A rapid detection method for sodium polydisulfide dipropane sulfonate

Abstract

The present invention discloses a rapid detection method for sodium polydisulfide (PDPS). The method comprises preparing a buffer solution and an Elma color developer; preparing multiple sets of sodium polydisulfide (PDPS) solutions of different concentrations; pretreating the sodium polydisulfide (PDPS) solutions with an excess of a boron hydride compound as a reducing agent to reduce the sodium polydisulfide to a thiol-containing compound; and removing the excess reducing agent. An absorbance test is performed to establish a standard curve for the concentration and absorbance of the brightener, and the concentration of the sodium polydisulfide (PDPS) in the electrolyte to be tested is measured using the established standard curve. The method uses a boron hydride compound as a reducing agent and utilizes ultraviolet-visible spectroscopy to rapidly detect the content of the brightener, sodium polydisulfide (PDPS). The method is convenient and simple to operate, provides highly accurate test data, and is applicable to the detection of electroplating bath additives in various systems.

Description

Technical Field

[0001] The present invention relates to the technical field of chemical detection, and in particular to a rapid detection method for sodium polydisulfide dipropane sulfonate. Background Art

[0002] In recent years, with the rapid development of new energy and high-end electronics manufacturing, the demand for high-performance electronic electroplating products has become increasingly stringent, and research has garnered increasing attention, particularly on the relationship between different additives in printed circuit board (PCB) electrolytes and the Cu electrodeposition process and product performance. Common additives include chloride ions, polyethylene glycol, amine-containing inhibitors, and sulfur-containing brighteners. It is through the research, screening, combination, and optimization of these additives, particularly organic additives, that the growth of copper grains and crystal planes, surface roughness, and texture are altered, thereby affecting PCB product performance.

[0003] Additives in electroplating baths, especially the organic brightener sodium poly(disulfide-bis(propanesulfonate)) (SPS), are susceptible to long-term decomposition under high current density, high acidity, and strong oxygen environments, making them difficult to store stably in the bath. Therefore, it is crucial to be able to monitor the SPS content in the bath in real time and replenish it promptly to meet electroplating requirements. Currently, common methods for detecting SPS include cyclic voltammetric stripping (CVS) and high-performance liquid chromatography (HPLC). These methods are often cumbersome and can only detect the overall brightener content, not specific individual substances. Furthermore, in strong acid environments, they can damage the testing equipment. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the present invention aims to provide a rapid detection method for sodium polydisulfide dipropane sulfonate.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A rapid detection method for polydipropylene glycol disulfide sodium salt comprises the following steps:

[0007] Step 1, solution preparation: prepare a buffer solution with potassium dihydrogen phosphate and dipotassium hydrogen phosphate, or sodium dihydrogen phosphate and disodium hydrogen phosphate, or ammonium dihydrogen phosphate and diammonium hydrogen phosphate; use the prepared buffer solution to dissolve 5,5'-dithiobis(2-nitrobenzoic acid) to prepare Ellma color developer for later use;

[0008] Step 2: Prepare Cu 2+ and H2SO4 acid copper solution, and then use the acid copper solution to prepare multiple groups of brightener sodium polydisulfide dipropane sulfonate solutions with different concentrations;

[0009] Step 3, pretreatment: NaOH is added to the brightener sodium polydisulfide sulfonate solution to adjust the pH to alkaline, and the alkaline solution containing sodium polydisulfide sulfonate is obtained by filtration; then, an excess of borohydride is added as a reducing agent to reduce the sodium polydisulfide sulfonate in the alkaline solution to a thiol-containing compound, and then an acid is added to react with the remaining reducing agent to remove the excess reducing agent. Finally, the solution is adjusted to neutral or weak alkaline to obtain a test solution;

[0010] Step 4: Absorbance test: Add the test solution to a colorimetric tube, add the Ellma colorimetric reagent prepared in step 1, and then dilute to volume with the buffer solution prepared in step 1. Mix thoroughly to develop color, and then measure the absorbance at 412 nm using a UV-visible spectrophotometer.

[0011] Step 5: The absorbance data of each test solution obtained in step 4 at 412 nm are combined with the concentration of the corresponding brightener sodium polydisulfide sulfonate solution to establish a brightener sodium polydisulfide sulfonate concentration-absorbance standard curve;

[0012] Step 6: For the electrolyte to be tested, after pretreatment according to step 3, perform absorbance test according to step 4. According to the brightener brightener sodium disulfide sulfonate concentration-absorbance standard curve established in step 5, the concentration of sodium disulfide sulfonate in the electrolyte to be tested can be obtained.

[0013] Furthermore, in step 1, the pH of the buffer solution is 7-10.

[0014] Furthermore, in step 1, the concentration of Ellma developer is 1-10 g / L.

[0015] Furthermore, in step three, the reducing agent is one or more of NaBH4, KBH4, LiBH4, and LiAlH4.

[0016] Furthermore, in step 2, the Cu 2+ The concentration is 40-150 g / L, the concentration of sulfuric acid is 40-200 g / L, and the concentration of the brightener sodium polydisulfide dipropane sulfonate solution is 0-50 ppm.

[0017] Furthermore, in step 4, the amount of Ellma developer added is 10-200 μL, the color development temperature is 5-45° C., and the color development time is 10-200 min.

[0018] The beneficial effects of the present invention are:

[0019] (2) The present invention uses boron hydride as a reducing agent and utilizes ultraviolet-visible spectroscopy to achieve rapid detection of the content of the brightener sodium polydisulfide propane sulfonate. The operation is convenient and simple, the detection data is highly accurate, and it can be applied to the detection of electroplating solution additives in different systems.

[0020] (2) The present invention uses boron hydride as a reducing agent. After reducing the brightener SPS, it can be completely removed by adjusting the pH, thereby avoiding the reaction of excess reducing agent with Ellman's developer and affecting the accuracy of the color development reaction;

[0021] (3) The detection method established by the present invention is simple to operate and has low equipment requirements;

[0022] (4) The color developer selected in the present invention reacts rapidly and quantitatively with free thiol groups, and the color is stable for a long time after development;

[0023] (5) The linear correlation of the concentration-absorbance standard curve of the brightener polydisulfide bis(propylene disulfide) sulfonate established by the present invention reaches above 0.999, and the detection limit of the brightener polydisulfide bis(propylene disulfide) sulfonate is 0.5 ppm. The detection data has good repeatability and high accuracy, and the relative error can be controlled below 3%. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 These are color photos of brightener SPS solutions with different concentrations in Example 1 of the present invention;

[0025] Figure 2 The UV-visible spectra of SPS solutions with different concentrations of brightener in Example 1 of the present invention are shown below;

[0026] Figure 3 This is a standard curve of the absorbance of the brightener SPS established in Example 1 of the present invention. DETAILED DESCRIPTION

[0027] The present invention will be further described below in conjunction with the accompanying drawings. It should be noted that this embodiment is based on the technical solution and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to this embodiment.

[0028] Example 1

[0029] This embodiment provides a rapid detection method for polydipropylene glycol disulfide sodium sulfonate, comprising the following steps:

[0030] (1) Weigh 5.59 g K2HPO4 and 0.41 g KH2PO4 into a 1 L volumetric flask to prepare a buffer solution with a pH of 7.8;

[0031] (2) Weigh 20 mg of 5,5'-dithiobis(2-nitrobenzoic acid) and add 4 mL of pH 7.8 buffer solution to prepare 4 g / L Ellman color reagent;

[0032] (3) Preparation containing 65g / L Cu 2+ and 80g / L H2SO4 acid copper solution, and then the acid copper solution was used to prepare 0ppm, 4ppm, 8ppm, 12ppm, 16ppm and 20ppm of brightener sodium polydisulfide dipropane sulfonate (SPS) solutions; the color development photos of brightener SPS solutions with different concentrations are shown in the figure below. Figure 1 shown.

[0033] (4) Add 1M NaOH solution to the brightener SPS solution under rapid stirring. When the pH reaches 7-10, filter the solution to remove the precipitate. Add 2mg NaBH4 to the filtrate. After half an hour of reaction, add sulfuric acid to adjust the solution to pH = 4. After another half an hour of reaction, add NaOH to adjust the pH to 7-10. The chemical reaction in step (4) includes:

[0034]

[0035] NaBH4+H + +3H2O=H3BO3+Na + +4H2↑

[0036] H + +OH - =H2O

[0037] (5) Take 1 mL of each solution obtained in step (4) and add 100 μL of Ellman color developer, dilute to 10 mL with buffer solution, mix thoroughly for 10 min at 25°C, and then measure the absorbance at 412 nm using a UV-visible spectrophotometer; the UV-visible spectra of brightener SPS solutions with different concentrations are shown in the figure below. Figure 2 shown.

[0038] (6) Based on the absorbance data at 412 nm and combined with the SPS concentration, a standard curve of brightener SPS concentration-absorbance was established, such as Figure 3 As shown, the fitted equation is y=0.01059x+0.01436, and the linear correlation is r 2 =0.99906.

[0039] (7) For the electrolyte to be tested, after preparing the Ellman color developer and buffer solution according to steps (1) and (2), the solution was treated according to step (4), and then 100 μL of Ellman color developer was added, the volume was made up to 10 mL with buffer solution, and the solution was fully mixed and color developed at 25°C for 10 minutes. The absorbance at 412 nm was then measured using a UV-visible spectrophotometer. The concentration of sodium polydisulfide dipropane sulfonate in the electrolyte to be tested was obtained using the brightener SPS concentration-absorbance standard curve established in step (5).

[0040] Example 2

[0041] The difference between Example 2 and Example 1 is that in step (3), a solution containing 40 g / L Cu 2+ and 100g / L H2SO4 acid copper solution, and then the acid copper solution was used to prepare 0ppm, 4ppm, 8ppm, 12ppm, 16ppm and 20ppm brightener SPS solutions. In step (4), 2M NaOH solution was added under rapid stirring. When the pH reached 7-10, the solution was filtered to remove the precipitate. 2mg NaBH4 was added to the filtrate. After half an hour of reaction, sulfuric acid was added to adjust the solution to pH 4. After another half an hour of reaction, NaOH was added to adjust the pH to 7-10.

[0042] Example 3

[0043] The difference between Example 3 and Example 1 is that in step (3), the preparation of 2+ and 80g / L H2SO4 acid copper solution, and then use the acid copper solution to prepare 0ppm, 4ppm, 8ppm, 12ppm, 16ppm and 20ppm brightener SPS solutions; in step (4), 1M NaOH solution is added under rapid stirring, and when the pH reaches 7-10, the solution is filtered to remove the precipitate, 4mg KBH4 is added to the filtrate, and after reacting for half an hour, sulfuric acid is added to adjust the solution to pH=3, and after reacting for another half an hour, NaOH is added to adjust the pH to 7-10.

[0044] Example 4

[0045] The difference between Example 4 and Example 1 is that in step (5), 5 mL of each solution obtained in step (4) was added to 200 μL of Ellma color developer, the volume was adjusted to 25 mL with buffer solution, and the solution was thoroughly mixed and color developed at 25°C for 10 minutes, and then the absorbance at 412 nm was measured using a UV-visible spectrophotometer.

[0046] Those skilled in the art can make various corresponding changes and modifications based on the above technical solutions and concepts, and all of these changes and modifications should be included in the scope of protection of the claims of the present invention.

Claims

1. A rapid detection method for polydisulfide dipropane sulfonate sodium, characterized in that: The steps include: Step 1, solution preparation: prepare a buffer solution with potassium dihydrogen phosphate and dipotassium hydrogen phosphate, or sodium dihydrogen phosphate and disodium hydrogen phosphate, or ammonium dihydrogen phosphate and diammonium hydrogen phosphate; use the prepared buffer solution to dissolve 5,5'-dithiobis(2-nitrobenzoic acid) to prepare Ellma color developer for later use; Step 2: Prepare Cu 2+ and H2SO4 acid copper solution, and then use the acid copper solution to prepare multiple groups of brightener sodium polydisulfide dipropane sulfonate solutions with different concentrations; Step 3, pretreatment: NaOH is added to the brightener sodium polydisulfide sulfonate solution to adjust the pH to alkaline, and the alkaline solution containing sodium polydisulfide sulfonate is obtained by filtration; then, an excess of borohydride is added as a reducing agent to reduce the sodium polydisulfide sulfonate in the alkaline solution to a thiol-containing compound, and then an acid is added to react with the remaining reducing agent to remove the excess reducing agent. Finally, the solution is adjusted to neutral or weak alkaline to obtain a test solution; Step 4: Absorbance test: Add the test solution to a colorimetric tube, add the Ellma colorimetric reagent prepared in step 1, and then dilute to volume with the buffer solution prepared in step 1. Mix thoroughly to develop color, and then measure the absorbance at 412 nm using a UV-visible spectrophotometer. Step 5: The absorbance data of each test solution obtained in step 4 at 412 nm are combined with the concentration of the corresponding brightener sodium polydisulfide sulfonate solution to establish a brightener sodium polydisulfide sulfonate concentration-absorbance standard curve; Step 6: For the electrolyte to be tested, after pretreatment according to step 3, perform absorbance test according to step 4. According to the brightener sodium polydisulfide sulfonate concentration-absorbance standard curve established in step 5, the concentration of sodium polydisulfide sulfonate in the electrolyte to be tested can be obtained.

2. The method according to claim 1, characterized in that In step 1, the pH of the buffer solution is 7-10.

3. The method according to claim 1, characterized in that In step 1, the concentration of Ellma color developer is 1-10 g / L.

4. The method according to claim 1, wherein In step 3, the reducing agent is one or more of NaBH4, KBH4, LiBH4, and LiAlH4.

5. The method according to claim 1, wherein In step 2, Cu in the acid copper solution 2+ The concentration is 40-150 g / L, the concentration of sulfuric acid is 40-200 g / L, and the concentration of the brightener sodium polydisulfide dipropane sulfonate solution is 0-50 ppm.

6. The method according to claim 1, characterized in that In step 4, the amount of Ellma color developer added is 10-200 μL, the color development temperature is 5-45° C., and the color development time is 10-200 min.

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