Certain configurations of a stable capacitor are described which comprise electrodes produced from materials comprising a selected coefficient of thermal expansion to enhance stability. The electrodes can be spaced from each other through one of more dielectric layers or portions thereof. In some instances, the electrodes comprise integral materials and do not include any thin films. The capacitors can be used, for example, in feedback circuits, radio frequency generators and other devices used with mass filters and/or mass spectrometry devices.

A system and method is described for characterizing glycopeptides which includes a first quadrupole mass filter, a multipole rod set of an ion guide, a lens electrode, an ExD device and a mass analyzer. The multipole rod set is adapted to receive a radial radio frequency (RF) trapping voltage and a radial dipole direct current (DC) voltage The lens electrode is adapted to receive an axial trapping alternating current (AC) voltage and a DC voltage. The ExD device performs electron capture dissociation or electron transfer dissociation, the ExD device being positioned so that an entrance of the ExD device is disposed on the other side of the lens electrode opposite the multipole rod set. The mass analyzer is positioned at an exit of the ExD device for receiving ions from the ExD device.

Certain configurations of ionization sources are described. In some examples, an ionization source comprises an ionization block, an electron source, an electron collector, an ion repeller and at least one electrode configured to provide an electric field when a voltage is provided to the at least one electrode. Systems and methods using the ionization source are also described.

The present inventive concepts relate to determining an isotope ratio using mass spectrometry. Mass spectra of ions are obtained by generating ions, guiding the ions through a device having a mass transfer function that varies with ion current, providing at least some of the ions to a mass analyser and obtaining a mass spectrum of the ions and determining the ion current of the ions provided to the mass analyser. An isotope ratio of the ions is determined for each mass spectrum. Using the determined isotope ratio and determined ion current for each mass spectrum, a calibration relationship is determined that characterises the variation of the determined isotope ratios and the measured ion currents across the mass spectra. Then, a measured isotope ratio obtained at a determined ion current is adjusted using the calibration relationship to adjust the measured isotope ratio to an adjusted isotope ratio corresponding to a selected ion current.

A mass spectrometer includes a collision cell and a system controller. The collision cell includes a plurality of rod pairs configured to generate pseudopotential well through the application of radio frequency potentials to the rod pairs. The collision cell configured to generate a target fragment from a parent ion by colliding the parent ion with one or more gas molecules. The system controller is configured to set a radio frequency amplitude of the radio frequency potentials to a default amplitude; monitor the production of a target fragment ion while adjusting the collision energy; set the collision energy to optimize the production of the target fragment ion; apply a linear full range ramp to the radio frequency amplitude to determine an optimal radio frequency amplitude; and set the radio frequency amplitude to the optimal radio frequency amplitude for the parent ion, target fragment ion pair.

A method of mass spectrometry is disclosed comprising separating precursor ions using an ion mobility separator such that different precursor ions have different drift times through the on mobility separator; mass filtering said separated precursor ions with a mass filter, wherein the mass to charge ratios of the precursor ions transmitted by the mass filter vary as a function of the drift times of the precursor ions through the ion mobility separator; performing a first mode of operation comprising fragmenting the separated and mass filtered precursor ions in a fragmentation device to form fragment ions; urging the fragment ions through the fragmentation device such that fragment ions derived from different precursor ions that have been separated by the ion mobility separator are maintained spatially separated from each other as they are urged through the fragmentation device; and detecting the fragment ions. The method enables precursor ions to be associated with their related fragment ions more accurately.

A mass spectrometer or ion mobility spectrometer is disclosed comprising: a first device for separating ions or molecules according to a physicochemical property; an ion mobility separation device for receiving and separating at least some of said ions or ions derived from said molecules according to their ion mobility; a gas supply connected to said ion mobility separation device for supplying gas into said ion mobility separation device; and a control system configured to adjust said gas supply so as to change the composition of gas within the ion mobility separation device as a function of time.

A method for parallel accumulation and serial fragmentation of ions, wherein ions are injected into a device capable of serial ejection using a pseudopotential barrier created by an RF voltage. In all instances, the ions may be filtered prior to accumulation in the device capable of serial ejection. In some cases this filtering may take the form of discrete isolation windows using isolation waveforms with multiple notches. In some cases these waveforms may be applied to a quadrupole mass filter. Following accumulation of the precursor ions, the initial population may be serially ejected using a pseudopotential barrier created by an RF voltage. Following serial ejection, the individual precursor ion populations are analyzed. In some cases, this analysis might involve additional rounds of ion isolation and manipulation (e.g., MSn, CID, ETD, etc.).

An ion filter for a mass spectrometer, the apparatus comprising an ion modifier; an ion selector configured to select a subset of a sample of ions based on their mobility in a gas; and a controller configured to operate the ion modifier in a first mode to modify the ions selected by the ion selector to provide daughter ions, and configured to operate the ion modifier in a second mode to output the ions selected by the ion selector; wherein the ion filter is adapted for providing output ions from the ion modifier to an intake of a mass spectrometer.

An ion manipulation device is disclosed comprising: an ion receiving region (30) for receiving ions; a pair of electrodes (14,16) adjacent the ion receiving region (30); and an AC or RF voltage supply (18) arranged to apply an AC or RF voltage to said electrodes (14,16), or arranged and configured to generate an electromagnetic field that couples to said electrodes (14,16) in use, such that an electromagnetic standing wave (24) is generated between said electrodes (14,16). A first of the electrodes (14) comprises one or more apertures through which an electric field from the standing wave (24) penetrates and enters the ion receiving region (30), in use, for urging said ions away from the one or more apertures.