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 zwitterion formation in amino acids. Most recently, we have added a broadly tunable infrared laser system that enables us to use spectroscopy to directly probe hydrogen bonding in hydrated clusters.

Selected Articles:

• 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 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 (FAIMS). 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.

Quadrupole Mass Spectrometer

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