阅读说明：本技术 一种区分磷的不同价态含氧酸磷酸及亚磷酸的方法 (Method for distinguishing different valence states of phosphorus, oxygen-containing acid phosphoric acid and phosphorous acid ) 是由 胡刚 周彦珂 张兰兰 于 2020-10-09 设计创作，主要内容包括：一种区分磷的不同价态含氧酸磷酸及亚磷酸的方法,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,根据磷酸及亚磷酸对该体系振荡的影响不同,从而实现磷酸及亚磷酸的区分。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磷酸及亚磷酸,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 phosphorus, including phosphoric acid and phosphorous acid, 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 phosphoric acid and the phosphorous acid are distinguished according to different influences of the phosphoric acid and the phosphorous acid on oscillation of the system. The potential oscillation spectrum provided by the distinguishing method has intuitiveness, can conveniently and quickly distinguish phosphoric acid and phosphorous acid, and has the advantages of simple equipment, high accuracy and easy operation and observation.)

1. A method for distinguishing different valence states of phosphorus, including phosphoric acid and phosphorous acid, 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 for distinguishing the solution, the potential variation potential oscillation spectrum of the potential of the chemical oscillation system along with the time is recorded, the solutions of phosphoric acid or phosphorous acid to be distinguished samples are respectively added into two groups of distinguishing solutions at any stable potential lowest point generated by oscillation, and the distinguishing of the samples to be distinguished is realized according to the different influences of the samples to be distinguished on the chemical oscillation system: if the solution to be distinguished is added without influencing a chemical oscillation system, the added sample to be distinguished is phosphoric acid; 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 the oscillation period is increased, the added sample to be distinguished is phosphorous acid;

[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: 0.0246435-0.025mol/L sulfuric acid, 0.0175-0.022mol/L potassium iodate and [ NiL ]](ClO₄)₂6.4865×10^-4-8.65×10^-4mol/L, 0.125-0.175mol/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, 0.0175mol/L potassium iodate and [ NiL ]](ClO₄)₂ 7.785×10^-4mol/L, 0.125mol/L of malonic acid and 1.45mol/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 oxyacid phosphoric acid and phosphorous acid with different valence states of phosphorus by a catalytic chemical oscillation system is disclosed, wherein a ligand L is 5, 7, 7, 12, 14, 14-hexamethyl-1, 4, 8, 11-tetraazacyclotetradecyl-4, 11-diene, and belongs to the field of qualitative analysis chemistry.

Background

Phosphoric acid and phosphorous acid are oxyacids corresponding to the same element, and each plays a very important role in their respective fields. Phosphoric acid, chemical formula H₃PO₄It is a common inorganic acid, which is a medium strong acid. Phosphoric acid is used mainly in the pharmaceutical, food, fertilizer and other industries, including as rust inhibitors, food additives, dental and orthopedic, EDIC corrosives, electrolytes, fluxes, dispersants, industrial corrosives, fertilizer raw materials and component household cleaning products. It can also be used as a chemical agent, and phosphate is a nutrient for all life forms. Phosphorous acid, molecular formula: h₃PO₃Phosphorous acid is mainly used as a reducing agent, a nylon brightener, and also as a phosphite raw material, an agricultural chemical intermediate, and an organic compoundRaw materials of phosphorus water treatment agent.

The two methods of distinguishing which have been reported so far are chemical methods: 1. heating, phosphorous acid alkaline condition is easy to disproportionate, and gas (phosphine) with rotten garlic smell is generated. 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. 2. Adding an oxidizing agent such as Ag⁺The black precipitate is generated by phosphorous acid, which is easy to precipitate Ag because of its strong reducibility⁺Reducing the silver into silver Ag. Although the method can also realize the distinction between the two, the detection limit is higher, and the method has limited application for low-concentration solution. 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)

Structures of phosphoric acid and phosphorous acid of formula (I).

Disclosure of Invention

The invention aims to provide a novel, convenient and quick distinguishing method for phosphoric acid and phosphorous acid, namely application of [ NiL](ClO₄)₂The method for distinguishing phosphoric acid from phosphorous acid by a catalytic chemical oscillation system is an electrochemical oscillation system method developed based on the acute response of the complex-catalyzed chemical oscillation system to the phosphoric acid and the phosphorous acid. Specifically, samples (phosphoric acid and phosphorous acid) to be distinguished with the same concentration 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 solution to be distinguished is added without influencing a chemical oscillation system, the added sample to be distinguished is phosphoric acid; 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 the oscillation period is increased, the added sample to be distinguished is phosphorous acid.

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

the invention provides a distinguishing method for phosphoric acid and phosphorous acid, 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 for distinguishing solutions, potential oscillation maps of the chemical oscillation system are recorded, solutions of phosphoric acid and phosphorous acid samples to be distinguished are respectively added into two groups of distinguishing solutions (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 solution to be distinguished is added without influencing a chemical oscillation system, the added sample to be distinguished is phosphoric acid; and 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 the oscillation period is increased, the added sample to be distinguished is phosphorous acid.

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)₂Structure of (1)

The structure of the complex is very similar to that of key structure porphyrin ring of myoglobin, hemoglobin, chlorophyll and some metalloenzymes in a living body, and the structure is expressed by [ NiL](ClO₄)₂The catalyzed chemical oscillatory reaction is similar to biochemical oscillations within plant and animal cells. Therefore, the bodyHas stable amplitude, long oscillation life and sharp response to phosphoric acid and phosphorous acid.

[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 500mL three-necked flask, dissolving in 250mL methanol, heating and refluxing in hot water bath for 3 hr to obtain yellow precipitate, filtering,The filtrate was concentrated to the original volume l/2 in a hot water bath, left overnight and crystallized well to give 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 phosphoric acid and phosphorous acid are distinguished by different influences of the phosphoric acid and the phosphorous acid on a potential oscillation spectrum of the distinguishing solution.

Phosphoric acid and phosphorous acid, the distinguishable concentration range in the distinguishing solution (chemical oscillation system) being 5.0X 10^-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 phosphoric acid and phosphorous acid on the distinguishing solution is very obvious, and the distinguishing solution is easy to observe and analyze and realize distinguishing. 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)
					0.0246435-0.025	0.0175-0.022	6.4865×10-4-8.65×10-4	0.125-0.175	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	0.0175	7.785×10-4	0.125	1.45

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 solution to be distinguished is added, the chemical oscillation system is not influenced, and the added sample to be distinguished is phosphoric acid; and 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 the oscillation period is increased, the added sample to be distinguished is phosphorous acid.

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 phosphoric acid, chemically oscillating the oscillation response spectrum obtained by the system.

FIG. 3 is a graph of example 1, with 5.0X 10^-3And (3) after mol/L of phosphorous acid, chemically oscillating the oscillation response diagram obtained by the 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 phosphoric acid, chemically oscillating the oscillation response spectrum obtained by the system.

FIG. 6 shows the addition of 1.0X 10 in example 2^-2And (3) after mol/L of phosphorous acid, chemically oscillating the oscillation response diagram obtained by the 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 phosphoric acid, chemically oscillating the oscillation response spectrum obtained by the system.

FIG. 9 is a graph of example 3, with the addition of 2.25X 10^-2And (3) after mol/L of phosphorous acid, chemically oscillating the oscillation response diagram obtained by the system.

Detailed Description

Example 1:

this example demonstrates the feasibility of the method of differentiating between phosphoric acid and phosphorous acid according to the invention as follows:

(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, 5.0mL of a 0.14mol/L potassium iodate solution, and 1.8mL of 0.0173mol/L [ NiL ] were sequentially added to a 50mL beaker](ClO₄)₂Solution, 2.5mL of 2mol/L malonic acid solution and 14.5mL 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, 0.0175mol/L potassium iodate and [ NiL](ClO₄)₂ 7.785×10^-4mol/L, 0.125mol/L of malonic acid and 1.45mol/L of hydrogen peroxide;

meanwhile, distilled water is used as a solvent to prepare a phosphoric acid solution and a phosphorous acid solution of 1.0mol/L respectively.

(2) Oscillation atlas

The potential oscillation pattern of the chemical oscillation system is recorded by a computer equipped with a logger lite program, FIG. 1 at typical concentration (0.025 sulfuric acid)mol/L, potassium iodate 0.0175mol/L, [ NiL](ClO₄)₂7.785×10^-4mol/L, 0.125mol/L of malonic acid and 1.45mol/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. To two groups of discrimination solutions each having the same concentration as the above, 200. mu.L of 1.0mol/L phosphoric acid and phosphorous acid were added, respectively, so that the concentrations thereof in the discrimination solutions were each 5.0X 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

Phosphoric acid and phosphorous acid have different effects on a chemical oscillation system due to their different reductibility. As can be seen from the comparison of FIG. 2 and FIG. 3, the addition of phosphoric acid has no effect on the chemical oscillation system; phosphorous acid is added, so that a chemical oscillation system is inhibited, oscillation is recovered along with a period of inhibition, and then the oscillation period is increased. From the above experiments, it can be known that phosphoric acid and phosphorous acid can be distinguished by comparing the change of the oscillation spectrum.

Taking two 1.0mol/L solutions of samples to be distinguished (one of which is a phosphoric acid solution and the other is a phosphorous acid solution, but the two solutions are not distinguished) prepared in advance, and marking one of the solutions as a sample 1 and the other 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 had no effect on the chemical oscillation system (oscillation pattern corresponds to fig. 2 and does not correspond to fig. 3), while the addition of sample 2 suppressed the chemical oscillation system, resumed oscillation with a period of suppression, and then increased the oscillation period (oscillation pattern corresponds to fig. 3 and does not correspond to fig. 2). Thus, sample 1 is a phosphoric acid solution and sample 2 is a phosphorous acid solution, thereby achieving the distinction between the phosphoric acid solution and the phosphorous acid solution.

Example 2:

this example demonstrates the feasibility of the method of differentiating between phosphoric acid and phosphorous acid according to the invention as follows:

(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; 16.0mL of a 0.025mol/L sulfuric acid solution, 5.2mL 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, 2.8mL of 2mol/L malonic acid solution, 14mL 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 8.65×10^-4mol/L, 0.14mol/L of malonic acid and 1.4mol/L of hydrogen peroxide;

meanwhile, distilled water is used as a solvent to prepare a phosphoric acid solution and a phosphorous acid solution of 1.0mol/L respectively.

(2) Oscillation atlas

The potential oscillation spectrum of the above chemical oscillation system was recorded by a computer equipped with a logger lite program to examine the difference between the oscillation responses produced by phosphoric acid and phosphorous acid. FIG. 4 is a graph of the oscillation spectrum of a discrimination solution without adding a test sample as a blank. Adding 400 mu L of 1.0mol/L phosphoric acid solution and phosphorous acid solution into two groups of distinguishing solutions with the same component concentration as the component concentration, so that the concentrations of the two groups of distinguishing solutions are 1.0 multiplied by 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 FIG. 5 and FIG. 6.

(3) Distinguishing

Phosphoric acid and phosphorous acid have different effects on a chemical oscillation system due to their different reductibility. Comparing fig. 5 and fig. 6, it can be seen that the addition of phosphoric acid has no effect on the chemical oscillation system; phosphorous acid is added, so that a chemical oscillation system is inhibited, oscillation is recovered along with a period of inhibition, and then the oscillation period is increased. From the above experiments, it can be known that phosphoric acid and phosphorous acid can be distinguished by comparing the change of the oscillation spectrum.

Taking two 1.0mol/L solutions of samples to be distinguished (one of which is a phosphoric acid solution and the other is a phosphorous acid solution, but the two solutions are not identified) prepared in advance, and marking one of the solutions as a sample 1 and 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 had no effect on the chemical oscillation system (oscillation pattern corresponding to fig. 5 and not to fig. 6), while the addition of sample 2 suppressed the chemical oscillation system, resumed oscillation with a period of suppression time, and then increased the oscillation period (oscillation pattern corresponding to fig. 6 and not to fig. 5). Thus, sample 1 is a phosphoric acid solution and sample 2 is a phosphorous acid solution, thereby achieving the distinction between the phosphoric acid solution and the phosphorous acid solution.

Example 3:

this example verifies the feasibility of the method for differentiating between phosphoric acid and phosphorous acid according to the invention by 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. 16mL of a 0.025mol/L sulfuric acid solution, 5.0L of a 0.14mol/L potassium iodate solution, and 1.8mL of 0.0173mol/L [ NiL ] were sequentially added to a 50mL beaker](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 each component in the chemical oscillation system are 0.025mol/L sulfuric acid, 0.0175mol/L potassium iodate and [ NiL](ClO₄)₂ 7.785×10^-4mol/L, 0.15mol/L of malonic acid and 1.42mol/L of hydrogen peroxide;

meanwhile, distilled water is used as a solvent to prepare a phosphoric acid solution and a phosphorous acid solution of 1.0mol/L 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. To two groups of discrimination solutions each having the same concentration as the above, 900. mu.L of 1.0mol/L phosphoric acid solution and phosphorous acid solution were added, respectively, so that the concentrations thereof in the discrimination solutions were each 2.25X 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

Phosphoric acid and phosphorous acid have different effects on a chemical oscillation system due to their different reductibility. Comparing fig. 8 and fig. 9, it can be seen that the addition of phosphoric acid has no effect on the chemical oscillation system; phosphorous acid is added, so that a chemical oscillation system is inhibited, oscillation is recovered along with a period of inhibition, and then the oscillation period is increased. From the above experiments, it can be known that phosphoric acid and phosphorous acid can be distinguished by comparing the change of the oscillation spectrum.

Taking two 1.0mol/L solutions of samples to be distinguished (one of which is a phosphoric acid solution and the other is a phosphorous acid solution, but the two solutions are not distinguished) prepared in advance, and marking one of the solutions as a sample 1 and 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 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 had no effect on the chemical oscillation system (oscillation pattern corresponding to fig. 8 and not to fig. 9), while the addition of sample 2 suppressed the chemical oscillation system, resumed oscillation with a period of suppression time, and then increased the oscillation period (oscillation pattern corresponding to fig. 9 and not to fig. 8). Thus, sample 1 is a phosphoric acid solution and sample 2 is a phosphorous acid solution, thereby achieving the distinction between the phosphoric acid solution and the phosphorous acid solution.

As can be seen from the above examples, smaller or greater concentrations of phosphoric acid solution and phosphorous acid solution can also be distinguished by the method of the present invention.