JPH03250545A - Mass spectrometer - Google Patents

Abstract

PURPOSE:To sense mass spectrum over a wide range without causing enlargement of device size by energizing a Q-pole lens interposed between an ion source and magnetic field when an array sensor is inserted, and forming an intermediate image on the surface of the lens. CONSTITUTION:In the case measurement is made by sweeping by use of an ion sensor 4, an array sensor 6 is positioned out of the ion passage, and a switch 8 is turned to the grounding side, and a Q-pole lens 5 does not function as lens. Thus pos. ions from an ion source 1 pass through an electric field 3 to reach the sensor 4. In the case measurement is made with simultaneous sensing, the array sensor 6 is inserted, and switch 8 is turned, and a voltage is impressed on the lens 5 from power supplies 7a, 7b. The lens intensity is set properly by adjusting the voltage, and pos. ions from the ion source can be converged at the surface of the array sensor 6. That is, ions spread according to the mass-electric charge ratio in the magnetic field are incident to the array sensor 6 as spectrum and sensed simultaneously.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a mass spectrometer equipped with an array detector.

[Prior art] Magnetic field mass spectrometers are sweep-type mass spectrometers that use a single ion detector to obtain a mass spectrum by sweeping a magnetic field, and array detectors with spatial resolution that obtain mass spectra by a magnetic field. Mass spectrometers are broadly classified into simultaneous detection type mass spectrometers that simultaneously detect analyte ions that are expanded according to their masses.

Traditionally, sweep-type mass spectrometers have been the mainstream in development, but compared to sweep-type mass spectrometers in which ions other than those that reach the ion detector are discarded, simultaneous-detection types that detect all analyte ions simultaneously are better. In principle, it is superior in terms of sensitivity.

Incidentally, as shown in FIG. 5, a so-called inverted mass spectrometer in which an ion source, a magnetic field, an electric field, and an ion detector are arranged in this order has recently been used.

In the figure, 1 is an ion source, and ions with a mass-to-charge ratio ionized by the ion source 1 pass through a magnetic field 2 and an electric field 3,
It is developed on the slit according to the mass-to-charge ratio. and,
A mass spectrum signal can be obtained from the ion detector 4 by sweeping the magnetic field.

[Problems to be solved by the invention] When using such an inverted mass spectrometer and replacing the ion detector with an array detector for simultaneous detection, although the sensitivity increases, ions collide with the electrodes. Since only ions with a narrow mass range can pass through the electric field, a mass spectrum with a wide mass range cannot be obtained. Therefore, it is possible to widen the electric field gap in order to widen the mass range, but widening the gap increases the electric field and increases the size of the device.Also, in order to maintain the strength of the electric field, a higher voltage is required. Therefore, it is difficult to maintain the performance necessary for the electric field power source of a mass spectrometer, such as stable and fast response (required for spectrum measurement using ion acceleration voltage sweep), and the power source also becomes larger. do.

The present invention has been made in view of the above, and an object of the present invention is to provide an inverted mass spectrometer that can detect mass spectra over a wide mass range with an array detector without increasing the size of the device. It is something.

[Means for Solving the Problems] In order to achieve the above object, the first mass spectrometer of the present invention includes an ion source, a magnetic field into which ions generated by the ion source are incident, and an ion emitted from the magnetic field. In a mass spectrometer consisting of an electric field into which ions are incident, and an ion detector that detects ions emitted from the electric field, simultaneous detection is provided that is substantially removably placed on the ion path between the magnetic field and the electric field. When a second type ion detector, a Q pole lens placed on the ion path between the ion source and the magnetic field, and a simultaneous detection type second ion detector are inserted on the ion path,
The present invention is characterized in that a power source is provided for energizing the Q-pole lens so as to move the ion intermediate image convergence surface between the magnetic field and the electric field to coincide with the surface of the second ion detector of simultaneous detection type.

A second mass spectrometer of the present invention includes an ion source, a magnetic field into which ions generated by the ion source enter, an electric field into which ions emitted from the magnetic field enter, and an ion detection system that detects ions emitted from the electric field. A mass spectrometer consisting of a Q-pole lens and a plurality of Q-pole lenses provided on the ion path between the ion source and the magnetic field, which can be inserted and removed from the ion path between the magnetic field and the electric field. A simultaneous detection type second ion detector is installed in the ion path, and when the simultaneous detection type second ion detector is inserted on the ion path, the ion intermediate image focusing surface between the magnetic field and the electric field is moved to perform simultaneous detection. The present invention is characterized in that the intensity of the Q-pole lens provided between the ion source and the magnetic field is changed so as to match the surface of the second ion detector of the type.

[Operation] In the present invention, an array detector is removably disposed on an intermediate image focusing surface between a magnetic field and an electric field, so that a spectrum can be detected. When the array detector is placed in this position, the resolution will be slightly degraded due to single focusing, but since the ions are not obstructed by the electrodes, a wide range of mass spectra can be obtained with high sensitivity. If the detector is removed, sweep measurements can be performed as before. However, normally the interval between the intermediate image convergence surface and the electric field is narrow, and even if an array detector is arranged, the convergence surface will not coincide with the surface of the array detector. Therefore, in the present invention, a Q-pole lens is provided on the ion path between the ion source and the magnetic field, and when the array detector is inserted onto the ion path, the Q-pole lens is energized and the intermediate image is focused on the convergent surface. is brought close to the magnetic field to form an intermediate image on the surface of the array detector.

[Example] Embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is a diagram showing the main parts of an apparatus according to an embodiment of the present invention,
In FIG. 1, the same numbers as those used in FIG. 5 indicate the same components.

The device shown in Fig. 1 is different from the conventional example shown in Fig. 5 as follows.
A Q-pole lens 5 is provided on the ion path between the ion source 1 and the magnetic field 2, and an array detector 6 is removably provided on the ion path between the magnetic field 2 and the electric field 3. Note that the Q pole lens 5 has a switch 8 that operates in conjunction with the Q pole lens 5.
It is configured such that voltage can be applied from power supplies 7a and 7b via a and 8b.

As shown in FIG. 2, the electrostatic quadrupole lens forming the Q-pole lens 5 is composed of four electrodes 9 to 12 arranged at 90 degree intervals, and is connected to a power source 7a.

7b to each electrode 9°10. through switches 8a and 8b.
Positive and negative voltages are applied to 11 and 12. As a result, a potential distribution is obtained in which the ion flow (assuming positive ions) is converged in the radial direction (X direction) and diverged in the direction perpendicular to the orbital plane (X direction).

In such a configuration, when performing sweep measurement (sweep mode) using the ion detector 4, the array detector 6 is removed from the ion path. Further, since the switches 8a and 8b are turned to the ground side, the Q pole lens does not function as a lens. Then, the positive ions ionized by the ion source 1 form an intermediate image convergence surface near the electric field 3, as described in the conventional example, pass through the electric field 3, and reach the ion detector 4. If a magnetic field sweep is performed in this state, a mass spectrum signal can be obtained from the ion detector 4.

On the other hand, when performing simultaneous detection measurement (simultaneous detection mode), insert the array detector 6 at the dotted line position, switch 8a,
Switch 8b (indicated by the dotted line in the figure) to power supply 7g, 7b
A voltage is applied to the Q ball lens from . In this way, the Q ball lens functions as a convex lens, and the power source 7a,
By appropriately adjusting the output voltages -V and +V 7b and appropriately setting the lens strength, positive ions emitted from the ion source 1 can be focused on the surface of the array detector 60 as shown by the dotted line. That is, ions expanded according to the mass-to-charge ratio by the magnetic field are incident on the array detector 6 as a spectrum and are simultaneously detected.

The above description has been made regarding the case in which positive ions are to be analyzed, but the same effect can be obtained also in the case of negative ions by reversing the polarity of the power supplies 7a and 7b.

FIG. 3 is a diagram showing the essential parts of another embodiment of the apparatus of the present invention, in which the present invention is applied to a mass spectrometer introduced in Japanese Patent Application Laid-open No. 160949/1983.

In this mass spectrometer, an ion source 1, a magnetic field 2, an electric field 3, and an ion detector 4 are arranged in this order. diverges the ion flow in the direction perpendicular to the orbital plane (X direction)
Two Q-ball lenses 13 and 14 are arranged to converge the positive ions, and between the magnetic field 2 and the electric field 3, there is a Q-ball lens 13 and 14 to converge the passing positive ions in the direction perpendicular to the orbital plane (X direction).
A pole lens 15 is arranged.

The electrostatic quadrupole lens that constitutes the Q-pole lens 13 is
As shown in FIG. 4, power supply 16a, 16b or 22a
, 22b, positive and negative voltages are applied to each electrode 18, 19, 20.21 via switches 17a, 17b. And the Q pole lens 14 also has a Q pole lens 1.
3 power supply 16a.

A voltage is applied from a power source 23 having the same configuration as those of 16b, 22a, 22b, 17a, and 17b.

An array detector 6 is removably installed on the ion path between the magnetic field 2 and the electric field 3.

In such a configuration, when performing measurement by magnetic field sweep using the ion detector 4, the switches 17g, 17
b is tilted toward the sweep measurement power supplies 16a and 16b.

The positive ions ionized by the ion source 1 pass through the Q ball lens 13, 14 and the magnetic field 2, form an intermediate image converging surface near the entrance of the electric field 3, and further pass through the electric field 3 to the ion detector 4. reach. A mass spectrum signal is obtained from the ion detector 4 by performing magnetic field sweeping.

Next, in the simultaneous detection mode, the array detector 6 is inserted at the dotted line position, and the switches 17a and 17b are turned to the simultaneous detection power supplies 22a and 22b (indicated by dotted lines in the figure). The voltage applied to the Q ball lens from the simultaneous detection power supplies 22a and 22b has a lower absolute value or a voltage of opposite polarity than the voltage applied from the sweep measurement power supplies 16a and 16b in order to weaken the lens strength. It is set. The Q-pole lenses 13 and 14 act as concave lenses when it comes to forming intermediate images of ions, and as a result of weakening the lens strength, the positive ions emitted from the ion source 1 are directed to the array detector 6 as shown by the dotted line. An intermediate image is formed on the surface of the object and detected simultaneously.

In the device of the embodiment described above, the array detector was moved above the ion path, but by providing a deflection field between the magnetic field and the electric field to bend the ion flow, the array detector could be fixedly placed outside the ion path. An intermediate image may be formed on the surface of the array detector, in other words, the array detector may be inserted and removed substantially on the ion path.

[Effects] As detailed above, according to the present invention, it is not necessary to widen the electric field gap or use high voltage in order to obtain a mass spectrum over a wide mass range, so the device does not become large. An inverted mass spectrometer is realized that can easily switch between a simultaneous detection mode that allows high-sensitivity measurement over a wide mass range and a sweep measurement mode that allows high-resolution measurement.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the main parts of an apparatus according to an embodiment of the present invention, FIG. 2 is a configuration diagram of a Q-pole lens used in the embodiment of FIG. 1, and FIG. 3 is a diagram showing another embodiment of the present invention. FIG. 4 is a block diagram of the Q-ball lens used in the embodiment shown in FIG. 3, and FIG. 5 is a diagram showing the main parts of a conventional device. 1: Ion source 2: Magnetic field 3: Electric field 4: Ion detector 5.13.1
4, 15: Q pole lens 6: Array detector 7a, 7b, 22a, 22b: Power supply 8a, 8b, 17a, 17b: Switch 9-12.18
~21: Electrode

Claims (2)

[Claims] (1) Mass spectrometry consisting of an ion source, a magnetic field into which ions generated by the ion source are incident, an electric field into which ions emitted from the magnetic field are incident, and an ion detector which detects the ions emitted from the electric field. a simultaneous detection type second ion detector disposed substantially removably on the ion path between the magnetic field and the electric field; and a second ion detector disposed on the ion path between the ion source and the magnetic field. When the Q-pole lens and the second ion detector of the simultaneous detection type are inserted on the ion path, the ion intermediate image focusing surface between the magnetic field and the electric field is moved and the surface of the second ion detector of the simultaneous detection type is moved. A mass spectrometer characterized in that a power source is provided to energize a Q-pole lens so as to match the Q-pole lens. (2) An ion source, a magnetic field into which ions generated by the ion source are incident, an electric field into which ions emitted from the magnetic field are incident, an ion detector which detects ions emitted from the electric field, and an ion source and a magnetic field. In a mass spectrometer consisting of a plurality of Q-pole lenses provided on the ion path between the magnetic field and the electric field, a simultaneous detection type second lens is substantially removably inserted onto the ion path between the magnetic field and the electric field. An ion detector is provided, and when the simultaneous detection type second ion detector is inserted on the ion path, the ion intermediate image focusing surface between the magnetic field and the electric field is moved to move the simultaneous detection type second ion detector. A mass spectrometer characterized in that the intensity of a Q-pole lens provided between an ion source and a magnetic field is changed so as to match a surface.