JPS6128940B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a chromatograph in which a sample is introduced into a column by means that do not cause loss of the sample.

In general, a sample introduction device for a liquid chromatograph or gas chromatograph sequentially sucks and samples a sample from a large number of sample containers arranged on a turntable through a sample suction tube, and then switches the flow path of the sampled sample to a carrier. It is introduced into the column by means of a fluid. Conventionally, this sample introduction device has a flow path configuration as shown in FIG. 1 and is generally used. In the figure, the samples 2 in the sample containers 1 arranged on a turntable (not shown) are in the suction hole 3 on the side of the tip of the sample suction needle 3.
Through H, the sample is sampled as 2' into the sample loop 5 by the suction force of the microsyringe 4. During this sampling, the two-way tubes 6 and 7 communicate with the flow path indicated by the solid line. In order to feed the carrier 9 into the column 8 in the direction of arrow a during this sampling, a flow path switching section 12 having a liquid feeding pump 10, a carrier flow rate adjusting resistor 11, and a seal chamber 14 is provided in the flow path. This flow path switching section 12
An inhalation needle 3 passes through the inhalation needle 3, and this inhalation needle is slidably supported by a high-pressure sealing member 13 made of, for example, Teflon. A space sealed at the top and bottom by this seal member (hereinafter referred to as a seal section) 13 is a seal chamber 14, and a hole 17, which communicates with the intermediate ends 15, 16 of the carrier flow path, is provided on the side surface of the seal chamber 14.
18 is open. An enlarged sectional view of the flow path switching section 12 including the seal chamber 14 is shown in FIG. Components with the same symbols as in FIG. 1 will not be explained. The central through-hole of the casing 19 is formed to have an inner diameter Dφ slightly larger than the outer diameter dφ of the inhalation needle 3, and an annular portion having a width of (Dφ−dφ)/2 forms the seal chamber 14. The seals 13 are each tightened with a hexagonal head bushing 20. The figure shows the suction needle 3 being pulled up a distance L in the direction of arrow C from the sample suction position in Figure 1, and the suction hole 3
The figure shows a state in which H is stopped in the seal chamber 14 at a position facing the communication hole 18 provided on the side surface thereof. When the inhalation needle 3 is returned to the position shown in FIG. 1 and moved to the position shown in FIG. 2, the sampling channels indicated by solid lines in the two-way sockets 6 and 7 are closed, and the channels indicated by dotted lines are alternately opened. At the same time, the valve 21 opens and the carrier 9 flows mostly in the direction of the dotted arrow b due to the fluid resistance of the carrier 9, pushing the sample 2'' in the sample loop 5 in the direction of the dotted arrow b. 3 from the suction hole 3H to the seal chamber 14
After filling the space, the sample components are introduced into the column 8 from the communication hole 18 via the flow path 16 by the carrier 9, and the separated sample components are detected by the detector 22. In the conventional sample introduction device described above, the main analysis channel system (21 → 6 →
5→3H→14→16→), the seal chamber 14
A seal portion 13 is present on the downstream side of the suction hole 3H of the suction needle 3. This is a drawback that if leakage occurs in the seal portion 13, not only the carrier 9 but also the sample will be lost. This is particularly problematic in the case of automatic sample introduction devices. Furthermore, even during normal periods when the seal part does not wear out, the seal chamber forms a rapidly expanding section of the cross-sectional area of the main analysis flow path, so once the sample enters the seal chamber, it diffuses and spreads, and all of this is transferred to the column. It takes a little more time to be sent to the flow path than in the case of a straight flow path with a uniform cross section,
In other words, there is also the problem that the sample spreads in the flow direction of the main analysis channel, causing tailing at the peak of the chromatogram.

The present invention has been made in view of the above-mentioned current situation, and is intended to solve the drawbacks and problems of conventional sample introduction devices for liquid chromatographs or gas chromatographs. This refers to the direction of flow in the main analysis flow path, where a sample is sampled from the sample reservoir through the sample intake tube into the sample holding tube by suction or pressure injection, and then the sampled sample is introduced into the column using the carrier fluid. By switching the flow path so that the flow direction is the same as that when sampling the sample into the sample holding tube, the leak-prone seal part in the main analysis flow path can be moved upstream from the intake part of the sample intake tube. This is what we were able to do with the configuration. That is, the seal chamber is hermetically divided by a pair of upper and lower seal members, and has a seal chamber that is connected to the carrier fluid feeding means through a communication hole as appropriate, and a suction hole on the side surface near the tip. a sample intake tube that closely penetrates a seal member and is slidably supported by the seal member, the suction hole reciprocating between the opening position of the communication hole in the seal chamber and the sample storage section; a sample holding tube for holding the sample sampled by the sample taking means; and a sample sampling flow path or sample holding tube for taking the sample from the sample storage section into the sample holding tube through the sample taking tube. In the chromatograph, the seal part of the seal chamber is connected to the sample intake tube when switching to the main analysis flow path. The chromatograph is arranged upstream of the reverse inlet hole to form a flow path from the carrier fluid feeding means to the column via the communication hole, the seal chamber, the sample intake tube, and the sample holding tube. It depends on the graph.

Embodiments of the present invention will be described below with reference to the drawings. FIG. 3 is a block diagram showing the configuration of a liquid chromatograph using the sample introduction device of the present invention. Components with the same symbols as in FIGS. 1 and 2 will not be explained.
31 is a high-pressure 6-way switching valve (hereinafter referred to as valve)
6 ports A to F and solid line flow paths 32, 3
It has three flow paths, 3 and 34, and can be switched alternately in the directions of arrows d and e. The figure shows valve 3 above.
1 is switched in the clockwise direction d indicated by the dotted line, and the channels 32, 33, and 34 indicated by the solid lines are connected to form a sample sampling channel. turntable 3
Reference numeral 3 indicated by a dotted line in the sample reservoir (sample container) 1 above 5 is a sample intake tube, which in this embodiment is the sample suction needle described in FIGS. 1 and 2. When the plunger 4P of the microsyringe 4 is pulled in the direction of the arrow f when the suction needle is in this position, the suction needle 3, the sample loop 5 and the flow path of the valve
The carrier 9' filled in the pipe containing the sample 4 is sucked into the microsyringe 4, and a predetermined amount of the sample 2' is sucked and sampled into the sample loop 5. The sample loop 5 is a flexible spiral pipe made of glass, for example, supported by an upper end 5P, and expands and contracts as the suction needle 3 connected to the other end moves a certain distance L. During this sampling operation, the carrier 9 sent by the pump 10 is sent to the column 8 and the detector 22 via the port C of the valve 31, the channel 33, and the port D, and is discharged to the drain reservoir 36. Next, when the suction needle 3 is pulled up in the direction of arrow C and stopped so that the suction hole 3H of the suction needle is located at the position shown by the solid line, that is, the regular position in the seal chamber 14 explained in FIG. 2, the valve 31 is opened. Switch to counterclockwise arrow e. By this switching, the flow paths 32, 33, and 34 shown in solid lines are closed, and the flow paths 32', 33', and 34' shown in dotted lines are opened instead, and the carrier 9 sent by the pump 10 is transferred from port C to flow path 33'. → Port B → Piping 37 → Seal chamber 1 via communication hole 17
Flows into 4. After the carrier 9 fills the seal chamber 14, it flows into the suction needle 3 through the suction hole 3H, and sweeps the sample 2' sampled in the suction needle 3 and the sample loop 5 upward. This swept away sample 2' is at port E of valve 31→
It is sent to column 8 via flow path 34'→port D. This is the main analysis flow path, and in this flow path system, the seal portion 13 of the seal chamber 14 is placed upstream of the suction hole 3H, which is the sample intake portion of the suction needle 3. This is the essential part of the present invention; the carrier 9 flows into the seal chamber 14, but the sample 2' does not. Therefore, even if the seal portion 13 is worn, only the carrier will leak, and no valuable sample will leak. After introducing the sample 2' into the column 8, open the electromagnetic valve 38 and push the plunger 4P of the microsyringe 4 in the direction of arrow g. Since the water is sealed, it is discharged from the drain port 39 via the electromagnetic valve 38. This completes one cycle of sample suction and introduction into the column, and when the next sample container 1' is positioned directly below the suction pipe 3 by rotation of the turntable 35 at a certain angle, the valve 31
is switched in the direction of the dotted arrow d, and the suction needle 3 is similarly moved in the direction of the dotted arrow h, and its suction hole 3H is inserted into the sample container. The electromagnetic valve 38 is also closed.
The subsequent operation is as described above.

Although not shown, in the case of a gas chromatograph, the sample introduction device of the invention is applied to an apparatus that samples a liquid sample and then vaporizes it or introduces a gas sample into a column together with a carrier gas. In addition to the above-mentioned needle for inhaling a sample with a microsyringe, the sample intake needle also includes a needle-like device for applying pressure to a sample container and pushing the sample into it. Further, in the above embodiment, the sample intake needle was described, but in addition to the needle-shaped needle with a sharp tip, a tube-shaped needle (sample intake tube) as shown in the drawings may also be used.

Since the present invention is configured as described above, the sample taken in from the suction hole is pushed into the intake tube by the carrier fluid from the suction hole in the seal chamber and is carried to the column, and the sample is transferred into the seal chamber. will not spread. In other words, the sample is not lost due to deterioration of the seal or leakage, and the entire sample can be correctly used for analysis. Furthermore, since there is no diffusion due to the sample in the sealed chamber, tailing and peak broadening of the chromatogram can be prevented.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing the configuration of a conventional liquid chromatograph sample introduction device, Fig. 2 is a sectional view showing the structure of the sample intake tube seal chamber used in the above device, and Fig. 3 is a block diagram showing the structure of the sample introduction tube seal chamber used in the above device. FIG. 2 is a block diagram of a sample introduction device for a liquid chromatograph according to an example. DESCRIPTION OF SYMBOLS 1...Sample storage part, 2...Sample, 3...Sample intake tube, 3H...Sample intake part of the sample intake tube, 4...Microsyringe in the sample sampling channel, 5...Sample in the sample sampling channel Holding tube, 8... Column, 9... Carrier fluid, 10...
... Pump for sending carrier fluid, 13 ... Seal part, 14 ... Seal chamber, 1 → 3 → 5 → 4 ... Sample sampling channel, 10 → 14 (13) → 3H →
3→5→8...Main analysis channel.

Claims (1)

[Scope of Claims] 1. A seal chamber that is hermetically divided by a pair of upper and lower seal members and is connected to the carrier fluid feeding means in a flow path through appropriate communication holes, and a seal chamber that is inlet on the side surface near the tip. The suction hole has a hole that closely penetrates the seal member and is slidably supported by the seal member, and the suction hole connects between the opening position of the communication hole in the seal chamber and the sample storage section. A reciprocating sample intake tube, a sample holding tube that holds the sample sampled by the sample intake means, and a sample sampling channel that takes the sample into the sample holding tube from the sample reservoir via the sample intake tube. Alternatively, in a chromatograph equipped with a flow path switching means for selectively switching the main analysis flow path through which the sample taken into the sample holding tube is sent to the column using a carrier fluid, when switching to the main analysis flow path, the seal chamber is closed. The seal portion is arranged upstream of the suction hole of the sample intake tube, and forms a flow path from the carrier fluid feeding means to the column via the communication hole, the seal chamber, the sample intake tube, and the sample holding tube. A chromatograph featuring: 2. The chromatograph according to claim 1, wherein the flow path switching means is a six-way switching valve.