Method for reproducing a dnph trap tube

Abstract

The present application relates to a method for reconditioning DNPH trap. The method comprises the following steps: S1, cleaning the recycled DNPH trap; S2, drying the cleaned DNPH trap; S4, adding a certain amount of DNPH solution into the DNPH trap, and the added DNPH solution does not penetrate the DNPH trap but stays in the DNPH trap. In the process of reconditioning the DNPH trap, the DNPH solution does not penetrate the DNPH trap when the DNPH solution is added into the DNPH trap, and the DNPH solution is completely absorbed by the silica gel particles in the DNPH trap; thus, the amount of DNPH substance contained in each reconditioned DNPH trap is determined, so that the reconditioned DNPH traps have good consistency.

Description

Technical Field

[0001] This invention relates to the field of detecting and removing volatile organic compounds in automotive interiors, and more specifically to a method for reconstructing a DNPH trap. Background Technology

[0002] Volatile organic compounds (VOCs) are generated from materials and parts used in automobile manufacturing. These VOCs can harm human health and therefore must be controlled to reduce their levels to meet standards. Currently, DNPH (2,4-dinitrophenyl trap) collection tubes are commonly used for VOC detection and removal. DNPH collection tubes are effective at removing aldehydes and ketones. In most cases, commercially available DNPH collection tubes are purchased directly. However, in some scenarios, the use of commercially available DNPH collection tubes may not be permitted, requiring in-house fabrication. Examples include certain experimental and testing scenarios, and the need to reuse used or discarded DNPH collection tubes.

[0003] The following problems exist in the non-commercial preparation of DNPH traps: the amount of DNPH solution added in different DNPH traps is different, resulting in poor product consistency. Summary of the Invention

[0004] The purpose of this invention is to provide a method for reproducing DNPH traps, in order to solve the problem in the prior art that the amount of DNPH solution in different DNPH traps prepared in non-commercial production is different, and the consistency of DNPH traps is poor.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A method for reconstituted DNPH trapping tubes, comprising:

[0007] Step S1: Clean the recovered DNPH collection tube;

[0008] Step S2: Dry the cleaned DNPH collection tube;

[0009] Step S4: Add a fixed amount of DNPH solution into the DNPH collection tube, ensuring that the added DNPH solution does not penetrate the DNPH collection tube and remains entirely within it.

[0010] According to the above technical solution, during the fabrication of the DNPH trap, the DNPH solution does not penetrate the trap when added; instead, it is completely absorbed by the silica gel particles within the trap. Thus, the amount of DNPH injected into the trap is the weight of the DNPH substance contained within the fabricated DNPH trap, and the amount of DNPH substance in each fabricated DNPH trap is fixed. By controlling the amount of DNPH substance added to each DNPH trap when fabricating different traps, different DNPH traps can have the same or similar DNPH substance content, thereby ensuring good consistency among the fabricated DNPH traps.

[0011] Further, step S1 includes:

[0012] Step S11: Connect n DNPH traps in sequence to form a series trap, with the openings of the first and last ends of adjacent DNPH traps connected together. The series trap has a total opening at the first end and a total opening at the last end. The total opening at the first end is the opening at the first end of the DNPH trap, and the total opening at the last end is the opening at the last end of the DNPH trap that is numbered n.

[0013] Step S12: Connect the first end of the series collection tube to the eluent outlet of the cleaning device.

[0014] Step S13: Eluent is injected from the eluent outlet of the cleaning device into the main opening at the beginning of the series collection tubes to clean the DNPH collection tube which is the first in the sequence at the beginning.

[0015] Step S14: Remove the DNPH trapping tube located at the first end and connect the DNPH trapping tube located at the second end to the eluent outlet of the cleaning device. The DNPH trapping tube located at the second end becomes the new DNPH trapping tube located at the first end in series.

[0016] Step S15, repeat step S13.

[0017] According to the above technical solution, by using the same cleaning device to clean different DNPH collection tubes sequentially through steps S11 to S15, a high cleaning efficiency can be achieved.

[0018] Furthermore, step S1 also includes:

[0019] Step S16: Connect the opening at the beginning of the DNPH collection tube to be cleaned to the opening at the end of the series collection tubes.

[0020] According to the above technical solution, by connecting the DNPH collection tubes to be cleaned in series within the series collection tube, the DNPH collection tubes to be cleaned can be continuously replenished during the cleaning process of the cleaning device, thereby achieving continuous and sustained cleaning of the DNPH collection tubes by the cleaning device, without being limited by the number of DNPH collection tubes included in the series collection tube.

[0021] Further, step S2 includes:

[0022] Step S21: Connect the opening at the beginning or end of the DNPH trap to the outlet of the syringe, and use the syringe to purge the DNPH trap to remove residual eluent.

[0023] Step S22: Purge the DNPH collection tube with a set gas. The flow rate of the set gas used for purging shall not be less than 5 L / min.

[0024] Step S23: Place the DNPH collection tube in a ventilated environment to allow the residual eluent to evaporate.

[0025] According to the above technical solution, by using a large flow rate of set gas to purge the DNPH collection tube in steps S21 to S23 within a unit time, the effect of more thoroughly removing the eluent residue from the DNPH collection tube can be achieved.

[0026] Furthermore, the method for reconstituted DNPH trapping tubes further includes:

[0027] Step S3: Prepare DNPH solution;

[0028] Step S3 includes:

[0029] Step S31: Prepare a saturated DNPH solution;

[0030] Step S32: Mix the saturated DNPH solution with the acidified acetonitrile solvent in a set ratio to obtain an acidic DNPH solution.

[0031] According to the above technical solution, an acidic DNPH solution is first prepared on-site, and the prepared acidic DNPH solution is added to the cleaned and dried DNPH collection tube in the subsequent step S4.

[0032] Further, step S31 includes:

[0033] Step S311: Based on the pure DNPH substance, acetonitrile is selected as the solvent to prepare a supersaturated solution of DNPH;

[0034] Step S312: Heat the supersaturated solution of DNPH, and then cool it after heating to recrystallize DNPH.

[0035] Step S314: Using acetonitrile as a solvent, prepare a supersaturated solution from the recrystallized DNPH and let it stand.

[0036] Step S315: Take the supernatant of the DNPH supersaturated solution to obtain a DNPH saturated solution.

[0037] According to the above technical solution, through the above steps, the DNPH substance is first recrystallized, then the recrystallized DNPH substance is prepared into a supersaturated solution, and finally the supernatant of the supersaturated solution is taken as the DNPH liquid added to the DNPH collection tube in the subsequent step S4, which can make the purity of the DNPH substance finally added to the DNPH collection tube higher.

[0038] Furthermore, step S31 also includes the following steps performed between steps S312 and S314:

[0039] Step S313: Wash the recrystallized DNPH with acetonitrile to improve the purity of DNPH.

[0040] According to the above technical solution, the purity of DNPH can be further improved by washing it with acetonitrile after recrystallization.

[0041] Further, in step S4, a pipette is used to inject DNPH solution into the dried DNPH collection tube, and the injected DNPH solution is distributed on the silica gel particles on the DNPH collection tube.

[0042] According to the above technical solution, a precise amount of DNPH solution can be added into the DNPH collection tube, thereby more accurately controlling the amount of DNPH substance added into the DNPH collection tube.

[0043] Furthermore, the method for reconstituted DNPH trapping tubes further includes:

[0044] Step S5: Dry the DNPH collection tube after injecting the DNPH solution;

[0045] Step S5 includes:

[0046] Step S51: Place the DNPH collection tube in a ventilated environment.

[0047] Step S52: Purge the DNPH collection tube with a set gas. The flow rate of the set gas used for purging shall not be less than 5 L / min.

[0048] According to the above technical solution, by allowing the DNPH collection tube to stand still and ventilate, and by using a large flow rate of set gas to purge the DNPH collection tube within a unit time, the trace amounts of acetonitrile remaining in the DNPH collection tube can be purged more thoroughly, thereby preventing impurities from appearing in the DNPH collection tube.

[0049] Furthermore, the method for reconstituted DNPH trapping tubes further includes:

[0050] Step S6: Block the opening at the beginning and end of the DNPH collection tube.

[0051] According to the above technical solution, the DNPH collection tube is easier to store when the opening at the first end and the opening at the last end are sealed.

[0052] The beneficial effects of this invention are:

[0053] The method for reconstituted DNPH traps provided by this invention ensures that, during the reconstitution process, the DNPH solution does not penetrate the DNPH trap during addition; instead, it is completely absorbed by the silica gel particles within the trap. Thus, the amount of DNPH injected into the trap is the exact weight of the DNPH substance contained within the reconstituted trap, and the amount of DNPH substance in each reconstituted trap is fixed. By controlling the amount of DNPH substance added to each DNPH trap during reconstitution, different DNPH traps can be made to have the same or similar DNPH substance content, resulting in good consistency among the reconstituted DNPH traps. Attached Figure Description

[0054] Figure 1 This is a schematic flowchart of the method for reconstructing the DNPH trapping tube in an embodiment of the present invention;

[0055] Figure 2 for Figure 1 A flowchart illustrating step S1 in the method shown;

[0056] Figure 3 This is a schematic diagram of the DNPH collection tube.

[0057] Figure 4 A schematic diagram of a structure in which multiple DNPH collection tubes are connected in series to form a collection tube;

[0058] Figure 5 for Figure 1 A flowchart illustrating step S2 in the method shown;

[0059] Figure 6 for Figure 1A flowchart illustrating step S3 in the method shown.

[0060] Figure 7 for Figure 6 A flowchart illustrating step S31 in the method shown;

[0061] Figure 8 for Figure 1 The flowchart of step S5 in the method shown is illustrated.

[0062] in:

[0063] 10-Shell; 11-Head opening; 12-Tail opening; 13-Silica gel particles; 14-Sieve plate; 15-Plug; 20-Cleaning device; 21-Eluent. Detailed Implementation

[0064] The embodiments of the present invention will be described below with reference to the accompanying drawings and preferred embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be understood that the preferred embodiments are only for illustrating the present invention and not for limiting the scope of protection of the present invention.

[0065] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Therefore, the drawings only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0066] In one embodiment of the method for reprocessing DNPH traps according to the present invention, the method is used to process used, discarded DNPH traps to restore their functionality, enabling them to be reused and recycled. Figure 1 As shown, the method for reconstructing the DNPH trap specifically includes the following steps S1, S2 and S4.

[0067] Step S1: Clean the recovered DNPH collection tube.

[0068] In step S1, the DNPH trapping tube is cleaned to remove aldehydes, ketones, or other substances collected during previous use. It's important to note that this cleaning in step S1 differs from the normal post-use cleaning process of extracting substances from the DNPH trapping tube. In this embodiment, the cleaning of the DNPH trapping tube is more thorough, whereas the cleaning for extracting substances from the DNPH trapping tube does not aim for complete cleaning.

[0069] In the prior art, acetonitrile solvent is generally used to clean the DNPH trapping tube for extracting substances. In step S1, acetonitrile solvent can also be used to clean the DNPH trapping tube, but the process of cleaning the DNPH trapping tube with acetonitrile solvent differs from cleaning for the purpose of extracting substances from the DNPH trapping tube. These differences include, for example, the number of cleaning cycles, the cleaning time, and the concentration of the acetonitrile solvent used. Based on these differences, the cleaning of the DNPH trapping tube in this embodiment can be more thorough.

[0070] Step S2: Dry the cleaned DNPH collection tube.

[0071] In step S2, the DNPH collection tube is thoroughly dried so that no acetonitrile solvent or DNPH substance remains in the DNPH collection tube, or the residue of the above substances is lower than the set value.

[0072] Thorough drying of the DNPH trap also helps prevent the DNPH solution from penetrating the DNPH trap and flowing out of the DNPH trap when adding the DNPH solution in the subsequent step S4.

[0073] Step S4: Add a fixed amount of DNPH solution into the DNPH collection tube, ensuring that the added DNPH solution does not penetrate the DNPH collection tube and remains entirely within it.

[0074] In step S4, a pipette can be used to inject DNPH solution into the dried DNPH collection tube. The injection of DNPH solution can be carried out slowly. Slow injection of DNPH solution helps the silica gel particles in the DNPH collection tube to fully absorb DNPH solution and prevents DNPH solution from penetrating the DNPH collection tube and flowing out of the DNPH collection tube.

[0075] Of course, in step S4, other methods can also be used to ensure that the DNPH solution added to the DNPH collecting tube does not penetrate and flow to the outside, and is completely absorbed by the silica gel particles in the DNPH collecting tube.

[0076] In this embodiment, during the fabrication of the DNPH trap, the DNPH solution does not penetrate the trap when added; instead, it is completely absorbed by the silica gel particles within the trap. Thus, the amount of DNPH injected into the trap is the weight of the DNPH substance contained within the fabricated DNPH trap, and the amount of DNPH substance in each fabricated DNPH trap is fixed. By controlling the amount of DNPH substance added to each DNPH trap when fabricating different traps, different DNPH traps can have the same or similar DNPH substance content, resulting in good consistency among the fabricated DNPH traps.

[0077] Experimental verification, as shown in Table 1 below, revealed that the DNPH content in the 10 reformulated DNPH traps was similar, exhibiting the same consistency as commercially available DNPH traps. Table 2 below shows that the deviations in formaldehyde and acetaldehyde testing for the 10 reformulated DNPH traps were within 10%, exceeding the industry standard requirement of 20%.

[0078] Table 1. DNPH content in the reconstituted DNPH collection tube

[0079]

[0080] Table 2 shows the deviations between the test results of the reconstituted DNPH trapping tube for formaldehyde and acetaldehyde and the test results of the commercially purchased DNPH trapping tube.

[0081]

[0082] In one embodiment of the method for reconstructing the DNPH trapping tube, such as Figure 2 As shown, step S1 includes the following steps S11 to S15.

[0083] Step S11: Connect n DNPH traps sequentially to form a series trapping tube, with the openings of the first and last ends of adjacent DNPH trapping tubes connected together. The series trapping tube has a total opening at the first end and a total opening at the last end. The total opening at the first end is the opening at the first end of the DNPH trapping tube, and the total opening at the last end is the opening at the last end of the DNPH trapping tube that is the nth end of the DNPH trapping tube.

[0084] like Figure 3As shown, the DNPH collection tube includes a shell 10 with two openings at both ends, referred to as the first opening 11 and the last opening 12. Silica gel particles 13 are disposed inside the shell 10, and sieve plates 14 are disposed on both sides of the silica gel particles 13, separating the silica gel particles 13 from the first opening 11 and the last opening 12. A plug 15 is disposed at each of the first opening 11 and the last opening 12, sealing off the first opening 11 and the last opening 12.

[0085] In step S11, the plugs at the first opening 11 and the last opening 12 are removed, and the first opening 11 and the last opening 12 of the two DNPH collecting tubes are connected to achieve a series connection of the two DNPH collecting tubes. Similarly, three or more DNPH collecting tubes can be connected in series, forming a series collecting tube system. Figure 4 The series trapping tube shown is composed of five DNPH trapping tubes connected in series.

[0086] Step S12, as follows Figure 4 As shown, the main opening at the beginning of the series collection tube is connected to the eluent outlet of the cleaning device.

[0087] In step S12, the cleaning device 20 can be, for example, manifested as Figure 4 The syringe shown contains an eluent 21, for example, acetonitrile solvent.

[0088] Step S13: Eluent 21 is injected from the eluent outlet of the self-cleaning device into the main opening at the beginning of the series collection tubes to clean the DNPH collection tube which is the first in the sequence at the beginning.

[0089] In step S13, with the main opening at the beginning of the series trapping tube connected to the eluent outlet of the cleaning device 20, the cleaning device 20 can inject eluent 21 into the first DNPH trapping tube to clean it, specifically to remove the silica gel particles from the DNPH trapping tube. The silica gel particles can be cleaned until they appear white to the human eye.

[0090] Step S14: Remove the DNPH trapping tube located at the first end and connect the DNPH trapping tube located at the second end to the eluent outlet of the cleaning device. The DNPH trapping tube located at the second end becomes the new DNPH trapping tube located at the first end in series.

[0091] In step S14, once the first DNPH trapping tube is cleaned, it can be removed from the series trapping tubes and await further steps. After the original first DNPH trapping tube is removed, the original second DNPH trapping tube becomes the new first DNPH trapping tube. This new first DNPH trapping tube is connected to the eluent outlet of the cleaning device 20, and is then ready for cleaning.

[0092] Step S15, repeat step S13.

[0093] In step S15, by repeating step S13, the newly sorted DNPH collection tube number 1 can be cleaned. After cleaning, step S14 is started again in sequence. By repeating steps S13 to S14, each DNPH collection tube in the series collection tube can be cleaned continuously.

[0094] In this embodiment, by using the same cleaning device 20 to clean different DNPH collection tubes sequentially through the above steps S11 to S15, a high cleaning efficiency can be achieved.

[0095] In one embodiment of the method for reconstructing the DNPH trapping tube, such as Figure 2 As shown, step S1 may further include:

[0096] Step S16: Connect the opening at the beginning of the DNPH collection tube to be cleaned to the opening at the end of the series collection tubes.

[0097] In this embodiment, by connecting the DNPH collection tubes to be cleaned in series within the series collection tube, the DNPH collection tubes to be cleaned can be continuously replenished during the cleaning process of the cleaning device 20, thereby achieving continuous and sustained cleaning of the DNPH collection tubes by the cleaning device 20, without being limited by the number of DNPH collection tubes included in the series collection tube.

[0098] Specifically, when connecting the DNPH trap to be cleaned to the series trap, the DNPH trap to be cleaned can be connected to the series trap after the DNPH trap numbered 1 is removed each time. The original DNPH trap numbered n is now numbered n-1, and the newly connected DNPH trap becomes the new DNPH trap numbered n.

[0099] In one embodiment of the method for reconstructing the DNPH trapping tube, such as Figure 5 As shown, step S2 includes the following steps S21 to S23.

[0100] Step S21: Connect the opening at the beginning or end of the DNPH trap to the outlet of the syringe, and use the syringe to purge the DNPH trap to remove residual eluent.

[0101] In step S21, the DNPH collection tube is first purged using a syringe to remove any significant eluent residue. The purging standard in this step is that no eluent liquid splashes out.

[0102] The significant removal of eluent residues can reduce the diffusion range of the eluent residues during purging in subsequent step S22.

[0103] Step S22: Purge the DNPH collection tube with a set gas. The flow rate of the set gas used for purging shall not be less than 5 L / min.

[0104] In step S22, the set gas used to purge the DNPH collection tube can be nitrogen.

[0105] In step S22, purging with a large flow rate of set gas per unit time can remove finer eluent residues from the DNPH collection tube and dry the DNPH collection tube more thoroughly.

[0106] Step S23: Place the DNPH collection tube in a ventilated environment to allow the residual eluent to evaporate.

[0107] In step S23, the DNPH collection tube can be left to stand for 4 to 6 hours. Through standing and evaporation, the residue of the eluent can be completely removed.

[0108] In this embodiment, by using steps S21 to S23 to purge the DNPH collection tube with a large flow rate of set gas per unit time, the effect of more thoroughly removing the eluent residue from the DNPH collection tube can be achieved.

[0109] In one embodiment of the method for reconstructing the DNPH trap, the method further includes:

[0110] Step S3: Prepare DNPH solution.

[0111] like Figure 6 As shown, step S3 specifically includes the following steps S31 to S32.

[0112] Step S31: Prepare a saturated DNPH solution.

[0113] Step S32: Mix the saturated DNPH solution with the acidified acetonitrile solvent in a set ratio to obtain an acidic DNPH solution.

[0114] In this embodiment, step S3 can be performed simultaneously with steps S1 and S2, or sequentially. When performed sequentially, steps S1 and S2 can be performed first, followed by step S3, or step S3 can be performed first, followed by steps S1 and S2.

[0115] In this embodiment, an acidic DNPH solution is first prepared on-site, and the prepared acidic DNPH solution is added to the cleaned and dried DNPH collection tube in the subsequent step S4.

[0116] In one embodiment of the method for reconstructing the DNPH trapping tube, such as Figure 7 As shown, step S31 includes the following steps: S311, S312, S314, and S315.

[0117] Step S311: Based on the pure DNPH substance, acetonitrile is selected as the solvent to prepare a supersaturated solution of DNPH.

[0118] Step S312: Heat the supersaturated solution of DNPH, and then cool it to recrystallize the DNPH.

[0119] Step S314: Using acetonitrile as a solvent, prepare a supersaturated solution from the recrystallized DNPH and let it stand.

[0120] Step S315: Take the supernatant of the DNPH supersaturated solution to obtain a DNPH saturated solution.

[0121] In this embodiment, by taking the above steps, the DNPH substance is first recrystallized, and then the recrystallized DNPH substance is prepared into a supersaturated solution. Finally, the supernatant of the supersaturated solution is taken as the DNPH liquid added to the DNPH collection tube in the subsequent step S4, which can make the purity of the DNPH substance finally added to the DNPH collection tube higher.

[0122] In one embodiment of the method for reconstructing the DNPH trapping tube, such as Figure 7 As shown, step S31 may also include actions performed between steps S312 and S314:

[0123] Step S313: Wash the recrystallized DNPH with acetonitrile to improve the purity of DNPH.

[0124] Specifically, in step S313, the recrystallized DNPH can be washed with acetonitrile multiple times. Generally, the more times it is washed, the higher the purity of the DNPH substance is obtained.

[0125] In one embodiment of the method for reconstructing the DNPH trap, in step S4, a pipette is used to inject DNPH solution into the dried DNPH trap, and the injected DNPH solution is distributed on the silica gel particles on the DNPH trap.

[0126] In this embodiment, the above-described configuration allows for the precise addition of a quantitative amount of DNPH solution into the DNPH collection tube, thereby enabling more accurate control over the amount of DNPH substance added to the DNPH collection tube.

[0127] In one embodiment of the method for reconstructing the DNPH trapping tube, such as Figure 1 As shown, the method for reconstructing the DNPH trap may further include:

[0128] Step S5: Dry the DNPH collection tube after injecting the DNPH solution.

[0129] like Figure 8 As shown, step S5 includes the following steps S51 to S52.

[0130] Step S51: Place the DNPH collection tube in a ventilated environment.

[0131] In step S51, the DNPH collection tube can be left to stand for 30 to 60 minutes.

[0132] Step S52: Purge the DNPH collection tube with a set gas. The flow rate of the set gas used for purging shall not be less than 5 L / min.

[0133] In step S52, the set gas used to purge the DNPH collection tube can be nitrogen.

[0134] In this embodiment, by allowing the DNPH collection tube to stand still and ventilating it, and by using a large flow rate of a set gas to purge the DNPH collection tube within a unit time, the trace amounts of acetonitrile remaining in the DNPH collection tube can be blew out more thoroughly, thereby preventing impurities from appearing in the DNPH collection tube.

[0135] In one embodiment of the method for reconstructing the DNPH trapping tube, such as Figure 1 As shown, the method for reconstructing the DNPH trap also includes:

[0136] Step S6: Block the opening at the beginning and end of the DNPH collection tube.

[0137] In this embodiment, the first opening 11 and the last opening 12 of the DNPH collection tube can be sealed with a plug 15. After the first opening 11 and the last opening 12 are sealed, the DNPH collection tube is easier to store.

[0138] To better store the DNPH trap, it can also be placed in a sealed bag and kept in an environment below 4°C.

[0139] The above embodiments are merely preferred embodiments provided to fully illustrate the present invention, and the scope of protection of the present invention is not limited thereto. Equivalent substitutions or modifications made by those skilled in the art based on the present invention are all within the scope of protection of the present invention.

Claims

1. A method for reconstructing a DNPH trapping tube, characterized in that, The method for reconstructing the DNPH trap includes: Step S1: Clean the recovered DNPH collection tube; Step S2: Dry the cleaned DNPH collection tube; Step S4: A fixed amount of DNPH solution is added to the DNPH trapping tube. The added DNPH solution does not penetrate the DNPH trapping tube but remains entirely within it. The DNPH solution is completely absorbed by the silica gel particles inside the DNPH trapping tube. The amount of DNPH substance injected into the DNPH trapping tube is the amount of DNPH substance contained in the reconstituted DNPH trapping tube. The amount of DNPH substance contained in each reconstituted DNPH trapping tube is determined. By controlling the amount of DNPH substance added to each DNPH trapping tube, different DNPH trapping tubes have the same or similar DNPH substance.

2. The method for reconstructing the DNPH collection tube according to claim 1, characterized in that, Step S1 includes: Step S11: Connect n DNPH traps in sequence to form a series trap, with the openings of the first and last ends of adjacent DNPH traps connected together. The series trap has a total opening at the first end and a total opening at the last end. The total opening at the first end is the opening at the first end of the DNPH trap, and the total opening at the last end is the opening at the last end of the DNPH trap that is numbered n. Step S12: Connect the first end of the series collection tube to the eluent outlet of the cleaning device. Step S13: Eluent is injected from the eluent outlet of the cleaning device into the main opening at the beginning of the series collection tubes to clean the DNPH collection tube which is the first in the sequence at the beginning. Step S14: Remove the DNPH trapping tube located at the first end and connect the DNPH trapping tube located at the second end to the eluent outlet of the cleaning device. The DNPH trapping tube located at the second end becomes the new DNPH trapping tube located at the first end in series. Step S15, repeat step S13.

3. The method for reconstructing the DNPH collection tube according to claim 2, characterized in that, Step S1 further includes: Step S16: Connect the opening at the beginning of the DNPH collection tube to be cleaned to the opening at the end of the series collection tubes.

4. The method for reconstructing the DNPH collection tube according to claim 1, characterized in that, Step S2 includes: Step S21: Connect the opening at the beginning or end of the DNPH trap to the outlet of the syringe, and use the syringe to purge the DNPH trap to remove residual eluent. Step S22: Purge the DNPH collection tube with a set gas. The flow rate of the set gas used for purging shall not be less than 5 L / min. Step S23: Place the DNPH collection tube in a ventilated environment to allow the residual eluent to evaporate.

5. The method for reconstructing the DNPH trapping tube according to claim 1, characterized in that, The method for reconstructing the DNPH trap also includes: Step S3: Prepare DNPH solution; Step S3 includes: Step S31: Prepare a saturated DNPH solution; Step S32: Mix the saturated DNPH solution with the acidified acetonitrile solvent in a set ratio to obtain an acidic DNPH solution.

6. The method for reconstructing the DNPH trapping tube according to claim 5, characterized in that, Step S31 includes: Step S311: Based on the pure DNPH substance, acetonitrile is selected as the solvent to prepare a supersaturated solution of DNPH; Step S312: Heat the supersaturated solution of DNPH, and then cool it after heating to recrystallize DNPH. Step S314: Using acetonitrile as a solvent, prepare a supersaturated solution from the recrystallized DNPH and let it stand. Step S315: Take the supernatant of the DNPH supersaturated solution to obtain a DNPH saturated solution.

7. The method for reconstructing the DNPH trapping tube according to claim 6, characterized in that, Step S31 also includes the following steps performed between steps S312 and S314: Step S313: Wash the recrystallized DNPH with acetonitrile to improve the purity of DNPH.

8. The method for reconstructing the DNPH trapping tube according to claim 1, characterized in that, In step S4, a pipette is used to inject DNPH solution into the dried DNPH collection tube, and the injected DNPH solution is distributed on the silica gel particles on the DNPH collection tube.

9. The method for reconstructing the DNPH trapping tube according to claim 1, characterized in that, The method for reconstructing the DNPH trap also includes: Step S5: Dry the DNPH collection tube after injecting the DNPH solution; Step S5 includes: Step S51: Place the DNPH collection tube in a ventilated environment. Step S52: Purge the DNPH collection tube with a set gas. The flow rate of the set gas used for purging shall not be less than 5 L / min.

10. The method for reconstructing the DNPH trapping tube according to claim 1, characterized in that, The method for reconstructing the DNPH trap also includes: Step S6: Block the opening at the beginning and end of the DNPH collection tube.

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