A method of isotope ratio mass spectrometry comprising: flowing a liquid mobile phase through a separation device; reducing the flow rate of the mobile phase through the separation device for at least a portion of time that at least one molecular species is emerging from the separation device to achieve a desired isotope ratio precision, wherein the flow rate is reduced from a first rate to a second rate corresponding to a higher theoretical plate height of the separation device; and mass analyzing the molecular species that has emerged from the separation device at least while the flow rate is reduced; and determining at least one isotope ratio from the intensities of mass peaks of at least two isotopologues, wherein the mass analysis is performed with mass resolving power high enough to resolve the two most abundant mass peaks at the nominal mass of at least one of the isotopologues.

An isotope mass spectrometer including: an electron cyclotron resonance ion source, a front-end analysis device, a back-end analysis device and an ion detector; where the electron cyclotron resonance ion source is connected with the front-end analysis device, and is used for generating ion beams of multivalent charge states; the front-end analysis device is connected with the back-end analysis device, selects and separates the ion beams, and receives ion beams of constant, microscale and trace levels; the back-end analysis device is connected with the ion detector, and is used for eliminating a background of an isotope to be measured at an ultratrace level; and the ion detector is used for receiving ion beams of the ultratrace level, and carrying out energy measurement and separation on the ion beams of the ultratrace level, so as to obtain the isotope to be measured at the ultratrace level.

An isotope mass spectrometer including: an electron cyclotron resonance ion source, a front-end analysis device, a back-end analysis device and an ion detector; where the electron cyclotron resonance ion source is connected with the front-end analysis device, and is used for generating ion beams of multivalent charge states; the front-end analysis device is connected with the back-end analysis device, selects and separates the ion beams, and receives ion beams of constant, microscale and trace levels; the back-end analysis device is connected with the ion detector, and is used for eliminating a background of an isotope to be measured at an ultratrace level; and the ion detector is used for receiving ion beams of the ultratrace level, and carrying out energy measurement and separation on the ion beams of the ultratrace level, so as to obtain the isotope to be measured at the ultratrace level.

Improvements to a side-on Penning trap include methods to stabilize ions in the trap. The ions are stabilized by injecting ions in the focusing region of the non-uniform DC fields produced by the pad electrodes of the trap. Ions are injected along an injection axis shifted from the central axis of a gap between a positively biased electrode pad and negatively biased electrode pad of the trap. Improvements also include methods to compensate for the Lorentz force that is produced when ions are injected into a side-on Penning trap. Electrodes of an ion injection device are DC biased so that the electrodes produce an electric field along the axis of the device that compensates for the Lorentz force. Finally, methods are provided to increase the m/z range of ions injected into a side-on Penning trap by pre-trapping ions just before injection of the ions into the trap.

Improvements to a side-on Penning trap include methods to stabilize ions in the trap. The ions are stabilized by injecting ions in the focusing region of the non-uniform DC fields produced by the pad electrodes of the trap. Ions are injected along an injection axis shifted from the central axis of a gap between a positively biased electrode pad and negatively biased electrode pad of the trap. Improvements also include methods to compensate for the Lorentz force that is produced when ions are injected into a side-on Penning trap. Electrodes of an ion injection device are DC biased so that the electrodes produce an electric field along the axis of the device that compensates for the Lorentz force. Finally, methods are provided to increase the m/z range of ions injected into a side-on Penning trap by pre-trapping ions just before injection of the ions into the trap.

A method of operating a Fourier Transform (FT) mass analyzer, which has a plurality of selectable resolving power settings, includes storing an optimized voltage value in association with each one of the plurality of selectable resolving power settings. More particularly, the optimized voltage values for at least two of the selectable resolving power settings differ from one another. When a user selects one of the plurality of selectable resolving power settings, the optimized voltage value that is stored in association therewith is retrieved. At least one voltage setting of the FT mass analyzer is controlled, based on the retrieved optimized voltage value, and an analytical scan is performed at the selected one of the plurality of selectable resolving power settings for a population of ions within the FT mass analyzer.

The disclosure relates to an ion guiding device, including two sets of electrodes extending along a certain space axis, a first power supply device and a second power supply device. The electrodes are expandably arranged along a direction perpendicular to the space axis, at least one surface of each electrode in each set of electrodes is substantially on the same space plane, and the space planes for each set of electrodes are not same and not parallel, thereby forming an ion transmission channel having the cross sectional area gradually reduced in a direction perpendicular to the space axis; the first power supply device is used for applying radio-frequency voltages on at least a part of electrodes in the two sets of electrodes; and the second power supply device is used for applying voltage signals on at least a part of electrodes in the two sets of electrodes.

In one aspect, a mass analyzer is disclosed, which comprises a quadrupole having an input end for receiving ions and an output end through which ions can exit the quadrupole, said quadrupole having a plurality of rods to at least some of which a drive RF signal and an excitation signal can be applied. A fixed phase relationship is maintained between the drive RF signal and the excitation signal, thereby enhancing the signal-to-noise ratio of the mass detection signal.

In one aspect, a mass analyzer is disclosed, which comprises a quadrupole having an input end for receiving ions and an output end through which ions can exit the quadrupole, said quadrupole having a plurality of rods to at least some of which a drive RF signal and an excitation signal can be applied. A fixed phase relationship is maintained between the drive RF signal and the excitation signal, thereby enhancing the signal-to-noise ratio of the mass detection signal.

A method of operating a Fourier Transform (FT) mass analyzer, which has a plurality of selectable resolving power settings, includes storing an optimized voltage value in association with each one of the plurality of selectable resolving power settings. More particularly, the optimized voltage values for at least two of the selectable resolving power settings differ from one another. When a user selects one of the plurality of selectable resolving power settings, the optimized voltage value that is stored in association therewith is retrieved. At least one voltage setting of the FT mass analyzer is controlled, based on the retrieved optimized voltage value, and an analytical scan is performed at the selected one of the plurality of selectable resolving power settings for a population of ions within the FT mass analyzer.