Interfacing the orbitrap mass analyzer to an electrospray ion source

Anal Chem. 2003 Apr 1;75(7):1699-705. doi: 10.1021/ac0258047.


The orbitrap mass analyzer employs the trapping of pulsed ion beams in an electrostatic quadro-logarithmic field. This field is created between an axial central electrode and a coaxial outer electrode. Stable ion trajectories combine rotation around the central electrode with harmonic oscillations along it. The frequencies of axial oscillations and hence mass-to-charge ratios of ions are obtained using fast Fourier transform of the image current detected on the two split halves of the outer electrode. This work proves that such a trap could be coupled to a continuous, electrospray, ion source. Such a coupling necessitated the development of an rf-only quadrupole for external accumulation of ions and their injection in very short (< 1 micros) ion bunches. Along with good sensitivity, this mass spectrometer provides mass resolving power up to 150,000 fwhm, mass accuracies within a few parts per million, and relative mass range up to 8-fold. The maximum number of ions available for analysis is limited by the space-charge capacity of the accumulation quadrupole.

MeSH terms

  • Cyclodextrins / analysis
  • Doxepin / analysis
  • Erythromycin / analysis
  • Mass Spectrometry / instrumentation*
  • Mass Spectrometry / methods*
  • Raffinose / analysis
  • Reserpine / analysis
  • Sensitivity and Specificity
  • Static Electricity
  • beta-Cyclodextrins*


  • Cyclodextrins
  • beta-Cyclodextrins
  • Doxepin
  • Erythromycin
  • Reserpine
  • betadex
  • Raffinose