JP3909395B2 - Liquid chromatograph mass spectrometer - Google Patents

Description

[0001]
BACKGROUND 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 part and a mass spectrometer part of an LC / MS using an atmospheric pressure ionization method.
[0002]
[Prior art]
In the liquid chromatograph mass spectrometer (LC / MS), the components separated in the liquid chromatograph part are ionized and introduced into the mass spectrometer part. Therefore, there is a need for an interface that ionizes the separated components. As an interface generally used for LC / MS, a method of performing ionization under atmospheric pressure such as an electrospray interface (ESI) or an atmospheric pressure chemical ionization interface (APCI) has recently been used. On the other hand, mass spectrometers provided at the subsequent stage of these interfaces are generally used under high vacuum conditions. Therefore, LC / MS based on the atmospheric pressure ionization method is usually arranged between an atmospheric pressure ionization chamber for ionizing a liquid introduced from the liquid chromatograph section under atmospheric pressure and a mass spectrometry chamber containing a mass spectrometer. An intermediate exhaust chamber is provided, and a vacuum exhaust system is provided in the intermediate exhaust chamber and the subsequent high vacuum exhaust chamber so that the vacuum state is gradually increased from the front side to the rear side. FIG. 1 shows a schematic configuration diagram of such a conventional LC / MS example. In the figure, 10 is a liquid chromatograph section, 20 is a mass analysis section, and 30 is an interface section. Reference numeral 31 denotes a spray probe (electrospray probe or the like) of the ionization unit, which functions as an ionized sample introduction tube from the liquid chromatograph unit 10. 43 is an atmospheric pressure ionization chamber, 44 is an intermediate exhaust chamber that is roughly evacuated by an oil rotary pump (RP), 45 is a second intermediate exhaust chamber having a lens system for converging ions, 46 is a quadrupole rod or detection The mass spectrometric chamber has a built-in chamber, and is maintained at a higher vacuum than the intermediate exhaust chamber 44 by a turbo molecular pump (TMP).
[0003]
The atmospheric pressure ionization chamber 43 and the intermediate exhaust chamber 44 are partitioned by a partition wall 12 and a solvent removal unit 13 is provided. The solvent removal unit 13 includes a heating block 32 including a heater (not shown) and a pipe 33 that passes through the heating block 32. The atmospheric pressure ionization chamber 43 and the intermediate exhaust chamber 44 are configured to communicate with each other only through the pipe 33. ing. Therefore, when the intermediate exhaust chamber 44 is evacuated by the oil rotary pump (RP), part of the gas in the atmospheric pressure ionization chamber 43 flows in through the pipe 33.
[0004]
The pipe 33 is heated by the heating block 32 and functions as a desolvation unit for promoting desolvation of the charged droplet generated by the spray probe 31. That is, a part of the charged droplet sprayed from the spray probe 31 flows into the pipe 33 due to the differential pressure between the atmospheric pressure ionization chamber 43 and the intermediate exhaust chamber 44 and is heated in the pipe 33, thereby removing the solvent. Is introduced into the intermediate exhaust chamber 44 while being promoted.
[0005]
The ions introduced into the intermediate exhaust chamber 44 are introduced into the second intermediate exhaust chamber 45 and the mass analysis chamber 46 that have been exhausted to a higher vacuum and are detected by the detector.
[0006]
In such an LC / MS, in order to introduce charged droplets sprayed from the spray probe as many ions as possible into the intermediate exhaust chamber, a pipe which is an ion passage between the atmospheric pressure ionization chamber and the intermediate exhaust chamber The tip of 33 on the atmospheric pressure ionization chamber side is located in the spray spray area in front of the spray probe. However, if the charged droplet sprayed from the spray probe goes straight and passes through the pipe as it is, problems such as an increase in noise occur. Therefore, bending the pipe prevents the straight component from passing through the pipe as it is. Try to reduce the noise.
[0007]
[Problems to be solved by the invention]
However, although the introduction of charged droplets that go straight by bending the pipe into the intermediate exhaust chamber can be removed, the pipe tip is eventually contaminated with the sprayed sample and solvent when used continuously. It causes phenomena such as increased noise, reduced sensitivity, and clogging of pipes. Therefore, if a phenomenon such as an increase in noise becomes frequent, it is necessary to replace the pipe and clean it. At that time, in order to replace the pipe in the conventional apparatus, the apparatus is stopped, the vacuum exhaust after the intermediate exhaust chamber is stopped, and after returning to atmospheric pressure, the heating block is removed.
[0008]
Therefore, the present invention eliminates the harmful effects of breaking the vacuum by allowing the tip of the pipe to be replaced while maintaining the vacuum after the intermediate exhaust chamber without stopping the vacuum exhaust. The purpose is to provide MS.
[0009]
[Means for Solving the Problems]
The liquid chromatograph mass spectrometer (LC / MS) of the present invention made to solve the above problem is an intermediate exhaust in which ions generated by ionization means are maintained in a vacuum state through a pipe in an atmospheric pressure chamber. In the liquid chromatograph mass spectrometer, which is led to a chamber and further to a detector in the mass spectrometry chamber adjacent to the intermediate exhaust chamber for detection, the pipe is entirely in the atmospheric pressure chamber and the outlet end is in the middle is divided into a outlet pipe connected to the exhaust chamber, they together are connected together at atmospheric pressure chamber, characterized in that the detachable said inlet-side pipe.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
In the LC / MS of the present invention, the pipe communicating between the atmospheric pressure chamber and the vacuum intermediate exhaust chamber is divided into an inlet side pipe that is entirely in the atmospheric pressure chamber and an intermediate exhaust chamber that is in the vacuum state at the outlet end. And an outlet pipe connected thereto. The inlet side pipe and the outlet side pipe are connected so as to be integrated with each other at a connecting portion in the atmosphere chamber. Therefore, it is possible to replace only the easily contaminated inlet side pipe, and the inlet side pipe can be replaced only in the atmospheric pressure chamber, so that the vacuum in the intermediate exhaust chamber and the mass spectrometry chamber was maintained during the replacement operation. Can be done as is.
[0011]
Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 is an LC / MS cross-sectional view showing an embodiment of the present invention, and FIG. 3 is an enlarged view of a main part thereof. The parts not particularly shown in the LC / MS of the present invention are the same as those of the conventional example of FIG. 1, and therefore, the description thereof will be omitted by attaching the same reference numerals.
[0012]
As shown in the drawing, a heating block 32 is attached to the partition wall 12 between the atmospheric pressure ionization chamber 43 and the intermediate exhaust chamber 44, and an outlet side pipe 33b is attached so as to pass through the heating block 32. The outlet pipe 33b is heated by heating the heater built in the heating block 32. On the other hand, in addition to the outlet side pipe 33b, the atmospheric pressure ionization chamber 43 has an inlet side pipe 33a and a connecting member 34 made of a metal block or the like. The inlet side pipe 33a and the outlet side pipe 33b are respectively connected members. 34 is connected to a through hole 35 provided in 34 via ferrules 36 and 37. Therefore, the inlet side pipe 33a, the through hole 35, and the outlet side pipe 33b form a flow path that communicates from the atmospheric pressure ionization chamber 43 to the intermediate exhaust chamber 44. The connection between the pipe 33a and the connection member 34 is not necessarily performed by the ferrule 36. In short, any connection method that allows the pipe 33a to be easily detached and has a good sealing property is sufficient.
[0013]
With this configuration, when charged droplets are sprayed from the electrospray 31, a part of the droplets is sucked from the inlet side pipe 33a and introduced into the intermediate exhaust chamber while desolvation is promoted by heating. The Some of the droplets adhere to the inner wall of the pipe and become dirty. Therefore, after use for a certain period, pipe cleaning or pipe replacement work for removing dirt is required. At this time, the pipe is replaced by removing the inlet side pipe 33a from the connecting member 34. At this time, since the outlet side pipe 33b remains attached, the replacement work can be performed while maintaining the vacuum state of the intermediate exhaust chamber 44.
[0014]
In this embodiment, the outlet side pipe 33b is attached to the partition wall 12 via the heating block 32. However, as shown in FIG. 4, the outlet side pipe 33b is attached using bolt nuts 38 and 39 for fastening a general partition wall. You may connect. In this case, the pipe is heated by providing a heater in the connection member 34. Alternatively, a heater may be wound directly around the outlet side pipe 33b.
[0015]
【The invention's effect】
As described above, in the LC / MS of the present invention, the pipe for guiding the ions generated in the atmospheric pressure chamber to the intermediate exhaust chamber maintained in a vacuum state is divided, and the pipe is connected by the connecting member in the atmospheric chamber. Since it is possible to replace only the inlet side pipe in the atmospheric chamber, it is not necessary to stop the vacuum exhaust of the intermediate exhaust chamber during the pipe replacement work for cleaning, Pipe cleaning can be performed without exposing the intermediate exhaust chamber and the subsequent air to the atmosphere. Further, since only the heavily contaminated inlet side pipe portion can be removed and cleaned, it can be easily cleaned by, for example, ultrasonic cleaning.
[Brief description of the drawings]
FIG. 1 is a cross-sectional configuration diagram of a conventional liquid chromatograph mass spectrometer.
FIG. 2 is a cross-sectional configuration diagram of a liquid chromatograph mass spectrometer which is an embodiment of the present invention.
FIG. 3 is an enlarged view of a desolvent part in FIG. 2;
FIG. 4 is an enlarged view of a desolvation part according to another embodiment of the present invention.
[Explanation of symbols]
10: liquid chromatograph unit 12: partition wall 13: solvent removal unit 20: mass analysis unit 30: interface unit 31: electrospray probe 32: heating block 33a: inlet side pipe 33b: outlet side pipe 34: connecting member 35: through hole 36, 37: Ferrule 43: Atmospheric pressure ionization chamber 44: Intermediate exhaust chamber 46: Mass spectrometry chamber

Claims (1)

A liquid chromatograph in which ions generated by ionization means in the atmospheric pressure chamber are led to an intermediate exhaust chamber maintained in a vacuum state via a pipe, and further introduced to a detector in the mass spectrometry chamber adjacent to the intermediate exhaust chamber. In the mass spectrometer, the pipe is divided into an inlet side pipe whose whole is in the atmospheric pressure chamber and an outlet side pipe whose outlet end is connected to the intermediate exhaust chamber, and these pipes are integrally connected in the atmospheric pressure chamber. Rutotomoni, liquid chromatograph mass spectrometer, characterized in that the detachable said inlet-side pipe.

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