JPS6066155A - Detector for light absorption and ionization - Google Patents

Abstract

PURPOSE:To enable simultaneous measurement of light absorption and ionization with simple and small-sized constitution by providing a means for emitting UV light of a prescribed wavelength and a means for detecting said light on the opposite sides of an ionizing chamber for a gaseous sample and providing means for detecting ion in the position where the UV light is not shielded. CONSTITUTION:A vacuum UV lamp 3 which is a light emitting means to release UV light of <=200nm wavelength and a photoelectric tube 4 which is a photodetecting means are provided respectively on the opposite sides of an ionizing chamber 2 for a gaseous sample provided with an inlet and outlet for the gaseous sample so that the light absorption of the gaseous sample is measured. On the other hand, a high-voltage electrode 5a which accelerates ions and a collector electrode 5b which collects the ions are provided on the inside surface on the other opposite sides of the chamber 2 in the position where the UV light by the lamp 3 is not shielded. The ionization by the UV light of the gaseous sample is measured by such electrodes. The simultaneous measurement of the light absorption and ionization of the gaseous sample is thus made possible by the above-mentioned simple and small constitution.

Description

Detailed Description of the Invention (a) Industrial Application Field The present invention relates to a light absorption ionization detector that can detect both light absorption and light ionization of a sample gas, and is particularly useful as a gas chromatograph detector for qualitative analysis. It is useful in

(b) Prior Art A photoionization detector (from P) is known as a detector capable of extracting ionization of a sample gas by light.

However, it is not possible to examine the optical absorption of the sample gas using P, so when you want to examine the optical absorption, it is necessary to separately install a light emitting means and a light detecting means in the sample gas flow path, which makes the structure complicated and the detection There is an inconvenience that the space occupied by the container becomes too large.

No. P Purpose of the Invention The object of the present invention is to provide a gas chromatograph detector that can detect both light ionization and light absorption of a sample gas, has a simple structure, and can be made compact. .

B) Structure of the Invention The detector of the present invention detects both light absorption and light-induced ionization of the sample gas, so it is called a light absorption ionization detector. A sample gas ionization chamber with a wavelength of 200 nm provided on one side of the sample gas ionization chamber.
a light-emitting means capable of emitting ultraviolet light of less than m, a light-detecting means provided opposite to the light-emitting means on the other side of the sample gas ionization chamber, and substantially blocking light rays transmitted from the light-emitting means to the light detecting means. The sample gas ionization chamber is provided with an ion detection means provided in the sample gas ionization chamber at a position where the sample gas ionization chamber is not exposed.

The reason why the light emitted from the light emitting means is ultraviolet light with a wavelength of 200 nm or less is because it is difficult to detect the absorption of light by gas if the wavelength is larger than 200 nm, and the wavelength is too short to ionize the gas. This is because it is preferably 150 nm or less.

(e) Example (1) shown in the diagram is an example of the light absorption ionization detector of the present invention, which includes a sample waste ionization chamber (2), a vacuum ultraviolet lamp (3), a phototube (4), and a direct pressure It basically consists of 414 electrodes (5 electrodes) and a collector electrode (5b).

The sample gas ionization chamber (2) is made of Y71 insulating ceramic, and has a sample gas inlet (2) at the bottom and a sample gas outlet (2bJ) at the top. The sample gas flows from the bottom to the top inside the sample gas ionization chamber (2) and is discharged to the outside.

A vacuum ultraviolet lamp (3) is provided on one side of the sample gas ionization chamber (2) and irradiates high-energy light into the sample gas ionization chamber (2) through a window (6) made of an alkali metal salt. (3aJ (3bJ is the electrode of the lamp (3).

The phototube (4) is provided at a position facing the vacuum ultraviolet lamp (3) via the sample gas ionization chamber (2).

A photocurrent corresponding to the intensity of the received light flows through the window (7) made of alkali gold ffft salt, and the photocurrent is converted into voltage by an electrometer and recorded on a recorder.

This makes it possible to detect light-absorbing substances in the sample gas.

The high voltage electrode (5a) and the collector electrode (5b) constitute ion detection means. When the sample gas is ionized by the energy of high-energy light in the sample gas ionization chamber (2), the ions are accelerated by the high-voltage electrode (5a) and collected at the collector electrode (5b), causing an ion current to flow. The ion current is converted into voltage by an electrometer and recorded on a recorder. This allows detection of ionized substances in the sample gas.

Other examples include those using a windowless helium or argon discharge tube as the light emitting means, and those using a photomultiplier tube as the light detection means.

(f) Effects of the Invention According to the light absorption ionization detector of the present invention, information on both ionization and light absorption of the sample gas can be obtained, so it is possible to perform qualitatively more effective analysis than using either one alone. can. A particularly useful analysis target is the analysis of pharmaceuticals using a capillary column.

Furthermore, since the light absorption ionization detector of the present invention occupies a small space, there is an advantage that the analyzer can be constructed in a compact size.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of a vertical cross-sectional configuration of an embodiment of a light absorption ionization detector of the present invention, and FIG. 2 is an explanatory diagram of a cross-sectional configuration of the same. (1)...Light absorption ion detector, (2)...Sample gas ionization chamber, (3)...Vacuum ultraviolet lamp, (4)...Phototube,
(5s...high voltage electrode, (5bJ...collector electrode).

Claims (1)

[Scope of Claims] 1. A sample gas ionization chamber having a sample gas inlet and an outlet, a light emitting means provided on one side of the sample gas ionization chamber and emitting ultraviolet rays with a wavelength of 200 nm or less into the sample gas ionization chamber; A light detection means provided opposite the light emitting means on the other side of the sample gas ionization chamber, and a light detection means provided in the sample gas ionization chamber at a position that does not substantially block the light beam transmitted from the light emission means to the light detection means. A light absorption ionization detector comprising ion detection means provided. 2. The light absorption ionization detector according to claim 1, wherein the sample gas ionization chamber is made of highly insulating ceramic. 3. The light absorption ionization detector according to claim 1 or 2, which comprises a light emitting means or a vacuum ultraviolet lamp. 4. Claims 1 to 4, wherein the light detection means comprises a phototube.
The light absorption ionization detector according to any one of Item 3. 5. The light absorption ionization detector according to any one of claims 1 to 4, wherein the ion detection means comprises a direct pressure electrode and a collector.