Shimadzu Corporation

Osaka University

Public University Corporation Yokohama City University

Daisuke Okumura

Hiroto Itoi

Kazuo Mukaibatake

Shinichi Yamaguchi

Masaru Nishiguchi

Morio Ishihara

Michisato Toyoda

Tomoya Kudo

Tomoyuki Oshiro

Osamu Furuhashi

Manabu Ueda

Kazuma Maeda

Yoshihiro Ueno

Hiroaki Kozawa

Junichi Taniguchi

Shinjiro Fujita

Hiroshi Sugawara

Yusuke Sakagoshi

Yuta Miyazaki

Shingo Fujioka

Kanako Sekimoto

Mitsuo Takayama

Takuya Suzumura

An orthogonal acceleration time-of-flight mass spectrometer () includes: an ion ejector () which ejects measurement-target ions in a predetermined direction; an orthogonal accelerator () which accelerates ions in a direction orthogonal to the direction in which the ions are ejected; a ring electrode () located between the ion ejector and the orthogonal accelerator, the ring electrode having an opening for allowing ions to pass through and arranged so that the central axis (C2) of the opening is shifted from the central axis (C1) of the ion ejector in a direction along the axis of the acceleration of the ions by the orthogonal accelerator; a reflectron electrode () which creates a repelling electric field for reversing the direction of the ions accelerated by the orthogonal accelerator; and an ion detector () which detects ions after the direction of flight of the ions is reversed by the reflectron electrode.

Orthogonal acceleration time-of-flight mass spectrometer

The other end of an individual sample supply channel one end of which is connected to a gas buffer container the inside of which is empty is connected to one sub-port of a valve that selects one of standard samples to be supplied to an ESI probe. During analysis, the standard sample stored in one of liquid sample containers is selected by switching a connection state of the valve. The standard sample supplied by being pushed by a gas sent to the liquid sample containers through liquid supply gas branch channels is sent to the ESI probe through a sample supply main channel. At the time of finishing analysis, when the valve is switched such that the sub-port and a main port are communicatively connected, a nitrogen gas is sent to the sample supply main channel, and the remaining liquid is discharged.

Liquid sample introduction method and liquid sample introduction device

When a Q-TOF type mass spectrometer is operated in an MSmode, a controller (), at the time of measurement, controls voltage generators (to) such that only a V voltage (radio-frequency voltage for mass separation) and a direct-current bias voltage are applied to main rod electrodes of a quadrupole mass filter () without application of a U voltage (direct-current voltage for mass separation). During a measurement preparation period between a plurality of measurements to obtain one mass spectrum, the controller () controls a U voltage generator () so as to apply the U voltage to the main rod electrodes of the quadrupole mass filter (). Accordingly, a direct-current electric field is formed between adjacent main rod electrodes around an ion optical axis (C) due to a potential difference, and electric charges accumulated in rod holders () holding the main rod electrodes are rapidly removed by an effect of this electric field. As a result, it is possible to eliminate a charge-up that has not been eliminated by a conventional method in which a polarity of a direct-current bias voltage applied to the rod electrodes is merely reversed.

Mass spectrometer

For an automatic adjustment of a detector voltage, a measurement of a standard sample is performed, in which a reflection voltage generator under the control of an autotuning controller applies, to a reflector, voltages which are different from those applied in a normal measurement and do not cause temporal conversion of ions. Ions having the same m/z simultaneously ejected from an ejector are dispersed in the temporal direction and reach a detector. Therefore, a plurality of low peaks corresponding to individual ions are observed on a profile spectrum. A peak-value data acquirer determines a wave-height value of each peak. A wave-height-value list creator creates a list of wave-height values. A detector voltage determiner searches for a detector voltage at which the median of the wave-height values in the wave-height-value list falls within a reference range.

Time-of-flight mass spectrometer

A transfer electrode unit () is configured by coaxially arranging a plurality of loop electrodes (A,B,C), and guides ions to an orthogonal acceleration region (C) by allowing the ions to pass through an inner side of the plurality of electrodes (A,B,C) each of which is applied with a voltage. A voltage having a higher absolute value than the voltage applied to the plurality of electrodes (A,B,C) is applied to a flight tube (), and the ions accelerated in the orthogonal acceleration region (C) are introduced to a flight space formed in the flight tube (). A shield portion (F) is provided between the transfer electrode unit () and the flight tube (), and suppresses that an electric field derived from the voltage applied to the flight tube () enters the transfer electrode unit ().

Even if vibration is applied to an electrode, a connector section is not separated due to urge of a spring section by using a mass spectrometer that includes an electrode (plate-like electrode); a power source section that supplies electric power to the electrode with a predetermined voltage and/or current; a connection line formed of a conductive wire rod having elasticity for electrically connecting the electrode and the power source section; a connector section provided at one end of the connection line; a seat provided in the electrode to be contacted with the connector section; a fixation section provided in the connection line to be fixed to the power source section; and a spring section formed between the connector section and the fixation section of the connection line or in the connector section and for urging the connector section to the seat.

Power connector for mass spectrometer

A multipole ion guide () including a plurality of rod electrodes arranged at an angle to the central axis (C) is placed within a collision cell () located in the previous stage of an orthogonal accelerator (). Radio-frequency voltages with opposite phases are applied to the rod electrodes of the ion guide () so that any two rod electrodes neighboring each other in the circumferential direction have opposite phases of the voltage. A depth gradient of the pseudopotential is thereby formed from the entrance end toward the exit end within the space surrounded by the rod electrodes, and ions are accelerated by this gradient. During an ion-accumulating process, a direct voltage having the same polarity as the ions is applied to the exit lens electrode () to form a potential barrier for accumulating ions. Among the ions repelled by the potential barrier, ions having smaller m/z return closer to the entrance end. Therefore, when the potential barrier is removed and ions are discharged, ions having smaller m/z are discharged at later points in time than those having larger m/z. Therefore, a wide m/z range of ions can be simultaneously accelerated and ejected by an orthogonal accelerator ().

Orthogonal acceleration time-of-flight mass spectrometry

When a normal mass spectrometry is performed without dissociating an ion, the m/z range limitation voltage setting unit applies a radio-frequency voltage to each rod electrode of the quadrupole mass filter and controls the quadrupole voltage generator so as to apply a direct current voltage smaller than that at the time of ion selection for MS/MS spectrometry. When a small direct current voltage is applied, a mass scanning line is set so as to pass through a stability region on a Mathieu diagram over a long range, hence large m/z ions that do not fall within the stability region are blocked in the quadrupole mass filter. By adjusting a cut-off point on larger m/z side blocked in accordance with the measurement period of OA-TOFMS including the orthogonal accelerator, heavy ions that cause period delay are prevented from being introduced into the orthogonal accelerator.

A voltage applied to an exit gate electrode forming a potential barrier and temporarily trapping ions within the inner space of the ion guide is higher than a voltage at an ion guide's exit end. A higher voltage is applied to the exit gate electrode for a lower m/z value of the measurement target ion, to push back the ion which has slowly moved along a potential gradient and reached the exit end of the ion guide. An ion having a lower m/z value is more likely to be located in a farther region from the exit end and forced to travel a longer distance when voltage applied to the exit gate electrode is lowered. A lower m/z value also means a higher travelling speed toward the orthogonal accelerator, whereby m/z dependency of the time required for travel from the ion guide to the orthogonal accelerator eventually becomes low.

A liquid sample introduction system for an ion source which ionizes a liquid sample by supplying the liquid sample to an ionization probein an ion source and making an atomization-promoting gas blow at the liquid sample exiting from the tip of the ionization probe, the liquid sample introduction system including: a liquid sample container-which is a hermetically closable container for holding a liquid sample; a liquid-supply-gas passagehaving one end connected to a point in a passagefor supplying an atomization-promoting gas to the ion source, and the other end connected to a space above a liquid level in the liquid sample container-and a sample supply passagehaving one end connected to a space below the liquid level in the liquid sample container-and the other end connected to the ionization probe

Liquid sample introduction system for ion source

A mass spectrometer includes a collision cell () converging electrode (), accelerating electrode () and front-side ion lens system () which is an electrostatic lens, which are all located within a medium-vacuum region, and a partition wall () for separating the medium-vacuum region from a high-vacuum region and an ion transport optical system () located within the high-vacuum region. Ions which have been extracted and accelerated by an accelerating electric field created between an exit electrode () and the accelerating electrode () are focused into a micro-sized ion-passage opening () by the converging electrode (). The accelerating electrode () blocks a stream of gas, thereby decreasing the chance of contact of ions with gas particles behind the electrode. Additionally, the accelerating electric field imparts a considerable amount of kinetic energy to the ions, thereby preventing the ions from being dispersed even when they come in contact with the gas particles.

An ion transport optical system is disposed between a collision cell and an orthogonal acceleration unit. When releasing ions that are held in the collision cell, an accelerating electric field in which a large potential difference exists is created between an exit-side end of an ion guide and a first stage of the ion transport optical system, and a decelerating electric field in which a relatively small potential difference exists is created between a final stage of the ion transport optical system and an entrance end of the orthogonal acceleration unit. In the accelerating electric field, the velocity of ions is increased overall by imparting a large amount of energy to the ions, and spreading of ions in the ion travel direction that is caused by differences between the mass-to-charge ratios of the ions is reduced.

Ions ejected substantially simultaneously from a collision cell after being temporarily held inside the collision cell arrive at an orthogonal acceleration unit through an ion transport optical system. When the ions enter the orthogonal acceleration unit, voltages having a predetermined potential difference are applied to an entrance-side electrode and an exit-side auxiliary electrode, and as a result an electric field having a rising potential gradient along an axis is created in the orthogonal acceleration unit. As ions having low an m/z values and entering the orthogonal acceleration unit first is significantly decelerate, the packet of ions spread in the X-axis direction in accordance with the m/z values are compressed in the X-axis direction after entering the orthogonal acceleration unit. Thus, a mass-to-charge ratio range of ions that are accelerated in the orthogonal acceleration unit is broadened, and a mass spectrum of a broad range of mass-to-charge ratios can be obtained.

In the ionizer of the present invention, a stream of gas spouted from a nozzle () of a DART ionization unit () vaporizes and ionizes the components in a sample (). Gaseous sample-component molecules which have not been ionized by that process are subsequently ionized by a reaction with a reactant ion produced by a corona discharge generated from a needle electrode (). Such a two-stage ionization of the sample-component molecules improves the ionization efficiency. A needle-electrode support mechanism () adjusts the position and/or angle of the needle electrode () and thereby controls a potential gradient. Therefore, a specific sample-derived ion species can be efficiently introduced into an ion introduction tube () and be detected with a high level of sensitivity.

Ionizer and mass spectrometer including first section for ionizing sample under atmospheric pressure while vaporizing or desorbing the sample component and second section for generating corona discharge

Growing community of inventors

Kyoto, Japan

Daisuke Okumura