Source for glassmilk [recipe]

K. Wernars lwlkarel at rivm.nl
Thu Nov 16 04:57:15 EST 1995


In article <1995Nov14.234715 at emuvax.emich.edu> bio_hannan at emuvax.emich.edu writes:

>In article <48b2nb$2n6 at pearl.whoi.edu>, hemant at hoh.mbl.edu (Hemant Chickarmane) writes:
>> Does anybody know of a source for glassmilk, the silica slurry that is
>> used for DNA purification in the presence of chaotropic salts.  A source
>> other than a kit itself.  I oresume the material is silica,
>> unless it happens to be finely ground glass.  If it is silica, would TLC
>> grade silica gel say 50 micron size be suitable.
>> 
>> Thanks for any information.
>> 
>> 
>> Dr Hemant Chikarmane, Marine Biological Laboratory, Woods Hole, MA 02543 USA
>>            email: hemant at mbl.edu	voice: (508) 289-7245
>> 
>>       ****    Experience Fahrvergnuegen - Drive a Macintosh    ****
>> -- 
>> Dr Hemant Chikarmane, Marine Biological Laboratory, Woods Hole, MA 02543 USA
>>            email: hemant at mbl.edu	voice: (508) 289-7245
>> 
>>       ****    Experience Fahrvergnuegen - Drive a Macintosh    ****

>Someone here a while back said that Sigma sells a silica product that is
>just powdered glass that you can suspend in buffer to make glassmilk.
>There is also a recipe for the whole process on the net somewhere for the
>do-it-yourselfers.  I don't have the details on the product, though.  Anyone else 
>have it?

Dear do-it-yourselfers,

Some months ago I have posted a recipe for preparing glassmilk. I used
it successfully long before glassmilk was commercially available. The
procedure is simple, cheap and yields an excellent opportunity to exercise
the arm muscles. Here it is:

1) As a starting material use glassfiber-filters (approx. 100 piece Whatman GF/A
or GF/C) or some borosilicate glass (e.g. from scintillation-vials).
2) Grind this material to a fine powder, using a pestle and mortar (this is the
exercise-part).
3) Put the powder in 250 ml dist. water, stirr for 1 hr, let it stand undisturbed
for 30 min.
4) Take the supernatant, spin it in a tabletop centifuge for 1 min.
5) Decant the supernatant and resuspend the pellet in dist. water (approx. the same
volume as the pellet)
6) To this suspension add an equal volume concentrated nitric acid and put the
mixture for 15 min. in a boiling waterbath. [NB.: USE A FUMEHOOD AND PROTECTIVE
CLOTHING]
7) Repetedly resuspend and pellet the glasspowder in dist. water until pH is neutral.
8) The final suspension (1 vol. glasspowder + 1 vol dist. water) can be stored
at 4·C. Homogenize the suspension carefully before use.


Dr. K. Wernars.



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