Automatic compensation total phosphorus determination method and device based on ammonium molybdate spectrophotometry

Abstract

The invention provides a total phosphorus determination method and device capable of realizing automatic compensation based on ammonium molybdate spectrophotometry. The method comprises the following steps: adding potassium persulfate into a sample for digestion to obtain a first liquid; adding ascorbic acid into the first liquid to obtain second liquid; adding sulfuric acid into the second liquid to obtain third liquid; performing colorimetric measurement on the third liquid to obtain first absorbance; adding molybdate into the third liquid to obtain fourth liquid; performing colorimetric measurement on the fourth liquid to obtain second absorbance; and obtaining the phosphorus content of the sample according to the first absorbance and the second absorbance. According to the invention, ascorbic acid and sulfuric acid are added for color comparison in advance, so that the absorbance of a blank test can be obtained, and the absorbance of a sample can be obtained by further adding molybdate. The phosphorus content of the sample can be obtained by deducting the two absorbance values. According to the method, manual operation is not needed, the sample usage amount is reduced, and the test number is reduced.

Description

Technical Field

[0001] This application relates to the field of environmental monitoring technology, specifically to a method and apparatus for determining total phosphorus based on ammonium molybdate spectrophotometry with automatic compensation. Background Technology

[0002] In existing technologies, the determination of total phosphorus in water samples containing turbidity or color requires the preparation of a separate blank sample. After digestion, a turbidity and color compensation solution is added, and then the absorbance of the blank sample is subtracted from the absorbance of the sample. This method has two drawbacks for determining samples containing turbidity or color: first, it requires manual judgment to determine whether turbidity and color compensation is needed, increasing labor and time costs; second, samples requiring turbidity or color compensation need to use two colorimetric tubes simultaneously for comparison and subtraction, increasing the sample volume. Summary of the Invention

[0003] This application provides a method and apparatus for determining total phosphorus based on ammonium molybdate spectrophotometry with automatic compensation, which can solve the technical problems of existing technologies that require manual judgment of turbidity and color and consume a large amount of sample.

[0004] In a first aspect, embodiments of this application provide an automatically compensated method for determining total phosphorus based on ammonium molybdate spectrophotometry, comprising: The sample was digested with potassium persulfate to obtain the first liquid; Add ascorbic acid to the first liquid to obtain the second liquid; Adding sulfuric acid to the second liquid yields a third liquid; The first absorbance is obtained by colorimetric measurement of the third liquid; Adding molybdate to the third liquid yields a fourth liquid; The fourth liquid was subjected to colorimetric measurement to obtain a second absorbance; The phosphorus content of the sample is obtained based on the first absorbance and the second absorbance.

[0005] Further, in one embodiment, obtaining the phosphorus content of the sample based on the first absorbance and the second absorbance includes: The third absorbance is obtained by subtracting the first absorbance from the second absorbance, and the phosphorus content is obtained by using the third absorbance according to the working curve.

[0006] Furthermore, in one embodiment, the volume of the third liquid used for colorimetric measurement is smaller than the volume of the fourth liquid used for colorimetric measurement.

[0007] Furthermore, in one embodiment, the ratio of the volume of the third liquid used for colorimetric measurement to the volume of the fourth liquid used for colorimetric measurement is 5:8.

[0008] Furthermore, in one embodiment, the sulfuric acid added to the second liquid is a 1:1 sulfuric acid solution.

[0009] Furthermore, in one embodiment, in the addition of the third liquid to the molybdate, the added molybdate is a solution of ammonium molybdate and potassium antimony tartrate dissolved in water.

[0010] Furthermore, in one embodiment, the first liquid is diluted with water to a fixed volume before adding ascorbic acid to the first liquid.

[0011] Furthermore, in one embodiment, at least 30 seconds are elapsed after the addition of ascorbic acid to the first liquid before the addition of sulfuric acid to the second liquid is performed.

[0012] Secondly, embodiments of this application also provide an automatically compensated total phosphorus determination device based on ammonium molybdate spectrophotometry, characterized in that it includes: The digestion module is used to digest the sample by adding potassium persulfate to obtain the first liquid; An ascorbic acid addition module is used to add ascorbic acid to the first liquid to obtain a second liquid; A sulfuric acid addition module is used to add sulfuric acid to the second liquid to obtain a third liquid; The first colorimetric module is used to perform colorimetric measurements on the third liquid to obtain a first absorbance; A molybdate addition module is used to add molybdate to the third liquid to obtain a fourth liquid; The second colorimetric module is used to perform colorimetric measurements on the fourth liquid to obtain a second absorbance; The result acquisition module is used to obtain the phosphorus content of the sample based on the first absorbance and the second absorbance.

[0013] Furthermore, in one embodiment, the first colorimetric module and the second colorimetric module are the same module, and / or, at least two of the ascorbic acid addition module, sulfuric acid addition module, and molybdate addition module are the same module.

[0014] This application provides an automatically compensated method and apparatus for the determination of total phosphorus based on ammonium molybdate spectrophotometry. By adding ascorbic acid and sulfuric acid for pre-colorimetric analysis, the absorbance of a blank test can be obtained. Further addition of molybdate yields the absorbance of the sample. The phosphorus content of the sample is obtained by subtracting the two absorbance values. This method eliminates the need for manual operation, reduces sample usage, and decreases the number of tests required, making it more suitable for fully automated total phosphorus analyzers and unmanned laboratories. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the current process for determining total phosphorus based on ammonium molybdate spectrophotometry. Figure 2 This is a schematic flowchart of a method for determining total phosphorus based on ammonium molybdate spectrophotometry with automatic compensation, as described in one embodiment of this application. Figure 3 This is a schematic flowchart of a method for determining total phosphorus based on ammonium molybdate spectrophotometry with automatic compensation, as described in another embodiment of this application. Figure 4 This is a schematic diagram of the structure of a total phosphorus determination device with automatic compensation based on ammonium molybdate spectrophotometry in one embodiment of this application; Detailed Implementation

[0016] To enable those skilled in the art to better understand the present application, 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 only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present application.

[0017] Total phosphorus refers not to a specific phosphorus compound, but rather to the total amount of phosphorus in all forms in a water sample. It is a key indicator in environmental monitoring, water treatment, and eutrophication research. Phosphorus is an essential nutrient for organisms, but excessive phosphorus entering water bodies can cause serious environmental problems. Total phosphorus includes dissolved, particulate, organic, and inorganic phosphorus.

[0018] Spectrophotometry is an analytical technique widely used in chemical, biological, and environmental testing. Its core principle is Beer-Lambert's law, which states that when a beam of monochromatic light of a specific wavelength passes through a solution of a analyte, its absorbance is directly proportional to the solution's concentration and optical path length. By measuring the sample's absorption of light and comparing it to a standard series of known concentrations, the content of the analyte can be accurately calculated. Spectrophotometry is a more precise colorimetric method. The colorimetric testing mentioned in this application can refer to testing performed using a spectrophotometer.

[0019] Sulfuric acid (1:1): This refers to a sulfuric acid solution obtained by mixing 1 volume of concentrated sulfuric acid with 1 volume of water.

[0020] In existing technologies, the determination of total phosphorus in water samples containing turbidity or color requires the preparation of a blank sample, digestion, addition of turbidity and color compensation solution, and then subtraction of the blank sample's absorbance from the sample's absorbance. This method has two drawbacks for samples containing turbidity or color: first, it requires manual judgment to determine whether turbidity and color compensation is needed, increasing labor and time costs; second, samples requiring turbidity or color compensation need to use two colorimetric tubes simultaneously for comparison and subtraction, increasing the sample volume.

[0021] The existing method for determining total phosphorus in water is the national standard GB 11893-89, "Determination of Total Phosphorus in Water - Ammonium Molybdate Spectrophotometric Method." This standard specifies a method for determining total phosphorus using potassium persulfate (or nitric acid-perchloric acid) as an oxidant, digesting unfiltered water samples, and then using the ammonium molybdate spectrophotometric method. (Reference) Figure 1 As shown, the detailed steps of this standard are as follows: As shown in step ①, take 25 ml of the sample as the test sample, add 4 mL of potassium persulfate to the test sample, seal the graduated tube with a stopper, and tie the glass stopper tightly with a small piece of cloth and thread. Place the tube in a large beaker and heat it in a high-pressure steam sterilizer. When the pressure reaches 1.1 kg / cm² and the corresponding temperature is 120℃, maintain this temperature for 30 minutes and then stop heating. After the pressure gauge reading drops to zero, remove the tube and let it cool. Then dilute with water to the mark. Add 1 mL of ascorbic acid solution to each digestion solution and mix well. After 30 seconds, add 2 mL of molybdate solution and mix thoroughly. After standing at room temperature for 15 minutes, use a 30 mm path length cuvette to measure the absorbance at a wavelength of 700 nm, using water as a reference. After subtracting the absorbance of the blank test, find the phosphorus content from the working curve.

[0022] If the sample contains turbidity or color, a blank sample needs to be prepared according to step ② (the preceding steps are the same as in step ①, and the sample is diluted with water to the mark after digestion). Then, 3 mL of turbidity-color compensation solution is added to the sample, but ascorbic acid solution and molybdate solution are not added. Then, the absorbance of the blank sample is subtracted from the absorbance of the sample sample (the absorbance measured in step ① minus the absorbance measured in step ② yields the result for the sample).

[0023] In this standard, the preparation of the molybdate solution is as follows: Dissolve 13g of ammonium molybdate in 100mL of water. Dissolve 0.35g of potassium antimony tartrate in 100mL of water. While stirring continuously, slowly add the ammonium molybdate solution to 300mL of sulfuric acid (1:1), then add the potassium antimony tartrate solution and mix thoroughly. The preparation of the turbidity-color compensation solution is as follows: Mix two volumes of sulfuric acid (1:1) and one volume of ascorbic acid solution.

[0024] In this standard, the reaction principle is as follows: Digestion process: Under neutral conditions, potassium persulfate or nitric acid-perchloric acid is used to digest the water sample, oxidizing all forms of phosphorus (such as organic and inorganic phosphorus) to orthophosphate (PO4). 3- ). Color reaction: In an acidic medium, orthophosphate reacts with ammonium molybdate to form phosphomolybdic heteropolyacid. The reaction equation is as follows: 3PO4 3- + 12MoO4 2- + 27H + → H3[P(Mo3O 10 )4] + 12H2O Subsequently, in the presence of potassium antimony tartrate (antimony salt), phosphomolybdic heteropolyacid was reduced by ascorbic acid to the blue phosphomolybdic blue complex. Measurement method: The absorbance of the blue complex was measured at 700 nm using a spectrophotometer, and the total phosphorus concentration was calculated based on the standard curve. As mentioned above, the existing standard for determining total phosphorus in water requires manual judgment to determine whether turbidity and color compensation should be performed on the sample, and two colorimetric tubes are needed for comparison experiments on the same sample, which cannot meet the requirements of unmanned laboratories.

[0025] The purpose of this application is to overcome the shortcomings of existing technologies by providing an automatically compensated method and apparatus for the determination of total phosphorus based on ammonium molybdate spectrophotometry. This method involves pre-conducting colorimetric analysis with ascorbic acid and sulfuric acid to obtain the absorbance of a blank test. Further addition of molybdate yields the absorbance of the sample. The phosphorus content of the sample is obtained by subtracting the two absorbance values. This method eliminates the need for manual operation, reduces sample usage, and decreases the number of tests required, making it more suitable for fully automated total phosphorus analyzers and unmanned laboratories.

[0026] Based on this, firstly, referring to Figure 2 This application provides an automatically compensated method for determining total phosphorus based on ammonium molybdate spectrophotometry, comprising: The sample was digested with potassium persulfate to obtain the first liquid; Add ascorbic acid to the first liquid to obtain the second liquid; Adding sulfuric acid to the second liquid yields a third liquid; The first absorbance is obtained by colorimetric measurement of the third liquid; Adding molybdate to the third liquid yields a fourth liquid; The fourth liquid was subjected to colorimetric measurement to obtain a second absorbance; The phosphorus content of the sample is obtained based on the first absorbance and the second absorbance.

[0027] In the application provided by this invention, ascorbic acid and sulfuric acid are first added to the sample liquid to simulate the state of adding turbidity-color compensation solution (a mixture of sulfuric acid and ascorbic acid). After colorimetric analysis under this state, the colorimetric result of the reference sample—the first absorbance—is obtained. Then, molybdate is added for color development, and a second colorimetric analysis is performed to obtain the second absorbance. The state after adding molybdate is also the state of the sample test corresponding to the national standard procedure.

[0028] In one embodiment, obtaining the phosphorus content of the sample based on the first absorbance and the second absorbance includes: subtracting the first absorbance from the second absorbance to obtain a third absorbance, and obtaining the phosphorus content based on the third absorbance according to a working curve. By subtracting the first absorbance, interference from turbidity and color in the sample on colorimetric detection can be removed. In some embodiments, the subtraction of the first absorbance also needs to consider the effect of the sample volume consumed in the first colorimetric test. In other embodiments, when the sample volume consumed in the first colorimetric test is small, the subtraction of the first absorbance does not need to consider the effect of the sample volume consumed in the first colorimetric test, because experimental results show that the effect of a small sample volume consumed in the first colorimetric test is negligible.

[0029] In one embodiment, the volume of the third liquid used for colorimetric measurement is smaller than the volume of the fourth liquid used for colorimetric measurement. Preferably, the ratio of the volume of the third liquid used for colorimetric measurement to the volume of the fourth liquid used for colorimetric measurement is 5:8. When the sample volume consumed in the first colorimetric measurement is small, i.e., the amount of the third liquid used is small, the impact on the subsequent second colorimetric measurement can be further reduced.

[0030] In one embodiment, the sulfuric acid added to the second liquid is a 1:1 sulfuric acid solution.

[0031] In one embodiment, the molybdate added to the third liquid is a solution of ammonium molybdate and potassium antimony tartrate dissolved in water. While the aforementioned national standard includes sulfuric acid in the molybdate solution, since sulfuric acid has already been added before the first colorimetric analysis, it is unnecessary to add sulfuric acid again during the preparation of the molybdate in the method of this application.

[0032] In one embodiment, the first liquid is diluted with water to a fixed volume before ascorbic acid is added to the first liquid.

[0033] In one embodiment, after adding ascorbic acid to the first liquid, at least 30 seconds are elapsed before adding sulfuric acid to the second liquid. The ascorbic acid and sulfuric acid added before the first colorimetric measurement act as turbidity-color compensation solutions, but they cannot be added at the same time because: ① Ascorbic acid (reducing agent) is added first in the standard to ensure the reaction proceeds under preset conditions; ② Sulfuric acid (1:1) is a strong acid, and mixing it with ascorbic acid can easily destroy the molecular structure of ascorbic acid; ③ The volumes of the two added are inconsistent.

[0034] In one embodiment, reference Figure 3 The specific method is as follows: Add 4 mL of potassium persulfate to the sample, seal the graduated tube tightly, and secure the glass stopper with a small piece of cloth and thread. Place the tube in a large beaker and heat it in an autoclave. When the pressure reaches 1.1 kg / cm² and the corresponding temperature is 120°C, maintain this temperature for 30 minutes, then stop heating to allow digestion. After the pressure gauge reading drops to zero, remove the tube and allow it to cool. Then dilute with water to the mark. Add 1 mL of ascorbic acid solution to the digest and mix well. After 30 seconds, add 1.2 mL of sulfuric acid and mix thoroughly. Using a 30 mm path length cuvette, measure the absorbance at 700 nm wavelength with water as a reference. Add 0.8 mL of molybdate solution to each digest and mix thoroughly. After standing at room temperature for 15 minutes, use a 30 mm path length cuvette to measure the absorbance at 700 nm wavelength with water as a reference. Subtract the absorbance of the blank test and find the phosphorus content from the working curve.

[0035] In one embodiment, the molybdate solution was prepared by dissolving 13g of ammonium molybdate in 100mL of water and dissolving 0.35g of potassium antimony tartrate in 100mL of water, and then mixing the two solutions thoroughly.

[0036] This application provides a dynamic adaptive ultraviolet differential spectroscopy measurement method based on parameter feedback. By adding ascorbic acid and sulfuric acid for pre-colorimetric analysis, the absorbance of a blank test can be obtained. Further addition of molybdate yields the absorbance of the sample. Subtraction between the two absorbance values ​​yields the phosphorus content of the sample. This method eliminates the need for manual operation, reduces sample usage, and decreases the number of tests required, making it better suited for fully automated total phosphorus analyzers and unmanned laboratories.

[0037] Secondly, embodiments of this application also provide an automatically compensated total phosphorus determination device based on ammonium molybdate spectrophotometry, such as... Figure 4 As shown, it includes: The digestion module is used to digest the sample by adding potassium persulfate to obtain the first liquid; An ascorbic acid addition module is used to add ascorbic acid to the first liquid to obtain a second liquid; A sulfuric acid addition module is used to add sulfuric acid to the second liquid to obtain a third liquid; The first colorimetric module is used to perform colorimetric measurements on the third liquid to obtain a first absorbance; A molybdate addition module is used to add molybdate to the third liquid to obtain a fourth liquid; The second colorimetric module is used to perform colorimetric measurements on the fourth liquid to obtain a second absorbance; The result acquisition module is used to obtain the phosphorus content of the sample based on the first absorbance and the second absorbance.

[0038] The specific functions of the total phosphorus determination device based on ammonium molybdate spectrophotometry with automatic compensation can be found in the various embodiments of the total phosphorus determination method based on ammonium molybdate spectrophotometry with automatic compensation in this application, and will not be repeated here.

[0039] In one embodiment, the first colorimetric module and the second colorimetric module are the same module, and / or at least two of the ascorbic acid addition module, sulfuric acid addition module, and molybdate addition module are the same module. This allows for automated experiments with fewer modules.

[0040] Thirdly, embodiments of this application provide a total phosphorus determination system based on ammonium molybdate spectrophotometry with automatic compensation. This system may include an electronic device for performing the total phosphorus determination method based on ammonium molybdate spectrophotometry with automatic compensation as described in the first aspect. The electronic device may be a personal computer (PC), a laptop computer, a server, or other device with data processing capabilities.

[0041] In this embodiment of the application, the electronic device may include a processor, a memory, a communication interface, and a communication bus.

[0042] The communication bus can be of any type and is used to interconnect the processor, memory, and communication interface.

[0043] Communication interfaces include input / output (I / O) interfaces, physical interfaces, and logical interfaces used to interconnect devices within an electronic device, as well as interfaces used to interconnect the electronic device with other devices (such as other computing devices or user equipment). Physical interfaces can be Ethernet interfaces, fiber optic interfaces, ATM interfaces, etc.; user equipment can be displays, keyboards, etc.

[0044] Memory can be various types of storage media, such as random access memory (RAM), read-only memory (ROM), non-volatile RAM (NVRAM), flash memory, optical storage, hard disk, programmable ROM (PROM), erasable PROM (EPROM), electrically erasable PROM (EEPROM), etc.

[0045] The processor can be a general-purpose processor, which can call the total phosphorus determination program based on ammonium molybdate spectrophotometry with automatic compensation stored in the memory and execute the total phosphorus determination method based on ammonium molybdate spectrophotometry with automatic compensation provided in the embodiments of this application. For example, the general-purpose processor can be a central processing unit (CPU). The method executed when the total phosphorus determination program based on ammonium molybdate spectrophotometry with automatic compensation is called can refer to the various embodiments of the total phosphorus determination method based on ammonium molybdate spectrophotometry with automatic compensation provided in this application, and will not be repeated here.

[0046] Fourthly, embodiments of this application also provide a readable storage medium.

[0047] This application stores a total phosphorus determination program based on ammonium molybdate spectrophotometry with automatic compensation on a readable storage medium, wherein when the total phosphorus determination program based on ammonium molybdate spectrophotometry with automatic compensation is executed by a processor, the steps of the total phosphorus determination method based on ammonium molybdate spectrophotometry with automatic compensation as described above are implemented.

[0048] The method implemented when the total phosphorus determination procedure based on ammonium molybdate spectrophotometry with automatic compensation is executed can be referred to in the various embodiments of the total phosphorus determination method based on ammonium molybdate spectrophotometry with automatic compensation in this application, and will not be repeated here.

[0049] It should be noted that the sequence numbers of the embodiments in this application are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0050] The terms "comprising" and "having," and any variations thereof, in the specification, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to such process, method, product, or apparatus. The terms "first," "second," and "third," etc., are used to distinguish different objects, etc., and do not indicate a sequence, nor do they limit "first," "second," and "third" to different types.

[0051] In the description of the embodiments of this application, terms such as "exemplary," "for example," or "for instance" are used to indicate examples, illustrations, or explanations. Any embodiment or design described as "exemplary," "for example," or "for instance" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of terms such as "exemplary," "for example," or "for instance" is intended to present the relevant concepts in a concrete manner.

[0052] In the description of the embodiments of this application, unless otherwise stated, " / " means "or". For example, A / B can mean A or B. The "and / or" in the text is merely a description of the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist simultaneously, and B exists alone. In addition, in the description of the embodiments of this application, "multiple" means two or more.

[0053] In some processes described in the embodiments of this application, multiple operations or steps are included in a specific order. However, it should be understood that these operations or steps may not be executed in the order they appear in the embodiments of this application, or they may be executed in parallel. The sequence number of the operation is only used to distinguish different operations, and the sequence number itself does not represent any execution order. In addition, these processes may include more or fewer operations, and these operations or steps may be executed sequentially or in parallel, and these operations or steps may be combined.

[0054] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) as described above, and includes several instructions to cause a terminal device to execute the methods described in the various embodiments of this application.

[0055] The above are merely preferred embodiments of this application and do not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. A method for determining total phosphorus based on ammonium molybdate spectrophotometry with automatic compensation, characterized in that, include: The sample was digested with potassium persulfate to obtain the first liquid; Add ascorbic acid to the first liquid to obtain the second liquid; Adding sulfuric acid to the second liquid yields a third liquid; The first absorbance is obtained by colorimetric measurement of the third liquid; Adding molybdate to the third liquid yields a fourth liquid; The fourth liquid was subjected to colorimetric measurement to obtain a second absorbance; The phosphorus content of the sample is obtained based on the first absorbance and the second absorbance.

2. The method as described in claim 1, characterized in that, The step of obtaining the phosphorus content of the sample based on the first absorbance and the second absorbance includes: The third absorbance is obtained by subtracting the first absorbance from the second absorbance, and the phosphorus content is obtained by using the third absorbance according to the working curve.

3. The method as described in claim 1, characterized in that, The volume of the third liquid used for colorimetric measurement is smaller than the volume of the fourth liquid used for colorimetric measurement.

4. The method as described in claim 3, characterized in that, The ratio of the volume of the third liquid used for colorimetric measurement to the volume of the fourth liquid used for colorimetric measurement is 5:

8.

5. The method as described in claim 1, characterized in that, In the addition of sulfuric acid to the second liquid, the added sulfuric acid is a 1:1 sulfuric acid solution.

6. The method as described in claim 1, characterized in that, In the addition of the third liquid to the molybdate, the added molybdate is a solution of ammonium molybdate and potassium antimony tartrate dissolved in water.

7. The method as described in claim 1, characterized in that, Before adding ascorbic acid to the first liquid, the first liquid is diluted with water to a fixed volume.

8. The method as described in claim 1, characterized in that, After adding ascorbic acid to the first liquid, wait at least 30 seconds before adding sulfuric acid to the second liquid.

9. A total phosphorus determination device with automatic compensation based on ammonium molybdate spectrophotometry, characterized in that, include: The digestion module is used to digest the sample by adding potassium persulfate to obtain the first liquid; An ascorbic acid addition module is used to add ascorbic acid to the first liquid to obtain a second liquid; A sulfuric acid addition module is used to add sulfuric acid to the second liquid to obtain a third liquid; The first colorimetric module is used to perform colorimetric measurements on the third liquid to obtain a first absorbance; A molybdate addition module is used to add molybdate to the third liquid to obtain a fourth liquid; The second colorimetric module is used to perform colorimetric measurements on the fourth liquid to obtain a second absorbance; The result acquisition module is used to obtain the phosphorus content of the sample based on the first absorbance and the second absorbance.

10. The apparatus as claimed in claim 9, characterized in that, The first colorimetric module and the second colorimetric module are the same module, and / or at least two of the ascorbic acid addition module, sulfuric acid addition module, and molybdate addition module are the same module.

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