Discussion:
Loss of polar compounds in an ion trap
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Murray R Darrach
2007-07-11 17:14:08 UTC
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Hi all,

Anyone have any insight into this phenomenon?

Titanium custom machined quadrupole ion trap that slowly over time lost the
ability to "see" polar compounds (e.g. ethyl acetate, alcohols).

Cleaning the MS with sandblasting, jewellers rouge, and solvents has not
solved the problem.

Sounds like a bit of sci-fi, but measurements don't lie.
d***@hotmail.com
2007-07-11 20:26:25 UTC
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Post by Murray R Darrach
Hi all,
Anyone have any insight into this phenomenon?
Titanium custom machined quadrupole ion trap that slowly over time lost the
ability to "see" polar compounds (e.g. ethyl acetate, alcohols).
Cleaning the MS with sandblasting, jewellers rouge, and solvents has not
solved the problem.
Sounds like a bit of sci-fi, but measurements don't lie.
I'm working with a quadrupole ion trap MS. Cleaning is only part of
the solution. When we measured the (nominal) 15 kV dynode power
supply, we found it only gave 600 Volts. Did you draw any conclusions
from cleaning? In our case the stains were indicative of vacuum arcing.
John Dulak
2007-07-11 22:56:16 UTC
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Post by Murray R Darrach
Hi all,
Anyone have any insight into this phenomenon?
Titanium custom machined quadrupole ion trap that slowly over time lost the
ability to "see" polar compounds (e.g. ethyl acetate, alcohols).
Cleaning the MS with sandblasting, jewellers rouge, and solvents has not
solved the problem.
Sounds like a bit of sci-fi, but measurements don't lie.
Murray:

Could the Titamium be acting as a "getter" and be particularly
effective with polar compounds?

http://www.thevalvepage.com/valvetek/getter/getter.htm

John
--
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'' Madness takes its toll - Please have exact change. ''

John Dulak - Gnomeway Services - http://tinyurl.com/2qs6o6
Sassman
2007-07-12 14:44:10 UTC
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The ion trap can only trap ions. Hence the polar compounds must first be
ionized in some way for them to be seen by the MS. What ionization
method are you using (esi, apci, maldi, etc)? Are you sure that the
problem is the trap and not something else (ion source, filter quad,
multiplier)?
---
http://www.analyticalchem.com
Post by Murray R Darrach
Hi all,
Anyone have any insight into this phenomenon?
Titanium custom machined quadrupole ion trap that slowly over time lost the
ability to "see" polar compounds (e.g. ethyl acetate, alcohols).
Cleaning the MS with sandblasting, jewellers rouge, and solvents has not
solved the problem.
Sounds like a bit of sci-fi, but measurements don't lie.
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