as absolute care 
is taken not to get any water mixed into the oligo.  In the morning, we 
would take 1 ml and then lypholyze it down to dryness, resuspend in 250ul 
water and take OD-260 readings.  Very recently, this net has directed my 
attention to an n-butanol purification/extraction (NAR 19:674) which works 
like a charm!

Good luck and holler if I can help further...

David L. Haviland
haviland at

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