JPH0415555A - Interface for mass analysis - Google Patents

Abstract

PURPOSE:To improve sepn. accuracy and to assure sepn. by separating a moving phase by the condensation and evaporation utilizing the difference in b.p. between a sample and the moving phase. CONSTITUTION:A liquid mixture composed of the sample component and moving phase from liquid chromatograph (LC) is evaporated to gas by a heating pipe 8. The gas flows from a mixture introducing port 3 into a solidifying chamber 1. This gas comes into contact with a cooling body 6. The cooling temp. of the cooling body 6 is set at the prescribed value higher than the b.p. of the moving phase and lower than the b.p. of the sample. While the gaseous sample component condenses, the gaseous moving phase does not condense and is discharged as it is from a suction discharge port 5. On the other hand, the sample component liquid flows through an outflow port 4 and a cooling passage 18 down into an evaporating ion chamber 2. While the sample component liquid flows down on a heating means 10, the liquid is heated and evaporated again in the chamber 2. This gaseous sample component is irradiated with the thermions from a filament 12 and is subjected to an electron impact method (EI) ionization. The gaseous sample component is ionized by a chemical ionization method (CI) when the gas is irradiated with the thermions after the reaction gas is introduced. The ions are then sent to a mass spectrometer.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to an interface provided between a liquid chromatograph (r, c) or a gas I chromatograph (CC) and a mass spectrometer.

(b) In conventional liquid chromatography mass spectrometers, I7C is
The sample is separated into components in time series, and the subsequent mass spectrometer separates the ions of each sample component by mass. therefore,
At an intermediate stage between the LC and the mass spectrometer, sample components must be ionized by chemical ionization (CI) or electron impact (ET).

In addition, the effluent from the LC is a mixture of sample components and mobile phase, but if the mobile phase interferes with the ionization of sample components or mass spectrometry, the mobile phase should be mixed. It needs to be removed from the body.

The same situation applies to gastronomy mass spectrometers.

Conventionally, an interface installed at an intermediate stage between an I7C or GC and an old mass spectrometer has a configuration as shown in FIGS. 3 to 6.

■ Figure 3 shows a thermospray interface for LC, in which the effluent from the LC is heated in a heated capillary tube 1o, so that both sample components and the mobile phase constituting the effluent are heated. vaporize,
These gases are introduced into the ion source box 2°. In the ion source box 2°, ionization by CI is also performed using the inflowing mobile phase gas as a reaction gas. In the thermospray interface, in particular, thermospray ionization by ion evaporation without EI or CI is combined with CI using a filament or a discharge electrode.

■ Figure 4 shows a particle beam interface for LC. In this interface, the effluent from the LC is injected into a skimmer 4o with a nebulizer 3°, inertial separation of the mobile phase is carried out, and the mobile phase The removed sample components are introduced into the ion source box 2o. In addition,
In fact, the ion source box 2° is directly connected to the rear part of the simmerer.

■ Figure 5 shows the interface of a backed column type GC. In this interface, the sample component gas from the GC is sent together with the mobile phase gas to a jet separator 5°, where the mobile phase is inertially separated. It is introduced into the ion source box 2°.

■ Figure 6 shows the case of capillary column type GO,
The flow rate of the mobile phase in this GC is low and it is thought that it will not have a major effect on mass spectrometry, so the outlet of the GC is directly connected to the ion source box 2°, and the mixture of sample components and mobile phase is The gas is directly introduced into the ion source.

(c) Problems to be Solved by the Invention'' Conventional interfaces as described above have the following problems.

However, in the thermospray interface for LC described in (2), since the vaporized mobile phase is also supplied to the ion source, CT ionization using the mobile phase residue as a reaction gas is possible in the ion source, but E Ionization cannot be performed.

Furthermore, most of the mixture is vaporized by heating the heating capillary tube 1°, but it is difficult to maintain the heating temperature of the heating capillary tube 1° at the required temperature. Sensitivity changes significantly and adversely affects analytical results. Furthermore, since the mobile phase is a reactive gas, the types of reactive gases are limited.

On the other hand, ■In each of the following interfaces, El
Both ionization and CI ionization are possible, but in the particle beam interface for LC described in (2), the molecular weight of the mobile phase is considerably larger than that of helium, which is the mobile phase of GC, so it is difficult to inertially separate the mobile phase sufficiently. Therefore, a small amount of the mobile phase was fed into the ion source box 2o, which caused a problem in ionization.

In the back column type GC interface described in (2), the flow rate of the mobile phase is high and a large amount of mobile phase must be separated, but in order to improve the separation performance of the mobile phase, increasing the pumping speed at 5° of the jet separator Sample component gases other than the mobile phase gas will be exhausted. Therefore, it was difficult to reliably separate the mobile phase, and it was also impossible to separate some component gases among the sample components.

In the case of the capillary column type GC (2), since sample component gas and mobile phase gas flow into the ion source, ionization is inhibited by the flowing mobile phase gas, resulting in poor ionization efficiency.

In this way, conventional interfaces include those that remove the mobile phase and those that do not. Those that remove the mobile phase perform inertial separation of the mobile phase, resulting in low separation accuracy and There is a problem in that a portion of the ion source flows into the ion source and adversely affects ionization and mass spectrometry. Also,
At measurement sites, it is sometimes desirable to remove some of the sample components for mass spectrometry, but it is difficult to separate some of the sample components using inertial separation.

On the other hand, interfaces that do not separate the mobile phase have drawbacks such as the inability to perform ET ionization in the ion source, low efficiency even if EI ionization is possible, and the inability to use any reaction gas even if CI ionization is possible. was there.

The present invention was made in view of the above-mentioned problems, and it separates the mobile phase by condensation and vaporization, improves the separation accuracy of the mobile phase, and makes it possible to ionize both EI and CI. Furthermore, it is an object of the present invention to enable the separation of any component other than the mobile phase with simple condition settings.

(d) Means for Solving the Problems In order to achieve the problems set forth in 1, the present invention provides a system that is provided between a T, C, or GC and a mass spectrometer, and which includes a condensation chamber and a vaporization chamber. ionization chamber, and the condensation chamber is L.
A mixture inlet that introduces a mixture of a mobile phase and a sample from C or GC in a gaseous state, a cooling body that cools the introduced mixture gas so that necessary high boiling point components are condensed, and a condensing liquid. The vaporization ionization chamber has an inlet for introducing the condensed liquid flowing out from the condensation chamber, a heating means for heating and vaporizing the introduced liquid, and a filament and an inlet for introducing the condensed liquid flowing out from the condensation chamber. , )・wrap electrode,
A mass spectrometry interface was constructed that included a reactant gas introduction port and an ion exit hole.

(E) Function In the above configuration, when used as an interface for I and C, a mixture of sample components and mobile phase, which are the effluents of T and C, is vaporized by heating and introduced into the condensation chamber. This mixed gas is cooled by contacting the cooling body. Generally, the boiling point of the sample component is higher than the boiling point of the mobile phase, and the temperature of the cooling body is set to a value between the two boiling points. Therefore, the sample components are condensed and liquefied, but the mobile phase is not condensed.
The gas is sucked and exhausted from the exhaust port. The mobile phase is now separated.

The liquefied sample components flow down to the next vaporization ionization chamber, where they are heated by the heating means and vaporized again. The sample component gas is irradiated with thermoelectrons from the filament, thereby ET ionizing the gas. Furthermore, after introducing the reactive gas, the sample component gas is ionized by CI ionization by irradiating it with thermoelectrons.

In the case of GC, since the mixture of sample components and mobile phase is a gas, it is introduced into the condensation chamber as it is.

The subsequent action is similar to that of the LC described above.

(f) Examples The present invention will now be described in detail based on examples shown in the drawings.

FIG. 1 is a configuration diagram of an LC/mass spectrometry interface according to an embodiment of the present invention.

As shown in the figure, the interface of this example is
It is connected after the LC and includes a condensation chamber I and a vaporization ionization chamber 2. The condensing chamber l is the first box l.
a, the gas ionization chamber 2 is composed of a first box 1a
It consists of a second box 2a placed below the.

A first box Ia constituting the condensing chamber 1 has a mixture inlet 3, an outlet 4, and a suction/exhaust port 5, and a cooling body 6 is provided inside. 7 is a heater that warms the entire first box la.

A heating tube 8 communicating with the LC column outlet is connected to the mixture inlet 3, so that a mixture of the mobile phase and the sample is introduced in a gaseous state from the mixture inlet 3. It has become. As the heating tube 8, for example, a vaporizing tube having a double tube structure and whose outer tube generates heat when energized is used.

The cooling body 6 cools the introduced mixture gas so that the sample, which is a high boiling point component, is condensed, and in this example,
It consists of multiple pipes that cross the inside of the condensing chamber. A cooling liquid flows through the pipe, and its temperature is set higher than the boiling point of the mobile phase and lower than the boiling point of the sample.

The suction/exhaust valve 5 is for exhausting uncondensed gas, that is, mobile phase gas, and is designed to be sucked in by an exhaust pump (not shown).

The outlet 4 is for sending out the sample component liquid, which is a condensed liquid, and opens at the bottom of the first box Ia.

The second box 2a constituting the vaporization ionization chamber 2 is
Located below the box 1a, the second box 2a is provided with an inlet 9, a heating means IO, and a drain outlet 11, and further includes a filament 1 for ionization.
2, the electron entrance hole 13, the L/wrap electrode 14, the trap hole I5, the reactive gas inlet 16, and the ion exit hole 1.
7 is provided.

The inlet 9 is for introducing the sample component liquid, which is the condensed liquid from the outlet 4 of the condensation chamber 1, and the inlet 9 and the outlet 4 of the condensation chamber 1 are connected to the inclined cooling passage 18. It is connected in communication. One is the coolant piping around the cooling passage 18.

The heating means 10 is for revaporizing the condensed liquid, and in this example, it consists of an inclined plate IOb with a built-in heater 10a,
The second box 2a extends from the inlet 9 to the drain outlet 11.
It is installed diagonally to form the bottom plate of the

The filament I2 is disposed outside the electron incidence hole I3, and the trap electrode 14 is disposed outside the trap hole 15.
is facing. 20 is a suction exhaust [].

Reference numeral 21 denotes a waste liquid reservoir, which communicates with the drain outlet 11 of the vaporization ionization chamber 2 through a drain pipe 22, and has a heater 23 inside.

In the configuration described in item 1, the mixed body fluid of the sample component and the mobile phase, which is the effluent from the LC, passes through the heating tube 8 and is heated and vaporized, becoming a gas and condensing from the mixture inlet 3. Introduced into chamber 1.

This mixed gas contacts the cooling body 6 and is cooled. Here, in general LC, the boiling point of the mobile phase is lower than the boiling point of the sample, and by utilizing this fact, the cooling temperature of the cooling body 6 is set to a predetermined value higher than the boiling point of the mobile phase and lower than the boiling point of the sample. It is set. Therefore, although the sample component gas is condensed, the mobile phase gas is not. The mobile phase gas is then exhausted as it is from the suction bow exhaust [5]. Since the sample components are in liquid form, they are not exhausted. The mobile phase will now be separated.

The sample component liquid flows down into the next vaporization ionization chamber 2 through the outlet 4 and the cooling passage 18 .

In the vaporization ionization chamber 2, the sample component liquid is heated while flowing down over the heating means 10 and vaporized again.

Here, a part of the sample component gas generated by revaporization flows back into the cooling passage I8, but since the inner wall of the cooling passage I8 is cooled and sloped, the sample component gas flows back into the cooling passage 18. It condenses when it touches the inner wall of the chamber, becomes a liquid, and flows back into the vaporization and ionization chamber 2. Therefore, vaporized sample components do not flow back to the condensation chamber 1.

The sample component gas generated by revaporization is transferred to the filament 12.
By being irradiated with thermionic electrons from the electron beams, the E-densities are ionized.

In addition, if thermionic electrons are irradiated after introducing the reactive gas,
The sample component gas is CI ionized. Sample component ions are sent out from the ion exit hole 17 to a subsequent mass spectrometer.

The sample component liquid that has not been vaporized in the vaporization ionization chamber 2 passes through the drain pipe 22 from the drain outlet II to the waste liquid reservoir 2.
1 will be collected. Therefore, no sample component liquid remains on the heating means 10.

It should be noted that the cooling body 6 can easily maintain a constant cooling temperature, and by setting the cooling temperature appropriately, in addition to the mobile phase,
Part of the sample components can be separated and removed.

The cooling body 6 is not limited to a tube like the one shown in FIG. 2, but may also be a plate as shown in the longitudinal sectional view of FIG. 2(A) and the front view of FIG. 2(B). The plate-shaped cooling body 6 can suppress the flow of the mixture gas to the suction/exhaust port 5, and can discharge only unnecessary gas such as mobile phase gas.

The configuration of the above embodiment can also be applied to a GC/quality analysis interface as is, so illustrations and explanations of the configuration of this GC compatible interface will be omitted.

In the case of GC, since the mixture of the mobile phase and sample components that is the effluent is a gas, there is no need for a means to vaporize the mixture as in the embodiment shown in FIG. directly,
It may also be introduced into the condensation chamber 1.

Usually, a heater is provided around the mixture introduction pipe in order to keep the temperature of the mixture gas from decreasing and to prevent adsorption to the inner wall of the pipe. 0°C water may be allowed to flow through the cooling body 6 as a cooling liquid.

Even with this GC compatible interface, the condensing chamber I
The sample components were condensed and liquefied in step 2, while the mobile phase was removed by suction and exhaust without being condensed, and the liquefied sample components were vaporized in vaporization ionization chamber 2. (J, same as in the embodiment of FIG. 1).

In the embodiment mentioned above, the sample components were vaporized and ionized within one room of the vaporization ionization chamber 2, but the vaporization and ionization chamber 2 was divided into a space for vaporization and a space for ionization. The sample component gas generated in the vaporization space may be supplied to the ionization space.

(G) Effects of the Invention As described above, in the present invention, both the LC effluent and the GO effluent are treated by utilizing the difference in boiling point between the sample and the mobile phase, and by condensing and vaporizing the mobile phase. Since the mobile phase is separated, the accuracy of mobile phase separation is high, and the mobile phase can be reliably separated and removed, and the sample component gas from which the mobile phase has been removed can be ionized as either ET or CI. can.

In this case, for F]I ionization, there is almost no mixing of mobile phase gas, so ionization can be performed efficiently, and CI
In ionization, any reaction gas can be freely selected.

Moreover, by changing the cooling temperature of the cooling body, the separation conditions for the mobile phase etc. can be set appropriately.Moreover, the cooling temperature of the cooling body can be easily maintained constant, and the separation conditions are stable. Separation of any sample components can also be performed.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of one embodiment of the present invention, and FIG. 2 shows a cooling body of another embodiment, in which (A) is a longitudinal sectional view and (B) is a front view. 3 to 6 are all schematic configuration diagrams of conventional examples. 1 Condensation chamber, 2 Vaporization ionization chamber, 3 Mixture inlet, 4 Outlet, 5 Suction exhaust port, 6 Cooling body, 8 Heating tube, 9 Inlet, 10 Heating means, 12... Filament, ■4... Trap electrode, 16... Reaction gas inlet, 17... Ion exit hole.

Claims (1)

[Claims] (1) It is installed between the LC or GC and the mass spectrometer, and includes a condensation chamber and a vaporization ionization chamber, and the condensation chamber contains a mixture of the mobile phase and sample from the LC or GC. A mixture inlet that is introduced in a gaseous state, a cooling body that cools the introduced mixture gas so that required high boiling point components are condensed, an outlet for the condensed liquid, and a suction and exhaust port for the gas that is not condensed. The vaporization ionization chamber includes an inlet for introducing the condensed liquid flowing out from the condensation chamber, a heating means for heating and vaporizing the introduced liquid, a filament, a trap electrode, a reactive gas inlet, and an ion emission hole. An interface for mass spectrometry, comprising: