A. N. Verenchikov
Institute for Analytical Instrumentation RAS, Saint-Petersburg
To increase the speed and sensitivity
of the tandem mass spectrometric MS-MS analysis, a tandem of two time-of-flight
analyzers (TOFA) is proposed to be used in a novel mode of "nested times":
slow separation of parent ions in the first analyzer occurs on the millisecond
time scale while fast fragmentation and rapid mass analysis of the fragments
in the second analyzer --- on the microsecond scale. The nested time mode
allows a so called "parallel analysis" of fragment spectra for all parent
ions within a single separation cycle of TOFA1. "Slow" TOFA of a new type
are introduced to implement this method. They combine transverse confinement
of an ion beam with high-order time-of-flight energy focusing. Radiofrequency
(RF) or periodic electrostatic fields are suggested to achieve the transverse
confinement. The paper presents performance analysis of the key tandem
components including a "slow" TOFA, ion source with an ion storage, and
a fragment cell with fast ion transmission.