JP2609084B2 - Method for introducing a sample from a liquid chromatograph to the ionization part of a mass spectrometer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention belongs to the fields of industry, medicine, medicine, etc. utilizing a liquid chromatograph and a mass spectrometer. More specifically, the present invention relates to a method for introducing a liquid sample sent from a liquid chromatograph into a mass spectrometer.

[0002]

2. Description of the Related Art Conventionally, a direct connection between a micro liquid chromatograph and a mass spectrometer has been made using a relatively simple introduction capillary (such as a glass capillary). The eluate from the liquid chromatograph is introduced into the above capillary and ionized in the ionization chamber of the mass spectrometer.

[0003]

At this time, the local heating of the tip of the capillary is delicate and difficult to control, and it is difficult to introduce a high boiling point compound or a thermally unstable compound.

[0004] The present invention has been found by closely observing the behavior of samples and eluents from liquid chromatographs in an inlet capillary installed in a vacuum.

[0005] Observation of the behavior of the capillary of the direct connection between the liquid chromatograph and the mass spectrometer using a microscope television shows that in the conventional method, a liquid-gas interface exists near the tip of the capillary and remains at a certain location. Was found. It has been found that when the high boiling color compound comes near the tip, it either stays at this interface or stays at a slightly vaporized location and does not escape from the capillary into the vacuum.

[0006]

In order to solve this problem, the liquid-gas interface at the tip is physically moved back and forth, and the moving tip of the interface is brought very close to the tip of the capillary. And found a good thing. It has been found that the high boiling point compounds are easily released into a vacuum when the interface is continuously moved back and forth, and reaches the ionization chamber. The front boundary can be moved back and forth easily by adding a new heating section to the rear end of the capillary inside the liquid chromatograph and mass spectrometer direct connection, or by applying vibration to the liquid introduced into the capillary. Becomes

[0007] Further, by adjusting the heating of the tip to a low temperature, the tip of the capillary can be kept at an appropriate low temperature, and the eluate can be solidified together with the sample at the tip of the capillary and can be protruded into a vacuum in a solid state. Was. In this method, a sample is continuously introduced into a vacuum through two processes of (1) eluent-solidification-sublimation or (2) eluent-solidification-sublimation and vaporization after liquefaction using an ion beam or the like. A new way to go.

The method is applicable to eluents for liquid chromatography and high density gases used for supercritical chromatography.

[0009]

The sample introduced from the liquid chromatograph is introduced into the vacuum without stopping at the capillary by constantly moving the liquid-gas interface in the capillary back and forth, and is ionized.

Further, by adjusting the temperature of the capillary tip of the direct coupler to a low temperature and solidifying the liquid at the capillary tip and introducing it in a solid state in a vacuum, the sample in the capillary which is easily seen in the liquid can be observed. No residue occurs. Because no heat is applied,
It is advantageous for handling heat labile compounds.

Further, since an ion beam or a light beam is directly applied to a rod-shaped solid for ionization, ionization can be performed from the entire sample as compared with the case where an ion beam is applied to a part of a dispersed sample such as a powder. Sample can be used effectively, the amount of ionization is large, and measurement at a high concentration can be performed.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail based on an embodiment shown in the drawings. However, this does not limit the invention.

FIG. 1 shows an embodiment of the present invention, in which a direct coupling is enlarged. From the liquid chromatograph, the eluent is introduced into the capillary (2) in the direct connection device, and is vaporized by heating the tip. At this time, the back-and-forth movement of the liquid-gas interface (3) is repeated vigorously and continuously from the capillary tip (3 '), that is, from (3) to (3'). This repetition may be achieved by providing a rear heating section (5) in addition to the front heating section (4) behind the capillary.

Alternatively, a three-way connecting pipe may be provided at the connection between the capillary (2) and the liquid chromatograph, and mechanical pulsation may be transmitted from one of the connecting pipes to the eluent to be introduced.

FIG. 2 shows the same apparatus as in FIG. 1, except that the heating temperature of the heating section (4) is adjusted to a low temperature so that the liquid eluate is solidified at the tip of the capillary, solidified, and evacuated. A way to guide inside.

The applied eluent is water-based, acetone-water-based,
Salt-containing systems, organic solvent systems, and the like.

The sample introduced was solidified together with the eluent, and when observed with a colored sample, it was observed that the moving color solidified and moved without expanding the sample band.

[Brief description of the drawings]

FIG. 1 is a diagram showing a direct connection between a liquid chromatograph and a mass spectrometer as the liquid-gas interface continuously moves back and forth.

FIG. 2 shows a direct method of continuously solidifying a liquid and introducing it into an ionization section.

[Explanation of symbols]

(1): Eluent from liquid chromatograph (2): Glass capillary with an inner diameter of 30 micrometers (3): Boundary surface where liquid turns into gas (3 '): Boundary when (3) in the figure moves Surface (4): Front heater (5): Rear heater (6): Flow of gas or fine droplets of eluent and sample vaporized (7): Eluent (liquid) (8): Interface where eluent changes from liquid to solid (9): solidified eluent

Claims (2)

(57) [Claims] A liquid which is introduced from a liquid chromatograph through a capillary for direct introduction to a vacuum side in a mass spectrometer is solidified by a low-temperature adjusting means provided at a tip portion of the capillary for direct introduction to form a rod-shaped solid. And projecting the rod-shaped solid into a vacuum in the mass spectrometer and introducing it into the ionization section of the mass spectrometer. 2. A liquid which is introduced from a liquid chromatograph through a capillary for direct introduction to a vacuum side in a mass spectrometer and is solidified by a low-temperature adjusting means provided at a tip end of the capillary for direct introduction to form a rod-shaped solid. Is formed, the rod-shaped solid is projected into a vacuum in the mass spectrometer, and the rod-shaped solid is directly ionized by applying an ion beam, or the rod-shaped solid is irradiated with a light beam to cause sublimation or evaporation. A method in which the obtained gas is ionized and introduced into the ionization section of the mass spectrometer.