JPH08329884A - MS / MS type quadrupole mass spectrometer - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide an MS / MS quadrupole mass spectrometer that is easy to assemble and that always guarantees high sensitivity characteristics. [Structure] An insulator such as glass, which has a star-shaped cross-section with four rays, has a cylindrical substrate 11 having a hyperbolic surface on its inner surface, and forms a thin film electrode on the surface of the hyperbolic surface. 12a to 12d are coated. Then, the thin film electrode 12a is formed by the two partitions 15a and 15b inserted in the base 11.
Separate ~ 12d to form a triple quadrupole.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an MS / MS type quadrupole mass spectrometer.

[0002]

2. Description of the Related Art A conventional MS / MS type quadrupole mass spectrometer, as shown in FIG. 3, includes three sets of four quadrupoles each including four rod electrodes, which are provided between an ion source 31 and a detector 33. It is arranged coaxially. All of them are arranged in a high vacuum chamber, a case 32 having an opening only at an ion passage point is provided around the central quadrupole Q2, and a cleavage gas is introduced into the inside. In the quadrupole Q1 closer to the ion source 31, the target parent ion is selected from the incident ions including various ions, and in the intermediate quadrupole Q2, the parent ion is cleaved into daughter ions by collision with the cleavage gas, At the quadrupole Q3 closer to the detector 33, each daughter ion is identified by mass scanning. Note that placing the five sets of quadrupole Q1~Q5 coaxially and MS / MS / MS to perform the cleavage twice, but is also considered MS ^n, etc. for performing more times the cleavage, in this application The “MS / MS” used refers to those including these.

[0003]

Even for the target ions, only the ions that can pass through the quadrupole are incident on a very limited region near the central axis. Therefore,
In the MS / MS quadrupole mass spectrometer, if the quadrupoles are not correctly arranged coaxially, the sensitivity will be significantly reduced.

In the conventional MS / MS quadrupole mass spectrometer, a plurality of quadrupoles are correctly arranged coaxially at the time of manufacture, and in order to prevent the quadrupoles from being confused during use, FIG.
As shown in (a), each quadrupole Q1 to Q3 fixed by the ceramic holder 41 is placed on one solid surface plate 42, or as shown in FIG. Shaped pipe 43
It was inserted and fixed inside. However, with the method of fixing the quadrupoles Q1 to Q3 on the one surface plate 42, it is difficult to arrange the plurality of quadrupoles Q1 to Q3 correctly and coaxially at the beginning (that is, at the time of manufacturing). In addition, even during use, there is a possibility that the initial correct arrangement may be displaced due to uneven heat generation. In the method of inserting into the pipe 43, since the total length of the pipe 43 is long, when a heavy quadrupole is inserted, it is slightly bent (deflection) as described later.
Occurs and the sensitivity decreases.

Further, in the conventional quadrupole, each rod is made of a bulk metal rod, so that the total weight becomes very large especially when the number of quadrupoles is large like MS / MS. Was becoming. For this reason, it is inconvenient to handle during manufacture and use, and there is also an essential problem as an analyzer that the sensitivity is lowered due to the above-mentioned deflection.

Further, the curved surface on the central axis side of each rod of the quadrupole is theoretically a hyperbolic surface (a surface formed by a hyperbola moving in parallel to a plane to which it belongs).
However, it is difficult to process a metal rod into such a special shape, and it is also necessary to arrange all four rods so that their vertices correctly face the central axis of the quadrupole. Have difficulty. For this reason, conventionally, a simple cylindrical shape is often substituted, and the sensitivity is sacrificed.

The present invention has been made in order to solve these problems, and an object of the present invention is to make it easy to assemble and to ensure high sensitivity characteristics at all times.
An object is to provide an S / MS type quadrupole mass spectrometer.

[0008]

The MS / MS type quadrupole mass spectrometer according to the present invention made to solve the above-mentioned problems is characterized by including the following respective elements. a) Substrate: A cylindrical member made of an insulator. The cutting line of the inner surface formed by cutting the surface perpendicular to the central axis includes four curved lines which are convex toward the central axis.
Then, these four curves are located at positions symmetrical about the central axis. Therefore, on the inner surface of the base body, there are four curved surfaces (hereinafter, referred to as electric field forming surfaces) that are convex toward the central axis formed by the parallel movement of these four curves in the central axis direction. It will be. b) Four-sided thin film electrodes: thin film electrodes formed on the inner surface of the substrate. Each of these is at least a ridge line which is a set of points closest to the central axis of the curve (= the ridge line formed by moving the point closest to the central axis of the curve parallel to the central axis = the electric field forming surface). It is formed so as to cover the vicinity of the ridgeline on the central axis side. And these 4
The faces are separated from each other except at the ridge. c) At least two partition walls: These are inserted so as to cut the inner surface of the base body at least at two places in the middle portion of the base body, perpendicular to the central axis. An ion passage hole is provided at the center of each partition.

[0009]

The four thin-film electrodes form four independent electrodes on the inner surface of the base material (hereinafter referred to as inner surface electrodes). The above-mentioned at least two partition walls form four inner surfaces. Each of the electrodes is divided into three or more pieces in the longitudinal direction. The shape of the electric field forming surface is the same as the surface on the central axis side of the rod of the conventional MS / MS quadrupole mass spectrometer (hyperbolic surface or cylindrical surface).
Therefore, these inner electrodes electrically perform exactly the same action as the conventional quadrupole rod.

When two partition walls are inserted in two places of the base body, the inner surface of the base body is completely divided into three places in the longitudinal direction,
The middle part can be used as a cleavage chamber.

As described above, the MS / MS type quadrupole mass spectrometer according to the present invention can perform exactly the same function as the conventional MS / MS type quadrupole mass spectrometer.

[0012]

In the MS / MS type quadrupole mass spectrometer according to the present invention, the substrate can be made of quartz, glass, ceramic or the like, and its electric field forming surface can be formed into a free shape. Therefore, an ideal hyperbolic surface can be formed at low cost without compromising the difficulty of processing as in the conventional MS / MS quadrupole mass spectrometer. Moreover, since the three-stage quadrupole of Q1, Q2, and Q3 is integrally formed from the beginning by one base,
No deviation occurs during assembly or use unlike the conventional separation type. As a result, the MS / MS type quadrupole mass spectrometer according to the present invention can always perform highly sensitive analysis.

Next, since the electrode is formed of a thin film on the inner surface of the substrate, the electrode can be made much lighter than the conventional one without using a conventional bulky metal rod. This facilitates handling during manufacture and use, and eliminates sensitivity deteriorating factors such as bending due to its own weight.

[0014]

EXAMPLE An MS / MS type quadrupole mass spectrometer which is one example of the present invention will be described with reference to FIGS. 1 and 2. As shown in FIG. 1, the three sets of quadrupoles, which are the center of the MS / MS quadrupole mass spectrometer of the present embodiment, have a star-shaped cross-section as shown in FIG. The substrate 11 is shaped like a circle. Four inwardly convex hyperbolic surfaces are formed on the inner surface of the substrate 11 so as to be axially symmetrical with respect to the central axis thereof, and the surfaces of each hyperbolic surface are covered with the thin film electrodes 12a to 12d. These thin film electrodes 12a to 12d are separated by grooves 13a to 13d which are convex portions on the outer surface of the inner surface of the base body 11, whereby the four thin film electrodes 12a to 12d are separated.
Are electrically independent of each other.

Such a substrate 11 can be manufactured by, for example, a vacuum forming method of glass. In addition to glass, quartz, ceramics, hard plastic, or the like can be used. The thin film electrodes 12a to 12d are well-known C
It can be formed by a method such as VD, PVD, or electroless plating. At that time, regarding the portions of the grooves 13a to 13d,
By masking before the thin film electrode forming step, the thin film electrodes 12a to 12d are separated.
The substantially central portion of the base 11 (both slits 14a, which will be described later,
A gas introduction port 17 is provided in any one groove portion (groove 13a in FIG. 1) between 14b).

A partition wall 15a is provided on one side surface of the base 11 at two positions where the base 11 is divided into three substantially equal parts.
Slits 14a and 14b for inserting 15b are provided. The slits 14a and 14b are formed on the inner surface of the base 11,
It is formed in such a size that it can be cut almost all around it. Therefore, as shown in FIG. 2 (a), by inserting the partition walls 15a and 15b of the insulator into the slits 14a and 14b so as to be as close to the center as possible,
A space surrounded by the base 11 and the partitions 15a and 15b is formed in the center. In addition, the partition wall 15 of this insulator
Since the electric field forming surface on the inner surface of the substrate 11 is entirely cut by a and 15b, each of the four thin film electrodes 12a to 12d is also cut at two locations by the partition walls 15a and 15b and separated into three pieces in the longitudinal direction. Thin film electrode. A voltage can be applied to each of the thin film electrodes thus separated from the outside through thin film conducting paths formed so as to pass through both ends of the base 11 or the slits 14a and 14b. As a result, the first-stage quadrupole Q1, the second-stage quadrupole Q2, and the third-stage quadrupole Q3 are formed on the inner surface of the base 11.

A metal plate is embedded approximately in the center of the partition walls 15a and 15b, and an ion passage hole is provided in the center thereof. This is to prevent charge-up due to collision of ions and to apply a voltage for ion focusing. The metal plate having the ion passing holes is embedded inside the partition walls 15a and 15b (or provided on the outer surface of the partition walls 15a and 15b = the surface on the side not contacting the thin film electrodes 12a to 12d) to the outside through a lead wire. Keep it conductive. The partition wall 1
5a, 15b and the ion passage hole are all made of an insulator,
A metal thin film may be coated only on the periphery of the passage hole so that the coated portion is also electrically connected to the outside.

FIG. 2 shows the base body 11 thus constructed.
As shown in (a), it is sandwiched from both sides by holders 23a and 23b, and an ion source 21, an ion lens 22, a deflector 24, an ion detector 25, and the like similar to those of the conventional apparatus are provided before and after the holder 23a and 23b. The MS / MS quadrupole mass spectrometer is completed.

When this MS / MS quadrupole mass spectrometer is used, R is applied to each of the thin film electrodes 12a to 12d constituting the quadrupoles Q1 to Q3 of the first to third stages, just like the conventional device.
By applying and scanning the F / DC voltage, mass spectrometry can be performed in exactly the same manner as the conventional device.

In the MS / MS quadrupole mass spectrometer according to this embodiment, the electrode shape can be easily and inexpensively formed into an ideal hyperbolic surface, so that a highly sensitive analyzer can be realized at low cost. can do. Further, since the positional deviation of the quadrupoles Q1 to Q3 of the first to third stages hardly occurs during manufacturing and use, an ideal electrode arrangement (alignment)
Is guaranteed, and analysis can always be performed with high sensitivity.

Although the inner surface is a hyperbolic surface in the above embodiment, it may of course be a cylindrical surface. Further, the number of partition walls can be set to 4 to form an MS / MS / MS quadrupole mass spectrometer, or more partition walls can be inserted to construct an MS ⁿ quadrupole mass spectrometer. Is possible. For the above reason, the MS / MS quadrupole mass spectrometer according to the present invention is more advantageous in sensitivity and handling than the conventional device as the number of quadrupoles is increased.

The quadrupoles Q1 and Q2 of the first and second stages
By separating the thin-film electrodes 12a to 12d in the front or rear part from each other by a line in the circumferential direction, it is possible to realize a function equivalent to that of the pre- or post-rod attached to the quadrupole.

[Brief description of drawings]

FIG. 1 is a perspective view of a substrate used in an MS / MS quadrupole mass spectrometer which is an embodiment of the present invention.

FIG. 2 is a side view (a) of the MS / MS quadrupole mass spectrometer of the embodiment and a cross-sectional view (b) taken along line bb thereof.

FIG. 3 is an explanatory diagram showing the operating principle of an MS / MS quadrupole mass spectrometer.

FIG. 4 is an explanatory diagram showing a method for aligning the arrangement of three quadrupoles in a conventional MS / MS quadrupole mass spectrometer.

[Explanation of symbols]

 11 ... Substrate 12a-12d ... Thin film electrode 13a-13d ... Groove 14a, 14b ... Slit 15a, 15b ... Partition wall 17 ... Gas inlet 21 ... Ion source 22 ... Ion lens 23a, 23b ... Holder 24 ... Deflector 25 ... Ion detector

Claims (1)

[Claims] 1. A cylindrical member comprising a) an insulator,
A base body, in which the cutting line on the inner surface when cut along a plane perpendicular to the central axis includes four curves which are axially symmetric with respect to the central axis and which are convex toward the central axis side; C) at least the four-sided thin-film electrodes that are formed on the inner surface at least near the ridgeline that is the set of points closest to the center axis of the curve and are separated from each other at the portions other than the ridgeline; An MS / MS quadrupole mass spectrometer characterized by comprising: a partition wall which is inserted so as to cut the inner surface of the substrate perpendicularly to the central axis at two locations and which has an ion passage hole at the center thereof; .