JPH0333233B2 - - Google Patents

Description

[Detailed description of the invention] (a) Industrial application field This invention relates to an automatic sample introduction device,
It is particularly useful as a sample introduction device for high performance liquid chromatographs.

(B) Prior Art When an automatic sample introducing device sucks a sample liquid from a sample container, air bubbles are often mixed in. The air bubbles mixed in in this manner may cause errors in measurement data by the analytical instrument.

However, conventional automatic sample introduction devices have no means for dealing with air bubbles.

(C) Purpose of the Invention The present invention provides an automatic sample introduction device that monitors the inclusion of air bubbles when introducing a sample liquid into an analytical instrument, and if air bubbles are detected, reintroduces the same sample liquid again. With the goal.

(d) Structure of the Invention The automatic sample introduction device of the present invention automatically sucks a sample liquid from a sample container and supplies it to an analytical instrument. Transmitted light measurement section, reference value output section,
A comparison section that compares the output of the transmitted light measuring section and the output of the reference value output section, and when the output of the comparison section is a predetermined output, the sample liquid is aspirated from the same sample container again and sent to the analytical instrument. It is configured to include a reintroduction control section for supplying the re-introduction.

The main body of an automatic sample introduction device that sucks a sample liquid from a sample container and supplies it to an analytical instrument can be configured with a conventionally known configuration.

For example, the transmitted light measuring section has at least a part of the side wall of the sample liquid flow path transparent or semitransparent,
Basically, it can be configured by installing a light source and a light receiver in that part. Transparent here means that measurement light is transmitted through it, and is not limited to transmission of visible light.

The reference value output section may be configured with a D/A converter, for example.

The comparison section can be configured with a voltage comparator, for example.

The re-introduction control unit may be configured by, for example, a microcomputer.

(E) Embodiment 1 shown in FIG. 1 is an embodiment of the automatic sample introduction device of the present invention, which includes an automatic sample introduction device main body 2,
It comprises a transmitted light measurement section 3, a reference value output section 4, a comparison section 5, and a re-introduction control section 6.

The automatic sample introduction device main body 2 has a conventionally known configuration, and therefore will not be particularly described.

The transmitted light measurement unit 3 has a transparent side wall that forms a part of the sample flow path immediately after the sample suction needle 12 of the automatic sample introduction device main body 2, and has an infrared light emitting diode 3a and a phototransistor 3b in the transparent side wall. are placed facing each other. When there are bubbles in the transparent part P, the output level of the buffer amplifier 3c becomes high.

The reference value output section 4 consists of a D/A converter.

Comparison section 5 consists of a voltage comparator. When the output of the buffer amplifier 3c becomes higher than the output of the reference output section 4, that is, the reference value, it outputs a high level.

The re-introduction control section 6 is included in the microcomputer 8, and the microcomputer 8 also includes the main body control section 7. The reference value changes when the reintroduction control unit 6 changes the output value to the D/A converter 4.

The operation will be explained in detail below, but in the initial state, the high-pressure six-way valve 10 is in the flow path position indicated by the solid line in FIG. Assume that it is filled with liquid.

First, the re-introduction control section 6 pulls the plunger 15 of the microsyringe 14 via the plunger drive section 13 while the sample suction needle 12 is pulled up into the air. This draws air into the sample suction needle 12 and sample loop 16.

At this time, bubbles pass through the transparent portion P. As the bubbles pass through the transparent part P, the output level of the buffer amplifier 3c increases, but since the reintroduction control unit 6 is initially outputting a sufficiently large value to the D/A converter 4 and the reference value is also large, it is difficult to compare. The output of section 5 does not become high level.

When the re-introduction control unit 6 confirms that the output of the comparison unit 5 does not reach a high level, it slightly decreases the output to the D/A converter 4 to lower the reference value, and then inhales air again as described above. and pass through the transparent part P. If this is repeated, the comparator 5 will output a high level when the reference value reaches a certain level. Since this is the bubble detection level, the reintroduction control section 6 maintains the output to the D/A converter 4 at that value and fixes the reference value.

Once the reference value is fixed, the main body control section 7 expels the air sucked in for setting the reference value through the plunger 15 of the micro cylinder 14, and then performs the actual sample introduction. This rotates the turntable 18 via the turntable drive section 17 to position the desired sample container 19 directly below the sample suction needle 12, and moves the sample suction needle 12 to the sample container 19 via the sample suction needle drive section 20. The sample liquid is sucked in by pulling the plunger 15, the sample suction needle 12 is pulled up, and the high-pressure hexagonal valve 10 is
to the flow path position indicated by the broken line, and transfer the sample liquid to the column L.
This will be introduced in the future.

If no air bubbles are mixed into the sample liquid when the sample liquid is sucked from the container 19, the main body control section 7 continues the measurement as in the conventional case.

However, if bubbles are mixed in the sample liquid, the comparator 5 outputs a high level while the bubbles are passing through the transparent part P. When the re-introduction control unit 6 detects that the comparison unit 5 outputs a high level, it counts the duration of the high level and determines whether or not it is within a preset allowable time. If it is within the allowable time, it can be determined that the bubble is of negligible size or that a high level was output due to electrical noise.
The main body control section 7 ignores this and continues the measurement.
On the other hand, if it is longer than the allowable time, it means that the bubbles cannot be ignored, so the re-introduction control unit 6
The sample liquid containing air bubbles is discharged, and the sample liquid is introduced again from the previous sample container 19. As a result, if no bubbles are detected for longer than the allowable time, the main body control section 7 continues the measurement. However, if bubbles are detected for longer than the allowable time, the above-described bubble detection level setting operation is performed again to reset the bubble detection level, and then the sample liquid is introduced again from the previous sample container 19. As a result, if no bubbles are detected for longer than the allowable time, the main body control section 7 continues the measurement. However, if bubbles are detected again for longer than the allowable time, it is determined that there is no sample liquid in that sample container 19, the measurement of the sample liquid in that sample container 19 is stopped, and the sample liquid in the next sample container is introduced. to move to. Note that the allowable time is arbitrarily set by the operator.

In this manner, in the automatic sample introduction device 1, the sample liquid is reintroduced when non-negligible bubbles are detected, so that the reliability of measurement data in the liquid chromatograph can be improved. In addition, the automatic sample introduction device 1 automatically sets the optimal bubble detection level,
In addition, the length of the high level duration of the comparator output that determines that a bubble has passed can be set arbitrarily.
The reliability of the device itself will also be high.

A modified embodiment includes an AND gate that passes a clock when the output of the comparator 5 reaches a high level without using the microcomputer 8 to determine the size of the bubble, and a preset that counts down by the clock. Counter and comparator 5
One example is one in which the size of the bubble is determined by combining the preset counter with a register that sets a value corresponding to the allowable time at the rise of the output to a high level.

(f) Effects of the invention According to the automatic sample introduction device of this invention, if air bubbles are mixed in the sample liquid introduced into the analytical instrument,
Since this is detected immediately and the same sample liquid is introduced again, the reliability of the measurement data in the analytical instrument can be improved.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of the configuration of one embodiment of the automatic sample introduction device of the present invention. 1...Automatic sample introduction device, 2...Automatic sample introduction device main body, 3...Transmitted light detection section, 4...Reference value output section, 5
... Comparison section, 6... Re-introduction control section, 19... Sample container, L... Column of liquid chromatograph.

Claims (1)

[Claims] 1. In an automatic sample introduction device that automatically sucks a sample liquid from a sample container and supplies it to an analytical instrument,
A transmitted light measurement section that measures transmitted light of a part of the sample liquid flow path, a reference value output section, a comparison section that compares the output of the transmitted light measurement section and the output of the reference value output section, and the output of the comparison section. 1. An automatic sample introduction device comprising a re-introduction control unit that sucks in a sample liquid from the same sample container again and supplies it to an analytical instrument when the sample liquid reaches a predetermined output.