A method for qualitative and quantitative determination of sodium thiopropane sulfonate brightener in acid copper electroplating solution

Abstract

The present invention relates to the technical field of organic matter detection, and in particular to a method for qualitatively and quantitatively determining a sodium thiopropane sulfonate brightener in an acid copper electroplating solution. The method comprises the following steps: (1) dissolving a standard sample of sodium polydisulfide propane sulfonate and sodium 3-mercapto-1-propane sulfonate with an aqueous sulfuric acid solution, preparing standard solutions of different concentrations, injecting into a high performance liquid chromatography-mass spectrometer, using an aqueous ammonium acetate solution / acetonitrile as a mobile phase, and drawing a standard curve; (2) testing the acid copper electroplating solution under the same test conditions as step (1), and calculating the content of sodium polydisulfide propane sulfonate and sodium 3-mercapto-1-propane sulfonate in the acid copper electroplating solution according to the standard curve. The present invention has the advantages of being able to achieve effective separation of sodium polydisulfide propane sulfonate and sodium 3-mercapto-1-propane sulfonate, high precision and recovery, low detection limit and quantitative limit, and high stability.

Description

Technical Field

[0001] The invention relates to the technical field of organic matter detection, and in particular to a method for qualitatively and quantitatively determining a sodium thiopropane sulfonate brightener in an acid copper electroplating solution. Background Art

[0002] Sodium thiopropane sulfonate compounds are mainly used in electroplating acid copper plating and for preparing copper plating brighteners. They are the main additives in copper plating additives and can refine the crystals of the coating and effectively increase the current density. They are particularly suitable for electroplating of printed circuit boards. In the acid copper brightener market, this product is in great demand and has excellent application effects. Since the amount of sodium thiopropane sulfonate added determines the light emission speed and stability of the formula, an appropriate amount of sodium thiopropane sulfonate can significantly regulate the growth and performance of the coating and improve the structure and performance of the coating. Therefore, the content of sodium thiopropane sulfonate is an important indicator for product quality control, and it is very necessary to accurately determine its structure and content.

[0003] At present, the common sodium thiopropane sulfonate brighteners on the market are mainly sodium polydisulfide propane sulfonate (SPS) and sodium 3-mercapto-1-propane sulfonate (MPS), and their chemical structures are shown below:

[0004]

[0005] Since the chemical structures of SPS and MPS are extremely similar, the qualitative and quantitative analysis of the two has always been difficult. At present, the research on sodium thiopropane sulfonate mainly focuses on the quantitative analysis of SPS, including high performance liquid chromatography, derivatization colorimetry, cyclic voltammetry, etc.

[0006] For example, Chinese patent application CN111157520A discloses a detection reagent and a detection method for detecting the content of sodium polydisulfide propane sulfonate in acid copper electroplating solution. The detection reagent used includes a reducing agent, a buffer solution and a color developer, wherein the reducing agent is a reducing agent that reduces the disulfide bonds in the sodium polydisulfide propane sulfonate to thiol groups; the buffer solution is a buffer solution with a pH value of 8 to 10; and the color developer is 5,5'-dithiobis(2-nitrobenzoic acid). This invention provides a derivative color development method, which reduces the disulfide bonds in the sodium polydisulfide propane sulfonate to thiol groups, then adds a color developer, and quantifies by ultraviolet spectrophotometer, but this method has complex sample pretreatment and lengthy test steps.

[0007] Chinese patent application CN105606738A discloses a high-performance liquid chromatography analysis method for sodium polydisulfide propane sulfonate. The high-performance liquid phase analysis method uses a high-performance liquid chromatograph equipped with an ultraviolet detector for determination, with octadecyl bonded silica gel as the filling column, the size of the chromatographic column is 250mm column length × 4.6mm inner diameter, 5μm particle size; the mobile phase is methanol and buffer solution with a volume ratio of 0-50:100-50; the detection wavelength is 190-330nm; the column temperature is 10-60℃; the mobile phase speed is 0.3-1.2mL / min; the sample injection volume is 20μL; wherein the buffer solution is 0.17mol / L acetic acid + 0.142mol / L triethylamine + ultrapure water. The standard curve established by the standard solution can quickly and accurately measure the content of sodium polydisulfide propane sulfonate in the sample to be tested, the measurement result has a small error, strong repeatability, a precision of less than 2.8%, and a recovery rate of 96.7% to 99.3%. However, its detection limit is high and it is difficult to distinguish between SPS and MPS.

[0008] Currently, there have been many reports on the quantitative analysis of SPS, but there are few studies on how to distinguish SPS from MPS, and on the qualitative and quantitative analysis of MPS.

[0009] Therefore, it is very necessary to develop a qualitative and quantitative method for the sodium thiopropane sulfonate brightener in the acid copper electroplating solution that can solve the above-mentioned technical problems. Summary of the invention

[0010] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a method for qualitatively and quantitatively determining a sodium thiopropane sulfonate brightener in an acid copper electroplating solution, which can achieve effective separation of SPS and MPS, high precision and recovery rate, low detection limit and quantitative limit and high stability.

[0011] The present invention is achieved through the following technical solutions:

[0012] A method for qualitatively and quantitatively determining a sodium thiopropane sulfonate brightener in an acid copper electroplating solution, wherein the sodium thiopropane sulfonate brightener comprises sodium polydisulfide propane sulfonate and sodium 3-mercapto-1-propane sulfonate, comprising the following steps:

[0013] (1) dissolving sodium polydisulfide propane sulfonate and sodium 3-mercapto-1-propane sulfonate standard samples in aqueous sulfuric acid to prepare standard solutions of different concentrations, injecting them into a high performance liquid chromatography-mass spectrometer, using ammonium acetate aqueous solution / acetonitrile as the mobile phase, and drawing a standard curve;

[0014] (2) The acid copper electroplating solution is tested under the same test conditions as step (1), and the contents of sodium polydisulfide propane sulfonate and sodium 3-mercapto-1-propane sulfonate in the acid copper electroplating solution are calculated according to a standard curve.

[0015] Preferably, the concentration of the aqueous ammonium acetate solution in step (1) is 5 mmol / L.

[0016] Preferably, in step (1), the volume ratio of the aqueous ammonium acetate solution to acetonitrile is 95:5.

[0017] Preferably, a Waters CORTECS C18 reverse phase chromatography column is used in step (1).

[0018] More preferably, the Waters CORTECS C18 reverse phase chromatography column has a specification of 2.7 μm×2.1 mm×100 mm.

[0019] More preferably, the chromatographic conditions in step (1) are: column temperature 40° C., flow rate 0.2 mL / min, isocratic elution, and injection volume 1 μL.

[0020] Preferably, the mass spectrometry conditions in step (1) are: jet stream electrospray ion source, drying gas temperature 300°C, sheath gas temperature 300°C, drying gas flow rate 5 L / min, sheath gas flow rate 11 L / min, electrospray voltage 45 psi, capillary voltage 4000 V, negative ion scanning, multiple reaction monitoring MRM.

[0021] Preferably, the pH of the aqueous sulfuric acid solution in step (1) is 3.5; standard solutions of different concentrations of 0.05 to 2 mg / L are prepared.

[0022] Preferably, the standard solution and / or the acid copper electroplating solution are filtered through an organic filter membrane before being injected into the triple quadrupole high performance liquid chromatography-mass spectrometer.

[0023] More preferably, the organic filter membrane is 0.22 μm.

[0024] Preferably, the qualitative and quantitative ion pairs of sodium polydisulfide propane sulfonate are 309 / 154.8; and the qualitative and quantitative ion pairs of sodium 3-mercapto-1-propane sulfonate are 155 / 80.

[0025] More preferably, the auxiliary qualitative ion pair of sodium polydipropane disulfide sulfonate is 309 / 81; and the auxiliary qualitative ion pair of sodium 3-mercapto-1-propane sulfonate is 155 / 121.

[0026] Preferably, the high performance liquid chromatography-mass spectrometer is a triple quadrupole high performance liquid chromatography-mass spectrometer.

[0027] Preferably, the purity of the sodium polydisulfide propane sulfonate standard sample is above 97%, and the purity of the sodium 3-mercapto-1-propane sulfonate standard sample is above 90%.

[0028] The beneficial effects of the present invention are:

[0029] 1. Based on the difference in quantitative ions between SPS and MPS, the present invention uses a triple quadrupole high performance liquid chromatography-mass spectrometer to achieve effective separation of SPS and MPS, and then accurately quantify them.

[0030] 2. In the concentration range of 0.05-2 mg / L, the linear correlation coefficient of the standard curve of the present invention is greater than 0.9999, the precision is less than 2.0%, the recovery rate is 96.5%-107.4%, the detection limits of MPS and SPS are as low as 0.003 mg / L and 0.004 mg / L respectively, and the quantitative limit is as low as 0.01 mg / L. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is the standard curve of sodium polydisulfide propane sulfonate and sodium 3-mercapto-1-propane sulfonate.

[0032] Figure 2 The chromatograms are of sodium polydisulfide propane sulfonate and sodium 3-mercapto-1-propane sulfonate in the ammonium acetate aqueous solution (5 mmol / L) / acetonitrile volume ratios of 90:5 and 95:5.

[0033] Figure 3 It is a chromatogram of sodium polydisulfide propane sulfonate and sodium 3-mercapto-1-propane sulfonate in ammonium acetate aqueous solution / acetonitrile (95:5, v / v) when the ammonium acetate content in the ammonium acetate aqueous solution is 2.5, 5, and 10 mmol / L. DETAILED DESCRIPTION

[0034] The present invention will be further described below in conjunction with specific embodiments, and the advantages and features of the present invention will become clearer as the description proceeds. However, these embodiments are exemplary only and do not constitute any limitation to the scope of the present invention. It should be understood by those skilled in the art that the details and forms of the technical solution of the present invention may be modified or replaced without departing from the spirit and scope of the present invention, but these modifications and replacements all fall within the scope of protection of the present invention.

[0035] Example 1

[0036] 1) Test conditions:

[0037] A triple quadrupole high performance liquid chromatography-mass spectrometer equipped with a jet stream electrospray ion source was used as the test instrument.

[0038] Waters CORTECS C18 reverse phase column (2.7um×2.1mm×100mm), column temperature 40°C, flow rate 0.2mL / min, ammonium acetate aqueous solution (5mmol / L) / acetonitrile as mobile phase (95:5, v / v), isocratic elution, injection volume 1μL.

[0039] Jet stream electrospray ion source, drying gas temperature 300°C, sheath gas temperature 300°C, drying gas flow rate 5 L / min, sheath gas flow rate 11 L / min, electrospray voltage 45 psi, capillary voltage 4000 V, negative ion scanning, multiple reaction monitoring (MRM).

[0040] 2) Standard curve of sodium polydisulfide propane sulfonate and sodium 3-mercapto-1-propane sulfonate:

[0041] 0.01 g of sodium polydisulfide propane sulfonate and 0.01 g of sodium 3-mercapto-1-propane sulfonate were accurately weighed, and 10 mL of sodium polydisulfide propane sulfonate and sodium 3-mercapto-1-propane sulfonate were dissolved in sulfuric acid solution (pH=3.5) to prepare a 1000 mg / L mixed standard solution of sodium polydisulfide propane sulfonate and sodium 3-mercapto-1-propane sulfonate, which was further diluted with sulfuric acid solution (pH=3.5) to prepare a mixed standard solution of 10 mg / L and 1 mg / L. Different volumes of solution were taken from the mixed standard solutions of 10 mg / L and 1 mg / L, and diluted with sulfuric acid solution (pH=3.5) to prepare mixed standard solutions of 0.05 mg / L, 0.1 mg / L, 0.2 mg / L, 0.5 mg / L, 1 mg / L, and 2 mg / L, which were filtered with a 0.22 μm organic filter membrane and analyzed on a machine according to the test conditions of 1). Each mixed standard solution was tested 3 times, and the average results were taken. The peak areas of sodium dipropane sulfonate and sodium 3-mercapto-1-propane sulfonate are taken as the ordinate, and the mass concentrations of sodium polydipropane sulfonate and sodium 3-mercapto-1-propane sulfonate are taken as the abscissa. The standard curve is: sodium polydipropane sulfonate y=344.1x-5.6; sodium 3-mercapto-1-propane sulfonate y=258.7x-3.5. The linear range is 0.05mg / L~2mg / L, and the correlation coefficient is not less than 0.9999. See the attached figure. Figure 1 .

[0042] 3) Precision and recovery rate:

[0043] Take 3 portions of blank deionized water, adjust the pH to 3.5 with sulfuric acid, then add 50μL, 200μL of 10mg / L mixed standard solution, 200μL of 100mg / L mixed standard solution, the spiked concentrations are 0.05mg / L, 0.2mg / L, 2mg / L, respectively, and dilute to 10mL to obtain sample solution. The sample solution is filtered through a 0.22μm organic filter membrane and analyzed on the machine according to the test conditions of 1). Each concentration point is tested independently 3 times. The precision and recovery of sodium polydisulfide dipropane sulfonate are 0.8% to 1.9% and 99.7% to 107.4%, respectively, and the precision and recovery of sodium 3-mercapto-1-propane sulfonate are 0.8% to 1.6% and 96.5% to 106.5%, respectively. The results are shown in Table 1.

[0044] Table 1 Calculation of precision and spike recovery

[0045]

[0046]

[0047] 4) Detection limit and quantification limit:

[0048] Take 10 portions of blank deionized water, adjust the pH to 3.5 with sulfuric acid, add 50 μL of 10 mg / L mixed standard solution, the spiked concentration is 0.05 mg / L, and the volume is fixed to 10 mL. The sample solution is filtered through a 0.22 μm organic filter membrane and analyzed on the machine according to the test conditions of 1). 10 independent analyses were performed. The detection limit and quantification limit of sodium polydisulfide propane sulfonate were 0.003 mg / L and 0.01 mg / L, respectively, and the detection limit and quantification limit of sodium 3-mercapto-1-propane sulfonate were 0.0036 mg / L and 0.012 mg / L, respectively. The results are shown in Table 2.

[0049] Table 2 Calculation of detection limit and quantification limit

[0050]

[0051] Note: Detection limit = 3 × standard deviation; Quantification limit = 10 × standard deviation.

[0052] 5) Method stability:

[0053] Take 6 portions of blank deionized water, adjust the pH to 3.5 with sulfuric acid, add 50 μL of 10 mg / L mixed standard solution, the spiked concentration is 0.05 mg / L, the volume is fixed to 10 mL, the sample solution is filtered through a 0.22 μm organic filter membrane, and analyzed on the machine according to the test conditions of 1). 6 independent analyses were performed. The precisions of sodium polydisulfide dipropane sulfonate and sodium 3-mercapto-1-propane sulfonate were 0% and 3.87%, respectively, indicating that the test method is stable. The results are shown in Table 3.

[0054] Table 3 Precision calculation

[0055]

[0056] 6) Detection and recovery of sodium polydisulfide propane sulfonate and 3-mercapto-1-propane sulfonic acid in industrial-grade acid copper electroplating solution samples

[0057] Take 100 μL of industrial-grade acid copper electroplating solution, dilute it with deionized water, fix the volume to 10 mL, and analyze it on the machine according to the test conditions of 1). According to the standard curve in step 2), the content of sodium polydisulfide propane sulfonate in the diluted industrial-grade acid copper electroplating solution is 0.1461 mg / L, and sodium 3-mercapto-1-propane sulfonate is not detected.

[0058] Take 3 portions of 1 mL of the diluted industrial-grade acid copper electroplating solution, add 0.05 μg, 0.1 μg, and 2 μg of sodium polydisulfide propane sulfonate and sodium 3-mercapto-1-propane sulfonate standard solutions to each portion, and the calculated recoveries of sodium polydisulfide propane sulfonate are 97.8%, 100.1%, and 114.5%, respectively, and the recoveries of sodium 3-mercapto-1-propane sulfonate are 91.4%, 91.3%, and 90.7%, respectively.

[0059] Comparative Example 1: Investigating the influence of mobile phase on the analysis of mixed standard solution of sodium polydisulfide propane sulfonate and sodium 3-mercapto-1-propane sulfonate

[0060] 1) Test conditions:

[0061] A triple quadrupole high performance liquid chromatography-mass spectrometer equipped with a jet stream electrospray ion source was used as the test instrument.

[0062] Waters CORTECS C18 reverse phase column (2.7um×2.1mm×100mm), column temperature 40°C, flow rate 0.2mL / min, ammonium acetate aqueous solution / acetonitrile as mobile phase, isocratic elution, injection volume 1μL.

[0063] Jet stream electrospray ion source, drying gas temperature 300°C, sheath gas temperature 300°C, drying gas flow rate 5 L / min, sheath gas flow rate 11 L / min, electrospray voltage 45 psi, capillary voltage 4000 V, negative ion scanning, multiple reaction monitoring (MRM).

[0064] 2) The separation of sodium polydisulfide propane sulfonate and sodium 3-mercapto-1-propane sulfonate was investigated at a volume ratio of ammonium acetate aqueous solution (5 mmol / L) / acetonitrile of 90:10 and 95:5, respectively.

[0065] A 1 mg / L mixed standard solution was prepared and analyzed according to the test conditions in 1). It can be concluded that when the volume ratio of ammonium acetate aqueous solution (5 mmol / L) to acetonitrile is 95:5, sodium polydisulfide propane sulfonate and sodium 3-mercapto-1-propane sulfonate can be well separated, while when the volume ratio is 90:10, sodium polydisulfide propane sulfonate and sodium 3-mercapto-1-propane sulfonate cannot be separated. The results are shown in the attached Figure 2 .

[0066] 3) Investigate the separation of sodium polydisulfide propane sulfonate and sodium 3-mercapto-1-propane sulfonate at different ammonium acetate contents. Prepare a 1 mg / L mixed standard solution with an ammonium acetate aqueous solution / acetonitrile volume ratio of 95:5. Perform the analysis on the machine according to the test conditions in 1) and investigate the separation of sodium polydisulfide propane sulfonate and sodium 3-mercapto-1-propane sulfonate when the ammonium acetate content is 2.5, 5, and 10 mmol / L. It can be concluded that when the ammonium acetate content is 5 mmol / L, sodium polydisulfide propane sulfonate and sodium 3-mercapto-1-propane sulfonate are best separated. The results are shown in the attached figure. Figure 3 .

[0067] The above detailed description is a specific description of one feasible embodiment of the present invention. The embodiment is not intended to limit the patent scope of the present invention. Any equivalent implementation or modification that does not deviate from the present invention should be included in the scope of the technical solution of the present invention.

Claims

1. A method for qualitative and quantitative determination of sodium thiopropane sulfonate brightener in an acid copper electroplating solution, wherein the sodium thiopropane sulfonate brightener comprises sodium polydisulfide propane sulfonate and sodium 3-mercapto-1-propane sulfonate, characterized in that: The steps include: (1) dissolving sodium polydisulfide propane sulfonate and sodium 3-mercapto-1-propane sulfonate standard samples in aqueous sulfuric acid to prepare standard solutions of different concentrations, injecting them into a high performance liquid chromatography-mass spectrometer, using ammonium acetate aqueous solution / acetonitrile as the mobile phase, and drawing a standard curve; (2) testing the acid copper electroplating solution under the same testing conditions as step (1), and calculating the contents of sodium polydisulfide propane sulfonate and sodium 3-mercapto-1-propane sulfonate in the acid copper electroplating solution according to a standard curve; Wherein, the concentration of the ammonium acetate aqueous solution in step (1) is 5 mmol / L, and the volume ratio of the ammonium acetate aqueous solution to acetonitrile is 95:5; a Waters CORTECS C18 reverse phase chromatography column is used in step (1); The chromatographic conditions in step (1) are: column temperature 40°C, flow rate 0.2 mL / min, isocratic elution, injection volume 1 μL; The mass spectrometry conditions in step (1) are: jet stream electrospray ion source, drying gas temperature 300°C, sheath gas temperature 300°C, drying gas flow rate 5 L / min, sheath gas flow rate 11 L / min, electrospray voltage 45 psi, capillary voltage 4000 V, negative ion scanning, multiple reaction monitoring MRM; The qualitative and quantitative ion pairs of sodium polydisulfide propane sulfonate are 309 / 154.8; the qualitative and quantitative ion pairs of sodium 3-mercapto-1-propane sulfonate are 155 / 80; The auxiliary qualitative ion pair of sodium polydisulfide propane sulfonate is 309 / 81; the auxiliary qualitative ion pair of sodium 3-mercapto-1-propane sulfonate is 155 / 121.

2. The method according to claim 1, characterized in that The pH of the aqueous sulfuric acid solution in step (1) is 3.5; standard solutions of different concentrations of 0.05 to 2 mg / L are prepared.

3. The method according to claim 1, characterized in that The high performance liquid chromatography-mass spectrometer is a triple quadrupole high performance liquid chromatography-mass spectrometer.

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