A mass spectrometer includes an ion source configured to produce ions from a sample; a set of quadrupole rods configured to select ions based on a mass-to-charge ratio; a DC rod driver configured to produce a voltage; a DC rod driver filter configured to filter RF frequency interference; and a controller. The controller is configured to utilize the results of the constrained convex optimization to cause a DC rod drive to produce the DC filter input and provide a required voltage to the set of quadrupole rods, the constrained convex utilizing a impulse response curve of the DC rod driver filter to determine a DC filter input to achieve the required voltage on the set of quadrupole rods; select ions passing through the set of quadrupole rods based on the mass-to-charge ratio; and measure the intensity of the ions.

Provided is a mass spectrometer including: a measurement condition setter (42) configured to set a plurality of measurement conditions which are different from each other in terms of the set value of at least one measurement parameter; a measurement executer (43) configured to acquire a plurality of sets of mass spectrometric data respectively corresponding to the plurality of measurement conditions; a product ion extractor (44) configured to extract product ions detected with intensities exceeding a previously determined reference value; an MRM spectrum element information creator (45) configured to determine the mass-to-charge ratios and measured intensities of the extracted product ions, the mass-to-charge ratio of the precursor ion, as well as the measurement condition, and to create a plurality of pieces of MRM spectrum element information; an MRM spectrum composer (46) configured to compose an MRM spectrum from the mass-to-charge ratios and the measured intensities of the product ions included in the plurality of pieces of MRM spectrum element information; and a library data creator (47) configured to relate the MRM spectrum to information concerning the target compound to create library data for the target compound.

A mass spectrometry method comprising steps of generating an ion beam from an ion source; directing the ion beam into a collision cell; introducing into the collision cell through a gas inlet on the collision cell a charge-neutral analyte gas or reaction gas; ionizing the analyte gas or reaction gas in the collision cell by means of collisions between the analyte gas or reaction gas and the ion beam; transmitting ions from the ionized analyte gas or reaction gas from the collision cell into a mass analyzer; and mass analyzing the transmitted ions of the ionized analyte or reaction gas. The methods can be applied in isotope ratio mass spectrometry to determine the isotope abundance or isotope ratio of a reaction gas used in mass shift reactions between the gas and sample ions, to determine a corrected isotope abundance or ratio of the sample ions.

In one aspect, a method of performing mass spectrometry is disclosed, which comprises ionizing a sample to generate a plurality of precursor ions, passing the precursor ions through a mass filter to select at least one subset of the ions, introducing the selected ions into a branched radiofrequency (RF) ion trap and subjecting at least a portion of said selected precursor ions to fragmentation within the ion trap so as to generate a first plurality of fragment ions. The method can further include isolating at least a portion of the first plurality of fragment ions in at least one branch of the branched RF ion trap, removing unwanted fragment ions, releasing the remaining ions from said at least one branch and subjecting at least a portion thereof to fragmentation so as to generate a second plurality of fragment ions. Any combination of collision induced dissociation (CID) and electron activation dissociation (EAD) can be employed for fragmenting the ions.

An ion optical arrangement (1) for use in a mass spectrometer comprises electrodes (11, 12, 14) comprising a multipole arrangement defining an ion optical axis, and a voltage source for providing voltages to the electrodes to produce electric fields. The ion optical arrangement is configured for producing a radio frequency electric focusing field for focusing ions on the ion optical axis. The radio frequency electric focusing field has a varying frequency so as to reduce any mass dependence of ion trajectories through the ion optical arrangement. The ion optical arrangement may further be configured for producing a static electric field in response to a DC bias voltage applied to the multipole arrangement. A superimposed varying electric field may be produced by superimposing an AC voltage upon the DC bias voltage.

A method and device for determining an average frequency of a series of ion detection pulses (P) in a spectrometer can be applied to a measurement interval (MI). The method may comprise determining the duration of an auxiliary interval (AI1, AI2, . . . ), wherein the auxiliary interval overlaps the measurement interval, the auxiliary interval starts at the last pulse (P0) preceding the measurement interval (MI), and the auxiliary interval ends at the last pulse (PN) within the measurement interval. The method may further comprise determining the number of pulses during the auxiliary interval and dividing the number of pulses by the duration of the auxiliary interval so as to produce the average frequency. The method may be applied to a series of ion pulses produced by a voltage-to-frequency converter connected to a Faraday cup.

A mass spectrometer or ion mobility spectrometer is disclosed comprising: a first device for separating ions or molecules according to a physicochemical property (3); an ion mobility separation device (4) for receiving and separating at least some of said ions or ions derived from said molecules according to their ion mobility; a gas supply (6-10) connected to said ion mobility separation device (4) for supplying gas into said ion mobility separation device (4); and a control system (11) configured to adjust said gas supply (6-10) so as to change the composition of gas within the ion mobility separation device (4) as a function of time.

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.

A method of operating an instrument which comprises a first and second ion stores, comprising determining whether a target accumulation time for the second ion store is greater than a threshold accumulation time. When the target accumulation time is less than the threshold accumulation time, ions are accumulated within the second ion store using an accumulation time that is based on the target accumulation time. When the target accumulation time is greater than the threshold accumulation time, ions are accumulated within the first ion store using a first accumulation time that is based on a difference between the target accumulation time and the threshold accumulation time, the ions accumulated in the first ion store are passed to the second ion store, and further ions are accumulated within the second ion store using a second accumulation time that is based on the threshold accumulation time.

An ion optical arrangement (1) for use in a mass spectrometer comprises electrodes (11, 12, 14) comprising a multipole arrangement defining an ion optical axis, and a voltage source for providing voltages to the electrodes to produce electric fields. The ion optical arrangement is configured for producing a radio frequency electric focusing field for focusing ions on the ion optical axis. The radio frequency electric focusing field has a varying frequency so as to reduce any mass dependence of ion trajectories through the ion optical arrangement. The ion optical arrangement may further he configured for producing a static electric field in response to a DC bias voltage applied to the multipole arrangement. A superimposed varying electric field may be produced by superimposing an AC voltage upon the DC bias voltage.