Environment-friendly phosphate detection reagent group and preparation method and application thereof

Abstract

The application belongs to the technical field of water quality detection, and relates to an environment-friendly phosphate detection reagent group and a preparation method and application thereof. The environment-friendly phosphate detection reagent group comprises reagent one and reagent two which are independently stored, and the preparation water of the reagent one and the reagent two is purified water which is boiled and cooled. The reagent one is a water solution of a reducing compound stabilizer which is compounded by a reducing reagent and an antioxidant stabilizing aid. The reagent two is a non-antimony modified molybdate acid color developing solution which is compounded by a molybdate compound, a non-antimony complex modified aid and an acid solvent. The environment-friendly phosphate detection reagent group provided by the application discards toxic antimony aids, is non-toxic and harmless and has no secondary pollution, and has the characteristics of simple preparation process, small reagent consumption, low detection cost, long reagent shelf life and rapid color developing reaction, and can be widely applied to phosphate detection of various water bodies such as surface water, domestic sewage and industrial wastewater.

Description

Technical Field

[0001] This application belongs to the field of water quality testing technology, and relates to a phosphate detection reagent, and more particularly to an environmentally friendly phosphate detection reagent kit and its preparation method and application. Background Technology

[0002] Phosphate is a key indicator for assessing the eutrophication level of water bodies. With the rapid development of my country's economy and society, the discharge of phosphorus-containing wastewater, such as industrial wastewater and domestic sewage, has continued to increase, leading to frequent instances of excessive phosphate concentrations in natural water bodies. Excessive phosphate levels in water bodies can trigger massive algal blooms, causing eutrophication, disrupting the balance of aquatic ecosystems, and seriously threatening drinking water safety and aquatic environmental health. Therefore, accurate and rapid determination of phosphate levels in water bodies is of significant practical importance for water environment monitoring, pollution early warning and control, and ecological environmental protection.

[0003] Currently, the mainstream method for determining phosphate in water both domestically and internationally is the molybdenum-antimony anti-phosphate spectrophotometric method. This method is widely used in various water quality testing scenarios due to its advantages such as simple operation, widespread availability of instruments, and accurate and reliable results. It is also the phosphate detection method specified in national standards. The basic principle of this method is as follows: under acidic conditions, orthophosphate reacts with ammonium molybdate and potassium antimony tartrate to form phosphomolybdic heteropolyacid, which is then reduced by ascorbic acid to a blue phosphomolybdic blue complex. The absorbance is measured at a specific wavelength to quantitatively calculate the phosphate content.

[0004] However, the aforementioned traditional detection methods still have many problems in practical applications. First, traditional methods generally use potassium antimony tartrate as a complexing catalyst. Antimony is a heavy metal element with certain biotoxicity and cumulative properties. Direct discharge of the detection waste liquid will cause serious secondary environmental pollution, which is inconsistent with the current development concept of green chemistry and ecological environmental protection. Second, traditional methods use ascorbic acid as a reducing agent, but its aqueous solution has poor stability and is easily oxidized and degraded by oxygen in the air at room temperature. It usually needs to be prepared fresh or stored at low temperature, which not only increases the complexity of the detection operation, but also increases the cost of reagent storage and transportation.

[0005] Furthermore, traditional testing methods consume relatively large amounts of reagents, requiring a significant volume for each sample, which increases both testing costs and chemical waste. Additionally, commercially available conventional testing reagents generally have short shelf lives; prolonged storage leads to degradation of the active ingredients, resulting in inaccurate test results and affecting the accuracy and reliability of the data. While some improved reagents offer improvements in certain aspects, they often suffer from drawbacks such as long color development times, insufficient detection sensitivity, and limited applicability to different water types, making it difficult to simultaneously meet the multiple demands of environmental friendliness, stability, accuracy, and cost-effectiveness.

[0006] Therefore, how to develop an environmentally friendly, stable, rapid colorimetric reagent with low reagent consumption and long shelf life, while ensuring detection accuracy and further reducing detection costs and environmental pollution, has become an urgent problem to be solved by those skilled in the art. Summary of the Invention

[0007] In view of the shortcomings of the existing technology, the purpose of this application is to provide an environmentally friendly phosphate detection reagent kit, its preparation method and application, so as to achieve low-toxicity, rapid and accurate detection of phosphate in water.

[0008] To achieve this objective, the present application adopts the following technical solution: In a first aspect, this application provides an environmentally friendly phosphate detection reagent kit, comprising reagent one and reagent two stored independently, wherein the water used to prepare reagent one and reagent two is purified water that has been boiled and then cooled.

[0009] The reagent one is a reducing composite stabilizer aqueous solution, which is composed of reducing agents and antioxidant stabilizing agents.

[0010] And / or, the second reagent is an antimony-free modified molybdate acidic colorimetric solution, which is composed of molybdate compound, antimony-free complexing modifier and acidic solvent.

[0011] And / or, the reducing agents include any one or more combinations of ascorbic acid, sodium bisulfite, thiosulfate, and glucose.

[0012] And / or, the antioxidant stabilizing agent includes any one or more combinations of disodium EDTA, sodium citrate, mannitol, and sodium pyrophosphate.

[0013] And / or, the mass concentration of the reducing agent in reagent one is 0.8%~1.2%.

[0014] And / or, the amount of antioxidant stabilizing agent added in reagent one is 0.01~0.1g / 100mL.

[0015] And / or, the molybdate compound includes any one or more combinations of ammonium molybdate tetrahydrate, sodium molybdate dihydrate, anhydrous ammonium molybdate, and ammonium heptamolybdate.

[0016] And / or, the antimony-free complexing modifier includes any one or more combinations of sodium tartrate, potassium hydrogen tartrate, citric acid, oxalic acid, and sodium gluconate.

[0017] And / or, the acidic solvent includes any one or more combinations of dilute sulfuric acid, low-concentration perchloric acid, glacial acetic acid, phosphoric acid, and formic acid.

[0018] And / or, the mass concentration of the molybdate compound in reagent two is 1% to 3%.

[0019] And / or, the mass concentration of the antimony-free complexing modifier in reagent two is 0.05%~0.1%.

[0020] And / or, the volume concentration of the acidic solvent in reagent two is 15% to 35%.

[0021] Secondly, this application provides a method for preparing an environmentally friendly phosphate detection reagent kit as described in the first aspect, comprising the following steps: (1) Select purified water for boiling to remove oxygen, and after naturally cooling to room temperature, add reducing agents and antioxidant stabilizing agents in sequence, and stir at a constant speed until the solid is completely dissolved to obtain reagent one, which is then sealed and stored away from light. (2) Pre-treat purified water to remove dissolved oxygen and impurities, prepare an acidic solvent, add molybdate compound and antimony-free complexing modifier to the acidic solvent in sequence, stir at constant temperature until completely dissolved, use pre-treated purified water to make up the volume, let stand at room temperature in the dark to age, and obtain concentrated stock solution of reagent 2, which is then sealed and stored.

[0022] Steps (1) and (2) are not in any particular order.

[0023] And / or, the concentrated stock solution of reagent two in step (2) is used after being diluted with purified water, with a dilution ratio of 20 to 30 times.

[0024] Thirdly, this application provides a method for detecting phosphate in water using the environmentally friendly phosphate detection reagent kit as described in the first aspect, comprising the following steps: S1. Sampling: Measure the water sample to be tested and place it in a colorimetric tube; S2. Adding reagents: Add quantitative reagent one and diluted reagent two to the water sample in sequence; S3. Mix well: Vigorously shake the colorimetric tube to thoroughly mix the reagent with the water sample; S4. Color development and standing: Let the reaction stand at room temperature and pressure; S5. Detection: The absorbance of the solution is measured using a spectrophotometer to complete the detection of phosphate content.

[0025] And / or, the sample volume of the water sample to be tested in step S1 is 4~6 mL.

[0026] And / or, the single addition volume of reagent one and diluted reagent two in step S2 is 0.8~1.2 mL.

[0027] And / or, the settling time in step S4 is 4 to 6 minutes.

[0028] And / or, the wavelength for measuring the absorbance of the solution in step S5 is 690~710nm.

[0029] Compared with the prior art, this application has the following advantages: (1) The phosphate detection reagent kit provided in this application uses antimony-free complexing modifier to replace traditional potassium antimony tartrate, completely avoiding the toxic pollution caused by heavy metal antimony. It is non-toxic and harmless as a whole. The reaction waste liquid can be simply treated and discharged, and will not cause secondary pollution to water bodies. It is an environmentally friendly detection reagent.

[0030] (2) The phosphate detection reagent kit provided in this application is a combination of reducing agents and antioxidant stabilizing agents. The antioxidant stabilizing agents can effectively inhibit the oxidation and deterioration of reducing components, enhance the stability of reagent aqueous solution, extend the overall shelf life of the reagent, and extend the shelf life at room temperature by more than 30% compared with traditional national standard reagents. It does not require low-temperature refrigeration and is convenient to transport and use.

[0031] (3) The phosphate detection reagent kit provided in this application adopts a low-volume concentration system, with a small amount of reagent used and a low consumption of reagent per test. It can still meet the national standard detection accuracy under extremely low reagent consumption conditions, greatly reducing the cost of consumables per test and having good economic benefits.

[0032] (4) The phosphate detection reagent kit provided in this application has a fast colorimetric reaction speed. It only takes 4 to 6 minutes to complete the colorimetric reaction under normal temperature conditions. The detection process does not require auxiliary equipment such as heating, light blocking, or constant temperature. The operation procedure is simple and the detection efficiency is high. It is suitable for rapid screening of large batches of water samples and emergency monitoring scenarios.

[0033] (5) The phosphate detection reagent kit provided in this application has high detection accuracy, with a relative detection error of ≤3%. The detection repeatability and accuracy meet the national water quality testing standards and are suitable for phosphate detection in various types of water bodies such as surface water, domestic sewage, and industrial wastewater. Detailed Implementation

[0034] The technical solution of this application will be further described below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely to help understand this application and should not be regarded as specific limitations on this application.

[0035] One embodiment of this application provides an environmentally friendly phosphate detection reagent kit, including reagent one and reagent two stored independently, wherein the water used to prepare reagent one and reagent two is purified water that has been boiled and then cooled.

[0036] The reagent one is a reducing composite stabilizer aqueous solution, which is composed of reducing agents and antioxidant stabilizing agents.

[0037] In some embodiments, the second reagent is an antimony-free modified molybdate acidic colorimetric solution, which is composed of a molybdate compound, an antimony-free complexing modifier, and an acidic solvent.

[0038] In some embodiments, the reducing agent includes any one or more combinations of ascorbic acid, sodium bisulfite, thiosulfate, and glucose, preferably glucose, including glucose monohydrate, anhydrous glucose, and dextrorotatory glucose, with glucose monohydrate being more preferred.

[0039] Among them, glucose monohydrate has excellent water solubility and mild reducing properties. It does not produce impurities or toxic residues in acidic molybdate systems, is environmentally friendly and does not cause secondary pollution. It is suitable for the preparation requirements of reagent one, and has stronger storage stability than other sugar additives. It can be used with antioxidant stabilizing additives to further extend the shelf life of the reagent.

[0040] In some embodiments, the antioxidant stabilizing agent includes any one or more combinations of disodium EDTA, sodium citrate, mannitol, and sodium pyrophosphate, preferably disodium EDTA.

[0041] Disodium EDTA can effectively inhibit the oxidation and deterioration of reducing components, enhance the stability of reagent aqueous solutions, and extend the overall shelf life of reagents.

[0042] In some embodiments, the mass concentration of the reducing agent in reagent one is 0.8% to 1.2%, for example, it can be 0.8%, 0.84%, 0.88%, 0.92%, 0.96%, 1.0%, 1.04%, 1.08%, 1.12%, 1.16% or 1.2%, but it is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0043] In some embodiments, the amount of antioxidant stabilizer added in reagent one is 0.01~0.1g / 100mL, for example, it can be 0.01g / 100mL, 0.02g / 100mL, 0.03g / 100mL, 0.04g / 100mL, 0.05g / 100mL, 0.06g / 100mL, 0.07g / 100mL, 0.08g / 100mL, 0.09g / 100mL or 0.1g / 100mL, but is not limited to the listed values, other unlisted values ​​within this range are also applicable.

[0044] In some embodiments, the molybdate compound includes any one or more combinations of ammonium molybdate tetrahydrate, sodium molybdate dihydrate, anhydrous ammonium molybdate, and ammonium heptamolybdate, preferably anhydrous ammonium molybdate.

[0045] Among them, anhydrous ammonium molybdate dissolves rapidly in dilute sulfuric acid systems, exhibits high stability of its colorimetric complexes, and has extremely low interference from impurities, making it the optimal molybdate raw material for water phosphate detection.

[0046] In some embodiments, the antimony-free complexing modifier includes any one or more combinations of sodium tartrate, potassium hydrogen tartrate, citric acid, oxalic acid, and sodium gluconate, preferably sodium tartrate.

[0047] Sodium tartrate has a complexing ability close to that of potassium antimony tartrate, which can stabilize molybdenum-phosphorus colorimetric complexes. It is free of heavy metal toxicity, has good water solubility, and is suitable for acidic detection systems. It is the best environmentally friendly modifier to replace antimony salts, completely avoiding the toxic pollution caused by heavy metal antimony.

[0048] In some embodiments, the acidic solvent includes any one or more combinations of dilute sulfuric acid, low-concentration perchloric acid, glacial acetic acid, phosphoric acid, and formic acid, preferably dilute acetic acid.

[0049] Among them, dilute acetic acid has controllable acidity, few impurities, and strong stability. It is a dedicated acidic medium for the molybdenum antimony phosphate colorimetric system, does not produce side reactions, and has the highest cost performance and the best compatibility.

[0050] In some embodiments, the mass concentration of the molybdate compound in reagent two is 1% to 3%, for example, it can be 1%, 1.2%, 1.4%, 1.6%, 1.8%, 2%, 2.2%, 2.4%, 2.6%, 2.8% or 3%, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0051] In some embodiments, the mass concentration of the antimony-free complexing modifier in reagent two is 0.05% to 0.1%, for example, it can be 0.05%, 0.06%, 0.07%, 0.08%, 0.09% or 0.1%, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0052] In some embodiments, the volume concentration of the acidic solvent in the second reagent is 15% to 35%, for example, it can be 15%, 17%, 19%, 21%, 23%, 25%, 27%, 29%, 31%, 33% or 35%, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0053] One embodiment of this application also provides a method for preparing the environmentally friendly phosphate detection reagent kit described in any of the above embodiments, comprising the following steps: (1) Select purified water for boiling to remove oxygen, and after naturally cooling to room temperature, add reducing agents and antioxidant stabilizing agents in sequence, and stir at a constant speed until the solid is completely dissolved to obtain reagent one, which is then sealed and stored away from light. (2) Pre-treat purified water to remove dissolved oxygen and impurities, prepare an acidic solvent, add molybdate compound and antimony-free complexing modifier to the acidic solvent in sequence, stir at constant temperature until completely dissolved, use pre-treated purified water to make up the volume, let stand at room temperature in the dark to age, and obtain concentrated stock solution of reagent 2, which is then sealed and stored.

[0054] Steps (1) and (2) are not in any particular order.

[0055] The room temperature mentioned in this application is specifically 20~30℃, for example, it can be 20℃, 21℃, 22℃, 23℃, 24℃, 25℃, 26℃, 27℃, 28℃, 29℃ or 30℃, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0056] In some embodiments, the concentrated stock solution of reagent two in step (2) is used after being diluted with purified water at a dilution ratio of 20 to 30 times, for example, 20 times, 21 times, 22 times, 23 times, 24 times, 25 times, 26 times, 27 times, 28 times, 29 times or 30 times, but not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0057] The above-mentioned concentrated stock solution design can effectively reduce storage volume and transportation costs.

[0058] For example, the acidic solvent is glacial acetic acid, and the specific preparation method is as follows: glacial acetic acid and purified water are mixed in a certain proportion to prepare a dilute acetic acid solution with a volume concentration controlled at 45%~55%, for example, it can be 45%, 46%, 47%, 48%, 49%, 50%, 51%, 52%, 53%, 54% or 55%, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0059] One embodiment of this application also provides a method for detecting phosphate in water using the environmentally friendly phosphate detection reagent kit described in any of the above embodiments, comprising the following steps: S1. Sampling: Measure the water sample to be tested and place it in a colorimetric tube; S2. Adding reagents: Add quantitative reagent one and diluted reagent two to the water sample in sequence; S3. Mix well: Vigorously shake the colorimetric tube to thoroughly mix the reagent with the water sample; S4. Color development and standing: Let the reaction stand at room temperature and pressure; S5. Detection: The absorbance of the solution is measured using a spectrophotometer to complete the detection of phosphate content.

[0060] In some embodiments, the sample volume of the water sample to be tested in step S1 is 4 to 6 mL, for example, it can be 4 mL, 4.2 mL, 4.4 mL, 4.6 mL, 4.8 mL, 5 mL, 5.2 mL, 5.4 mL, 5.6 mL, 5.8 mL or 6 mL, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0061] In some embodiments, the single-addition volume of reagent one and diluted reagent two in step S2 is 0.8~1.2 mL, for example, it can be 0.8 mL, 0.84 mL, 0.88 mL, 0.92 mL, 0.96 mL, 1.0 mL, 1.04 mL, 1.08 mL, 1.12 mL, 1.16 mL or 1.2 mL, but it is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0062] In some embodiments, the settling reaction time in step S4 is 4 to 6 minutes, for example, 4 minutes, 4.2 minutes, 4.4 minutes, 4.6 minutes, 4.8 minutes, 5 minutes, 5.2 minutes, 5.4 minutes, 5.6 minutes, 5.8 minutes or 6 minutes, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0063] In some embodiments, the wavelength for measuring the absorbance of the solution in step S5 is 690~710nm, for example, it can be 690nm, 692nm, 694nm, 696nm, 698nm, 700nm, 702nm, 704nm, 706nm, 708nm or 710nm, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0064] The numerical range described in this application includes not only the point values ​​listed above, but also any point values ​​between the above numerical ranges that are not listed. Due to space limitations and for the sake of brevity, this application will not exhaustively list the specific point values ​​included in the range.

[0065] Example 1 This embodiment provides an environmentally friendly phosphate detection reagent kit, including reagent one and reagent two, and the specific preparation method is as follows: (1) Select purified water for deoxygenation treatment by boiling and then cool it naturally to room temperature; weigh 1.0g glucose monohydrate and 0.05g disodium EDTA, add an appropriate amount of purified water after boiling and cooling and stir until completely dissolved, transfer to a 100mL volumetric flask, and dilute to the mark with purified water after boiling and cooling, shake well to obtain a mixed solution containing 1.0% glucose monohydrate and 0.05g / 100mL disodium EDTA, i.e., reagent one, and store it at room temperature in a sealed container protected from light.

[0066] (2) Boil purified water to remove oxygen and then cool it for later use; mix glacial acetic acid with purified water to prepare a 50% dilute acetic acid solution; weigh 15g of anhydrous ammonium molybdate and 2.0g of sodium tartrate, add 300mL of 50% dilute acetic acid solution, and stir at a constant temperature until completely dissolved; transfer to a 500mL volumetric flask, dilute to the mark with pretreated purified water, and shake well; let stand at room temperature in the dark for 24h to obtain the concentrated stock solution of reagent II, and store it in a sealed container. Before testing, dilute the concentrated stock solution 25 times with purified water to obtain reagent II.

[0067] Example 2 This embodiment provides an environmentally friendly phosphate detection reagent kit, including reagent one and reagent two, and the specific preparation method is as follows: (1) Select purified water for deoxygenation treatment by boiling and let it cool naturally to room temperature; weigh 0.8g ascorbic acid and 0.01g sodium citrate, add an appropriate amount of purified water after boiling and cooling and stir until completely dissolved, transfer to a 100mL volumetric flask, dilute to the mark with purified water after boiling and cooling, shake well, and obtain a mixed solution containing 0.8% ascorbic acid and 0.01g / 100mL sodium citrate, i.e., reagent one, which should be stored at room temperature in a sealed container protected from light.

[0068] (2) Boil purified water to remove oxygen and then cool it for later use; mix glacial acetic acid with purified water to prepare a 45% dilute acetic acid solution; weigh 13g of ammonium molybdate tetrahydrate and 1.8g of citric acid, add them to 280mL of 45% dilute acetic acid solution, and stir at a constant temperature until completely dissolved; transfer to a 450mL volumetric flask, dilute to the mark with pretreated purified water, and shake well; let stand at room temperature in the dark for 24h to obtain the concentrated stock solution of reagent II, and store it in a sealed container. Before testing, dilute the concentrated stock solution 20 times with purified water to obtain reagent II.

[0069] Example 3 This embodiment provides an environmentally friendly phosphate detection reagent kit, including reagent one and reagent two, and the specific preparation method is as follows: (1) Select purified water for deoxygenation treatment by boiling and cool it naturally to room temperature; weigh 1.2g of anhydrous glucose and 0.1g of sodium pyrophosphate, add an appropriate amount of purified water after boiling and cooling and stir until completely dissolved, transfer to a 100mL volumetric flask, dilute to the mark with purified water after boiling and cooling, shake well, and obtain a mixed solution containing 1.2% anhydrous glucose and 0.1g / 100mL sodium pyrophosphate, i.e., reagent one, which should be stored at room temperature in a sealed container protected from light.

[0070] (2) Boil purified water to remove oxygen and then cool it for later use; mix glacial acetic acid with purified water to prepare a 55% dilute acetic acid solution; weigh 18g of ammonium heptamolybdate and 2.5g of sodium gluconate, add them to 320mL of 55% dilute acetic acid solution, and stir at a constant temperature until completely dissolved; transfer to a 550mL volumetric flask, dilute to the mark with pretreated purified water, and shake well; let stand at room temperature in the dark for 24h to obtain the concentrated stock solution of reagent II, and store it in a sealed container. Before testing, dilute the concentrated stock solution 30 times with purified water to obtain reagent II.

[0071] Comparative Example 1 This comparative example provides a phosphate detection reagent, which differs from Example 1 in that potassium antimony tartrate is used instead of sodium tartrate in reagent 2. The remaining components and preparation methods are the same as in Example 1, so they will not be described in detail here.

[0072] Comparative Example 2 This comparative example provides a phosphate detection reagent, which differs from Example 1 in that: EDTA disodium is not added to the reagent, while the remaining components and preparation method are the same as in Example 1, so they will not be described in detail here.

[0073] Application Example 1 This application example uses the phosphate detection reagent kit prepared in Example 1 to detect phosphate in water quality. The operation steps are as follows: S1. Sampling: Measure 5 mL of 0.5 mg / L phosphate standard working solution as the water sample to be tested and place it in a colorimetric tube; S2. Adding reagents: Add 1 mL of reagent one and 1 mL of diluted reagent two to the water sample in sequence. S3. Mix well: Vigorously shake the colorimetric tube to thoroughly mix the reagent with the water sample; S4. Color development and standing: Let the reaction stand at room temperature and pressure for 5 minutes; S5. Detection: Using a blank reagent solution as a reference, the absorbance is measured at a wavelength of 690~710nm using a spectrophotometer, and the phosphate content in the water sample is calculated by combining the standard curve.

[0074] Application Example 2 This application example uses the phosphate detection reagent kit prepared in Example 2 to detect phosphate in water quality. The operation steps are as follows: S1. Sampling: Measure 4 mL of surface water as the water sample to be tested and place it in a colorimetric tube; S2. Adding reagents: Add 0.8 mL of reagent one and 0.8 mL of diluted reagent two to the water sample in sequence. S3. Mix well: Vigorously shake the colorimetric tube to thoroughly mix the reagent with the water sample; S4. Color development and standing: Let the reaction stand at room temperature and pressure for 4 minutes; S5. Detection: Using a blank reagent solution as a reference, the absorbance is measured at a wavelength of 690~710nm using a spectrophotometer, and the phosphate content in the water sample is calculated by combining the standard curve.

[0075] Application Example 3 This application example uses the phosphate detection reagent kit prepared in Example 3 to detect phosphate in water quality. The operation steps are as follows: S1. Sampling: Measure 6 mL of industrial wastewater as the water sample to be tested and place it in a colorimetric tube; S2. Adding reagents: Add 1.2 mL of reagent one and 1.2 mL of diluted reagent two to the water sample in sequence; S3. Mix well: Vigorously shake the colorimetric tube to thoroughly mix the reagent with the water sample; S4. Color development and standing: Let the reaction stand at room temperature and pressure for 6 minutes; S5. Detection: Using a blank reagent solution as a reference, the absorbance is measured at a wavelength of 690~710nm using a spectrophotometer, and the phosphate content in the water sample is calculated by combining the standard curve.

[0076] Comparative Application Example 1 This comparative application example uses the phosphate detection reagent prepared in Comparative Example 1 to detect phosphate in water quality. The operation steps are the same as in Application Example 1, so they will not be repeated here.

[0077] Comparative Application Example 2 This comparative application example uses the phosphate detection reagent prepared in Comparative Example 2 to detect phosphate in water quality. The operation steps are the same as in Application Example 1, so they will not be repeated here.

[0078] Performance testing (1) Color development speed: The time it takes for the absorbance to reach its maximum value and remain stable is called the color development time. The shorter the time, the faster the color development speed.

[0079] (2) Detection accuracy: Six parallel measurements were performed on the water sample to be tested, and the relative error was calculated.

[0080] (3) Reagent stability: After the reagent was stored at room temperature in a sealed container for 3 months, the same water sample was tested for phosphate and the rate of change of absorbance was measured.

[0081] The test results of Application Examples 1-3 and Comparative Application Examples 1-2 are detailed in Table 1 below.

[0082] Table 1 Furthermore, the reagent sets used in Application Examples 1-3 do not contain the heavy metal antimony, and the detection waste liquid has no antimony residue, which can be discharged after simple treatment; in contrast, the reagent used in Application Example 1 contains the heavy metal antimony, and the waste liquid needs to be specially treated. It can be seen that this application has significant environmentally friendly advantages.

[0083] The above description is only a specific embodiment of this application, but the protection scope of this application is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application fall within the protection and disclosure scope of this application.

Claims

1. An environmentally friendly phosphate detection reagent kit, characterized in that, The environmentally friendly phosphate detection reagent kit includes two reagents, which are stored independently. Both reagents are prepared with purified water that has been boiled and then cooled. Among them, the first reagent is a reducing composite stabilizer aqueous solution, which is composed of reducing agents and antioxidant stabilizing agents; And / or, the second reagent is an antimony-free modified molybdate acidic colorimetric solution, which is composed of molybdate compound, antimony-free complexing modifier and acidic solvent.

2. The environmentally friendly phosphate detection reagent kit according to claim 1, characterized in that, The reducing agents include any one or more combinations of ascorbic acid, sodium bisulfite, thiosulfate, and glucose. And / or, the antioxidant stabilizing agent includes any one or more combinations of disodium EDTA, sodium citrate, mannitol, and sodium pyrophosphate.

3. The environmentally friendly phosphate detection reagent kit according to claim 1, characterized in that, The mass concentration of the reducing agent in reagent one is 0.8%~1.2%; And / or, the amount of antioxidant stabilizing agent added in reagent one is 0.01~0.1g / 100mL.

4. The environmentally friendly phosphate detection reagent kit according to claim 1, characterized in that, The molybdate compound includes any one or more combinations of ammonium molybdate tetrahydrate, sodium molybdate dihydrate, anhydrous ammonium molybdate, and ammonium heptamolybdate. And / or, the antimony-free complexing modifier includes any one or more combinations of sodium tartrate, potassium hydrogen tartrate, citric acid, oxalic acid, and sodium gluconate; And / or, the acidic solvent includes any one or more combinations of dilute sulfuric acid, low-concentration perchloric acid, glacial acetic acid, phosphoric acid, and formic acid.

5. The environmentally friendly phosphate detection reagent kit according to claim 1, characterized in that, The mass concentration of the molybdate compound in reagent two is 1% to 3%; And / or, the mass concentration of the antimony-free complexing modifier in reagent two is 0.05%~0.1%; And / or, the volume concentration of the acidic solvent in reagent two is 15% to 35%.

6. A method for preparing an environmentally friendly phosphate detection reagent kit as described in any one of claims 1 to 5, characterized in that, The preparation method includes the following steps: (1) Select purified water for boiling to remove oxygen, and after naturally cooling to room temperature, add reducing agents and antioxidant stabilizing agents in sequence, and stir at a constant speed until the solid is completely dissolved to obtain reagent one, which is then sealed and stored away from light. (2) Pre-treat purified water to remove dissolved oxygen and impurities, prepare acidic solvent, add molybdate compound and antimony-free complexing modifier to acidic solvent in sequence, stir at constant temperature until completely dissolved, use pre-treated purified water to make up the volume, let stand at room temperature in the dark to age, and obtain concentrated stock solution of reagent 2, and store in a sealed container. Steps (1) and (2) are not in any particular order.

7. The preparation method of the environmentally friendly phosphate detection reagent kit according to claim 6, characterized in that, The concentrated stock solution of reagent 2 in step (2) is used after being diluted with purified water at a dilution ratio of 20 to 30 times.

8. A method for detecting phosphate in water quality using the environmentally friendly phosphate detection reagent kit as described in any one of claims 1 to 5, characterized in that, The method for detecting phosphate in water includes the following steps: S1. Sampling: Measure the water sample to be tested and place it in a colorimetric tube; S2. Adding reagents: Add quantitative reagent one and diluted reagent two to the water sample in sequence; S3. Mix well: Vigorously shake the colorimetric tube to thoroughly mix the reagent with the water sample; S4. Color development and standing: Let the reaction stand at room temperature and pressure; S5. Detection: The absorbance of the solution is measured using a spectrophotometer to complete the detection of phosphate content.

9. The method for detecting phosphate in water according to claim 8, characterized in that, The sample volume of the water to be tested in step S1 is 4~6 mL; And / or, the single addition volume of reagent one and diluted reagent two in step S2 is 0.8~1.2 mL.

10. The method for detecting phosphate in water according to claim 8 or 9, characterized in that, The settling time for step S4 is 4-6 minutes; And / or, the wavelength for measuring the absorbance of the solution in step S5 is 690~710nm.

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