A mass analyzer for scanning sample gases is disclosed. The mass analyzer comprises an ionizer for generating ions from a sample; a mass filter with an accumulator section integrated in the mass filter and accumulates filtered ions prior to ejecting from the mass filter; and an ion detector that is configured to detecting ejected ions from the mass filter. The mass filter may include a quadrupole array and the accumulator section includes an ion trap array.

A multipole assembly configured to be disposed in a mass spectrometer includes a plurality of rod electrodes. Each rod electrode included in the plurality of rod electrodes may be made of molybdenum. The multipole assembly further includes a sacrificial anode in electrical contact with a rod electrode included in the plurality of rod electrodes. The sacrificial anode is made of a material having an electrochemical potential that is more negative than the electrochemical potential of the rod electrode.

A method of operating a mass spectrometer, comprising: generating ions from a sample; mass filtering the ions using a quadrupole mass filter having a set of selection parameters to transmit ions within at least one selected range of mass-to-charge ratios narrower than an initial range, wherein the quadrupole comprises four parallel elongate electrodes arranged in opposing pairs to which are applied RF and DC, wherein an attractive DC voltage is applied to one pair of opposing electrodes and a repulsive DC voltage is applied to the other pair; mass analysing or detecting the ions transmitted by the quadrupole mass filter; repeating the steps of generating ions, mass filtering and mass analysing or detecting multiple times; switching a configuration of the pairs of opposing electrodes to which the attractive DC voltage and the repulsive DC voltage are applied multiple times over the course of repeating the steps so that over long term operation the build-up of contamination on each pair of opposing electrodes is substantially equal; and determining mass filtering steps for which quantitative accuracy should be maintained between them and for the determined mass filtering steps maintaining the same configuration of the pairs of opposing electrodes to which the attractive DC voltage and the repulsive DC voltage are applied. The width of the selected mass range may change by not more than 10% when the ion transmission efficiency mass filter falls by 50% or more due to the build-up of contamination on the electrodes.

An ion optical arrangement (1) for use in a mass spectrometer comprises a collision cell defining an ion optical axis along which ions may pass, electrodes comprising a set of parallel poles (11A, 11B, 11C) arranged in the collision cell, and a voltage source for providing voltages to the electrodes to produce electric fields. The ion optical arrangement is arranged for switching between a first operation mode in which the collision cell is pressurized and a second operation mode in which the collision cell is substantially evacuated. The ion optical arrangement is further arranged for producing a radio frequency electric focusing field in the first operation mode and a static electric focusing field in the second operation mode.

A method of operating a mass spectrometer, comprising: generating ions from a sample; mass filtering the ions using a quadrupole mass filter having a set of selection parameters to transmit ions within at least one selected range of mass-to-charge ratios narrower than an initial range, wherein the quadrupole comprises four parallel elongate electrodes arranged in opposing pairs to which are applied RF and DC, wherein an attractive DC voltage is applied to one pair of opposing electrodes and a repulsive DC voltage is applied to the other pair; mass analysing or detecting the ions transmitted by the quadrupole mass filter; repeating the steps of generating ions, mass filtering and mass analysing or detecting multiple times; switching a configuration of the pairs of opposing electrodes to which the attractive DC voltage and the repulsive DC voltage are applied multiple times over the course of repeating the steps so that over long term operation the build-up of contamination on each pair of opposing electrodes is substantially equal; and determining mass filtering steps for which quantitative accuracy should be maintained between them and for the determined mass filtering steps maintaining the same configuration of the pairs of opposing electrodes to which the attractive DC voltage and the repulsive DC voltage are applied. The width of the selected mass range may change by not more than 10% when the ion transmission efficiency mass filter falls by 50% or more due to the build-up of contamination on the electrodes.

Systems and methods described herein utilize a multipole ion guide that can receive ions from an ion source for transmission to downstream mass analyzers, while preventing unwanted/interfering/contaminating ions from being transmitted into the high-vacuum chambers of mass spectrometer systems. In various aspects, RF and/or DC signals can be provided to auxiliary electrodes interposed within a quadrupole rod set so as to control or manipulate the transmission of ions from the multipole ion guide.

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.

Dynamic skimmer pulsing and dynamic equilibration times are used for MS and MS/MS scans. A target percentage transmission of the ion beam is calculated based on a previous percentage transmission and a previous TIC or a previous highest intensity of a previous cycle time. An equilibration time is calculated based on the current percentage transmission and the target percentage transmission. A skimmer of a tandem mass spectrometer is controlled to attenuate the ion beam to the target percentage transmission to prevent saturation of a detector of the tandem mass spectrometer and to increase the dynamic range of the tandem mass spectrometer. The tandem mass spectrometer is controlled to perform an MS scan or an MS/MS scan after the calculated equilibration time to reduce the cycle time.

According to some aspects, a spectrometer is provided, the spectrometer configured to receive molecules of a plurality of metabolites including one or more molecules of a first metabolite, filter the received molecules to retain molecules of the first metabolite including a plurality of different mass isotopomers of the first metabolite, fragment molecules of a first mass isotopmer of the retained molecules to produce a first plurality of daughter ions, measure abundances of the first plurality of daughter ions as a function of daughter ion mass, fragment molecules of a second istopomer, different from the first mass isotopmer, of the retained molecules to produce a second plurality of daughter ions, and measure abundances of the second plurality of daughter ions as a function of the daughter ion mass.

A mass analyzer for scanning sample gases is disclosed. The mass analyzer comprises an ionizer for generating ions from a sample; a mass filter with an accumulator section integrated in the mass filter and accumulates filtered ions prior to ejecting from the mass filter; and an ion detector that is configured to detecting ejected ions from the mass filter. The mass filter may include a quadrupole array and the accumulator section includes an ion trap array.