Rapid detection reagent for total phosphorus in water and preparation method of rapid detection reagent

Abstract

The invention discloses a water quality total phosphorus rapid detection reagent and a preparation method thereof, and relates to the technical field of water quality total phosphorus detection, and the water quality total phosphorus rapid detection reagent comprises a digesting agent, a color developing reagent and a reducing reagent. Anhydrous ytterbium trifluoromethanesulfonate added into the color developing reagent can activate a polyethylene glycol diglycidyl ether epoxy group, the reaction time of the color developing reagent is shortened, ammonium molybdate tetrahydrate is added to dissociate high-purity molybdate to serve as a core active component of the reaction, polyethylene glycol diglycidyl ether and molybdate react accurately, and the purity of the molybdate is improved. Molybdate with a uniform structure is formed, and the storage stability is improved. According to the reduction reagent, through the synergistic effect between thiourea dioxide and an L-cysteine material, L-cysteine does not influence the directional reduction capacity of thiourea dioxide, and a reduction product of thiourea dioxide does not interfere the complexing function of L-cysteine, so that the reduction reagent has the advantages of efficient reduction and long-term stable preservation.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of water quality total phosphorus detection, in particular to a water quality total phosphorus rapid detection reagent and a preparation method thereof. BACKGROUND

[0002] The water quality total phosphorus rapid detection reagent is a chemical reagent combination for rapidly determining the total phosphorus content in water, and is mainly used in environmental monitoring, sewage treatment, surface water and groundwater detection and the like. Through simplifying the detection process and shortening the reaction time, the on-site or rapid laboratory analysis of the total phosphorus concentration is realized.

[0003] The accuracy of the existing water quality total phosphorus rapid detection reagent is easily affected by interfering substances, resulting in weakened accuracy of the water quality total phosphorus rapid detection. The water quality total phosphorus rapid detection reagent has a short storage time and is easily deteriorated due to environmental influence. The water quality total phosphorus rapid detection reagent has poor anti-interference ability, for example, the heavy metals, turbidity and colority in water can affect the result. Based on this, the present application provides a water quality total phosphorus rapid detection reagent and a preparation method thereof. SUMMARY

[0004] The main purpose of the present application is to provide a preparation method of a water quality total phosphorus rapid detection reagent with a long storage time and accurate detection result, which is applied to the preparation of the water quality total phosphorus rapid detection reagent.

[0005] In order to achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows: The present application provides a water quality total phosphorus rapid detection reagent, which comprises a digestion agent, a color developing reagent and a reducing reagent. The color developing reagent comprises the following components: ammonium molybdate tetrahydrate, polyethylene glycol diglycidyl ether, ytterbium triflate, a treatment liquid and ultrapure water. The mass ratio of the ammonium molybdate tetrahydrate, the polyethylene glycol diglycidyl ether, the treatment liquid, the ultrapure water and the ytterbium triflate is 19-21:9-11:676:166-168:1.

[0006] The epoxy value of the polyethylene glycol diglycidyl ether is 0.55-0.6 eq / 100g. The purity of the ammonium molybdate tetrahydrate is greater than or equal to 99.5%, ; Further, the preparation of the treatment liquid comprises the following steps: adding ultrapure water into a reaction kettle, passing nitrogen for 20 minutes at a flow rate of 50 mL / min, adding dilute sulfuric acid, adjusting the pH value to 3.6, adding ethylenediaminetetraacetic acid disodium and sodium bisulfite, and stirring magnetically at a speed of 300 rpm for 2 minutes to obtain the treatment liquid.

[0007] The dilute sulfuric acid has a concentration of 1 mol / L and is filtered through a 0.22-micron polytetrafluoroethylene filter membrane; Further, the mass ratio of the ultrapure water, the disodium ethylenediaminetetraacetate and the sodium bisulfite is 8000:2.4:1.

[0008] Further, the reducing agent comprises the following components: hydrosulfite, L-cysteine, dehydroascorbic acid, phosphate buffer, disodium ethylenediaminetetraacetate and ultrapure water; The mass ratio of the hydrosulfite, L-cysteine, dehydroascorbic acid, phosphate buffer, ultrapure water and disodium ethylenediaminetetraacetate is 10.9-12.9:36-36.6:17-17.8:27.8-29.8:9971:1.

[0009] Further, the preparation of the phosphate buffer comprises the following steps: adding potassium dihydrogen phosphate and dipotassium hydrogen phosphate into a reaction kettle, adding ultrapure water and stirring, the stirring speed is 100-160 rpm, stirring for 5 minutes, adding a pH value adjusting solution dropwise, adjusting the pH value to 8, and preparing the phosphate buffer.

[0010] Further, the mass ratio of the potassium dihydrogen phosphate and the dipotassium hydrogen phosphate is 1:5.18. The pH value adjusting solution is one of 1 mol / L sodium hydroxide solution and 1 mol / L hydrochloric acid solution.

[0011] Further, the preparation of the color developing reagent comprises the following steps: adding ammonium molybdate tetrahydrate into the treatment liquid in three equal portions and stirring, the stirring speed is 200-250 rpm, the interval is 5 minutes, after the third portion of the ammonium molybdate tetrahydrate is added, the stirring speed is increased to 300 rpm, adding polyethylene glycol diglycidyl ether dropwise and stirring, the stirring speed is 300 rpm, the dropwise adding rate is 1 drop per second, after the polyethylene glycol diglycidyl ether is completely added, adding ytterbium triflate and stirring, the stirring speed is 300 rpm, the temperature is controlled to be ≤28℃, the pH value is controlled to be 3.6, stirring for 2.5 hours, adding ultrapure water and stirring, the stirring speed is 150-200 rpm, stirring for 10 minutes, preparing a reaction liquid, filtering the reaction liquid through a mixed cellulose ester filter membrane, filtering out the precipitate, and preparing the color developing reagent.

[0012] The color developing reagent is suitable for detecting 0.01-5 mg / L total phosphorus. During the stirring process of adding the ytterbium triflate, the pH value is greater than 3.6, and a 0.1 mol / L sulfuric acid solution is added dropwise to adjust the pH value to 3.6. The color developing reagent needs to be packaged in a brown reagent bottle, and nitrogen gas is passed through the bottle for 10 minutes again before packaging, and the bottle opening is immediately sealed with a polytetrafluoroethylene plug. The pore size of the mixed cellulose ester filter membrane is 0.22 microns. Further, the preparation of the reducing agent comprises the following steps: adding phosphate buffer into a reaction kettle, passing nitrogen for 15 minutes at a flow rate of 50 mL / min, adding disodium ethylenediaminetetraacetate while stirring at a rotating speed of 200 rpm for 3 minutes to prepare a pretreatment solution, adding dehydroascorbic acid while stirring at a rotating speed of 150-200 rpm for 5-8 minutes, adding thiourea dioxide into the reaction kettle while stirring at a rotating speed of 180 rpm with an interval of 8 minutes, adding all the thiourea dioxide into the reaction kettle while stirring for 12 minutes, adding L-cysteine while stirring at a rotating speed of 200 rpm for 5 minutes, adding hydrochloric acid dropwise while stirring at a rotating speed of 150-200 rpm for 5-10 minutes to adjust the pH value to 3, adding ultrapure water while stirring at a rotating speed of 150-200 rpm for 10 minutes, and filtering out precipitates using a mixed cellulose ester filter membrane to prepare the reducing agent.

[0013] The pore size of the mixed cellulose ester filter membrane is 0.22 μm. Further, the digestion agent comprises the following material components: potassium persulfate, concentrated sulfuric acid and ultrapure water. The mass ratio of the potassium persulfate, the concentrated sulfuric acid and the ultrapure water is 1:0.94-1.14:19.44.

[0014] Further, the preparation of the digestion agent comprises the following steps: filtering ultrapure water (here, the first addition of ultrapure water, and the first addition of ultrapure water accounts for 82% of the total amount of ultrapure water) using a mixed cellulose ester filter membrane, adding the filtered ultrapure water into a reaction kettle for magnetic stirring at a rotating speed of 150 rpm and a temperature of 20-25℃ for 1 minute, adding potassium persulfate into the reaction kettle in three equal portions while stirring at a rotating speed of 150 rpm with an interval of 3 minutes, stirring for 3 minutes after adding all the potassium persulfate, adding concentrated sulfuric acid while stirring at a rotating speed of 200 rpm and controlling the temperature at ≤40℃ for 5 minutes, naturally cooling the temperature to 20-25℃, adding the remaining ultrapure water while stirring (here, the second addition of ultrapure water) at a rotating speed of 150-200 rpm for 10 minutes to prepare the digestion agent.

[0015] The pore size of the mixed cellulose ester filter membrane is 0.22 μm.

[0016] The present application has the following beneficial effects: 1. In the present application, the prepared color developing reagent is synergistically protected by the addition of polyethylene glycol diglycidyl ether, anhydrous ytterbium triflate and the treatment solution: the treatment solution is first deoxygenated by nitrogen, resistant to oxygen by sodium bisulfite and chelated metal ions by disodium ethylenediaminetetraacetate, clearing the interference, and also precisely adjusting the pH to 3.6±0.1, adapting to the catalytic and ester exchange requirements; anhydrous ytterbium triflate activates the epoxy groups of polyethylene glycol diglycidyl ether, shortening the reaction time; the pH stabilizing function of the treatment solution continues to play a role during this period, buffering the pH fluctuation caused by the reaction heat in real time, preventing the ring-opening failure of polyethylene glycol diglycidyl ether due to pH deviation, and also preventing the hydrolysis of molybdate; finally, the three synergistically make the color developing reagent have a long storage period at 4℃, and after mixing with the reducing reagent, it can quickly and uniformly release molybdate, with low absorbance deviation of phosphomolybdate blue color development.

[0017] 2. In the present application, the prepared reducing reagent provides a basic stable pH 3.0 environment for other materials to act by the pH stabilizing function of the phosphate buffer solution, which not only ensures the reducing activity of thiourea dioxide, but also guarantees the chelating ability of disodium ethylenediaminetetraacetate and L-cysteine, disodium ethylenediaminetetraacetate preferentially chelates high-concentration metal ions, and L-cysteine complements the complexation of trace residual ions, while consuming oxygen, the two synergistically eliminate the dual interference of metal ions and oxygen on the reducing system, the synergistic effect between thiourea dioxide and L-cysteine materials, L-cysteine does not affect the directional reduction ability of thiourea dioxide, and the reduction product of thiourea dioxide also does not interfere with the complexing function of L-cysteine, finally making the reducing reagent have high-efficiency reduction, strong anti-interference and long-term stable preservation.

[0018] 3. In the present application, the prepared color developing reagent first dissociates high-purity molybdate by adding ammonium molybdate tetrahydrate as the core active component of the reaction; polyethylene glycol diglycidyl ether, with its narrow distribution molecular chain and two end epoxy groups, reacts precisely with molybdate to form a structure-uniform molybdate ester, which not only avoids the high crosslinking unstable product caused by wide distribution ethers, but also protects the ester bond through the steric hindrance of the linear main chain to prevent molybdate from premature polymerization or hydrolysis, improving the storage stability; this molybdate ester structure has controllable dissociation characteristics during detection, and after subsequent mixing with the reducing reagent, it can quickly release molybdate to react with inorganic phosphorus to generate phosphomolybdate blue, achieving a balance between storage stability and reaction activity, and guaranteeing the accuracy and repeatability of total phosphorus detection. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of the present application.

[0020] It should be noted that the raw materials used in the following experiments are all commercially available.

[0021] Example 1, a water quality total phosphorus rapid detection reagent, the water quality total phosphorus rapid detection reagent comprising: a digestion agent, a color developing reagent and a reducing reagent; The color developing reagent comprises the following components: ammonium molybdate tetrahydrate, polyethylene glycol diglycidyl ether, ytterbium triflate anhydrous, a treatment solution and ultrapure water; The mass ratio of the ammonium molybdate tetrahydrate, polyethylene glycol diglycidyl ether, treatment solution, ultrapure water and ytterbium triflate anhydrous is 19:9:676:166:1.

[0022] The preparation of the treatment solution comprises the following steps: adding ultrapure water into a reaction kettle, passing in nitrogen for 20 minutes at a flow rate of 50 mL / min, adding dilute sulfuric acid, adjusting the pH value to 3.6, adding ethylenediaminetetraacetic acid disodium and sodium bisulfite, magnetic stirring at a speed of 300 rpm, and stirring for 2 minutes to obtain the treatment solution.

[0023] The mass ratio of the ultrapure water, ethylenediaminetetraacetic acid disodium and sodium bisulfite is 8000:2.4:1.

[0024] The reducing reagent comprises the following components: thiourea dioxide, L-cysteine, dehydroascorbic acid, phosphate buffer, ethylenediaminetetraacetic acid disodium and ultrapure water; The mass ratio of the thiourea dioxide, L-cysteine, dehydroascorbic acid, phosphate buffer, ultrapure water and ethylenediaminetetraacetic acid disodium is 10.9:36:17:27.8:9971:1.

[0025] The preparation of the phosphate buffer comprises the following steps: adding potassium dihydrogen phosphate and dipotassium hydrogen phosphate into a reaction kettle, adding ultrapure water and stirring at a speed of 100-160 rpm, adding a pH value adjusting solution dropwise, adjusting the pH value to 8, and obtaining the phosphate buffer.

[0026] The mass ratio of the potassium dihydrogen phosphate and dipotassium hydrogen phosphate is 1:5.18. The pH value adjusting solution is one of 1 mol / L sodium hydroxide solution and 1 mol / L hydrochloric acid solution.

[0027] The preparation of the color developing reagent includes the following steps: ammonium molybdate tetrahydrate is added into the treatment liquid in three equal parts with stirring, the stirring speed is 200-250 rpm, the interval is 5 minutes, after the third addition of ammonium molybdate tetrahydrate, the stirring speed is increased to 300 rpm, polyethylene glycol diglycidyl ether is added dropwise with stirring, the stirring speed is 300 rpm, the dropwise adding rate is 1 drop / s, after the completion of the dropwise adding of polyethylene glycol diglycidyl ether, ytterbium triflate is added with stirring, the stirring speed is 300 rpm, the temperature is controlled at ≤28℃, the pH value is controlled at 3.6, stirring is performed for 2.5 hours, ultrapure water is added with stirring, the stirring speed is 150-200 rpm, stirring is performed for 10 minutes, a reaction liquid is prepared, the reaction liquid is filtered using a mixed cellulose ester filter membrane, precipitates are filtered out, and the color developing reagent is prepared.

[0028] The preparation of the reducing reagent includes the following steps: phosphate buffer solution is added into a reaction kettle, nitrogen is introduced for 15 minutes at a flow rate of 50 mL / min, disodium ethylenediaminetetraacetate is added with stirring at a stirring speed of 200 rpm, stirring is performed for 3 minutes, a pretreatment liquid is prepared, dehydroascorbic acid is added with stirring at a stirring speed of 150-200 rpm, stirring is performed for 5-8 minutes, thiourea dioxide is added into the reaction kettle in two equal parts with stirring at a stirring speed of 180 rpm, the interval is 8 minutes, after the addition of all the thiourea dioxide into the reaction kettle, stirring is performed for 12 minutes, L-cysteine is added with stirring at a stirring speed of 200 rpm, stirring is performed for 5 minutes, hydrochloric acid is added dropwise with stirring, the pH value is adjusted to 3, the stirring speed is 150-200 rpm, stirring is performed for 5-10 minutes, ultrapure water is added with stirring at a stirring speed of 150-200 rpm, stirring is performed for 10 minutes, a reducing reagent is prepared by filtering out precipitates using a mixed cellulose ester filter membrane.

[0029] The digestion agent includes the following material components: potassium persulfate, concentrated sulfuric acid and ultrapure water. The mass ratio of the potassium persulfate, the concentrated sulfuric acid and the ultrapure water is 1:0.94:19.44.

[0030] The preparation of the digestion agent includes the following steps: ultrapure water is filtered using a mixed cellulose ester filter membrane, the filtered ultrapure water is added into a reaction kettle for magnetic stirring at a stirring speed of 150 rpm, the temperature is controlled at 20-25℃, stirring is performed for 1 minute, potassium persulfate is added into the reaction kettle in three equal parts with stirring at a stirring speed of 150 rpm, the interval is 3 minutes, after the addition of all the potassium persulfate, stirring is performed for 3 minutes, concentrated sulfuric acid is added with stirring at a stirring speed of 200 rpm, the temperature is controlled at ≤40℃, stirring is performed for 5 minutes, the temperature is naturally cooled to 20-25℃, the remaining ultrapure water is added with stirring at a stirring speed of 150-200 rpm, stirring is performed for 10 minutes, and a digestion agent is prepared.

[0031] Example 2, a water quality total phosphorus rapid detection reagent, the water quality total phosphorus rapid detection reagent includes: a digestion agent, a color developing reagent and a reducing reagent. The colorimetric reagent comprises the following components: ammonium molybdate tetrahydrate, polyethylene glycol diglycidyl ether, anhydrous ytterbium trifluoromethanesulfonate, treatment solution, and ultrapure water; The mass ratio of ammonium molybdate tetrahydrate, polyethylene glycol diglycidyl ether, treatment solution, ultrapure water, and anhydrous ytterbium trifluoromethanesulfonate is 20:10:676:167:1.

[0032] The preparation of the treatment solution includes the following steps: adding ultrapure water into the reaction vessel, purging nitrogen gas for 20 minutes at a flow rate of 50 mL / min, adding dilute sulfuric acid, adjusting the pH value to 3.6, adding disodium ethylenediaminetetraacetate and sodium bisulfite, and stirring magnetically at 300 rpm for 2 minutes to obtain the treatment solution.

[0033] The mass ratio of ultrapure water, disodium ethylenediaminetetraacetate, and sodium bisulfite is 8000:2.4:1.

[0034] The reducing reagent consists of the following components: thiourea dioxide, L-cysteine, dehydroascorbic acid, phosphate buffer, disodium ethylenediaminetetraacetate, and ultrapure water; The mass ratio of thiourea dioxide, L-cysteine, dehydroascorbic acid, phosphate buffer, ultrapure water, and disodium ethylenediaminetetraacetate is 11.9:36.3:17.4:28.8:9971:1.

[0035] The preparation of phosphate buffer includes the following steps: adding potassium dihydrogen phosphate and dipotassium hydrogen phosphate into a reaction vessel, adding ultrapure water and stirring at 100-160 rpm for 5 minutes, adding pH adjustment solution dropwise to adjust the pH to 8, and thus obtaining phosphate buffer.

[0036] The mass ratio of potassium dihydrogen phosphate to dipotassium hydrogen phosphate is 1:5.18; The pH adjusting solution is either a 1 mol / L sodium hydroxide solution or a 1 mol / L hydrochloric acid solution.

[0037] The preparation of the colorimetric reagent includes the following steps: Ammonium molybdate tetrahydrate is added to the treatment solution in three equal portions and stirred at 200-250 rpm with a 5-minute interval. After the third addition of ammonium molybdate tetrahydrate, the stirring speed is increased to 300 rpm. Polyethylene glycol diglycidyl ether is added dropwise and stirred at 300 rpm with a dropping rate of 1 drop / second. After the addition of polyethylene glycol diglycidyl ether is complete, anhydrous ytterbium trifluoromethanesulfonate is added and stirred at 300 rpm. The temperature is controlled at ≤28℃ and the pH value is controlled at 3.6. The mixture is stirred for 2.5 hours. Ultrapure water is then added and stirred at 150-200 rpm for 10 minutes to obtain the reaction solution. The reaction solution is filtered using a mixed cellulose ester filter membrane to remove the precipitate, thus obtaining the colorimetric reagent.

[0038] The preparation of the reducing reagent includes the following steps: phosphate buffer is added to a reaction vessel, nitrogen gas is introduced for 15 minutes at a flow rate of 50 mL / min, disodium ethylenediaminetetraacetate is added and stirred at 200 rpm for 3 minutes to obtain a pretreatment solution, dehydroascorbic acid is added and stirred at 150-200 rpm for 5-8 minutes, thiourea dioxide is added to the reaction vessel in two equal portions and stirred at 180 rpm with an 8-minute interval, until all thiourea dioxide is added to the reaction vessel, and stirred for 12 minutes, L-cysteine ​​is added and stirred at 200 rpm for 5 minutes, hydrochloric acid is added dropwise and stirred to adjust the pH to 3, and stirred at 150-200 rpm for 5-10 minutes, ultrapure water is added and stirred at 150-200 rpm for 10 minutes, and the precipitate is filtered out using a mixed cellulose ester filter membrane to obtain the reducing reagent.

[0039] The digestion agent consists of the following components: potassium persulfate, concentrated sulfuric acid, and ultrapure water; The mass ratio of potassium persulfate, concentrated sulfuric acid, and ultrapure water is 1:1.04:19.44.

[0040] The preparation of the digester includes the following steps: filtration of ultrapure water using a mixed cellulose ester filter membrane; addition of the filtered ultrapure water to a reaction vessel with magnetic stirring at 150 rpm and a temperature controlled at 20-25°C for 1 minute; addition of potassium persulfate in three equal portions to the reaction vessel with stirring at 150 rpm and 3-minute intervals; after all potassium persulfate has been added, stirring for 3 minutes; addition of concentrated sulfuric acid with stirring at 200 rpm and a temperature controlled at ≤40°C for 5 minutes; natural cooling to 20-25°C; addition of the remaining ultrapure water with stirring at 150-200 rpm for 10 minutes to obtain the digester.

[0041] Example 3: A rapid test reagent for total phosphorus in water quality, comprising: a digester, a colorimetric reagent, and a reducing reagent; The colorimetric reagent comprises the following components: ammonium molybdate tetrahydrate, polyethylene glycol diglycidyl ether, anhydrous ytterbium trifluoromethanesulfonate, treatment solution, and ultrapure water; The mass ratio of ammonium molybdate tetrahydrate, polyethylene glycol diglycidyl ether, treatment solution, ultrapure water, and anhydrous ytterbium trifluoromethanesulfonate is 21:11:676:168:1.

[0042] The preparation of the treatment solution includes the following steps: adding ultrapure water into the reaction vessel, purging nitrogen gas for 20 minutes at a flow rate of 50 mL / min, adding dilute sulfuric acid, adjusting the pH value to 3.6, adding disodium ethylenediaminetetraacetate and sodium bisulfite, and stirring magnetically at 300 rpm for 2 minutes to obtain the treatment solution.

[0043] The mass ratio of ultrapure water, disodium ethylenediaminetetraacetate, and sodium bisulfite is 8000:2.4:1.

[0044] The reducing reagent consists of the following components: thiourea dioxide, L-cysteine, dehydroascorbic acid, phosphate buffer, disodium ethylenediaminetetraacetate, and ultrapure water; The mass ratio of thiourea dioxide, L-cysteine, dehydroascorbic acid, phosphate buffer, ultrapure water, and disodium ethylenediaminetetraacetate is 12.9:36.6:17.8:29.8:9971:1.

[0045] The preparation of phosphate buffer includes the following steps: adding potassium dihydrogen phosphate and dipotassium hydrogen phosphate into a reaction vessel, adding ultrapure water and stirring at 100-160 rpm for 5 minutes, adding pH adjustment solution dropwise to adjust the pH to 8, and thus obtaining phosphate buffer.

[0046] The mass ratio of potassium dihydrogen phosphate to dipotassium hydrogen phosphate is 1:5.18; The pH adjusting solution is either a 1 mol / L sodium hydroxide solution or a 1 mol / L hydrochloric acid solution.

[0047] The preparation of the colorimetric reagent includes the following steps: Ammonium molybdate tetrahydrate is added to the treatment solution in three equal portions and stirred at 200-250 rpm with a 5-minute interval. After the third addition of ammonium molybdate tetrahydrate, the stirring speed is increased to 300 rpm. Polyethylene glycol diglycidyl ether is added dropwise and stirred at 300 rpm with a dropping rate of 1 drop / second. After the addition of polyethylene glycol diglycidyl ether is complete, anhydrous ytterbium trifluoromethanesulfonate is added and stirred at 300 rpm. The temperature is controlled at ≤28℃ and the pH value is controlled at 3.6. The mixture is stirred for 2.5 hours. Ultrapure water is then added and stirred at 150-200 rpm for 10 minutes to obtain the reaction solution. The reaction solution is filtered using a mixed cellulose ester filter membrane to remove the precipitate, thus obtaining the colorimetric reagent.

[0048] The preparation of the reducing reagent includes the following steps: phosphate buffer is added to a reaction vessel, nitrogen gas is introduced for 15 minutes at a flow rate of 50 mL / min, disodium ethylenediaminetetraacetate is added and stirred at 200 rpm for 3 minutes to obtain a pretreatment solution, dehydroascorbic acid is added and stirred at 150-200 rpm for 5-8 minutes, thiourea dioxide is added to the reaction vessel in two equal portions and stirred at 180 rpm with an 8-minute interval, until all thiourea dioxide is added to the reaction vessel, and stirred for 12 minutes, L-cysteine ​​is added and stirred at 200 rpm for 5 minutes, hydrochloric acid is added dropwise and stirred to adjust the pH to 3, and stirred at 150-200 rpm for 5-10 minutes, ultrapure water is added and stirred at 150-200 rpm for 10 minutes, and the precipitate is filtered out using a mixed cellulose ester filter membrane to obtain the reducing reagent.

[0049] The digestion agent consists of the following components: potassium persulfate, concentrated sulfuric acid, and ultrapure water; The mass ratio of potassium persulfate, concentrated sulfuric acid, and ultrapure water is 1:1.14:19.44.

[0050] The preparation of the digester includes the following steps: filtration of ultrapure water using a mixed cellulose ester filter membrane; addition of the filtered ultrapure water to a reaction vessel with magnetic stirring at 150 rpm and a temperature controlled at 20-25°C for 1 minute; addition of potassium persulfate in three equal portions to the reaction vessel with stirring at 150 rpm and 3-minute intervals; after all potassium persulfate has been added, stirring for 3 minutes; addition of concentrated sulfuric acid with stirring at 200 rpm and a temperature controlled at ≤40°C for 5 minutes; natural cooling to 20-25°C; addition of the remaining ultrapure water with stirring at 150-200 rpm for 10 minutes to obtain the digester.

[0051] Comparative Example 1: The difference between this comparative example and Example 1 is that: In this comparative example, no treatment solution was used as the colorimetric reagent.

[0052] Comparative Example 2: The difference between this comparative example and Example 1 is that: The colorimetric reagent used in this comparative example does not contain anhydrous ytterbium trifluoromethanesulfonate.

[0053] Comparative Example 3 differs from Example 1 in that: The colorimetric reagent in this comparative example does not contain polyethylene glycol diglycidyl ether.

[0054] Performance testing: The test reagents prepared in Examples 1, 2, 3, Comparative Examples 1, 2, and 3 were tested.

[0055] Performance testing: The relevant performance of the rapid total phosphorus detection reagent and its preparation method provided in Examples 1-3 and Comparative Examples 1-3 were tested respectively, and the test data are recorded in the table below:

[0056] The accuracy rates of the colorimetric reagents for the rapid detection reagents prepared in Examples 1, 2, 3, Comparative Examples 1, 2, and 3 were 98.6%, 98.9%, 98.3%, 88.6%, 94.2%, and 93.1%, respectively. The reaction times of the colorimetric reagents for the rapid detection reagents prepared in Examples 1, 2, 3, Comparative Examples 1, 2, and 3 were 2.7 h, 2.5 h, 2.8 h, 3.2 h, 3.1 h, and 4.2 h, respectively. The storage times of the colorimetric reagents for the rapid detection reagents prepared in Examples 1, 2, 3, Comparative Examples 1, 2, and 3 in brown bottles at 4°C were 40 days, 43 days, 41 days, 22 days, 24 days, and 15 days, respectively. It is evident that the rapid detection reagent prepared by this invention not only has high accuracy but also short detection time and long storage time. This indicates that the rapid detection reagent for total phosphorus in water and its preparation method provided by this invention have a broader market prospect and are more suitable for widespread application.

[0057] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0058] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A rapid test reagent for total phosphorus in water, characterized in that, The rapid test reagent for total phosphorus in water includes: a digester, a colorimetric reagent, and a reducing reagent; The colorimetric reagent comprises the following components: ammonium molybdate tetrahydrate, polyethylene glycol diglycidyl ether, anhydrous ytterbium trifluoromethanesulfonate, treatment solution, and ultrapure water; The mass ratio of ammonium molybdate tetrahydrate, polyethylene glycol diglycidyl ether, treatment solution, ultrapure water, and anhydrous ytterbium trifluoromethanesulfonate is 19-21:9-11:676:166-168:

1.

2. The rapid test reagent for total phosphorus in water according to claim 1, characterized in that, The preparation of the treatment solution includes the following steps: adding ultrapure water into the reaction vessel, purging nitrogen gas for 20 minutes, adding dilute sulfuric acid, adjusting the pH value to 3.6, adding disodium ethylenediaminetetraacetate and sodium bisulfite, and stirring magnetically for 2 minutes to obtain the treatment solution.

3. The rapid test reagent for total phosphorus in water according to claim 2, characterized in that, The mass ratio of ultrapure water, disodium ethylenediaminetetraacetate, and sodium bisulfite is 8000:2.4:

1.

4. The rapid test reagent for total phosphorus in water according to claim 1, characterized in that, The reducing agent comprises the following components: thiourea dioxide, L-cysteine, dehydroascorbic acid, phosphate buffer, disodium ethylenediaminetetraacetate, and ultrapure water; The mass ratio of thiourea dioxide, L-cysteine, dehydroascorbic acid, phosphate buffer, ultrapure water, and disodium EDTA is 10.9-12.9:36-36.6:17-17.8:27.8-29.8:9971:

1.

5. The rapid test reagent for total phosphorus in water according to claim 4, characterized in that, The preparation of the phosphate buffer includes the following steps: Potassium dihydrogen phosphate and dipotassium hydrogen phosphate were added to a reaction vessel, ultrapure water was added and stirred at 100-160 rpm for 5 minutes. pH adjustment solution was added dropwise to adjust the pH to 8, thus preparing a phosphate buffer solution.

6. The rapid test reagent for total phosphorus in water according to claim 5, characterized in that, The mass ratio of potassium dihydrogen phosphate to dipotassium hydrogen phosphate is 1:5.18; The pH adjusting solution is either a 1 mol / L sodium hydroxide solution or a 1 mol / L hydrochloric acid solution.

7. The preparation method of the rapid test reagent for total phosphorus in water according to claim 1, characterized in that, The preparation of the colorimetric reagent includes the following steps: Ammonium molybdate tetrahydrate was added to the treatment solution in three equal portions, with stirring at 200-250 rpm and 5-minute intervals. After the third addition of ammonium molybdate tetrahydrate, the stirring speed was increased to 300 rpm. Polyethylene glycol diglycidyl ether was then added dropwise with stirring at 300 rpm at a dropping rate of 1 drop / second. After the addition of polyethylene glycol diglycidyl ether was complete, anhydrous ytterbium trifluoromethanesulfonate was added with stirring at 300 rpm. The temperature was controlled at ≤28℃ and the pH value was controlled at 3.

6. The mixture was stirred for 2.5 hours. Then, ultrapure water was added and stirred at 150-200 rpm for 10 minutes to obtain the reaction solution. The reaction solution was filtered using a mixed cellulose ester filter membrane to remove the precipitate, thus obtaining the colorimetric reagent.

8. The preparation method of the rapid test reagent for total phosphorus in water according to claim 1, characterized in that, The preparation of the reducing agent includes the following steps: Phosphate buffer was added to the reaction vessel, nitrogen gas was introduced for 15 minutes at a flow rate of 50 mL / min, disodium EDTA was added and stirred at 200 rpm for 3 minutes to obtain the pretreatment solution. Dehydroascorbic acid was added and stirred at 150-200 rpm for 5-8 minutes. Thiourea dioxide was added to the reaction vessel in two equal portions and stirred at 180 rpm with an 8-minute interval. After all the thiourea dioxide was added to the reaction vessel, it was stirred for 12 minutes. L-cysteine ​​was added and stirred at 200 rpm for 5 minutes. Hydrochloric acid was added dropwise and stirred to adjust the pH to 3. The pH was stirred at 150-200 rpm for 5-10 minutes. Ultrapure water was added and stirred at 150-200 rpm for 10 minutes. The precipitate was filtered out using a mixed cellulose ester filter membrane to obtain the reducing reagent.

9. The rapid test reagent for total phosphorus in water according to claim 1, characterized in that, The digesting agent comprises the following components: potassium persulfate, concentrated sulfuric acid, and ultrapure water; The mass ratio of potassium persulfate, concentrated sulfuric acid, and ultrapure water is 1:0.94-1.14:19.

44.

10. The preparation method of the rapid detection reagent for total phosphorus in water according to claim 1, characterized in that, The preparation of the digestion agent includes the following steps: ultrapure water is filtered using a mixed cellulose ester filter membrane. The filtered ultrapure water is added to a reaction vessel and magnetically stirred. The temperature is controlled at 20-25℃ and stirred for 1 minute. Potassium persulfate is added to the reaction vessel in three equal portions and stirred at 3-minute intervals. After all the potassium persulfate has been added, the mixture is stirred for 3 minutes. Concentrated sulfuric acid is added and stirred. The temperature is controlled at ≤40℃ and stirred for 5 minutes. The temperature is allowed to cool naturally to 20-25℃. The remaining ultrapure water is added and stirred at 150-200 rpm for 10 minutes to obtain the digestion agent.

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