Mass Spectrometry is a rapidly advancing scientific discipline with tremendous
employmentopportunities. Our aim is to provide most up-to-date teaching
and frontier-level research programs to our students.
Our courses are intended for novices who would like to gain experience with
mass spectrometry, as well as for experienced researchers who wish to learn
the latest developments in this field. Computer based animations created
at Stevens help students to understand complex ion formation and transfer
optics that occur inside mass spectrometers.
Many agree that Center for Mass Spectrometry at Stevens is one of the well-equipped
academic facilities in the U.S. With six mass analyzers incorporating time-of-flight
and quadrupolar techniques, and a variety of inlets such as electrospray,
MALDI, ApCI, EI and CI, the Center undoubtedly lives up to the second-to-none
motto of the Imperatore School. The center welcomes collaborative research
projects from Stevens community and outside. Samples can also be analyzed
on a fee-for-service basis. Our instruments are amenable to a wide
variety of organic compounds including proteins, peptides, amino acids, alkaloids,
steroids, flavanoides, saccharides, lipids, nucleic acids, polymers, petroleum
products, and organo-metallics. Our mass analyzers are based on time-of-flight
and quadrupolar techniques. Some of our instruments are able
to detect both positive and negative ions, carry out tandem mass spectrometry
experiments, and provide accurate mass data.
Contact Information
Center for Mass Spectrometry is located
in fourth floor of McLean Building for Chemical Sciences.
Mass Spectrometric Fragmentation Mechanisms
Chemical Ecology of Arthropods
Biosynthesis
Natural Products
Drugs from Bugs
Which Ionization Technique?
Electron impact ionization (EI). The classical ionization technique for
small molecules. This technique is applicable only to thermally stable
compounds since
the sample should be vaporized by heating. An EI spectrum shows many peaks
for fragment-ions derived from the molecular ion. Although an EI spectrum
might not
always show a molecular peak, it is useful for structural characterization
and identification of compounds. The spectra obtained in this way can
be matched
with those in our computer database (over 350,000 spectra).
Chemical ionization (CI). A reagent gas is first ionized and allowed to
collide with the sample. We can run samples with methane, ammonia, and isobutane
as the reagent gas on both Quattro and HP Mass Engine instruments. You may discuss
with facility personnel if you need other reagent gases.
Electrospray ionization (ESI). This is the method of choice for polar
natural and synthetic compounds, proteins, oligonucleotides and organometallic
complexes. However, the sample must generally be soluble and stable
in a solvent such
as water, acetonitrile, or methanol.
MALDI. The method of choice for somewhat hydrophobic, large molecular weight
compounds. The sample is mixed with a UV absorbing matrix and irradiated
with a laser beam to desorb ions into gas phase.
Fast atom bombardment ionization (FAB). This is a soft ionization
technique that was useful for heat-sensitive, nonvolatile compounds.
A spectrum
obtained under
positive ion conditions could show a few peaks for fragments and
an intense signal for the pseudomolecular ion produce by protonation(M+H)
or cationization.
Although
we do not offer this ionization technique, nearly all FAB-type
samples can be examined by electrospray, APCI, or MALDI methods.
Radioactive samples
Our facility is not authorized to handle any radioactive samples.
Acknowledgments
Please acknowledge
in your publications the use of Center for Mass Spectrometry
instrumentation. A statement such as "High resolution mass spectra (or any other technique
as appropriate) were obtained in the Center for Mass Spectrometry of Department
of Chemistry and Chemical Biology of Stevens Institute of Technology,” would
be appropriate.
Last revised: August, 2004
Stevens Institute of Technology • Hoboken, NJ • (201) 216-5000