JPH02132371A - capillary column - Google Patents

Abstract

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

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Industrial Application Field This invention relates to a capillary column for gas chromatography.

(Example) Prior Art Conventionally, a capillary column used in a capillary column gas chromatograph has a uniform inner diameter over its entire length, and is used by being connected to a detector as is.

(c) Problems to be Solved by the Invention However, in the capillary column described above, the detector connected to the column outlet is under atmospheric pressure, so when a sample is analyzed using such a system, the components separated by the column are The closer the carrier gas gets to the outlet, the lower the carrier gas pressure becomes, making it easier to diffuse, and as a result, the peak becomes broader.

The present invention was made in view of this situation, and it is an object of the present invention to provide a capillary column for gas chromatography that can prevent the diffusion of separated components.

(2) Means for Solving the Problems Thus, according to the present invention, there is provided a capillary column for gas chromatography, in which the flow path is reduced in cross-section at or near the outlet end on the detector connection side of the column. A capillary column is provided that has an inner diameter changing portion that can be narrowed.

The present invention provides a capillary column for gas chromatography, which is configured to increase the flow resistance downstream of the column flow path so that each separated component separated in the upstream region can be transferred to a detector while preventing diffusion. It is characterized by

In this invention, the inner diameter changing portion is provided at or near the exit end of the capillary column on the detector connection side. The above-mentioned vicinity may be the column side from the column outlet end, or may be the detector connection side. The above inner diameter changing part is
It is formed in a structure that can narrow the flow path by reducing the cross section of the flow path.

The above-mentioned reduction is set to a sufficient degree to prevent diffusion of separated components. Therefore, it is preferable to set the flow path resistance to be at least twice the flow path resistance of the main body of the capillary column.

(For example, if the pressure just before the exit of the separation capillary column is 1
kg/c. m' (gauge pressure) or more is preferable. ) Structures that can narrow the flux include a structure that narrows the flow path by increasing the thickness of the column wall around the capillary column outlet end;
Examples include a configuration in which the column wall at or near the outlet end is stretched to narrow the flow path, and a configuration in which a tube with a small cross section is connected to the capillary column outlet end.

In the present invention, it is preferable that a pressurizing flow path is provided in the inner diameter changing portion so that the degree of increase in flow path resistance can be adjusted. A preferred configuration example for this purpose includes, for example, using a three-way joint at the outlet end of the gear villa column to provide a second carrier gas inflow path, and providing a pressure regulator in this carrier gas inflow path.

The capillary column of the present invention may have any configuration known in the art, except for the configuration in which the flow path resistance is increased in the downstream section.

(E) Effect According to the present invention, the capillary column has an inner diameter changing portion at or near the outlet end connected to the detector to restrict the flux, and the carrier gas near the capillary column outlet Attenuation of the pressure is prevented, and as a result, the separated components separated in the upstream section are introduced into the detector while maintaining their separated state.

EXAMPLES The present invention will be explained in detail below with reference to Examples, but the present invention is not limited thereby.

(F) Examples Example 1 FIG. 1 is a partial configuration explanatory diagram of an example of a capillary column of the present invention. The figure shows the structure of the end of the capillary column on the detector connection side.

In other words, this capillary column is made of chemically bonded methyl silicon (length 25 m, inner diameter 0.32 mm, film thickness 5 μm).
A normal gas chromatograph capillary column (1) made of
．． : 10 μm) pores (A) were formed. The ratio of the flow path cross section at the mouth of the column body to the flow path cross section at the pore (a) was I/1024.

Example 2 FIG. 2 shows a partial configuration explanatory diagram of another example of the capillary column of the present invention. The capillary column shown in the figure is a capillary column (1) similar to that used in Example 1, which was melted and stretched at the outlet end while flowing an inert gas into the column to form a thin tube, and then cut. It is.

The inner diameter (d,) of the thin tube portion (c) at the outlet end of the obtained capillary column was 8 μm. At this time, the ratio of the flow path cross section at the mouth of the column body to the flow path cross section at the tip pore (C) was 1/1600.

Embodiment 3 FIG. 3 shows a partial configuration explanatory diagram of another embodiment of the capillary column of the present invention. The capillary column shown in the same figure is a capillary column (1) similar to that used in Example 1, with an inner diameter (d.: 5
0 μm) and a capillary tube (3) with a length of 0.25 m. The capillary tube (3) is a quartz tube whose inner surface has been inertly treated, and the union (2) has a Vespel ferrule (4) therein that connects and holds the outlet end of the capillary column (1) and the end of the capillary tube (3). ) etc. At this time, the ratio of the cross section of the flow path at the mouth of the column body to the cross section of the flow path of the capillary tube (3) was 1/41.

Regarding the gear pillar column obtained in Example 3, one of the indicators expressing its separation ability is the theoretical plate height (HETP).
): HETP=L/N (L: column length, N: total number of theoretical plates) was studied. That is, the Cabillarinorum of Example 3 was analyzed under the following conditions using a gas chromatograph, and H
When the relationship between E T P (mm) and linear velocity (am/see) was investigated, the HETP curve (λ) shown in FIG. 4 was obtained. At this time, as a comparative example, HETP obtained using a normal capillary column (1) under the same conditions as above.
Curve (b) is also shown.

〔Analysis conditions〕

Column temperature: 180°C Carrier gas. Helium split ratio: 30:1 Sample: n-C+t compound (in n-penkun) From the results shown in Figure 4 above, the H E T P value of the former is lower than that of the latter, and the resolution is improved. You can see that

Embodiment 5 FIG. 5 is a partial structural explanatory diagram of another embodiment of the capillary column of the present invention. The capillary column in the same figure connects a capillary column (1) similar to that used in Example 1 and a capillary tube (3) used in Example 3 with a three-way joint (5). (5
) is connected to a carrier gas supply path (c) from a carrier gas supply section (not shown) via a pressure regulator (6) and a pressure gauge (7). This allows the flow resistance of the capillary column to be increased at any ratio by adjusting the carrier gas pressure in the carrier gas supply path (c).

(G) Effects of the Invention According to the present invention, it is possible to suppress the diffusion of components separated in a capillary column near the outlet, and it is possible to improve separation performance.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of a partial configuration of one embodiment of a capillary column of this invention, FIGS. 2 and 3 are explanatory diagrams of a partial configuration of another example of a capillary column of this invention, and FIG. 4 is an explanatory diagram of a partial configuration of an embodiment of a capillary column of this invention. FIG. 5 is a HETP curve diagram showing the improvement in resolution of an example of a capillary column according to the present invention together with a comparative example. FIG. (1)・・・・・・・・・Caserari column, (2)...
・Union, (3)... Capillary tube, (5)...
... Three-way joint, (6) ... Pressure regulator, (7) ... Pressure gauge. Fig. Fig. Fig. Line 1i [Ul (cm/sec) Fig. C

Claims (1)

[Claims] 1. A capillary column for gas chromatography, comprising:
A capillary column that has an inner diameter changing section that can reduce the cross section of the flow path and restrict the flux at or near the outlet end on the detector connection side of the column. 2. The capillary column according to claim 1, wherein a pressurizing carrier gas flow path is connected to the inner diameter changing portion.