Alan George Marshall

Robert O. Lawton Professor of Chemistry and Biochemistry; Chief Scientist, Ion Cyclotron Resonance Program. Coinventor of Fourier transform ion cyclotron resonance mass spectrometry (first patent), improving by orders of magnitude the speed, resolution, sensitivity, and mass range of ICR. Combined theory and experiment to develop new FT-ICR techniques. Most of the 800 plus FT-ICR systems installed worldwide since then derive from his work. Contributions include the first comprehensive theory of ICR excitation and detection, theoretically optimal (stored-waveform inverse Fourier transform (SWIFT)) excitation, also for quadrupole ion traps, theoretically optimal ion injection and trapping, ion axialization (improves ion MS/MS efficiency), and isotopic depletion (extends protein upper mass limit by 10x). Analyzed mixtures previously considered impossibly complex (e.g., petroleum crude oil, resolving and identifying more than 100,000 components and thereby creating the field of petroleomics). His approach likely the best path for next-generation top-down proteomics analysis. Publications include classic texts, Biophysical Chemistry, Principles, Techniques and Applications (1978) and Fourier Transforms in NMR, Optical, and Mass Spectrometry: A User's Handbook (1990). His lab has established performance records for broadband mass resolving power, mass resolution, and mass accuracy.