Peter Grosshans Hitachi High Technologies America Office: 408-432-0520 FAX: 408-432-8258 E-mail: peter.grosshans@hitachi-hhta.com Job Title: Senior Manager Ph.D. in Chemical Physics from Ohio State University

Speaker: Peter Grosshans, Life Sciences Division, Hitachi High Technologies America, Parsippany, NJ 07054

Topic: The Analysis of Biomolecules by a Charge State Migration Ion Trap Mass Spectrometer

Place: Building 549, Auditorium, NCI at Frederick, Frederick, MD

Time: Tuesday, November 26, 2002, at 2:00 PM

Abstract: Recently, McLuckey et al. demonstrated that the kinetics of ion-ion reactions can be selectively controlled and inhibited with respect to mass-to-charge in electrodynamic ion traps. This "ion parking" technique may be used to purify and enrich multiply charged analytes in the gas-phase. Essentially, the entire population of ions of a protein of interest can be concentrated into a single charge state. These in-trap isolation and enrichment experiments show great promise for the characterization of low abundance proteins. Complex mixtures of proteins can be deconvolved and analyzed in the gas-phase. In addition, Charge State Migration (CSM) can be used to simplify MS/MS spectra and to determine the charge states of fragment ions (and parent ions) without the need for high-resolution mass analysis.

We have developed a mass spectrometer capable of performing CSM with the "ion parking" technology. In general, this new instrument is a modified ion trap mass analyzer, which has an atmospheric pressure-glow discharge ionization (AP-GDI) source mounted orthogonally to the ion trap to allow negative ions to enter the trap radially. The operation of the AP-GDI source is synchronized with the other MS events. Inside the trap, proton transfer reactions occur between multiply charged positive ions, formed by ESI of proteins or peptides, and singly charged negative ions generated by the glow discharge ionization of perfluorodimethylcyclohexane (PDCH). Application of various dipolar DC and RF voltages across the endcaps affords the operator a broad degree of control to purify given charge states of the peptides/proteins. This new instrument allows a more comprehensive approach to protein and peptide analyses including top-down sequencing and the more conventional bottom-up sequencing (of peptides). Data will be shown to demonstrate the concept and utility of CSM and ion parking in the analysis of protein mixtures. An overview of the system will also be presented.