JPS6258462B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrophoretic spectrometer, and more particularly to an electrophoretic spectrometer equipped with means for detecting passage of a certain ionic component zone through a predetermined position of an electrophoresis tube. This invention relates to a migration spectrometer.

In an electrophoretic spectrometer, it is necessary to detect that a certain type of ionic component zone is passing through a predetermined position in the pipe, especially when separating a target component from a sample, or conversely, when separating a target component from a sample, or conversely, detecting the passage of a certain ionic component zone through a predetermined position in a pipe. This occurs when removing components. Conventionally, this detection means has been disclosed in Patent Office Document No. 76-53349 (Journal of
Chromatography, 119, 1976), page 10, the detector originally included in the electrophoretic spectrometer also has the function of the detection means, or as described in Japanese Patent Publication No. 8302-1983. It is known that a similar detector is provided separately from the original detector at a predetermined position in the electrophoresis channel.

However, in the former case, the application is limited because detection can only be performed at the position where the detector is originally installed, and in the latter case, another detector must be installed in the electrophoresis tube. Therefore, the device becomes complicated and there is also a risk of interaction with the sample.

The present invention has been made in view of the above circumstances, and provides an electrophoretic spectrometer that can perform the above detection at any predetermined position in a migration tube and has a relatively simple configuration. It is something.

That is, the present invention provides an electrophoretic spectrometer in which a sample injection part and a detector are connected in order by a pipe between a terminal liquid electrode tank and a leading liquid electrode tank, which are respectively connected to both ends of a constant current power supply circuit. Provided is an electrophoretic spectrometer comprising a pipe line between a sample injection part and a detector having a sudden change in pipe diameter part, and a voltage change measuring means for measuring temporal changes in supply voltage connected to a power supply circuit. do.

Specifically, the above-mentioned sudden change in pipe diameter is a constriction part where the pipe diameter becomes smaller or a bulge part where the pipe diameter becomes larger. In the case of a two-stage tube in which a thick pretube and a capillary reach tube with a narrow pipe diameter are connected in series via a stepped portion, this is the stepped portion.

Further, the voltage change measuring means is specifically constituted by, for example, an AD converter and a microcomputer. In this case, for example, the microcomputer measures the voltage between both ends of the power supply circuit via an AD converter at predetermined short intervals, and obtains the difference from the previous measurement value as the voltage change.

This voltage change is a nearly constant value when any one ion component zone is electrophoresing in the part where the diameter of the pipe suddenly changes, but it is unusual when the interface between two different ion component zones is electrophoresing. make a change.

Therefore, by detecting this unique change, it is possible to know that a certain type of ion component zone has entered the aforementioned abrupt change in pipe diameter, and it can also be known that it has exited based on the same principle. Therefore, if, for example, a preparative separation operation is performed at that timing, the preparative separation can be carried out suitably.

By the way, if the conduit between the sample injection part and the detector is the two-stage tube described above, the constant current value may be set to a large value when a liquid with high conductivity is in the capillary reach tube, but If you keep the same large current when a small liquid enters the capillary reach tube, the resistance value will increase as the pipe diameter becomes smaller, resulting in an abnormally high supply voltage and increased generation of Joule heat. Moreover, the heat causes the inconvenience that air bubbles are generated in the capillary reach tube. However, if the constant current value is set small from the beginning, the electrophoresis time will become longer. Therefore, when a liquid with low conductivity is in the pre-column, a large current is used, and when the liquid enters the capillary column, the current is reduced to a small current. It is desirable to switch.

The present invention also provides an electrophoretic spectrometer equipped with a means for automatically performing this switching, which detects a peculiar change in the output of the voltage change measuring means and detects a specific change in the output of the voltage change measuring means. The present invention provides an electrophoretic spectrometer further comprising current switching means for switching the current value of a constant current.

Specifically, the current switching means is, for example, the microcomputer and the relay means. For example, the microcomputer detects a peculiar change in the voltage change and operates the relay means, thereby changing the current limiting resistance of the power supply circuit. It is something that can be switched.

Hereinafter, the present invention will be explained in further detail based on embodiments shown in the drawings.

Reference numeral 1 shown in FIG. 1 is an embodiment of an electrophoretic spectrometer according to the present invention. A terminal liquid electrode tank 3 and a leading liquid electrode tank 4 are connected to both ends of the constant current power supply circuit 2, and a sample injection part 5 is connected between these.
and a detector 6 are connected through a conduit 7 to constitute a basic separation section. The constant current circuit 2 has current limiting resistors R ₀ and R ₁ connected in series, and supplies a constant current by keeping the voltage drop there constant. The pipe line 7 between the sample injection part 5 and the detector 6 is a two-stage tube in which a pretube 7a with a large pipe diameter and a capillary reach tube 7b with a small pipe diameter are connected in series via a stepped part 8. The stepped portion 8 corresponds to a sudden change in pipe diameter.

10 is an A-D converter, which is a power supply circuit 2
The supplied voltage is converted into a digital quantity and outputted to the microcomputer 11. The microcomputer 11 samples the A-D converter 10 at predetermined short intervals based on a built-in clock, and subtracts the value at the previous sampling from the sampled value. The resulting difference value is the time variation of the supply voltage. Therefore, the AD converter 10 and the microcomputer 11 correspond to voltage change measuring means.

The microcomputer 11 further subtracts the difference value obtained by the previous subtraction from the difference value. Then, when the double difference value exceeds a certain limit value, an open signal is given to the relay 12. The contacts of the relay 12 are closed from the start of electrophoresis to the time when the open signal is applied, shorting the current limiting resistor _R1 , but are opened by the open signal. Constant current circuit 2 is a current limiting resistor as described above.
It operates to keep the voltage drop at R ₀ and R ₁ constant, so if the current limiting resistors R ₀ and R ₁ have the same resistance value, when the contacts of relay 12 open, they will be closed. It will now supply a current that is half the value of . For example, if a current of 200 μA is supplied when the contacts of the relay 12 are closed, a current of 100 μA will be supplied after the contacts of the relay 12 are opened. In this way, the microcomputer 11 and the relay 12 correspond to current switching means.

Next, the operating principle of this electrophoretic spectrometer 1 for detecting that a certain ion component zone of a sample passes through a sudden change in pipe diameter will be explained.

For convenience of explanation, it is assumed that the sample consists of only one type of ionic component zone S, as shown in FIG.
It is assumed that the conductivity decreases in the order of leading liquid L → sample → terminal liquid T. Further, although the values handled by the microcomputer 11 are digital quantities, for convenience of explanation, they will be expressed as analog quantities as shown in FIG. That is, the difference value, which is the time change of the supply voltage, is expressed as the first-order differential V' of the supply voltage V, and the double difference value is expressed as the second-order differential V''.This substitution does not bring about any essential change. should be obvious.

Now, when electrophoresis is performed with a constant current, Figure 2a,
Electrophoresis proceeds in the order of b, c, and d. At this time, if the current value is not changed, the supply voltage V changes as shown in FIG. 3A. Here time t ₁
corresponds to the instant in FIG. 2b, and time _t2 corresponds to the instant in FIG. 2c. Therefore, the time variation of the supply voltage V becomes like the first-order differential V' shown in FIG. 3B. Furthermore, the second derivative V'' is as shown in Figure 3 C. Therefore, if a limit value α is set for the value of the second derivative V'', times t ₁ and t ₂ can be detected extremely easily. .

Although not limited to the examples shown in FIGS. 2 and 3, interfaces between different ionic component zones can be When passing through a sudden change in pipe diameter, the supply voltage always shows a peculiar change. In other words, the change in supply voltage is a steady change when one ionic component zone is passing through. Therefore, by measuring the temporal change in the supply voltage, the passage of any ionic component zone can be detected.

Returning to FIG. 3C, if the conductivity of the ionic component zone S is close to that of the leading liquid L and does not cause any particular problem within the capillary reach tube 7b, the current is switched at time _t2 . By programming the microcomputer 11 in such a manner, the above-mentioned disadvantages caused by the low conductivity of the terminal liquid T can be prevented. Furthermore, if the conductivity of the ionic component zone S is so small that it becomes a problem, the current may be programmed to be switched at time _t1 .

In this way, according to this electrophoretic spectrometer 1,
Since it is possible to accurately and easily know that each zone to be electrophoresed passes through the stepped portion 8, and thereby to switch to the optimum current value at the optimum timing, extremely suitable electrophoresis can be performed. It is possible to do a folding. Moreover, the configuration is relatively easy.

As another modification of the electrophoretic spectrometer of the present invention, the pipe diameter abruptly changes into a constriction 13 shown in FIG.
For example, it may be formed into a bulge portion 14 or a bulged portion 14 shown in FIG.

Another example is one in which the voltage change measuring means is an analog differential circuit.

Further, as an application example, there is a system in which passing through a predetermined ion component zone is detected and automatically activates some kind of separation means, or as shown in FIG. Electrophoresis is performed with a large constant current in a tube 17 with a large pipe diameter between the first leading liquid electrode tank 16 and a predetermined ion component zone is detected when it comes to a sudden change in pipe diameter section 18. One example is one in which the power supply circuit is switched and electrophoresis is performed between the terminal liquid electrode tank 15 and the second leading liquid electrode tank 19 using a capillary reach tube 20. Here, 21 is a sample injection section, and 22 is a detector.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the configuration of an embodiment of the electrophoretic spectrometer of the present invention, FIG. 2 is an explanatory diagram of the progress of electrophoresis, and FIG. 3A is a diagram showing temporal changes in supply voltage.
B is a diagram showing the temporal change of the first derivative, C is a diagram further showing the temporal change of the second derivative, FIGS. 4 and 5 are diagrams showing an example of the configuration of the pipe diameter sudden change section, and FIG.
The figure is an explanatory diagram of a main part of an application example of an electrophoretic spectrometer according to the present invention. 1... Electrophoresis spectrometer, 2... Constant current power supply circuit,
3...Terminal liquid electrode tank, 4...Leading liquid electrode tank, 5...Sample injection part, 6...Detector, 7...Pipe line,
8... Stepped portion, 10... A-D converter, 11... Microcomputer, 12... Relay, R ₀ , R ₁ ...
Current limiting resistor, 13... constriction, 14... bulge.

Claims (1)

[Scope of Claims] 1. An electrophoresis analyzer in which a sample injection part and a detector are sequentially connected by a pipe between a terminal liquid electrode tank and a leading liquid electrode tank, which are respectively connected to both ends of a constant current power supply circuit. Electrophoretic spectrometry, characterized in that a pipe diameter abruptly changing part is formed in the pipe line between the sample injection part and the detector, and a voltage change measuring means for measuring temporal changes in the supplied voltage is connected to the power supply circuit. Device. 2. The electrophoretic spectrometer according to claim 1, wherein the sudden change in pipe diameter is a constriction where the pipe diameter becomes smaller at that position. 3. The electrophoretic spectrometer according to claim 1, wherein the sudden change in pipe diameter is a bulge in which the pipe diameter increases at that position. 4 The pipe line between the sample injection part and the detector is a two-stage tube in which a pretube with a large pipe diameter and a capillary reach tube with a small pipe diameter are connected in series via a stepped part, and the pipe diameter suddenly changes. 2. The electrophoretic spectrometer according to claim 1, wherein the stepped portion is the stepped portion. 5. In an electrophoretic spectrometer in which a sample injection part and a detector are connected in order by a pipe between a terminal liquid electrode tank and a leading liquid electrode tank connected to both ends of a constant current power supply circuit, respectively, the sample injection part A sudden change in pipe diameter section is formed in the pipe line between the Electrophoretic analysis characterized by comprising current switching means for detecting a peculiar change in the output of the voltage change measuring means that occurs when a surface passes and switches the current value of the constant current supplied from the power supply circuit. Device.