Method for measuring content of sodium diisobutyl dithiophosphinate by high performance liquid chromatography

Abstract

The invention belongs to the field of chemical detection and analysis, and particularly relates to a method for determining the content of sodium diisobutyl dithiophosphinate by using high performance liquid chromatography. According to the method, a C18 reversed-phase chromatographic column is adopted as a chromatographic column, an ultraviolet detector is adopted as a detector, a 20-30 mmol / L ammonium acetate aqueous solution is adopted as a mobile phase A, acetonitrile is adopted as a mobile phase B, a specific gradient elution procedure is adopted, and the content of sodium diisobutyl dithiophosphinate is separated and measured. According to the method, the sodium diisobutyl dithiophosphinate and the impurities thereof can be effectively separated, the content of the sodium diisobutyl dithiophosphinate can be rapidly and accurately measured by adopting the method, and a new solution thought is provided for the problems of purity detection and impurity control in the production of the sodium diisobutyl dithiophosphinate.

Description

Technical Field

[0001] This invention relates to the field of chemical testing and analysis, and in particular to a method for determining the content of sodium diisobutyldithiophosphonate in a reaction solution by high performance liquid chromatography. Background Technology

[0002] Sodium diisobutyldithiophosphonate is a novel and highly efficient collector for sulfide ores such as gold, silver, copper, and lead-zinc ores. It also has weak foaming properties and a special separation effect on difficult-to-process polymetallic ores.

[0003] Currently, there are no national or industry standards for sodium diisobutyldithiophosphonate (DIPS). While domestic production capacity for DIPS is increasing, an effective method for content detection remains lacking. In enterprise standard Q / JXHG 001—2022 for DIPS, phosphorus content is determined by the quinoline phosphomolybdate gravimetric method, and the DIPS content in the product is then calculated based on the phosphorus content. However, this method is complex, time-consuming, and susceptible to interference from impurities such as phosphorus-containing raw materials. Summary of the Invention

[0004] To address the aforementioned issues, the liquid chromatography method provided by this invention can rapidly separate sodium diisobutyldithiophosphonate and accurately determine its content, providing timely and accurate data guidance for adjusting the production process parameters of sodium diisobutyldithiophosphonate.

[0005] A method for determining the content of sodium diisobutyldithiophosphonate by high performance liquid chromatography (HPLC) is disclosed, using an HPLC instrument under the following chromatographic conditions: Mobile phase A is an aqueous solution of ammonium acetate, and mobile phase B is acetonitrile; The elution program is gradient elution, and the initial volume ratio of mobile phase A to mobile phase B is (5-15):(95-85).

[0006] Furthermore, the gradient elution procedure specifically includes: During the 0-2 min period, the volume ratio of mobile phase A to mobile phase B was (5-15):(95-85). During the 2-9 min interval, the volume ratio of mobile phase A to mobile phase B gradually increased from (5-15):(95-85) to (95-85):(5-15). At 9-12 min, the volume ratio of mobile phase A to mobile phase B is (95-85):(5-15). At 12-12.1 min, the volume ratio of mobile phase A to mobile phase B decreased from (95-85):(5-15) to (5-15):(95-85). At 12.1-15 min, the volume ratio of mobile phase A to mobile phase B is (5-15):(95-85).

[0007] Furthermore, the chromatographic column is a silica-based column.

[0008] Furthermore, the chromatographic column is a C18 column with dimensions of 4.6 × 250 mm and 5 μm.

[0009] Furthermore, the flow rate is 0.8-1.2 mL / min, preferably 1.0 mL / min.

[0010] Furthermore, the column temperature is 28-32℃, preferably 30℃.

[0011] Furthermore, in the mobile phase A, the concentration of the ammonium acetate aqueous solution is 20-30 mmol / L, preferably 25 mmol / L.

[0012] Furthermore, the injection volume is 5-20 μL, preferably 10 μL.

[0013] Furthermore, the ultraviolet detection wavelength is 235-245 nm, preferably 240 nm.

[0014] Furthermore, the determination method includes the following steps: (1) Prepare standard solutions of sodium diisobutyl dithiophosphonate of different concentrations using mobile phase A as solvent; (2) Inject the standard solutions prepared in step (1) sequentially for liquid phase analysis, and establish a standard curve based on the concentration of the standard solutions and the corresponding peak areas; (3) Prepare the sample solution to be tested. Inject the blank solution and the sample solution to be tested sequentially using the same method as in step (2). Calculate the content of each substance to be tested according to the external standard method. Furthermore, the concentration of the sodium diisobutyldithiophosphonate standard solution is 100–1000 mg / L; the standard curve equation is y = 12712x - 1546.5, and the correlation coefficient is 0.9994.

[0015] The beneficial effects of this invention are as follows: 1. In this invention, ammonium acetate aqueous solution is used to adjust the pH, sodium diisobutyl dithiophosphonate has good separation, fast peak elution time, and good peak shape.

[0016] 2. This invention uses liquid chromatography and a specific gradient elution program to quickly and accurately separate impurities and sodium diisobutyldithiophosphonate and accurately determine their content. The test can be completed within 15 minutes, which greatly shortens the detection time, improves work efficiency, and enables real-time monitoring of the synthesis reaction.

[0017] 3. This method is simple to operate, highly accurate, and has good precision. Attached Figure Description

[0018] Figure 1 The standard curve of sodium diisobutyl dithiophosphonate obtained in Example 1.

[0019] Figure 2 The test spectrum of the sodium diisobutyl dithiophosphonate standard sample obtained in Example 1.

[0020] Figure 3 The test spectrum of sodium diisobutyl dithiophosphonate obtained in Example 1.

[0021] Figure 4 Example 3: Gradient elution (initial mobile phase ratio A:B=30:70) test spectrum of the sample.

[0022] Figure 5 Comparative Example 1: Isocratic elution (mobile phase A:B = 20:80) Spectrum of the test sample. Detailed Implementation

[0023] The embodiments of the present invention will be described in detail below with reference to the examples. The following examples are only used to illustrate the present invention and should not be regarded as limiting the scope of the present invention.

[0024] The instrument used in this invention is a WatersAlliance E2695 high-performance liquid chromatograph. The chromatographic column was an Agilent ZORBAX Eclipse Plus C18, 4.6 × 250 mm, 5 μm.

[0025] The sodium diisobutyl dithiophosphonate sample selected for testing was a self-produced product of our company, with a content of approximately 50%. The sodium diisobutyl dithiophosphonate standard sample selected was a self-purchased product with a purity of 99.0%.

[0026] Example 1 A method for determining the content of sodium diisobutyldithiophosphonate by high performance liquid chromatography includes the following steps: (1) Chromatographic conditions Flow rate: 1.0 mL / min.

[0027] Column temperature: 30℃.

[0028] Ultraviolet detection wavelength: 240 nm.

[0029] Injection volume: 10 μL.

[0030] Mobile phase A is a 25 mmol / L ammonium acetate aqueous solution, and mobile phase B is acetonitrile. The gradient elution program is shown in Table 1 below: Table 1

[0031] In Table 1, the contents of mobile phase A and mobile phase B are volume contents; during the period of 2-9 min, the volume ratio of mobile phase A:B increased uniformly from 10:90 to 90:10; during the period of 12-12.1 min, the volume ratio of mobile phase A:B decreased uniformly from 90:10 to 10:90.

[0032] (2) Establishment of the standard curve Weigh 0.1010 g of sodium diisobutyldithiophosphonate standard, use mobile phase A solution as solvent, make up to 100 mL, and then dilute stepwise to prepare standard solutions with concentrations of 100, 200, 400, 600, 800, and 1000 ug / mL. After powering on the instrument and allowing it to stabilize, inject the prepared standard solutions sequentially for liquid chromatography analysis. Establish a standard curve with the concentration of the standard solution on the x-axis and the corresponding peak area on the y-axis. The standard curve equation is y = 12712x - 1546.5, with a correlation coefficient of 0.9994. The standard curve and spectrum are shown below. Figure 1 and Figure 2 The retention time of sodium diisobutyl dithiophosphonate is approximately 5.54 min.

[0033] (3) Sample determination Weigh 0.1–0.2 g (accurate to 0.0002 g) of the test sample into a 100 mL volumetric flask, add mobile phase A solution to dissolve the sample, bring the volume to the mark, sonicate for 10 min, cool to room temperature, and shake well before use.

[0034] Inject the blank solution and the sample solution to be tested sequentially. Calculate the content of each analyte based on the standard curve. See the spectrum. Figure 3 .

[0035] Example 2 The method for determining the content of sodium diisobutyldithiophosphonate provided in Example 1 was validated as follows: (1) Limit of detection and limit of quantitation The standard solution was diluted to a lower concentration and tested under the chromatographic conditions of Example 1. The limit of detection (LOD) was the concentration at which the signal-to-noise ratio (S / N) was approximately 3, and the limit of quantitation (LOQ) was four times the LOD. Calculations showed that the LOD for sodium diisobutyldithiophosphonate was 0.1454 ug / mL, and the LOQ was 0.5816 ug / mL.

[0036] (2) Repeatability and precision tests The standard solution (concentration of approximately 100 ug / mL) was tested under the chromatographic conditions described in Example 1. The results were measured seven times consecutively, and the results are shown in Table 2 below. The RSD was 0.64%, indicating that the test results had good repeatability and precision.

[0037] Table 2 Precision Test

[0038] (3) Spike recovery test To further verify the feasibility of the method, a spiked recovery test was conducted. The test sample was analyzed under the chromatographic conditions described in Example 1. Low, medium, and high spiked recovery tests were performed on the standard solution, with three parallel determinations at each level. The spiked recovery rate was calculated using the formula: H = (X...) 加标后 -X 加标前 ) / X 加标量 The spiked recovery rate was calculated as ×100%. As shown in Table 3, the recovery rate of sodium diisobutyldithiophosphonate was 94.2%–103.2%, which is a suitable range and meets the experimental requirements.

[0039] Table 3 Recovery Rate Test

[0040] As can be seen from the above data, the method of the present invention can quickly and accurately separate and determine the content of sodium diisobutyldithiophosphonate, and the determination results have good repeatability and precision, and good accuracy.

[0041] Example 3 Example 3-1: The method and conditions are the same as in Example 1, except that during the detection process, the elution method is gradient elution. From 0 to 2 min, the volume ratio of mobile phase A to mobile phase B is 5:95; from 2 to 9 min, the volume ratio of mobile phase A to mobile phase B gradually increases from 5:95 to 95:5; from 9 to 12 min, the volume ratio of mobile phase A to mobile phase B is 95:5; from 12 to 12.1 min, the volume ratio of mobile phase A to mobile phase B decreases from 95:5 to 5:95; from 12.1 to 15 min, the volume ratio of mobile phase A to mobile phase B is 5:95.

[0042] Example 3-2: The method and conditions are the same as in Example 1, except that during the detection process, the elution method is gradient elution. From 0 to 2 min, the volume ratio of mobile phase A to mobile phase B is 15:85; from 2 to 9 min, the volume ratio of mobile phase A to mobile phase B gradually increases from 15:85 to 85:15; from 9 to 12 min, the volume ratio of mobile phase A to mobile phase B is 85:15; from 12 to 12.1 min, the volume ratio of mobile phase A to mobile phase B decreases from 85:15 to 15:85; from 12.1 to 15 min, the volume ratio of mobile phase A to mobile phase B is 15:85.

[0043] Example 3-3: The method and conditions are the same as in Example 1, except that during the detection process, the elution method is gradient elution. From 0 to 2 min, the volume ratio of mobile phase A to mobile phase B is 20:80; from 2 to 9 min, the volume ratio of mobile phase A to mobile phase B gradually increases from 20:80 to 80:20; from 9 to 12 min, the volume ratio of mobile phase A to mobile phase B is 80:20; from 12 to 12.1 min, the volume ratio of mobile phase A to mobile phase B decreases from 80:20 to 20:80; from 12.1 to 15 min, the volume ratio of mobile phase A to mobile phase B is 20:80.

[0044] Examples 3-4: The methods and conditions are the same as in Example 1, except that during the detection process, the elution method is gradient elution. From 0 to 2 min, the volume ratio of mobile phase A to mobile phase B is 25:75; from 2 to 9 min, the volume ratio of mobile phase A to mobile phase B gradually increases from 25:75 to 75:25; from 9 to 12 min, the volume ratio of mobile phase A to mobile phase B is 75:25; from 12 to 12.1 min, the volume ratio of mobile phase A to mobile phase B decreases from 75:25 to 25:75; from 12.1 to 15 min, the volume ratio of mobile phase A to mobile phase B is 25:75.

[0045] Examples 3-5: The methods and conditions are the same as in Example 1, except that during the detection process, the elution method is gradient elution. From 0 to 2 min, the volume ratio of mobile phase A to mobile phase B is 30:70; from 2 to 9 min, the volume ratio of mobile phase A to mobile phase B gradually increases from 30:70 to 70:30; from 9 to 12 min, the volume ratio of mobile phase A to mobile phase B is 70:30; from 12 to 12.1 min, the volume ratio of mobile phase A to mobile phase B decreases from 70:30 to 30:70; from 12.1 to 15 min, the volume ratio of mobile phase A to mobile phase B is 30:70.

[0046] The standard sample provided in Example 1 was tested, and the test results of Examples 3-5 are as follows: Figure 4The retention time results of Examples 3-1 to 3-5 are shown in Table 4 below. As the proportion of mobile phase A increases, the retention time increases significantly, and the chromatogram baseline fluctuates slightly, but the impact on the results is small. The experimental results show that when using gradient elution, the initial ratio of mobile phase A to mobile phase B is (5-15): (95-85), which allows for faster peak elution while maintaining good separation between the product and impurities, and is therefore the preferred choice.

[0047] Table 4 Results of investigation of different mobile phases in Comparative Example 2

[0048] Comparative Example 1 Comparative Example 1-1 uses the same method and conditions as Example 1, except that during the detection process, the elution method is isocratic elution, and the ratio of mobile phase A to mobile phase B is 20:80. Comparative Examples 1-2 used the same methods and conditions as Example 1, except that during the detection process, the elution method was isocratic elution, and the ratio of mobile phase A to mobile phase B was 40:60. Comparative Examples 1-3 used the same methods and conditions as Example 1, except that during the detection process, the elution method was isocratic elution, and the ratio of mobile phase A to mobile phase B was 60:40. Comparative Examples 1-4 used the same methods and conditions as Example 1, except that during the detection process, the elution method was isocratic elution, and the ratio of mobile phase A to mobile phase B was 80:20. The standard provided in Example 1 was tested, and the results showed that when the proportion of mobile phase B (organic phase) in Comparative Example 1-1 was high, the peak elution time was fast, but it could not be separated from the impurity peaks. Figure 5 In Comparative Examples 1-2 and 1-3, when the ratios of mobile phase A and mobile phase B were not significantly different, the separation of sodium diisobutyldithiophosphonate from impurities was poor. In Comparative Example 1-4, when the ratio of mobile phase A to mobile phase B was 80:20, sodium diisobutyldithiophosphonate did not produce a peak for a short period. These results indicate that isocratic elution cannot rapidly and effectively separate sodium diisobutyldithiophosphonate from impurities.

[0049] As can be seen from the results of the above examples and comparative examples, the ammonium acetate aqueous solution and acetonitrile mobile phase used in this invention, under a specific gradient elution program, can solve the problem of complete separation of sodium diisobutyl dithiophosphonate from impurities and rapid determination of its content.

Claims

1. A method for determining the content of sodium diisobutyldithiophosphonate by high performance liquid chromatography, characterized in that, The determination was performed using a high-performance liquid chromatograph (HPLC) under the following chromatographic conditions: Mobile phase A is an aqueous solution of ammonium acetate, and mobile phase B is acetonitrile; The elution program is gradient elution, and the initial volume ratio of mobile phase A to mobile phase B is (5-15):(95-85).

2. The method for determining the content of sodium diisobutyldithiophosphonate by high performance liquid chromatography according to claim 1, characterized in that, The gradient elution procedure is as follows: During the 0-2 min period, the volume ratio of mobile phase A to mobile phase B was (5-15):(95-85). During the 2-9 min interval, the volume ratio of mobile phase A to mobile phase B gradually increased from (5-15):(95-85) to (95-85):(5-15). At 9-12 min, the volume ratio of mobile phase A to mobile phase B is (95-85):(5-15). At 12-12.1 min, the volume ratio of mobile phase A to mobile phase B decreased from (95-85):(5-15) to (5-15):(95-85). At 12.1-15 min, the volume ratio of mobile phase A to mobile phase B is (5-15):(95-85).

3. The method for determining the content of sodium diisobutyldithiophosphonate by high performance liquid chromatography according to claim 1, characterized in that, The chromatographic column is a silica-based column.

4. The method for determining the content of sodium diisobutyldithiophosphonate by high performance liquid chromatography according to claim 1, characterized in that, The chromatographic column is a C18 column with dimensions of 4.6 × 250 mm and a diameter of 5 μm.

5. The method for determining the content of sodium diisobutyldithiophosphonate by high performance liquid chromatography according to claim 1, characterized in that, The flow rate is 0.8-1.2 mL / min, preferably 1.0 mL / min.

6. The method for determining the content of sodium diisobutyldithiophosphonate by high performance liquid chromatography according to claim 1, characterized in that, Column temperature: 28-32℃, preferably 30℃.

7. The method for determining the content of sodium diisobutyldithiophosphonate by high performance liquid chromatography according to claim 1, characterized in that, In the mobile phase A, the concentration of the ammonium acetate aqueous solution is 20-30 mmol / L, preferably 25 mmol / L.

8. The method for determining the content of sodium diisobutyldithiophosphonate by high performance liquid chromatography according to claim 1, characterized in that, The injection volume is 5-20 μL, preferably 10 μL.

9. The method for determining the content of sodium diisobutyldithiophosphonate by high performance liquid chromatography according to claim 1, characterized in that, Ultraviolet detection wavelength: 235-245nm, preferably 240nm.

10. The method for determining the content of sodium diisobutyldithiophosphonate by high performance liquid chromatography according to claim 1, characterized in that, Includes the following steps: (1) Prepare standard solutions of sodium diisobutyl dithiophosphonate of different concentrations using mobile phase A as solvent; (2) Inject the standard solutions prepared in step (1) sequentially for liquid phase analysis, and establish a standard curve based on the concentration of the standard solutions and the corresponding peak areas; (3) Prepare the sample solution to be tested. Inject the blank solution and the sample solution to be tested sequentially using the same method as in step (2). Calculate the content of each substance to be tested according to the external standard method. The concentration of the sodium diisobutyl dithiophosphonate standard solution is 100–1000 mg / L; the standard curve equation is y = 12712x - 1546.5, and the correlation coefficient is 0.9994.

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