JP2883935B2 - Tandem mass spectrometer - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a tandem mass spectrometer, and in particular, to a first tandem mass spectrometer.
The present invention relates to an acceleration voltage applying means suitable for adjusting the mass number determination accuracy of a mass spectrometer of a second stage and a mass spectrometer of a second stage.

[Related Art] A tandem mass spectrometer provides powerful information for analyzing a chemical structure of a polymer. The feature is that only the specific parent ion is selected in the first stage mass spectrometer, so that sample isolation is not required, and the dissociated daughter ion analyzed in the second mass spectrometer is separated from another parent ion. Is not mixed.

In a conventional tandem mass spectrometer, two mass spectrometers are connected. For high resolution and high mass range analysis,
As the two mass spectrometers, a double focusing mass spectrometer provided with ion beam direction focusing and energy focusing is often used.

One example is shown in FIG. The first mass spectrometer includes a first ion source 1, a first electric field 3 and a first magnetic field 4 for converging a parent ion 2 emitted from the ion source, and a first mass spectrometer detector in the connection unit 5. 5A. The detected parent ion 2 is dissociated in the collision chamber 5B in the connecting portion 5 by collision with a gas such as fluium, and becomes a daughter ion 17. This daughter ion
The second mass spectrometer for analyzing 17 comprises a second electric field 6 and a second magnetic field 7 for converging daughter ions 17, and a second mass spectrometer detector 8. The connection section 5 includes a second ion source 5C used for performance adjustment of only the second mass spectrometer such as resolution, sensitivity, and mass number determination.

As a power source for each part, the first mass spectrometer includes a first ion source accelerating power source 9, a first electric field power source 10, and a first magnetic field power source 11
Wherein the second mass spectrometer comprises an acceleration power supply for the second ion source.
13, a second electric field power supply 14, and a second magnetic field power supply 15. Also, a first mass spectrometer control unit 12 and a second mass spectrometer control unit 16 for controlling these power supplies and receiving signals from the respective detectors and collecting data.
And

In this type of tandem mass spectrometer, since the first mass spectrometer and the second mass spectrometer are calibrated using the same standard sample, it is necessary to match the mass number determination accuracy of the parent ion and the daughter ion. First, it is necessary to adjust the first acceleration voltage and the second acceleration voltage so that they completely match each other. However, since the voltage is high, it is actually difficult to make them match.

[Problem to be Solved by the Invention] When used as a tandem mass spectrometer, after the specific parent ion 2 is detected by the detector 5A in the connecting portion 5 by the first mass spectrometer, the electric field 3 and the magnetic field 4 Is fixed, and the parent ion 2 is guided to the gas collision chamber 5B in the connection portion 5. Here, the daughter ions 17 dissociated due to the gas collision have different energies and masses due to the dissociation. Therefore, the daughter ions 17 are subjected to mass analysis by a method generally called a B / E linked scan measurement method in the mass spectrometry. In this method, it is possible to determine the mass of only daughter ions dissociated from a specific parent ion by performing linked scanning while keeping the ratio B / E of E of the second electric field 6 and B of the second magnetic field 7 constant. Become. Therefore, it was thought that each electric field and magnetic field needed to have an independent power supply and control unit.

However, the second ion source and the second ion source accelerating power supply 13 in the connecting portion 5 are used only when the second mass spectrometer is adjusted, and are used as a normal tandem mass spectrometer as a daughter ion accompanying the dissociation of the parent ion. Is not used when analyzing the mass of Therefore, if this can be omitted, the overall manufacturing cost may be reduced.

However, in the case where the daughter ion acceleration voltage and the second electric field are scanned while keeping the second magnetic field constant, and the adjustment is performed while observing the spectrum shape, the control system must be the same.

A first object of the present invention is to provide a tandem mass spectrometer that is streamlined without providing the second ion source acceleration power supply 13 and its control unit.

A second object of the present invention is to maintain the second magnetic field constant, scan the daughter ion accelerating voltage and the second electric field, and adjust the performance while watching the spectrum shape. It is an object of the present invention to provide a tandem mass spectrometer which can also be used for a mass spectrometer.

[Means for Solving the Problems] In order to achieve the first object, the present invention provides a first ion source for ionizing a sample and accelerating it by an accelerating power supply, and a first ion source for separating a specific parent ion from the ions. A mass spectrometer, a gas collision chamber for dissociating parent ions, and a second mass spectrometer for mass analyzing the dissociated daughter ions, wherein the gas collision chamber is provided with a second ion source for adjusting the performance of the second mass spectrometer. A tandem mass spectrometer provided with a switching means for applying an output of an acceleration power supply for a first ion source to a second ion source when the performance of the second mass spectrometer is adjusted. It is.

The switching means, specifically, an insulating cylinder having a predetermined insulating edge surface distance on the inner periphery, an insulating rotating body disposed in the insulating tube and having a predetermined insulating edge surface distance on the outer periphery and the corrugated recess, It is a rotary switch consisting of contacts formed on the inner and outer circumferences, for example, a rotary knob
When turned 180 degrees, an ion acceleration voltage is applied to either the first ion source or the second ion source.

In order to achieve the second object, the present invention also provides a first ion source for ionizing a sample and accelerating the sample by an accelerating power source, and a first ion source for separating a specific parent ion from the ions by a first electric field and a first magnetic field. 1) a mass spectrometer, a gas collision chamber for dissociating parent ions, and a second mass spectrometer for mass analyzing the dissociated daughter ions by a second electric field and a second magnetic field. A tandem-type mass spectrometer that includes a second ion source for adjusting the performance of the above, scans the daughter ion acceleration voltage and the second magnetic field while keeping the second magnetic field constant, and adjusts the performance according to the spectrum shape. Switching means for applying the output of the first ion source accelerating power supply to the second ion source when adjusting the performance of the analyzer; and controlling the control terminals of the second electric field power supply and the second magnetic field power supply and the output of the second mass spectrometer. 2 mass spectrometer It proposes a tandem mass spectrometer provided with a means for switching the connection from the control unit to the first mass analyzer controller having the capability adjustment function.

[Operation] In the present invention, when the performance of the second mass spectrometer is adjusted,
Since the rotary switch for applying the output of the acceleration power source for the first ion source to the second ion source is provided, the acceleration power source for the second ion source becomes unnecessary, which is advantageous in terms of space and cost.

Further, an insulating cylinder having a predetermined insulating edge surface distance on the inner periphery,
The insulating rotating body which is disposed in the insulating cylinder and has a predetermined insulating edge surface distance between the outer periphery and the corrugated recess has a sufficient withstand voltage as a high-voltage switching mechanism, and the rotating mechanism has reliability. The cost is about 1/10 of the acceleration power supply for the ion source.

Further, the accuracy of determining the mass number of the second mass spectrometer can be calibrated with the same acceleration power supply and control system, and the accuracy as a tandem mass spectrometer is improved.

Embodiment FIG. 1 is a diagram showing a system configuration of an embodiment of a tandem mass spectrometer provided with a switching means of an acceleration power supply for an ion power supply according to the present invention. Portions performing the same functions as those of the conventional example in FIG. 5 are denoted by the same reference numerals, and description thereof is omitted.

This embodiment differs from the conventional example in FIG. 5 in that a switching means 18 is added to the output side of the first ion source acceleration power supply 9 and the conventional second ion source acceleration power supply 13 is eliminated. It is.

When used as a tandem mass spectrometer, the switching means 18 is set to A, and to adjust the performance of only the second mass spectrometer, it is set to B.

In this figure, the switching means is schematically simplified, but the actual output of the ion source accelerating power supply is seven filament power terminals, two chamber terminals, two repeller terminals, two lens terminals, etc. It is necessary. Moreover, since the acceleration voltage may be applied to a voltage of 20 kV or more, a changeover switch that is normally commercially available may discharge.
Does not stand use.

FIGS. 2 and 3 show the specific structure of an example of a high withstand voltage rotary switch that can switch these many terminals simultaneously and that uses a corrugated insulating rotary member. FIG. 2 is a side sectional view, FIG. 3 (A) is a sectional view along the line III-III, and FIG. 3 (B) is a view showing an example of a rotary knob. The insulating cylinder 31 and the insulating rotating body 32 are made of ceramics or an organic fluororesin, and an output terminal C33, a switching terminal A34, a switching terminal B35, and a ground terminal 36 corresponding to the number of output codes of the accelerating power source are provided at upper and lower portions, respectively. Installed every 180 degrees. As shown in FIG. 2, the output terminal A34 is connected to the first ion source with the first ion source cord 38, and the output terminal B35
Is connected to the second ion source by a second ion source code 39.

In this switching mechanism, since the maximum ion source acceleration voltage is applied to the upper and lower parts, it is necessary to keep a sufficient distance between the inner circumference of the insulating cylinder 31 and the outer peripheral surface of the insulating rotating body. For example,
When the maximum accelerating voltage is 20 kV, an edge distance of 20 cm is required. Therefore, the inner diameter R of the insulating cylinder is from πR = 20 cm to R = 6.4 cm.
become. In order to obtain a creepage distance of 20 cm, the outer periphery of the insulating rotating body 32 needs a corrugated concave toward the center as shown in FIG. 3 (A).

The operation of the switching mechanism will be described with reference to the display of the rotation knob 42 in FIG. 3 (B). In the state shown in the figure, an acceleration voltage is applied to the first ion source IS1. Measurements with a conventional tandem mass spectrometer are performed in this mode. If you want to adjust only the second mass spectrometer, turn the rotary knob 42 clockwise 180 degrees
If IS2 is set to a position indicating acceleration ON, IS1 is grounded and acceleration voltage is applied to IS2.

As apparent from FIG. 2, the output voltage code 3
7, Since a large number of codes such as the first ion source code 38 and the second ion source code 39 are built in the insulating rotating body 32,
Knob 42 should reciprocate rather than rotate.

In the embodiment of FIG. 1, the case where the performance of the second mass spectrometer is adjusted and the output of the acceleration power source 9 of the first ion source is switched and connected to the second ion source and controlled by the first control unit 12 will be described. Was. In a specific adjustment, the second magnetic field power supply 15 is connected to the second control unit.
Scanning with signals from 16 can adjust the resolution, intensity, mass number display accuracy, etc. of the mass spectrum.

On the other hand, the performance adjustment may be performed while keeping the magnetic field constant, scanning the ion acceleration voltage and the electric field, and observing the spectrum shape. In this case, in the method of FIG. 1, since the ion acceleration voltage and the second electric field are connected to different control systems, performance adjustment cannot be performed.

In the case of such accelerated scanning, as shown in FIG.
A mechanism for switching the electric field control signal and the magnetic field control signal of the first control unit 12 to the second electric field power supply 14 and the second magnetic field power supply 15, and the input destination of the output signal of the second detector 8 from the second control unit 16 First control unit 12
And a switching mechanism.

Although these switching mechanisms seem complicated at first glance, unlike the output switching of the acceleration voltage, they switch low voltages of several tens of volts, so if noise countermeasures are taken, they are linked with a commercially available three-stage rotary switch, Switching from A to B in the figure can be performed at once.

[Effects of the Invention] The tandem mass spectrometer provided with the switching mechanism of the present invention has the following advantages.

a. Only one ion source acceleration power supply is required. In this regard the cost is about
10% reduction.

b. Since the high voltage switching means has a sufficient withstand voltage and a reliable rotating mechanism, the cost requires only about 10% of the accelerating power supply even if the cost is estimated to be large.

c. The accuracy of determining the mass number of the second mass spectrometer can be calibrated with the same acceleration power supply and control system as the first mass spectrometer, thereby improving the accuracy as a tandem mass spectrometer.

d. The second ion source acceleration power supply rack is replaced with a compact switching mechanism. Therefore, the area occupied by the device and the load can be reduced by about 10%.

[Brief description of the drawings]

FIG. 1 is a diagram showing a system configuration of an embodiment of a tandem mass spectrometer provided with a switching means for an acceleration power source for an ion power source according to the present invention, and FIGS. 2 and 3 show switching using a corrigate insulating rotating body. FIG. 4 is a diagram showing a specific structure of an example of the means, FIG. 4 is a diagram showing a system configuration of an embodiment in which the first mass spectrometer control unit is also used for adjusting the performance of the second mass spectrometer, and FIG. 5 is a conventional tandem FIG. 1 is a diagram showing a system configuration of a mass spectrometer. DESCRIPTION OF SYMBOLS 1 ... 1st ion source, 2 ... Parent ion, 3 ... 1st electric field, 4 ...
1st magnetic field, 5 ... connection part, 5A ... 1st mass spectrometer detector, 5B
... gas collision chamber, 5C ... second ion source, 6 ... second electric field, 7 ...
Second magnetic field, 8: second mass spectrometer detector, 9: acceleration power supply for first ion source, 10: first electric field power supply, 11: first magnetic field power supply,
12: first mass spectrometer control unit, 13: acceleration power supply for second ion source, 14: second electric field power supply, 15: second magnetic field power supply, 16: second mass spectrometer control unit, 17: daughter ion, 18 ... Switching means for accelerating power supply for ion power supply, 19 ... Electric field power supply switching means, 20 ... Magnetic field power supply switching means, 21 ... Output destination switching means for second mass spectrometer detector, 31 ... Insulated cylinder, 32 ... Insulated rotating body, 33 ... output terminal C, 34
... Switching terminals A, 35 ... Switching terminals B, 36 ... Grounding terminals, 37 ...
Output voltage code, 38: code for the first ion source, 39: second
Cord for ion source, 40… Ground plate, 41… Chassis plate, 42
... Rotating knob.

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Claims (3)

(57) [Claims] 1. A first ion source for ionizing a sample and accelerating by an accelerating power supply, a first mass spectrometer for separating a specific parent ion from the ion, a gas collision chamber for dissociating the parent ion, and a dissociated daughter A tandem mass spectrometer comprising a second mass spectrometer for mass spectrometric analysis of ions, wherein the gas collision chamber includes a second ion source for adjusting the performance of the second mass spectrometer; A tandem mass spectrometer characterized by comprising switching means for applying an output of the first ion source acceleration power source to the second ion source during performance adjustment. 2. The tandem mass spectrometer according to claim 1, wherein said switching means includes an insulating cylinder having a predetermined insulating edge distance on an inner periphery, and an outer cylinder and a corrugated recess disposed in said insulating cylinder. A tandem mass spectrometer comprising a rotary switch including an insulating rotary body having a predetermined insulating edge surface distance and contacts formed on the inner and outer circumferences. 3. A first ion source for ionizing a sample and accelerating by an accelerating power supply, a first mass spectrometer for separating a specific parent ion from said ions by a first electric field and a first magnetic field,
A gas collision chamber for dissociating parent ions, and a second mass spectrometer for mass-analyzing the dissociated daughter ions by a second electric field and a second magnetic field, wherein the gas collision chamber has a second mass spectrometer for adjusting the performance of the second mass spectrometer. A tandem mass spectrometer comprising an ion source, scanning the daughter ion accelerating voltage and the second electric field while keeping the second magnetic field constant, and adjusting the performance according to the spectrum shape; Switching means for applying the output of the first ion source acceleration power source to the second ion source;
Control terminals for the second electric field power supply and the second magnetic field power supply;
Means for switching and connecting the output of the mass spectrometer from the second mass spectrometer controller to the first mass spectrometer controller having the performance adjusting function.