Jeol Ltd.

Shimadzu Corporation

Osaka University

Morio Ishihara

Michisato Toyoda

Shinichi Yamaguchi

Takaya Sato

Daisuke Okumura

A method and apparatus for time-of-flight (TOF) mass spectrometry. The apparatus improves the ion focusing properties in an orthogonal direction and permits connection with an orthogonal-acceleration ion source for improvement of sensitivity. The apparatus comprises an ion source for emitting ions in a pulsed manner, an analyzer for realizing a helical trajectory, and a detector for detecting the ions. The analyzer is composed of plural laminated toroidal electric fields to realize the helical trajectory.

Method and apparatus for time-of-flight mass spectrometry

A time of flight type mass spectrometer (TOF-MS) of the present invention includes: a flight space containing a loop orbit on which ions fly once or more than once; a flight controller for making ions of a same mass to charge ratio fly the loop orbit at several values of number of turns; a flight time measurer for measuring a length of flight time of the ions; and a processor for determining the mass to charge ratio of the ions based on a relationship between the value of number of turns and the length of flight time of the ions. The speed of ions flying a loop orbit depends on their mass to charge ratios. For ions of the same mass to charge ratio, the difference between the lengths of flight time of the ions flying the loop orbit N turns and of the ions flying the loop orbit N+1 turns depends on the speed of the ions, so that the difference depends on the mass to charge ratio of the ions. The difference in the length of flight time is unrelated to the variation in the starting time (jitter), variation in the detection timing (jitter), etc, so that the value of the mass to charge ratio can be precisely determined free from errors caused by such disturbing factors.

Time of flight mass spectrometer

In the mass spectrometer of the present invention, a flight space is provided before the mass analyzer, and the flight space includes a loop orbit on which ions fly repeatedly. While ions fly on the loop orbit repeatedly, ion selecting electrodes placed on the loop orbit selects object ions having a specific mass to charge ratio in such a manner that, for a limited time period when the object ions are flying through the ion selecting electrodes, an appropriate voltage is applied to the ion selecting electrodes to make them continue to fly on the loop orbit, but otherwise to make or let other ions deflect from the loop orbit. If ions having various mass to charge ratios are introduced in the loop orbit almost at the same time, the object ions having the same mass to charge ratio continue to fly on the loop orbit in a band, but ions having mass to charge ratios different from that are separated from the object ions while flying on the loop orbit repeatedly. Even if the difference in the mass to charge ratio is small, the separation becomes large when the number of turns of the flight becomes large. After such a separation is adequately achieved, the ion selecting electrodes can select the object ions with high selectivity, or at high mass resolution. By adding dissociating means, fragment ions originated only from the selected object ions can be analyzed, which enables the identification and structural analysis of the sample at high accuracy.

Mass spectrometer

In a time of flight mass spectrometer (TOF-MS) of the present invention, a flight controller makes ions fly a loop orbit a predetermined number of turns, and an ion detector detects the ions at each turn of the flight. A flight time measurer measures the length of flight time of ions of a same mass to charge ratio at every turn, and a data processor constructs a spectrum of flight time. The data processor further computes the Fourier transformation of the spectrum, and determines the mass to charge ratio of the ions based on a frequency peak appearing in the Fourier transformation.

In an analysis using a mass spectrometer having a loop orbit along which ions are made to fly a plurality of times, the present invention provides a method of determining the mass-to-charge ratio of an ion without limiting the range of the mass-to-charge ratio of the ions to be brought into the loop orbit while allowing the lapping of the orbiting ions. The measurement is carried out two or more times under different conditions (Tg=500[&#x3bc;s], 400[&#x3bc;s]) under which the number of turns of the ion concerned is different. Flight times are determined from the flight time spectrums obtained by at least two measurements. Though the numbers of turns themselves are unknown, it is possible to calculate possible mass-to-charge ratios for each flight time by incrementally setting the number of turns at plural values. The two sets of possible mass-to-charge ratios derived from the two flight time values (525[&#x3bc;s], 441[&#x3bc;s]) determined by the two measurements are compared with each other, and a value that is found in both measurement results is selected as the mass-to-charge ratio of the ion concerned. Thus, it is possible to determine the mass-to-charge ratio without limiting the range of the mass-to-charge ratio before the ions are brought into the loop orbit.

Method of determining mass-to-charge ratio of ions and mass spectrometer using the method

A mass spectrometer includes a flight control device for allowing ions from an ion source to repeatedly fly along an orbit in a flight space for predetermined times; a detecting device for detecting the ions after the ions repeatedly fly along the orbit for the predetermined times; and a data processing device for starting collection of ion strength data detected by the detecting device. The ion strength data is obtained during the flight of the ions along the orbit, or when the ions are headed toward the detecting device after departing from the orbit, or when one of the above situations is estimated.

The present invention provides a time of flight mass spectrometer having a spiral flight path, whose mass resolution can be appropriately changed with respect to the analysis object or other factor without any complicated alteration or addition of the mechanical construction. In a specific form of the invention, the mass spectrometer includes deflecting electrodeslocated between semi-cylindrical electrodesandfor making ions fly along a spiral path. The deflecting electrodesgenerate deflecting electric fields for shifting the ions in the axial direction of the semi-cylindrical electrodesand. The voltage applied to the deflecting electrodesis changed according to the mass resolution required. The deflecting electric fields are generated or removed with the change of the voltage, which makes the ions fly either along a spiral path or in the same loop orbit. The flight distance of the ions can be controlled as desired by regulating the voltage so that the ions fly in the loop orbit an appropriate number of times. Thus, the mass resolution can be arbitrarily controlled.

Mass spectrometer and method of determining mass-to-charge ratio of ion

A method of mass analysis using a multi-turn time-of-flight mass spectrometer starts with recording plural heterogeneous turn number spectra F(t), F(t), . . . , F(t) containing plural ion peaks that might be different in number of turns, the spectra being obtained with different ion residence times taken from entry to departure using a multi-correlation function for reconstructing a single turn number spectrum.

Method of multi-turn time-of-flight mass analysis

A small-sized, high-resolution, time-of-flight (TOF) mass spectrometer has a closed ion orbit formed by plural electric sectors. Ions can make plural revolutions in the closed orbit. An entrance path is formed in the closed orbit to introduce ions into the closed orbit. An exit path is formed in the closed orbit to take ions from the closed orbit. The entrance and exit paths can be formed at the exit and entrance of the electric sectors forming the closed orbit or can be positioned in the orbit between the electric sectors forming the closed orbit.

Time-of-flight mass spectrometer

There is disclosed a time-of-flight (TOF) mass spectrometer capable of making a spectral measurement quickly and efficiently and making effective use of ionized samples. The instrument has a pulse-generating portion for producing appropriate pulse sequences. An arithmetic unit Fourier-transforms a resultant spectrum from a detector to find W(.omega.). The arithmetic unit Fourier-transforms a pulse sequence signal from the pulse-generating portion to find H(.omega.). The arithmetic unit calculates Y(.omega.)=W(.omega.)/H(.omega.) and takes the inverse Fourier transform of the calculated Y(.omega.).

Time-of-flight mass spectrometer and mass spectrometric method sing same

There is disclosed a mass spectrometer capable of performing a mass analysis by accelerating ions to high energies. This spectrometer has a drift zone consisting of a conductive tube located in the ion path between the ion source and the analyzer. A voltage is applied to the drift zone from a voltage source via a switch such that the voltage applied to the drift zone is switched between a low potential V and an accelerating voltage Va of several kilovolts.

There is disclosed a method of extracting information about the mass of a substance from a complex mass spectrum containing peaks arising from polyvalent ions. These polyvalent ions possess electric charges which are integral multiples of the elementary electric charge. Ions including these polyvalent ions are detected, and a mass spectrum is obtained. On the mass spectrum, ion intensity I is represented as a function of a variable x corresponding to mass-to-charge ratio. The mass spectrum, given by I(x), is transformed into a mass spectrum I(t) of a variable t, using the relation t=1/(x-H), where H is a unit mass of ions added to the polyvalent ions. Peaks appear on the mass spectrum I(t). Among these peaks, at least a given number of peaks appear at regular intervals. The spacing between these regularly spaced peaks is found.

Method of processing mass spectrum

A magnetic mass spectrometer having a one or two-dimensional ion detector for simultaneously detecting all ions focused and separated by the magnetic field. An electrostatic or magnetic octupole lens producing an octupole field is disposed in the ion path between the magnetic field and the detector.

Growing community of inventors

Osaka-fu, Japan

Morio Ishihara