sequencing signal dies after 100 bases?!

Jan Hoolwerf hoolwerf at
Tue Feb 4 04:35:38 EST 1997


Recently we ran into a nasty problem with sequencing on an ALF-red sequencer.

The run starts with normal peaks (nice sharp peaks, good resolution) but
between 100 bases and 125 bases the signal detoriates: low, braod peaks, bad
resolution. No detection possible anymore.

We ran the same products at the same time (the rest like gel etc. also
identical) on an ALF-express and..... no problems, good results. As usual.

The glass plates are clean (as far one can see that) and have no visible
scrathes or whatever and are always cleaned in the same way: a non-fluorescent
detergents and water and ethanol.

The advise of the manufacturer was (without any explanation): try new glass
plates. And, to our surprise, things are completely normal again.

That brings me to these questions:

1) has anyone experienced something like this?

2) what can be the difference between new glass plates and used ones but
thoroughly cleaned every time.

3) is it possible to "revive" the old glass plates? How?

Any input is welcomed!

with regards, Jan Hoolwerf

******************* these words were mine, all mine !! ********************
 J.D. Hoolwerf
 Neth. Inst. for Dairy Research
 P.O. Box 20                        phone  : 31-318-659511
 6710 BA  Ede                       fax    : 31-318-650400
 the Netherlands                    e-mail : hoolwerf at

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