摘要:
The invention relates to methods and devices for regulating the filling level in measuring cells of ion cyclotron resonance mass spectrometers so that it is optimal for mass resolution and mass accuracy. The invention consists in supplying a fraction of the samples to a second reference mass spectrometer operated in parallel, and employing the mass spectra obtained from this reference mass spectrometer to regulate the filling level in the ion cyclotron resonance mass spectrometer.
摘要:
An ion cell having an axis includes a sheath of individual electrodes that extends along the axis and defines an internal volume. Adjacent individual electrodes are electrically insulated from each other. The individual electrodes each receive a DC potential and RF voltage. At least some of the individual electrodes have a width that varies in the axial direction such that an electrical effect on an axis potential varies along the axis of the ion cell.
摘要:
The invention relates to a method and a device for controlling the number of ions in ion cyclotron resonance (ICR) mass spectrometers, whereby the ions enter a multipole ion guide after their formation and are stored there temporarily. By measuring the ion number in a predefined subset of these temporarily stored ions, the number of ions transferred into the ICR trap for mass spectrometric analysis is regulated. A mode of operation of the multipole ion guide can ensure that undesirable mass ranges are filtered out before the transfer of ions into the ICR mass spectrometer. The invention makes it possible to eliminate space charge effects, which are caused by overfilling the ICR traps.
摘要:
Ion mobilities are measured by entraining the ions in a gas and adiabatically expanding the ion-containing gas through a nozzle to form a gas jet. An electrical field barrier with variable height is located at the nozzle exit. The field barrier may be located adjacent to the nozzle exit or an ion guide may be located between the nozzle and the field barrier. If a continuous ion current is supplied, the height of the barrier is varied and the ion current of the ions passing over the barrier is measured, the ion current can be differentiated to generate a mobility spectrum. Alternatively, the ions can be temporarily stored in the ion guide so that measurement of the ion current of the ions passing over the barrier results in a direct measurement of the mobility spectrum.
摘要:
The mobility of mass-selected ions in gases is measured at pressures of a few hectopascal by selecting the ions under investigation in a quadrupole filter according to their mass-to-charge ratio m/z, measuring their mobility in a drift region at a pressure of a few hundred Pascal under the influence of a DC electric field and then filtering the measured ions by means of a quadrupole field in order to eliminate, or detect changes in, the mass-to-charge ratio. Several embodiments for the drift region are disclosed, in which the ions are kept in the axis of the drift region by RF fields. As these drift regions can also be utilized for a collision-induced decomposition of the ions, the device can additionally be used as a so-called triple quadrupole mass spectrometer.
摘要:
The invention relates to instruments for storing ions in more than one ion storage device and to the use of the storage bank thus created. The ion storage bank includes several storage cells configured as RF multipole rod systems, where the cells contain damping gas and are arranged in parallel. Each pair of pole rods is used jointly by two immediately adjacent storage cells such that the ions collected can be transported from one storage cell to the next by briefly applying DC or AC voltages to individual pairs of pole rods. The ions can thus be transported to storage cells in which they are fragmented or reactively modified, or from which they can be fed to other spectrometers. In particular, a circular arrangement of the storage cells on a virtual cylindrical surface makes it possible to accumulatively fill the storage cells with ions of specific fractions from temporally sequenced separation runs.
摘要:
Ion mobilities are measured by entraining the ions in a gas and adiabatically expanding the ion-containing gas through a nozzle to form a gas jet. An electrical field barrier with variable height is located at the nozzle exit. The field barrier may be located adjacent to the nozzle exit or an ion guide may be located between the nozzle and the field barrier. If a continuous ion current is supplied, the height of the barrier is varied and the ion current of the ions passing over the barrier is measured, the ion current can be differentiated to generate a mobility spectrum. Alternatively, the ions can be temporarily stored in the ion guide so that measurement of the ion current of the ions passing over the barrier results in a direct measurement of the mobility spectrum.
摘要:
An ion cell having an axis includes a sheath of individual electrodes that extends along the axis and defines an internal volume. Adjacent individual electrodes are electrically insulated from each other. The individual electrodes each receive a DC potential and RF voltage. At least some of the individual electrodes have a width that varies in the axial direction such that an electrical effect on an axis potential varies along the axis of the ion cell.
摘要:
The invention relates to methods and devices for regulating the filling level in measuring cells of ion cyclotron resonance mass spectrometers so that it is optimal for mass resolution and mass accuracy. The invention consists in supplying a fraction of the samples to a second reference mass spectrometer operated in parallel, and employing the mass spectra obtained from this reference mass spectrometer to regulate the filling level in the ion cyclotron resonance mass spectrometer.
摘要:
In a Kingdon ion trap in which harmonic ion oscillation in a potential well in a longitudinal direction is completely decoupled from ion oscillation in a direction transverse to the longitudinal direction, ions enter the trap via an entrance tube extending through, but electrically insulated from, one of the Kingdon trap housing electrodes and located outside the minimum of the potential well in the longitudinal direction. The geometry of the Kingdon trap is arranged so that the oscillating ions introduced through the entrance tube cannot return to the entrance tube until they have performed several longitudinal oscillations during which time heavy ions can be introduced into the trap.