Shimadzu Corporation

Hiroaki Waki

Li Ding

Roger Giles

Masahiro Hiraishi

Shinichi Kuroda

Sadao Takeuchi

Mayumi Matsui

Toshihiko Yoshida

Sunao Yoshida

Hideo Satta

Norihito Inatsugu

The present invention provides a mass spectrometer having an ion lens capable of transporting an ion having a large mass to charge ratio with a high level of ion-passing efficiency even under a low-vacuum atmosphere. In conventional atmospheric pressure ionization mass spectrometers or similar mass spectrometers, applying an excessively high voltage to the ion lens undesirably causes an electric discharge. Therefore, the passing efficiency for an ion having a large mass to charge ratio cannot be adequately improved, which leads to a poor detection sensitivity. To solve this problem, the mass spectrometer according to the present invention includes a voltage controllerthat controls a variable radiofrequency (RF) voltage generatorso that both the amplitude and the frequency of the RF voltage applied to the lens electrodes of an ion lensare changed according to the mass to charge ratio of an ion to be analyzed. This control enables the ion lensto focus an ion and transport it to the subsequent stage with a high level of passing efficiency even in the case of analyzing an ion having a large mass to charge ratio. Thus, the detection sensitivity is improved. The aforementioned control is conducted on the basis of the control data stored in a voltage control data storage. These data are obtained in advance by a measurement of a sample containing a substance having a known mass to charge ratio, in which the intensity of the signal of an ion detector is maintained while the analysis conditions are changed.

Mass spectrometer

An atmospheric pressure ionization mass spectrometry system has an atmospheric pressure ionization chamber for ionizing a sample, an evacuated intermediate evacuation chamber into which generated ions are introduced through a capillary tube, and a vacuum chamber further downstream therefrom into which ions are introduced for mass separation. A partition wall separating the atmospheric pressure ionization chamber from the intermediate evacuation chamber includes a small orifice having a diameter corresponding to an internal channel diameter of the capillary tube. The capillary tube is detachably installed on the partition wall so that an outlet end of the capillary tube abuts on the small orifice. The internal channel of the capillary tube is in communication with the small orifice. The capillary tube can be installed and removed from the system without breaching the vacuum.

Atmospheric pressure ionization mass spectrometer system

A liquid chromatography/mass spectrometry apparatus combines a chromatograph having a liquid delivery part for delivering mixed multiple solvents, and a mass spectrometer having an ionization part for spraying and ionizing. The apparatus has a storing part for storing a relationship between a mixture ratio of the multiple solvents in the liquid delivery part and an optimal or nearly optimal voltage applied to the ionization part, a ratio information acquiring part for computing the mixture ratio over time, a voltage value computing part for computing the optimal or nearly optimal applied voltage at any point, and a voltage controlling part for changing the voltage applied to the ionization part over time. By virtue of the ability to adjust the applied voltage during analysis, the ionization efficiency is always high, and the analysis can be performed with high sensitivity for all of the multiple components in the liquid sample.

Liquid cheromatography/mass spectrometry apparatus

The preparative liquid chromatograph uses a plurality of detectors including a mass spectrometer, and a chromatogram generator is provided for generating a plurality of chromatograms each corresponding to each of the plurality of detectors. The plurality of chromatograms are converted into a respective binary signal by comparing the chromatogram with a predetermined threshold, and a logical operator performs a binary operation on the plurality of respective binary signals, whereby a resultant binary signal is generated. A separation controller controls the fraction collector of the preparative liquid chromatograph based on the resultant binary signal to separate components from a sample. When 'AND' is used as the binary operation, the resultant binary signal is '1' only when all the respective binary signals are &#x201c;1&#x201d;. This assures a high precision, high purity separation where an impurity mingling is minimized. When &#x201c;OR&#x201d; is adopted as the binary operation, the resultant binary signal is &#x201c;1&#x201d; when a component is detected by any of the plurality of detectors. This assures separation of as many components as possible appearing in the chromatograms generated by the detectors.

Preparative liquid chromatograph using plural detectors

A mass spectrograph has an ionization chamber for ionizing a sample, a skimmer in a conical shape with an orifice and a bottom opening, an analyzing chamber at a lower pressure than inside the ionization chamber such that ions generated in the ionization chamber are pulled through the orifice into the analyzing chamber, and a multi-pole ion guide disposed proximally behind the skimmer. The ion guide has an even number of cylindrically shaped electrodes all elongated in the axial direction of the skimmer and the ion guide and disposed so as to circumscribe an inscribed circle and such that the conical surface of the skimmer, when extended, intersects the internally facing side surfaces of the electrodes, not their front surfaces facing the skimmer. Thus, the generated ions can reach the analyzing chamber more efficiently.

Mass spectrograph

In a liquid chromatograph mass spectrometer, a solvent removing tube provided substantially horizontally between a spray chamber and a subsequent chamber is bent at an obtuse angle such that an entrance side of the tube is directed downwardly, and a nozzle is disposed such that a spraying direction of the nozzle is directed substantially downwardly and is approximately perpendicular to a central axis of the entrance side of the tube. Further, a drain for droplet or liquid is provided in front of the spraying direction of the nozzle. Since the spraying direction is oblique to a partition wall, the droplet or liquid sprayed from the nozzle collides against the drain, so that the droplet do not bounce to the entrance side of the solvent removing tube. Accordingly, the noise can be prevented, and the memory effect is also reduced in a high-density sample, so that an accurate analysis can be conducted.

Liquid chromatograph mass spectrometer

In a mass spectrometer, electrode element plates forming a virtual rod electrode have predetermined shapes at rim portions thereof in an ion optical axis side, and the electrode element plates are held at portions away from the ion optical axis by a holder, to thereby form a virtual rod multipole ion lens unit. Also, apart from the ion lens unit, there is provided a terminal unit for applying predetermined voltages to the respective electrode element plates. In the ion lens unit, the electrode element plates to which the same potential is applied are respectively connected by immovable short lines to form the groups. One of the electrode element plates in each group is electrically connected to the terminal unit.

Mass spectrometer with multipole rod type ion lens

A mass spectrometer according to the present invention includes an ion lens composed of an even number of virtual rod electrodes positioned separately around the ion beam axis C, where each of the virtual rod electrodes is composed of a plurality of separate metallic plate electrodes aligned in a row. For example, the virtual rod electrode consists of five lens electrodes aligned in a row parallel to the ion beam axis C. A voltage composed of a DC voltage and a high frequency AC voltage superimposed thereon is applied to each of the plate electrodes where the DC voltage is changed according to the position of the plate electrode while the high frequency AC voltage is the same irrespective of the position. Ions travelling through the ion lens oscillates transversally due to the electric field generated by the high frequency AC voltage and converge on the focal point F of the ion lens. There, the ions gain kinetic energy from the potential gradient due to the DC voltages, whereby the ions are accelerated. Thus, the ions keep travelling without being displaced too much from due converging paths even when they collide with molecules of residing gas, and enter the section behind the ion lens through the orifice of the skimmer Thus, the convergence and acceleration of ions are effectively performed even when the pressure in the first interface chamber is as high as near atmospheric pressure.

An electrospray ionizer which enables the operator to adjust the position of the glass capillary with respect to the metal tube to which a high voltage is applied while the sample solution is being nebulized and ionized at the fore end of the glass capillary. The electrospray ionizer is composed of: a glass capillary for allowing the sample solution to flow out from its fore end; a metal tube surrounding the fore end part of the glass capillary for generating an irregular electric field at around the fore end of the glass capillary; a first pipe, or a guide pipe, made of a non-conductive material for holding the back end of the metal tube and extending backward; a second pipe, or a seal pipe, for loosely holding the glass capillary further back along the first pipe; and a joint for connecting the first pipe and the second pipe. Consequently, the position of the glass capillary is loosely fixed with respect to the metal tube. Thus by manipulating the back end of the glass capillary to slide the glass capillary in the second pipe, it is possible to change the position, or the length of the extension d, of the fore end of the glass capillary with respect to the metal tube. This enables the operator to adjust the extension d so that the amount of ions generated at the fore end of the glass capillary is at its maximum while the electrospray ionizer is working and the metal tube has a high voltage applied to it, whereby the sensitivity of the liquid chromatograph using the electrospray ionizer of the present invention is greatly improved.

Electrospray ionizer

A quadrupole mass filter, or a multiple-pole mass filter in general, composed of a cylindrical main body made of an insulating material and having a star-shaped cross-sectional profile whose inward bulges are curved substantially hyperbolic, and four electrode layers of a high melting point metal deposited by a chemical vapor deposition (CVD) process. The four electrode layers are separated at the outward bulges of the star-shaped cross-sectional profile. The quadrupole mass filter has pre-rod electrodes.

Cylindrical multiple-pole mass filter with CVD-deposited electrode layers

A mass spectrometric apparatus receives a liquid sample from a liquid chromatograph, ionizes it under an atmospheric condition and guides these ions from the liquid sample along a specified trajectory through one or more intermediate vacuum chambers to a mass analyzer kept inside a high vacuum chamber. At least one of these intermediate vacuum chambers is kept in an intermediate vacuum condition in the so-called viscous flow region and contains at least one pair of mutually separated planar electrodes sandwiching the trajectory. Voltages of the same polarity as that of the ions which are passed through are adjustably applied to the electrodes so as to form a converged ion beam and also to control its trajectory. Two mutually perpendicular pairs of such electrodes may be disposed across the trajectory. Two sets each with two such pairs of electrodes may be disposed across the trajectory.

Mass spectrometric apparatus for use with a liquid chromatograph

A quadrupole mass analyzer in which a pair of heat sink plates 16, 17 and springs 18 clamp ceramic holders 13, 14 that hold the four rod electrodes 12 of the quadrupole unit. The dielectric heat generated in the ceramic holders 13, 14 by the high frequency alternating electromagnetic field due to the AC voltage applied on the four rod electrodes 12 is promptly transferred to the heat sink plates 16, 17. Thus displacement of the four rod electrodes 12 or loss of symmetry is prevented when mass of ions is analyzed.

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Kyoto, Japan

Hiroaki Waki