Secondary derivation device for ammonia nitrogen detection

Abstract

The utility model belongs to the technical field of ammonia nitrogen detection, and discloses a secondary derivation device for ammonia nitrogen detection, which comprises a first three-way valve, a second three-way valve, a first heating reaction unit, a second heating reaction unit, a degasser, a detector, a first container and a second container. The ammonia nitrogen sample is firstly mixed with the derivative reagent A pumped out of the first container, is further fully mixed in the first heating reaction unit under a certain temperature condition, is then mixed with the derivative reagent B pumped out of the second container, and is fully reacted in the second heating reaction unit; according to the secondary derivation device, the problem that ammonia nitrogen cannot be detected in an ultraviolet-visible light detector is solved, the ammonia nitrogen can be directly detected at 670-720 nm through the secondary derivation device, the use amount of a sample is small, and the reaction is fast.

Description

Technical Field

[0001] The utility model relates to the technical field of ammonia nitrogen detection, in particular to a secondary derivatization device for ammonia nitrogen detection. Background Art

[0002] Free ammonia (NH3) and ammonium ions (NH 4+ Ammoniacal nitrogen is a nutrient in water that can cause eutrophication. It is a major oxygen-consuming pollutant in water and is toxic to fish and certain aquatic organisms.

[0003] Spectrophotometry is a commonly used method for detecting ammonia nitrogen. A UV-visible detector uses the characteristic absorption of chromatographically separated components within the UV-visible wavelength range to generate an electrical signal. Before ammonia nitrogen can be detected using a UV-visible detector, it must undergo a derivatization reaction. Currently, derivatization devices used for ammonia nitrogen detection only have a single heated reaction chamber, housing the derivatization reagent and the sample being tested. This results in low derivatization reaction efficiency and significant fluctuations, making it difficult to reliably detect ammonia nitrogen. Utility Model Content

[0004] In view of the shortcomings of the prior art described above, the purpose of the present invention is to provide a secondary derivatization device for ammonia nitrogen detection, which changes the commonly used one heating reaction chamber into two heating reaction chambers, and pumps the derivatization reagent in batches, so that ammonia nitrogen can be directly detected at 670-720nm, with less sample consumption and faster reaction.

[0005] The technical solution of the utility model is:

[0006] A secondary derivatization device for ammonia nitrogen detection comprises a first three-way valve, a second three-way valve, a first heating reaction unit, a second heating reaction unit, a degasser, a first container and a second container; the first three-way valve has three connecting ends, namely a first end, a second end and a third end; wherein the first end is connected to a liquid inlet pipe, the second end is connected to the first container through a first pipe, a first peristaltic pump is provided on the first pipe, and the third end is connected to the liquid inlet end of the first heating reaction unit through a second pipe; the second three-way valve has three connecting ends, namely a fourth end, a fifth end and a sixth end; wherein the liquid outlet end of the first heating reaction unit is connected to the fourth end through a third pipe, the fifth end is connected to the second container through a fourth pipe, a second peristaltic pump is provided on the fourth pipe, and the sixth end is connected to the liquid inlet end of the second heating reaction unit through the fifth pipe; the liquid outlet end of the second heating reaction unit is connected to the liquid inlet end of the degasser through a sixth pipe.

[0007] Optionally, in the secondary derivatization device for ammonia nitrogen detection as described above, the first heating reaction unit and the second heating reaction unit have the same structure; wherein, the first heating reaction unit includes a heating pipe and a heating layer, the two ends of the heating pipe are respectively connected to the second pipe and the third pipe, and the heating layer is arranged on the outer wall of the heating pipe.

[0008] Optionally, in the secondary derivatization device for ammonia nitrogen detection as described above, the first heating reaction unit and the second heating reaction unit have the same structure; wherein, the second heating reaction unit includes a reaction chamber and a heating component, and the heating component is arranged inside the reaction chamber.

[0009] Optionally, in the secondary derivatization device for ammonia nitrogen detection as described above, a first one-way valve, a first damper and a first pressure gauge are provided on the first pipeline.

[0010] Optionally, in the secondary derivatization device for ammonia nitrogen detection as described above, two first one-way valves are provided, and the first damper is provided between the two first one-way valves.

[0011] Optionally, in the secondary derivatization device for ammonia nitrogen detection as described above, a second one-way valve, a second damper and a second pressure gauge are provided on the fourth pipeline.

[0012] Optionally, in the secondary derivatization device for ammonia nitrogen detection as described above, two second one-way valves are provided, and the second damper is provided between the two second one-way valves.

[0013] Optionally, the secondary derivatization device for ammonia nitrogen detection as described above, wherein a first pressure gauge is provided on the first pipeline, a second pressure gauge is provided on the fourth pipeline, and further comprises a controller, wherein the signal output ends of the first pressure gauge and the second pressure gauge are connected to the controller, and the signal output end of the controller is connected to the signal input end of the first peristaltic pump and the second peristaltic pump to control the flow rate ratio of the first pipeline and the fourth pipeline between 1.5:1 and 1:1.5.

[0014] Optionally, in the secondary derivatization device for ammonia nitrogen detection as described above, the flow rates of the first peristaltic pump and the second peristaltic pump are both set to 0.05-0.20 mL / min.

[0015] Optionally, the secondary derivatization device for ammonia nitrogen detection as described above further includes a detector and a waste liquid collection container, the liquid outlet end of the degasser is connected to the liquid inlet end of the detector through a seventh pipe, and the liquid outlet end of the detector is connected to the waste liquid collection container through an eighth pipe.

[0016] Compared with the prior art, the beneficial effects of the present invention are:

[0017] The utility model provides two heating reaction units, so that an incoming ammonia nitrogen sample is first mixed with a derivatization reagent A pumped out of a first container, and further fully mixed in the first heating reaction unit under certain temperature conditions, and then mixed with a derivatization reagent B pumped out of a second container, and fully reacted in the second heating reaction unit, thereby solving the problem that ammonia nitrogen cannot be detected in an ultraviolet-visible light detector. Through the secondary derivatization device, ammonia nitrogen can be directly detected at 670-720 nm, with a small amount of sample used and a fast reaction. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0019] Figure 1 This is a structural diagram of a secondary derivatization device for ammonia nitrogen detection according to an embodiment of the utility model.

[0020] Figure 2 This is a structural schematic diagram of the first heating reaction unit in a secondary derivatization device for ammonia nitrogen detection according to an embodiment of the present invention.

[0021] Figure 3 This is a structural schematic diagram of a secondary derivatization device for ammonia nitrogen detection according to an embodiment of the present invention when provided with a controller.

[0022] Figure 4 This is a structural schematic diagram of a secondary derivatization device for ammonia nitrogen detection according to an embodiment of the present invention after adding a detector and a waste liquid collection container.

[0023] In the figure, 1 is the first three-way valve, 101 is the first end, 102 is the second end, 103 is the fourth end, 2 is the second three-way valve, 201 is the fourth end, 202 is the fifth end, 203 is the sixth end, 3 is the first heating reaction unit, 301 is the heating pipe, 302 is the heating layer, 4 is the second heating reaction unit, 401 is the heating chamber, 402 is the heating component, 5 is the degasser, 6 is the first container, 7 is the second container, 8 is the liquid inlet pipe, 9 is The first pipeline, 10 is the first peristaltic pump, 11 is the second pipeline, 12 is the third pipeline, 13 is the fourth pipeline, 14 is the second peristaltic pump, 15 is the fifth pipeline, 16 is the sixth pipeline, 17 is the first one-way valve, 18 is the first damper, 19 is the first pressure gauge, 20 is the second one-way valve, 21 is the second damper, 22 is the second pressure gauge, 23 is the controller, 24 is the detector, 25 is the waste liquid collection container, 26 is the seventh pipeline, and 27 is the eighth pipeline. DETAILED DESCRIPTION

[0024] The following describes the embodiments of the present invention through specific examples. Those skilled in the art will readily understand the other advantages and benefits of the present invention from the disclosure herein. The present invention may also be implemented or applied through various other specific embodiments, and the details in this specification may be modified or altered based on different perspectives and applications without departing from the spirit of the present invention. It should be noted that the following embodiments and features within these embodiments may be combined with one another, unless they conflict.

[0025] In the description of this utility model, unless otherwise specified, "plurality" means two or more; the terms "upper," "lower," "left," "right," "inner," "outer," "front end," "rear end," "head," "tail," etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings and are intended solely to facilitate the description of this utility model and simplify the description. They do not indicate or imply that the devices or components referred to must have a specific direction, be constructed, or operate in a specific direction, and therefore should not be construed as limiting this utility model. Furthermore, the terms "first," "second," "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0026] In the description of this utility model, it should be noted that, unless otherwise specified or limited, the terms "connected" and "connection" should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integral connection; mechanical connection, electrical connection; direct connection, or indirect connection through an intermediary. Those skilled in the art will understand the specific meanings of the above terms in this utility model based on specific circumstances.

[0027] The present invention will now be further described with reference to the accompanying drawings.

[0028] Existing derivatization devices for ammonia nitrogen detection only have a single heated reaction chamber. During the derivatization reaction, two derivatization reagents must be added simultaneously to the chamber, resulting in low efficiency and large fluctuations in the reaction, making it impossible to detect ammonia nitrogen.

[0029] Based on this, an embodiment of the present invention provides a secondary derivatization device for ammonia nitrogen detection, which changes from the commonly used one heating reaction chamber to two heating reaction chambers, and pumps in derivatization reagents in batches, so that ammonia nitrogen can be directly detected at 670-720nm, with less sample consumption and faster reaction.

[0030] like Figure 1 As shown, the secondary derivatization device for ammonia nitrogen detection includes a first three-way valve 1, a second three-way valve 2, a first heating reaction unit 3, a second heating reaction unit 4, a degasser 5, a first container 6 and a second container 7; the first three-way valve 1 has three connecting ends, namely a first end 101, a second end 102 and a third end 103; wherein the first end 101 is connected to the liquid inlet pipe 8, the second end 102 is connected to the first container 6 through a first pipe 9, a first peristaltic pump 10 is provided on the first pipe 9, and the third end 103 is connected to the first heating pipe 8 through a second pipe 11. The liquid inlet end of the reaction unit 3; the second three-way valve 2 has three connecting ends, namely the fourth end 201, the fifth end 202 and the sixth end 203; wherein, the liquid outlet end of the first heating reaction unit 3 is connected to the fourth end 201 through the third pipe 12, the fifth end 202 is connected to the second container 7 through the fourth pipe 13, the second peristaltic pump 14 is provided on the fourth pipe 13, and the sixth end 203 is connected to the liquid inlet end of the second heating reaction unit 4 through the fifth pipe 15; the liquid outlet end of the second heating reaction unit 4 is connected to the liquid inlet end of the degasser 5 through the sixth pipe 16.

[0031] In this embodiment, the first container 6 contains a derivatization reagent A, and the second container 7 contains a derivatization reagent B. The derivatization reagent A is composed of salicylic acid, sodium hydroxide, potassium sodium tartrate, sodium nitrosopentacyanoferrate (Ш), and an aqueous medium, while the derivatization reagent B is composed of sodium hypochlorite, sodium hydroxide, and an aqueous medium.

[0032] In this example, derivatization reagents A and B are added in batches. The sample is thoroughly mixed with derivatization reagent A before being mixed with derivatization reagent B to initiate the derivatization reaction. The basic principle of the derivatization reaction is that in an alkaline medium (pH = 11.6), in the presence of sodium nitrosopentacyanoferrate (Ш), ammonia and ammonium ions in water react with salicylic acid and hypochlorite ions to form a blue compound with maximum absorption at a specific wavelength, the photometry of which is measured using a spectrophotometer. This type of reaction is known as the Berthelot reaction. The mechanism of this type of reaction is relatively complex, proceeding in steps: the first step is the reaction of ammonia with hypochlorite to form chloramine. The second step is the reaction of chloramine with salicylic acid to form an intermediate, 5-aminosalicylic acid. The third step is the conversion of 5-aminosalicylic acid to quinoneimine. Finally, the quinoneimine and salicylic acid condense to form indophenol blue.

[0033] During specific implementation, the mobile phase is pumped into the first three-way valve 1 through the liquid inlet pipe 8, wherein the mobile phase is the sample to be tested, usually a solution containing ammonia nitrogen. At the same time, the first peristaltic pump 10 is started, and the derivatization reagent A in the first container 6 is pumped to the first three-way valve 1 through the first pipe 9. The mobile phase and the derivatization reagent A are first mixed in the second pipe 11 through the third end 103 of the first three-way valve 1. The resulting mixed liquid will further enter the first heating reaction unit 3 for sufficient mixing. The first heating reaction unit 3 provides temperature conditions for the mixing of the derivatization reagent A and the mobile phase. The temperature condition can be set to 30 to 60°C. The fully mixed mixed liquid enters the second three-way valve 2 through the third pipe 12. According to the flow rate of the mixed liquid, the second peristaltic pump 14 is started at an appropriate time so that when the fully mixed mixed liquid just enters the second three-way valve 2, the derivatization reagent B in the second container 7 enters the second peristaltic pump 14 through the fourth pipe 13 to be premixed with the fully mixed mixed liquid, and enters the second reaction heating unit 4 through the fifth pipe 15. The second reaction heating unit 4 provides the temperature conditions required for the derivatization reaction. At this time, when the mobile phase has been fully mixed with the derivatization reagent A, it is mixed with the derivatization reagent B. The derivatization reaction can proceed quickly. The resulting solution containing the reactants enters the degasser 5 from the sixth pipe 16 to remove bubbles that may exist in the solution to facilitate subsequent detection by the detector. The derivatization reaction solution finally obtained can directly detect the ammonia nitrogen content through the detector.

[0034] In some embodiments, the first heating reaction unit 3 and the second heating reaction unit 4 have the same structure. Figure 2 As shown, the first heating reaction unit 3 includes a heating pipe 301 and a heating layer 302 . The two ends of the heating pipe 301 are respectively connected to the second pipe 11 and the third pipe 12 . The heating layer 302 is arranged on the outer wall of the heating pipe 301 .

[0035] In this embodiment, the heating layer 302 can be an electric heating component, such as a resistance wire, which can be wound around the outer wall of the heating pipe 301. When energized, the heating layer 302 generates heat energy, thereby increasing the temperature of the heating pipe 301. This allows the mixture of the mobile phase and the derivatization reagent A to be fully mixed within a certain temperature range as it passes through the heating pipe 301. To ensure effective temperature control, a temperature sensor can be configured and disposed within the heating pipe 301. A temperature controller is provided to receive the temperature signal collected by the temperature sensor and control the opening and closing of the heating layer 302 based on the temperature signal and a set temperature threshold. If the temperature signal indicates that the set temperature threshold has been reached, the heating of the heating layer 302 is stopped; otherwise, the heating layer 302 is activated.

[0036] In this embodiment, the heating layer 302 can also be implemented as a water bath interlayer. During the operation of the secondary derivatization device, constant temperature water is introduced into the water bath interlayer to control the heating pipe 301 to be at a set temperature.

[0037] In some embodiments, the first heating reaction unit 3 and the second heating reaction unit 4 have the same structure. Taking the second heating reaction unit 4 as an example, Figure 1 As shown, the second heating reaction unit 4 includes a reaction chamber 401 and a heating component 402, and the heating component 402 is arranged inside the reaction chamber 401. Wherein, the heating component 402 is used to provide temperature conditions. For example, the heating component 402 may include an electric heating component, a temperature sensor and a temperature controller, and the temperature controller is connected to the electric heating component and the temperature sensor. The temperature sensor and the electric heating component are both arranged inside the reaction chamber 401. The temperature sensor collects the temperature signal inside the reaction chamber 401 and feeds it to the temperature controller. The temperature controller is based on a set temperature threshold. If the temperature signal does not reach the set temperature threshold, the electric heating component is started, otherwise the electric heating component is turned off to maintain a constant temperature in the reaction chamber 401, so that when the solution (such as a solution comprising a mobile phase, a derivatization reagent A and a derivatization reagent B) enters the reaction chamber 401, the derivatization reaction is carried out quickly, thereby improving the efficiency of ammonia nitrogen detection.

[0038] In some embodiments, a first one-way valve 17 , a first damper 18 and a first pressure gauge 19 are provided on the first pipeline 9 .

[0039] In this embodiment, the first one-way valve 17 is used to ensure that the derivatization reagent A in the first container 6 flows toward the first three-way valve 1 to prevent the mobile phase from entering the first container 6. The first damper 18 is used in conjunction with a first pressure gauge 19 to effectively prevent the impact of water hammer and improve the service life of the first pressure gauge 19.

[0040] In some embodiments, two first one-way valves 17 are provided, and the first damper 18 is provided between the two first one-way valves 17 .

[0041] In this embodiment, two first one-way valves 17 are provided to further prevent the mobile phase from entering the first container 6 and the derivatization reagent A from flowing back.

[0042] In some embodiments, a second one-way valve 20 , a second damper 21 and a second pressure gauge 22 are provided on the fourth pipeline 13 .

[0043] In this embodiment, the second one-way valve 20 ensures that the derivatization reagent B in the second container 7 flows toward the second three-way valve 2, thereby preventing the complete mixture of the mobile phase and the derivatization reagent A from entering the second container 7 and preventing backflow of the derivatization reagent B. The second damper 21 is used in conjunction with the second pressure gauge 22 to effectively prevent water hammer and extend the service life of the second pressure gauge 22.

[0044] In some embodiments, two second one-way valves 20 are provided, and the second damper 21 is provided between the two second one-way valves 20 .

[0045] In this embodiment, two second one-way valves 20 are provided to further prevent the fully mixed liquid of the mobile phase and the derivatization reagent A from entering the second container 7 and to prevent the derivatization reagent B from flowing back.

[0046] In some embodiments, as Figure 3 As shown, a first pressure gauge 19 is provided on the first pipeline 9, and a second pressure gauge 22 is provided on the fourth pipeline 13. The secondary derivatization device for ammonia nitrogen detection also includes a controller 23. The signal output ends of the first pressure gauge 19 and the second pressure gauge 22 are connected to the controller 23. The signal output end of the controller 23 is connected to the signal input end of the first peristaltic pump 10 and the second peristaltic pump 14 to control the flow rate ratio of the first pipeline 9 and the fourth pipeline 13 to be between 1.5:1 and 1:1.5.

[0047] Taking into account the derivatization reaction, the input amount of derivatization reagent A and derivatization reagent B should be controlled, and the usage ratio of derivatization reagent A and derivatization reagent B is usually between 1.5:1 and 1:1.5. Therefore, when the size parameters of the first pipeline 9 and the fourth pipeline 13 are consistent, that is, the cross-sectional areas of the first pipeline 9 and the fourth pipeline 13 are equal, the pressure values of the first pressure gauge 19 and the second pressure gauge 22 can reflect the flow rates of the first pipeline 9 and the fourth pipeline 13, and controlling different flow rates can achieve the control of the usage ratio of the derivatization reagent A and the derivatization reagent B. In this embodiment, by setting a controller 23, based on the pressure values of the first pipeline 9 and the fourth pipeline 13 fed by the first pressure gauge 19 and the second pressure gauge 22, according to the set ratio, the operating parameters of the first peristaltic pump 10 and the second peristaltic pump 14 are adjusted, and the flow rate ratio of the first pipeline 9 and the fourth pipeline 13 can be controlled to be between 1.5:1 and 1:1.5, so that the derivatization reaction can be carried out effectively.

[0048] In some embodiments, the flow rates of the first peristaltic pump 9 and the second peristaltic pump 13 are both set to 0.05-0.20 mL / min. That is, the controller 23 controls the flow rates of the first peristaltic pump 9 and the second peristaltic pump 13 within the range of 0.05-0.20 mL / min.

[0049] In some embodiments, as Figure 4 As shown, the secondary derivatization device for ammonia nitrogen detection also includes a detector 24 and a waste liquid collection container 25. The liquid outlet end of the degasser 5 is connected to the liquid inlet end of the detector 24 through a seventh pipe 26, and the liquid outlet end of the detector 24 is connected to the waste liquid collection container 25 through an eighth pipe 27.

[0050] In this embodiment, detector 24 can be a UV-visible light detector. Specifically, the reactant solution obtained from the final derivatization reaction, after being degassed by degasser 5, passes through seventh conduit 26 and enters the UV-visible light detector for ammonia nitrogen detection. The specific principles of ammonia nitrogen detection are well-known and will not be elaborated on here. The waste liquid after final detection flows through eighth conduit 27 into waste liquid collection container 25 for collection. The collected waste liquid is generally subjected to uniform purification treatment before discharge.

[0051] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention, and they should all be included in the scope of the claims and description of the present invention.

Claims

1. A secondary derivatization device for ammonia nitrogen detection, characterized in that: It includes a first three-way valve, a second three-way valve, a first heating reaction unit, a second heating reaction unit, a degasser, a first container and a second container; The first three-way valve has three connecting ends, namely a first end, a second end, and a third end; wherein the first end is connected to the liquid inlet pipe, the second end is connected to the first container via a first pipe, a first peristaltic pump is provided on the first pipe, and the third end is connected to the liquid inlet end of the first heating reaction unit via a second pipe; The second three-way valve has three connecting ends, namely a fourth end, a fifth end, and a sixth end; wherein the liquid outlet end of the first heating reaction unit is connected to the fourth end via a third pipe, the fifth end is connected to the second container via a fourth pipe, a second peristaltic pump is provided on the fourth pipe, and the sixth end is connected to the liquid inlet end of the second heating reaction unit via a fifth pipe; The liquid outlet of the second heating reaction unit is connected to the liquid inlet of the degasser through a sixth pipeline.

2. The secondary derivatization device for ammonia nitrogen detection according to claim 1, characterized in that: The first heating reaction unit and the second heating reaction unit have the same structure; wherein, the first heating reaction unit includes a heating pipe and a heating layer, the two ends of the heating pipe are respectively connected to the second pipe and the third pipe, and the heating layer is arranged on the outer wall of the heating pipe.

3. The secondary derivatization device for ammonia nitrogen detection according to claim 1, characterized in that: The first heating reaction unit and the second heating reaction unit have the same structure; wherein, the second heating reaction unit includes a reaction chamber and a heating component, and the heating component is arranged inside the reaction chamber.

4. The secondary derivatization device for ammonia nitrogen detection according to claim 1, characterized in that: The first pipeline is provided with a first one-way valve, a first damper and a first pressure gauge.

5. The secondary derivatization device for ammonia nitrogen detection according to claim 4, characterized in that: There are two first one-way valves, and the first damper is arranged between the two first one-way valves.

6. The secondary derivatization device for ammonia nitrogen detection according to claim 1, characterized in that: The fourth pipeline is provided with a second one-way valve, a second damper and a second pressure gauge.

7. The secondary derivatization device for ammonia nitrogen detection according to claim 6, characterized in that: Two second one-way valves are provided, and the second damper is provided between the two second one-way valves.

8. The secondary derivatization device for ammonia nitrogen detection according to claim 1, characterized in that: A first pressure gauge is provided on the first pipeline, a second pressure gauge is provided on the fourth pipeline, and a controller is also included. The signal output ends of the first pressure gauge and the second pressure gauge are connected to the controller, and the signal output end of the controller is connected to the signal input ends of the first peristaltic pump and the second peristaltic pump to control the flow rate ratio of the first pipeline and the fourth pipeline between 1.5:1 and 1:1.

5.

9. The secondary derivatization device for ammonia nitrogen detection according to claim 1, characterized in that: The flow rates of the first peristaltic pump and the second peristaltic pump are both set to 0.05-0.20 mL / min.

10. The secondary derivatization device for ammonia nitrogen detection according to claim 1, characterized in that: It also includes a detector and a waste liquid collection container. The liquid outlet of the degasser is connected to the liquid inlet of the detector through a seventh pipe, and the liquid outlet of the detector is connected to the waste liquid collection container through an eighth pipe.

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