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Realised by ALMS™
developer of the AIDS-HIV Reference project
Abstract No.: TuP-113
Session: Gas Phase Ion Chemistry
Presentation date: Tue, Aug 29, 2006
Presentation time: 09:50 – 11:20

A Novel Electrospray Selected-ion Flow Tube Tandem Mass Spectrometer Suited for Biophysical Chemistry

Gregory K. Koyanagi1, Janna Anichina1, Andrea Dasic1, Diethard K. Bohme1

1 Department of Chemistry and CRMS, York University, Toronto, Canada

Correspondence address: Greg K. Koyanagi, York University, Chemistry, 4700 Keele Street, Toronto, M3J 1P3 Canada.

Keywords: Electrospray Ionization (ESI); Ion Reactivity; Reaction, Ion/Molecule; Selected Ion Flow Tube.

Novel aspect: A SIFT apparatus has been fitted with an ES ion source, an ion guide reaction cell, and a triple quadrupole mass spectrometer to provide a powerful and versatile means to investigate the kinetics and energetics of reactions of biological ions.

 

We have greatly expanded the capabilities of our flow tube technique by incorporating three significant new features. Firstly, we have fitted an electrospray ion source prior to the up-stream ion selection quadrupole. Also, we have incorporated a radio-frequency ion guide reaction region immediately after the electrospray source. Finally, a triple quadrupole mass spectrometer (extended mass range) has been added after the flow tube. This new configuration symbolized as an ES/(QRC)Q/SIFT/Q(QCC)Q mass spectrometer provides a powerful and versatile means to investigate the kinetics and energetics of reactions of biological ions. Further, the flow tube serves as an excellent source of mono-energetic ions, critical in determining onset energies for collision-induced dissociation.

Earlier instruments developed in this vein suffered from complications associated with a lack of pre-selection and the resulting lack of definition of charge state distributions, isotope distributions, and solvation. The ES interface in our instrument permits desolvation of electrosprayed ions. Moreover, this desolvation region can be used to fragment weakly bonded ions, further extending the diversity of reactant ions generated by the ES source. Mass selection prior to entering the flow tube removes complications due to charge state distributions and can ameliorate complications due to isotope distributions.

Here we report first results to illustrate the power of the extended flow tube instrument. The CID functionality of the down-stream tandem MS analyser has been calibrated by studying the energy resolved dissociation of the N-benzylquininium cation (a quaternary ammonium ion). Dissociation onsets are sufficiently sharp to permit the determination of physically significant bond dissociation energies. The kinetics of bradykinin H/D exchange with CH3OD has been studied and our results are consistent with those reported previously. The iron(III) Bleomycin A2 cation has been created in solution and injected into the flow tube. Attempts to create in the flow tube for subsequent bio-physical study the corresponding hydroperoxicomplex that is believed to be one of the active forms of Bleomycin required for anti-tumor activity show encouraging results.

Also, low-mass metal cations (Ca, Mg, Al), and anions of all sizes have been generated by the ES source, complimenting our previously used plasma ion source, which had limited sensitivity below 40 amu and produced (with few exceptions) only positive atomic ions.