Matt has covered the bases on Ultramark calibration very well. I have just a
few additions.
Finnigan has a small cap for the end of the heated capillary that minimizes
the amount of cal solution that is sprayed on the PEEK bushing around the
heated capillary. This is called the Keqi Cap and is Finnigan P/N
97000-20347.
Use this only during calibration.
After calibration, use a squirt bottle to liberally spray HPLC grade acetone
on the end of the heated capillary, the PEEK bushing and the rest of the
spray shield area. Acetone has a low viscosity, which allows access to the
gaps where the Ultramark hides. I believe that this the source of most of
the Ultramark contamination problem.
If you are performing data dependent scans be sure to include the Ultramark
masses in the Reject List.
Regarding Dan Kirby's comment on the Electron Multiplier calibration routine
not working correctly with nanospray:
I am trying to find another way to do this.
Bill Mahn
ThermoQuest Technical Support
----- Original Message -----
From: MSweeney <mattsweeney@earthlink.net>
To: Recipients of ABRF List <abrf@aecom.yu.edu>
Sent: Wednesday, November 10, 1999 7:04 PM
Subject: Re: LCQ Calibration
>
> Tom-
>
> That IS a hassle.
>
> Here are my tips.
>
> 1)I have utilized a separate syringe and transfer silica line dedicated
for
> ultramark. That helps.
>
> 2)The ESI probe is another source of contamination. For this I have used
an
> acn:meoh 1:1 mix. Mehdi Moini's (first ref on esi ultramark in jams)
paper
> mentions this mix. Perhaps there are better ones. I have another
> syringe/transfer line for the acn:meoh which I attach to the grounding
union
> and pump several syringe full while the source is on. Then I attach the
> solution to the sheath liquid input and pump some more through here. This
> is because some ultramark lurks in the inter silica/needle space where the
> sheath liquid passes. Then I attach the N2 from the aux gas line to the
> sheath liquid input and blow that area DRY!!!. Then if you want you go to
> step 3) . Or rinse the sample input once more with the 1:1 and then go.
> But first I turn off the ESI and do the next step. Another thing is to
> replace the ESI silica after a tune. I always like to have giant rolls
of
> that stuff around anyway. Polymicro Technologies sells it among others.
> Pull the silica out the needle end though.
>
> 3)I have found that the peek sleeve around the heated cap. is one other
> source for contamination (in addition to the spray shield). I direct
the
> acn:meoh at the crannies around the peek sleeve and at the shield itself.
I
> remove the ESI probe and then do this for better access. I also use
> kemwipes here.
>
> 4)Then put it back together and go.
>
> The LCQ has had that tune solution "hard wired" into its code (unlike the
> xsq insts). Trusting the guys at Finnigan to write code that tunes my
trap
> has always worked for me. On the up side those ultramark spikes make
great
> internal calibrations available to you!! The lcq has the ability to let
you
> do a 2 point cal correction to the existent tune file as a kind of short
> term cal. correction so as to let you put off re-"Ultramarking" the
system.
> I have sometimes dedicated an ESI probe to Ultramark tunes so as to avoid
> having to do the probe rinse step. Not everyone has that luxury.
>
> If anyone has any comments about this that don't jibe with this let me
know.
> I'd love to hear.
>
> Matt Sweeney
> mattsweeney@earthlink.net
> Mass Spec Consulting
> Training/Operations/Consulting/Method Development
> LC/MS Pharmacokinetics, Peptides, Proteins, Metabolism,
> Maintenance Classes, Specialist in Finnigan Equipment and Software
>
======================================
>
In response to the question from Thomas D. McClure, to the best of my
knowledge it's still the case that Ultramark must be used to do the
calibration because those specific ions are required by the calibration
program. One way around the problem of Ultramark residue is to do the
calibration by nanospray. This works for all parameters except em gain.
There's something about the s/n of the nanospray signal and how the program
does em calibration that makes this unreliable. So, if you don't have to
calibrate em gain, you can do the whole calibration with a uL or two of the
SOP solution and little or no cleanup is necessary. Use the suggested
infusion method for em gain only using the heated capillary shield that
Finnigan passed out a while ago.
Dan
_______________________
Dan Kirby
Praecis Pharmaceuticals
1 Hampshire Street
Cambridge, MA 02139
dan.kirby@praecis.com
<http://www.praecis.com>
>
>
> >To: Recipients of ABRF List <abrf@aecom.yu.edu>
> >cc:
> >Subject: LCQ Calibration
> >
> >A question for those of you who have LCQ mass spectrometers. Has anyone
> devised
> >a cleaner calibration mixture for the LCQ--one not using Ultramark? We
are
> >finding that we spending a significant amount of time cleaning the
> instrument
> >after running the calibration mixture as prescribed by the vendor.
> >
> >Thanks in advance,
> >Tom McClure
> >-------------------------------------------------------
> >
> >
> >
>
>