Method for determining the platinum content of a platinum dinitrosodiiminate

Abstract

The application relates to a method for measuring the platinum content in disodium platinum, which comprises the following steps: firstly mixing disodium platinum and acid liquid, adding a nitrogen removal agent after adjusting the pH value for second mixing, third mixing with a platinum coordination agent after heating concentration and dilution, adding a reducing agent for reduction reaction, obtaining platinum precipitation after solid-liquid separation; ashing the platinum precipitation and filter paper, calcining and cooling to constant weight, weighing the net mass of platinum, and calculating the platinum content in disodium platinum by using formula I. The application has accurate measurement results, the allowable difference is controlled within 0.20%, and the relative standard deviation is controlled within 0.16%. The method eliminates the platinum mirror phenomenon in the reduction process and improves the reduction efficiency, avoids the interference of nitroso and amino groups on the platinum content measurement in the traditional potassium permanganate current titration method, reduces the complex operation steps, and solves the problem that the measurement error of the platinum content in disodium platinum is relatively large in the potassium permanganate current titration method.

Description

Technical Field

[0001] This invention relates to the field of metal content testing technology, and in particular to a method for determining the platinum content in dinitrosodiamineplatinum. Background Technology

[0002] Due to platinum's unique outer electron shell structure, platinum compounds are widely used in petrochemicals, electroplating, green catalysis, and jewelry. Especially in the electroplating industry, dinitrosodiamineplatinum solution is primarily used for platinum plating in cyanide-free electroplating. To ensure stable and consistent quality in industrial use, accurate measurement of the platinum content percentage is necessary.

[0003] Currently, the main methods for detecting platinum content in platinum compounds include potassium permanganate electrotitration (YS / T646.1-2017), ammonium chloride precipitation, and hydrogen reduction ICP. While potassium permanganate electrotitration can accurately determine the titration endpoint based on current jumps, it is cumbersome, requiring complex steps such as high-temperature calcination, reduction and dissolution, preparation of oxidizing and reducing solutions, gas blowing, standard solution preparation, and sample calibration. When the platinum content exceeds 60%, the allowable difference can reach 0.35%, often failing to meet accuracy requirements. Furthermore, the titration method is typically subject to significant human error. Ammonium chloride precipitation carries the risk of platinum loss during operation, particularly in the ammonium chloride precipitate filtrate, leading to poor parallelism in platinum content testing. For example, CN119269614A discloses a hydrogen reduction ICP method for platinum content determination. Although it has high analytical efficiency, the stability of the ICP analysis is poor when the platinum content in the solution exceeds 5%, and the dilution process of the platinum solution can easily amplify the error.

[0004] Especially for the determination of platinum content in the compound dinitrosodiamineplatinum (Pt(NH3)2(NO2)2), the potassium permanganate electrotitration method is commonly used in the field. However, the nitroso and amino groups in its structure can cause significant interference to the platinum content measurement, resulting in large measurement errors. Due to the presence of nitroso and amino groups, the gravimetric method is rarely used in the field for the determination of platinum content. The strong coordination of nitroso and amino groups makes it difficult to be completely reduced by hydrazine hydrate, sodium borohydride, etc. In addition, the reduction reaction is slow and a large amount of platinum mirror is generated during the reduction process, which also affects the accuracy of the gravimetric method and leads to high measurement errors.

[0005] Therefore, how to provide a simple, efficient, and accurate method for determining the platinum content in dinitrosodiamineplatin has become an urgent technical problem to be solved. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides a method for determining the platinum content in dinitrosodiammineplatin. The method introduces a denitrifying agent during the determination process to remove coordination interference from nitrosyl and amino groups in dinitrosodiammineplatin. Simultaneously, a platinum coordinating agent is introduced to form a more active platinum compound, completely avoiding the formation of a platinum mirror, resulting in a more complete reduction process, improved reduction efficiency, and easier collection. In the post-treatment of the platinum precipitate, ashing and calcination further ensure the accuracy of the platinum content determination in dinitrosodiammineplatin. The entire method of this invention is simple and efficient to operate, yields accurate results, with an allowable error controlled within 0.20% and a relative standard deviation controlled within 0.16%, making it of great application value.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides a method for determining the platinum content in dinitrosodiamineplatinum, the method comprising the following steps:

[0009] S1. The first mixture is prepared by mixing dinitrosodiammineplatin and acid solution, and the pH is adjusted to obtain the first mixture.

[0010] S2. The denitrifying agent and the first mixture from step S1 are mixed a second time, and then concentrated and diluted by heating to obtain a platinum compound solution;

[0011] S3. Mix the platinum ligand and the platinum compound solution described in step S2 in a third mixing, then add a reducing agent to carry out a reduction reaction until the reaction solution is clear. After solid-liquid separation, a platinum precipitate is obtained.

[0012] S4. After the platinum precipitate and filter paper described in step S3 are ashed, they are calcined and cooled to constant weight. The net weight of platinum is weighed, and the platinum content in the dinitrosodiamineplatinum is calculated using formula I.

[0013] ω = m1 / m0 × 100%, Formula I; where ω is the platinum content in dinitrosodiamineplatin; m1 is the net mass of platinum; and m0 is the mass of dinitrosodiamineplatin.

[0014] The determination method provided by this invention avoids the interference of nitrosyl and amino groups on the determination of platinum content in the potassium permanganate electrotitration method, and reduces the complex operation steps in the potassium permanganate electrotitration method, such as reduction and dissolution, preparation of oxidizing solution, preparation of reducing solution, gas blowing treatment, preparation of standard solution, and sample calibration. It solves the problem of large measurement error of dinitrosodiammineplatin in the commonly used potassium permanganate electrotitration method. The determination method of this invention introduces a denitrifying agent during the determination process to remove the coordination interference of nitrosyl and amino groups in dinitrosodiammineplatin. At the same time, a platinum complexing agent is introduced to form a platinum compound with higher activity, completely avoiding the formation of platinum mirror, making the reduction process more complete, improving the reduction efficiency and making it easier to collect. In the post-treatment of platinum precipitation, ashing and calcination treatments further ensure the accuracy of the determination of platinum content in dinitrosodiammineplatin. The entire determination method is simple and efficient to operate, and the determination results are accurate, with the allowable difference controlled within 0.20% and the relative standard deviation controlled within 0.16%, which has great application value.

[0015] As a preferred technical solution of the present invention, the acid in the acid solution in step S1 includes any one or a combination of at least two of nitric acid, sulfuric acid or hydrochloric acid.

[0016] In the acid solution of the present invention, the acid includes nitric acid, sulfuric acid or hydrochloric acid, wherein the nitric acid is concentrated nitric acid, the sulfuric acid is concentrated sulfuric acid, and the hydrochloric acid is concentrated hydrochloric acid. These are all mass fractions and densities conventionally used in the art. Therefore, the present invention does not impose specific requirements or special limitations on their respective mass fractions and densities, as long as they are concentrated nitric acid, concentrated sulfuric acid and concentrated hydrochloric acid.

[0017] Preferably, the mass ratio of acid to pure water in the acid solution in step S1 is (0.1~0.5):1, for example, 0.1:1, 0.15:1, 0.2:1, 0.25:1, 0.3:1, 0.35:1, 0.4:1, 0.45:1 or 0.5:1, etc.

[0018] Preferably, in step S1, the mass ratio of the dinitrosodiamineplatinum to the acid solution is (0.1~0.5):1, for example, 0.1:1, 0.15:1, 0.2:1, 0.25:1, 0.3:1, 0.35:1, 0.4:1, 0.45:1 or 0.5:1, etc.

[0019] As a preferred technical solution of the present invention, the first mixing in step S1 is heating and dissolving.

[0020] Preferably, the temperature of the first mixing in step S1 is 70℃~100℃, such as 70℃, 75℃, 80℃, 85℃, 90℃, 95℃ or 100℃.

[0021] As a preferred embodiment of the present invention, the pH adjuster used in step S1 for adjusting the pH includes sodium hydroxide. Preferably, the pH of the first mixture in step S1 is 4 to 9, such as 4, 5, 6, 7, 8, or 9.

[0022] As a preferred technical solution of the present invention, the nitrogen removal agent in step S2 includes any one or a combination of at least two of hydrochloric acid, sulfuric acid or aminosulfonic acid.

[0023] In the nitrogen removal agent of this invention, the hydrochloric acid is concentrated hydrochloric acid and the sulfuric acid is concentrated sulfuric acid, both of which are conventionally used in the art in terms of mass fraction and density. Therefore, this invention does not impose specific requirements or special limitations on their respective mass fractions and densities, as long as they are concentrated hydrochloric acid and concentrated sulfuric acid.

[0024] Preferably, the mass ratio of the denitrifying agent in step S2 to the dinitrosodiamineplatinum in step S1 is (1~10):1, for example, 1:1, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1 or 10:1, etc.

[0025] In this invention, controlling the mass ratio of the denitrifying agent to dinitrosodiamineplatinum to be (1~10):1 ensures good parallelism and accuracy of the platinum content test results. If the amount of denitrifying agent added is too small, it will result in a large amount of residual nitrosyl and amino groups, preventing complete reduction of the platinum compounds, leading to poor test parallelism and lower platinum content results. Conversely, if the amount of denitrifying agent added is too large, it will result in excessive salt content in the solution, leading to excessive ion residue in the reduced platinum powder, resulting in poor test parallelism and higher platinum content results.

[0026] As a preferred technical solution of the present invention, the heating and concentration temperature in step S2 is 70℃~100℃, for example 70℃, 75℃, 80℃, 85℃, 90℃, 95℃ or 100℃.

[0027] Preferably, the platinum ion concentration in the resulting concentrate obtained by heating and concentrating in step S2 is 10wt%~50wt%, for example, 10wt%, 15wt%, 20wt%, 25wt%, 30wt%, 35wt%, 40wt%, 45wt%, or 50wt%.

[0028] Preferably, the platinum ion concentration in the platinum compound solution in step S2 is 1wt% to 5wt%, for example, 1wt%, 1.5wt%, 2wt%, 2.5wt%, 3wt%, 3.5wt%, 4wt%, 4.5wt%, or 5wt%.

[0029] As a preferred technical solution of the present invention, the platinum coordination agent in step S3 includes ammonium chloride and / or potassium chloride.

[0030] Preferably, the mass ratio of the platinum ligand in step S3 to the dinitrosodiamineplatinum in step S1 is (1~10):1, for example, 1:1, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1 or 10:1.

[0031] In this invention, controlling the mass ratio of platinum ligand to dinitrosodiamineplatinum to be (1~10):1 ensures good parallelism and accuracy of platinum content test results. If the amount of platinum ligand added is too small, the reducing activity of platinum compounds in the solution decreases, resulting in a slight platinum mirror phenomenon and loss during platinum transfer, leading to poor test parallelism and lower platinum content results. Conversely, if the amount of platinum ligand added is too large, the salt content in the solution becomes too high, resulting in excessive ion residue in the reduced platinum powder, leading to poor test parallelism and higher platinum content results.

[0032] Preferably, the temperature of the third mixing in step S3 is 70℃~100℃, such as 70℃, 75℃, 80℃, 85℃, 90℃, 95℃ or 100℃.

[0033] Preferably, step S3 involves the third mixing process until the mixed solution boils.

[0034] As a preferred technical solution of the present invention, the reducing agent in step S3 includes any one or a combination of at least two of formic acid, hydrazine hydrate or sodium borohydride.

[0035] In this invention, there are no specific requirements or special limitations on the amount of reducing agent added, as long as the reaction solution is clear. Those skilled in the art can make adaptive selections and adjustments according to actual conditions.

[0036] Preferably, the temperature of the reduction reaction in step S3 is 70℃~100℃, such as 70℃, 75℃, 80℃, 85℃, 90℃, 95℃ or 100℃.

[0037] Preferably, the reduction reaction time in step S3 is 0.2h to 2h, for example, 0.2h, 0.5h, 0.8h, 1h, 1.2h, 1.5h, 1.8h or 2h.

[0038] Preferably, after the reduction reaction in step S3 ends and before the solid-liquid separation, a settling step is also included.

[0039] Preferably, the settling time is 0.5h to 2h, for example, 0.5h, 0.8h, 1h, 1.2h, 1.5h, 1.8h or 2h.

[0040] Preferably, the solid-liquid separation in step S3 includes filtration.

[0041] It should be noted that the present invention does not impose specific requirements or special limitations on the filter paper used for filtration, and commonly used filter papers in the art are applicable to the present invention.

[0042] As a preferred technical solution of the present invention, the ashing temperature in step S4 is 100℃~250℃, such as 100℃, 120℃, 150℃, 180℃, 200℃, 220℃ or 250℃.

[0043] Preferably, the ashing time in step S4 is 0.2h to 2h, for example, 0.2h, 0.5h, 0.8h, 1h, 1.2h, 1.5h, 1.8h or 2h.

[0044] As a preferred technical solution of the present invention, the calcination holding temperature in step S4 is 500℃~850℃, for example 500℃, 550℃, 600℃, 650℃, 700℃, 750℃, 800℃ or 850℃, etc.

[0045] Preferably, the holding time for calcination in step S4 is 0.2h to 2h, for example, 0.2h, 0.5h, 0.8h, 1h, 1.2h, 1.5h, 1.8h or 2h.

[0046] As a preferred technical solution of the present invention, the determination method includes the following steps:

[0047] S1. The dinitrosodiamineplatinum and acid solution are mixed in a mass ratio of (0.1~0.5):1. The temperature of the first mixing is 70℃~100℃. After adjusting the pH, a first mixture with a pH of 4~9 is obtained.

[0048] The mass ratio of acid to pure water in the acid solution is (0.1~0.5):1;

[0049] S2. Mix the denitrifying agent and the first mixture from step S1 in a second mixing process, heat and concentrate the mixture at 70°C to 100°C until the concentration of platinum ions in the concentrate is 10wt% to 50wt%, and then dilute it to obtain a platinum compound solution with a platinum ion concentration of 1wt% to 5wt%.

[0050] The mass ratio of the nitrogen remover to the dinitrosodiaminoplatinum in step S1 is (1~10):1;

[0051] S3. The platinum ligand and the platinum compound solution described in step S2 are mixed for the third time at a temperature of 70℃~100℃. The third mixing is stopped when the solution boils. Then, a reducing agent is added and the reduction reaction is carried out at 70℃~100℃ for 0.2h~2h until the reaction solution becomes clear. The reduction reaction is stopped and the solution is allowed to stand for 0.5h~2h. After solid-liquid separation, platinum precipitate is obtained.

[0052] The mass ratio of the platinum ligand to the dinitrosodiamineplatinum in step S1 is (1~10):1;

[0053] S4. After ashing the platinum precipitate and filter paper described in step S3 at 100℃~250℃ for 0.2h~2h, calcine them at 500℃~850℃ for 0.2h~2h, cool them to constant weight, weigh the net weight of platinum, and calculate the platinum content in the dinitrosodiamineplatinum using Formula I.

[0054] ω = m1 / m0 × 100%, Formula I; where ω is the platinum content in dinitrosodiamineplatin; m1 is the net mass of platinum; and m0 is the mass of dinitrosodiamineplatin.

[0055] Compared with the prior art, the present invention has at least the following beneficial effects:

[0056] 1) The determination method provided by this invention avoids the interference of nitrosamines and amino groups on the determination of platinum content in the potassium permanganate electrotitration method, and reduces the complex operation steps in the potassium permanganate electrotitration method, such as reduction and dissolution, preparation of oxidizing solution, preparation of reducing solution, gas blowing treatment, preparation of standard solution, and sample calibration. It solves the problem of large measurement error of dinitrosamine diammonium platinum in the commonly used potassium permanganate electrotitration method. The entire determination method is simple and efficient to operate, and the determination results are accurate. The allowable difference is controlled within 0.20%, and the relative standard deviation is controlled within 0.16%, which has great application value.

[0057] 2) The method of this invention introduces a denitrifying agent during the determination process to remove the coordination interference of nitrosodiamineplatin and amino groups. At the same time, a platinum coordination agent is introduced to form a platinum compound with higher activity, which completely avoids the formation of platinum mirror, making the reduction process more complete, improving the reduction efficiency and making it easier to collect. In the post-treatment of platinum precipitate, ashing and calcination are carried out to further ensure the accuracy of the determination of platinum content in dinitrosodiamineplatin. Detailed Implementation

[0058] To facilitate understanding of the present invention, the following embodiments are provided. Those skilled in the art should understand that these embodiments are merely illustrative and should not be construed as limiting the scope of the invention.

[0059] Unless otherwise stated, the raw materials and reagents used in the following examples are commercially available products or can be prepared by known methods.

[0060] The same dinitrosodiamineplatinum material is used in all the specific embodiments of this invention.

[0061] Example 1

[0062] This embodiment provides a method for determining the platinum content in dinitrosodiamineplatinum, the method comprising the following steps:

[0063] S1. Weigh 0.5g of dinitrosodiammineplatinum (solid), add 3mL of concentrated nitric acid and 9mL of pure water, heat at 70℃ until the solid dissolves (first mixture), add sodium hydroxide to adjust the pH of the solution, and obtain the first mixture with a pH of 7;

[0064] S2. Add 4g of aminosulfonic acid to the first mixture (the second mixture, in which the mass ratio of aminosulfonic acid and dinitrosodiamineplatinum is 8:1), and then heat at 90°C to remove ammonia and concentrate until the concentration of platinum ions in the resulting concentrate is 13wt%. After diluting with pure water, a platinum compound solution with a platinum ion concentration of 1wt% is obtained.

[0065] S3. Add 3g of potassium chloride to a platinum compound solution (the mass ratio of potassium chloride to dinitrosodiammonium platinum is 6:1), heat at 90℃ until the mixed solution is slightly boiling (third mixing), add 8mL of hydrazine hydrate to carry out the reduction reaction, keep heating at 90℃ for 1h, the reaction solution is clear and colorless, let stand for 1h, filter and wash to obtain platinum precipitate.

[0066] S4. After ashing the platinum precipitate and filter paper at 200℃ for 1 hour, place them in a muffle furnace and calcine at 650℃ for 2 hours. After cooling to constant weight, weigh the net mass of platinum and calculate the platinum content in dinitrosodiamineplatinum using ω=m1 / m0×100%.

[0067] Example 2

[0068] This embodiment provides a method for determining the platinum content in dinitrosodiamineplatinum, the method comprising the following steps:

[0069] S1. Weigh 0.5g of dinitrosodiammineplatinum solid, add 3mL of concentrated nitric acid, 1mL of concentrated hydrochloric acid, and 20mL of pure water, and heat at 90℃ until the solid dissolves (first mixture). Add sodium hydroxide to adjust the pH of the solution to obtain the first mixture with a pH of 5.

[0070] S2. Add 3g of aminosulfonic acid and 1mL of concentrated hydrochloric acid to the first mixture (the second mixture, in which the mass ratio of aminosulfonic acid, concentrated hydrochloric acid and dinitrosodiamineplatinum is 8.36:1), and then heat at 100℃ to remove ammonia and concentrate until the concentration of platinum ions in the resulting concentrate is 17wt%. After diluting with pure water, a platinum compound solution with a platinum ion concentration of 1.5wt% is obtained.

[0071] S3. Add 3g of ammonium chloride to a platinum compound solution (the mass ratio of ammonium chloride to dinitrosodiamineplatinum is 6:1), heat at 90℃ until the mixed solution is slightly boiling (third mixing), add 5mL of hydrazine hydrate to carry out the reduction reaction, keep heating at 90℃ for 2h, the reaction solution is clear and colorless, let stand for 0.5h, filter and wash to obtain platinum precipitate;

[0072] S4. After ashing the platinum precipitate and filter paper at 250℃ for 0.5h, calcine them in a muffle furnace at 750℃ for 2h, cool them to constant weight, weigh the net weight of platinum, and calculate the platinum content in dinitrosodiamineplatinum using ω=m1 / m0×100%.

[0073] Example 3

[0074] This embodiment provides a method for determining the platinum content in dinitrosodiamineplatinum, the method comprising the following steps:

[0075] S1. Weigh 0.5g of dinitrosodiammineplatinum solid, add 3mL of concentrated nitric acid, 1mL of concentrated sulfuric acid, and 30mL of pure water, and heat at 100℃ until the solid dissolves (first mixture). Add sodium hydroxide to adjust the pH of the solution to obtain the first mixture with a pH of 8.

[0076] S2. Add 4g of aminosulfonic acid to the first mixture (the second mixture has an aminosulfonic acid and dinitrosodiamineplatinum mass ratio of 8:1), then heat at 100℃ to remove ammonia and concentrate until the platinum ion concentration in the resulting concentrate is 26wt%. After diluting with pure water, a platinum compound solution with a platinum ion concentration of 3wt% is obtained.

[0077] S3. Add 3g of potassium chloride to a platinum compound solution (the mass ratio of potassium chloride to dinitrosodiammonium platinum is 6:1), heat at 100℃ until the mixed solution is slightly boiling (third mixing), add 3mL of hydrazine hydrate to carry out the reduction reaction, keep heating at 100℃ for 1h, the reaction solution is clear and colorless, let stand for 2h, filter and wash to obtain platinum precipitate.

[0078] S4. After ashing the platinum precipitate and filter paper at 200℃ for 2 hours, place them in a muffle furnace and calcine at 850℃ for 1 hour. Cool to constant weight, weigh the net mass of platinum, and calculate the platinum content in dinitrosodiamineplatinum using ω=m1 / m0×100%.

[0079] Example 4

[0080] This embodiment provides a method for determining the platinum content in dinitrosodiamineplatin. The difference between this method and that in Example 2 is that the denitrifying agent in step S2 is replaced by equal amounts of aminosulfonic acid and concentrated hydrochloric acid with aminosulfonic acid and concentrated sulfuric acid. The mass ratio of aminosulfonic acid, concentrated sulfuric acid and dinitrosodiamineplatin is 9.68:1. The remaining determination methods and parameters are consistent with those in Example 2.

[0081] Example 5

[0082] This embodiment provides a method for determining the platinum content in dinitrosodiamineplatin. The difference between this method and that in Example 1 is that the reducing agent in step S2 is replaced by formic acid instead of hydrazine hydrate. The remaining determination methods and parameters are consistent with those in Example 1.

[0083] Example 6

[0084] This embodiment provides a method for determining the platinum content in dinitrosodiamineplatin. The difference between this method and that in Example 1 is that the mass ratio of the denitrifying agent aminosulfonic acid to dinitrosodiamineplatin in step S2 is 0.8:1. The remaining determination methods and parameters are consistent with those in Example 1.

[0085] Example 7

[0086] This embodiment provides a method for determining the platinum content in dinitrosodiamineplatin. The difference between this method and that in Example 1 is that the mass ratio of the platinum ligand potassium chloride to dinitrosodiamineplatin in step S3 is 0.5:1, while the remaining determination methods and parameters are consistent with those in Example 1.

[0087] Example 8

[0088] This embodiment provides a method for determining the platinum content in dinitrosodiamineplatin. The difference between this method and that in Example 1 is that the mass ratio of the denitrifying agent aminosulfonic acid to dinitrosodiamineplatin in step S2 is 11:1. The remaining determination methods and parameters are consistent with those in Example 1.

[0089] Example 9

[0090] This embodiment provides a method for determining the platinum content in dinitrosodiamineplatin. The difference between this method and that in Example 1 is that the mass ratio of the platinum ligand potassium chloride to dinitrosodiamineplatin in step S3 is 11:1, while the remaining determination methods and parameters are consistent with those in Example 1.

[0091] Comparative Example 1

[0092] This comparative example provides a method for determining the platinum content in dinitrosodiamineplatin. The difference between this method and Example 1 is that the addition of the nitrogen-removing agent aminosulfonic acid is omitted. After the first mixing in step S1 is completed, step S3 is directly performed, in which 3g of potassium chloride is added to the first mixture. The remaining determination methods and parameters are consistent with those in Example 1.

[0093] Comparative Example 2

[0094] This comparative example provides a method for determining the platinum content in dinitrosodiamineplatin. The difference between this method and Example 1 is that the addition of potassium chloride as a coordinating agent is omitted. After obtaining a platinum compound solution with a platinum ion concentration of 1 wt% in step S2, the solution is directly heated to 90°C until it just boils, and 8 mL of hydrazine hydrate is added to carry out a reduction reaction. The remaining determination methods and parameters are consistent with those in Example 1.

[0095] Comparative Example 3

[0096] This comparative example provides a method for determining the platinum content in dinitrosodiamineplatin. The difference between this method and Example 1 is that step S4, platinum precipitation and filter paper ashing, is omitted. The remaining determination methods and parameters are consistent with those of Example 1.

[0097] Comparative Example 4

[0098] This comparative example provides a method for determining the platinum content in dinitrosodiammineplatinum. The difference between this method and Example 1 is that step S4, calcination in a muffle furnace, is omitted. The remaining determination methods and parameters are consistent with those of Example 1.

[0099] Comparative Example 5

[0100] This comparative example provides a method for determining the platinum content in dinitrosodiamineplatin. The determination method adopts the traditional potassium permanganate electrotitration method, and the determination method is carried out in accordance with the industry standard YS / T646.1-2017 "Chemical Analysis Methods for Platinum Compounds - Part 1: Determination of Platinum Content - Potassium Permanganate Electrotitration Method".

[0101] The platinum content determination results of dinitrosodiammineplatin in Examples 1-9 and Comparative Examples 1-5 are shown in Table 1. The industry standard YS / T596-2022 specifies that the platinum content in the tested product dinitrosodiammineplatin is 59.5%~60.8%.

[0102] Table 1

[0103]

[0104] The test results show that:

[0105] (1) As can be seen from Examples 1 to 5, the present invention removes the coordination interference of nitrosodiamineplatin and amino groups in dinitrosodiamineplatin by introducing a denitrifying agent during the determination process. At the same time, a platinum coordination agent is introduced to form a platinum compound with higher activity, which completely avoids the formation of platinum mirror, making the reduction process more complete, improving the reduction efficiency and making it easier to collect. In the post-treatment of platinum precipitate, the ashing and calcination treatment further ensures the accuracy of the determination of platinum content in dinitrosodiamineplatin. The allowable difference is controlled within 0.20%, and the relative standard deviation is controlled within 0.16%, which has great application value.

[0106] (2) As can be seen from Examples 1, 6 and 8, by further adjusting the mass ratio of the denitrifying agent and dinitrosodiamineplatin to (1~10):1, the present invention can ensure that the platinum content test results have good parallelism and accuracy. As can be seen from Examples 1, 7 and 9, by further adjusting the mass ratio of the platinum coordination agent and dinitrosodiamineplatin to (1~10):1, the present invention can ensure that the platinum content test results have good parallelism and accuracy.

[0107] (3) As can be seen from Example 1 and Comparative Examples 1-2, in Comparative Example 1, the omission of the denitrifying agent will result in most of the platinum compounds not being completely reduced; in Comparative Example 2, the omission of the platinum coordinating agent will result in the obvious platinum mirror phenomenon, and the platinum content cannot be accurately determined. As can be seen from Example 1 and Comparative Examples 3-4, in Comparative Example 3, the platinum precipitate and filter paper are not ashed and are directly calcined, which will lead to serious material volatilization, resulting in poor parallelism of platinum content and low results. In Comparative Example 4, if the platinum precipitate is not calcined in a muffle furnace, the residue after ashing will not be removed, resulting in poor parallelism of platinum content and high results. As can be seen from Examples 1-5 and Comparative Example 5, the test allowable error and relative standard deviation are too high when using the traditional potassium permanganate current titration method to determine the platinum content in dinitrosodiamineplatinum.

[0108] In summary, the method of this invention introduces a denitrifying agent during the determination process to remove the coordination interference of nitrosodiamineplatin and amino groups. Simultaneously, a platinum coordinating agent is introduced to form a more active platinum compound, completely avoiding the formation of a platinum mirror. This results in a more complete reduction process, improved reduction efficiency, and easier collection. Furthermore, the post-treatment of the platinum precipitate, through ashing and calcination, further ensures the accuracy of the platinum content determination in dinitrosodiamineplatin. The entire method of this invention is simple and efficient to operate, yields accurate results, with an allowable error controlled within 0.20% and a relative standard deviation controlled within 0.16%, demonstrating significant application value.

[0109] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A method for determining the platinum content in dinitrosodiammineplatinum, characterized in that, The determination method includes the following steps: S1. Mix dinitrosodiammineplatinum and acid solution in the first mixture, and adjust the pH to 4-9 to obtain the first mixture. S2. The nitrogen remover and the first mixture from step S1 are mixed for the second time, and then concentrated and diluted by heating to obtain a platinum compound solution. The nitrogen remover includes any one or a combination of at least two of hydrochloric acid, sulfuric acid, and aminosulfonic acid. S3. Mix the platinum ligand and the platinum compound solution from step S2 in a third mixing, then add a reducing agent to carry out a reduction reaction until the reaction solution is clear. After solid-liquid separation, a platinum precipitate is obtained. The platinum ligand includes ammonium chloride and / or potassium chloride, and the reducing agent includes any one or a combination of at least two of formic acid, hydrazine hydrate, and sodium borohydride. S4. After the platinum precipitate and filter paper described in step S3 are ashed, they are calcined and cooled to constant weight. The net weight of platinum is weighed, and the platinum content in the dinitrosodiamineplatinum is calculated using formula I. ω = m1 / m0 × 100%, Formula I; where ω is the platinum content in dinitrosodiamineplatin; m1 is the net mass of platinum; and m0 is the mass of dinitrosodiamineplatin.

2. The determination method according to claim 1, characterized in that, The acid in the acid solution described in step S1 includes any one or a combination of at least two of nitric acid, sulfuric acid, and hydrochloric acid.

3. The determination method according to claim 1, characterized in that, The mass ratio of acid to pure water in the acid solution described in step S1 is (0.1~0.5):

1.

4. The determination method according to claim 1, characterized in that, In step S1, the mass ratio of the dinitrosodiammineplatinum to the acid solution is (0.1~0.5):

1.

5. The determination method according to claim 1, characterized in that, Step S1: The first mixing is achieved by heating and dissolving.

6. The determination method according to claim 5, characterized in that, The heating and melting temperature is 70℃~100℃.

7. The determination method according to claim 1, characterized in that, The pH adjuster used in step S1 to adjust the pH includes sodium hydroxide.

8. The determination method according to claim 1, characterized in that, The mass ratio of the denitrifying agent in step S2 to the dinitrosodiamineplatinum in step S1 is (1~10):

1.

9. The determination method according to claim 1, characterized in that, The heating and concentration temperature in step S2 is 70℃~100℃.

10. The determination method according to claim 1, characterized in that, In step S2, the concentration of platinum ions in the resulting concentrate is 10wt%~50wt% after heating and concentration.

11. The determination method according to claim 1, characterized in that, The platinum ion concentration in the platinum compound solution described in step S2 is 1wt%~5wt%.

12. The determination method according to claim 1, characterized in that, The mass ratio of the platinum ligand in step S3 to the dinitrosodiamineplatinum in step S1 is (1~10):

1.

13. The determination method according to claim 1, characterized in that, The temperature of the third mixing step S3 is 70℃~100℃.

14. The determination method according to claim 1, characterized in that, Step S3, the third mixing, continues until the mixed solution boils.

15. The determination method according to claim 1, characterized in that, The temperature of the reduction reaction in step S3 is 70℃~100℃.

16. The determination method according to claim 1, characterized in that, The reduction reaction in step S3 takes 0.2 h to 2 h.

17. The determination method according to claim 1, characterized in that, After the reduction reaction in step S3 is completed and before the solid-liquid separation, a settling step is also included.

18. The determination method according to claim 17, characterized in that, The settling time is 0.5h to 2h.

19. The determination method according to claim 1, characterized in that, The ashing temperature in step S4 is 100℃~250℃.

20. The determination method according to claim 1, characterized in that, The ashing time in step S4 is 0.2h to 2h.

21. The determination method according to claim 1, characterized in that, The holding temperature for calcination in step S4 is 500℃~850℃.

22. The determination method according to claim 1, characterized in that, The holding time for calcination in step S4 is 0.2h to 2h.

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