High performance liquid chromatography analysis method for effective components of additive in electroplating solution

Abstract

The invention discloses a high performance liquid chromatography analysis method for effective components of additives in electroplating liquid, which comprises the following steps: analyzing EN (n is equal to 6) and ENSA (n is equal to 6) by utilizing a high performance liquid chromatograph and adopting a buffer solution system-reversed phase liquid chromatography, and displaying analysis results on the same chromatogram. Effective components of the additive in the electroplating liquid can be rapidly and effectively detected, and a quality guarantee is provided for the electroplating process.

Description

Technical Field

[0001] This invention relates to the field of electroplating solution detection, and more particularly to a high-performance liquid chromatography (HPLC) method for analyzing the effective components of additives in electroplating solutions. Background Technology

[0002] Florstein tin plating is a process developed by USSteel, using a tin plating solution based on stannous sulfate, with added additives and a sulfuric acid system. This type of solution can operate at high current densities, which is highly advantageous for high-speed electroplating. Currently, the Florstein tin plating processes used domestically and internationally fall into two categories: one is the soluble anode system represented by those from Europe and America; the other is the insoluble anode system represented by those from modern Japan. Our company uses the PSA-type insoluble anode system; in the PSA insoluble anode system, the plating solution mainly consists of Sn... 2+ It consists of phenol sulfonic acid (PSA), organic additives EN (n=6) and ENSA (n=6). Phenol sulfonic acid is prepared by mixing concentrated sulfuric acid and phenol in a certain proportion, and its function is to provide SO4 for the conductive salt in electroplating. 2- This ensures the electroplating solution maintains good conductivity. Additionally, phenolsulfonic acid and Sn... 2+ It undergoes complexation, thus inhibiting Sn. 2+ It is oxidized, reducing the amount of tin sludge produced.

[0003] EN (n=6) is an α-naphthol polyoxyethylene ether prepared by the ethoxylation polymerization reaction of α-naphthol and ethylene oxide. EN (n=6) is a surfactant whose role in the plating bath is to increase the optimal current density for tin plating, improve the dispersibility of the plating bath, and make the tin plating layer smooth, bright, and dense. In addition, EN (n=6) acts as a dispersant, dispersing the anodic oxidation modification products of phenolsulfonic acid and its salts, preventing them from polymerizing and adhering to the surface of the tin-plated plate.

[0004] ENSA (n=6) is an α-naphthol sulfonate polyoxyethylene ether obtained by sulfonation of EN (n=6). Due to incomplete sulfonation, industrially prepared ENSA (n=6) is a mixture of 50% ENSA (n=6) and 40% unsulfonated EN (n=6).

[0005] The main active components in electroplating solutions are EN (n=6) and ENSA (n=6). Current detection methods employ spectrophotometry, using ENSA (n=6) stock solution extracted and separated to obtain EN (n=6) and ENSA (n=6) solutions as standards to construct a standard curve for determining the EN (n=6) and ENSA (n=6) content in the plating solution. The structural formulas of EN (n=6) and ENSA (n=6) are as follows:

[0006] EN (n=6)

[0007] ENSA (n=6) The active components EN (n=6) and ENSA (n=6) in the electroplating solution are a mixture of their respective average polymers with an average value of n=6. Standards can only be separated and purified from the ENSA (n=6) stock solution. Due to the similar structures of the two compounds, simple extraction methods are insufficient for effective separation, leading to significant fluctuations in detection results. This is a major problem hindering current analytical methods—spectroscopy. Summary of the Invention

[0008] To address the shortcomings of existing technologies, the present invention aims to provide a high-performance liquid chromatography (HPLC) method for analyzing the effective components of additives in electroplating solutions. This method utilizes an HPLC instrument and employs a buffer solution system-reversed-phase HPLC approach to analyze EN (n=6) and ENSA (n=6), displaying the analytical results on a single chromatogram. This method allows for rapid and effective detection of the effective components of additives in electroplating solutions, providing a quality assurance for the electroplating process.

[0009] To achieve the above objectives, the present invention adopts the following technical solution:

[0010] This invention provides a high-performance liquid chromatography (HPLC) method for analyzing the effective components of additives in electroplating solutions, comprising the following steps:

[0011] S1, set the high-performance liquid chromatography conditions;

[0012] S2, Standard sample preparation: The ENSA stock solution was extracted, separated and purified using a benzene-saturated sodium chloride solution system, and standard samples of EN (n=6) and ENSA (n=6) were prepared.

[0013] S3. Establish standard curves. Using the conditions set in step S1, reversed-phase liquid chromatography is used to determine the standard samples of EN (n=6) and ENSA (n=6) respectively. Standard curves of EN (n=6) and ENSA (n=6) are established with concentration as the abscissa and peak area as the ordinate.

[0014] S4, Sample preparation: Prepare the electroplating solution into the sample to be tested;

[0015] S5. Using the conditions set in step S1, the sample to be tested is subjected to reversed-phase liquid chromatography to obtain a high-performance liquid chromatogram of the sample to be tested, and the contents of EN (n=6) and ENSA (n=6) in the electroplating solution are obtained according to the standard curve in step S3.

[0016] Preferably, in step S1, the high-performance liquid chromatography conditions are as follows:

[0017] Chromatographic column: C18 column;

[0018] Mobile phase: comprising an organic phase and an aqueous phase, wherein the ratio of the organic phase to the aqueous phase is 30-70:70-30; the organic phase is one or both of methanol and acetonitrile; the aqueous phase is phosphate buffer.

[0019] Flow rate: 0.8–1.2 mL / min;

[0020] Column temperature: 25~40℃;

[0021] Detection wavelength: 215nm;

[0022] Injection volume: 20 μL.

[0023] Preferably, the concentration of the phosphate buffer solution is 10–100 mmol / L, and the pH is adjusted to 2–5 with phosphate.

[0024] Preferably, the phosphate is selected from one or more of disodium hydrogen phosphate, sodium dihydrogen phosphate, dipotassium hydrogen phosphate, and potassium dihydrogen phosphate.

[0025] Preferably, step S2 includes the following steps:

[0026] S21, the ENSA stock solution was extracted, separated and purified using a benzene-saturated sodium chloride solution system to obtain crude EN (n=6) and crude ENSA (n=6), which were then dissolved and filtered with anhydrous ethanol to obtain EN (n=6) and ENSA (n=6) standards, respectively.

[0027] S22, Prepare EN (n=6) standard and ENSA (n=6) standard into EN (n=6) solution and ENSA (n=6) solution respectively using pure water;

[0028] S23, using liquid chromatography as the mobile phase, prepare standard samples of EN(n=6) and ENSA(n=6) with different concentration gradients, respectively.

[0029] Preferably, in step S21, the purity of the EN (n=6) standard is ≥97.0%, and the purity of the ENSA (n=6) standard is ≥95.0%.

[0030] Preferably, in step S23, the concentration range of the EN (n=6) standard sample is 0 to 300 μg / mL, and the concentration range of the ENSA (n=6) standard sample is 0 to 300 μg / mL.

[0031] Preferably, in step S4, the sample to be tested is configured in the following manner:

[0032] Take 1-2 mL of electroplating solution into a 25 mL volumetric flask, dilute to volume using the mobile phase for liquid chromatography analysis, let stand for 30-35 min, filter the precipitate to obtain the sample to be tested.

[0033] The beneficial effects of this invention are as follows:

[0034] 1. Existing analytical methods using spectrophotometry cannot meet the requirements of modern industrial quality control. This invention uses high-performance liquid chromatography (HPLC) with a reasonable buffer system and reversed-phase chromatography to analyze the effective components of additives EN (n=6) and ENSA (n=6) in electroplating solutions. This allows for effective quantitative analysis of both EN (n=6) and ENSA (n=6), achieving efficient, scientific, and rapid analysis, and providing a quality guarantee for the electroplating process.

[0035] 2. The method of the present invention has the advantages of being fast, effective, and highly repeatable. It can monitor the changes in the composition of the electroplating solution in real time and guide the precise control of the plating solution process.

[0036] 3. Using the method of the present invention, the analytical results of EN (n=6) and ENSA (n=6) can be displayed on the same chromatogram, which can quickly and effectively detect the active components of additives EN (n=6) and ENSA (n=6) in electroplating solutions. Attached Figure Description

[0037] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0038] Figure 1 This is a schematic flowchart of the high-performance liquid chromatography method for analyzing the effective components of additives in the electroplating solution according to the present invention.

[0039] Figure 2 The UV scan image is for the EN (n=6) standard.

[0040] Figure 3 The image shows the UV scan of the ENSA (n=6) standard.

[0041] Figure 4 This is a UV scan of the electroplating solution sample;

[0042] Figure 5 The HPLC chromatogram of the EN (n=6) standard;

[0043] Figure 6 The HPLC chromatogram of ENSA (n=6) standard;

[0044] Figure 7 The HPLC chromatogram of the sample to be tested in the electroplating solution;

[0045] Figure 8 The standard curve for EN (n=6) standard solutions;

[0046] Figure 9 The standard curve is for ENSA (n=6) standard solutions. Detailed Implementation

[0047] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way.

[0048] Current techniques employ spectrophotometry, utilizing extraction to separate ENSA (n=6) stock solution to obtain EN(n=6) and ENSA (n=6) solutions as standards to construct a standard curve for determining the EN(n=6) and ENSA (n=6) content in the plating bath. EN(n=6) and ENSA (n=6) are a mixture of their respective average polymers with an n=6 value, and the standard can only be separated and purified from the ENSA (n=6) stock solution. Due to the similar structures of the two compounds, simple extraction methods are insufficient for effective separation, leading to significant fluctuations in the detection results.

[0049] Combination Figure 1 As shown, the high-performance liquid chromatography (HPLC) method for analyzing the effective components of additives in electroplating solutions provided by this invention includes the following steps:

[0050] S1, set the high-performance liquid chromatography conditions as follows:

[0051] Chromatographic column: C18 column (octadecyl silica bonded column), 150mm × 4.6mm, 5μm;

[0052] Mobile phase: includes an organic phase and an aqueous phase, with the ratio of organic phase to aqueous phase being 30-70:70-30; the organic phase uses one or two of methanol and acetonitrile; the aqueous phase uses phosphate buffer, with a concentration of 10-100 mmol / L, and the pH is adjusted to 2-5 with phosphoric acid, and the phosphate is one or more of disodium hydrogen phosphate, sodium dihydrogen phosphate, dipotassium hydrogen phosphate, and potassium dihydrogen phosphate.

[0053] Flow rate: 0.8–1.2 mL / min;

[0054] Column temperature: 25~40℃;

[0055] Detection wavelength: 215nm;

[0056] Injection volume: 20 μL.

[0057] S2, Standard sample preparation: The ENSA stock solution was extracted, separated and purified using a benzene-saturated sodium chloride solution system, and standard samples of EN (n=6) and ENSA (n=6) were prepared.

[0058] S21, the ENSA stock solution was extracted, separated and purified using a benzene-saturated sodium chloride solution system to obtain crude EN (n=6) and crude ENSA (n=6), which were then dissolved and filtered with anhydrous ethanol to obtain EN (n=6) and ENSA (n=6) standards, respectively.

[0059] During extraction, separation, and purification, take the ENSA stock solution, add saturated sodium chloride solution, add benzene into a separatory funnel, shake thoroughly to make the solution emulsion, and allow it to stand to separate into layers. The upper layer is a benzene layer containing EN (n=6), the middle layer is an aqueous layer containing ENSA (n=6), and the lower layer is an aqueous layer containing PSA and other substances.

[0060] The benzene layer was placed in a separatory funnel and extracted with saturated sodium chloride solution by shaking. The extraction was repeated three or more times using the same method. After removing the benzene by rotary evaporation, crude EN (n=6) was obtained.

[0061] The crude EN (n=6) product was dissolved in anhydrous ethanol and filtered to remove sodium chloride. The product was then washed three times using the same method to obtain the EN (n=6) standard. Ash content analysis showed it contained 0.34% inorganic salts.

[0062] The above EN (n=6) standard was diluted to volume with the mobile phase for high performance liquid chromatography analysis, and the purity was determined by high performance liquid chromatography under the conditions in step S3. The purity was ≥97%.

[0063] The intermediate ENSA (n=6) aqueous layer was removed and placed in a separatory funnel. Benzene and saturated sodium chloride solution were added, and the mixture was thoroughly shaken and extracted. The extraction was repeated three or more times using the same method. After removing water by rotary evaporation, crude ENSA (n=6) was obtained.

[0064] The crude ENSA (n=6) was dissolved in anhydrous ethanol and filtered to remove sodium chloride. The solution was washed three times using the same method to obtain the EN (n=6) standard. Ash content determination showed it contained 4.95% inorganic salts.

[0065] The mobile phase of the above ENSA (n=6) standard was adjusted to a constant volume using high performance liquid chromatography (HPLC), and the purity was determined by HPLC under the conditions described in step S3. The purity was ≥95.0%.

[0066] Ultraviolet (UV) spectroscopy was used to scan the EN (n=6) standard, ENSA (n=6) standard, and electroplating solution. The results are as follows: Figure 2 , Figure 3 and Figure 4 As shown, it can be found that its maximum absorption is around 200nm. Considering the characteristics of high performance liquid chromatography, the present invention selects an ultraviolet detection wavelength of 215nm for subsequent detection.

[0067] S22, Prepare EN (n=6) standard and ENSA (n=6) standard into EN (n=6) solution and ENSA (n=6) solution respectively using pure water;

[0068] Accurately weigh 80.0 mg of purified standard EN (n=6) into a 25 mL volumetric flask, dilute to volume with pure water, and prepare an EN (n=6) solution;

[0069] Accurately weigh 80.0 mg of purified standard ENSA (n=6) into a 25 mL volumetric flask, dilute to volume with pure water, and prepare an EN (n=6) solution.

[0070] S23, using liquid chromatography as the mobile phase, prepare standard samples of EN(n=6) and ENSA(n=6) with different concentration gradients, respectively.

[0071] Take 0 mL, 0.5 mL, 1.0 mL, 1.5 mL and 2.0 mL of the EN(n=6) solution prepared in step S22 into five 25 mL volumetric flasks respectively, and dilute to volume with the mobile phase of high performance liquid chromatography to obtain EN(n=6) standard samples with different concentration gradients. The concentration range of the EN(n=6) standard samples is 0 to 300 μg / mL.

[0072] Take 0 mL, 0.5 mL, 1.0 mL, 1.5 mL, and 2.0 mL of the ENSA (n=6) solution prepared in step S22 into five 25 mL volumetric flasks, respectively, and dilute to volume with the mobile phase for high performance liquid chromatography to obtain ENSA (n=6) standard samples with different concentration gradients. The concentration range of the ENSA (n=6) standard samples is 0–300 μg / mL.

[0073] S3. Establish standard curves. Using the conditions set in step S1, reversed-phase liquid chromatography is used to determine the standard samples of EN (n=6) and ENSA (n=6) respectively. Standard curves of EN (n=6) and ENSA (n=6) are established with concentration as the abscissa and peak area as the ordinate.

[0074] S4, Sample preparation: Prepare the electroplating solution into the sample to be tested;

[0075] Because the electroplating solution contains a large amount of metal ions Sn 2+ Metal ions Fe 2+ And H2SO4, because these substances are very damaging to the chromatographic column, they need to be properly removed before entering the column. This invention uses a phosphate buffer solution at a specific pH value to precipitate Sn. 2+ Metal ions Fe 2+ And neutralize H2SO4.

[0076] The sample to be tested is prepared in the following manner:

[0077] Take 1-2 mL of electroplating solution into a 25 mL volumetric flask, dilute to volume using the mobile phase for liquid chromatography analysis, let stand for 30-35 min, filter the precipitate through a 0.22 μm filter head to obtain the sample to be tested.

[0078] S5. Using the conditions set in step S1, the sample to be tested is subjected to reversed-phase liquid chromatography to obtain a high-performance liquid chromatogram of the sample to be tested, and the contents of EN (n=6) and ENSA (n=6) in the electroplating solution are obtained according to the standard curve in step S3.

[0079] The sample to be tested in step S4 was subjected to reversed-phase liquid chromatography under the conditions set in step S1 using a high-performance liquid chromatograph. The analytical results of EN (n=6) and ENSA (n=6) were displayed on the same chromatogram. Based on the peak area and combined with the standard curve in step S3, the contents of EN (n=6) and ENSA (n=6) in the electroplating solution were obtained.

[0080] The method of this invention can analyze the changes in the content of the active additive components EN (n=6) and ENSA (n=6) in the actual electroplating solution in real time and quickly, thereby enabling precise control of the electroplating process. When the content of EN (n=6) and ENSA (n=6) in the electroplating solution is low, it can be replenished in time.

[0081] The following section provides a specific example to further illustrate a high-performance liquid chromatography (HPLC) method for analyzing the effective components of additives in an electroplating solution according to the present invention.

[0082] Example

[0083] The high-performance liquid chromatography (HPLC) method for analyzing the effective components of the additives in the electroplating solution in this embodiment is as follows:

[0084] (1) High performance liquid chromatography conditions

[0085] The chromatographic conditions used were as follows: a C18 column (150 mm × 4.6 mm, 5 μm); a mobile phase consisting of an aqueous phase and an organic phase; the aqueous phase being a 10-100 mmol / L phosphate buffer solution, with the pH adjusted to 2-5 using phosphoric acid; and the organic phase being one or both of methanol and acetonitrile, with an organic-to-aqueous phase ratio of 30-70:70-30; a flow rate of 1.0 mL / min; a column temperature of 25-50 °C; and a detector wavelength of 215 nm.

[0086] (2) Preparation of standard samples and standard curve

[0087] Weigh 10g of ENSA (n=6) stock solution, add 50mL of saturated sodium chloride solution, add 50mL of benzene to a 250mL separatory funnel, shake thoroughly to form an emulsion, and allow to stand to separate into layers. The upper layer is a benzene layer containing EN (n=6), the middle layer is an aqueous layer containing ENSA (n=6), and the lower layer is an aqueous layer containing PSA and other substances.

[0088] The benzene layer containing EN (n=6) was placed into another 250mL separatory funnel, and saturated sodium chloride solution was added and shaken for extraction. The extraction was repeated three or more times using the same method. After removing the benzene by rotary evaporation, crude EN (n=6) product was obtained.

[0089] The intermediate ENSA (n=6) aqueous layer was removed and placed in a 125 mL separatory funnel. 25 mL of benzene and 25 mL of saturated sodium chloride solution were added, and the mixture was thoroughly shaken and extracted. The extraction was repeated three or more times using the same method. After removing the water by rotary evaporation, crude ENSA (n=6) was obtained.

[0090] The crude EN (n=6) product was dissolved in anhydrous ethanol and filtered to remove sodium chloride. The product was then washed three times using the same method to obtain the EN (n=6) standard. Ash content determination showed that it contained 0.34% inorganic salts.

[0091] The crude ENSA (n=6) was dissolved in anhydrous ethanol and filtered to remove sodium chloride. The solution was washed three times using the same method to obtain the ENSA (n=6) standard. Ash content determination showed it contained 4.95% inorganic salts.

[0092] The EN (n=6) standard, ENSA (n=6) standard, and electroplating solution were subjected to ultraviolet spectroscopy scanning. (See [reference needed]) Figure 2 , Figure 3 , Figure 4 As can be seen from the figure, its maximum absorption is around 200nm. Based on the characteristics of high performance liquid chromatography, the ultraviolet detection wavelength is selected as 215nm in this embodiment.

[0093] The purified EN (n=6) standard was diluted to volume using the mobile phase for high-performance liquid chromatography (HPLC) and analyzed under the HPLC conditions set in step (1). The purity was 97.2%. See [link to relevant documentation]. Figure 5 .

[0094] The purified ENSA (n=6) standard was diluted to volume using the mobile phase for high-performance liquid chromatography (HPLC) and analyzed under the HPLC conditions set in step (1). The purity was 95.0%. See [link to relevant documentation]. Figure 6 .

[0095] Accurately weigh 80.0 mg of purified EN (n=6) standard into a 25 mL volumetric flask and dilute to volume with pure water to obtain an EN (n=6) solution. Take 0, 0.5, 1.0, 1.5, and 2.0 mL of each solution into five 25 mL volumetric flasks, respectively, and dilute to volume with the mobile phase for high-performance liquid chromatography (HPLC). Perform the HPLC analysis according to the HPLC conditions set in step (1). Construct a standard curve for EN (n=6) with the concentration of EN (n=6) as the x-axis and the peak area as the y-axis. See [reference needed]. Figure 9 As shown, its regression formula is y = 18.639x + 3.19(R²). 2 =0.9999);

[0096] Accurately weigh 80.0 mg of purified ENSA (n=6) standard into a 25 mL volumetric flask and dilute to volume with pure water to obtain an ENSA (n=6) solution. Take 0, 0.5, 1.0, 1.5, and 2.0 mL of each solution into five 25 mL volumetric flasks, respectively, and dilute to volume with the mobile phase for high-performance liquid chromatography (HPLC). Perform the HPLC analysis according to the conditions set in step (1). Construct a standard curve for ENSA (n=6) with the concentration of ENSA (n=6) as the x-axis and the peak area as the y-axis. (See [reference needed]). Figure 9 As shown, its regression formula is y = 126.86x + 99.6(R²). 2 =0.9999);

[0097] (3) Sample preparation and determination

[0098] Because the plating solution contains a large amount of metal ions Sn 2+ Metal ions Fe 2+ And H2SO4, because these substances are very damaging to the chromatographic column, they need to be properly removed before entering the column. This invention uses a phosphate buffer solution at a specific pH value to precipitate Sn. 2+ Metal ions Fe 2+ And neutralize H2SO4.

[0099] Take 1 mL of electroplating solution into a 25 mL volumetric flask, dilute to volume with the mobile phase for high performance liquid chromatography (HPLC), let stand for 30 min, filter the precipitate using a 0.22 μm filter head, and perform HPLC analysis according to the conditions set in step (1). The results of EN (n=6) and ENSA (n=6) can be displayed on the same HPLC chromatogram. See [link to relevant documentation]. Figure 7 As shown, calculate the peak areas of EN (n=6) and ENSA (n=6) based on the HPLC chromatogram, and then... Figure 8 The standard curve of EN (n=6) shown is... Figure 9 The standard curve of ENSA (n=6) is shown. Calculate the EN (n=6) and ENSA (n=6) content of the electroplating solution.

[0100] Based on the specifications of the electroplating process, ENSA (n=6): 2.5±0.5g / L, EN (n=6): 4.5±0.5g / L, and according to the EN (n=6) and ENSA (n=6) content in the electroplating solution tested above, the amount of original EN (n=6) and ENSA (n=6) that need to be added can be calculated.

[0101] The above process can be measured every 2 days, and the results are shown in Table 1.

[0102] Table 1

[0103]

[0104] As shown in Table 1, the method of the present invention has a smaller deviation, basically within 0.05 g / L, while the spectrophotometric method has a larger deviation, around 0.2 g / L. The repeatability of measuring the concentration of additives in tin plating solution by high performance liquid chromatography is significantly higher than that of spectrophotometry.

[0105] In summary, this invention utilizes a high-performance liquid chromatography (HPLC) system with a suitable buffer system and reversed-phase chromatography to analyze EN (n=6) and ENSA (n=6), enabling effective quantitative analysis of both EN (n=6) and ENSA (n=6). This allows for efficient, scientific, and rapid analysis of the content of the effective additive components EN (n=6) and ENSA (n=6) in electroplating solutions, providing a quality assurance for the electroplating process. It can be applied to the tin plating process at Florstein, enabling rapid and accurate detection of the effective additive components in the electroplating solution.

[0106] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A high-performance liquid chromatography (HPLC) method for analyzing the effective components of additives in electroplating solutions, characterized in that, Includes the following steps: S1, set the high-performance liquid chromatography conditions; S2, Standard sample preparation: The ENSA stock solution was extracted, separated and purified using a benzene-saturated sodium chloride solution system, and standard samples of EN (n=6) and ENSA (n=6) were prepared. S3. Establish standard curves. Using the conditions set in step S1, reversed-phase liquid chromatography is used to determine the standard samples of EN (n=6) and ENSA (n=6) respectively. Standard curves of EN (n=6) and ENSA (n=6) are established with concentration as the abscissa and peak area as the ordinate. S4, Sample preparation: Prepare the electroplating solution into the sample to be tested; S5. Using the conditions set in step S1, the sample to be tested is subjected to reversed-phase liquid chromatography to obtain a high-performance liquid chromatogram of the sample to be tested, and the contents of EN (n=6) and ENSA (n=6) in the electroplating solution are obtained according to the standard curve in step S3.

2. The high-performance liquid chromatography method for analyzing the effective components of additives in electroplating solutions as described in claim 1, characterized in that, In step S1, the high-performance liquid chromatography conditions are as follows: Chromatographic column: C18 column; Mobile phase: comprising an organic phase and an aqueous phase, wherein the ratio of the organic phase to the aqueous phase is 30-70:70-30; the organic phase is one or both of methanol and acetonitrile; the aqueous phase is phosphate buffer. Flow rate: 0.8–1.2 mL / min; Column temperature: 25~40℃; Detection wavelength: 215nm; Injection volume: 20 μL.

3. The high-performance liquid chromatography method for analyzing the effective components of additives in electroplating solutions as described in claim 2, characterized in that, The concentration of the phosphate buffer solution is 10–100 mmol / L, and the pH is adjusted to 2–5 with phosphate.

4. The high-performance liquid chromatography method for analyzing the effective components of additives in electroplating solutions as described in claim 3, characterized in that, The phosphate is selected from one or more of disodium hydrogen phosphate, sodium dihydrogen phosphate, dipotassium hydrogen phosphate, and potassium dihydrogen phosphate.

5. The high-performance liquid chromatography method for analyzing the effective components of additives in electroplating solutions as described in claim 1, characterized in that, Step S2 includes the following steps: S21, the ENSA stock solution was extracted, separated and purified using a benzene-saturated sodium chloride solution system to obtain crude EN (n=6) and crude ENSA (n=6), which were then dissolved and filtered with anhydrous ethanol to obtain EN (n=6) and ENSA (n=6) standards, respectively. S22, Prepare EN (n=6) standard and ENSA (n=6) standard into EN (n=6) solution and ENSA (n=6) solution respectively using pure water; S23, using liquid chromatography as the mobile phase, prepare standard samples of EN(n=6) and ENSA(n=6) with different concentration gradients, respectively.

6. The high-performance liquid chromatography method for analyzing the effective components of additives in electroplating solutions as described in claim 5, characterized in that, In step S21, the purity of the EN (n=6) standard is ≥97.0%, and the purity of the ENSA (n=6) standard is ≥95.0%.

7. The high-performance liquid chromatography method for analyzing the effective components of additives in electroplating solutions as described in claim 5, characterized in that, In step S23, the concentration range of the EN (n=6) standard sample is 0 to 300 μg / mL, and the concentration range of the ENSA (n=6) standard sample is 0 to 300 μg / mL.

8. The high-performance liquid chromatography method for analyzing the effective components of additives in electroplating solutions as described in claim 1, characterized in that, In step S4, the sample to be tested is configured in the following manner: Take 1-2 mL of electroplating solution into a 25 mL volumetric flask, dilute to volume using the mobile phase for liquid chromatography analysis, let stand for 30-35 min, filter the precipitate to obtain the sample to be tested.

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