Abstract: A method of providing reagent ions to a mass spectrometer comprises delivering a reagent species to a reagent ionization volume via a passageway at a flow rate. Using previously acquired information, an injection time duration is calculated for injecting reagent ions that are formed in the reagent ionization volume into a reaction region of the mass spectrometer. A determination is made as to whether the calculated injection time duration is within a specified range of injection time duration values. When it is determined that the calculated injection time duration falls outside of the specified range of injection time duration values, the flow rate at which the reagent species is delivered to the ionization volume is adjusted.

Abstract: A front-end reagent ion source for a mass spectrometer is disclosed. Reagent vapor is supplied to a reagent ionization volume located within a chamber of the mass spectrometer and maintained at a low vacuum pressure. Reagent ions are formed by interaction of the reagent vapor molecules with an electrical discharge (e.g., a glow discharge) within the ionization volume, and pass into the chamber of the mass spectrometer. At least one ion optical element located along the analyte ion path transports the reagent ions to successive chambers of the mass spectrometer. The reagent ions may be combined with the analyte ions to perform ion-ion studies such as electron transfer dissociation (ETD).

Abstract: Auxiliary electrodes for creating drag fields may be provided as arrays of finger electrodes on thin substrates such as printed circuit board material for insertion between main RF electrodes of a multipole. A progressive range of voltages can be applied along lengths of the auxiliary electrodes by implementing a voltage divider that utilizes static resisters interconnecting individual finger electrodes of the arrays. Dynamic voltage variations may be applied to individual finger electrodes or to groups of the finger electrodes.

Abstract: A front-end reagent ion source for a mass spectrometer is disclosed. Reagent vapor is supplied to a reagent ionization volume located within a chamber of the mass spectrometer and maintained at a low vacuum pressure. Reagent ions are formed by interaction of the reagent vapor molecules with an electrical discharge (e.g., a glow discharge) within the ionization volume, and pass into the chamber of the mass spectrometer. At least one ion optical element located along the analyte ion path transports the reagent ions to successive chambers of the mass spectrometer. The reagent ions may be combined with the analyte ions to perform ion-ion studies such as electron transfer dissociation (ETD).

Abstract: Auxiliary electrodes for creating drag fields may be provided as arrays of finger electrodes on thin substrates such as printed circuit board material for insertion between main RF electrodes of a multipole. A progressive range of voltages can be applied along lengths of the auxiliary electrodes by implementing a voltage divider that utilizes static resisters interconnecting individual finger electrodes of the arrays. Dynamic voltage variations may be applied to individual finger electrodes or to groups of the finger electrodes.

Abstract: A front-end ion source for a mass spectrometer generates both analyte and reagent ions. The reagent source may include a heater for vaporizing a condensed-phase reagent substance and an electron source for ionizing reagent molecules. The interior of the reagent ionization chamber is purged with a purge gas to avoid or minimize reaction of the reagent ions with oxygen or other reactive species, thereby enabling operation of the reagent ionization chamber at or near atmospheric pressure. The reagent and analyte ions are directed into a reduced-pressure chamber through separate passageways. An ion transport optic selectively transmits one of the analyte ions or the reagent ions from the reduced-pressure chamber to downstream regions of the mass spectrometer.

Abstract: A method of controlling the population of ions in a mass spectrometer in which a first sample of ions is provided in the mass spectrometer, a measure of abundance of a species of interest in the first sample of ions is determined, the measure of abundance comprising an intensity value, and a second sample of ions is introduced into the mass spectrometer. The second sample of ions is introduced in an amount determined at least in part on the measure of abundance of the species of interest in the first sample of ions.

Abstract: Disclosed are a time-of-flight mass spectrometer and signal processing electronics. The signal processing electronics include a plurality of time-to-digital converters configured to receive signal pulses from the same detector anode within the time-of-flight mass spectrometer. The signal processing electronics are further configured to differentiate, and compensate for, those signal pulses caused by the detection of more than one ion. Differentiation and compensation are achieved by using the time-to-digital converters to detect the leading and trailing edges of a signal pulse. The time difference between the detection of the leading edge and detection of the trailing edge is indicative of whether or not the signal pulse was generated by the detection of more than one ion.

Abstract: An apparatus that comprises material which have different thermal expansion coefficients, combined in such a way that the length of the drift region is variant, and self adjusting with temperature. The adjustment is such as to compensate for the length changes resulting from thermal expansion or contraction in other ion optical elements, such that ions of substantially equivalent mass to charge ratios maintain a constant flight time though the system. This allows for use of standard construction methods for the ion optical elements.

Abstract: An apparatus that comprises material which have different thermal expansion coefficients, combined in such a way that the length of the drift region is variant, and self adjusting with temperature. The adjustment is such as to compensate for the length changes resulting from thermal expansion or contraction in other ion optical elements, such that ions of substantially equivalent mass to charge ratios maintain a constant flight time though the system. This allows for use of standard construction methods for the ion optical elements.

Abstract: A method of controlling the population of ions in a mass spectrometer in which a first sample of ions is provided in the mass spectrometer, a measure of abundance of a species of interest in the first sample of ions is determined, the measure of abundance comprising an intensity value, and a second sample of ions is introduced into the mass spectrometer. The second sample of ions is introduced in an amount determined at least in part on the measure of abundance of the species of interest in the first sample of ions.