阅读说明：本技术 一种山梨醇螯合钾肥的制备及检测方法 (Preparation and detection method of sorbitol chelated potassium fertilizer ) 是由 颜冬云 孙伟 李鹏超 杨淑静 魏倩倩 李腾升 崔玉照 谭慧婷 韩传浩 于 2021-09-06 设计创作，主要内容包括：本发明属于螯合肥制备及检测技术领域,涉及一种山梨醇螯合钾肥的制备及检测方法,山梨醇螯合钾肥以山梨醇、钾盐和去离子水或软化水为原料,制备方法包括溶解、混合和螯合；检测方法是先处理山梨醇螯合肥溶液得到山梨醇螯合钾沉淀,然后分别对山梨醇螯合钾沉淀溶液、山梨醇溶液、钾盐溶液和山梨醇钾盐混合溶液进行紫外-可见光谱扫描,再通过对比各扫描图谱,通过最大吸收峰的变化证明山梨醇螯合钾新物质的生成；其制备方法简单,耗能低、产品品质好,实现了对钾的高效利用,从源头上解决了传统农业生产过程中产生的能源浪费及面源污染问题；其检测方法可定性证明山梨醇螯合钾的生成,从根本上保证了本发明涉及的糖醇螯合钾的研发与制备具有意义。(The invention belongs to the technical field of preparation and detection of chelated fertilizers, and relates to a preparation and detection method of a sorbitol chelated potassium fertilizer, wherein the sorbitol chelated potassium fertilizer takes sorbitol, potassium salt and deionized water or softened water as raw materials, and the preparation method comprises the steps of dissolving, mixing and chelating; the detection method comprises the steps of firstly treating a sorbitol chelated fertilizer solution to obtain a sorbitol chelated potassium precipitate, then respectively carrying out ultraviolet-visible spectrum scanning on the sorbitol chelated potassium precipitate solution, a sorbitol solution, a potassium salt solution and a sorbitol potassium salt mixed solution, and then comparing all scanning maps to prove the generation of a new sorbitol chelated potassium substance through the change of a maximum absorption peak; the preparation method is simple, the energy consumption is low, the product quality is good, the high-efficiency utilization of potassium is realized, and the problems of energy waste and non-point source pollution generated in the traditional agricultural production process are solved from the source; the detection method can qualitatively prove the generation of the sorbitol chelated potassium, and fundamentally ensures that the research and development and preparation of the sugar alcohol chelated potassium have significance.)

1. The preparation method of the sorbitol chelated potassium fertilizer is characterized by comprising the following raw materials: sorbitol, potassium salt and deionized water or softened water, wherein the potassium salt is one of potassium acetate, potassium nitrate and potassium chloride; the preparation method comprises the following specific steps:

(1) dissolving: adding deionized water or softened water into a reaction kettle, setting the water bath temperature to be 50-90 ℃, heating at constant temperature, adding sorbitol into the reaction kettle after the temperature is stable, heating at constant temperature, continuously stirring until the sorbitol is completely dissolved into the deionized water or softened water, and obtaining a mixed alcohol water solution, wherein the solution is in a clear and transparent state;

(2) mixing: adding potassium salt into the mixed alcohol aqueous solution prepared in the step (1), keeping constant-temperature water bath heating, fully stirring until the potassium salt is completely dissolved, and after fully mixing, enabling the solution to be in a clear and transparent state to prepare a mixed solution;

(3) chelating: and (3) heating the mixed solution prepared in the step (2) in a constant-temperature water bath, stirring the mixed solution to perform chelation reaction, keeping the temperature of the water bath at 50-90 ℃, reacting for 0.5-1 h, taking out the reaction kettle after the reaction is finished, standing the reaction kettle, and cooling the reaction kettle to room temperature at room temperature to obtain the sorbitol chelated potassium fertilizer.

2. The preparation method of the sorbitol chelated potassium fertilizer as claimed in claim 1, wherein the sorbitol 15-30 parts, deionized water or demineralized water 10-20 parts, and the potassium salt is one of potassium acetate 200-300 parts, potassium nitrate 5-15 parts, and potassium chloride 5-15 parts.

3. A method for qualitatively detecting the sorbitol chelated potassium fertilizer obtained by the preparation method of claim 1 based on an ultraviolet-visible spectrophotometry, which is characterized by comprising the following specific detection steps:

(1) preparing a detection solution: collecting the sorbitol chelated potassium fertilizer solution for later use; diluting sorbitol and potassium salt used for preparing the sorbitol chelated potassium fertilizer by 100 times with deionized water or softened water respectively to prepare separate solutions for later use; preparing sorbitol and potassium salt used for preparing the sorbitol chelated potassium fertilizer into a mixed solution, and then diluting the mixed solution by 100 times with deionized water or softened water to prepare a separate solution for later use;

(2) treating a sorbitol chelated potassium fertilizer solution: adding a sorbitol chelated potassium fertilizer solution sample into a centrifugal tube, taking absolute ethyl alcohol and acetone as extracting agents, adding a proper amount of extracting agents into the centrifugal tube, heating the centrifugal tube in water bath at 60 ℃ for 30 minutes to fully dissolve the sorbitol chelated potassium fertilizer, standing the centrifugal tube at room temperature for 5 minutes, centrifuging the centrifugal tube at the rotating speed of 6000 r/min for 20 minutes, pouring supernatant in the centrifugal tube, continuously adding the extracting agents, centrifuging the supernatant at the rotating speed of 6000 r/min for 20 minutes, repeating the steps for 3-5 times to completely dissolve reactants which are not chelated in the sorbitol chelated potassium precipitate into the supernatant, diluting 100 times of the sorbitol chelated potassium precipitate obtained after centrifuging for multiple times with deionized water or softened water to prepare an independent solution for later use;

(3) and (3) determination: respectively carrying out ultraviolet-visible spectrum scanning on the sorbitol solution, the potassium salt solution and the mixed solution prepared in the step (1) and the sorbitol chelated potassium precipitation solution obtained by the step (2) within the wavelength range of 190 nm-230 nm by using an ultraviolet-visible spectrophotometer to obtain a detailed scanning map of each solution;

(4) and (3) detection: and (4) comparing and analyzing the scanning maps of the solutions by using the detailed scanning maps of the solutions obtained in the step (3), eliminating the interference of alcohol by using the scanning map of the sorbitol solution, eliminating the interference of potassium salt by using the scanning map of the potassium salt solution, comprehensively comparing the scanning maps of the solutions, and indirectly proving the generation of the new sorbitol chelated potassium substance through the change of the maximum absorption peak.

4. The method for qualitatively detecting the sorbitol chelated potassium fertilizer based on the ultraviolet-visible spectrophotometry as claimed in claim 3, wherein the volume ratio of the absolute ethyl alcohol to the acetone is 1:1-1: 2.

The technical field is as follows:

the invention belongs to the technical field of preparation and detection of chelated fertilizers, and relates to a sugar alcohol chelated fertilizer in an agricultural fertilizer, in particular to a preparation and detection method of a sorbitol chelated potassium fertilizer.

Background art:

china is a traditional agricultural big country, the planting area is large, the strength is high, a large amount of chemical fertilizers need to be applied in the production process, a large amount of problems of soil hardening, acidification and the like are caused by the large amount of application of the traditional fertilizers, and the development and the use of novel fertilizers are urgent. In the seventies of the twentieth century, scientists found sugar alcohol substances in phloem juice of plants, and by the beginning of the twenty-first century, sugar alcohol-series fertilizer products using sugar alcohol as an element carrier began to be introduced to the international market. The sugar alcohol chelated fertilizer is used as a high-quality foliar fertilizer, and has good nutrient transfer and absorption, but the development of the sugar alcohol chelated fertilizer in China is late, and related product patents are few. The sugar alcohol chelated potassium fertilizer is a stable substance with a five-membered ring or six-membered ring structure and the like generated by carrying out a chelation reaction on hydroxyl of sugar alcohol after dehydrogenation and potassium ions, and has the advantages of good stability and high utilization rate. The sugar alcohol is used as a polyhydroxy compound, is a primary product of photosynthesis, can carry mineral nutrients to be rapidly transported in the phloem of the plant, and has strong transportation capacity and good transportation effect. The sugar alcohol can improve the stress resistance of plants in plants, strengthen the differentiation and regeneration capacity of callus, and ensure that chelated products are stable due to the multidentation of the sugar alcohol on the structure, and the chelated products are easy to degrade and release nutrients when entering the plants, thereby promoting the absorption and utilization of the plants. The cell is the basic unit of plant, the division, enlargement and differentiation of cell into tissue with various special functions are the basis of the growth of all organisms, and during the growth and development of the plant, potassium element plays an important role. Sufficient nutrition and reproductive growth are the basis for obtaining high yield and high harvest of crops, sufficient potassium supply is beneficial to the growth of organs of the crops in different growth stages, the photosynthetic strength of leaves and the transportation efficiency of assimilation products are improved, more nutrient substances are transferred to fruits, and the yield of the crops is improved. In addition, potassium is used as a quality element of crops, and plays an important role in improving the protein content of the crops, reducing the sugar-acid ratio and the like. Under the carrying of sorbitol, the chelated potassium can be better transported in plants, and the potassium absorption of crops is promoted. In addition, the increase of the potassium content in crops enables people to obtain benefits after eating the crops, the potassium is one of important cations of human bodies, is one of macroelements in the human bodies, and has important functions in the aspects of maintaining the normal metabolism of sugar and protein, the normal osmotic pressure of cells, the excitability and normal function of neuromuscular, the normal function of cardiac muscle, the normal acid-base balance inside and outside cells, reducing blood pressure and the like. Therefore, the spraying of the chelated potassium fertilizer can better promote the absorption of potassium by crops, and the ultimate benefit is to human beings.

In the prior art, Chinese patent CN112552111A discloses a secondary element water-soluble fertilizer and a preparation method thereof, wherein the water-soluble fertilizer comprises the following components in parts by weight: 77.8 parts of calcium nitrate tetrahydrate, 7 parts of magnesium nitrate hexahydrate, 3 parts of polypeptide chelated potassium, 4.9 parts of sorbitol, 2.4 parts of glycerol and 4.9 parts of softened water. Although the invention solves the problem of easy precipitation of common water-soluble fertilizers, the adding amount of the polypeptide chelated potassium is less, the potassium is only added as a supplementary element, meanwhile, various alcohols are added in the invention, so that the reaction system can possibly generate the chelated potassium, the generating amount is less, the concentration of the chelated potassium is not enough, the polypeptide chelated potassium is only one of the reactants, and the chelating agent is of polypeptide type, is different from the sugar alcohol chelating agent in type and has different properties. Chinese patent CN102408347A discloses a preparation method of L-aspartic acid chelated potassium dihydrate, wherein the chelated potassium takes L-aspartic acid and potassium carbonate or potassium hydroxide as raw materials. The method comprises the specific steps of adding deionized water into a reaction container, heating to a certain temperature, adding calculated amounts of L-aspartic acid and potassium carbonate or potassium hydroxide, wherein the weight-volume ratio (Kg: L) of reactant L-aspartic acid to deionized water is 0.1-0.3: 1, and correcting the pH range to be 6.0-8.0 after reaction liquid is clarified. The chelating agent used in the method is amino acid, and the prepared crystal is directly separated without detection, so that the property of the product cannot be determined.

At present, the research on chelate fertilizers of medium and trace elements is more, the research on chelate fertilizers of potassium as a major element is less, the development is slower, particularly, the research on chelate fertilizers of sugar alcohol series is less, related detection fields are still lacked at present, and the preparation method of potassium sorbate and the method for qualitatively analyzing the products need to be researched and developed, so that the product obtained by the preparation method is the potassium sorbate.

The invention content is as follows:

the invention aims to overcome the defects in the prior art, provides the preparation method of sorbitol potassium chelate, which has the advantages of simple production process, low energy consumption and good quality, follows the development of green ecological agriculture, realizes the aims of high-efficiency utilization of potassium and environmental friendliness, and solves the problems of energy waste and surface source pollution generated in the traditional agricultural production process from the source.

In order to realize the purpose, the invention relates to a preparation method of a sorbitol chelated potassium fertilizer, which is prepared from the following raw materials: sorbitol, potassium salt and deionized water or softened water, wherein the potassium salt is one of potassium acetate, potassium nitrate and potassium chloride;

the preparation method comprises the following specific steps:

(1) dissolving: adding deionized water or softened water into a reaction kettle, setting the water bath temperature to be 50-90 ℃, heating at constant temperature, adding sorbitol into the reaction kettle after the temperature is stable, heating at constant temperature, continuously stirring until the sorbitol is completely dissolved into the deionized water or softened water, and obtaining a mixed alcohol water solution, wherein the solution is in a clear and transparent state;

(2) mixing: adding potassium salt into the mixed alcohol aqueous solution prepared in the step (1), keeping constant-temperature water bath heating, fully stirring until the potassium salt is completely dissolved, and after fully mixing, enabling the solution to be in a clear and transparent state to prepare a mixed solution;

(3) chelating: and (3) heating the mixed solution prepared in the step (2) in a constant-temperature water bath, stirring the mixed solution to perform chelation reaction, keeping the temperature of the water bath at 50-90 ℃, reacting for 0.5-1 h, taking out the reaction kettle after the reaction is finished, standing the reaction kettle, and cooling the reaction kettle to room temperature at room temperature to obtain the sorbitol chelated potassium fertilizer.

Further, according to the parts by weight, 15-30 parts of sorbitol, 10-20 parts of deionized water or softened water, and one of 200-300 parts of potassium acetate, 5-15 parts of potassium nitrate and 5-15 parts of potassium chloride as potassium salt.

The invention also provides a method for qualitatively detecting the sorbitol chelated potassium fertilizer obtained by the preparation method based on an ultraviolet-visible spectrophotometry, which comprises the following specific detection steps:

preparing a detection solution: collecting the sorbitol chelated potassium fertilizer solution for later use; diluting sorbitol and potassium salt used for preparing the sorbitol chelated potassium fertilizer by 100 times with deionized water or softened water respectively to prepare separate solutions for later use; preparing sorbitol and potassium salt used for preparing the sorbitol chelated potassium fertilizer into a mixed solution, and then diluting the mixed solution by 100 times with deionized water (or softened water) to prepare a separate solution for later use;

treating the sorbitol chelated potassium fertilizer solution: weighing 4g of a sorbitol chelated potassium fertilizer solution sample, adding the sorbitol chelated potassium fertilizer solution sample into a 50mL centrifuge tube, adding a proper amount of an extracting agent into the centrifuge tube by taking absolute ethyl alcohol and acetone as extracting agents, heating the mixture in a water bath at 60 ℃ for 30 minutes to fully dissolve the sorbitol chelated potassium fertilizer, standing the mixture at room temperature for 5 minutes, centrifuging the mixture at a rotating speed of 6000 r/min for 20 minutes, pouring supernatant in the centrifuge tube, continuously adding the extracting agent into the centrifuge tube, centrifuging the mixture at 6000 r/min for 20 minutes, repeating the steps for 3 to 5 times to completely dissolve reactants which are not chelated in the sorbitol chelated potassium precipitate into supernatant, collecting the supernatant after the last centrifugation, carrying out color comparison by using an ultraviolet-visible spectrophotometer when the added extracting agent is taken as a reference, and finishing the centrifugation when the reading of the ultraviolet-visible spectrophotometer is stable and close to zero, diluting the sorbitol chelated potassium precipitate obtained after multiple centrifugations by 100 times with deionized water or softened water to prepare an independent solution for later use;

determination: performing ultraviolet-visible spectrum scanning on the sorbitol solution, the potassium salt solution and the mixed solution prepared in the step (2) and the sorbitol chelated potassium fertilizer precipitation solution obtained in the step (2) by using an ultraviolet-visible spectrophotometer within a wavelength range of 190 nm-230 nm to obtain detailed scanning maps of the solutions;

fourth, detection: and comparing and analyzing the scanning maps of the solutions by using the detailed scanning maps of the solutions obtained in the step three, eliminating the interference of alcohol by using the scanning map obtained by the sorbitol solution, eliminating the interference of potassium salt by using the scanning map of the potassium salt solution, comprehensively comparing the scanning maps of the solutions, and indirectly proving the generation of the new sorbitol chelated potassium substance by using the change of the maximum absorption peak.

Further, the volume ratio of the absolute ethyl alcohol to the acetone is 1:1-1: 2.

Compared with the prior art, the preparation method has the advantages of simple process, low energy consumption and good product quality, realizes the efficient utilization of potassium, and solves the problems of energy waste and non-point source pollution generated in the traditional agricultural production process from the source; the detection method can qualitatively prove the generation of the sorbitol chelated potassium, and fundamentally ensures that the research and development of the sugar alcohol chelated potassium related by the invention have significance.

The specific implementation mode is as follows:

the technical solution of the present invention is further illustrated by the following examples,

example 1:

the embodiment relates to a preparation method of a sorbitol chelated potassium fertilizer, which comprises the following specific steps:

(1) weighing: firstly, weighing 15 to 30 parts of sorbitol, 10 to 20 parts of deionized water (or softened water) and potassium salt according to the weight parts, wherein the potassium salt is 200 to 300 parts of potassium acetate for later use;

(2) dissolving: adding deionized water (or softened water) into a reaction kettle, setting the water bath temperature to be 50-90 ℃, heating at constant temperature, adding sorbitol into the reaction kettle after the temperature is stable, heating at constant temperature, continuously stirring until the sorbitol is completely dissolved into the deionized water (or softened water), and obtaining a mixed alcohol water solution, wherein the solution is in a clear and transparent state;

(3) mixing: the principle of adding all the raw materials is that after one component is fully stirred and completely dissolved, the next component is continuously added; adding potassium acetate into the mixed alcohol aqueous solution prepared in the step (2), keeping constant-temperature water bath heating, fully stirring until the solution is completely dissolved, and obtaining a mixed solution, wherein the solution is in a clear and transparent state;

(4) chelating: and (4) heating the mixed solution prepared in the step (3) in a constant-temperature water bath, stirring the mixed solution to perform chelation reaction, keeping the temperature of the water bath at 50-90 ℃, reacting for 0.5-1 h, taking out the reaction kettle after the reaction is finished, standing the reaction kettle, and cooling the reaction kettle to room temperature at room temperature to obtain the potassium sorbate chelated acetate fertilizer solution.

The embodiment also relates to a detection method of the prepared potassium sorbate chelating acetate fertilizer, which comprises the following steps:

preparing a detection solution: collecting the sorbitol chelated potassium acetate fertilizer solution for later use; respectively diluting sorbitol and potassium acetate used for preparing the sorbitol chelated potassium acetate fertilizer by 100 times with deionized water (or softened water) to prepare separate solutions for later use; preparing mixed solution of sorbitol and potassium acetate used for preparing sorbitol chelated potassium acetate, and then diluting 100 times with deionized water (or softened water) to prepare independent solution for later use;

treating the sorbitol chelated potassium acetate fertilizer solution: weighing 4g of a sorbitol chelated potassium acetate solution sample, adding the sorbitol chelated potassium acetate solution sample into a 50mL centrifuge tube, taking absolute ethyl alcohol and acetone as extracting agents, adding the extracting agents into the centrifuge tube, heating the centrifuge tube in a water bath at 60 ℃ for 30 minutes to fully dissolve the sorbitol chelated potassium acetate, standing the centrifuge tube at room temperature for 5 minutes, then centrifuging the centrifuge tube at a rotating speed of 6000 r/min for 20 minutes, pouring supernate in the centrifuge tube, continuously adding the extracting agents, continuously centrifuging the centrifuge tube at 6000 r/min for 20 minutes, repeating the operation for 3-5 times to completely dissolve reactants which are not chelated in the sorbitol chelated potassium acetate precipitate into supernate, collecting the supernate after the last centrifugation, using an ultraviolet-visible spectrophotometer to carry out colorimetry with the added extracting agents as a reference, and finishing the centrifugation when the reading of the ultraviolet-visible spectrophotometer is stable and close to zero, diluting the sorbitol chelated potassium acetate precipitate obtained after multiple centrifugations by 100 times with deionized water (or softened water) to prepare an independent solution for later use;

the volume ratio of the absolute ethyl alcohol to the acetone is 1: 2;

determination: performing ultraviolet-visible spectrum scanning on the sorbitol solution, the potassium acetate solution and the mixed solution prepared in the step (2) and the sorbitol chelated potassium acetate precipitation solution obtained in the step (2) within the wavelength range of 190 nm-230 nm respectively by using an ultraviolet-visible spectrophotometer to obtain detailed scanning maps of all solutions, wherein the maximum absorption peak of sorbitol appears at 193nm, the maximum absorption peak of potassium acetate appears at 203nm, the maximum absorption peak of the mixed solution appears at 208nm, and the maximum absorption peak of the sorbitol chelated potassium acetate solution appears at 216 nm;

fourth, detection: by utilizing detailed scanning maps of various solutions obtained in the step three and performing comparative analysis on the scanning maps and the maximum absorption peaks of the various solutions, firstly, the interference of the scanning map obtained by the sorbitol solution on alcohol is eliminated, then, the interference of potassium salt is eliminated through the scanning map of the potassium acetate solution, and the scanning maps of the solutions are comprehensively compared, so that the absorption peaks of the sorbitol chelated potassium acetate precipitation solution are obviously changed compared with other solutions, and the generation of a new substance of the sorbitol chelated potassium acetate is proved.

Example 2:

the embodiment relates to a preparation method of a sorbitol chelated potassium fertilizer, which comprises the following specific steps:

(1) weighing: firstly, weighing 15 to 30 parts of sorbitol, 10 to 20 parts of deionized water (or softened water) and 5 to 15 parts of potassium nitrate as potassium salt for later use;

(2) dissolving: the concrete procedure is the same as in (2) of example 1;

(3) mixing: the principle of adding all the raw materials is that after one component is fully stirred and completely dissolved, the next component is continuously added; then adding potassium nitrate into the mixed alcohol aqueous solution prepared in the step (2), keeping constant-temperature water bath heating, fully stirring until the potassium nitrate is completely dissolved, and after all the components are fully mixed, enabling the solution to be in a clear and transparent state to prepare a mixed solution of all the components;

(4) chelating: the concrete steps are the same as the step (4) of the embodiment 1, and the sorbitol chelated potassium nitrate fertilizer solution is prepared.

The embodiment also relates to a detection method of the prepared sorbitol chelated potassium nitrate fertilizer, which comprises the following specific steps:

preparing a detection solution: collecting the sorbitol chelated potassium nitrate fertilizer solution for later use; respectively diluting sorbitol and potassium nitrate used for preparing the sorbitol chelated potassium nitrate by 100 times with deionized water (or softened water) to prepare separate solutions for later use; preparing a mixed solution of sorbitol and potassium nitrate used for preparing the sorbitol chelated potassium nitrate, and then diluting the mixed solution by 100 times with deionized water (or softened water) to prepare a separate solution for later use;

treating the sorbitol chelated potassium nitrate solution: weighing 4g of sorbitol chelated potassium nitrate solution sample, adding the sorbitol chelated potassium nitrate solution sample into a 50mL centrifuge tube, taking absolute ethyl alcohol and acetone as extracting agents, adding the extracting agents into the centrifuge tube, heating the centrifuge tube in a water bath at 60 ℃ for 30 minutes to fully dissolve the sorbitol chelated potassium nitrate, standing the centrifuge tube at room temperature for 5 minutes, centrifuging the centrifuge tube at a rotating speed of 6000 revolutions per minute for 20 minutes, pouring supernate in the centrifuge tube, continuously adding the extracting agents, centrifuging the supernate for 20 minutes at 6000 revolutions per minute, repeating the operation for 3-5 times to fully dissolve reactants not chelated in the sorbitol chelated potassium nitrate precipitate into the supernate, collecting the supernate after the last centrifugation, carrying out color comparison by using an ultraviolet-visible spectrophotometer with the extracting agents as references, finishing the centrifugation when the reading of the ultraviolet-visible spectrophotometer is stable and is close to zero, diluting the sorbitol chelated potassium nitrate precipitate obtained after the repeated centrifugation by 100 times by using deionized water (or softened water) Preparing into single solution for later use;

the volume ratio of the absolute ethyl alcohol to the acetone is 1: 1.5;

determination: performing ultraviolet-visible spectrum scanning on the sorbitol solution, the potassium nitrate solution and the mixed solution prepared in the step (2) and the sorbitol chelated potassium nitrate precipitation solution obtained in the step (2) within the wavelength range of 190 nm-230 nm respectively by using an ultraviolet-visible spectrophotometer to obtain a detailed scanning map of each solution, wherein the maximum absorption peak of sorbitol appears at a position of 193nm, the maximum absorption peak of potassium nitrate appears at a position of 211nm, the maximum absorption peak of the mixed solution appears at a position of 214nm, and the maximum absorption peak of the sorbitol chelated potassium nitrate solution appears at a position of 217 nm;

fourth, detection: according to the detailed scanning maps of various solutions obtained in the step three, the scanning maps and the maximum absorption peaks of the various solutions are compared and analyzed, firstly, the interference of the scanning map obtained by the sorbitol solution on alcohol is eliminated, then, the interference of potassium salt is eliminated through the scanning map of the potassium nitrate solution, the scanning maps of the solutions are comprehensively compared, the maximum absorption peak of the sorbitol chelated potassium nitrate precipitation solution is found to be obviously changed compared with other solutions, and the generation of a new sorbitol chelated potassium nitrate substance is proved.

Example 3:

the embodiment relates to a preparation method of a sorbitol chelated potassium fertilizer, which comprises the following specific steps:

(1) weighing: firstly, weighing 15 to 30 parts of sorbitol, 10 to 20 parts of deionized water (or softened water) and potassium salt according to the weight parts, wherein the potassium salt is one of 5 to 15 parts of potassium chloride for later use;

(2) dissolving: the procedure was the same as in (2) of example 1;

(3) mixing: the principle of adding all the raw materials is that after one component is fully stirred and completely dissolved, the next component is continuously added; then adding potassium chloride into the mixed alcohol aqueous solution prepared in the step (2), keeping constant-temperature water bath heating, fully stirring until the components are completely dissolved, and after the components are fully mixed, enabling the solution to be in a clear and transparent state to prepare a mixed solution of the components;

(4) chelating: the concrete steps are the same as the step (4) of the embodiment 1, and the sorbitol chelated potassium chloride fertilizer solution is prepared.

The embodiment also relates to a detection method of the prepared sorbitol chelated potassium chloride fertilizer, which comprises the following specific steps:

preparing a detection solution: collecting the sorbitol chelated potassium chloride fertilizer solution for later use; respectively diluting 100 times of sorbitol and potassium chloride used for preparing sorbitol chelated potassium chloride with deionized water (or softened water) to prepare separate solutions for later use; preparing mixed solution of sorbitol and potassium chloride used for preparing sorbitol chelated potassium chloride, and then diluting 100 times with deionized water (or softened water) to prepare independent solution for later use;

treating a sorbitol chelated potassium chloride solution: weighing 4g of a sorbitol chelated potassium chloride solution sample, adding the sorbitol chelated potassium chloride solution sample into a 50mL centrifuge tube, taking absolute ethyl alcohol and acetone as extracting agents, adding the extracting agents into the centrifuge tube, heating the centrifuge tube in a water bath at 60 ℃ for 30 minutes to fully dissolve the sorbitol chelated potassium chloride, standing the centrifuge tube at room temperature for 5 minutes, centrifuging the centrifuge tube at a rotating speed of 6000 r/min for 20 minutes, pouring supernate in the centrifuge tube, continuously adding the extracting agents, centrifuging the supernate for 20 minutes at 6000 r/min, repeating the operation for 3-5 times to fully dissolve reactants not chelated in the sorbitol chelated potassium chloride precipitate into supernate, collecting the supernate after the last centrifugation, carrying out color comparison by using an ultraviolet-visible spectrophotometer with the extracting agents as references, finishing the centrifugation when the reading of the ultraviolet-visible spectrophotometer is stable and close to zero, diluting the sorbitol chelated potassium chloride precipitate obtained after multiple centrifugations by 100 times with deionized water (or softened water) to prepare an independent solution for later use;

the volume ratio of the absolute ethyl alcohol to the acetone is 1: 1;

determination: performing ultraviolet-visible spectrum scanning on the sorbitol solution, the potassium chloride solution and the mixed solution prepared in the step (2) and the sorbitol chelated potassium chloride precipitation solution obtained in the step (2) within the wavelength range of 190 nm-230 nm respectively by using an ultraviolet-visible spectrophotometer to obtain detailed scanning maps of all solutions, wherein the maximum absorption peak of sorbitol appears at 193nm, the maximum absorption peak of potassium chloride appears at 202nm, the maximum absorption peak of the mixed solution appears at 206nm, and the maximum absorption peak of the sorbitol chelated potassium chloride solution appears at 213 nm;

fourth, detection: by utilizing detailed scanning maps of various solutions obtained in the step three and performing comparative analysis on the scanning maps and the maximum absorption peaks of the various solutions, firstly, the interference of the scanning map obtained by the sorbitol solution on alcohol is eliminated, then, the interference of potassium salt is eliminated through the scanning map of the potassium chloride solution, and the scanning maps of the solutions are comprehensively compared, so that the phenomenon that the maximum absorption peak of the sorbitol chelated potassium chloride precipitation solution is obviously shifted to the right compared with other solutions can be found, and the generation of a new substance of the sorbitol chelated potassium chloride is proved.

Example 4:

this example relates to a method for qualitative analytical detection of various solutions prepared in examples 1, 2, and 3 based on optical rotation; the chelating reaction proceeds to change the structure of the optically active sorbitol, and thus the optical activity of the solution thereof also changes, and specific changes of the optical activities of the respective substances in the above examples are shown in table 1.

TABLE 1 results of measurement of optical rotation of each substance

	Example 1	Example 2	Example 3
				Sorbitol	-0.3°	-0.9°	-1.3°
Potassium salt	0°	0°	0°
				Sorbitol mixed potassium solution	1.05°	0.5°	0.4°
Potassium sorbitol chelate solution	0.8°	0.1°	0.15°

And (4) conclusion: as can be seen from Table 1, the optical rotation of the potassium sorbitol chelate solution in each example is different from that of the potassium sorbitol and sorbitol mixed solution, which indicates that the sorbitol in the solution is structurally changed to generate a new substance of potassium sorbitol chelate; the method for detecting the generation of the potassium sorbate chelate by the optical rotation method has higher accuracy and repeatability, and the result is consistent with the detection result of the ultraviolet-visible spectrophotometry in the technical scheme, so that the accuracy of the ultraviolet-visible spectrophotometry is verified.