A high-voltage power source for applying high voltage to a nozzle of an ESI ion source includes a charge release assistant section (26) including switch circuits (62 and 65) and other elements for forcing electric charges accumulated at output terminals to be discharged in a polarity-switching operation, whereby the positive/negative switching of the polarity of the output voltage can be quickly performed. In the mass spectrometer according to the present invention, for example, when the voltage applied to the nozzle needs to be changed from Vi to V.sub.2 (where V.sub.1 and V.sub.2 are positive, and V.sub.1>V.sub.2), a voltage control section (20) under the command of a main controller (9) operates a positive voltage generation section (21) and negative voltage generation section (23) so as to temporarily provide a negative output voltage. After a predetermined period of time, the voltage control section operates the positive voltage generation section (21) and negative voltage generation section (23) so as to provide voltage V.sub.2. If the voltage was simply changed from V.sub.1 to V.sub.2, the voltage would decrease slowly and require considerable time for the change. The positive/negative switching of the polarity induces the discharging of the electric charges accumulated at the output terminals, and consequently, the voltage-switching operation from V.sub.1 to V.sub.2 is quickly performed.

A mass spectrometer is disclosed wherein highly charged fragment ions resulting from Electron Transfer Dissociation fragmentation of parent ions are reduced in charge state within a Proton Transfer Reaction cell by reacting the fragment ions with a neutral superbase reagent gas such as Octahydropyrimidolazepine.

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).

A dual-mode ion detector for a mass and/or ion mobility spectrometer comprising a first conversion electrode (20) that is maintained, in use, at a negative potential and arranged for converting incident positive ions (32) into secondary electrons (34), and a second conversion electrode (22) that is maintained, in use, at a positive potential and arranged for converting incident negative ions (42) into secondary positive ions (44) and/or secondary electrons (74). The detector also comprises an electron detecting surface (26) and an entrance electrode (24) for drawing ions into the ion detector. The ion detector is switchable between a first mode for detecting positive ions and a second mode for detecting negative ions.

The present invention implements an ion detector with which it is possible to avoid direct collisions of negative ions with a scintillator, prevent degradation of the scintillator, prolong life of the scintillator, reduce the need for maintenance, and perform highly sensitive detection of both positive and negative ions. With respect to a reference line 65 connecting a central point 63 of a positive ion CD 52 and a central point 64 of a counter electrode 54, a central point 66 of a negative ion CD 53 is provided in a region of a side opposite to a region of a side of a central point 67 of a scintillator 56. Positive ions entering from an ion entrance 62 receive a deflection force and collide with the positive ion CD 52 to generate secondary electrons. The generated secondary electrons collide with the scintillator 56 to generate light. The generated light passes through a light guide 59 and is detected by a photomultiplier tube 58. A negative potential barrier is generated along the reference line 65. Negative ions entering form the ion entrance 62 are attracted to and collide with the negative ion CD 53 to generate positive ions. The generated positive ions collide with the positive ion CD 52 to generate secondary electrons. The generated secondary electrons collide with the scintillator 56 and are detected by the photomultiplier tube 58.

The invention relates to a method for mass analysing positively charged ions and negatively charged ions with a mass analyser arrangement (10). The method includes inserting the positively charged ions and the negatively charged ions via an intake (13) of the mass analyser arrangement (10) into a mass analysis chamber (14) of the mass analyser arrangement (10). Furthermore, the method includes transferring inside the mass analysis chamber (14) the positively charged ions from the intake (13) to a first mass analyser (11) of the mass analyser arrangement (10) and mass analysing the positively charged ions with the first mass analyser (11) and transferring inside the mass analysis chamber (14) the negatively charged ions from the intake (13) to a second mass analyser (12) of the mass analyser arrangement (10) and mass analysing the negatively charged ions with the second mass analyser (12). The invention furthermore relates to the mass analyser arrangement (10) for mass analysing positively charged ions and negatively charged ions with the method according to the invention.

A method of ion detection comprises: (a) setting electrical potentials of a dynode and a scintillator electrode of a Daly detector and of a focusing lens disposed at an ion inlet of the Daly detector so as to detect negatively charged ions received from a mass analyzer or mass filter; (b) transferring the negatively charged ions from the mass analyzer or mass filter to the Daly detector through the lens and detecting said negatively charged ions by a photodetector of the Daly detector; (c) setting electrical potentials of the dynode, the scintillator electrode and the focusing lens of the Daly detector so as to detect positively charged ions received from the mass analyzer or mass filter; and (d) transferring the positively charged ions from the mass analyzer or mass filter to the Daly detector through the lens and detecting said positively charged ions by the photodetector.

A method identifies the molecular structure of each component in a multicomponent mixture. The method includes (1) subjecting the multicomponent mixture to mass spectrometry to identify the formula of a molecule attributed to each obtained peak, and to identify abundance of the molecule; (2) subjecting the multicomponent mixture to collision induced dissociation; (3) performing mass spectrometry on each fragment ion generated via the collision induced dissociation in (2) to identify the core structure forming each fragment ion and abundance thereof; (4) dividing the molecules attributed to each peak in (1) into “classes” based on “a type and number of heteroatoms, and a DBE value”, and on all the molecules belonging to each “class”, estimating the existence state and abundance thereof; and (5) determining the core structure forming each molecule, for which the existence state is estimated in (4), and determining and assigning a side chain and a cross-link thereto.

An ion detector that can detect either positive or negative ions comprises: an ion inlet comprising an ion focusing lens; a dynode having a surface configured to intercept, within a zone of interception, a stream of ions passing through the ion focusing lens, wherein a plane that is tangent to the dynode surface at the zone of interception is disposed at an angle to a line that passes through the center of the dynode surface and the center of the focusing lens; a scintillator having a surface that is configured to receive secondary electrons emitted from the zone of interception; a scintillator electrode affixed to the scintillator surface; a photodetector configured to receive photons emitted by the scintillator and to generate an electric signal in response thereto; and one or more power supplies electrically coupled to the focusing lens, the dynode, the scintillator electrode and the photodetector.

The present application relates to an ion transmission device, more particularly, to a device and method for generating, storing and transmitting positive and negative ions. The device includes a wire electrode, a perforated insulating board, a tensioning device, an axial field electrode and an ion source for providing ions. The generated positive and negative ions are respectively stored on two ends of a cavity by the device; and the positive or negative ions are led out as needed. The utilization efficiency of positive and negative ions, as well as sensitivity, are greatly improved by the device.