Abstract: A method of mass spectrometry is disclosed comprising automatically correcting the mass or mass to charge ratio resolution of a quadrupole mass filter or mass analyser one or more times during an experimental run or acquisition based upon a measurement, determination or estimation of the mass or mass to charge ratio resolution of one or more reference ions observed in a mass spectrum or mass spectral data acquired either during the same experimental run or acquisition or during a previous experimental run or acquisition.

Abstract: A mass spectrometer is disclosed comprising two vacuum chambers maintained at different pressures. The two vacuum chambers are interconnected by a differential pumping aperture. The effective area of the opening between the two vacuum chambers may be varied by rotating a disk having an aperture in front of the differential pumping aperture so as to vary the gas flow rate through the opening and between the two chambers.

Abstract: An ion guide or mass analyser is disclosed comprising a plurality of electrodes having apertures through which ions are transmitted in use. A pseudo-potential barrier is created at the exit of the ion guide or mass analyser. The amplitude or depth of the pseudo-potential barrier is inversely proportional to the mass to charge ratio of an ion. One or more transient DC voltages are applied to the electrodes of the ion guide or mass analyser in order to urge ions along the length of the ion guides or mass analyser. The amplitude of the transient DC voltage applied to the electrode may be increased with time so that ions are caused to be emitted from the ion guide or mass analyser in reverse order of their mass to charge ratio.

Abstract: A mass spectrometer or ion mobility spectrometer is disclosed comprising means for detecting a blockage in an inlet orifice arranged between an ion source and a vacuum chamber. The blockage is detected as a result of a reduction in pressure within the vacuum chamber. This change in pressure is detected indirectly by monitoring the amount of power that a vacuum pump is using, the amount of current that a vacuum pump is drawing, the temperature of a vacuum pump or a region in proximity to the vacuum pump, or the flow rate of gas out of a vacuum pump.

Abstract: Apparatus for a mass spectrometer is disclosed comprising an ion source, a heater for heating a gas flow to the ion source, a temperature sensor for monitoring the temperature of the heater, and a control system. The control system is arranged and adapted to determine a flow rate of the gas flow by monitoring the power supplied to the heater and the temperature of the heater.

Abstract: There is provided a mass spectrometer comprising a time of flight mass analyser comprising an acceleration electrode, a time of flight region and an ion detector, and a control system arranged and adapted (i) to apply a plurality of extraction pulses to said acceleration electrode in order to accelerate consecutive groups of ions into said time of flight region, wherein ions having a relatively high mass to charge ratio in a preceding group of ions arrive at said detector after ions having a relatively low mass to charge ratio in a subsequent group of ions, wherein ions within each consecutive group of ions have a mass to charge ratio within one or more predetermined, selected or otherwise known mass to charge ratio ranges, and (ii) to determine a frequency or period of said plurality of extraction pulses that will avoid coincidence of ions from said consecutive groups of ions at said ion detector, wherein said plurality of extraction pulses are applied at said determined frequency or period.

Abstract: A method of constructing an ion guide is disclosed comprising providing an elongated spine member and a plurality of plates. Each plate comprises an aperture therethrough for receiving the spine member and at least one electrode for use in guiding ions. The apertures of the plates are arranged around the spine member and the plates are arranged along the spine member. The plates are then locked in position on the spine member such that the plates are fixed axially with respect to the spine member and so that the electrodes of the plates are arranged so as to form an array of electrodes for use in guiding ions.

Abstract: A miniature mass spectrometer is disclosed comprising an atmospheric pressure ionisation source and a first vacuum chamber having an atmospheric pressure sampling orifice or capillary, a second vacuum chamber located downstream of the first vacuum chamber and a third vacuum chamber located downstream of the second vacuum chamber. An ion detector is located in the third vacuum chamber. A first RF ion guide is located within the first vacuum chamber and a second RF ion guide is located within the second vacuum chamber. The ion path length from the atmospheric pressure sampling orifice or capillary to an ion detecting surface of the ion detector is ?400 mm. The mass spectrometer further comprises a tandem quadrupole mass analyser, a 3D ion trap mass analyser, a 2D or linear ion trap mass analyser, a Time of Flight mass analyser, a quadrupole-Time of Flight mass analyser or an electrostatic mass analyser arranged in the third vacuum chamber.

Abstract: A method of Electrospray ionization is disclosed comprising passing a sample liquid through a liquid chromatography column, monitoring a liquid chromatography back pressure and varying a voltage applied to an Electrospray ionization source electrode in dependence upon said monitored liquid chromatography back pressure.

Abstract: A mass or mass to charge ratio selective ion trap is disclosed which directs ions into a small ejection region. A RF voltage acts to confine ions in a first (y) direction within the ion trap. A DC or RF voltage acts to confine ions in a second (x) direction. A quadratic DC potential well acts to confine ions in a third (z) direction within the ion trap. The profile of the quadratic DC potential well progressively varies along the second (x) direction.

Abstract: A method of mass spectrometry is disclosed comprising directing first photons from a laser onto ions located within a 2D or linear ion guide or ion trap. The frequency of the first photons is scanned and first photons and/or second photons emitted by the ions are detected. The ions are then mass analysed using a Time of Flight mass analyser.

Abstract: A method of mass spectrometry or ion mobility spectrometry is disclosed comprising: providing gas phase analyte in a vacuum housing; electrospraying a reagent solution outside of the vacuum housing so as to form charged droplets of reagent solution and/or reagent ions; conveying the charged droplets and/or reagent ions into the vacuum housing and reacting them with the analyte so as to form analyte ions; and analysing the analyte ions with a mass analyser and/or ion mobility analyser. Reacting the droplets of reagent solution and/or reagent ions with the analyte in sub-atmospheric pressures improved the reaction conditions.

Abstract: A method of detecting and sequencing post translationally modified peptides is disclosed wherein a negative ion precursor scan is performed. A negative ion high resolution MS scan is then performed and then MRM channels in positive ion mode are determined and monitored. A positive ion MS/MS scan is then performed.

Abstract: A method of mass spectrometry is disclosed comprising passing ions through a first stage and a second stage of a mass spectrometer and monitoring a first ion acquisition for a first dwell time extending from a time T1 to a time T1+Tdwell1. The method further comprises reconfiguring the mass spectrometer or one or more components of the mass spectrometer to monitor a second ion acquisition and setting the first stage to transmit ions of the second ion acquisition at a time T, wherein T<T1+Tdwell1.

Abstract: A mass spectrometer is disclosed comprising a first mass filter comprising a plurality of electrodes and a first device arranged and adapted to generate an axial force which drives at least some ions axially through or along the first mass filter and a quadrupole mass filter or mass analyser arranged downstream of the mass filter.

Abstract: A method of constructing an ion guide is disclosed comprising providing an elongated spine member and a plurality of plates. Each plate comprises an aperture therethrough for receiving the spine member and at least one electrode for use in guiding ions. The apertures of the plates are arranged around the spine member and the plates are arranged along the spine member. The plates are then locked in position on the spine member such that the plates are fixed axially with respect to the spine member and so that the electrodes of the plates are arranged so as to form an array of electrodes for use in guiding ions.

Abstract: A miniature mass spectrometer is disclosed comprising an atmospheric pressure ionisation source and a first vacuum chamber having an atmospheric pressure sampling orifice or capillary, a second vacuum chamber located downstream of the first vacuum chamber and a third vacuum chamber located downstream of the second vacuum chamber. An ion detector is located in the third vacuum chamber. A first RF ion guide is located within the first vacuum chamber and a second RF ion guide is located within the second vacuum chamber. The ion path length from the atmospheric pressure sampling orifice or capillary to an ion detecting surface of the ion detector is ?400 mm. The mass spectrometer further comprises a tandem quadrupole mass analyser, a 3D ion trap mass analyser, a 2D or linear ion trap mass analyser, a Time of Flight mass analyser, a quadrupole-Time of Flight mass analyser or an electrostatic mass analyser arranged in the third vacuum chamber.

Abstract: A method of mass spectrometry is disclosed comprising directing first photons from a laser onto ions located within a 2D or linear ion guide or ion trap. The frequency of the first photons is scanned and first photons and/or second photons emitted by the ions are detected. The ions are then mass analyzed using a Time of Flight mass analyzer.

Abstract: A method of automatically performing a routine to check the operational state of a mass spectrometer is disclosed wherein the method is performed automatically as a start-up routine upon switching ON the mass spectrometer. The method comprises automatically generating a vacuum within one or more vacuum chambers of a mass spectrometer and automatically generating first ions using an internal ion source, wherein the internal ion source is located within a vacuum chamber of the mass spectrometer or is located within a chamber downstream from an atmospheric pressure interface, and detecting at least some of the first ions or second ions derived from the first ions. The method further comprises automatically determining whether or not the mass spectrometer is in a correct operational state.

Abstract: A method of fragmenting ions is disclosed comprising providing a linear ion trap comprising: (i) a first electrode set comprising a plurality of first electrodes; (ii) a second electrode set arranged downstream of the first electrode set and comprising a plurality of second electrodes; and (iii) a third electrode set arranged downstream of the second electrode set and comprising a plurality of third electrodes. Ions are axially confined within the linear ion trap. Either: (i) a potential difference between at least some of the first electrodes and at least some of the second electrodes; and/or (ii) a potential difference between at least some of the second electrodes and at least some of the third electrodes, is varied in order to accelerate at least some ions confined within the linear ion trap in order to cause the ions to fragment so as to form fragment or daughter ions.