JP3096375B2 - Hybrid tandem mass spectrometer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a so-called tandem mass spectrometer in which two mass spectrometers are connected, in particular, a magnetic field type mass spectrometer as a first mass spectrometer and a quadrupole as a second mass spectrometer. The present invention relates to a hybrid tandem mass spectrometer using a mass spectrometer.

[0002]

2. Description of the Related Art FIG. 1 shows an example of a hybrid tandem mass spectrometer. In FIG. 1, 1 is an ion source, 2 is a double focusing mass spectrometer composed of an electric field and a magnetic field into which ions generated by the ion source 1 are incident, and 3 is a specific mass-to-charge ratio that has passed through the double focusing mass analyzing system. 4 is a collector slit in which the ions having the convergence are converged, and 4 is a quadrupole mass spectrometer into which the ions passing through the collector slit 3 are introduced.
Is a connection lens system for connecting the double converging mass spectrometry system 2 and the quadrupole mass spectrometer 4, and includes a converging lens 6 and a deceleration lens 7.
Consists of

Generally, the kinetic energy of ions handled by a quadrupole mass spectrometer is two to three orders of magnitude smaller than the kinetic energy of ions handled by a magnetic field mass spectrometer. Therefore, in the hybrid tandem mass spectrometer, it is necessary to decelerate the ions that have passed through the magnetic field type mass spectrometer and to introduce the ions into the quadrupole mass spectrometer. That is, the center path of the ions of the magnetic field type mass spectrometry system 2 is set to the ground potential, but in the quadrupole mass spectrometer 4, it should be almost the same as the acceleration potential Va in the ion source 1.

FIG. 2 schematically shows a potential distribution along an ion path in the hybrid tandem mass spectrometer of FIG. Quadrupole mass spectrometer 4
Deceleration lens 7 to give potential Vb to
And a converging lens 6 is used to converge ions diverging through the collector slit 3 toward the deceleration lens 7. Note that the difference between the potentials Vb and Va in the quadrupole mass spectrometer 4 defines the kinetic energy of ions flying in the quadrupole mass spectrometer.

Conventionally, an Einzel lens having a structure as shown in FIG.
As the deceleration lens 7, an axially symmetric lens having a structure as shown in FIG. 3B is used.

[0006]

However, the conventional connection lens system has a low ion passing efficiency, and it has been difficult to introduce a large amount of ions into a quadrupole mass spectrometer.
Therefore, measurement with high sensitivity was difficult.

The present invention has been made in view of the above points, and is a hybrid tandem in which ions selected by a magnetic field type mass spectrometer can be efficiently introduced into a quadrupole type mass spectrometer and analyzed with high sensitivity. It is intended to provide a mass spectrometer.

[0008]

In order to achieve this object, the present invention provides a hybrid tandem mass spectrometer in which a quadrupole mass spectrometer is connected after a magnetic field mass spectrometer. A rotationally symmetric deceleration lens is arranged between the collector slit and the quadrupole mass spectrometer, and between the deceleration lens and the collector slit,
A convergent lens combining two or more quadrupole lenses is provided.

[0009]

According to the present invention, a rotationally symmetric deceleration lens is disposed between the collector slit of the magnetic field type mass spectrometer and the quadrupole mass spectrometer, and two or more deceleration lenses are provided between the deceleration lens and the collector slit. Since the converging lens in which the quadrupole lens is combined is arranged, the ion beam having a rectangular cross section passing through the collector slit can be converted into an ion beam having a circular cross section and introduced into the deceleration lens. Therefore, ions that have passed through the collector slit can be efficiently introduced into the quadrupole mass spectrometer. Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

[0010]

FIG. 4 is an ion optical diagram showing one embodiment of the present invention, and the same components as those in the conventional example of FIG. 1 are denoted by the same reference numerals. The embodiment of FIG. 4 differs from the conventional example of FIG. 1 in that a lens comprising quadrupole lenses Q1 and Q2 is used as the converging lens 6.

FIG. 5 is a view for explaining the state of the ion beam in the portion of the collector slit 3 and the connecting lens system 5. 5A shows the width direction of the collector slit 3 (X direction: the radial direction of the ions in the double focusing mass spectrometer 2), and FIG. 5B shows the length direction of the collector slit 3 (perpendicular to the X direction). FIG. 5C is a cross-sectional view at the position of the collector slit, the positions of the quadrupole lenses Q1, Q2 and the lens 7, respectively.

FIG. 5 shows that the quadrupole lens Q1 has convergence (divergence in the X direction) in the Y direction and the quadrupole lens Q2 has divergence (convergence in the X direction) in the Y direction.
A voltage having a polarity as shown in FIG. 4C is applied to each electrode constituting the quadrupole lenses Q1 and Q2.

Then, the absolute value of the voltage is appropriately selected, and Q 1,
By properly setting the lens strength of Q2, an ion beam having a rectangular cross section with a very narrow width at the collector slit portion has an ion beam having a substantially circular cross section at the time of exiting the lenses Q1 and Q2. Shaped into a beam. For this reason, ions can be efficiently introduced into the quadrupole mass spectrometer 4 that handles an ion beam having a circular cross section via the axis-symmetric deceleration lens 7.

The number of quadrupole lenses may be two or more. One of the quadrupole lenses must have at least convergence in the Y direction (divergence in the X direction). is there.

[0015]

As described in detail above, according to the present invention,
A rotationally symmetric deceleration lens is arranged between the collector slit of the magnetic field type mass spectrometer and the quadrupole type mass spectrometer, and two or more quadrupole lenses are combined between the deceleration lens and the collector slit. Since the convergent lens is arranged, the ion beam having a rectangular cross section that has passed through the collector slit can be converted into an ion beam having a circular cross section and introduced into the deceleration lens. Therefore, the ions that have passed through the collector slit can be efficiently introduced into the quadrupole mass spectrometer, and a hybrid tandem mass spectrometer capable of high-sensitivity analysis is realized.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of a hybrid tandem mass spectrometer.

FIG. 2 is a diagram schematically showing a potential distribution along an ion path in the hybrid tandem mass spectrometer of FIG.

FIG. 3 is a diagram for explaining the structures of a converging lens 6 and a decelerating lens 7;

FIG. 4 is an ion optical diagram showing one embodiment of the present invention.

FIG. 5 is a diagram for explaining a state of an ion beam in a portion of a collector slit 3 and a connection lens system 5;

[Explanation of Signs] 1 Ion source 2 Double focusing mass spectrometer 3 Collector slit 4 Quadrupole mass spectrometer 5 Connecting lens system 6 Converging lens 7 Reduction lens

Claims (1)

(57) [Claims] In a hybrid tandem mass spectrometer in which a quadrupole mass spectrometer is connected after a magnetic field mass spectrometer, rotational symmetry is provided between a collector slit of the magnetic field mass spectrometer and the quadrupole mass spectrometer. Along with disposing a deceleration lens, between the deceleration lens and the collector slit,
A hybrid tandem mass spectrometer comprising a convergent lens in which two or more quadrupole lenses are combined.