Shimadzu Corporation

Hiroto Itoi

Daisuke Okumura

Masaru Nishiguchi

Yoshihiro Ueno

Manabu Shimomura

Kazuo Mukaibatake

Junichi Taniguchi

Shinjiro Fujita

Takeshi Uchida

Kenichi Taniguchi

Provided is an ionization method for ionizing a sampleadhered to a tip of a probethat is electrically conductive, by applying an ionization voltage to the probeto electrically charge the sample. The ionization method includes: subjecting the probeto treatment to make a surface of the probehomogenous; causing adhesion of the sampleto the tip of the probe; and ionizing the sampleby applying the ionization voltage to the probeto electrically charge the sample. The treatment for making the surface of the probehomogenous can be implemented by, for example, causing corona discharge at the probe

Ionization method, ionization device, imaging spectrometry method, and imaging spectrometer

A method of operating an electrode changeover switch which switches the connection state of electrodes, the electrode changeover switch is provided in the wiring path between eight electrodes through, arranged rotation-symmetrically about ion optical axis, and voltage generation switch which generates square wave high voltage &#xb1;V. When switch is switched as shown in the drawing, two circumferentially adjacent rod electrodes are connected to form one set, a square wave voltage of opposite phase is applied to circumferentially adjacent sets, and an effectively quadrupole electric field is formed. When switch is switched, a square wave voltage of opposite phase is applied to circumferentially adjacent rod electrodes and an octupole electric field is formed. In this way, by switching the switch according to the mass range, etc., it becomes possible to rapidly switch the number of poles of a multipole electric field and to suitably transport ions.

Mass spectrometer and method of driving ion guide

In eight electrodes arranged at an interval of a rotational angle of 45&#xb0; around an ion optical axis, two neighboring electrodes are electrically connected together as one group, and electrodes in alternate groups are also electrically connected together. A voltage V+v cos &#x3c9;t is applied to electrodes in alternate groups around the optical axis, and a voltage V&#x2212;v cos &#x3c9;t is applied to the other electrodes. Then, while an ion guide has the same electrode structure as that of an octupole-type ion guide, a radio-frequency electric field mainly having a quadrupole field component is formed, and the ion guide can be used as a quadrupole-type ion guide. Accordingly, only by changing the wiring for applying a voltage by using the electrodes having the same structure, ion guides of, for example, a quadrupole type and an octupole type, having different properties such as ion receiving properties and ion passing properties can be achieved.

Mass spectrograph apparatus and method of driving ion guide

The gas conductance on the ion injection side of a collision cell is made larger than the gas conductance on the ion exit side by providing two ion injection aperturesin the collision cell. Due to the different gas conductances, a CID gas supplied through the gas supply tubegenerally flows in a direction from the ion injection side to the ion exit side in the collision cell, namely, in the ion's passage direction. When the ions injected in the collision cellslow down upon contacting with the CID gas, their progress is assisted by the gas flow, so that the delay of the ions in the collision cellis alleviated. As a result, it is possible to avoid a deterioration in the detection sensitivity of a target product ion and to prevent a ghost peak caused by the stay of the ions.

MS/MS mass spectrometer

A radio-frequency ion guide () for converging ions by a radio-frequency electric field and simultaneously transporting the ions into the subsequent stage is composed of eight rod electrodes (through) arranged in such a manner as to surround an ion optical axis (C). Each of the rod electrodes (through) is disposed at a tilt with respect to the ion optical axis (C) so that the radius rof the inscribed circle () at the end face of the ion exit side is larger than the radius rof the inscribed circle () at the end face of the ion injection side. Accordingly, the gradient of the magnitude or depth of the pseudopotential is formed in the ion's traveling direction in the space surrounded by the rod electrodes (through). Ions are accelerated in accordance with this gradient. Therefore, even in the case where the gas pressure is relatively high and ions have many chances to collide with gas, it is possible to moderate the ions' slowdown and prevent the ions' delay and stop.

Mass spectrometer

During a halt period of time when the introduction of ions is temporarily discontinued to change an objective ion to be selected by a first mass separator in the previous stage, a pulsed voltage having a polarity opposite to that of the ions remaining in a collision cell () is applied to an entrance lens electrode () and exit lens electrode (). The ions are pulled by the DC electric field created by this voltage, to be neutralized and removed by colliding with the lens electrodes (). Thus, the residual ions, which may cause a crosstalk, can be quickly removed from the inner space of the collision cell () without contaminating an ion guide () to which a radio-frequency is applied. Since no radio-frequency voltage is applied to the lens electrodes (), the circuit for applying the pulsed voltage can have a simple configuration. Thus, the cost increase is suppressed.

An electrode member () having two electrode plain plate portions () and one circular portion () is created from a single metal plate, where the two electrode plain plate portions () belong to every other virtual rod electrode around the ion optical axis and face across the ion optical axis, and the circular portion () electrically connects these two electrode plain plate portions (). A predetermined number of resin electric holders () each holding the electrode member () are stacked in the ion optical axis direction, with every other electric member rotated by 90&#xb0; around the ion optical axis, to form a virtual quadrupole rod type ion guide. Since this configuration reduces the number of components more than ever before and saves a cable for connecting electrode plain plate portions () to which the same voltage should be applied, it is possible to reduce the cost and facilitate assembly and regulation in manufacturing and use.

The length of the collision cell () in the direction along the ion optical axis (C) is set to be within the range between 40 and 80 mm, and typically 51 mm, which is remarkably shorter than before. The CID gas is supplied so that it flows in the direction opposite to the ion's traveling direction. Since the energy that an ion receives in colliding with a CID gas increases, it is possible to practically and sufficiently ensure the CID efficiency even though the collision cell () is short. In addition, since the passage distance for an ion is short, the passage time is shortened. Accordingly, it is possible to avoid the degradation in the detection sensitivity and the generation of a ghost peak due to the delay of the ion.

Collision cell for an MS/MS mass spectrometer

One virtual rod electrode is composed by a plurality of electrode plane plates arranged in the ion optical axis direction, and four virtual rod electrodes are arranged around the ion optical axis to form a virtual quadrupole rod type ion transport optical system (). In one virtual rod electrode, the interval between the adjacent electrode plane plates is set to be large in the anterior area (A) and small in the posterior area (B). As the interval between electrodes becomes larger, high-order multipole field components increase and therefore the ion acceptance is increased, which enables an efficient acceptance of ions coming from the previous stage. On the other hand, if the interval between electrodes is small, the quadrupole field components relatively increase and the ion beam's convergence is improved. Therefore, ions can be effectively introduced into a quadrupole mass filter for example in the subsequent stage, which contributes to the enhancement of the mass analysis' sensitivity and accuracy.

In a mass spectrometer, an ion of a sample gas is produced in an ion source by colliding the gas with an electron beam, and is introduced into a magnetic field or an electric field. The ion is separated based on the mass number, and the sample is analyzed from a mass spectrum. The ion source has an electrode made of stainless steel, which is baked at a temperature in a range from 200&#xb0; C. to 700&#xb0; C. in an air atmosphere.

Method of preparing and reconditioning an electrode of mass spectrometer

A quadrupole mass spectrometer includes: an ion source for generating ions; a quadrupole mass filter for selectively passing object ions having a predetermined mass number among the ions from the ion source; an ion detector for detecting the object ions; an ion converging lens placed between the quadrupole mass filter and the ion detector; and a voltage source for applying an optimal voltage to the ion converging lens, wherein the voltage has a polarity opposite to that of the object ions and the absolute value of the voltage is larger than that of a voltage at which the converging efficiency of the object ions is the largest. With respect to the overall S/N ratio, the optimal state is achieved when the optimal converging voltage which is greater than the maximum converging voltage is applied to the ion converging lens.

Quadrupole mass spectrometer

A mass spectrometer with an ionizing chamber in which either of an NCI ion source for producing negative ions and a PCI ion source for producing positive ions is placed. The NCI ion source has a first gas inlet and a second gas inlet, while the PCI ion source has only one gas inlet. In the wall of the ionizing chamber are provided a sample gas inlet and a reaction gas inlet. At an end of the sample gas inlet inside of the ionizing chamber is provided a splitter having a first branch and a second branch. When the NCI ion source is placed in the ionizing chamber, the first gas inlet is connected to the first branch, the second gas inlet is connected to the reaction gas inlet inside of the ionizing chamber, and the second branch is left unconnected inside of the ionizing chamber. By adequately adjusting the flow resistances of the first and second branches, a desired portion of the reference gas from the sample gas source can be supplied to the NCI ion source when a calibration is performed. After the calibration is finished, the residual gas and ions in the NCI ion source are evacuated to the ionizing chamber through the first gas inlet, first branch and second branch. When the PCI ion source is placed in the ionizing chamber, the sole gas inlet is connected to the first branch, and the second branch is connected to the reaction gas inlet. The reference gas and the reaction gas are mixed together at the splitter and delivered to the PCI ion source.

In an inventive ion detector, a cylindrical conversion electrode and an electron multiplier are disposed on a vertical axis intersecting an incidence axis of an ion beam at a right angle. The space between the conversion electrode and the electron multiplier is enveloped by a shield electrode having a cylindrical body with its central axis on the vertical axis. By such a configuration, the electric field which is symmetrical with respect to the vertical axis is generated in the above space, so that secondary electrons or positive ions emitted from the conversion electrode as a result of a secondary emission, travel toward the electron multiplier, converging in proximity to the vertical axis. Thus, most of the secondary electrons or positive ions are led to the electron multiplier with its entrance placed on the vertical axis.

Growing community of inventors

Kyoto, Japan

Hiroto Itoi