Shimadzu Corporation

Manabu Ueda

Kota Nagasao

Daisuke Okumura

Yuki Tanaka

Tomohito Nakano

Wataru Fukui

Jun Watanabe

Shinjiro Fujita

Masateru Oguri

Takashi Umemoto

After performing an analysis on a standard sample for a predetermined time, a plurality of ion optical elements such as an ion guide are sequentially selected one by one, and a direct-current voltage having a polarity different from that at the time of analysis is temporarily applied. Meanwhile, intensity data of ions having a specific m/z are continuously collected. After thus collecting the data, the ratio of the ion intensities before and after application of direct-current voltages having different polarities is calculated for each ion optical element, and it is determined whether or not the ratio is equal to or larger than a predetermined threshold value.

Mass spectrometer

A single type quadrupole mass spectrometer equipped with an ion source by the ESI method, which is a small device including a vacuum pump having a relatively small evacuation speed. The internal diameter of a desolvation tube for introducing ions from an ionization chamber into a first intermediate vacuum chamber is set to 0.4 mm &#x3c6;, which is large for a small mass spectrometer. The evacuation speed of a rotary pump is determined so that the product of the cross-sectional opening area of the desolvation tube and the pressure in the first intermediate vacuum chamber falls within a range of 15 to 40 mm&#xb7;Pa. This can ensure high detection sensitivity and reduce clogging of the desolvation tube due to droplets. Since the pressure in the first intermediate vacuum chamber does not need to be increased more than necessary, a small rotary pump having a small evacuation speed can be used.

A mass spectrometer adopting a configuration of a multi-stage differential evacuation system appropriately performs optimization of a direct-current voltage applied to a plurality of ion optical elements for transporting ions. An auto-tuning controller acquires intensity data of ions derived from a predetermined component while changing a direct-current voltage applied to ion guides and the like, and searches for a direct-current voltage at which the intensity is maximized. When the direct-current voltage applied to a certain ion optical element is changed at the time of automatic adjustment, the direct-current voltage applied to all the ion optical elements thereafter is also changed by the same amount. Since the direct-current voltage difference between two adjacent ion optical elements always changes at only one point, the direct-current potential difference can be determined so as to optimize the ion passage efficiency.

A quadrupole mass filter includes: four electrodes arranged to surround a central axis and constituting a quadrupole; attachment portions to which a plurality of electrical conductors are attached, at least one of the electrical conductors being arranged at a position that lies in a direction toward an area between each of the adjacent electrodes among the four electrodes, as viewed from the central axis; and a holder having a hollow portion and holding the four electrodes and the plurality of electrical conductors, wherein the electrical conductors are attached to the respective attachment portions and held by the holder with elasticity of a material constituting the electrical conductors.

Quadrupole mass filter and analytical device

A vacuum chamberfor forming a vacuum space has two side walls opposite to each other across an ion beam axis extending within the vacuum space. One of those side walls is openable and closeable. An ion optical elementis placed on a base, which is located on the bottom surface of the vacuum chamber. A fixation bandfixes the ion optical element on the base by holding the element between the base and the fixation band so as to press the element onto the base. A band-catching portion, located on an inside face of a side wall of the vacuum chamber on the opposite side from the openable-and-closeable side wall, catches one end of the fixation band. A band-fixing portion, located on the base on the side where the openable-and-closeable side wall is present, fixes the other end of the fixation band to the base.

Four rod electrodes (to) for separating ions according to a mass-to-charge ratio are held by a rod holder (). The rod holder () is placed on a metal holder sustaining stand () provided on a bottom surface of a vacuum housing (), and is fixed while being pressed by a fixation band () fixed to the holder sustaining stand () with screws (). The fixation band () has a coating film layer () formed by a black nickel plating process on the entire surface of a main member () made from phosphor bronze. The coating film layer () has high emissivity, and thus heat transferred from the rod holder () to the fixation band () is efficiently radiated into the vacuum housing (). Therefore, heat generated in the rod holder () due to dielectric loss is efficiently dissipated, and deformation of the rod holder can be reduced.

Four rod electrodes (to) for separating ions according to a mass-to-charge ratio are held by a rod holder (). The rod holder () is placed on a metal holder sustaining stand () provided on a bottom surface of a vacuum housing (), and is fixed while being pressed by a fixation band () fixed to the holder sustaining stand () with screws (). The fixation band () is made from phosphor bronze having higher thermal conductivity than thermal conductivity of stainless steel or the like. Therefore, heat generated in the rod holder () due to dielectric loss is not only directly transmitted to the holder sustaining stand (), but also efficiently transmitted to the holder sustaining stand () through the fixation band (). With this, the heat of the rod holder () is efficiently dissipated, and non-uniformity of temperature of the rod holder can be reduced.

Mass spectrometer including a fixation band

Four rod electrodes (to) for separating ions according to a mass-to-charge ratio are held by a rod holder (). The rod holder () is placed on a metal holder sustaining stand () provided on a bottom surface of a vacuum housing (), and is fixed while being pressed by a fixation band () fixed to the holder sustaining stand () with screws (). A heat release layer () made from heat dissipation silicone or the like is inserted between the fixation band () and the rod holder () and between the fixation band () and the holder sustaining stand (). Therefore, heat generated in the rod holder () due to dielectric loss is not only directly transmitted to the holder sustaining stand (), but also efficiently transmitted to the holder sustaining stand () through the fixation band ().

An ionizer includes an ionization probe () provided with a capillary (), a metallic slender tube (), and a nebulizing gas pipe (). The ionization probe () is equipped to perform ESI-based ionization of components in a liquid sample. An electroconductive capillary () is disposed at a position forward in a flow direction of a nebulized flow of the liquid sample from the ionization probe (). A high voltage from a high voltage power supply () is applied to the electroconductive capillary () to induce corona discharge so that the components in the liquid sample are ionized by the APCI as well. At the time of tuning the ionizer, a standard sample solution is provided through the electroconductive capillary (), and a high voltage from the high voltage power supply () is applied to the electroconductive capillary () so that components in the standard sample solution are ionized by the ESI or due to an ion molecular reaction with solvent molecular ions produced in the ionization probe (). Thus, components in a standard sample can be ionized and subjected to mass spectrometry without pipe rearranging operations or without switch to and from different flow paths using a valve.

Ionizer and mass spectrometer

Four rod electrodes (to) for separating ions according to a mass-to-charge ratio are held by two rod holders (). The rod holders () are attached to metal holder sustaining stands () provided on a bottom surface of a vacuum housing (). A coating film layer () is formed by a black nickel plating process on parts of wall surfaces in the vacuum housing (), an inlet lens (), and an outlet lens (), the parts facing a quadrupole mass filter unit (). The emissivity of the coating film layer () is higher than that of Al or the like, and thus radiant heat from the quadrupole mass filter unit () is efficiently absorbed by the coating film layer (). Therefore, heat generated in the rod holders () due to dielectric loss is efficiently dissipated, and deformation of the rod holders can be reduced.

The detection of minute amounts of components that have been undetectable due to an influence of a mobile phase or reagents or the like added to the mobile phase is realized in LC-MS. At the outset, blank measurement is executed, and an m/z value Mof a background signal derived from a mobile phase or the like is extracted on a mass spectrum obtained by the blank measurement (S-S). An analysis method is then created that executes scanning measurement in a plurality of divided m/z ranges in which the m/z value Mof the background signal has been excluded from a predetermined m/z range. An LC/MS analysis of the target sample is executed according to the analysis method (S-S). When a total ion chromatogram (TIC) is created from data obtained by the LC/MS analysis, influence of the background signal hardly appears in the TIC, and the base line is lowered.

Analysis device

In the mass spectrometer system, a tip portion of a cylindrical portion () of a capillary () is coated with a coating material (), the tip portion being an injection part for injecting a sample solution to an ionization section. Therefore, it is possible to suppress, by the coating material (), the deformation of the capillary () when the sample solution is injected. In addition, it is possible to suppress the corrosion and the deformation of the capillary () by the coating material (). As a result, the stability of the analysis operation in mass spectrometer system () can be improved.

Ionizer and mass spectrometer system

A dwell time calculation table () showing a correspondence relation between a CID gas pressure inside a collision cell () and a dwell time for data collection is stored in a processing condition parameter memory () of a controller (). In the table (), as the CID gas pressure becomes higher, the dwell time becomes longer. When an instruction to execute an MRM measurement mode is given, the controller () determines the dwell time in accordance with the currently set CID gas pressure, and controls a data collector () to accumulate detection signals from an ion detector () during the determined dwell time and obtain the accumulated value. If the CID gas pressure inside the collision cell () is high, a decrease in ion speed becomes remarkable, and the rising of the ion intensity becomes slow. However, if the dwell time becomes long, influences of the slow rising on the accumulated value are relatively reduced, and the accuracy of the accumulated value is enhanced. Accordingly, the quantitative accuracy can be enhanced.

Tandem quadrupole mass spectrometer

A chromatograph mass spectrometer including an optimum gas pressure search controller that performs an MRM measurement for a target compound while changing a collision-gas pressure, investigates an optimum collision-gas pressure giving a highest signal strength based on the measured result, and stores the same gas pressure for each compound in a compound-related information storage section. When a target compound is specified in a simultaneous multicomponent analysis, a control sequence determiner reads the optimum collision-gas pressure and retention time information corresponding to the specified compound from the storage section, prepares a control sequence which sets the gas pressure in a collision cell at the optimum gas pressure at the timing where each compound is eluted, and stores the sequence in a control sequence storage section.

Chromatograph mass spectrometer

The present triple quadrupole mass spectrometer determines the relationship between a parameter, such as the mass-to-charge ratio of a precursor ion or that of a product ion, and the optimal collision-gas pressure giving the highest signal intensity in an MRM measurement, derives an approximate equation expressing that relationship, and stores the information representing the equation in an optimum collision-gas pressure calculation information storage section. When a measurement is to be performed, an analysis operator enters the mass-to-charge ratio of a precursor ion or product ion of a target compound. Based on the approximate equation read from the storage section, an optimum collision-gas pressure calculator determines the optimum collision-gas pressure for the specified precursor ion or product ion, and sets this pressure as a measurement condition for the apparatus.

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Kyoto, Japan

Manabu Ueda