> When we received our sparkling new single quad ESI-MS seven years ago
> we were overwhelmed...wow could we do stuff we had never dreamed was
possible!
> After about two years of experience we became jaded...just think what we
could
> do with more sensitivity, accuracy, resolution and if only we could
sequence
> those peptides in the map on-line!! So, we are now in the position that
we
> will be able to upgrade sometime in the forseeable future and I notice
that the
> times have changed. In the "old days" we would purchase a triple quad.
Triple
> quads now seem to be passe' and the ion trap has become the work horse.
The
> new kid on the block seems to be the orthogonal ESI/TOF. So what to
do...what
> to do? I have talked to a trusted vendor of ion traps and was told that
if we
> have the money we should buy an othogonal ESI/TOF. We have arrived at the
> subject of this email. Two vendors sell ESI/TOFs: Micromass with their
QTOF
> and QTOF2 and PE SCIEX and their QSTAR. I am convinced that both
companies
> sell instruments that we would be happy with...however there are always
pros
> and cons and I would appreciate any input regarding the following
questions:
> 1.) Most of the hype revolves around differences in resolution, 5,000
> vs 7500 vs 10,000 etc. In practical terms, is the difference between
5,000 and
> 7,500 significant...how about 5,000 vs 10,000 (I see one can pay an extra
> $100,000 for the difference).
> 2.) We are buying an instrument to do sequencing...we have no
> experience doing MS sequencing...I am told the correct software will make
or
> break us. I am told that one vendor has had excellent software for years
and
> the other has not quite released theirs yet. Should we go for the vendor
with
> the software (a bird in the hand is worth two in the bush)?
> 3.) How about the intangibles...service, support, robustness etc....
> Does one vendor stand out in these areas?
> 4.) Perhaps the ion trap vendor was being too modest and we should buy
> an ion trap??
> 5.) Finally, assuming we buy a fancy new machine should we dispose of
> our trusty old single quad? Reading the mail I see that we may want to
keep it
> so that we can continue to do the classic "Steve Carr" method of SIM
analysis
> to figure out which peak in our peptide map contains glycosylated
peptides.
>
> Weather inconsequential: the Bay area got its first significant rain for
the
> season a few days ago and I turned off the automatic sprinklers for the
back
> yard (another gopher/mole season comes to an end).
>
> Jim Bloom
> Bayer Corp
> Berkeley
> 510-705-7760
> jim.bloom.b@bayer.com
>
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