High-resolution ion isolation with the ion cyclotron resonance capacitively coupled open cell.
For ion cyclotron resonance, a capacitively coupled open cell variant with fourfold radial symmetry was constructed and tested for axial excitation-ejection of large ions at high resolution. With a reverse of frequency sweep direction, this cell gave substantial improvements in signal-to-noise ratio due to linearization of the excitation electric field. Single isotopic peaks of ubiquitin (8.6-kDa) and carbonic anhydrase (29-kDa) molecular ions could be isolated by selective stored waveform inverse Fourier transform excitation, which yielded an order of magnitude higher isolation resolving power than previously achieved at high mass-to-charge ratio values.
Department of Chemistry, Cornell University, Ithaca, New York, USA.
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O'Connor
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McLafferty