Flow cell for long-optical-path colorimetry, long-optical-path colorimetry device and long-optical-path colorimetry method

Abstract

The invention discloses a flow cell for long-optical-path colorimetry, a long-optical-path colorimetry device and a long-optical-path colorimetry method. The discharge of bubbles can be realized under the condition that an additional mechanical subsystem or a vacuum device is not added. Specifically, when bubbles exist in the liquid to be detected, the bubbles are attached to the top of the cavity or discharged from the third channel under the action of buoyancy, or the bubbles seep out through the tube wall of the liquid core waveguide tube under the pressure of the injection pump. Due to the extremely low influence of the bubbles on the light path in the condition, scattering and absorption errors caused by the bubbles are reduced, and the sensitivity and accuracy of long-optical-path colorimetry are remarkably improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of photoelectric analysis, and particularly relates to a flow cell for long optical path colorimetry, a long optical path colorimetry device and a long optical path colorimetry method. BACKGROUND

[0002] Long optical path colorimetry significantly improves the sensitivity of spectral signals by extending the effective optical path, and a liquid-core waveguide is an important means to realize long optical path colorimetry and device miniaturization at the same time. However, this technology always faces a key problem in practical application: bubble interference. Whether it is a microbubble of dissolved gas in the liquid or a bubble entrained in the sampling process, these bubbles are easily attached to the cell wall of the flow cell. These bubbles seriously interfere with the signal light through scattering and absorption, which leads to a series of problems such as unstable detection baseline, increased noise, and decreased accuracy, and ultimately may even lead to detection failure.

[0003] CN217033579U discloses a flow cell colorimetry device capable of removing bubbles. This scheme makes the whole flow cell rotate and vibrate through a set of complex bearing, rotating seat, spring and high-frequency vibrator structure, so as to "shake off" or "vibrate off" the bubbles out of the light path. This scheme is complex and bulky, and the additional mechanical structure adjustment mechanism occupies a lot of space, making it difficult to realize miniaturization and integration of the entire detection device; the presence of movable parts increases the failure rate, processing difficulty and manufacturing cost of the system; and usually requires manual intervention or complex control program to trigger the bubble removal action, which cannot achieve continuous and passive bubble management during detection.

[0004] CN110398459A discloses a long optical path liquid flow cell and a bubble removal detection method. This scheme places the entire liquid-core waveguide in a vacuum container, and uses the gas permeability of the liquid-core waveguide material to "extract" the bubbles attached to the inner wall of the tube under the action of the vacuum negative pressure outside the tube. Although this scheme has good bubble removal effect, it must be equipped with a vacuum container, a vacuum air pump and a precise sealing structure to ensure the air tightness of the system, which increases the cost, energy consumption, volume and maintenance difficulty of the device. SUMMARY

[0005] The purpose of the present application is to provide a flow cell for long optical path colorimetry, a long optical path colorimetry device and a long optical path colorimetry method. This scheme can significantly reduce the influence of bubbles on the system without additional complex systems, and can improve the colorimetry accuracy while having the advantages of simple structure, high automation and low manufacturing cost.

[0006] The technical scheme of the present application is as follows:

[0007] A long optical path flow cell for colorimetry, a cavity is formed in the shell of the flow cell, and a first channel, a second channel and a third channel are respectively connected with the shell and the outside;

[0008] The first channel is used for installing a light source or a photocell to receive or emit signal light; the third channel is a liquid inlet or a liquid outlet; and the second channel is used for communicating with a liquid core waveguide tube to transmit a to-be-tested liquid and signal light;

[0009] The first channel, the cavity and the second channel are coaxially arranged, the third channel is not parallel to the first channel, the communication position of the cavity and the second channel is lower than the connection position of the cavity and the first channel, and the communication position of the cavity and the second channel is not higher than the communication position of the cavity and the third channel.

[0010] In some preferred embodiments, the highest point of the inner wall of the cavity is higher than the connection position of the cavity and the first channel and the second channel.

[0011] In some preferred embodiments, the top of the cavity has a dome-shaped protrusion.

[0012] In some preferred embodiments, the main body of the cavity is spherical. In other possible implementations, the main body of the cavity can also be in the shape of an olive, an ellipsoid or the like, which is an intermediate bulge and a shrinkage at both ends, and the cavity with a streamline-shaped inner wall can guide the movement of bubbles. Alternatively, the cavity can also be in any solid structure such as a cuboid.

[0013] A long optical path colorimetric device includes two flow cells described above, the two second channels of the two flow cells are connected through a liquid core waveguide tube, the flow cell with a higher installation position is a high-position flow cell, and the flow cell with a lower installation position is a low-position flow cell;

[0014] The first channel of the low-position flow cell is installed with a light source, the third channel of the low-position flow cell is connected with a syringe pump, and the first channel of the high-position flow cell is installed with a photocell.

[0015] The to-be-tested liquid is pumped out by the syringe pump, sequentially flows through the third channel, the cavity and the second channel of the low-position flow cell, then enters the second channel of the high-position flow cell through the liquid core waveguide tube, and finally flows through the cavity and the third channel of the high-position flow cell and flows out of the colorimetric device;

[0016] The signal light is emitted by the light source, sequentially passes through the first channel, the cavity and the second channel of the low-position flow cell, then enters the second channel of the high-position flow cell through the liquid core waveguide tube, and finally passes through the cavity and the first channel of the high-position flow cell to transmit the signal light to the photocell;

[0017] When there is a bubble in the to-be-tested liquid, the bubble adheres to the top of the cavity or is discharged from the third channel under the action of buoyancy, or the bubble seeps out through the wall of the liquid core waveguide tube under the pressure of the syringe pump.

[0018] A long optical path colorimetric method is based on the long optical path colorimetric device.

[0019] In some preferred embodiments, the long optical path colorimetric method comprises the following steps: first, the to-be-tested liquid is injected into the long optical path colorimetric device through an externally connected injection pump; after the long optical path colorimetric device is filled with the to-be-tested liquid, the light source is turned on to emit signal light; finally, the photovoltaic cell receives the signal light and converts it into an electric signal, and the detection is completed.

[0020] In some preferred embodiments, before the to-be-tested liquid is injected into the long optical path colorimetric device for detection, the long optical path colorimetric device is sequentially washed with water and the to-be-tested liquid.

[0021] The present application has at least the following beneficial effects:

[0022] 1. When there are bubbles in the to-be-tested liquid, the bubbles located in the flow cell adhere to the top of the cavity or are discharged from the third channel under the action of buoyancy, and the bubbles located in the liquid-core waveguide tube seep out of the liquid-core waveguide tube under the pressure of the injection pump. Through the above arrangement, the present application significantly reduces the influence of bubbles on the light path, thereby effectively reducing the error caused by bubble scattering and absorbing signal light, and improving the sensitivity and accuracy of the long optical path colorimetry.

[0023] 2. The present application cooperatively designs the high-low flow cell layout and the specific cavity structure, automatically guides and captures the bubbles in the area outside the light path by using the buoyancy and flow power of the fluid itself. This scheme abandons the traditional active bubble removal mode which relies on complex external systems such as vacuum pumps, vibrators or rotating mechanisms, and simplifies the device structure while achieving efficient bubble removal, thereby reducing the manufacturing cost and volume, and being conducive to the miniaturization and portability of the device. In addition, since there is no complex mechanical structure or vacuum device inside the device, the risk of failure and performance decline caused by mechanical wear, aging and vacuum seal failure can be effectively reduced, thereby improving the reliability and measurement stability of the device. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 It is a structural schematic diagram (front view) of the flow cell in Example 1;

[0025] Figure 2 It is a structural schematic diagram (front view) of the long optical path colorimetric device in Example 1;

[0026] Figure 3 It is a structural schematic diagram (front view) of the long optical path colorimetric device in Example 2.

[0027] Reference numerals in the figure: 1-flow cell; 11-cavity; 12-first channel; 13-second channel; 14-third channel; 2-liquid-core waveguide. DETAILED DESCRIPTION

[0028] The technical solutions of the present application will be further described and explained by the specific embodiments.

[0029] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are the preferred embodiments of the present application, and should not be regarded as exclusive to other embodiments. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0030] In the claims, specification, and above drawings of the present application, unless otherwise expressly defined, the orientation words such as "top", "bottom", "inner", "outer", "upper", "lower", "front", "back", etc. indicate the orientation or positional relationship based on the orientation and position relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation or be constructed and operated in a particular orientation, so it cannot be understood as limiting the specific protection scope of the present application.

[0031] Embodiment 1

[0032] This embodiment first provides a long optical path colorimetric flow cell, the structure of which is shown in Figure 1 The cavity 11 and the first channel 12, the second channel 13 and the third channel 14 which respectively communicate with the shell and the outside are formed in the shell of the flow cell 1. The main body of the cavity 11 is spherical, and the top has a dome-shaped protrusion.

[0033] The first channel 12 is used to install a light source or a photocell (not shown in the figure); the second channel 13 is used to communicate with the liquid-core waveguide 2, and the third channel 14 is a liquid inlet or a liquid outlet. The first channel 12, the cavity and the second channel 13 are coaxially arranged, and the third channel 14 is perpendicular to the first channel 12. The communication part of the cavity 11 and the second channel 13 is lower than the connection part of the cavity 11 and the first channel 12, and the communication part of the cavity 11 and the second channel 13 is not higher than the communication part of the cavity 11 and the third channel 14. The highest point of the inner wall of the cavity 11 is higher than the connection part of the cavity 11 and the first channel 12 and the second channel 13 (i.e. the optical path axis).

[0034] Further, this embodiment provides a long optical path colorimetric device comprising two above-mentioned flow cells and a detection method based on the device.

[0035] As shown in Figure 2As shown, the two flow cells of the long optical path colorimetric device are a low-position flow cell and a high-position flow cell, and the second channels 13 of the two flow cells are communicated through the liquid core waveguide tube 2, and the installation position of the low-position flow cell is lower than that of the high-position flow cell.

[0036] The first channel 12 of the low-position flow cell is installed with a light source, and the third channel 14 thereof is communicated with the injection pump; the first channel 12 of the high-position flow cell is installed with a photocell, and the third channel 14 thereof serves as a liquid outlet; and the second channels 13 of the two flow cells are communicated through the liquid core waveguide tube 2. In the embodiment, the light source and the photocell are respectively screwed with the first channel 12, facilitating subsequent disassembly and maintenance.

[0037] Further, it can be seen that in the low-position flow cell, the connection between the cavity 11 and the third channel 14 is close to the highest point of the cavity 11, and after the to-be-tested liquid enters the cavity 11 from the third channel 14, this arrangement can guide the bubbles to gather at the top of the cavity 11 under the action of the buoyancy. Meanwhile, the third channel 14 is located above the optical axis, which can further reduce the influence of the bubbles in the to-be-tested liquid entering the device from the third channel 14 on the optical path.

[0038] The material of the liquid core waveguide tube 2 is Teflon, and when there are a small amount of bubbles in the liquid core waveguide tube 2, these bubbles will seep out from the tube wall of the liquid core waveguide tube 2 under the action of the hydraulic pressure generated after the injection pump injects the to-be-tested liquid.

[0039] In the high-position flow cell, the second channel 13 is parallel to the first channel 12, and the cavity 11 is connected with the third channel 14 at the highest point at the top thereof, and this arrangement can guide the bubbles in the cavity 11 to float up and be discharged out of the device through the third channel 14. In this process, the moving path of the bubbles is all above the optical axis, and will not affect the detection result.

[0040] During detection, first, the water is passed into the device through the injection pump for cleaning, and then the to-be-tested liquid is injected for wetting; then new to-be-tested liquid is injected into the device again, and after the device is filled with the to-be-tested liquid, the light source is turned on; finally, the photocell receives the signal light and converts it into an electric signal, and the detection is completed.

[0041] In this process, the to-be-tested liquid is pumped out by the injection pump, sequentially flows through the third channel 14, the cavity 11 and the second channel 13 of the low-position flow cell, enters the second channel 13 of the high-position flow cell through the liquid core waveguide tube 2, and finally flows through the cavity 11 and the third channel 14 of the high-position flow cell and flows out of the device. The signal light is emitted by the light source, sequentially passes through the first channel 12, the cavity 11 and the second channel 13 of the low-position flow cell, enters the second channel 13 of the high-position flow cell through the liquid core waveguide tube 2, and finally passes through the cavity 11 and the first channel 12 of the high-position flow cell and is received by the photocell.

[0042] In the above process, most of the bubbles in the flow cell and attached to the liquid core waveguide 2 enter the high flow cell from the liquid core waveguide 2 under the action of buoyancy and the thrust of the liquid to be tested, and are discharged from the third channel 14 of the high flow cell to the device, thereby reducing or even avoiding the influence on the light path. Even if part of the bubbles adhere to the inner wall of the cavity 11 under the action of buoyancy, their attachment position is higher than the axis of the light path and will not affect the light path. Therefore, the long optical path colorimetric cell device can effectively avoid the interference of bubbles on the light signal, thereby improving the detection accuracy.

[0043] Example 2

[0044] The difference between Example 2 and Example 1 is that the liquid core waveguide 2 increases the length (optical path) by winding, thereby further improving the detection accuracy.

[0045] The above is only a preferred embodiment of the present application, and therefore cannot limit the scope of the present application. Any equivalent changes and modifications made in accordance with the scope of the present application and the content of the specification should still be within the scope of the present application.

Claims

1. A flow cell for long optical path colorimetry, characterized in that, The flow cell has a cavity inside its shell and a first channel, a second channel, and a third channel that respectively connect the shell to the outside. The first channel is used to install a light source or photocell to receive or emit signal light; the third channel is a liquid inlet or liquid outlet; the second channel is used to connect with the liquid core waveguide to transmit the liquid to be tested and the signal light. The first channel, the cavity, and the second channel are coaxially arranged. The third channel is not parallel to the first channel. The connection between the cavity and the second channel is lower than the connection between the cavity and the first channel, and the connection between the cavity and the second channel is not higher than the connection between the cavity and the third channel.

2. The flow-through pool as described in claim 1, characterized in that, The highest point of the inner wall of the cavity is higher than the connection between the cavity and the first channel and the second channel.

3. The flow-through pool as described in claim 1 or 2, characterized in that, The top of the cavity has a dome-shaped protrusion.

4. A long optical path colorimetric device, characterized in that, Includes the flow pools of any one of claims 1 to 3; The two second channels of the two flow cells are connected by a liquid core waveguide. The flow cell with a higher installation position is the high-level flow cell, and the flow cell with a lower installation position is the low-level flow cell. The first channel of the low-level flow cell is equipped with a light source, the third channel of the low-level flow cell is connected to the injection pump, and the first channel of the high-level flow cell is equipped with a photocell. The liquid to be tested is pumped out by the injection pump, flows sequentially through the third channel, the cavity and the second channel of the low-level flow cell, then enters the second channel of the high-level flow cell through the liquid core waveguide, and finally flows through the cavity and the third channel of the high-level flow cell and out of the colorimetric device; The signal light is emitted by the light source, passes sequentially through the first channel, the cavity, and the second channel of the low-level flow cell, then enters the second channel of the high-level flow cell through the liquid core waveguide, and finally passes through the cavity and the first channel of the high-level flow cell to transmit the signal light to the photovoltaic cell. When air bubbles are present in the liquid to be tested, the air bubbles adhere to the top of the cavity or are discharged from the third channel under the action of buoyancy, or the air bubbles seep out through the tube wall of the liquid core waveguide under the pressure of the injection pump.

5. A long optical path colorimetric method, characterized in that, Based on the long optical path colorimetric device described in claim 4.

6. The long optical path colorimetric method as described in claim 5, characterized in that, The process includes the following steps: First, the liquid to be tested is injected into the long optical path colorimetric device through an external injection pump. After the long optical path colorimetric device is filled with the liquid to be tested, the light source is turned on to emit signal light. Finally, the photocell receives the signal light and converts it into an electrical signal to complete the detection.

7. The long optical path colorimetric method as described in claim 6, characterized in that, Before injecting the liquid to be tested into the long optical path colorimetric device for detection, the long optical path colorimetric device is first washed with water and the liquid to be tested in sequence.

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