I had my student try to purify a 200bp fragment from a gel using the NA45
paper technique, recently discussed here on this news group. After she did
the hi-salt washes and the EtOH precipitation (+glycogen), there was no
normal pellet but a nonaqueous "bubble" in the bottom of the microfuge tube.
After adding TE and doing a second EtOH precipitation the same result
occured. Could this result from carry over from the hi-salt washes? Any
thoughts on this problem would be appreciated. Thanks.