JPH0577143B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a gas chromatograph mass spectrometer that combines a gas chromatograph and a quadrupole mass spectrometer.

<Prior Art> A conventional interface section of this type of gas chromatograph mass spectrometer has a configuration shown in FIG.

In the figure, reference numeral 1 is a housing for configuring a vacuum chamber, and 2 is an interface block. It is fixed to the heat insulating wall 6 that constitutes the room.
Further, 8 is a column for separating the components of a gas sample, and is inserted into a column insertion hole 2a formed in the center of the interface blot 2 described above.
10 is a ferrule, 12 is a washer, and 14 is a cap nut. These 10, 12, and 14 fix the column 8 and hermetically seal the space between the housing 1 and the oven chamber. 16 is a heater, and 18 is a temperature measuring element for controlling the heater 16. Both 16 and 18 are inserted into the interface block 2, whereby the column 8 is indirectly heated and the gas is heated. This is intended to prevent the adsorption of Reference numeral 20 denotes an ionization chamber for ionizing the gas whose components have been separated from the column 8. An insulating bush 22, a pressing tool 24, and a spring 26 are interposed between the ionization chamber 20 and the interface block 2. As a result, the ionization chamber 20 and the interface block 2 are electrically insulated while maintaining a degree of freedom in determining the distance between them. 28 and 30 are a heater and a temperature measuring element inserted into the ionization chamber 20, and 32 is an ion exit port. Further, 34 is a filament for generating thermionic electrons, 36 is a trap for receiving thermionic electrons, and 38a and 38b are provided to make the thermionic electrons from the filament 34 cause a spiral motion to increase the probability of collision with the gas. It is a collimation magnet.

<Problems to be Solved by the Invention> By the way, as shown in FIG. Apply a positive voltage to
Moreover, the ionization chamber 20 is electrically insulated from the interface block 2 by interposing an insulating bush 22, a pressing member 24, and a spring 26 between the ionization chamber 20 and the interface block 2.

However, such a conventional structure requires the insulating bush 22, the pressing tool 24, and the spring 26, so the overall structure of the interface part is complicated, and the column 8
A long one is also required. Therefore, maintenance such as cleaning when the interface portion becomes dirty becomes troublesome. Further, since the ionization chamber 20 and the interface block 2 are thermally insulated, the ionization chamber 20 and the interface block 2 require separate heaters 28 and 16, respectively. Furthermore, since thermal insulation between the ionization chamber 20 and the interface block 2 is unavoidable, the heat distribution becomes non-uniform and there is a risk of gas adsorption within the column 8 located between them.

<Means for Solving the Problems> The present invention has been made in view of the above circumstances, and is designed to improve the structure of the interface portion that connects the gas chromatograph and the quadrupole mass spectrometer compared to the conventional one. By simplifying the structure, the distance to the ionization chamber can be shortened, thermal uniformity can be ensured, and maintenance in case of contamination can be easily performed.

Therefore, the present invention provides a gas chromatograph equipped with a gas chromatograph that separates each component in a gas sample, a quadrupole mass spectrometer that separates each component by mass, and an interface disposed between the two. The mass spectrometer has the following configuration.

That is, in the present invention, an ionization chamber of a quadrupole mass spectrometer and an interface block into which a column is inserted are integrally formed to constitute an interface block with an ionization chamber. While the ground potential is set, a predetermined negative bias voltage is applied to the quadrupole electrodes of the quadrupole mass spectrometer.

<Function> In the above configuration, since the ionization chamber and the interface block constituting the interface block with ionization chamber are integrally formed, their heating can be controlled by a pair of heaters and a temperature measuring element. Moreover, uniform heating can be obtained. In addition, for conservative purposes, only the interface block with ionization chamber can be removed from the housing for easy cleaning. Furthermore, while the interface block with the ionization chamber is set to ground potential, a predetermined negative bias voltage is applied to the quadrupole electrodes of the quadrupole mass spectrometer.
A potential gradient is formed between the ionization chamber 0 and the quadrupole electrode 40, so that the ions generated in the ionization chamber are efficiently drawn toward the quadrupole mass spectrometer.

<Example> FIG. 1 is a front sectional view of the interface part of a gas chromatograph mass spectrometer according to an example of the present invention, and parts corresponding to the conventional example shown in FIG. 3 are designated by the same reference numerals. attach

In Fig. 1, numeral 1 is the housing, 4 is O
Ring, 6 is a heat insulating wall, 8 is a column, 10 is a ferrule, 12 is a washer, 14 is a cap nut, 16 is a heater, 18 is a temperature measuring element, 32 is an ion exit port, 34 is a filament, 36 is a trap, 38
a and 38b are collimation magnets,
These configurations are the same as those of the conventional example, so their explanation will be omitted.

A feature of the present invention is that the ionization chamber 3a and the interface block 3b are integrally formed to form an interface block 3 with an ionization chamber.
is configured. That is, this interface block 3 with ionization chamber
An ionization chamber 3a is integrally extended from an interface block 3b to which one end of the housing 1 is fixed via an O-ring 4, and the center of the interface block 3b communicates with the inside of the ionization chamber 3a. A column insertion hole 3c is formed, and a column is inserted into this column insertion hole 3c. Furthermore, a heater 16 and a temperature measuring element 18 are arranged above and below the column insertion hole 3c. Further, in this embodiment, as shown in FIG. 2, the above-mentioned interface block 3 with an ionization chamber is set to the ground potential, while the quadrupole electrode 40 of the quadrupole mass spectrometer has a predetermined voltage. A negative bias voltage (-U') is applied.

In the above configuration, since the ionization chamber 3a and the interface block 3b that constitute the interface block 3 with an ionization chamber are integrally formed, the heating control is performed using a pair of heaters 16 and a temperature measuring element. 1
8, and moreover, uniform heating can be obtained. Furthermore, for maintenance purposes, only the interface block 3 with ionization chamber can be removed from the housing 1 and easily cleaned. Furthermore, while the interface block 3 with ionization chamber is set to ground potential, a predetermined negative bias voltage (-U') is applied to the quadrupole electrode 40 of the quadrupole mass spectrometer. ,
A potential gradient is formed between the ionization chamber 3a and the quadrupole electrode 40, so that the ions generated in the ionization chamber 3a, as in the conventional case,
It is efficiently drawn toward the quadrupole mass spectrometer 40.

<Effects of the Invention> According to the present invention, the structure of the interface portion that connects the gas chromatograph and the quadrupole mass spectrometer is simpler than before without sacrificing necessary characteristics, so that even the ionization chamber can be easily Excellent effects such as short distances, thermal uniformity, and ease of maintenance in the event of contamination are achieved.

[Brief explanation of the drawing]

1 and 2 illustrate an embodiment of the present invention.
Figures 4 and 4 show conventional examples, respectively.
Figure 1 is a front sectional view of the interface part of the gas chromatograph mass spectrometer, Figure 2 is an explanatory diagram showing the relationship between the set potentials of the ionization chamber and the quadrupole mass spectrometer, and Figure 3 is the gas chromatograph mass spectrometer. FIG. 4 is a front cross-sectional view of the interface portion of the analyzer, and is an explanatory diagram showing the relationship between the set potentials of the ionization chamber and the quadrupole electrodes of the quadrupole mass spectrometer. 1...Housing, 3...Interface block with ionization chamber, 3a...Ionization chamber, 3b...Interface block,
8... Column, 40... Quadrupole mass spectrometer.

Claims (1)

[Scope of Claims] 1. A gas chromatograph that includes a gas chromatograph that separates each component in a gas sample, a quadrupole mass spectrometer that separates each component by mass, and an interface that is disposed between the two. In the quadrupole mass spectrometer, the ionization chamber of the quadrupole mass spectrometer and the interface block into which the column is inserted are integrally formed to constitute an interface block with an ionization chamber, and this interface with the ionization chamber A gas chromatograph mass spectrometer, characterized in that the block is set to a ground potential, while a predetermined negative bias voltage is applied to the quadrupole electrodes of the quadrupole mass spectrometer.