Professor, Chemistry
School of Physical Sciences

Physical and Analytical Chemistry

www.chem.uci.edu/people/faculty/rmciver/

Regents Faculty Research Awardee
Alfred P. Sloan Fellow
UCI Distinguished Teaching Awardee

Our research utilizes a powerful new analytical method called Fourier Transform Mass Spectrometry (FTMS) to study a wide variety of chemical systems. Three FTMS instruments have been built at UCI during the last few years, and each is specially designed for a particular purpose.

The most powerful FTMS instrument utilizes a 70,000 Gauss super-conducting magnet to investigate the ionization and fragmentation of high-mass biomolecules. Peptides having molecular weights as high as 6,000 can be analyzed with this instrument. Molecular ions of the peptide are generated by bombarding the sample with a high-energy beam of cesium ions. The peptide ions are focused into a beam and injected into the FTMS instrument for mass analysis. We are particularly interested in developing new methods for elucidating the structures of high molecular weight biomolecules. One promising new method utilizes a powerful laser to fragment the ions while they are stored in the FTMS analyzer cell.

Another of our FTMS instruments has been designed to study chemical reactions occurring on well-characterized metal surfaces. The aim of the research is to study the kinetics of surface reactions and to observe reaction intermediates directly. Single-crystal metal surfaces are cleaned and annealed in an ultra-high vacuum chamber having a base pressure of less than 1E-10 Torr. The composition and integrity of the surface is determined by Auger Electron Spectroscopy (AES) and Low- Energy Electron Diffraction (LEED). The clean surface is then exposed to a reactant that adsorbs onto the surface. After a certain reaction period, a pulsed laser is fired at a small spot on the surface, and in just 20 ns the temperature of the surface increases by 1,000 ¡C. Such rapid heating causes molecules on the surface to desorb immediately, and as they leave the surface, they are ionized and detected by FTMS. We are using this laser-desorption FTMS instrument to study the kinetics of hydrocarbon dehydrogenation on transition-metal surfaces and the decomposition of methanol on platinum.

A third FTMS instrument is being used to identify trace amounts of molecular species which are adsorbed on surfaces. Most surface analytical techniques, such as Low-Energy Electron Diffraction (LEED) and X-ray photoelectron spectroscopy (XPS), reveal very little about the molecular identity of an adsorbate. However, the laser desorption FTMS method described above has been very successful at identifying trace surface contaminates such as lubricants on the surface of a computer magnetic hard disk.

High-Accuracy Molecular Mass Determination for Peptides and Proteins
by Fourier Transform Mass Spectrometry. Analytical Chemistry
1994, 66, 13. Y. Li, R. T. McIver, Jr., R. L. Hunter.

Matrix-assisted Laser Desorption/Ionization with an External Ion
Source Fourier-transform Mass Spectrometer.
Rapid Communication in Mass Spectrometry 1994,
8, 237. R. T. McIver, Jr., Y. Li, R. L. Hunter.

Detection Limits for Matrix-assisted Laser Desorption of
Polypeptides with an External Ion Source
Fourier-transform Mass Spectrometer.
Rapid Communication in Mass Spectrometry 1994,
8, 743. Y. Li, R. T. McIver, Jr.

High-resolution Laser Desorption Mass Spectrometry of
Peptides and Small Proteins.
Proceedings National Academy Sciences, USA
May 1994, 91, 4801. R. T. McIver, Jr., Y. Li, R. L. Hunter.

Kinetic Study of the Initial Stages of Dehydrogenation of
Cyclohexane on the Pt. (111) Surface.
Journal of Physical Chemistry 1992, 96, 1888.
D. H. Parker, C. Pettitte-Hall, Y. Li, R. T. McIver, Jr., J. C. Hemminger.

Link to this profile
https://faculty.uci.edu/profile/?facultyId=2730

Last updated
03/15/2002