Interfacing the orbitrap mass analyzer to an electrospray ion source.
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.
Hardman
Mark
M
Thermo Masslab Ltd., Crewe Road, Wythenshawe, Manchester, M23 9BE, UK.
Makarov
Alexander A
AA
D003505:Cyclodextrins / Q000032:analysis; D004316:Doxepin / Q000032:analysis; D004917:Erythromycin / Q000032:analysis; D013058:Mass Spectrometry / Q000295:instrumentation* / Q000379:methods*; D011887:Raffinose / Q000032:analysis; D012110:Reserpine / Q000032:analysis; D012680:Sensitivity and Specificity; D055672:Static Electricity; D047392:beta-Cyclodextrins
D003505:Cyclodextrins; D047392:beta-Cyclodextrins; D004316:Doxepin; D004917:Erythromycin; D012110:Reserpine; C031215:betadex; D011887:Raffinose