abi autosequencing problems

Manfred Schloesser Mschloe1 at gwdg.de
Thu Apr 11 03:39:06 EST 1996

In article <4kfm4f$q4r at net.bio.net>, Karen Lynn Hershberger
<khershbe at ezinfo.ucs.indiana.edu> wrote:

> Hi All!
> After 3 months of no problems, I have two sets of ABI 36 inch  plates that 
> are massively fluorescing red or green.  I have tried cleaning repeatedly 
> with Alconox, soaking in 3M HCl, and soaking in 10% 
> KOH and EtOH, all of which takes some of it off but not everything.  The 
> ABI guys ahve been out twice to check the machine, and says its fine.  
> They suggested that it was the MeOH that I use to clean the plates that 
> caused the fluorescence, but I have been using all along without a problem.  
> Any ideas on how to clean the plates and what may have caused the problem 
> in the first place (I don't want to go through this again!).
> Thanks for any help! 
> Karen Hershberger
> Indiana University, Pace Lab

Hi Karen,
what kind of ABI sequencer are you using? An old 373 or the new 377 which
is much more sensitive? I have two 373 and one 377. I noticed that with
some brand of MeOH or EtOH you get these background fluorescence. If they
are definitely not the cause the background fluorescence could  be due to
the fact that you did not align the plates perfectly parallel, a slight
tilt and you get this reflection into the detector.
Furthermore, you should check this metal bar on the front of the plate
which is constructed in such way that no background scattering reaches the
detector. It sits right in front of the wheel.  Sometimes you will find
some dried up buffer inside which causes this background fluorescence.
Just wipe it out with some EtOH.

In my lab I am using a regular  dishwasher hooked up to the deionized
water supply, super clean plates and no problems anymore. You can use them
as they come out of the washer..

I hope that  I could help you with your problems.

Manfred Schloesser  (Mschloe at gwdg.de)

Institute of Human Genetics, University Goettingen, Germany

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