JPH04136563U - Detection unit for capillary electrophoresis device - Google Patents

Abstract

(57) [Summary] [Purpose] The purpose is to provide a detection section that achieves ultrahigh sensitivity while maintaining high resolution in a capillary electrophoresis device. [Structure] This is achieved by installing a capillary 1 that is a thin tube with a circular cross section, a flow cell 5 that has a rectangular cross section with a longer side than the thin tube, and a connecting portion 3 that smoothly connects the two. [Effect] The use of a thin capillary with a circular cross section provides high resolution, and the smooth connection to a rectangular cross-section flow cell with a long optical path length provides the effect of high resolution and high sensitivity detection.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

This invention relates to a detector for a capillary electrophoresis device, especially when a flow cell is installed. , by smoothly connecting the flow cell to the capillary, the capillary Detects separated components with ultra-high sensitivity without deteriorating the high separation state that is a feature of electrophoresis. The present invention relates to providing a detecting unit capable of detecting

0002

[Conventional technology]

Capillary electrophoresis equipment is a method for separating and detecting components in liquids at high speed and with high resolution. Analytical Chemistry, 62 (1990) No. Pages 403R to 414R (Analytical Chemistry 62 (1990) pp403 It has been described in many reviews and papers, including R~414R). Inspection of this equipment Regarding the method of extraction, the liquid cream disclosed in U.S. Pat. No. 4,375,163 (1983) is used. By repurposing the on-column detection method for romatographs, a reinforcement layer such as polyimide is used. A separation capillary whose outer surface is coated with a used silica tube was inspected with some of the coating layer removed. A method of irradiating light with light is generally adopted. In contrast, analytical Chemistry, 62 (1990), pp. 2149-2152 (Analytical Chemistry 62 (1990) pp2149-2152) , a single uncoated glass capillary with a rectangular cross section is used for both the separation section and the detection section. A method has also been proposed.

0003

[Problem that the idea aims to solve]

U.S. Pat. No. 4,375,163 discloses a liquid chromatograph separation section coated with a reinforcing layer. A surface capillary is used, and the detection section uses a capillary with the reinforcing layer removed. A cross-sectional view in which the detection light passes perpendicularly is disclosed. However, as the sample passes The optical path length inside the capillary, that is, the capillary inner diameter is 500 μm or less, Detection limits for trace samples and detection sensitivity for high-precision measurements are not taken into account. not present. Furthermore, in capillary electrophoresis, a high voltage is applied across the capillary. In order to prevent the separation performance from decreasing inside the capillary due to the Joule heat generated by Since capillaries of 100 μm or less are generally used, short optical path lengths are sensitive. There was a problem in terms of performance that was very disadvantageous. On the other hand, using a capillary with a rectangular cross section Products with internal dimensions of 50 μm x 1000 μm are commercially available, and the optical path length is It is effective for high-sensitivity detection because it can measure up to 1000 μm, but the rectangular tube makes it difficult to inject the sample. The method is complicated, and the Joule heat increases as the cross-sectional area increases and heat is released from the rectangular tube. The problem is that it is not possible to obtain high resolution as with circular cross-section capillaries due to poor was there. Using the same capillary for the separation section and the detection section in this way will improve the separation performance. There was a major problem in that the sensitivities were contradictory.

0004 The purpose of this invention is to use a capillary that uses a much thinner tube than a liquid chromatograph. - In an electrophoresis device, a circular cross-section capillary is used as the separation section, and a rectangular cross-section flow By using a cell as the detection part and smoothly connecting the two, high resolution and The object of the present invention is to provide an ultra-high sensitivity capillary electrophoresis device.

[0005]

[Means to solve the problem]

The above purpose is to create a circular cross-section capillary with high mechanical strength, and to reduce the number of uncovered parts on the outer surface. A rectangular cross-section flow cell with a capillary -Achieved by installing it in an electrophoresis device.

[0006]

[Effect]

A sample injected into a capillary is exposed to a high voltage applied across the capillary. is separated into each component based on the principle of electrophoresis, and passes through the flow cell of the detection section. Ru. At this time, a capillary with a circular cross section and a flow cell with a rectangular cross section are connected in a tapered manner. By connecting smoothly at the end, a circular cross-section capillary with an inner diameter of 100 μm or less can be connected. Each component of the sample is separated with high performance using a high number of theoretical plates, and the flow cell flows into. In addition, the flow cell has a rectangular cross section, and the optical path length is determined by the inner diameter of the capillary. The flow cell surface is flat, so the flow cell surface of the incident light is reduced by several times to several thousand times. Because there is little scattering on the optical surface, detection is possible with ultrahigh sensitivity. This invention uses absorption type detection. It can be applied not only to fluorescent detectors but also to fluorescent detectors, and can also be applied to increase the sensitivity of fluorescence. It is self-evident.

[0007]

【Example】

Figure 1 shows an implementation of the detection section including the flow cell and capillary connection section according to the present invention. Give an example. The detecting section of the present invention includes a capillary 1, a connecting section 3, and the connecting section 3 and the capillary. A connecting surface 2 of the pillar 1, a flow cell 5, a connecting surface 4 of the flow cell 5 and the connecting portion 3, It consists of an outflow part 6 from the flow cell 5, an incident light 9 for detection, and an output light 10 for detection. However, a sample inflow direction 7 and a sample outflow direction 8 are also shown for explanation of the operation. Kya Pillary 1 includes a fused silica capillary, a fluororesin capillary, etc. Analytical Chemistry, 62 (1990) No. Cut the borosilicate glass capillary described on pages 2149 to 2152. I cut it off and used it. Connection part 3 and connection surface 2 of capillary 1, and connection with flow cell 5 The connection surface 4 of the part 3 is connected by melting in the case of a fused silica capillary. Ta. The detection unit manufactured in this way is incorporated into the detector of the capillary electrophoresis device. In rare cases, it works like this: That is, separated by electrophoresis in capillary 1 Sample components are introduced from the sample inflow direction 7 through the connection surface 2 into the connection part 3 . There So, the flow path part of the connection part 3 has a smooth shape against the flow, such as a tapered shape. Because of this, the separated components can be connected without disturbing the high resolution obtained with capillary 1. reaches the surface 4, flows into the flow cell 5 and drains from the outlet 6 of the flow cell 5. flows into the side electrode layer. While the separated components are present inside the flow cell 5, the flow The incident light 9 irradiating the cell 5 causes the optical path length in the long side direction of the flow cell 5 to be measured. The amount of attenuated light corresponding to the material component is detected as the emitted light 10. The flow path after optical detection is In the example, a rectangular cross-section capillary was used, but the same structure as the flow cell inlet side was used. There is no problem with using a circular cross-section capillary. In addition, in this example, the absorption detection method However, the present invention can be applied not only to absorption type detectors but also to fluorescence type detectors. Furthermore, although capillary zone electrophoresis was described here, gel-filled capacitors It can also be applied to other separation modes of electrophoresis such as pillar electrophoresis.

[0008] Therefore, according to this embodiment, the tapered connecting portion 3 is connected to the capillary 1 and the flow cell. By providing between Sample components can be smoothly introduced into a flow cell with a long optical path length, allowing high This has the effect of providing a detection unit capable of ultra-high sensitivity detection while maintaining separation ability.

[0009] FIG. 2 shows a comparative example of electropherograms using two types of capillaries. In (a), a polyimide-coated circular cross-section capillary is used in the separation part, and the capillary is used in the detection part. Conventional example using Lee's polyimide peeling part, (b) is a circular polyimide coated part on the separating part. Cut section of the rectangular section borosilicate glass capillary into the detection section. This is an example of the present invention using. The circular cross-section capillary has an inner diameter of 50 μm, and the rectangular A shaped cross-section capillary with internal dimensions of 50 μm×300 μm was used. capillary -The electrophoresis device is a capillary electrophoresis system P/ACE system manufactured by Beckman. The detection part of the system 2000 was modified and used for the experiment. As for the measurement conditions, the buffer solution is Using 0.1M phosphate, pH 2.5, the sample contained albumin and fibrinogen. A mixed solution (concentration: 10 μM each) was used. In addition, the separation capillary has an inner diameter of 50 μm x execution length (length from sample injection part to detector) 50cm, electric field strength 200V /cm, and the detector is ultraviolet absorption detection with a wavelength of 200 nm. The number of theoretical plates is (a) (b) Both have about 1 million steps, which is a circular cross section that cannot be obtained with a rectangular cross section capillary. This is the high resolution characteristic of surface capillaries. What should be noted here is shown in (b). The present invention is able to achieve higher detection sensitivity than the conventional method (a).

0010

[Effect of the idea]

According to the present invention, a capillary with a circular cross section is used in the separation section, and the capillary is further By using a flow cell with a rectangular cross section with longer sides as the detection part, the two can be connected smoothly. As a result, we can provide detection units for capillary electrophoresis devices with high resolution and ultra-high sensitivity. It has the effect of

[Brief explanation of drawings]

FIG. 1 is a diagram showing a connection between a flow cell and a capillary.

FIG. 2 is a diagram showing a comparison of electropherograms.

[Explanation of symbols]

1... Capillary, 3... Connection part, 5... Flow cell, 6...
Outflow portion, 9...incident light, 10...outgoing light.

Claims (6)

[Scope of utility model registration request] Claims 1: A container containing a sample, a capillary for electrophoresing the sample, a mechanism for injecting the sample into one end of the capillary, two reservoirs holding a solution installed at both ends of the capillary, and a capillary for electrophoresing the sample. In a capillary electrophoresis apparatus, which includes application electrodes each immersed in a solution in a reservoir, a high voltage power supply that applies a voltage between the application electrodes, and a detector that detects a sample separated by the capillary, the detector 1. A detection unit for a capillary electrophoresis device, characterized in that a flow cell and a connecting portion between the flow cell and the capillary are provided inside. 2. A container containing a sample, a capillary for electrophoresing the sample, a mechanism for injecting the sample into one end of the capillary, two reservoirs holding a solution installed at both ends of the capillary, and the two reservoirs. In a capillary electrophoresis apparatus, which includes application electrodes each immersed in a solution in a reservoir, a high voltage power supply that applies a voltage between the application electrodes, and a detector that detects a sample separated by the capillary, the detector 1. A detection section for a capillary electrophoresis device, comprising a flow cell having a transparent member inside, and a tapered connection section connecting the flow cell and the capillary. 3. The flow cell is for an absorption type detector, and the cross-sectional shape of the flow cell including the optical axis of the detection light passing through the flow cell and perpendicular to the flow path is rectangular, and in the cross section, the cross section of the flow path portion is rectangular. The length of the long side is 100 μm or more 300
The detection unit for a capillary electrophoresis device according to claim 1 or 2, characterized in that the diameter is 0 μm or less. 4. The flow cell is for a fluorescence detector, and the cross-sectional shape of the flow cell including the optical axis of excitation light incident on the flow cell and perpendicular to the flow path is rectangular, and in the cross section, the cross section of the flow path portion is rectangular. The length of the long side is 100 μm or more 300
The detection unit for a capillary electrophoresis device according to claim 1 or 2, characterized in that the diameter is 0 μm or less. 5. The material of the flow cell is quartz or glass, and the wavelength is from 195 nm to 350 nm, or 220 nm.
5. The detection section for a capillary electrophoresis device according to claim 1, wherein the detection section for a capillary electrophoresis device has extremely low absorption of light in the range from m to 730 nm. 6. The electrical capillary according to claim 1, wherein the capillary is a quartz capillary whose outer surface is provided with a protective layer to ensure mechanical strength, or a fluororesin capillary. Detection unit for electrophoresis device.