LC ESI ION-TRAP
The new mass spectrometer is a Bruker Esquire 3000 liquid
chromatography electrospray quadrupole ion trap instrument that is
capable of performing MSn. The LC system is an Agilent Series 1100 HPLC
system with a diode array detector and automated sample injection
system. As of May 1995 we have been accepting samples for mass
analysis of molecules ranging from 500 -- `60,000 Da. The sensitivity
of our laser desorption, time of flight instrument is sub-picomole for
masses under 20,000 Da and about 10 pmol for masses larger than 20,000
Da. Our mass accuracy is within 1 AMU for molecules smaller than 5000
Da and approximately 1% for higher masses. Samples should be relatively
salt-free. The cost per analysis is $ 20.00 for single samples. Our
facility will make every effort to accommodate your needs. Please feel
free to come by and discuss your particular project and/or
problems. The Bruker was purchased to perform mass and
primary
structural analyses on proteins, peptides, oligosaccharides and organic
metabolite molecules. A number of mass analyses software programs were
purchased to assist in sample analyses. Additional software (MS
Manager) was acquired from ACD Labs for mass fragment
analysis.---inquire about costs.
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Finnigan
LaserMAT 2000
This instrument is available as a walk up instrument for all
researchers. This MALDI –TOF instrument is able to
detect
masses from 500 -50,000 Da. Masses < 500 are obscured
by the
masses of the matrix mixture. The instrument can analyze samples in the
10 pmol range with a mass accuracy of 200 ppm. This translates to about
± 1 AMU for a molecule with a mass of 5000 Da. It can be set
to
analyze either positive or negative ions. Due to the discrepancies in
the ionizability of compounds, this method cannot be used to quantify
the amounts of individual components in a mixture. Samples
are
applied to a slide that contains matrix and then placed in the
instrument. The MALDI ionization energy is considered soft and
generates only singly charged ions.
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Bruker
UltraFlex II
This instrument will be operated exclusively by Dr. Takeo Iwamoto. The
instrument is capable of operation in straight MALDI-TOF or in
MALDI-TOF/TOF modes. This feature allows one to look exclusively at
precursor ions in the TOF mode and product ions in the TOF/TOF
mode. This MALDI -TOF instrument is able to detect masses
from 10
-200,000 Da. It has a more powerful solid-state laser than
the
LaserMAT and can be modulated with respect to output wattage. A lift
cell between the two TOF sectors allows for fragmentation of molecules
thereby allowing MS/MS experiments. The instrument can analyze samples
in the 100 fmol range with a mass accuracy of 20 ppm. This translates
to about ± 0.1 AMU for a molecule with a mass of 5000 Da. It
can
be set to analyze either positive or negative ions. The MALDI
ionization energy is considered soft and generates only singly charged
ions.
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Bruker Esquire
3000 plus
This LC ESI-Ion-Trap instrument is operated primarily by Dr. Takeo
Iwamoto. We have trained a few other individuals to operate this
instrument. The instrument has both ESI and APCI ionization
methods. These methods are interchangeable. The ESI and APCI
ionization energies are harder and produce multiply charged precursor
ions. Precursor ions are accumulated in the ion trap, selected and then
fragmented to generate product ions. The product ions can be trapped
for further fragmentation. In theory this instrument can perform
MSn. We have rare need to go beyond MS3. The
instrument can
analyze samples in the 25 pg/mL range with a mass accuracy of 50 ppm.
This translates to about ± 0.25 AMU for a molecule with a
mass
of 5000 Da. The mass spec is connected to an Agilent HPLC that uses
narrow-bore columns. The LC has an autosampler for programmed sample
injections. The machine can be operated without the LC system,
introducing sample by either continual infusion or single injections.
The instrument is able to detect masses from 50 - 6,000 Da. with
analyzes for both positive and negative ions. Quantitative analyses are
possible with this instrument.
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Bruker HCT
Ultra
This instrument is an upgraded version of the Esquire 3000 plus
described above and will be operated exclusively by Dr. Takeo Iwamoto.
Sensitivity is increased more than ten-fold. The instrument
has
just ESI ionization. The ESI ionization energy generates multiply
charged ions which help extend the mass range capabilities of the
instrument The mass spec is connected to an LC-Packings Nanoflow HPLC
that uses capillary LC columns. The LC has an autosampler for
programmed sample injections. The instrument is able to detect masses
from 50 - 6,000 Da. and analyzes for both positive and negative ions.
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