Hi,
I've been having some recurring problems with our HP1100 and we (the Agilent
tech people and myself) can't seem to figure out what's going on. I thought
maybe somebody here could help.
We normally run RP-HPLC and have encountered no difficulty with the instrument.
Recently we did some size-exclusion chrom. with 150mM salt and the fun began. It
ran without incident for about 2 weeks (running nearly 24h/day). Slowly the back
pressure built up until it reached the upper limit for the column. I follwed the
column directions and washed it with 0.5N NaOH follwed by buffer follwed by 20%
MeCN. Lots of stuff came off the column but the back pressure was still too
high. I narrowed it down to the HPLC itself and washed it (without the column in
line) with; hot water, dilute TFA, dilute HCl, dilute HNO3, and various
concentrations of MeCN (not in that order). The nitric acid killed everything.
The system was completely blocked, so I called in a service person. After two
visits he changed the pump seals and all of the frits and it ran for a couple of
days before the back pressure problems crept up again.
We can't quite figure out what is happening. Something is clogging up the
system, but I'm taking all precautions that I can think of to stop it from
happening. I'm sterile filtering all buffers on a weekly basis. I've changed the
purge valve frit every couple of days and I've cleaned the frits in the solvent
bottles at least twice since the trouble began and I've changed the filter on
the column (which looked like it was dragged across the floor).
If anybody has a clue what happened to our instrument and how I can fix it I'd
love to hear about it. The instrument is under service contract so I don't have
to worry about the cost of repair, but I don't want to waste Agilent's time and
money fixing the symptoms rather than the problem itself. Changing frits is
definately not curing the problem.
Thank you in advance for any assistance you can offer.
Jeni
Janelle Lauer-Fields
Department of Chemistry & Biochemistry
Florida Atlantic University
777 Glades Road
Boca Raton, Florida 33431
561-297-2094/Fax 561-297-2759
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