CN111238991A - Method for measuring hypophosphorous acid - Google Patents
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- CN111238991A CN111238991A CN202010105360.3A CN202010105360A CN111238991A CN 111238991 A CN111238991 A CN 111238991A CN 202010105360 A CN202010105360 A CN 202010105360A CN 111238991 A CN111238991 A CN 111238991A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N5/00—Analysing materials by weighing, e.g. weighing small particles separated from a gas or liquid
- G01N5/04—Analysing materials by weighing, e.g. weighing small particles separated from a gas or liquid by removing a component, e.g. by evaporation, and weighing the remainder
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N1/00—Sampling; Preparing specimens for investigation
- G01N1/28—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q
- G01N1/38—Diluting, dispersing or mixing samples
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N1/00—Sampling; Preparing specimens for investigation
- G01N1/28—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q
- G01N1/44—Sample treatment involving radiation, e.g. heat
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Abstract
The invention discloses a method for measuring hypophosphorous acid, which comprises the steps of firstly oxidizing hypophosphorous acid and phosphorous acid into orthophosphoric acid by taking ammonium ceric nitrate as an oxidizing agent, and then measuring the content of phosphorus by a gravimetric method, thereby realizing the measurement of the hypophosphorous acid. The invention can realize the determination of the hypophosphorous acid, has high measurement accuracy and wide applicable range and can be widely applied.
Description
Technical Field
The invention relates to a method for measuring phosphorus, in particular to a method for measuring hypophosphorous acid.
Background
The application of phosphorus in production and life is very wide, and the phosphorus plays an extremely important role in national economy. The phosphorus content is used as a conventional determination project in the phosphorus chemical industry, and the method is divided into a chemical analysis method and an instrument analysis method. Among them, the most common laboratory in the instrumental analysis methods is the spectrophotometry, which is divided into phosphovanadium molybdenum yellow method, phosphomolybdenum blue method and ion association method, and in the high-end analysis field, the instrumental analysis methods also include ion chromatography and ICP-AES method; the chemical analysis method mainly comprises a quinmolybdic citraconic ketone gravimetric method and a volumetric method, and the two methods are commonly used in laboratories for measuring the phosphorus content. Among them, the gravimetric method is considered to be an arbitration method because of its extremely high accuracy and wide measurement range (about 30-130 mg/L).
Hypophosphorous acid and salts thereof are novel fine phosphorus chemical products which are concerned in recent years, but the production technology of the hypophosphorous acid is complex and difficult, and particularly, the research and the technical promotion of the hypophosphorous acid are restricted due to the lack of detection means of the hypophosphorous acid. The hypophosphorous acid is still measured by adopting an oxidation-reduction titration method at present, but the method is lack of research on selection of an oxidant, an indicator, oxidation conditions and the like, and the conventional method has the problem of large measurement error caused by insensitive titration end point.
The principle of the method is that orthophosphate and molybdate react quantitatively under acidic condition to form phosphomolybdic heteropoly acid, and the phosphorus content is calculated by measuring the content of the phosphomolybdic heteropoly acid. Therefore, for the determination of other forms of phosphoric acid and salts (such as hypophosphorous acid and salts, condensed phosphoric acid and salts, organic phosphorus and the like), pretreatment such as digestion is often adopted, and other forms of phosphorus compounds must be completely converted into orthophosphoric acid to determine the phosphorus content, namely the total phosphorus content. Common digestion methods are: potassium persulfate decomposition, nitric acid-sulfuric acid decomposition, nitric acid-perchloric acid decomposition. However, the digestion treatment is often suitable for measuring the content of trace phosphorus by an extensive method and the like, and only a result of the content of total phosphorus can be obtained.
However, there is little research on pretreatment of samples in the weight method of the quinomolybdemum citranone, and particularly, no report is found on the method for measuring hypophosphorous acid and salts by the weight method of the quinomolybdemum citranone.
The gravimetric method for measuring the phosphorus content is a relatively mature measuring method, and the method has the advantages of high measuring accuracy and small deviation. However, the gravimetric method is only suitable for the determination of orthophosphoric acid radicals, and is not suitable for hypophosphorous acid at all. Therefore, the determination of hypophosphorous acid, that is, the determination of hypophosphorous acid, phosphorous acid and hypophosphite, cannot be directly performed by a gravimetric method, or when the content of a sample containing mixed phosphorous acid and hypophosphorous acid is measured, the conventional method cannot be completed by a gravimetric method.
Disclosure of Invention
The present invention aims to provide a method for measuring hypophosphorous acid. The invention can realize the determination of the hypophosphorous acid, has high measurement accuracy and wide applicable range and can be widely applied.
The technical scheme of the invention is as follows: the method for determining hypophosphorous acid comprises the steps of firstly using ammonium ceric nitrate as an oxidizing agent to oxidize hypophosphorous acid and phosphorous acid into orthophosphoric acid, and then determining the content of phosphorus by a gravimetric method, thereby realizing the determination of the hypophosphorous acid.
The method for measuring the hypophosphorous acid comprises the following specific steps:
1) and (3) oxidation: dissolving hypophosphorous acid in water to obtain a solution to be detected; adding concentrated nitric acid and ammonium ceric nitrate into the solution to be detected, stirring uniformly, heating to boil, keeping the hypophosphorous acid in the solution completely oxidized, and decomposing the excessive ammonium ceric nitrate;
2) and (3) precipitation: adding concentrated nitric acid into the solution to be detected oxidized in the step 1), adding a quinomolybdenyl citranone reagent, heating the solution in a water bath, taking out the solution, cooling the solution to room temperature, performing suction filtration, heating and drying the precipitate to constant weight, cooling the precipitate to room temperature, weighing the precipitate, and finally calculating the content of hypophosphorous acid according to the weighed weight.
In the method for measuring hypophosphorous acid, in step 1), the solid-to-liquid ratio of hypophosphorous acid, concentrated nitric acid and cerium ammonium nitrate is 1: 400-600: 700-800.
In the method for measuring hypophosphorous acid, the solid-to-liquid ratio of the hypophosphorous acid, the concentrated nitric acid and the cerium ammonium nitrate is 1: 500: 750.
in the method for measuring hypophosphorous acid, the boiling time after heating in step 1) is more than 15 min.
In the method for measuring hypophosphorous acid, when concentrated nitric acid and quinomolybdyl citranone are added in step 2), the mass-to-volume ratio of hypophosphorous acid to concentrated nitric acid to quinomolybdyl citranone is 1: 200-300: 2000-3000.
In the method for measuring hypophosphorous acid, the mass-to-volume ratio of the hypophosphorous acid, the concentrated nitric acid and the quinomolybdic citranone is 1: 250: 2500.
in the method for measuring the hypophosphorous acid, the water bath heating temperature in the step 2) is 75 ℃, the water bath heating time is 5-10min, and the hypophosphorous acid is naturally cooled after the water bath heating.
In the method for measuring the hypophosphorous acid, the drying in the step 2) is carried out at the temperature of 245-.
In the method for measuring the hypophosphorous acid, after the drying in the step 2), the mixture is placed in a dryer to be cooled for 20-30 min.
The invention has the advantages of
According to the invention, a proper oxidant and an oxidation process are obtained through research, after hypophosphorous acid is completely oxidized into orthophosphoric acid, the phosphorus content is measured by a traditional gravimetric method, so that the gravimetric method measurement of the hypophosphorous acid is realized; in the measuring process, the method has the advantages of high measuring accuracy and wide measuring range, and can be widely popularized and applied.
Firstly, the determination principle of the invention is as follows:
before using the precipitator, namely the quinomolybdenyl citranone, the phosphorous acid and the hypophosphorous acid are completely oxidized into orthophosphoric acid by using an oxidizing agent, so that the aim of accurately measuring the phosphorus content is fulfilled. The chemical reactions that take place are as follows:
and (3) oxidation: ce4++PO3 3-+H2O＝2Ce3++PO4 3-+2H+
3Ce4++PO2 3-+2H2O＝3Ce3++PO4 3-+4H+
II, measurement steps of actual experiments:
and (3) oxidation: taking 1.0000g (accurate to 0.0001g) of sample, placing the sample in a 100mL small beaker for dissolving, transferring the sample into a 500mL volumetric flask, diluting the sample to the scale with water, and shaking up to prepare the solution to be tested. Putting 10mL of solution to be detected in a 250mL beaker, adding pure water to 100mL, adding 10mL of concentrated nitric acid, and then adding 15mL of ammonium ceric nitrate solution. Putting a glass rod in a beaker, covering a watch glass, putting the beaker on an electric hot plate, heating the beaker to boil the solution for more than 15 minutes so as to fully oxidize all phosphorus-containing compounds in the solution and decompose excessive ammonium cerium nitrate.
And (3) precipitation: 5mL of concentrated nitric acid is added into the oxidized sample solution, and 50mL of the quinomolybdenyl citraconic reagent is added. The mixture is placed in a water bath kettle at the temperature of 75 ℃ for heating for a plurality of minutes, and the heating is stopped. The beaker was removed and cooled to room temperature. And (3) performing suction filtration by using a glass crucible with constant weight in advance, transferring the precipitate into the glass crucible, placing the glass crucible into a blowing drying oven at 250 ℃ (-5 ℃) to dry the precipitate to constant weight, then placing the dried precipitate into a dryer to cool the dried precipitate for 20-30 minutes to room temperature, and weighing the dried precipitate.
Thirdly, calculation of measurement results
ρ(P)＝(0.01400×"("m1-m2")")/(m×10/500)×100"％"
Wherein:
0.01400 coefficient for conversion of quinoline phosphomolybdate molar mass to phosphorus molar mass
m 1-crucible and pellet mass, g;
m 2-crucible mass, g;
m-sample weight, g
Fourth, specific measurement example
1. Determination of hypophosphorous acid
TABLE 1 hypophosphorous acid determination after oxidation with 0.1mol/L ammonium cerium nitrate
As can be seen from Table 1, the comparison of the measurement results of adding cerium ammonium nitrate with those of adding no cerium ammonium nitrate is clear when determining the phosphorus content in hypophosphorous acid. The measurement result of adding 20mL of ammonium ceric nitrate is slightly higher than that of adding 40mL of ammonium ceric nitrate, but the effect of oxidizing hypophosphorous acid is very good and the measurement result is stable.
2. Determination of phosphorous acid
TABLE 2 phosphorous acid determination after oxidation with 0.1mol/L cerium ammonium nitrate
As can be seen from Table 2, compared with the case where no ammonium ceric nitrate is added, the ammonium ceric nitrate has a similar effect of oxidizing phosphorous acid as the effect of oxidizing hypophosphorous acid, and can achieve a better oxidation effect, so as to measure the phosphorus content more accurately.
3. Determination of Mixed phosphorus samples
Samples are prepared according to different proportions of orthophosphoric acid, phosphorous acid and hypophosphorous acid, 0.1mol/L ammonium ceric nitrate is added for oxidation and then the effect is measured, and the effect is shown in the following table.
TABLE 3 orthophosphoric acid 60% phosphorous acid 20% hypophosphorous acid 20%
TABLE 4 orthophosphoric acid 80% phosphorous acid 10% hypophosphorous acid 10%
As is clear from tables 3 and 4, the cerium ammonium nitrate showed excellent oxidation effect and stable results for the samples having different contents of orthophosphoric acid, phosphorous acid and hypophosphorous acid.
Detailed Description
The present invention is further illustrated by the following examples, which are not to be construed as limiting the invention.
Examples of the invention
Example 1: a method for measuring hypophosphorous acid comprises the following specific steps:
1) and (3) oxidation: dissolving hypophosphorous acid in water to obtain a solution to be detected; adding concentrated nitric acid and ammonium ceric nitrate into the solution to be detected, uniformly stirring, heating to boil for more than 15min, keeping hypophosphorous acid in the solution completely oxidized, and decomposing excessive ammonium ceric nitrate, wherein the solid-to-liquid ratio of hypophosphorous acid to concentrated nitric acid to ammonium ceric nitrate is 1: 500: 750;
2) and (3) precipitation: adding concentrated nitric acid into the solution to be detected oxidized in the step 1), and then adding a quinomolybdenyl citrazone reagent, wherein the mass-to-volume ratio of hypophosphorous acid to concentrated nitric acid to quinomolybdenyl citrazone is 1: 250: 2500, then placing the mixture in a 75 ℃ water bath kettle to heat for 8min, then taking out, naturally cooling to room temperature, carrying out suction filtration, heating and drying the precipitate at 250 ℃ by a blast drying oven to constant weight, then placing the precipitate in a dryer to cool for 25min to room temperature, weighing, and finally calculating the content of hypophosphorous acid according to the weighed weight.
Example 2: a method for measuring hypophosphorous acid comprises the following specific steps:
1) and (3) oxidation: dissolving hypophosphorous acid in water to obtain a solution to be detected; adding concentrated nitric acid and ammonium ceric nitrate into the solution to be detected, uniformly stirring, heating to boil for more than 15min, keeping hypophosphorous acid in the solution completely oxidized, and decomposing excessive ammonium ceric nitrate, wherein the solid-to-liquid ratio of hypophosphorous acid to concentrated nitric acid to ammonium ceric nitrate is 1: 400: 700 of the base material;
2) and (3) precipitation: adding concentrated nitric acid into the solution to be detected oxidized in the step 1), and then adding a quinomolybdenyl citrazone reagent, wherein the mass-to-volume ratio of hypophosphorous acid to concentrated nitric acid to quinomolybdenyl citrazone is 1: 200: 2000, then placing the precipitate in a 75 ℃ water bath to heat for 5min, then taking out, naturally cooling to room temperature, carrying out suction filtration, heating and drying the precipitate at 245 ℃ by a blast drying oven to constant weight, then placing the precipitate in a dryer to cool for 20min to room temperature, then weighing, and finally calculating the content of hypophosphorous acid according to the weighed weight.
Example 3: a method for measuring hypophosphorous acid comprises the following specific steps:
1) and (3) oxidation: dissolving hypophosphorous acid in water to obtain a solution to be detected; adding concentrated nitric acid and ammonium ceric nitrate into the solution to be detected, uniformly stirring, heating to boil for more than 15min, keeping hypophosphorous acid in the solution completely oxidized, and decomposing excessive ammonium ceric nitrate, wherein the solid-to-liquid ratio of hypophosphorous acid to concentrated nitric acid to ammonium ceric nitrate is 1: 600: 800;
2) and (3) precipitation: adding concentrated nitric acid into the solution to be detected oxidized in the step 1), and then adding a quinomolybdenyl citrazone reagent, wherein the mass-to-volume ratio of hypophosphorous acid to concentrated nitric acid to quinomolybdenyl citrazone is 1: 300: 3000, then placing the precipitate in a 75 ℃ water bath to heat for 10min, then taking out, naturally cooling to room temperature, carrying out suction filtration, heating and drying the precipitate at 255 ℃ by using a blast drying oven to constant weight, then placing the precipitate in a dryer to cool for 30min to room temperature, weighing, and finally calculating the content of hypophosphorous acid according to the weighed weight.
The above description is only for the purpose of illustrating the present invention and the appended claims, and the scope of the present invention is not limited thereto, and any person skilled in the art can substitute or change the technical solution and the inventive concept of the present invention within the technical scope of the present invention.
Claims (10)
1. A method for measuring hypophosphorous acid, which is characterized by comprising the following steps: firstly, cerium ammonium nitrate is used as an oxidant, hypophosphorous acid and phosphorous acid are oxidized into orthophosphoric acid, and then the content of phosphorus is determined by a gravimetric method, so that the determination of the hypophosphorous acid is realized.
2. The method for measuring hypophosphorous acid according to claim 1, comprising: the method comprises the following specific steps:
1) and (3) oxidation: dissolving hypophosphorous acid in water to obtain a solution to be detected; adding concentrated nitric acid and ammonium ceric nitrate into the solution to be detected, stirring uniformly, heating to boil, keeping the hypophosphorous acid in the solution completely oxidized, and decomposing the excessive ammonium ceric nitrate;
2) and (3) precipitation: adding concentrated nitric acid into the solution to be detected oxidized in the step 1), adding a quinomolybdenyl citranone reagent, heating the solution in a water bath, taking out the solution, cooling the solution to room temperature, performing suction filtration, heating and drying the precipitate to constant weight, cooling the precipitate to room temperature, weighing the precipitate, and finally calculating the content of hypophosphorous acid according to the weighed weight.
3. The method for measuring hypophosphorous acid according to claim 2, comprising: the solid-to-liquid ratio of the hypophosphorous acid, the concentrated nitric acid and the ammonium ceric nitrate in the step 1) is 1: 400-600: 700-800.
4. The method for measuring hypophosphorous acid according to claim 3, comprising: the solid-liquid ratio of the hypophosphorous acid to the concentrated nitric acid to the ammonium ceric nitrate is 1: 500: 750.
5. the method for measuring hypophosphorous acid according to claim 2, comprising: the boiling time after the heating in the step 1) is more than 15 min.
6. The method for measuring hypophosphorous acid according to claim 2, comprising: when the concentrated nitric acid and the quinomolybdenyl citracone are added in the step 2), the mass-to-volume ratio of the hypophosphorous acid to the concentrated nitric acid to the quinomolybdenyl citracone is 1: 200-300: 2000-3000.
7. The method for measuring hypophosphorous acid according to claim 6, comprising: the mass-volume ratio of the hypophosphorous acid to the concentrated nitric acid to the quinomolybdenyl citranone is 1: 250: 2500.
8. the method for measuring hypophosphorous acid according to claim 2, comprising: and 2) heating in a water bath at the temperature of 75 ℃, heating in the water bath for 5-10min, and naturally cooling after heating in the water bath.
9. The method for measuring hypophosphorous acid according to claim 2, comprising: step 2) the drying is carried out by an air-blast drying oven at the temperature of 245-255 ℃.
10. The method for measuring hypophosphorous acid according to claim 2, comprising: and 2) drying, and then placing in a dryer for cooling for 20-30 min.
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3816075A (en) * | 1972-11-28 | 1974-06-11 | Atomic Energy Commission | Determination of hypophosphite ion concentration |
| JP2001079570A (en) * | 1999-09-10 | 2001-03-27 | Sumitomo Metal Mining Co Ltd | Treatment process for electroless nickel plating waste solution |
| CN101413912A (en) * | 2008-11-06 | 2009-04-22 | 浙江工业大学 | Method for measuring phosphate radical concentration in chemical nickel plating solution |
| CN102141538A (en) * | 2010-12-06 | 2011-08-03 | 山东大学 | Method for determining concentration of phosphite by cyclic voltammetry |
-
2020
- 2020-02-20 CN CN202010105360.3A patent/CN111238991A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3816075A (en) * | 1972-11-28 | 1974-06-11 | Atomic Energy Commission | Determination of hypophosphite ion concentration |
| JP2001079570A (en) * | 1999-09-10 | 2001-03-27 | Sumitomo Metal Mining Co Ltd | Treatment process for electroless nickel plating waste solution |
| CN101413912A (en) * | 2008-11-06 | 2009-04-22 | 浙江工业大学 | Method for measuring phosphate radical concentration in chemical nickel plating solution |
| CN102141538A (en) * | 2010-12-06 | 2011-08-03 | 山东大学 | Method for determining concentration of phosphite by cyclic voltammetry |
Non-Patent Citations (5)
| Title |
|---|
| 刘方方等: "硝酸铈法测定次磷酸及亚磷酸的含量", 《山东化工》 * |
| 唐华应: "应用空气中氧自动氧化亚磷酸为正磷酸光度法测定金属试样中磷量", 《四川冶金》 * |
| 张道礼等: "化学镀镍溶液中次亚磷酸钠浓度测定方法的比较", 《材料保护》 * |
| 徐丽金: "胺共存时次亚磷酸根和亚磷酸根耗铈（Ⅳ）总量的测定", 《南昌大学学报(工程技术版)》 * |
| 阮代锬等: "含磷酸解液中磷含量测定方法的探究", 《磷肥与复肥》 * |
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