JPS582616B2 - Ion generator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an ion generation device, and is particularly characterized in that the sample is ionized by applying only excited species generated from a carrier gas to the sample, thereby reducing contamination of the ionization detection device. Moreover, since these reactions are carried out in the atmosphere, sample handling is extremely easy.

Ionization detectors have been widely used in the past, such as argon ionization detectors and API methods, which ionize a carrier gas with radiation or electric discharge and introduce a sample into the ionized carrier gas. The sample was ionized through reactions such as charge exchange and proton transfer from carrier gas ions, and the detection and measurement section performed detection and measurement.

However, in such cases, the sample is introduced into the carrier gas and the carrier gas and sample are ionized simultaneously, resulting in severe contamination within the detector and poor quantitative performance. The background is dog because it cannot be separated from the sample ions.

Also, since the sample needs to be vaporized in order to be introduced into the carrier gas, it cannot be used for low-volatile or non-volatile samples; it can be used for gas chromatographs, but it cannot be used for liquid chromatographs. There were deficiencies such as inappropriateness.

In view of the fact that in the prior art, the carrier gas and sample were ionized at the same time, which caused various deficiencies, the present invention provides a first chamber into which about 1,000 liters of carrier gas is introduced, and a first chamber. an exhaust passage communicating with the chamber and allowing carrier gas to flow therefrom; a needle-shaped electrode for generating corona discharge in the first chamber; and a discharge passageway for generating a corona discharge in the first chamber, and a flow of the carrier gas generated by the discharge to the second chamber. Among the charged particles and the excited species of the carrier gas moving toward
an electrode provided between the first and second chambers to prevent the passage of charged particles; and an electrode for placing the sample in the path of the excited species flowing into the second chamber with the flow of carrier gas. The method is characterized by comprising a means and a sample ionization chamber for applying an excited species to the arranged sample to ionize it.

Incidentally, the carrier gas ions and the excited species are usually generated by electric discharge, but it is also possible to use X-ray radiation, light, or other radiation.

Thus, according to the present invention, the ions of the carrier gas itself are separated and removed from the excited species, so the background is very small and the S/N ratio is good, so the detection sensitivity is accordingly high.

Furthermore, by using the excited species of the yarya gas, it is possible to directly ionize a liquid or solid sample, so there is no need to vaporize the sample.

That is, it is sufficient to simply attach a microscopic sample to a metal rod or the like and insert it into a flow of carrier gas containing excited species.

Moreover, since it is at atmospheric pressure (usually one atmosphere), both the sample introduction operation and the equipment are extremely simple.

Note that rare gases (argon, helium, krypton, etc.), nitrogen, etc. are used as the carrier gas.

In particular, when a carrier gas such as argon with an excitation energy of about 11.6 eV is used, organic compounds are ionized, but air and water are not ionized, so there is no need to make the sample introduction part airtight, so the sample can be taken in and taken out completely freely. can.

Further, according to the present invention, since the sample itself is not exposed to discharge or electron impact, there is little contamination of the apparatus due to sample decomposition.

In addition, if the liquid sample is a single compound, uses a solvent that does not ionize, or can be separated from the solvent by heating, etc., a collector (4a in Figure 1) should be provided in the intermediate part that sends sample ions to the measurement section. It can be used as a detector.

Next, an embodiment of the present invention will be explained with reference to the drawings. FIG. 1 is a side sectional view of the first embodiment, FIG. 2 is a partial top view of FIG. In the first chamber 1, the carrier gas at a pressure of about one atmosphere gives a positive or negative potential to the needle-like electrode 1b, and the electrode 1c spaced apart from this is grounded, and a high voltage is applied between them. When a voltage is applied to cause a corona discharge at the tip of the electrode 1b, a carrier gas such as argon is ionized by the discharge, and further collisions between argon ions and electrons and argon atoms are repeated to generate excited species of argon.

The reaction is given by the following equation.

The excited species thus generated flows to the right together with the carrier gas, passes through the second chamber 2, and then enters the sample ionization chamber 3, which is the third chamber.
to go into.

In chamber 2, there is one electrode in the figure, but multiple electrodes are provided as necessary between electrodes 2a and 3a, and by applying an appropriate positive or negative potential to electrode 1c, the energy generated in chamber 1 is generated. Prevent charged particles such as argon ions and electrons from entering chamber 3.

Thus, only the excited species are flowing into the chamber 3, and when a sample is introduced into the chamber 3 through the guide path or guide hole 3c, the sample is immediately ionized by energy transfer from the excited species as shown in the following equation.

Other reactions also occur.

By appropriately setting the potentials of the electrodes 3a, 3b, 4b, and 4a provided in the chamber 3, the positive or negative ions generated from the sample pass through the intermediate section 4 to the detection and measurement section 5 (first
In the figure, 4a is guided to the ion collector).

When measuring positive ions in a sample, electrode 3a has the highest positive potential, and electrodes 3b, 4b, and 4a have the lowest potential in this order.
Electrode 4a is set to earth potential.

Conversely, when measuring negative ions, the electrode 3a is kept at the highest negative potential, and the electrode 4a is also set at the ground potential.

In this way, the positive or negative ions move to the right, reach the collector electrode 4a, and are detected as a discharge.

In addition, when connecting to a mass spectrometer, a metal plate with a pinhole is used as the electrode 3b, and it is connected to an analysis tube via an ion focusing system.

Further, it is appropriate that the electrodes 1c, 2a, 3a, 4b, etc. each have a mesh-like center, but electrodes with a hole in the center may also be used.

Also, the carrier gas is passed through the guide hole or discharge passage 4c+3e, 3.
It is discharged from c.

Alternatively, background and contamination can be minimized by flowing a purge gas such as Ar or N2 through the guide hole 4c.

At this time, this purge gas is discharged from the guide hole 4d.

Furthermore, the sample may be applied and inserted onto a metal rod such as a 3D, or may be applied and introduced onto a moving wire or belt currently commercially available for liquid chromatographs.
Furthermore, it can also be introduced directly through a conduit.

Thus, according to the invention, liquid or solid (organic compound)
It is particularly suitable for detecting trace amounts of samples, is suitable for liquid chromatograph detectors, and is also used as an ion source for mass spectrometers.

Alternatively, it can be used as an interface between a liquid chromatograph and a mass spectrometer.

Further, in order to minimize contamination, a shutter can be provided on the left side of the electrode 3a in FIG. 1 and closed when not in use.

In addition, a plurality of electrodes such as 2b and 2c are provided between electrodes 2a and 3a, and appropriate positive or negative potential is applied to these electrodes, and an appropriate reagent solution is introduced to the left of electrode 3a. A so-called chemical ionization method in which a sample is ionized with reagent ions can be performed.

In addition, as a simultaneous measurement method for both positive and negative ions, an excitation probe can be introduced from above, and positive and negative ions generated from the sample can be guided to the left and right to be detected and measured at the same time.

In addition, by directly connecting a reaction device to the sample introduction port 3c, a chemical reaction can be caused on the surface of a metal rod or the like within the reaction device, and the reaction product can be immediately penetrated into the carrier gas flow path to ionize and detect and measure the reaction product. .

[Brief explanation of drawings]

1 and 2 are a side sectional view and a partial top view of an apparatus according to an embodiment of the present invention. In the figure, 1 is a first chamber for generating excited species of carrier gas, 2 is a second chamber for removing charged particles such as carrier gas ions (preventing them from entering chamber 3), and 3
Reference numeral 4 indicates a sample ionization chamber as a third chamber, 4 an intermediate section for sending sample ions to a measurement section, and 5 a sample ion detection measurement section. 3c+3e+40 is a discharge path, 1b is a needle electrode, 1c is an electrode provided between the first and second chambers, and 3c and 3d are means for placing a sample in the excited species path.

Claims (1)

[Claims] 1. A first chamber into which a carrier gas of about 1 atmosphere is introduced, a second chamber that communicates with the first chamber and into which the carrier gas flows, and an exhaust passage for discharging the carrier gas from the second chamber. , a needle-like electrode for generating a corona discharge in the first chamber, and charged particles among charged particles and excited species of the carrier gas generated by the discharge and moving toward the second chamber along the flow of the carrier gas. an electrode disposed between the first and second chambers to prevent passage of the excited species; and means for placing the sample in the passageway of the excited species flowing into the second chamber with the flow of the carrier gas. and a sample ionization chamber for ionizing the placed sample by applying an excited species to the sample.