Freeze and Squeeze
dkim at nmsu.edu
Thu Jun 13 15:51:33 EST 1996
I have been using (expensive) microfuge filter cups (e.g. S&S Ultra-Free
MC). These cups cost about US$1 each, but we had a bag of them, and
noone was using them in the lab. I would take a bit of the gel slice
(this is a SMALL piece of gel) and freeze in the -80 (I am impatient).
I'd then put the frozen gel into the cup and let thaw, then spin out the
liquid in the microfuge (a 5 second pulse). I use the eluted liquid
directly for ligations.
I have since run out of the cups, and cannot justify purchasing more. I
have instead tried placing the gel slice (frozen) into the top of an
"aerosol barrier" pipet tip, and place the tip into a 1.5 ml tube. Put
the tube into a microfuge and spin for a 3 - 5 second pulse. The barrier
effectively prevents bits of agarose from passing through, and the liquid
seems to be fine for ligation. These barrier tips are much cheaper than
I may try using barrier tips for other filtration needs. Maybe I can
make a micro spin-column out of one . . .
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