Flow cell for detecting nitrate

Abstract

The utility model provides a kind of for detecting nitrate flow cell, comprising: flow cell body;The liquid flow passage of the flow cell body is penetrated, the liquid flow passage includes the liquid inlet, the detection flow passage of straight line type and the liquid outlet that are sequentially connected;Lamp bead and photodiode component are respectively located at the detection flow passage both ends, LED chip and photodiode chip are encapsulated in the lamp bead.This utility model simultaneously encapsulates LED chip and photodiode chip in lamp bead, so that when detecting liquid absorbance, the initial absorbance of liquid detected by photodiode component can be corrected according to the luminous intensity of LED chip detected by photodiode chip, so as to ensure the accuracy of nitrate detection;Moreover, the structure of flow cell is relatively simple and has high integration, can have smaller equipment volume, be convenient for being connected with other detection equipment, and has lower production and detection cost.

Description

Technical Field

[0001] This utility model relates to the field of nitrate detection technology, specifically to a flow cell for detecting nitrate. Background Technology

[0002] Nitrate detection, a crucial step in total nitrogen analysis, is vital for safeguarding public health and environmental safety. Excessive nitrate contamination of drinking water or food can cause methemoglobinemia, endangering life. Furthermore, excessive nitrate is a major contributor to eutrophication, leading to algal blooms, ecological imbalance, and water quality deterioration. Therefore, nitrate content in water is a critical indicator for assessing drinking water safety, monitoring agricultural pollution, and evaluating the effectiveness of environmental remediation. Spectrophotometry provides a highly efficient and accurate method for quantitatively analyzing nitrate concentration. Most existing nitrate detection devices utilize LED light sources and photodiodes on either side of the liquid channel to detect absorbance, thus determining nitrate content. However, LED light sources often suffer from unstable luminous intensity due to factors such as operating temperature, current intensity, and lifespan, resulting in poor accuracy in nitrate detection. Moreover, traditional nitrate detection devices are typically complex and bulky, unsuitable for integration into other detection processes, and can only be used independently, leading to high detection and production costs. Utility Model Content

[0003] To solve the above-mentioned technical problems, this utility model provides a flow cell for detecting nitrates. By simultaneously encapsulating an LED chip and a photodiode chip inside the lamp bead, the light intensity of the LED chip detected by the photodiode chip can be corrected when detecting the absorbance of the liquid, thereby ensuring the accuracy of nitrate detection. Moreover, the flow cell has a relatively simple structure and high integration, resulting in a small device size, which is convenient for connection with other detection devices, and the production and testing costs are low.

[0004] The technical solution adopted in this utility model is as follows:

[0005] An embodiment of this utility model provides a flow cell for detecting nitrates, comprising: a flow cell body; a liquid flow channel penetrating the flow cell body, the liquid flow channel including an inlet, a linear detection channel, and an outlet connected in sequence; and LED beads and photodiode assemblies located at both ends of the detection channel, wherein the LED beads encapsulate an LED chip and a photodiode chip, the photodiode chip is used to detect the luminous intensity of the LED chip, and the photodiode assembly is used to detect the initial absorbance of the liquid in the detection channel.

[0006] In addition, the flow cell proposed according to this utility model may also have the following additional technical features:

[0007] According to one embodiment of the present invention, the flow cell body is an integral structure, and two mounting slots are provided inside the flow cell body. The two mounting slots are respectively used to install the lamp beads and the photodiode assembly.

[0008] According to one embodiment of the present invention, the emission wavelength of the LED chip is 220±10nm.

[0009] According to one embodiment of the present invention, the LED chip and the photodiode chip are mounted on a ceramic substrate.

[0010] According to one embodiment of the present invention, the lamp bead further includes a hemispherical focusing lens, which is used to focus light onto the LED chip.

[0011] According to one embodiment of the present invention, the focusing center of the focusing lens, the center line of the detection channel, and the absorbance detection center of the photodiode assembly are located on the same straight line.

[0012] According to one embodiment of the present invention, the liquid flow channel is a Z-shaped flow channel, and the liquid inlet and the liquid outlet are located at the inlet and outlet of the Z-shaped flow channel, respectively.

[0013] According to one embodiment of the present invention, the liquid inlet is provided with an internal thread, which mates with a Peek connector inserted into the liquid inlet.

[0014] According to one embodiment of the present invention, a data processing unit is further included. The data processing unit is electrically connected to the photodiode chip and the photodiode assembly, respectively. The data processing unit is used to correct the initial absorbance detected by the photodiode assembly based on the current luminous intensity of the LED chip currently detected by the photodiode chip and the initial luminous intensity of the LED chip detected at the start of nitrate detection.

[0015] The beneficial effects of this utility model are:

[0016] This invention relates to a flow cell for nitrate detection. By encapsulating an LED chip and a photodiode chip within an LED bead at one end of the detection channel, the photodiode chip detects the luminous intensity of the LED chip during nitrate detection. This allows for correction of the initial absorbance detected by the photodiode assembly based on the current and initial luminous intensities of the LED chip detected by the photodiode chip during liquid absorbance analysis. This prevents unstable luminous intensity of the LED chip from affecting the detection results of the photodiode assembly, ensuring the accuracy of nitrate detection. Furthermore, the flow cell has a simple structure and high integration, resulting in a small device size, low production cost, and easy connection to other detection equipment, simplifying the detection process and reducing detection costs. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the flow cell structure according to an embodiment of the present invention;

[0018] Figure 2 for Figure 1 A cross-sectional view of the flow cell shown.

[0019] Figure 3 This is a schematic diagram of the structure of the lamp bead in an embodiment of the present utility model;

[0020] Figure 4 This is a rear view of a lamp bead according to an embodiment of the present invention;

[0021] Figure 5 This is a side view of a lamp bead according to an embodiment of the present invention.

[0022] Figure label:

[0023] 1. Flow cell body; 11. Mounting slot; 2. Liquid flow channel; 21. Liquid inlet; 22. Detection flow channel; 23. Liquid outlet; 3. Lamp bead; 31. LED chip; 32. Photodiode chip; 33. Ceramic substrate; 34. Metal contact; 35. Condensing lens; 4. Photodiode assembly. Detailed Implementation

[0024] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0025] like Figures 1 to 3As shown, the flow cell for detecting nitrates according to an embodiment of the present invention includes a flow cell body 1, a liquid flow channel 2, an LED bead 3, and a photodiode assembly 4. The liquid flow channel 2 penetrates the flow cell body 1 and includes an inlet 21, a linear detection flow channel 22, and an outlet 23 connected in sequence. The LED bead 3 and the photodiode assembly 4 are located at opposite ends of the detection flow channel 22. The LED bead 3 encapsulates an LED chip 31 and a photodiode chip 32. The photodiode chip 32 is used to detect the luminous intensity of the LED chip 31, and the photodiode assembly 4 is used to detect the initial absorbance of the liquid in the detection flow channel 22.

[0026] It is understood that the photodiode assembly 4 may include a photodiode, an operational amplifier circuit, and a microcontroller that are electrically connected to each other. After receiving the light source, the photodiode can convert the received light signal into an electrical signal, which is then amplified by the operational amplifier circuit and input into the microcontroller. This allows the initial light intensity of the light source and the light intensity after absorption by the liquid to be obtained. The microcontroller then calculates the initial absorbance of the liquid in the detection channel 22. The photodiode may be a silicon photodiode of model Hamamatsu S1226-18BQ, or other models of photodiodes may be selected according to actual needs. This embodiment does not impose any limitations.

[0027] According to the flow cell for nitrate detection of this utility model, an LED chip 31 and a photodiode chip 32 are encapsulated in a lamp bead 3 at one end of the detection channel 22. The photodiode chip 32 detects the luminous intensity of the LED chip 31 during nitrate detection. This allows the initial absorbance detected by the photodiode assembly 4 to be corrected based on the current and initial luminous intensity of the LED chip 31 detected by the photodiode chip 32 when analyzing the liquid absorbance. This avoids the instability of the luminous intensity of the LED chip 31 affecting the detection results of the photodiode assembly 4, ensuring the accuracy of nitrate detection. Moreover, the flow cell has a relatively simple structure and high integration, resulting in a small device size, low production cost, and easy connection with other detection equipment, simplifying the detection process and reducing detection costs.

[0028] In one embodiment of this invention (not shown), the flow cell may further include a data processing unit. The data processing unit is electrically connected to both the photodiode chip 32 and the photodiode assembly 4. The data processing unit corrects the initial absorbance detected by the photodiode assembly 4 based on the current luminous intensity of the LED chip 31 currently detected by the photodiode chip 32 and the initial luminous intensity of the LED chip 31 detected at the start of nitrate detection. In some other embodiments of this invention, the detection results of the photodiode chip 32 and the photodiode assembly 4 can be directly obtained, and then the absorbance of the liquid can be calculated manually. This embodiment does not impose such limitations.

[0029] In one embodiment of this utility model, the flow cell body 1 can be a one-piece structure. When the flow cell body 1 is made of metal material, it can be produced by means of mold casting, etc. Two mounting slots 11 can be formed inside the flow cell body 1. The two mounting slots 11 are respectively used to mount the LED bead 3 and the photodiode assembly 4. A flat transparent glass and a sealing element can be provided at the connection between the mounting slot 11 and the detection flow channel 22 to prevent liquid from entering the mounting slot 11 and affecting the normal operation of the LED bead 3 and the photodiode assembly 4. Figure 1 and 2 As shown, the mounting groove 11 may also be provided with threads and mounting brackets, which facilitates the addition of other structures, such as filters, in the mounting groove 11 in the future, thereby expanding the function of the flow pool.

[0030] In one embodiment of this utility model, the emission wavelength of the LED chip 31 is 220±10nm, corresponding to the wavelength detection range of nitrate. The photodiode chip 32 can be a photodiode chip with a sensitivity wavelength range greater than that of the LED chip 31, so as to ensure the accuracy of luminous intensity detection.

[0031] In one embodiment of this utility model, the LED chip 31 and the photodiode chip 32 are mounted on a ceramic substrate 33. Specifically, the LED chip 31 may adopt a flip-chip structure, and the LED chip 31 and the photodiode chip 32 may be packaged in a 3939 form. The back of the ceramic substrate 33 may be provided with multiple metal contacts 34 for connecting circuits, such as... Figure 4 As shown.

[0032] like Figure 5 As shown, in one embodiment of this utility model, the LED bead 3 may further include a hemispherical focusing lens 35, which is used to focus the light on the LED chip 31. The focusing center of the focusing lens 35 may be located on the same straight line as the center line of the detection channel 22 and the absorbance detection center of the photodiode assembly 4, i.e., the semiconductor center of the photodiode in the photodiode assembly 4, so that the center line of the detection channel 22 is collinear with the light beam emitted from the LED bead 3.

[0033] In a preferred embodiment of this invention, the liquid flow channel 2 can be a Z-shaped flow channel, with the inlet 21 and outlet 23 located at the inlet and outlet of the Z-shaped flow channel, respectively. It is understood that, compared to the commonly used U-shaped flow channel, the Z-shaped flow channel can minimize the distance between the detection flow channel 22 and the inlet 21 and outlet 23 while ensuring the length of the detection flow channel 22. Since the inlet 21 and outlet 23 are not on the same side, the space of the flow cell body 1 can be effectively utilized to a greater extent, which is beneficial for reducing the volume and weight of the flow cell and lowering production costs.

[0034] In one embodiment of this utility model, the liquid inlet 21 is provided with an internal thread, which mates with the Peek connector inserted into the liquid inlet 21 to ensure a seal at the connection between the liquid inlet 21 and the Peek connector, preventing liquid from overflowing from gaps and causing pollution to the testing environment. It is understood that the liquid outlet 23 can also adopt a similar design to the liquid inlet 21 to ensure a seal between the liquid outlet 23 and the Peek connector, etc., which will not be elaborated further here.

[0035] In one specific embodiment of this utility model, the 1 / 4-28UNF threaded hand-tightening peek connector is commonly used in liquid testing. The internal thread can adopt the 1 / 4-28UNF standard to adapt to this type of connector. In some other embodiments of this utility model, other connectors can also be used to connect to the inlet 21 and outlet 23 of the flow cell, such as titanium alloy connectors. In this case, the inlet 21 and outlet 23 can also achieve a seal at the connection by setting a sealing ring or forming a structure that matches the shape of the connector. This embodiment does not impose any limitations on this.

[0036] The following describes the specific process for detecting nitrates in a flow-through cell according to this invention, using a concrete example:

[0037] (1) A pure water mobile phase is introduced into the detection channel 22 through the inlet 21 at a flow rate of 0.3 mL / min, and then discharged from the outlet 23 after passing through the detection channel 22. The LED chip 31 in the lamp bead 3 is driven by current to emit a light beam. The light beam passes through the detection channel 22 and reaches the semiconductor center of the photodiode in the photodiode assembly 4, thereby obtaining the initial absorbance A of the pure water. After correction based on the photodiode chip 32 built into the lamp bead 3, the true absorbance At of the output pure water is obtained. The sample introduction baseline is formed with time t as the abscissa and the corrected true absorbance At as the ordinate. Wherein, At=A+A1-A0, A is the initial absorbance detected by the photodiode assembly 4, A1 is the current luminous intensity of the LED chip 31 detected by the photodiode chip 32 at the current time, and A0 is the initial luminous intensity of the LED chip 31 detected by the photodiode chip 32 at the initial time.

[0038] (2) Take 500 μL of the sample to be tested and add it to the pure water mobile phase. When the sample to be tested passes through the detection channel 22, the absorbance At changes and forms the injection peak.

[0039] (3) Calculate the peak area of ​​the sample to be tested by integrating over time, and obtain the nitrate concentration of the sample to be tested by comparing it with the standard curve of the nitrate standard.

[0040] In the description of this utility model, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. "A plurality of" means two or more, unless otherwise explicitly specified.

[0041] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0042] In this utility model, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0043] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0044] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A flow cell for detecting nitrates, characterized in that, include: Flow cell body (1); A liquid flow channel (2) runs through the main body (1) of the flow cell. The liquid flow channel (2) includes an inlet (21), a straight detection channel (22), and an outlet (23) connected in sequence. The lamp beads (3) and photodiode assembly (4) are located at both ends of the detection channel (22). The lamp beads (3) encapsulate an LED chip (31) and a photodiode chip (32). The photodiode chip (32) is used to detect the luminous intensity of the LED chip (31) during the nitrate detection process. The photodiode assembly (4) is used to detect the initial absorbance of the liquid in the detection channel (22).

2. The flow-through pool according to claim 1, characterized in that, The flow cell body (1) is an integral structure. Two mounting slots (11) are provided inside the flow cell body (1). The two mounting slots (11) are used to install the lamp beads (3) and the photodiode assembly (4), respectively.

3. The flow-through pool according to claim 1, characterized in that, The LED chip (31) emits at a wavelength of 220±10nm.

4. The flow-through cell according to claim 1, characterized in that, The LED chip (31) and the photodiode chip (32) are mounted on a ceramic substrate (33).

5. The flow cell according to claim 1 or 4, characterized in that, The lamp bead also includes a hemispherical focusing lens (35) for focusing light on the LED chip (31).

6. The flow-through cell according to claim 5, characterized in that, The focusing center of the focusing lens (35) is on the same straight line as the center line of the detection channel (22) and the absorbance detection center of the photodiode assembly (4).

7. The flow-through cell according to claim 1, characterized in that, The liquid flow channel (2) is a Z-shaped flow channel, and the liquid inlet (21) and the liquid outlet (23) are located at the inlet and outlet of the Z-shaped flow channel, respectively.

8. The flow cell according to claim 1 or 7, characterized in that, The inlet (21) is provided with an internal thread, which is engaged with the Peek connector inserted into the inlet (21).

9. The flow-through cell according to claim 1, characterized in that, It also includes a data processing unit, which is electrically connected to the photodiode chip (32) and the photodiode assembly (4) respectively. The data processing unit is used to correct the initial absorbance detected by the photodiode assembly (4) based on the current luminous intensity of the LED chip (31) currently detected by the photodiode chip (32) and the initial luminous intensity of the LED chip (31) detected at the start of nitrate detection.

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