JPS6287856A - Method and apparatus for injecting specimen for capillary gas chromatography - Google Patents

Abstract

PURPOSE:To enable analysis with high resolving power and high sensitivity by an inexpensive simple system, by removing only a solvent from the specimen protruded from the leading end of the needle of a microsyringe and adhered to the leading end of a press rod before drawing said specimen excluding a solvent into the needle. CONSTITUTION:In high resolving power gas chromatography using a capillary column, a specimen is protruded from the leading end of the needle of a microsyringe 10 to be adhered to the leading end of a push rod 3 and only a solvent is removed from the specimen in this state to draw said specimen into the needle. Next, the push rod 3 in the needle 2 is protruded to introduce the specimen into the column 5. By this method, the specimen can be injected in the column 5 so that the volume thereof becomes small and a pulse width becomes short.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to high-resolution gas chromatography using a capillary column in analytical chemistry.

[Prior Art] As shown in FIG. 8, a sample turned into a gas at a sample injection part r into which a carrier gas q is introduced together with a sample p is passed through a column S on a carrier gas.

In gas chromatography, which detects the separated components with a detector t to determine the contained components, capillary gas chromatography is used in which the column is very elongated in order to improve the separation of components and increase accuracy and sensitivity. There is. In order to maintain the high resolution characteristic of capillary gas chromatography, it is necessary to shorten the pulse width during sample injection as much as possible. Conventionally, three main types of methods have been proposed to satisfy this condition. That is, A) A split υ in which the sample injected as a solution is vaporized in the vaporizing section and then split into two channels, a column and a vent, and only a portion of the sample is introduced into the column.

B) Splitless method, in which the sample injected as a solution is trapped at a low column temperature and separated by gradually raising the temperature, cool on-column method, and direct method using a thick capillary column.

C) A moving needle method in which only the solvent is vaporized with the needle L, and then the needle is moved to the heating section to vaporize the sample.

and so on.

"Problems to be Solved by the Invention" However, in the split method A), the ratio of the flow rates divided into two channels is the split ratio (generally 1150
Since only a portion of the injected sample is introduced into the column (approx. ~17,100), it is unsuitable for analyzing low-concentration samples.

In the splitless method (B), when the vaporized sample is injected, it flows only through the column, and after being liquefied and trapped in a low-temperature column, it is analyzed at elevated temperature. After injecting the sample directly into the column with a microsyringe.

Perform temperature rise analysis. However, this submerging/dressing method requires elevated temperature analysis, which has disadvantages such as expensive equipment, easy baseline fluctuation, and long analysis time.

In addition, the Coulomb column method also has drawbacks such as rapid deterioration of the column detector since non-volatile components are also introduced into the column.

Furthermore, since the latter direct method uses a thicker column, it is a method that is contrary to capillary gas chromatography.

In the moving needle method (C), a sample solution is attached to a needle that has been raised to a low temperature range, and only the solvent is vaporized using a carrier gas flowing in the opposite direction of the column.
By lowering the needle to the heating section, the remaining sample is vaporized and introduced into the column by carrier gas. However, this method not only requires special equipment and is expensive, but once set, it is not easy to remove, and it can only be installed on vertical models. Additionally, cleaning the needle is troublesome and time consuming. Furthermore, this method requires a large moving space for the needle, and does not introduce the sample with a short pulse of 1 [1], which is short enough to fully utilize the column capacity. There are drawbacks such as the fact that it cannot be used.

The present invention aims to solve the shortcomings of the two-legged prior art, and its objectives are, firstly, to provide an inexpensive and simple system that can be connected to a conventional capillary column; Second, the sample is introduced into the column with an extremely short pulse width to fully utilize the high resolution of the capillary column. Third, high-sensitivity analysis is possible. Fourth, the system can be easily replaced and cleaned. and fifth, to expand the application of the moving needle method to lower boiling point compounds.

``Means for Solving Problems R'' We will describe an injection method for gear pilar gas clostography and its sample injection device to solve the problems listed above.

First, in the capillary gas chromatography injection method of the first invention, a sample attached to the tip of a push rod protruding from the needle tip of a microsyringe is drawn into the needle, removing only the solvent. The needle is inserted into a two-way injection port connected to the column, and then the push rod inside the needle is pushed out to introduce the sample into the column. In this way.

This is a method in which a sample is injected into a capillary column so that its volume is small and the pulse width is short.

Further, the sample injection device for capillary gas chromatography of the second invention connects an injection tube having a trumpet-shaped injection port into which a needle of a sample injector can be inserted to the base end of a capillary column in capillary gas chromatography. put.

On the other hand, a cylinder having a push rod insertion hole in the axial direction, a tubular needle formed protruding from the tip of the cylinder and having the push rod insertion hole extending in the axial direction, and a cylinder that is slid in a tight state into the push rod insertion hole. Prepare a sample injector consisting of a pusher cup that fits freely.

The push cup of this sample injector is formed so that its tip can protrude from the needle when pushed in, and
This is a sample injection device for capillary gas chromatography, characterized in that a sample reservoir recess is formed at the tip of the push rod, which is narrower than the inner diameter of the needle.

It goes without saying that an injection tube having a trumpet-shaped injection port may be detachably connected to the base end of the gear pillar column. Note that the sample reservoir recess that is narrower than the inner diameter of the needle means that the tip of the push rod is formed into a stepped thin section, a recess is formed at the tip of the push rod, or the tip of the push rod is formed with an appropriate shape. It is sufficient to drill a groove in the shape of .

Furthermore, in the present apparatus, it goes without saying that an injection tube having a trumpet-shaped injection port may be detachably connected to the base end of the gear pillar column.

``Example'' Below, examples of the present invention will be explained in detail with reference to the drawings. In the present invention, the needle part of the conventional moving needle method is made independent outside the system and replaced with a modified sample injector. As shown in FIG. 1, the tip of the push rod 3 that goes in and out of the needle 2 of the sample injector L is configured to protrude from the tip of the needle 2, and the tip of the push rod 3 is
A sample reservoir recess 4 is formed which is narrower than the inner diameter of the needle 2, a sample is attached to the sample reservoir recess 4, only the solvent is removed, and the needle 2 is drawn into the needle 2.The needle 2 is then inserted into the column 5 and the Teflon tube 7 is inserted. This is a sample injection method and sample injection device in which the sample is inserted into a trumpet-shaped injection port 8 of an injection tube 6 connected via a needle 2, and a push rod 3 inside the needle 2 is pushed out to introduce the sample into a column 5. In the figure, 9 is a detector connected to the tip of the column 5.

In the present application, as shown in FIG. 2, the injection tube 6 has a sample injection port 8 that is open in a trumpet shape so that the tip of the needle 2 of the sample injection tube 111 can smoothly enter the sample injection port 8. In addition, it is a capillary tube in order to minimize the dead space in the vaporization section, and the inner diameter of the joint with the column 5 is made to match that of the column 5 to avoid dead weight (mL) and turbulence. It becomes.

The injector 6 is detachably connected to the column 5, and the connected portion is airtightly connected via a Teflon tube 7. Of course, this injector 6 and column 5
may be fixed to.

On the other hand, as shown in FIG. 3, the feed injector 1 includes a cylinder 12 having a push rod insertion hole 11 in the axial direction, and a push rod insertion hole 1 protruding from the tip of the cylinder 12 and extending in the axial direction.
The needle 2 is made up of a tubular needle 2 that extends from the needle 1, and a push rod 3 that is slidably fitted in the push rod insertion hole 11 in a tight state. In Figure 1, 13 is a push rod guide.

In order to reduce the dead space as much as possible, the shape of the sample reservoir recess 4 at the tip of the needle 2 and push rod 3 can be varied depending on the sample as shown in Figs. 5 and 6. I can do it.

In this application, the structure of the sample reservoir recess 4, which serves as the sample attachment part at the tip of the push rod, is a standard stepped thin structure 4a as shown in FIG. 4(A), but it may be changed depending on the sample. Alternatively, it is also possible to form a small diameter recess 4b as shown in FIG. Also, in the same figure ()\), a spiral groove 4C is attached to the sample reservoir recess 4, and a large amount can be deposited at one time.

In use, as shown in Fig. 3, a certain sample solution is applied to the sample reservoir recess 4 at the tip of the push rod 3 of the sample injector I using an ordinary microsyringe lO, and after vaporizing the solvent, the push The rod 3 is drawn into the needle 2 and inserted into the trumpet-shaped injection port 8 which is the sample injection section. When the tip of the needle 2 has entered the inside sufficiently, the push rod 3 is pushed out, and the sample adhering to the rod 9 is vaporized and introduced into the ram 5.

Since the injection port of the injection tube 6 is trumpet-shaped, insertion of the sample injector 1 of the present invention is extremely smooth, and the injection port of the injection tube 6 is in the shape of a trumpet.
By making the connections as thin and short as possible to eliminate dead spaces, the resolution does not decrease, and the joint with the column 5 is simple and there is no dead space and no gas leaks.

"Effects of the Invention" First, the injection method of the present invention, which is the first aspect of the present invention, is characterized in that the sample attached to the tip of the push rod protruding from the tip of the needle of the sample injector is
Since only the solvent was removed and drawn into the needle, 6 of the injected sample
In addition, this needle was inserted into a trumpet-shaped inlet connected to the capillary column, and the push rod inside the needle was pushed out to introduce the sample into the column, so the sample was vaporized in the thin part of the column. As a result, the pulse width becomes narrower. As a result, the injection method of the present application has a higher theoretical plate number than the conventional split method, etc., and tailing in the chromatogram is reduced, so high resolution that fully utilizes the fl and power of the column can be obtained.

The injection method of the present application is a system in which the entire amount of sample injected enters the detector, so highly sensitive analysis is possible.

In the injection method of the present invention, an injection tube is provided and heating and vaporization is performed within the injection tube, and temperature control is not required, so low-temperature analysis can be performed. Incidentally, in the present invention, it goes without saying that temperature elevation analysis can also be performed selectively.

The second aspect of the present invention apparatus comprises an injection tube connected to the proximal end of a capillary column and a sample injector independent from this system, and the injection tube has a wrapper into which the needle of the sample injector can be inserted. In addition to forming the mold injection port, the tip of the push rod of the sample injector was formed so that it could protrude from the needle, so the sample could be easily inserted into the column with a pulse width.
High resolution can thereby be obtained.

Furthermore, since the pulse width becomes small even without raising the temperature, constant temperature analysis is possible.

The device of the present invention can disassemble the capillary column, the injection tube, the cylinder and needle of the sample injector, and the push rod, making it easy to clean, making it possible to use non-volatile oil, and having a low boiling point. Applications to compound analysis will be expanded. Furthermore, since the device can be easily disassembled and cleaned, there is less contamination and less deterioration of the constituent members.

The device of the present invention can be easily disassembled and reassembled, so handling is carried out inside the cylinder, and each component can be replaced depending on analysis conditions such as column diameter and sample, so it can be installed on any model. The scope of application becomes wider.

Furthermore, the device of the present invention has a simple configuration of each part, and the pulse 11) is small and the analytical performance can be improved without the need for auxiliary devices such as a heating device, so the manufacturing cost is lower than that of the conventional device, making it highly economical. Become something.

As described above, the present invention is superior to conventional methods in terms of analysis, operability, and economy.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing the entire system configuration of the apparatus of the present invention, FIG. 2 is a longitudinal side view of the sample injector, FIG. 3 is a longitudinal side view of the injection tube, and FIGS. 4(a) and (b). (C) is a side view showing an embodiment of the feed reservoir recess of the push rod, and FIG. 5 is a configuration diagram of the gas chromatography apparatus. 1... Sample syringe, 2... Needle. 3...Push rod, 4...Sample reservoir recess, 5...Column. 6... Injection tube. 8...Trumpet-shaped injection port.

Claims (4)

[Claims] (1) Pull the sample attached to the tip of the push rod protruding from the needle tip of the sample injector into the needle, excluding only the solvent, and insert the needle into the trumpet-shaped injection port connected to the capillary column. A sample injection method for capillary gas clostography characterized by introducing a sample into a column by protruding a push rod inside the column. (2) An injection tube having a trumpet-shaped injection port into which the needle of a sample injector can be inserted is connected to the base end of the capillary column in capillary gas chromatography, and the injection tube has a push rod insertion hole in the axial direction. It consists of a cylinder, a tubular needle that is formed protruding from the tip of the cylinder and has a push rod insertion hole extending in the axial direction, and a push rod that is slidably fitted in the push rod insertion hole in a tight state. A sample syringe was prepared, and the tip of the push rod of the sample syringe was formed so that it could protrude from the needle, and a sample reservoir recess that was smaller than the inner diameter of the needle was formed at the tip of the push rod. A sample injection device for capillary gas chromatography characterized by the following. (3) The sample injection device according to claim 2, characterized in that an injection tube having a trumpet-shaped injection port is detachably connected to the base end of the capillary column. (4) The sample reservoir recess that is narrower than the inner diameter of the needle refers to the case where the tip of the push rod is formed into a stepped thin section, when the tip of the push rod is formed with a recess, or when the tip of the push rod is formed with a recess. The sample injection device according to claim 2, which includes a case where a groove is bored in the shape of.