JPH03235055A - mass spectrometer - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a mass spectrometer, and particularly to a liquid chromatograph mass spectrometer that improves atomization of a liquid sample in order to measure the sample with high sensitivity.

[Conventional technology]

In recent years, liquid chromatographs have been developed in which a liquid chromatograph and a mass spectrometer are connected, and the liquid sample eluted from the liquid chromatograph is atomized by spraying it from a nozzle and sent to the ionization device of the mass spectrometer, where it is ionized and subjected to mass analysis. Many mass spectrometers have been proposed.

However, in order to completely ionize a liquid sample, atomization of the sample is an issue.

In order to improve this, a method has been adopted in which when the liquid sample eluted from the liquid chromatograph is transferred to the mass spectrometer using a pipe, the pipe is heated by passing it through a heater block and then injected from the nozzle ( Japanese Patent Publication No. 1-146
Publication No. 242).

In addition, as another method, a method has been proposed in which a mesoche-like obstacle is provided between the liquid sample output nozzle and the nozzle for introducing the liquid sample into the ionization chamber, and the spray is sprayed into this to achieve finer atomization. (Japanese Unexamined Patent Publication No. 153164/1983).

[Problem to be solved by the invention]

In the prior art, the former atomizes the liquid ejected from the nozzle by heating to improve the boiling phenomenon caused by the drop in pressure when the liquid is released from the nozzle to the outside, thereby making the atomization finer. It is something.

However, the droplet size of the atomized sample spreads from submicrons to more than 100 microns, making it difficult to obtain uniform particles, which prevents optimal ionization, and there is a risk that some samples may be altered by such heating. Therefore, there is a problem that sufficient atomization cannot be achieved.

In addition, in the latter case, the exit nozzle and receiver of the liquid sample are blocked by an obstacle placed between the nozzle and the atomized sample is wasted, which hinders the improvement of the sensitivity of the mass spectrometer. There is a fear.

An object of the present invention is to make the droplet size of an atomized liquid sample fine and uniform, and to provide a highly sensitive mass spectrometer equipped with the atomization device.

[Means to solve the problem]

In order to achieve the above object, the present invention includes a plurality of nozzles for ejecting a sample, and is configured to converge the ejection axis at one point.The gist thereof is as follows.

(1) A transport means for transporting a liquid mobile phase containing an object to be measured, an atomizing unit equipped with a nozzle for ejecting and electrifying the mobile phase, and ionizing or vaporizing the atomized droplet particles. In a mass spectrometer having an ionization means, a mass separation means for mass-separating the ionized ions of a measurement target, and a detection means for detecting the mass-separated ions, the atomization section has two or more nozzles. A mass spectrometer characterized in that the ejection axis of each nozzle is configured to converge at one point.

Further, the mass spectrometer according to (1), wherein the atomization section includes a heating means for heating a liquid mobile phase containing the measurement target object.

Furthermore, the mass spectrometer according to the above (1), further comprising a heating means for heating and vaporizing the analyte atomized by the atomization section, upstream of the ionization means.

[Effect]

Because the ejection axes of two or more sample injection nozzles converge at one point, the sample streams ejected from the nozzles collide with each other at the convergence point, resulting in a difference between atomization by conventional vacuum boiling and the formation of droplets between droplets. It is thought that the droplets become finer due to mechanical destruction caused by collision, and the droplet size distribution is also narrowed.

This makes it easier to ionize the atomized droplets, and the amount of ions produced, which is the information source for mass spectrometry, increases compared to those with a conventional droplet size distribution, which increases the mass spectrometer This leads to improved sensitivity.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG.

The figure shows a mass spectrometry bag Fi (L
1 is a cross-sectional view schematically showing a CMS.

The LCMS is a very useful device because it can directly analyze trace substances dissolved in a liquid.

A mobile phase 2 (for example, a solvent such as water or alcohol) is transferred to an atomization section 3 by a liquid transfer means 1 . The flow rate is generally 1
It is controlled to about mQ/min to several mQ/min. The measurement sample 4 is quantitatively injected with a microsyringe or the like, dissolved in the mobile phase, temporarily adsorbed and held in the separation column 5, and developed in chronological order by the mobile phase 2 that is sequentially transferred to the atomization section. Transferred to 3.

At this time, the flow path 20 is branched into two upstream of the atomization section 3.

In the atomizing section 3, atomization is performed by ejecting water from a nozzle 6.6' at the tip. At this time, the atomizing section 3 including the nozzles 6 and 6' may be heated by the heating means 7 in order to stabilize the atomization as necessary.

The mobile phase solution containing a small amount of sample is injected from a nozzle 6.6', atomized, and collided with each other near a focal point 8 on the ejection axis. This mechanically breaks the droplet and transforms it into smaller droplets.

When ejected from the nozzle, the droplet size was widely distributed from submicrons to about 100 microns, but
It was confirmed that by colliding the droplets in the manner described above, the size of the droplets was several microns at most, and the distribution range of the droplet size was also narrowed.

In addition, the flow path direction of the atomized droplets after collision is the nozzle 6.6.
It was also confirmed that the ejection directions from ' are combined and converted into one direction as shown in FIG.

The atomized droplets introduced into the ionization section 9 are vaporized. If heating is required for vaporization at this time, heating can be performed by the heating means 10.

Next, the atomized droplets introduced into the ionization section 9 are ionized by corona discharge generated by the high voltage generator 11 and the discharge electrode 12.

In this example, the ions were forcibly ionized, but depending on the vaporization conditions, they may exist as molecular ions. In this case, the potential of the discharge electrode 12 may be set to be the same as that of the container.

The interior of the ionization section 9 is evacuated under reduced pressure by a decompression exhaust means 13 to facilitate introduction of the atomized sample from the atomization section.

The ionized particles pass through an orifice 14 and a mass separation means 17 placed in a container 16 evacuated to a high degree of vacuum by a vacuum pump 15, and are output as a signal by a detector 18.

In this embodiment, an example is shown in which the atomizing section 3 has two nozzles, but it may have three or more nozzles.

In addition, the use of a so-called two-fluid nozzle that simultaneously ejects gas from the tip of the nozzle 6, 6', and the combined use of the heating means 7, can provide a stable atomization effect, so if necessary, It may also be used.

Furthermore, in this embodiment, ionization is performed under atmospheric pressure in front of the orifice 14, but the ionization is not limited to this, and may be performed in a high vacuum region where the mass separation means 17 is arranged. good.

In this case, ionization of the filament by hot electrons is appropriate.

FIG. 2 shows the results of comparing the droplet particle distribution between the atomization according to this embodiment and the conventional atomization using a single nozzle method.

As is clear from the figure, in the case of this example, the particle size in the liquid after atomization is uniform, and the average particle size is about 1 μm, which is smaller than that of the conventional case.

As a result of the above, the measurement sensitivity can be increased by about one order of magnitude compared to the conventional method.

〔Effect of the invention〕

According to the present invention, the particle size of droplets after atomization can be reduced and the particle size distribution thereof can be narrowed.

Therefore, since it is uniformly vaporized during vaporization, there are fewer portions that are ionized before being sufficiently vaporized, unlike in the conventional method, so that measurement sensitivity can be increased.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing the configuration of a mass spectrometer according to an embodiment of the present invention, and FIG. 2 is a graph showing the distribution of particle diameters in a liquid after atomization. DESCRIPTION OF SYMBOLS 1...Liquid feeding means, 2...Mobile phase, 3...Atomization part,
4... Sample, 5... Column, 6, 6'... Nozzle, 7, 1o... Heating means, 8... Axis convergence point, 9...
Ionization section, 11... High voltage generator, 12... Discharge electrode, 13... Decompression exhaust means, 14... Orifice, 15... Vacuum pump, 16... Vacuum container, 17
. . . Mass separation means, 18 . . . Detector, 20 . . . Channel.

Claims (1)

[Scope of Claims] 1. An atomization unit including a transfer means for transferring a liquid mobile phase containing a measurement target, and a nozzle for spraying and atomizing the mobile phase;
A mass spectrometer comprising an ionization means for ionizing or vaporizing atomized droplet particles, a mass separation means for mass-separating the ionized ions of a measurement target, and a detection means for detecting the mass-separated ions. A mass spectrometer, wherein the atomizing section has two or more nozzles, and the ejection axis of each nozzle is converged at one point. 2. A liquid mobile phase and a transport means for transporting the mobile phase;
Atomization comprising an injection means for injecting an analysis sample into the mobile phase, a separation column for adsorbing and separating the mobile phase containing the analysis sample, and a nozzle for spraying and atomizing the mobile phase containing the separated measurement target. a part, an ionization means for ionizing or vaporizing the atomized droplet particles, a mass separation means for mass-separating the ionized ions of the measurement target, and a detection means for detecting the mass-separated ions. A liquid chromatograph mass spectrometer having a liquid chromatograph mass spectrometer, wherein the atomizing section has two or more nozzles, and the ejection axis of each nozzle is converged at one point. Device. 3. The mass spectrometer according to claim 1 or 2, wherein the atomizing section includes heating means for heating the liquid mobile phase containing the measurement target. 4. The mass spectrometer according to claim 1 or 2, further comprising a heating means upstream of the ionization means for heating and vaporizing the analyte atomized by the atomization section. 5. A liquid mobile phase and a transport means for transporting the mobile phase;
Atomization comprising an injection means for injecting an analysis sample into the mobile phase, a separation column for adsorbing and separating the mobile phase containing the analysis sample, and a nozzle for spraying and atomizing the mobile phase containing the separated measurement target. a part, an ionization means for ionizing or vaporizing the atomized droplet particles, a mass separation means for mass-separating the ionized ions of the measurement target, and a detection means for detecting the mass-separated ions. In the liquid chromatograph mass spectrometer, the atomizing section has two or more nozzles, the ejection axis of each nozzle is configured to converge at one point, and the atomizing section includes the object to be measured. A liquid chromatograph mass spectrometer, comprising a heating means for heating a liquid mobile phase, and a heating means for heating and vaporizing the analyte atomized by the atomization section upstream of the ionization means. .