It's good to hear someone else in ABRF actually uses an Alpha Plus. I was
beginning to think we were the only group!
Regarding your problem with pressure, if you have narrowed it down to the
column then you are running out of options. It's got to be either the fri=
ts
and/or the resin, or maybe the tubing as it enters the connections. I
assume that you are using the PEEK column system? (If not, then recommend
it over steel). First check that the tubing in the peek couplings has not
been pinched as this can lead to a pressure build up. If it has, remake t=
he
joint or even replace the line from the autosampler to the column. Replac=
e
frits regularly.
When cleaning the resin it is important that a fining step is carried out.
This is a rather stressful exercise as the resin is so expensive, but it'=
s
the only way to maintain the resin quality. The manual does not emphasize
this. After cleaning the resin and boiling in alkali, add water, mix and
let the resin settle for a few minutes. Decant off the 'haze' above the
resin bed. Add more water (100ml) and repeat the process twice more. If
there are substantial fines then the 'haze' will get less each time. It i=
s
important that you add enough spare resin (say 0.5g)to the column resin
before the cleaning procedure to cover the losses on fining and packing.
Once repacked, check for headspace after overnight run. We have
occasionally solved a pressure problem by inverting the column - can save
having to clean and repack. Check that your autosampler is working proper=
ly
as if the rotor seal is worn, it may occlude free flow and leads to
pressure build up.
Finally talk to your agent about Biochrom repacking your column. We tried
the service a couple of weeks ago and they charged us about =A31000 (vs =A3=
4000
for a new column). In reality, they replaced the column as the original
resin batch was no longer available (>8yrs old), so we are happy. I suspe=
ct
this may be their regular choice anyway as I cannot see them committing a=
n
individual to cleaning a single column. Much more cost effective for them
to simply swap columns and then batch clean a whole pot full of resin of =
a
given lot number. I've no evidence for this, by the way - just conjectur=
e!
Good luck
Len
>Can someone help us please. We are having trouble with our AAA (Pharmac=
ia
>Alpha Plus).
>
>We seem to be having a lot of pressure problems. We have thoroughly
>cleaned the resin using the recommended protocol, and repacked the colum=
n
>several times. After this procedure the pressure returns to normal.
>When the column is properly packed down, we get an increase in pressure =
to
>90 kg /cm2. It then only takes a few samples for the pressure to get to
>danger levels. Yes everything is filtered through a .22 micron filter
>including the buffers. We have looked at the resin under a microscope a=
nd
>there appears to be little damage to the spheres. However there does
>apear to be a very small quantity of fibrous material in the resin. (We
>must stress only a small amount). Could this be enough to cause this
>pressure problem? We have thoroughly cleaned out the lines, and have
>established that the problem is resin related by isolating each part of =
the
>system in sequence.
>
>How do we get rid of this material if it is indeed the cause ? Would be
>glad of any suggestions as we are desparate. (We can't afford to replace
>the resin)
>
>Thanks
>
>Gill Norris and Dave Harding
*********************************************************************
Dr Len C. Packman
Assistant Director of Research
Protein and Nucleic Acid Chemistry Facility
Department of Biochemistry
University of Cambridge
80 Tennis Court Road
Old Addenbrookes Site
Cambridge, CB2 1GA, UK
Tel: +44 (1223) 333639
FAX: +44 (1223) 766002
e-mail: lcp2@mole.bio.cam.ac.uk
Visit my WWW page at http://www.bio.cam.ac.uk/proj/adr/PNAC/pnac.html