Sh. Guan et al., MS MS WITH HIGH DETECTION EFFICIENCY AND MASS RESOLVING POWER FOR PRODUCT IONS IN FOURIER-TRANSFORM ION-CYCLOTRON RESONANCE MASS-SPECTROMETRY/, Analytical chemistry, 66(8), 1994, pp. 1363-1367
We present a new ET-ICR method for MS/MS of trapped ions. Parent ions
isolated in the source trap of a dual-trap FT-ICR/MS instrument are su
bjected to off-resonance dipolar excitation to promote collision-induc
ed dissociation(CID), while product ions are simultaneously axialized
by broad-band azimuthal quadrupolar excitation in the presence of argo
n collision gas. In this way, radial diffusional loss of product ions
is greatly reduced; moreover, the axialized product ions may then be e
fficiently transferred to the analyzer trap for high-resolution detect
ion. Significant improvements in FT-ICR detection efficiency, mass res
olving power (m/Delta m greater than or equal to 20 000 at m/z less th
an or equal to 1000), and mass accuracy (less than or equal to 50 ppm
for peptide fragments of m/z less than or equal to 1000) are demonstra
ted for CID product ions of the cyclic peptide, gramicidin S.