David,

I have found that the best solvent to remove Santovac is chloroform.  While
this has attendant safety problems it's removal of Santovac is nothing short of
remarkable.

I would suggest that as a precaution you clean the whole mass spectrometer.  It
is far easier to do a good job once then to have to strip the instrument down
again if the peak shapes are poor or the stability bad.

Was the source on when this occurred?  If so then Santovac maybe baked onto the
source in which case it would be advisable to strip the source.

The collector should be cleaned as a unit.  NEVER take a Prism collector to
pieces unless you have a lot of patience to re-assemble it.  Simply remove the
collector housing, with collectors, from the flight tube.  Put bolts into the
screw holes for the head amp and rest the housing open end up.  Fill with
solvent for 10-15 minutes and dry.

Check inside the foreline traps and the Pirani heads for collected Santovac.
If the foreline traps are contaminated you will have to replace the mol sieve
but the Pirani heads can be cleaned in solvent.

After the chloroform dry in an oven at 75'c or for the larger pieces with a hot
air gun.

Cheers

Peter Stow

David A. Hodell wrote:

> I am seeking advice on cleaning solvents and procedures to remove diffusion
> pump oil (Santovac 5) from the pipework of a mass spectrometer
> (VG/Micromass PRISM SeriesI).    The chilled water line that cools the
> Diffstaks broke and the thermal trip failed to turn the diffusion pump
> heaters off, so the Diffstaks remained hot for 8 hours with no circulation
> of cooling water.  After removing both the source and collector Diffstaks
> (150L/s), there was evidence of condensation of Santovac on the baffles in
> the pipework leading to the collectors.  The baffles in the pipework under
> the source did not have visible evidence of diff pump fluid and the source
> and source housing visually appeared to be clean.  The pipework containing
> the inlet and changeover diffusion pumps (40 L/s) was contaminated with
> diff pump oil.  Has anyone had experience with such a calamity and what is
> the best way of going about cleaning the contaminated pipework.  Edwards
> recommends cleaning with GENKLENE (stabilized trichloroethane) followed by
> rinsing with acetone and baking at 75 oC.  Any advice as to how to proceed
> would be most appreciated.  Also, has anyone replaced their diffusion pumps
> with turbos on an older model PRISM?
>
> Grieving in Gainesville,
> David Hodell
>
> David Hodell
> Professor of Geology
> University of Florida
> P.O. Box 117340
> Gainesville, FL  32611-7340
> http://ess.geology.ufl.edu/hodell/hodell.html
>
> Please Note: My new e-mail address is [log in to unmask]
> All mail to the old address will be forwarded to the new one.



--
                                 ISO-MASS Scientific Inc.
                                319-5940 Macleod Trail S.W.
                          Tel. (403)255-6631 Fax. (403)255-6958
                    Toll Free 1-800-363-7823  EMail [log in to unmask]