The major goal has been to develop a matrix-assisted laser desorption/ionization (MALDI) quadrupole ion trap (QIT) as a high performance tandem mass spectrometer for the amino acid sequencing of peptides from complex biological mixtures. High performance characteristics include high sensitivity, high mass accuracy, unit mass resolution in both MS and MS/MS modes, unit mass selection in tandem experiments, efficient collisional activation, and the ability to record wide mass ranges (multichannel advantage) in each cycle. During the past three years a novel method has been developed for efficiently trapping MALDI ions that ramps the fundamental RF voltage as the ions enter the trap, a method for modulating the supplementary RF voltage during mass scans that provides high linearity and mass accuracy, broadband and stretched in time SWIFT techniques for monoisotopic mass selection and isolation, and pulsed heavy gas introduction during excitation that enables one to lower the low mass cutoff for recording a wider range of product ion masses. It is now proposed to expand this effort by the addition of a reflectron time-of-flight (reTOF) mass analyzer. Current QIT/TOF configurations provide (primarily) a means for interfacing continuous ionization methods (e.g. electrospray) to the TOF analyzer, but do not exploit the high performance characteristics of the QIT. In the proposed instrument, the reTOF would serve first as a rapid, multichannel recording device for ions collisionally activated in the trap. Additionally, it would provide the ability to carry out high-energycollisions for ions mass-selected in the trap, with multichannel recording achieved using a curved -field reflectron. Finally, the investigator will also develop a high mass MALDI QIT/reTOF instrument from rapid sequencing of DNA oligomers in the mass range of 5,000 to 20,000 daltons, using a fundamental RF supply that is continuously variable with respect to both frequency and amplitude.

Agency
National Institute of Health (NIH)
Institute
National Center for Research Resources (NCRR)
Type
Research Project (R01)
Project #
5R01RR008912-05
Application #
2635830
Study Section
Metallobiochemistry Study Section (BMT)
Project Start
1994-01-01
Project End
2000-12-31
Budget Start
1998-01-01
Budget End
1998-12-31
Support Year
5
Fiscal Year
1998
Total Cost
Indirect Cost
Name
Johns Hopkins University
Department
Pharmacology
Type
Schools of Medicine
DUNS #
045911138
City
Baltimore
State
MD
Country
United States
Zip Code
21218
Smit, John; Kaltashov, Igor A; Kaltoshov, Igor A et al. (2008) Structure of a novel lipid A obtained from the lipopolysaccharide of Caulobacter crescentus. Innate Immun 14:25-37
Laiko, V V; Moyer, S C; Cotter, R J (2000) Atmospheric pressure MALDI/ion trap mass spectrometry. Anal Chem 72:5239-43
Doroshenko, V M; Cotter, R J (1999) Ideal velocity focusing in a reflectron time-of-flight mass spectrometer. J Am Soc Mass Spectrom 10:992-9
Doroshenko, V M; Cotter, R J (1998) A quadrupole ion trap/time-of-flight mass spectrometer with a parabolic reflectron. J Mass Spectrom 33:305-18
Kaltashov, I A; Doroshenko, V; Cotter, R J et al. (1997) Confirmation of the structure of lipid A derived from the lipopolysaccharide of Rhodobacter sphaeroides by a combination of MALDI, LSIMS, and tandem mass spectrometry. Anal Chem 69:2317-22
Kaltashov, I A; Doroshenko, V M; Cotter, R J (1997) Gas phase hydrogen/deuterium exchange reactions of peptide ions in a quadrupole ion trap mass spectrometer. Proteins 28:53-8
Doroshenko, V M; Cotter, R J (1997) Injection of externally generated ions into an increasing trapping field of a quadrupole ion trap mass spectrometer. J Mass Spectrom 32:602-15
Doroshenko, V M; Cotter, R J (1996) Advanced stored waveform inverse Fourier transform technique for a matrix-assisted laser desorption/ionization quadrupole ion trap mass spectrometer. Rapid Commun Mass Spectrom 10:65-73
Doroshenko, V M; Cotter, R J (1996) Effect of phase locking AC and RF voltages for high mass analysis in a quadrupole ion trap mass spectrometer. Rapid Commun Mass Spectrom 10:1921-6
Doroshenko, V M; Cotter, R J (1995) High-performance collision-induced dissociation of peptide ions formed by matrix-assisted laser desorption/ionization in a quadrupole ion trap mass spectrometer. Anal Chem 67:2180-7

Showing the most recent 10 out of 11 publications