JPS59120955A - Gas chromatograph - Google Patents

Abstract

PURPOSE:To enable analysis of a dilute sample by changing over heating control and the flow of a carrier gas for a sample evaporating chamber, removing the solvent occupying the greater part in a sample solvent and introducing only the intended component into a capillary column. CONSTITUTION:A sample soln. is dropped through a septum 5 onto silica wool 6 in a sample evaporating chamber. The temp. in this state is set at about the temp. at which only the solvent in the sample soln. can evaporate. Stop valves 1, 3 are closed and a stop valve 2 is opened so that the carrier gas passes through a pressure regulator 8 and the valve 2 then through the inside of an inside cylinder 7 and is released to the outside through the valve 1. The solvent having high volatility in the sample soln. is therefore evaporated and is discharged through a discharging part 22 to the outside of the system. The valves 1, 2 are then closed and the valve 3 is opened to reverse the flow direction of the carrier gas in the cylinder 7; at the same time, a heater 8 is energized to heat quickly the sample evaporating chamber 18 and to evaporate the intended component remaining in the wool 6. The component is fed into a capillary column 6 and is detected suitably with a detector 10.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a gas chromatograph, and in particular provides a gas chromatograph that enables analysis of dilute samples.

In gas chromatography, a capillary column (for example, 0.2 to 0.5 mm≠) is often used as the main column, but because the inner diameter of the capillary column is small, it is usually difficult to use a sample (solution) due to the column load.
~ /io (sprint) and pumped into the capillary column. Therefore, if the sample is a dilute solution (low concentration component), analysis is often difficult in terms of detection sensitivity (for example, analysis of biological samples such as steroids and organic acids in urine).

Of course, there is also a method of introducing most of the sample containing dissolved Kk into a capillary column for analysis, but there is a risk that the capillary column will deteriorate due to a large amount of solvent.

This invention was made in view of these circumstances, and its specific configuration includes a sample vaporization cylinder, sample heating temperature control means,
A carrier gas switching supply means for supplying the carrier gas to the sample vaporization cylinder in a switchable manner in all flow directions, and a cavity barrel extending from one opening of the sample vaporization cylinder to the detector, and the sample heating control means and the carrier gas switching supply. By operating the means, unnecessary components such as the solvent in the sample solution injected into the sample vaporization tube are removed from the other opening of the sample vaporization tube, and then the target components in the sample solution are vaporized and transferred to the capillary column. This is a gas chromatograph configured to introduce

In other words, this invention makes it possible to introduce only the target components into the capillary column, excluding the solvent gold that occupies most of the sample solution, by controlling the heating of the sample vaporization chamber and switching the carrier gas flow. It enables sample analysis.

The present invention will be described in detail below based on embodiments shown in the figures. Note that this invention is not limited to this.

First, in FIG. 1, the gas chromatograph (G) consists of an outer cylinder (15) and a sample vaporization inner cylinder (or glass insert) (7), which is coaxially placed inside the outer cylinder. : Fully equipped, (16) is the support ring of the inner cylinder, (i7) is the seal ring. Also, on (1st day), in the sample vaporization chamber of the inner cylinder (7), (
6) is the silica wool filled in the vaporization chamber, and (9) is the capillary column extending from the rear opening (19) of the inner cylinder to the detector (10) (e.g., inner diameter 0.3 ran d, length 25 m). ). On the other hand, (5) is the septum installed in the front opening (20) of the outer cylinder (15), (21) is the septum holding plate, (22) is the exhaust part, and (23) is the outer cylinder (15).
The seal ring of the rear opening (24), (25) the first carrier gas supply section near the opening (24), and (26) the support ring (17). This is the second carrier gas supply section on the opposite side.

In addition, (11) is a high flow path resistance, (27) is a variable flow path resistance, (1) Vi on-off valve, (2) and (3) are on-off valves,
(29) is a pressure regulator, (12) is a high flow path resistance (variable split resistance), (31) is a makeup gas (or scavenger gas) inlet, and (2nd day) is a column tank.

(30) is a sample heating cylinder installed in the body around the outer cylinder (15). Air or nitrogen cooled from the cylinder via a cooler can be passed inside the cylinder, and outside the cylinder. A heater (8) is wound around the tube, and the temperature of the sample vaporization chamber (1 day) in the inner cylinder can be controlled by controlling the heater.

First, take a certain amount of sample t into the microsyringe (4), and pour the sample solution through the septum (5) into the sample vaporization chamber (
1 day), drop it onto the silica wool in the sample vaporization chamber.At this time, the temperature in the sample vaporization chamber (1 day) should be a temperature that allows only the solvent in the sample solution to evaporate (e.g. room temperature to 70℃). ℃
(depending on the solvent, of course).

In addition, the on-off valves (1) and (3) are closed, and the on-off valve (2) is opened, and the carrier gas passes through the pressure regulator (8) and the on-off valve (2), and then passes through the entire interior of the inner cylinder (7). It escapes to the outside through the pressure on/off valve (1), and therefore the highly volatile solvent in the sample solution evaporates and is discharged to the outside of the system through the exhaust section (22).

Next, open/close valves (1) (2) 'f! : Closed, open/close valve (
3) Open the inner cylinder (7) completely by 4 degrees to allow the carrier gas to pass through in the flow direction, and at the same time fully operate the heater (8) to rapidly heat the sample vaporization chamber (18) (e.g. 300°C). -/L' (6) completely vaporizes the target component, sends it to the capillary column (9), and sends it to the detector (10) as appropriate.
Detected by. In this way, the analysis of the test shot is performed only on the target components excluding the melt 11, which accounts for the majority, and therefore, even if the sample is a dilute sample, highly sensitive analysis is possible.

Note that after rapid heating, the sample vaporization chamber (1 day) is cooled with cold air for the next sample introduction.

Among the sample heating temperature control means adopted in the above examples, the heating means is a means of coating the outside of the inner cylinder (made of glass) with a metal film or inserting a paramagnetic metal entirely inside the inner cylinder and performing high-frequency heating. However, in either case, care must be taken to prevent the vaporized components from coming into contact with the metal surface and causing decomposition.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal sectional view showing an embodiment of a gas chromatograph according to the present invention. (7)... Sample vaporization inner cylinder, (8)... Heater, (
9)...Capillary column, (1)...Detector, (
22)...Exhaust section, (25)...First carrier gas supply section, (26)...Second carrier gas supply section. Agent Patent Attorney Shintabe Nogawa

Claims (1)

[Scope of Claims] 1. A sample vaporizing tube, a sample heating temperature control means, a carrier gas switching supply means for supplying a carrier gas to the sample vaporizing tube in a switchable flow direction, and a detector from one opening of the sample vaporizing tube. By operating the sample heating control means and the carrier gas switching supply means, unnecessary components such as the solvent in the sample solution injected into the sample vaporization tube are discharged from the other opening of the sample vaporization tube. A gas chromatograph configured to remove a target component from a sample solution, then vaporize the target component in the sample solution and introduce it into a capillary column.