On Tue, 12 Sep 2000 10:43:11 -0700 Sandy Kielland <Kielland@uvic.ca> wrote:
> Hello all;
> Have any of you protein sequencing people been having trouble with short
> lifetimes on ABI PTH columns? Over the years I have expected these columns
> to last 3-4 months with careful use, but lately this has not been the case.
> I treat them very gently, break them in properly and run the older slower
> gradient to keep operating pressures low. I use ABI solvents and reagents.
> Under the assumption that there is something wrong with my instrument
> (ABI473) maybe leaking something nasty and poisoning the column, I have
> replaced the conversion flask and the only valve block I could find with a
> leak, block 1. Hasn't made a bit of difference. The symptoms are that my
> hydrophobic residues are disappearing. Weird, I know. I will see data
> something like this....
>
> 1. asp 8 picomoles
> 2. thr 5 "
> 3. pro 9 "
> 4. val 0 "
> 5. ser 3 "
> 6. asn 8 "
> 7. leu 0.2 "
> 8. tyr 1 "
>
> When I say "0" for valine, I really mean "0"...not even a whisper. It's
> obviously being coupled and cleaved OK, but where did it go? Today I've
> installed yet another new column and will get beautiful data for about 3
> weeks, then it will start to deteriorate again. Any hints much appreciated.
>
> Best regards,
>
> Sandy Kielland
> Victoria Protein Microchemistry Centre
> Department of Biochemistry and Microbiology
> University of Victoria
> Victoria B.C. CANADA
> phone: (250) 7218884
> FAX (250) 7218855
> Email Kielland@UVic.ca
> Webpage http://www.proteincentre.com
>
Sandy,
I have encountered a very similar problem.All the PTHs were OK until after Pro
and then the peak heights dropped dramatically.Columns were changed,blocks
cleaned,hair pulled out etc etc.If you are using ABIs B2 then this may not
apply but I went back to adding DMPTU to B and I now have decent sized peaks
again.
Sandy.
----------------------
Alex Carne,
Head of Protein Characterization,
Institute of Cancer Research,
Chester Beatty Labs.,
237 Fulham Road,
London SW3 6JB, UK.
Tel: +44(0)171 878 3815 (Office)
Tel: +44(0)171 970 6003 (Lab)
Fax: +44 (0)171 352 3299
E-mail: sandyc@icr.ac.uk
Mobile: 0370 365 032
This archive was generated by hypermail 2b29 : Wed Sep 20 2000 - 11:12:13 EDT