QIAGEN at kaiwan.com
Mon Mar 27 14:52:43 EST 1995
In article <3ksu9d$5oq at lll-winken.llnl.gov>, maria at acme.llnl.gov () wrote:
> We are using Qiagen's 96-well manifold to isolate M13's. They have been working out so far but recently, a collegue in our lab is only able to isolate 12 random samples out of 96. When she repeats the experiment on the regular 8-strip manifold, she is able to isolate all 96 in very good quantities.
> This has been going on for the past week and a half and every time she repeats the experiement on the 8-strip, it works out fine.
> Is anyone else experiencing this problem? How have your experiences been?
> Maria De Jesus
> Lawrence Livermore Laboratory
> maria at acme.llnl.gov
Your problems with variable yield from QIAGEN's QIAprep M13 products are
likely to result from incomplete removal of ethanol following the PE wash
step. Since your preps are working well with QIAprep 8 M13, you can rule
out any culture-related problems and, if you are using the same buffers,
any buffer- related problems. The procedure for removing ethanol from our
96-well plates is similar to that for strips, but since there are many more
wells complete removal may require extra diligence.
The process for ethanol removal is as follows: First, remove the QIAprep 96
plate from the manifold and rap it firmly on a short stack of paper towels.
Be sure to contact the stack squarely with the bottom of the plate to avoid
breaking the nozzles. Droplets of ethanol from the membrane, and from the
collars and nozzles at the base of each well, will come off onto the paper
towels. Remove any additional traces of ethanol from around the nozzles and
collars with a tissue or Kimwipe¨. Put the plate back on the manifold, and
run the vacuum at a high setting (not to exceed 4-500 mm Hg) for 1 min.
Remove the plate once more, and repeat the ethanol removal steps on fresh
paper towels. This will remove any droplets that may have fallen from the
walls of the well onto the membrane in the first ethanol removal step. When
no more drops come off, and when no droplets are visible in the wells or
around the nozzles of the QIAprep 96 plate, put the plate back on the
manifold and run the vacuum for an additional 5 min. This should remove all
remaining traces of ethanol.
Another tip that you may find useful is that the efficiency of elution from
the QIAprep membrane can often be enhanced by heating the elution buffer to
50¡C before use.
Temporary Email Address qiagen at kaiwan.com
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