Williams Group
Instruments
2.7 T Ion Cyclotron
Resonance Mass Spectrometer
The Berkeley 2.7 T FT-ICR is used primarily to study the
physical chemistry of small, non-covalently bound clusters in the gas
phase. This home-built instrument is equipped with a very gentle
nanoelectrospray ion source that can preserve non-covalent interactions
present in solution. Ions are exposed to the blackbody field generated
by the instrument, which can be varied from ~80 K to 500 K. This
enables many kinetic studies and allows the study of clusters with
temperature dependent structures. We have used this instrument to probe
many aspects of spectroscopy to
directly probe hydrogen bonding in hydrated clusters.
Description
of ion cell: Wong,
R. L., Paech, K. and Williams, E. R. Blackbody
Infrared Radiative Dissociation at Low Temperature: Hydration of X2+(H2O)n,
for X = Mg, Ca. International
Journal of Mass Spectrometry. 2004,
232, 59-66.web
Description of electrospray
interface: Bush, M.
F., Saykally, R. J. and Williams, E. R.
Formation of Hydrated
Triply Charged Metal Ions from Aqueous Solutions using Nanodrop Mass
Spectrometry. International
Journal of Mass Spectrometry. 2006,
252, 256-262.
web
Description of instrument and
experimental methods: Bush, M. F.,
O'Brien, J. T.,
Prell, J. S., Saykally, R. J. and Williams, E. R. Infrared
Spectroscopy of Cationized Arginine in the Gas Phase: Direct Evidence
for the Transition from Nonzwitterionic to Zwitterionic Structure.
Journal of the American Chemical
Society. 2007,
129, 1612-1622. web
9.4 T Ion Cyclotron Resonance Mass Spectrometer
The Berkeley-Bruker 9.4 T FT-ICR is the primary platform for
large biomolecule and polymer studies in the Williams Lab. It has been
heavily modified to incorporate extensive MSn
capabilities, including various dissociation techniques,
gas-phase chemistry such as H/D exchange, as well as conformational
selection tools such as high field asymmetric waveform ion mobility
spectrometry.
Although nano-electrospray ionization (nESI) has traditionally been
used in Williams Lab, recently we have added a custom-built desorption
electrospray (DESI) source to the instrument to further our analytical
capabilities.
Description of instrument: Jurchen, J. C. and
Williams,
E. R. Origin of asymmetric
charge partitioning in the dissociation of gas-phase protein homodimers.
Journal of the American Chemical
Society. 2003,
125, 2817-2826.
web
