JPH02184751A - Interface of supercritical fluid chromatograph/mass spectrograph - Google Patents

Abstract

PURPOSE:To execute the ionization of the elution component separated from supercritical fluid chromatograph (SFC) by an arbitrary ionization system by providing an ion source and belt as well as the SFC. CONSTITUTION:The elution component deposited in the end part 7a of a pipe 7 is blown out downward as a moving phase is ejected; therefore, the component sticks onto the belt 15. Since the belt 15 is transferred to an ion source 10 side at a specified speed according to the rotation of a pinch roller 21, the elution component separated by the SFC 1 is developed as chromatogram on the belt 15. This component is enclosed by the auxiliary belt 23 in the position of a guide roller 24 and is thereafter introduced through sealing means 18a to 18c into an ion source 19. The belt 23 is forcibly stripped by pulleys 25a, 25b and only the component sticking to the belt 15 is transferred to an ionization section 29 where the component is irradiated with a primary particle beam B and is ionized. The formed ions I are drawn out by an electrode group 10 and is accelerated and focused. The focused ion is introduced into a mass analysis system and is subjected to a mass analysis.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a supercritical fluid chromatograph/mass spectrometer, and particularly to improvements in an interface for connecting both devices.

[Prior art] Supercritical fluid chromatography (hereinafter referred to as SFC), which uses a supercritical fluid with intermediate properties between gas and liquid as a mobile phase, has higher separation power and shorter analysis time than high-performance liquid chromatography. It has the characteristic of being short. Also,
Compared to gas chromatography, it is possible to analyze even volatile components and thermally unstable chemical species, making it an effective means of separation. On the other hand, a so-called SFC/MS, which is a device in which eluted components separated by SFC are introduced into a mass spectrometer (hereinafter referred to as MS) and analyzed in an online manner, is being developed.

FIG. 5 is a schematic configuration diagram showing a conventional example of such SFC/MS, in which 1 is an SFC, a gas cylinder 2 filled with CO2 gas (carbon dioxide), a liquid sending pump 3 with a cooler, an injector 4, and a microcolumn 5. It consists of an oven 6 for keeping this column at a constant temperature. In SFC, first, the CO□ gas in the gas cylinder 2 is once liquefied by the liquid transfer pump 3 with a refrigerator. This liquefaction is performed in order to introduce a small amount of CO2 gas as a mobile phase into the microcolumn 5 at a constant flow rate. And the liquefied CO□ is COz
CO2 is introduced into the microcolumn 5 kept at a temperature above the critical point of CO2 (31°C or above) by an oven 6 at a pressure above the critical point of CO2 (73 atm or above).
A supercritical fluid mobile phase of □ is formed. In this state, when a sample is injected from the injector 4, the sample is dissolved in the supercritical fluid and expanded and separated in the column. The separated eluted components (sample components) are introduced into the ion source of the MS 8 through the tube 7, ionized by electron impact, etc., and subjected to mass spectrometry.

Note that when the mobile phase in SFC is a liquid at room temperature, for example, an organic solvent such as hexane, there is no need for liquefaction, so there is no need to equip the liquid pump 3 with a refrigerator. Furthermore, in SFC, in order to maintain the pressure within the flow system at a pressure higher than the supercritical point, it is necessary to provide resistance at the outlet portion of the mobile phase, that is, at the open end of the tube 7. To this end, it is possible to use a capillary tube with a very small inner diameter as the tube 7, or to fill the open end of the tube 7 with a filter (porous member) made by sintering powder such as stainless steel. By installing an orifice at the tip of tube 7, the resistance at the open end of tube 7 is increased. Further, since the pressure of the supercritical fluid mobile phase discharged from the tube 7 is reduced and gasified, the eluted components (if solid at room temperature) are precipitated as powder.

On the other hand, the connection (interface) between 5FCI and MS8
A structure is used in which the tip of a tube 7 for guiding eluted components separated by SFC is directly introduced into an ion source maintained in a high vacuum.

[Problems to be Solved by the Invention] In this method in which the tube from the SFC is directly introduced into the ion source, the powdery eluted components precipitated at the tip of the tube are ionized as the gasified mobile phase is ejected. flows into the source. Therefore, due to the large amount of incoming mobile phase, the ionization of the eluted components is restricted to chemical ionization (CI) based forms.

In addition, impurities or eluted components that have not been vaporized may adhere to the inner wall of the ion source and contaminate it.
It is necessary to frequently break the vacuum inside the ion source and clean it, which is time-consuming. Furthermore, since a large amount of gasified mobile phase is introduced into the ion source, it is necessary to evacuate the ion source using a high vacuum pump with a large exhaust capacity, which increases costs.

SUMMARY OF THE INVENTION The present invention has been made in view of this problem, and it is an object of the present invention to provide an interface that allows ionization of eluted components separated from SFC using any ionization method.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides an ion source, a belt that is continuously introduced into the ion source from the outside, a supercritical fluid chromatograph, and a supercritical fluid chromatograph. A conduit for guiding fluid from the graph and a nozzle formed at the tip of the conduit, and the eluted component precipitated in powder form from the nozzle is deposited on the belt outside the ion source and guided into the ion source. It is composed of

Hereinafter, embodiments of the present invention will be explained in detail based on the drawings.

[Embodiment] FIG. 1 is a schematic diagram showing an embodiment of the present invention.
The same numbers as in the figures indicate the same components.

In FIG. 1, 9 is an ion source of MS8, 10 is an electrode group, 11 is a primary particle beam generator, 12° and 13 are intermediate chambers,
14 is a preliminary chamber, and 15 is a sample holding belt, which is wound around a first supply spool 16 placed on the atmosphere side. This belt 15 includes a pulley 17 and sealing means 18a, 18b.
, 18c into the ion source 9, and further, after being changed direction by the pulley 19, the sealing means 18d.

It is wound onto the second take-up spool 20 via 18e and 18f. 21 holds the belt 15 between the pulleys 1
When the pinch roller is connected to the drive motor (not shown) and rotated in the direction of the arrow, the belt 15 wound around the supply spool 16 via the pulleys 17 and 19 is ionized at a constant speed. After being introduced into the source 10, it is returned to the preliminary chamber 14 and wound onto the take-up spool 20.

Reference numeral 22 denotes a second supply spool placed in the preliminary chamber 14, and an auxiliary belt 23 is wound and held around this supply spool. Furthermore, this auxiliary belt is connected to the guide roller 24.
In the preparatory chamber 14, the eluted components, which will be described later, are placed on top of the belt 15 and introduced into the ion source 9 together with the belt 15. The auxiliary belt 23 introduced into the ion source is separated from the belt 15 by pulleys 25a and 25b (actually, there is only one pulley) arranged in parallel close to the pulley 19, and then the belt is removed again. 15 and taken out from the ion source 9.

The auxiliary belt 23 taken out from the ion source chamber is the belt 15.
After being returned to the preliminary chamber 14 together with the film, the film is taken up on the second take-up spool 26.

27 is an oil rotary pump, and 28 is a low vacuum pump such as a diaphragm type dry vacuum pump.

On the other hand, the open end 7a of the pipe 7 connected to the 5FC1 is placed so as to face and be separated from the belt 15 placed in the preliminary chamber 14. In addition, as explained in FIG. 5, the open end of the tube 7 is filled with a porous material to provide resistance, thereby maintaining the pressure within the SFC flow system at a pressure higher than the supercritical point. .

In this configuration, the powdery eluted components precipitated at the open end 7a of the tube 7 are blown out downward as the gasified mobile phase is ejected, and therefore adhere to the belt 15. At this time, the belt 15 is sequentially transferred to the ion source 10 side at a constant speed as the pinch roller 21 rotates, so the 5FC
The eluted components separated in step 1 are developed on belt 15 as a chromatogram. The developed eluted components are surrounded by the auxiliary belt 23 at the guide roller 24, and then introduced into the ion source 9 through the sealing means 18a to 18c. Then, the auxiliary belt 23 is forcibly peeled off by the pulleys 25a and 25b, and only the eluted components attached to the belt 15 are transferred to the ionization section 29 where they are ionized by the primary particle beam B. The generated ions I are extracted by the electrode group 10, accelerated and focused, and introduced into a mass spectrometry system where they are subjected to mass analysis.

Next, the auxiliary belt 23 is again placed on the belt 15 holding the eluted components that have not been ionized, and both belts are returned together into the preliminary chamber 14 through the sealing means 18d to 18f. . The belt 15 and the auxiliary belt 23 are then respectively wound onto take-up spools 20,26.

By attaching the precipitated powdery eluted components to the belt and introducing them into the ion source, it is possible to reduce only the powdery eluted components, compared to the conventional method in which the powdery eluted components were vigorously blown into the ion source together with the gas. Since it can be introduced slowly, the eluted components can be efficiently ionized.

Incidentally, if a heating means is provided in the ionization section 29 and the eluted component is heated and gasified and then irradiated with an electron beam, ionization can be performed by electron impact or chemical reaction.

FIGS. 2, 3, and 4 are diagrams showing specific examples for efficiently depositing eluted components at the tip of the tube 7 onto the belt 15. FIG.

First, FIG. 2 shows a mask 31 in which the open end 7a of the tube 7 is arranged substantially parallel to the longitudinal direction (traveling direction) of the belt 15, and a rectangular hole 30 is formed between the tube and the belt.
It is characterized by the fact that it has been installed. A heater 32 is wound around the tip of the tube, and is used to cool the tube 7 due to adiabatic expansion of the supercritical fluid of the mobile phase and to prevent frost and the like from adhering to it.

By doing this, it is possible to prevent the mobile phase gas ejected from the tube 7 from being sprayed onto the belt 15, and at the same time, only the powdered eluted components are allowed to naturally fall through the hole 30 of the mask 31 and adhere to the center part of the belt. Ru.

Next, in FIG. 3, the matrix is applied onto the belt 15 in advance by a matrix applying means (for example, a syringe pump) 33, and the powder eluted component deposited on the belt coated with the matrix 34 is passed through the nozzle 35 to an auxiliary gas. It is characterized by being sprayed together. 36
is the auxiliary gas shutoff valve.

If this is done, the eluted components are sprayed onto the matrix 34 and attached thereto, so that the eluted components can be reliably attached to the belt. In addition, since the eluted components are directionally blown by the auxiliary gas, the eluted components can be adhered to the belt without waste.

In FIG. 4, a case 37 covers the area of the tube 7 placed opposite to the belt 15, and the lower part of the case, that is, the side opposite to the tube with the belt in between, is vacuumed via an exhaust pipe 38 (not shown). It is characterized in that it is configured to be evacuated by a pump.

By doing this, a flow of gas toward the lower part is formed by suctioning the inside of the case 37 with the vacuum pump, and thereby the eluted components can be given a downward direction, so that the eluted components can be efficiently removed. It can be attached to the belt 15.

[Effect] As detailed above, according to the present invention, only the powdered eluted components can be slowly introduced into the ion source while being attached to the belt, so that the eluted components can be eluted without being affected by the mobile phase. Components can be ionized. Therefore, the ionization method of the eluted components can be arbitrarily selected, and a highly sensitive chromatogram can be obtained. In addition, since the eluted components are attached to the belt outside the ion source,
Unlike in the past, impurities and eluted components that are extremely difficult to vaporize do not adhere to the inner wall of the ion source, and there is no need to frequently break the vacuum inside the ion source for cleaning, making handling extremely easy. Furthermore, since no mobile phase gas is introduced into the ion source, a large-sized vacuum pump is not required, leading to cost reduction.

[Brief explanation of the drawing]

FIG. 1 is a schematic structural diagram showing one embodiment of the present invention, and FIGS. 2, 3, and 4 each show a concrete structure for efficiently depositing eluted components at the tip of the tube 7 onto the belt 15. FIG. 5, which is a diagram for illustrating an example, is a schematic configuration diagram for explaining a conventional example of SFC/MS. 1: SFC 2: Gas cylinder 3: Liquid pump with refrigerator 4: Injector 5: Micro force ram 6: Oven 7: Tube 8: MS 9: Ion source 11 Primary beam generator 12. 13: Intermediate chamber 14: Preliminary chamber 15: Sample holding belt 23: Auxiliary belt 31: Mask 32: Heater 34: Matrix 35: Nozzle 37: Case 38: Exhaust pipe

Claims (1)

[Claims] An ion source, a belt continuously introduced into the ion source from the outside, a supercritical fluid chromatograph, a conduit for guiding fluid from the supercritical fluid chromatograph, and a nozzle formed at the tip of the conduit. An interface in a supercritical fluid chromatograph/mass spectrometer, characterized in that the eluted components precipitated in powder form from the nozzle are deposited on the belt outside the ion source and guided into the ion source.