Dear Alan,
I have also seen a residue problem on sequencing plates. It must be a
residue left over from the gel because on Mondays, after the gel has sat
over the weekend, it is more difficult to rinse away. I don't know what
the exact cause is but have a fix that works for us. For the 377 plates,
our solutoin has been to stop washing with alconox except if build up is
really bad (maybe once every other month). We rinse and scrub using a
paper towel first with nanopure water, then with a 10% HCl solution and
then with nanopure water again. We dry the plates with paper towels and
then on the bench before making gel sandwich we wipe the plates 3X'x with
nanopure water and 3x'x with 100% EtOH. This is our daily procedure. I
noticed that the residue began to build up along the sides of the plates
first. Now we extend the rinsing with nanopure water and 10% HCl to our
spacers and there seems to be less residue building up. We pour by
capillary action not with the injectors that were supplied so the plates
must be as clean as possible to avoid bubbles. If the gel pouring begins
to slow too much even after washing with nanopure water and 10% HCL
(resulting in a field of small bubbles), I'll rinse the plates with
nanopure water, then 1N NaOH then, 10% HCL then fianlly with a lot of
nanopure water. We use alconox only if it is really bad or a new set of
plates. It seems like a long process for washing plates but it only
takes
a few minutes extra and concidering how much work goes through the gel it
is worth the extra few minuter at the sink. For the 373 plates the
problem
is very minor since we still use the .4mm spacers. If we are using the
373
daily we will rinse once a week with 10% HCl. If it has been a few days
sinse using the 373 we will go ahead and rinse with 10% HCl.
Good luck,
Shirley Hall
Dept of Molecular Biology and Oncology
Univ of Texas Southwestern Medical Center
e-mail: shall at hamon.swmed.edu
