A mass spectrometer includes an ion source configured to ionize a sample to produce ions; a mass analyzer configured to separate the ions based on their mass-to-charge ratio; a detector configured to detect ions; an ion optics component configured to direct ions along at least part of the path from the ion source to the mass analyzer to the detector; and a controller. The controller is configured to switch the source at a first time from a first polarity source voltage to a second polarity source voltage; and switch the detector or the ion optics component at a second time from a first voltage to a second voltage, the second time being offset from the first time, the first voltage being the first polarity detector voltage or the first polarity ion optics voltage and the second voltage being the second polarity detector voltage or the second polarity ion optics voltage.

A method for determining in a sample, by mass spectrometry, the amount of one or more analytes selected from the group consisting of 12,13-DiHOME, 3-hydroxybutyrate (BHBA), 3-hydroxyoctanoate, 3-methylglutarylcarnitine, 3-ureidopropionate, 7-alpha-hydroxy-4-cholesten-3-one (7-Hoca), citrate, fucose, fumarate, gamma-tocopherol, glutamate, glutarate, glycerol, glycochenodeoxycholate, glycocholate, hypoxanthine, maleate, malonate, mannose, orotate, 2,3-pyrdinedicarboxylate, ribose, serine, taurine, taurochenodeoxycholate, taurocholate, palmitoleate, linolenate, xanthine, xylitol, and combinations thereof is described. The method comprises subjecting the sample to an ionization source under conditions suitable to produce one or more ions detectable by mass spectrometry from each of the one or more analytes; measuring, by mass spectrometry, the amount of the one or more ions from each of the one or more analytes; and using the measured amount to determine the amount of each of the one or more analytes in the sample.

The invention relates to a device and a corresponding method for mass spectroscopic analysis of particles, the device comprising: a first irradiation unit (4) configured to irradiate a particle (1) with electromagnetic radiation to cause components of the particle (1) to detach, in particular to desorb, ablate and/or evaporate, from the particle (1), the detached components (2) of the particle (1) being located in proximity of a residual core (3) of the particle (1), a second irradiation unit (14-16, 19) configured to irradiate substantially simultaneously i) at least a part of the detached components (2), and optionally the residual core (3) of the particle (1), with a first beam (17) of electromagnetic radiation to cause an ionization of at least a part of the detached components (2), the first beam (17) of electromagnetic radiation exhibiting a first intensity, and ii) at least a part of the residual core (3) of the particle (1) with a second beam (18) of electromagnetic radiation to cause an ionization of at least a part of the components of the residual core (3) of the particle (1), the second beam (18) of electromagnetic radiation exhibiting a second intensity, which is preferably larger than the first intensity, and a mass spectrometer comprising an ion source region (5) configured to accommodate positive ions (+) and/or negative ions (−) of the detached components (2) and/or of the components of the residual core (3), a first detection channel (6) configured to detect the positive ions (+), and optionally a second detection channel (9) configured to detect the negative ions (−).

In a tandem mass spectrometer, when the measurement mode is switched between a positive ion measurement mode and a negative ion measurement mode, a DC offset voltage applied to a lens electrode to impart collision energy to an ion is temporarily switched to 0V (S1). After being maintained at 0V for a predetermined waiting time (S2), the voltage is changed to a DC offset voltage corresponding to a measurement mode which is used after the switching operation (S3). By such an operation, the voltage difference between the neighboring plate electrodes among the plate electrodes (171, 172, 173) included in the lens electrode can be decreased as compared to the case where the polarity of the DC offset voltage is immediately switched. Consequently, unintended electric discharge between the neighboring electrodes can be prevented.

A metal-channel conversion dynode comprises: a wafer comprising a first face and a second face parallel to the first face and having a thickness less than 1000 m; and a plurality of channels passing through the wafer from the first face to the second face at an angle to a plane of the first face and a plane of the second face. In some embodiments, each inter-channel distance may be substantially the same as the wafer thickness. In some embodiments, the wafer is fabricated from tungsten. In some other embodiments, the wafer comprises a non-electrically conductive material that is fabricated by three-dimensional (3D) printing or other means and that is coated, on its faces and within its channels, with a metal or suitably conductive coating that produces secondary electrons upon impact by either positive or negative ions.

In a tandem mass spectrometer, when the measurement mode is switched between a positive ion measurement mode and a negative ion measurement mode, a DC offset voltage applied to a lens electrode to impart collision energy to an ion is temporarily switched to 0 V (S1). After being maintained at 0 V for a predetermined waiting time (S2), the voltage is changed to a DC offset voltage corresponding to a measurement mode which is used after the switching operation (S3). By such an operation, the voltage difference between the neighboring plate electrodes among the plate electrodes (171, 172, 173) included in the lens electrode can be decreased as compared to the case where the polarity of the DC offset voltage is immediately switched. Consequently, unintended electric discharge between the neighboring electrodes can be prevented.

A method of injecting analyte ions into a mass analyser comprises: injecting analyte ions of a first charge and counter ions of a second charge into an ion trap; cooling the analyte ions and the counter ions simultaneously in the ion trap such that a spatial distribution of the analyte ions therein is reduced; and injecting the analyte ions as an ion packet from the ion trap into the mass analyser. A mass spectrometer controller is configured to: cause an ion source to inject an amount of analyte ions of a first charge and an amount of counter ions of a second charge into an ion trap; cause the ion trap to simultaneously cool the analyte ions and the counter ions in the ion trap, thereby reducing a spatial distribution of the analyte ions therein; and cause the ion trap to inject the analyte ions into a mass analyser.

The present invention relates to a mass spectrometric method for determining (predicting) the presence or absence of a chemical element in an analyte which provides valuable information towards reduction of complexity for annotating a chemical formula to the analyte. The method is based on representing a measured isotopic pattern of an analyte as a feature vector and assigning the feature vector to the presence/absence class using a machine learning algorithm, like a support vector machine (SVM) or an artificial neural network (NN).

Among other things, we describe methods and apparatus for the ionization of target molecular analytes of interest, e.g., for use in mass spectrometry. In some implementations, a thin molecular stream is emitted in either single or a split mode and encounters both an electron-impact ion source and trochoidal electron monochromator placed sequentially or coincidentally. The first ion source emits high-energy electrons (70 eV) to generate characteristic positively-charged mass fragment spectra while the second source emits low-energy electrons in a narrow bandwidth to generate negative molecular ions or other ions via electron capture ionization. The dual ion source may be coupled to analytical instruments such as a gas chromatograph and to any number of mass analyzers such as a polarity switching quadrupole mass analyzer or to multiple mass analyzers.

An apparatus includes a first pair of opposing electrode arrangements that confine ions between them in a portion of a confinement volume inwardly laterally in a first confinement direction with respect to a longitudinal ion propagation direction, each opposing electrode arrangement including an arrangement of RF electrodes situated to receive an unbiased RF voltage having an alternate phase between adjacent RF electrodes of the arrangement of RF electrodes so as to provide the confining of ions between the first pair of opposing electrode arrangements, and a second pair of opposing electrode arrangements that confine the ions between the second pair in the confinement volume inwardly laterally in a second confinement direction that complements the first confinement direction, each opposing electrode arrangement of the second pair including an arrangement of RF electrodes that receive an unbiased RF voltage having an alternate phase between adjacent RF electrodes.