阅读说明：本技术 一种区分磷的不同价态含氧酸盐亚磷酸钠及次磷酸钠的方法 (Method for distinguishing different valence states of phosphorus, oxysalt sodium phosphite and sodium hypophosphite ) 是由 胡刚 周彦珂 陈卓 于 2020-10-10 设计创作，主要内容包括：一种区分磷的不同价态含氧酸盐亚磷酸钠及次磷酸钠的方法,其特征在于：应用“H-2SO-4-KIO-3-[NiL](ClO-4)-2-丙二酸-H-2O-2”化学振荡体系作为区分溶液,根据亚磷酸钠及次磷酸钠对该体系振荡的影响不同,从而实现亚磷酸钠及次磷酸钠的区分。本发明所涉及的区分方法所提供的电位振荡图谱具有直观性,可以方便快捷地区分出亚磷酸钠及次磷酸钠,而且设备简单、准确度高、易于操作和观察。(A method for distinguishing different valence states of oxysalt sodium phosphite and sodium hypophosphite of phosphorus is characterized in that: application of "H 2 SO 4 ‑KIO 3 ‑[NiL](ClO 4 ) 2 -malonic acid-H 2 O 2 The chemical oscillation system is used as a distinguishing solution, and the distinguishing of the sodium phosphite and the sodium hypophosphite is realized according to different influences of the sodium phosphite and the sodium hypophosphite on the oscillation of the system. The potential oscillation spectrum provided by the distinguishing method has intuition, can distinguish sodium phosphite and sodium hypophosphite conveniently and quickly, and has the advantages of simple equipment, high accuracy and easy operation and observation.)

1. A method for distinguishing different valence states of oxysalt sodium phosphite and sodium hypophosphite of phosphorus is characterized in that:

preparing a solution of a sample to be distinguished by using distilled water as a solvent;

application of "H₂SO₄ - KIO₃ - [NiL](ClO₄)₂ -malonic acid-H₂O₂The chemical oscillation system is used as a distinguishing solution, a potential oscillation spectrum of the potential of the chemical oscillation system along with the change of time is recorded, at any stable potential lowest point generated by oscillation, solutions of sodium phosphite or sodium hypophosphite to be distinguished samples are respectively added into the two groups of distinguishing solutions, and the distinguishing of the samples to be distinguished is realized according to different influences of the samples to be distinguished on the chemical oscillation system: if the chemical oscillation is inhibited after the solution to be distinguished is added, the oscillation is recovered along with a period of inhibition time, and meanwhile, the oscillation life is shortened due to the reduction of the chemical oscillation amplitude, the added sample to be distinguished is sodium phosphite; if the chemical oscillation amplitude is reduced after the solution to be distinguished is added, the oscillation life is shortened, but no inhibition time appears, the added sample to be distinguished is sodium hypophosphite;

[NiL](ClO₄)₂wherein L is 5, 7, 7, 12, 14, 14-hexamethyl-1, 4, 8, 11-tetraazacyclotetradec-4, 11-diene; the molar concentration of each component in the distinguishing solution is as follows: 0.0246468-0.025mol/L sulfuric acid, 0.0175-0.021mol/L potassium iodate, [ NiL](ClO₄)₂6.4875×10^-4-8.65×10^-4mol/L, 0.125-0.165mol/L of malonic acid and 1.35-1.45mol/L of hydrogen peroxide.

2. The discrimination method according to claim 1, characterized in that: the molar concentration of each component in the solution is 0.025mol/L sulfuric acid, 0.01855mol/L potassium iodate and [ NiL ]](ClO₄)₂ 8.65×10^-4mol/L, 0.135mol/L of malonic acid and 1.4mol/L of hydrogen peroxide.

3. The discrimination method according to claim 1, characterized in that: the stable potential lowest point generated by oscillation is any one of the 3 rd to 25 th potential lowest points generated by oscillation.

4. The discrimination method according to claim 1, characterized in that: the distinguishable concentration range of the sample to be distinguished in the distinguishing solution is 5.0X 10^-3-2.25×10^-2mol/L。

Technical Field

The invention relates to a distinguishing method, in particular to a tetraazacyclotetradecadiene nickel complex [ NiL ]](ClO₄)₂ A method for distinguishing different valence state oxysalt sodium phosphite and sodium hypophosphite of phosphorus by a catalytic chemical oscillation system, wherein a ligand L is 5, 7, 7, 12, 14, 14-hexamethyl-1, 4, 8, 11-tetraazacyclotetradecyl-4, 11-diene, belongs to the field of qualitative analytical chemistry.

Background

Sodium phosphite and sodium hypophosphite belong to salts of oxyacids corresponding to the same element, and play a very important role in each field. Sodium phosphite, molecular formula: na (Na)₂HPO₃Sodium phosphite can be used as a reducing agent to reduce metal salts such as gold, silver, mercury, nickel, chromium, cobalt and the like into corresponding metals. Can also be used as an antioxidant in textile finishing, medicine and other industries. Sodium hypophosphite, molecular formula: NaH₂PO₂Sodium hypophosphite can replace stainless steel materials and can be widely applied to the industries of electronics, machinery, petroleum, chemical engineering, aviation, navigation, food, medicine and the like. Can be made of plastics, ceramics, glass,And (3) metalizing the surface of non-metallic materials such as quartz and the like. It can also be used as catalyst and stabilizer for chemical reaction.

Methods that have been reported to distinguish between the two include physical methods and chemical methods: 1. the physical method comprises the following steps: sodium phosphite, mostly in the form of crystalline powder; sodium hypophosphite, mostly in the form of crystals. The method is only suitable for analyzing crystals and has large limitation. 2. The chemical method comprises the following steps: sodium phosphite, heating and stabilizing; sodium hypophosphite is explosive and unstable when heated. Although the method can realize the distinction between the two, the generation of the phosphine which is a highly toxic gas in the distinguishing process causes pollution to the environment. Therefore, it is necessary to find a qualitative analysis method with good distinguishing effect, simple and fast operation and easy judgment of result. Both of them are shown in structural formula (I)

The structure of sodium phosphite and sodium hypophosphite with the structural formula (I).

Disclosure of Invention

The invention aims to provide a novel, convenient and quick distinguishing method for sodium phosphite and sodium hypophosphite, namely application of [ NiL ]](ClO₄)₂The method for distinguishing sodium phosphite from sodium hypophosphite by a catalyzed chemical oscillation system is an electrochemical oscillation system method developed based on the acute response of the chemical oscillation system catalyzed by the complex to the sodium phosphite and the sodium hypophosphite. Specifically, samples (sodium phosphite and sodium hypophosphite) with the same concentration to be distinguished are respectively added into two groups of chemical oscillation systems, and the samples to be distinguished are distinguished according to different influences of the samples to be distinguished on the chemical oscillation systems: if the chemical oscillation is inhibited after the solution to be distinguished is added, the oscillation is recovered along with a period of inhibition time, and meanwhile, the oscillation life is shortened due to the reduction of the chemical oscillation amplitude, the added sample to be distinguished is sodium phosphite; if the chemical oscillation amplitude is reduced after the solution to be distinguished is added, the oscillation life is shortened, but no inhibition time appears, the added sample to be distinguished is sodium hypophosphite,the invention has short sample processing time, simple and easily controlled measuring conditions and convenient popularization and application.

The invention solves the technical problem and adopts the following technical scheme:

the invention provides a distinguishing method for sodium phosphite and sodium hypophosphite, which is characterized in that:

preparing a solution of a sample to be distinguished by using distilled water as a solvent;

application of "H₂SO₄ - KIO₃ - [NiL](ClO₄)₂ -malonic acid-H₂O₂The chemical oscillation system is used as a distinguishing solution, a potential oscillation spectrum of the chemical oscillation system is recorded, solutions of sodium phosphite and sodium hypophosphite to be distinguished samples are respectively added into two groups of distinguishing solutions (the chemical oscillation systems) at any stable potential lowest point, and qualitative analysis of the samples to be distinguished is realized according to different influences of the samples to be distinguished on the chemical oscillation system: if the chemical oscillation is inhibited after the solution to be distinguished is added, the oscillation is recovered along with a period of inhibition time, and meanwhile, the oscillation life is shortened due to the reduction of the chemical oscillation amplitude, the added sample to be distinguished is sodium phosphite; if the chemical oscillation amplitude is reduced after the solution to be distinguished is added, the oscillation life is shortened, but no inhibition time appears, and the added sample to be distinguished is sodium hypophosphite.

The stable potential lowest point generated by oscillation is any one of the 3 rd to 25 th potential lowest points generated by oscillation.

The tetraazacyclotetradecadiene nickel complex is [ NiL](ClO₄)₂Wherein ligand L is 5, 7, 7, 12, 14, 14-hexamethyl-1, 4, 8, 11-tetraazacyclotetradec-4, 11-diene. [ NiL ]](ClO₄)₂The structure is shown as formula (II)

Structural formula (II) [ NiL](ClO₄)₂The structure of (1).

The structure of the complex and myoglobin in a living bodyThe porphyrin rings of the key structures of proteins, haemoglobins, chlorophylls and some metalloenzymes are very similar and are defined by the formula [ NiL](ClO₄)₂The catalyzed chemical oscillatory reaction is similar to biochemical oscillations within plant and animal cells. Therefore, the system has stable amplitude, long oscillation life and sharp response to sodium phosphite and sodium hypophosphite.

[NiL](ClO₄)₂The preparation method comprises the following two steps: 1) preparation of L.2 HClO₄(ii) a 2) From L.2 HClO₄Preparation of [ NiL](ClO₄)₂。

1) Preparation of L.2 HClO₄：

98.5mL of ethylenediamine were placed in a 500mL three-necked flask and 126mL of 70% perchloric acid were slowly added dropwise with stirring over 120 minutes under ice-bath conditions. The initial reaction was vigorous with white smoke generation, so the dropping rate was controlled to be one drop per 5 seconds. The dropping speed can be increased appropriately as the reaction proceeds until the dropping is completed, and a transparent solution is obtained. Still under ice-water bath conditions, to the clear solution was added 224mL of anhydrous acetone and stirred vigorously, the solution quickly becoming cloudy and a very viscous mixture formed. Still under ice-water bath conditions for 2-3 hours for adequate reaction. And transferring the obtained product to a Buchner funnel for suction filtration and separation, and fully washing the product with acetone to obtain a pure white solid. Recrystallizing the self-color solid in hot methanol-water solution, and vacuum drying with silica gel desiccant to obtain 80g white crystal of L.2 HClO₄。

Reference documents:

1.Curtis, N. F. and Hay, R. W. , J. Chem. Soc. , Chem. Commun. , 1966, p. 534.

2.Gang Hu, Panpan Chen, Wei Wang, Lin Hu, Jimei Song, LingguangQiu, Juan Song, E1ectrochimica Acta, 2007, Vol. 52, pp. 7996-8002.

3. Lin Hu, Gang Hu, Han-Hong Xu, J. Ana1. Chem. , 2006, Vol. 61, NO. 10, pp. 1021-1025.

4. hugang, doctor's paper of Chinese university of science and technology, p25-27, fertilizer combination, 2005.

2) From L.2 HClO₄Preparation of [ NiL](ClO₄)₂：

Mix 11g Ni (AC)₂4H₂O and 21g of L.2 HClO₄Placing in a 500mL three-necked bottle, dissolving in 250mL methanol, heating and refluxing in a hot water bath for 3 hours, finally generating yellow precipitate, filtering, concentrating the filtrate in the hot water bath to the original volume l/2, standing overnight, and fully crystallizing to obtain yellow crystals. The yellow crystals were transferred to a Buchner funnel and washed with methanol, recrystallized from hot ethanol-water solution, and dried under vacuum to give 8g of [ NiL ]](ClO₄)₂Bright yellow crystals.

Reference documents:

1. N. F. Curtis, J. Chem. Soc. Dolton Tran. , 1972, Vol. 13, 1357.

2. hugang, doctor's paper of Chinese university of science and technology, p42-43, fertilizer combination, 2005.

The present discrimination method differs from the prior art in that the present invention employs "H₂SO₄ -KIO₃-[NiL](ClO₄)₂-malonic acid-H₂O₂The chemical oscillation system is used as a distinguishing solution, and sodium phosphite and sodium hypophosphite have different influences on potential oscillation maps of the distinguishing solution, so that the distinguishing of the sodium phosphite and the sodium hypophosphite is realized.

Sodium phosphite and sodium hypophosphite in a distinguishable concentration range of 5.0X 10 in a discriminating solution (chemical oscillation system)^-3-2.25×10^-2mol/L。

The concentration ranges that can be distinguished by the solutions to be distinguished are the optimum concentration ranges determined experimentally. In the concentration range, the difference of the influence of the sodium phosphite and the sodium hypophosphite on the distinguishing solution is very obvious, and the distinguishing is easy to observe and analyze and realize. In addition, the concentration ranges of the components in the discrimination solution (chemical oscillation system) are shown in table 1, and the optimum solution of the discrimination solution (chemical oscillation system) obtained through a plurality of experiments is shown in table 2:

table 1: concentration range of each component in chemical oscillation system

Sulfuric acid (mol/L)	Potassium iodate (mol/L)	[NiL](ClO4)2 (mol/L)	Malonic acid (mol/L)	Hydrogen peroxide (mol/L)
					0.0246468-0.025	0.0175-0.021	6.4875×10-4-8.65×10-4	0.125-0.165	1.35-1.45

Table 2: optimum concentration of each component in chemical oscillation system

Sulfuric acid (mol/L)	Potassium iodate (mol/L)	[NiL](ClO4)2(mol/L)	Malonic acid (mol/L)	Hydrogen peroxide (mol/L)
					0.025	0.01855	8.65×10-4	0.135	1.4

The specific experimental steps are as follows:

1. preparing a distinguishing solution according to the concentration range specified in table 1, inserting a prepared working electrode (platinum electrode) and a reference electrode (calomel electrode) into the solution, connecting the other end of the working electrode to a data collector (Go | LINK) through an Amplifier (Instrument Amplifier), connecting the other end of the working electrode to a computer, starting a loader lite program in the computer to set the collection time and the sampling speed, quickly clicking a start key to monitor the potential of the solution, and obtaining an acquired E-t curve (the curve of the potential value changing along with the time), namely a chemical potential oscillation map (at the moment, a sample to be detected is not added) to be used as a blank contrast. And (3) respectively and rapidly adding the solution of the sample to be distinguished to any one stable potential lowest point generated by oscillation in two groups of distinguishing solutions with the same component concentration as that in the blank control experiment, and realizing qualitative analysis of the sample to be distinguished according to different oscillation responses of the sample to be distinguished to a chemical oscillation system. The method comprises the following specific steps: if the chemical oscillation is inhibited after the solution to be distinguished is added, the oscillation is recovered along with a period of inhibition time, and meanwhile, the oscillation life is shortened due to the reduction of the chemical oscillation amplitude, the added sample to be distinguished is sodium phosphite; if the chemical oscillation amplitude is reduced after the solution to be distinguished is added, the oscillation life is shortened, but no inhibition time appears, and the added sample to be distinguished is sodium hypophosphite.

The basic parameters of the chemical potential oscillation spectrum include:

oscillation amplitude: the potential difference from one lowest potential to the next highest potential during oscillation.

Oscillation period: the time required from one lowest (high) potential to the next lowest (high) potential during oscillation.

The highest potential: the highest potential point of the system appears when the system oscillates stably.

Lowest potential: the lowest point of potential of the system appears when the system oscillates stably.

Inhibition time (t)_in): the time from the inhibition of oscillation after the liquid to be tested is added to the resumption of oscillation.

Oscillation life: the oscillation is from the beginning to the end of the oscillation.

Drawings

FIG. 1 is a vibration pattern of a discrimination solution (chemical oscillation system) in example 1 without adding a sample to be discriminated.

FIG. 2 shows that in example 1, 5.0X 10^-3And (3) after mol/L of sodium phosphite, obtaining an oscillation response spectrum by a chemical oscillation system.

FIG. 3 is a graph of example 1, with 5.0X 10^-3And (3) after mol/L of sodium hypophosphite, obtaining an oscillation response spectrum by a chemical oscillation system.

FIG. 4 is a vibration pattern of the discrimination solution (chemical oscillation system) in example 2 without adding the sample to be discriminated.

FIG. 5 is a graph of example 2, with 1.0X 10^-2And (3) after mol/L of sodium phosphite, obtaining an oscillation response spectrum by a chemical oscillation system.

FIG. 6 shows the addition of 1.0X 10 in example 2^-2And (3) after mol/L of sodium hypophosphite, obtaining an oscillation response spectrum by a chemical oscillation system.

FIG. 7 is a vibration pattern of the discrimination solution (chemical oscillation system) in example 3 when the sample to be discriminated is not added.

FIG. 8 is a graph of example 3, with the addition of 2.25X 10^-2And (3) after mol/L of sodium phosphite, obtaining an oscillation response spectrum by a chemical oscillation system.

FIG. 9 is a graph of example 3, with the addition of 2.25X 10^-2And (3) after mol/L of sodium hypophosphite, obtaining an oscillation response spectrum by a chemical oscillation system.

Detailed Description

Example 1:

this example demonstrates the feasibility of the method of distinguishing sodium phosphite from sodium hypophosphite of the present invention according to the following steps:

(1) preparing solution

Firstly, 98% concentrated sulfuric acid and distilled water are used to prepare 0.025mol/L sulfuric acid as stock solution, then 0.025mol/L sulfuric acid solution is used to prepare 0.14mol/L potassium iodate solution and 0.0173mol/L [ NiL ] solution](ClO₄)₂The solution, 2mol/L malonic acid solution and 4mol/L hydrogen peroxide solution. 16.0mL of a 0.025mol/L sulfuric acid solution, 5.3mL of a 0.14mol/L potassium iodate solution, and 2.0mL of 0.0173mol/L [ NiL ] were sequentially added to a 50mL beaker](ClO₄)₂Solution, 2.7mL of 2mol/L malonic acid solution and 14.0mL of 4mol/L hydrogen peroxide solution to ensure "H₂SO₄ - KIO₃ - [NiL](ClO₄)₂ -malonic acid-H₂O₂The concentrations of the components in the chemical oscillation system are 0.025mol/L sulfuric acid, 0.01855mol/L potassium iodate and [ NiL](ClO₄)₂ 8.65×10^-4mol/L, 0.135mol/L of malonic acid and 1.4mol/L of hydrogen peroxide;

meanwhile, distilled water is used as a solvent to prepare 1.0mol/L sodium phosphite solution and sodium hypophosphite solution respectively.

(2) Oscillation atlas

The potentiometric oscillation pattern of the chemical oscillation system was recorded by a computer equipped with the program logger lite, FIG. 1 showing the results of the measurement at typical concentrations (0.025 mol/L sulfuric acid, 0.01855mol/L potassium iodate, [ NiL ]](ClO₄)₂8.65×10^-4mol/L, 0.135mol/L of malonic acid and 1.4mol/L of hydrogen peroxide), and the above distinguishing solution is not added with the oscillation spectrum of the sample to be tested to be used as a blank control. Adding 200 μ L of 1.0mol/L sodium phosphite and sodium hypophosphite into two groups of discrimination solutions with the same concentration as above to make their concentration in the discrimination solution 5.0 × 10^-3mol/L, the time of each addition is at the 6 th potential lowest point of the oscillation map, and the obtained oscillation response maps are respectively shown in FIG. 2 and FIG. 3.

(3) Distinguishing

Sodium phosphite and sodium hypophosphite have different influences on a chemical oscillation system due to different reducibility. As can be seen from fig. 2 and fig. 3, the addition of sodium phosphite suppresses the chemical oscillation system, and the oscillation is resumed after a period of suppression time, and the oscillation life is shortened due to the reduction of the chemical oscillation amplitude; the addition of sodium hypophosphite reduces the amplitude of the chemical oscillation system, shortens the oscillation life, but has no inhibition time. From the above experiments, the distinction between sodium phosphite and sodium hypophosphite can be realized by comparing the change of the oscillation spectrum.

Taking two pre-prepared 1.0mol/L solutions of samples to be distinguished (one of the two solutions is a sodium phosphite solution, the other is a sodium hypophosphite solution, but the two solutions are not distinguished), marking one of the two solutions as a sample 1, and marking the other solution as a sample 2;

preparing two groups of chemical oscillation solutions with the same concentration of each component as the concentration, respectively collecting corresponding oscillation maps, and respectively adding 200 μ L of 1.0mol/L sample 1 and sample 2 at the 6 th potential lowest point to make their concentration in the discrimination solution 5.0 × 10^-3mol/L。

The analysis and comparison can show that: the addition of sample 1 suppressed the chemical oscillation system and resumed oscillation with a period of suppression time, while the chemical oscillation amplitude decreased the oscillation lifetime (the oscillation pattern corresponds to fig. 2 and does not correspond to fig. 3), while the addition of sample 2 decreased the chemical oscillation system amplitude and decreased the oscillation lifetime without the occurrence of suppression time (the oscillation pattern corresponds to fig. 3 and does not correspond to fig. 2). Therefore, the sample 1 is a sodium phosphite solution and the sample 2 is a sodium hypophosphite solution, so that the sodium phosphite solution and the sodium hypophosphite solution are distinguished.

Example 2:

this example demonstrates the feasibility of the method of distinguishing sodium phosphite from sodium hypophosphite of the present invention according to the following steps:

(1) preparing solution

Firstly, 98% concentrated sulfuric acid is used to prepare 0.025mol/L sulfuric acid as stock solution, then 0.025mol/L sulfuric acid solution is used to prepare 0.14mol/L potassium iodate solution and 0.0173mol/L [ NiL ] respectively](ClO₄)₂The solution, 2mol/L malonic acid solution and 4mol/L hydrogen peroxide solution; to a 50mL beaker was added 1 in sequence6.0mL of 0.025mol/L sulfuric acid solution, 5.2mL of 0.14mol/L potassium iodate solution, and 1.8mL of 0.0173mol/L [ NiL ]](ClO₄)₂Solution, 2.8mL of 2mol/L malonic acid solution, 14.2mL of 4mol/L hydrogen peroxide solution to ensure "H₂SO₄ - KIO₃ - [NiL](ClO₄)₂ -malonic acid-H₂O₂The concentrations of each component in the chemical oscillation system are 0.025mol/L sulfuric acid, 0.0182mol/L potassium iodate and [ NiL](ClO₄)₂ 7.785×10^-4mol/L, 0.14mol/L of malonic acid and 1.42mol/L of hydrogen peroxide;

meanwhile, distilled water is used as a solvent to prepare 1.0mol/L sodium phosphite solution and sodium hypophosphite solution respectively.

(2) Oscillation atlas

The potential oscillation spectrum of the chemical oscillation system is recorded by a computer provided with a logger lite program, and the difference between the oscillation responses generated by the sodium phosphite and the sodium hypophosphite is inspected. FIG. 4 is a graph of the oscillation spectrum of a discrimination solution without adding a test sample as a blank. Adding 400 mul of 1.0mol/L sodium phosphite solution and sodium hypophosphite solution into two groups of distinguishing solutions with the same component concentration as the above concentration respectively to ensure that the concentrations of the sodium phosphite solution and the sodium hypophosphite solution in the distinguishing solutions are 1.0 multiplied by 10^{- 2}mol/L, the time of each addition is at the 6 th potential lowest point of the oscillation map, and the obtained oscillation response maps are respectively shown in FIG. 5 and FIG. 6.

(3) Distinguishing

Sodium phosphite and sodium hypophosphite have different influences on a chemical oscillation system due to different reducibility. Comparing fig. 5 and fig. 6, it can be seen that the addition of sodium phosphite suppresses the chemical oscillation system, and the oscillation is resumed after a period of suppression time, and the oscillation life is shortened due to the reduction of the chemical oscillation amplitude; the addition of sodium hypophosphite reduces the amplitude of the chemical oscillation system, shortens the oscillation life, but has no inhibition time. From the above experiments, the distinction between sodium phosphite and sodium hypophosphite can be realized by comparing the change of the oscillation spectrum.

Taking two pre-prepared 1.0mol/L solutions of samples to be distinguished (one is a sodium phosphite solution, the other is a sodium hypophosphite solution, but the two are not identified), marking one of the two solutions as a sample 1, and marking the other as a sample 2;

preparing two groups of chemical oscillation solutions with the same component concentration as the component concentration, respectively collecting corresponding oscillation maps, and respectively adding 400 mu L of sample 1 and sample 2 of 1.0mol/L at the 6 th potential lowest point to ensure that the concentrations of the two groups of chemical oscillation solutions in the distinguishing solutions are 1.0 x 10^-2mol/L。

The analysis and comparison can show that: the addition of sample 1 suppressed the chemical oscillation system and resumed oscillation with a period of suppression time, while the chemical oscillation amplitude decreased the oscillation lifetime (the oscillation pattern corresponds to fig. 5 and does not correspond to fig. 6), while the addition of sample 2 decreased the chemical oscillation system amplitude and decreased the oscillation lifetime without the occurrence of suppression time (the oscillation pattern corresponds to fig. 6 and does not correspond to fig. 5). Therefore, the sample 1 is a sodium phosphite solution and the sample 2 is a sodium hypophosphite solution, so that the sodium phosphite solution and the sodium hypophosphite solution are distinguished.

Example 3:

the feasibility of the method for distinguishing sodium phosphite from sodium hypophosphite is verified according to the following steps:

(1) preparing solution

Firstly, 98% concentrated sulfuric acid and distilled water are used to prepare 0.025mol/L sulfuric acid as stock solution, then 0.025mol/L sulfuric acid solution is used to prepare 0.14mol/L potassium iodate solution and 0.0173mol/L [ NiL ] solution](ClO₄)₂The solution, 2mol/L malonic acid solution and 4mol/L hydrogen peroxide solution. To a 50mL beaker were added 15.5mL of a 0.025mol/L sulfuric acid solution, 5.3mL of a 0.14mol/L potassium iodate solution, and 2.0mL of 0.0173mol/L [ NiL ] in that order](ClO₄)₂Solution, 3.0mL of 2mol/L malonic acid solution and 14.2mL of 4mol/L hydrogen peroxide solution to ensure "H₂SO₄ - KIO₃ - [NiL](ClO₄)₂ -malonic acid-H₂O₂The concentrations of the components in the chemical oscillation system are 0.025mol/L sulfuric acid, 0.01855mol/L potassium iodate and [ NiL](ClO₄)₂ 8.65×10^-4mol/L, 0.15mol/L of malonic acid, 1.42mol/L of hydrogen peroxidemol/L；

Meanwhile, distilled water is used as a solvent to prepare 1.0mol/L sodium phosphite solution and sodium hypophosphite solution respectively.

(2) Oscillation atlas

The potential oscillation spectrum of the chemical oscillation system is recorded by a computer equipped with a logger lite program, and fig. 7 is an oscillation spectrum in which the above-mentioned discrimination solution is not added to the sample to be measured, for blank control. Adding 900 μ L of 1.0mol/L sodium phosphite solution and sodium hypophosphite solution into two groups of discrimination solutions with the same concentration as the above components, respectively, so that the concentrations in the discrimination solutions are 2.25 × 10^-2mol/L, the time of each addition is at the 6 th potential lowest point of the oscillation map, and the obtained oscillation response maps are respectively shown in figures 8 and 9.

(3) Distinguishing

Sodium phosphite and sodium hypophosphite have different influences on a chemical oscillation system due to different reducibility. Comparing fig. 8 and fig. 9, it can be seen that the addition of sodium phosphite suppresses the chemical oscillation system, and the oscillation is resumed after a period of suppression time, and the oscillation life is shortened due to the reduction of the chemical oscillation amplitude; the addition of sodium hypophosphite reduces the amplitude of the chemical oscillation system, shortens the oscillation life, but has no inhibition time. From the above experiments, the distinction between sodium phosphite and sodium hypophosphite can be realized by comparing the change of the oscillation spectrum.

Taking two pre-prepared 1.0mol/L solutions of samples to be distinguished (one of the two solutions is a sodium phosphite solution, the other is a sodium hypophosphite solution, but the two solutions are not distinguished), marking one of the two solutions as a sample 1, and marking the other solution as a sample 2;

preparing two groups of chemical oscillation solutions with the same component concentration as the component concentration, respectively collecting corresponding oscillation maps, and respectively adding 900 mu L of sample 1 and sample 2 of 1.0mol/L at the 6 th potential lowest point to ensure that the concentrations of the two groups of chemical oscillation solutions in the distinguishing solutions are 2.25 multiplied by 10^-2mol/L。

The analysis and comparison can show that: the addition of sample 1 suppressed the chemical oscillation system and resumed oscillation with a period of suppression time, while the chemical oscillation amplitude decreased the oscillation lifetime (the oscillation pattern corresponds to fig. 8 and does not correspond to fig. 9), while the addition of sample 2 decreased the chemical oscillation system amplitude and decreased the oscillation lifetime without the occurrence of suppression time (the oscillation pattern corresponds to fig. 9 and does not correspond to fig. 8). Therefore, the sample 1 is a sodium phosphite solution and the sample 2 is a sodium hypophosphite solution, so that the sodium phosphite solution and the sodium hypophosphite solution are distinguished.

It can be seen from the above examples that sodium phosphite solutions and sodium hypophosphite solutions of smaller or larger concentrations can also be distinguished by the process according to the invention.