JPH10160707A - Liquid chromatograph mass analyzing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid chromatograph mass analyzing device with an interface part in which neutral particles are removed and only ions are sent into a mass analyzing chamber in a liquid chromatograph mass analyzing device by an atmospheric pressure ionizing method. SOLUTION: This mass analyzing device comprises a pipe 32 which is provided for a partition wall 12 between an atmosphere ionizing chamber 43 and intermediate exhaust chamber 44 and connects both chambers and a gap 14 provided for a partition wall between the intermediate exhaust chamber 44 and a mass analyzing chamber 46. The pipe 32 and gap 14 are arranged coaxially in opposing locations in the intermediate exhaust chamber 44. A pipe end face in the intermediate exhaust chamber 44 is cut to form an inclined face 32a. In addition, an evacuating means 50 of the intermediate exhaust chamber is provided so that evacuation is tilted toward the side of the inclined face 32a. By these and by performing evacuation tilted toward the side of the inclined face 32a, neutral particles are diagonally moved so that only ions are electrically derived from the gap.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid chromatograph mass spectrometer (hereinafter referred to as "LC / MS"), and more particularly to an interface between a liquid chromatograph unit and a mass spectrometric unit of LC / MS.

[0002]

2. Description of the Related Art Liquid chromatograph mass spectrometer (LC)
/ MS), the components separated in the liquid chromatograph section are ionized and introduced into the mass spectrometry section. Therefore, an interface for ionizing the separated components is needed. L
In recent years, as an interface generally used for C / MS, an electrospray interface (ES
I) and atmospheric pressure chemical ionization interface (APCI)
For example, a method of performing ionization under atmospheric pressure has been used. On the other hand, mass spectrometers provided after these interfaces are generally used under high vacuum. Therefore, LC / MS by atmospheric pressure ionization method
Usually, an intermediate exhaust chamber is provided between the atmospheric pressure ionization chamber for ionizing the liquid introduced from the liquid chromatograph section at atmospheric pressure and the mass spectrometer containing the mass spectrometer. Separate evacuation systems are provided in the evacuation chamber and the subsequent high-vacuum evacuation chamber, so that a high-vacuum state is obtained in a stepwise manner from the front stage to the rear stage. FIG. 2 is a schematic configuration diagram of a conventional example of such LC / MS. In the figure, 10 is a liquid chromatograph unit, 20 is a mass analysis unit, and 30 is an interface unit. Reference numeral 31 denotes an electrospray probe of the electrospray ionization unit, which functions as a tube for introducing an ionized sample from the liquid chromatograph unit 10. 43 is an atmospheric pressure ionization chamber, 44 is an intermediate exhaust chamber roughly exhausted by an oil rotary pump (RP) 50, 45 is a second intermediate exhaust chamber provided with a lens mechanism for converging ions, 46 is a quadrupole or an analyzer. It is a mass spectrometry room with a built-in meter, and a turbo molecular pump (TMP) 51
Thus, a higher vacuum is maintained than the intermediate exhaust chamber 44. Note that the second intermediate exhaust chamber 45 and the mass spectrometry chamber 46 may share one vacuum exhaust pump. Further, the second intermediate exhaust chamber 45, the mass spectrometry chamber 46, and the partition may be integrated without being partitioned by the partition. That is, the second intermediate exhaust chamber 45 may be included in the mass spectrometry chamber 46 in terms of configuration.

A partition 12 is provided between the atmospheric pressure ionization chamber 43 and the intermediate exhaust chamber 44, and the pipes 3 are connected to each other.
Since the two chambers communicate only with each other, an independent exhaust system is provided for each chamber, so that a high vacuum state can be maintained from the front stage to the rear stage.

[0004] A heater mechanism (not shown) is attached to the pipe 32 and functions as a desolvation means for accelerating the desolvation of charged droplets generated by the electrospray probe 31. That is, the electrospray probe 31 has a thin tube through which the sample liquid sent from the liquid chromatograph unit 10 passes, and the tip on the side facing the pipe 32 has a needle shape. Nozzles. Then, a high voltage of about several KV is applied to the electrospray probe 31 from a high voltage generating circuit (not shown). With such a structure, the liquid sample sent from the liquid chromatograph unit 10 is drawn out in a spray form by a strong electric field formed near the nozzle at the tip of the needle. At this time, a part of the liquid sample is ionized. And into the pipe 32 as charged droplets. The charged droplets are heated by the heater in the pipe 32 to evaporate the solvent, collide with other particles and the like, and are further miniaturized to promote ionization.
2 and is sent to the intermediate exhaust chamber 44.

In the intermediate exhaust chamber 44, a gap 14 is formed on the wall 13 opposite to the wall 12 on which the pipe 32 is mounted, just coaxially with the pipe 32, and the particles passing through the pipe 32 travel straight as it is. Then, it is possible to pass through the gap 14 and enter the second intermediate exhaust chamber 45. Thus, the pipe 32
When the solvent passes through, desolvation and ionization are promoted, and ions are introduced into the mass spectrometry chamber 46 via the intermediate exhaust chamber 44 and the second intermediate exhaust chamber 45.

[0006]

In the above-mentioned LC / MS, since the pipe 32 and the gap 14 are coaxially arranged, of the ions passing through the pipe, ions traveling straight ahead pass through the gap as they are, and the mass spectrometry room. Get into it. However, at this time, not only the ions but also the neutral particles pass through the gap, so that these neutral particles become noise and deteriorate the measurement sensitivity. In order to reduce this noise, the axis of the pipe may be different from the axis of the gap. However, in this case, although the amount of neutral particles passing through the gap can be reduced, the amount of ions to be analyzed also decreases at the same time, and as a result, high-sensitivity analysis cannot be performed. It became.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an LC / MS capable of solving such a problem and reducing only the amount of neutral particles passing without reducing the amount of ions passing through the space. I do.

[0008]

SUMMARY OF THE INVENTION A liquid chromatograph mass spectrometer (LC / MS) according to the present invention, which has been made to solve the above-mentioned problem, converts ions generated in an atmospheric pressure ionization chamber through an intermediate exhaust chamber. In LC / MS for detection by guiding to a mass spectrometry chamber maintained in a high vacuum state, a pipe provided on a partition wall between an atmospheric ionization chamber and an intermediate exhaust chamber and communicating between the chambers; A gap provided in a partition wall between the mass spectrometer and the pipe, and the pipe and the gap are disposed coaxially and opposed to each other in the intermediate exhaust chamber, and a pipe end surface in the intermediate exhaust chamber is inclined. And an evacuation means for the intermediate evacuation chamber is provided so that the evacuation is performed on the inclined surface side.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In an LC / MS according to the present invention, an exhaust system is configured such that a pipe end face in an intermediate exhaust chamber is obliquely cut, and the cut surface side is strongly evacuated. Therefore, the particles that have flowed through the pipe flow with a slight bias toward the cut surface. At this time, since the ions are electrically attracted to the skimmer side, the ions easily travel straight, but the neutral particles are not subjected to the electric force and are biased toward the evacuation side. About, the ions proceed obliquely in the intermediate chamber, while the ions directly travel to the gap side by the electric force.

Therefore, it is possible to prevent only the ions from passing through the gap and prevent most of the neutral particles from passing through the gap.

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view of an LC / MS showing one embodiment of the present invention.

In the drawings, the same components as those in the conventional example are denoted by the same reference numerals as in FIG. 2 and their description is omitted.

As shown in the drawing, a pipe 32 to which a heater (not shown) is attached is provided on the partition wall 12 between the atmospheric pressure ionization chamber 43 and the intermediate exhaust chamber 44, and the atmospheric pressure ionization chamber 43 and the intermediate exhaust chamber are provided. 44 is communicated with this pipe 32.

The end of the pipe 32 on the side of the atmospheric pressure ionization chamber 43 faces the electrospray probe 31 as in the conventional example. On the other hand, the end of the pipe 32 on the side of the intermediate exhaust chamber 44 is cut out obliquely to form an inclined surface 32a. The inclined surface 32a is attached to the intermediate exhaust chamber 44 so as to face the exhaust port of the vacuum pump.
By doing so, the neutral particles that have passed through the pipe 32 are easily biased toward the exhaust port side. Note that a duct serving as a guide for exhaust may be provided near the inclined surface 32a to facilitate uneven exhaust. In this case, the inclined surface 32a faces the opening of the duct serving as the exhaust guide. However, a non-conductive material such as glass is used for the duct so as not to hinder the ions from being electrically attracted to the gap.

According to the LC / MS having such a configuration, the liquid sample sent from the liquid chromatograph unit 10 is:
A strong electric field formed near the nozzle at the tip of the needle of the electrospray probe 31 causes the liquid to be drawn out in a spray form. At this time, a part of the liquid sample enters the pipe 32 as ions or charged droplets. The charged droplets are heated by a heater (not shown) in the pipe 32 to evaporate the solvent, and further collide with other particles to be further miniaturized to promote ionization.
2 and is sent to the intermediate exhaust chamber 44. At this time, neutral particles are also introduced into the intermediate exhaust chamber 44 together with the ions. Here, the ions are electrically attracted to the skimmer side, so it is easy to go straight, but the neutral particles do not receive the electric force, so they move toward the vacuum exhaust port side, and as a result, The neutral particles travel obliquely in the intermediate exhaust chamber 44 and do not pass through the gap. In this way, only ions other than neutral particles pass through the gap and are sent to the mass spectrometry chamber 46, where they are separated by mass at the quadrupole and detected by a detector (not shown).
In the present embodiment, in addition to the mass spectrometry chamber 46, a second intermediate exhaust chamber 45
However, as a matter of course, the second intermediate exhaust chamber 45 and the mass analysis chamber 46 may be provided as one. That is, when the second intermediate exhaust chamber 45 and the mass spectrometry chamber 46 are provided, the second intermediate exhaust chamber 45 and the mass spectrometry chamber 46 together constitute a mass spectrometry chamber according to the present invention.

[0016]

As described above, as described above, the LC / M according to the present invention is used.
In S, the pipe end face on the intermediate exhaust chamber side is inclined, and the vacuum exhaust is performed on the inclined surface side, so that neutral particles that are not electrically drawn in the intermediate exhaust chamber do not pass through the gap, Only ions can pass through the gap, and noise due to the presence of neutral particles can be significantly reduced. In particular, it is only necessary to use a pipe cut so as to be inclined and turn this inclined surface toward the vacuum exhaust side, so that neutral particles can be removed with a simple configuration, so work such as pipe alignment can also be performed It becomes easy, and adjustment of the device can be easily performed.

[Brief description of the drawings]

FIG. 1 is a sectional configuration view of a liquid chromatograph mass spectrometer according to one embodiment of the present invention.

FIG. 2 is a cross-sectional configuration diagram of a conventional liquid chromatograph mass spectrometer.

[Explanation of symbols]

 10: Liquid chromatograph section 12, 13: Partition wall 20: Mass spectrometry section 30: Interface section 31: Electrospray probe 32: Pipe 32a: Inclined surface 43: Atmospheric pressure ionization chamber 44: Intermediate exhaust chamber 45: Second intermediate exhaust chamber 46: Mass spectrometry room 50: Rotary pump

Claims (1)

[Claims] 1. An ion generated in an atmospheric pressure ionization chamber,
In a liquid chromatograph mass spectrometer that detects and leads to a mass spectrometry chamber maintained in a high vacuum state through an intermediate exhaust chamber, the liquid chromatograph mass spectrometer is provided on a partition wall between the atmospheric pressure ionization chamber and the intermediate exhaust chamber, and is provided between the chambers. And a gap provided in a partition wall between the intermediate exhaust chamber and the mass spectrometry chamber, wherein the pipe and the gap are coaxially arranged facing each other in the intermediate exhaust chamber. In addition, the end face of the pipe in the intermediate exhaust chamber is cut out so as to be inclined, and a vacuum exhaust means of the intermediate exhaust chamber is provided so that the vacuum exhaust is performed on the inclined surface side. Liquid chromatograph mass spectrometer.