Method for detecting contents of Co and Zn elements in Co-Zn double metal cyanide catalyst

Abstract

The invention discloses a method for detecting contents of Co and Zn elements in a Co-Zn double metal cyanide catalyst, and belongs to the technical field of analytical chemistry. The preparation method comprises the steps of sample pretreatment, preparation of a to-be-detected sample solution, preparation of a to-be-detected blank solution, preparation of Co and Zn standard solutions, inductively coupled plasma mass spectrometry detection and the like, the Co-Zn double-metal cyanide catalyst is digested by adopting a specific digestion reagent, so that the Co-Zn double-metal cyanide catalyst is converted into a soluble substance; and detecting and analyzing by adopting an inductively coupled plasma mass spectrometer to obtain the contents of Co and Zn elements. According to the detection method, rapid digestion can be achieved, the risk of the digestion reagent is small, the digestion condition is mild, the content of Co and Zn in the Co-Zn double-metal cyanide catalyst can be accurately detected at the same time, and the problems that in the prior art, the pretreatment time is too long, the process is tedious, and dangerous reagents are used are effectively solved.

Description

Technical Field

[0001] The present invention relates to the technical field of analytical chemistry, and in particular to a method for detecting the contents of Co and Zn elements in a Co-Zn double metal cyanide catalyst. Background Art

[0002] Co-Zn double metal cyanide catalysts (DMC catalysts) are complex complexes based on a double metal cyanide backbone and containing a variety of organic and inorganic ligands. As highly efficient catalysts for epoxy polymerization, DMC catalysts offer products with higher molecular weights and lower unsaturation compared to conventional acid-base catalysts. They have been successfully used in the industrial production of high-molecular-weight, low-unsaturation polyether polyols. The metal content and ratio of DMC catalysts affect catalytic performance, making accurate and rapid determination of the Co and Zn contents in Co-Zn double metal cyanide catalysts particularly important.

[0003] At present, the methods for detecting the element content in the catalyst in the prior art generally include inductively coupled plasma mass spectrometry, inductively coupled plasma atomic emission spectrometry, etc. The sample pretreatment of inductively coupled plasma mass spectrometry and inductively coupled plasma atomic emission spectrometry is generally to use a digestion reagent to convert the water-insoluble sample into a water-soluble inorganic substance, wherein the digestion reagent is generally a strong acid, strong oxidizing system such as concentrated nitric acid, concentrated sulfuric acid, perchloric acid, concentrated hydrochloric acid, and the sample is digested under microwave heating conditions or other heating methods. The above sample pretreatment process takes too long and is cumbersome to operate, and the use of strongly acidic and strongly oxidizing reagents poses a high safety risk. Therefore, it is urgent to invent an analytical method that is simple and safe to operate and can accurately measure the Co and Zn contents in Co-Zn double metal cyanide catalysts. Summary of the Invention

[0004] In order to overcome the shortcomings of the prior art, the purpose of the present invention is to provide a method for detecting the content of Co and Zn elements in a Co-Zn double metal cyanide catalyst. The detection method can achieve rapid digestion, and the digestion reagent has low hazard and mild digestion conditions, and can simultaneously and accurately detect the Co and Zn contents in the Co-Zn double metal cyanide catalyst.

[0005] In order to solve the above problems, the technical solutions adopted by the present invention are as follows: A method for detecting the content of Co and Zn elements in a Co-Zn double metal cyanide catalyst comprises: performing sample pretreatment on the Co-Zn double metal cyanide catalyst using a digestion reagent to convert the catalyst into a soluble substance; and obtaining the content of Co and Zn elements in the Co-Zn double metal cyanide catalyst by inductively coupled plasma mass spectrometry analysis; wherein the digestion reagent is at least one of ethanolamine, diethanolamine, ethylenediamine, diethylenetriamine, and ammonia water.

[0006] As a preferred embodiment of the present invention, the detection method specifically comprises the following steps: S1. Add the Co-Zn double metal cyanide catalyst and the digestion reagent to ultrapure water, sonicate until completely digested, and then add a constant volume reagent to adjust the volume to obtain a sample solution; S2, add internal standard element Ge to the sample solution prepared in step S1, N -Methyl pyrrolidone was added to make the concentration of internal standard element Ge 1-10 μg / mL to obtain the sample solution to be tested; S3, prepare a blank solution to be tested according to the method of steps S1 and S2; S4. Provide Co and Zn element standard solutions with different concentrations and containing 1-10 μg / mL internal standard element Ge; S5. Use an inductively coupled plasma mass spectrometer to detect the sample solution to be tested, the blank solution to be tested, and the standard solutions of Co and Zn elements, respectively, to obtain the signal intensities of the elements to be tested Co and Zn and the internal standard element Ge, and draw a standard curve with the ratio of the signal intensity of the element to be tested to the signal intensity of the internal standard element as the ordinate and the concentration of the element to be tested as the abscissa to obtain the linear regression equation: Co:y1=a1x+b1 Zn:y2=a2x+b2 S6. Process the data according to the standard curve to obtain the concentrations of Co and Zn elements in the sample solution to be tested, and calculate the content of Co and Zn elements in the Co-Zn double metal cyanide catalyst according to the following calculation formula; the calculation formula is: w =( c - c 0)× V × f ÷ m Where, w : Content of the element to be measured in the Co-Zn double metal cyanide catalyst, μg / g; c : Concentration of the element to be tested in the sample solution, μg / mL; c 0: concentration of the element to be measured in the blank solution, μg / mL; V : constant volume, mL; f: dilution multiple; m : Mass of Co-Zn double metal cyanide catalyst, g.

[0007] As a preferred embodiment of the present invention, the mass ratio of the Co-Zn double metal cyanide catalyst, the digestion reagent and the ultrapure water in step S1 is 1:10-50:20-100.

[0008] As a preferred embodiment of the present invention, the volume-fixing reagent in step S1 is composed of ultrapure water, the digestion reagent and N -Methylpyrrolidone according to ultrapure water: Digestion reagent: N -Methyl pyrrolidone = 1:0.1~0.5:0.5~5 in a mass ratio.

[0009] As a preferred embodiment of the present invention, the constant volume in steps S1 and S2 is 50 mL.

[0010] As a preferred embodiment of the present invention, the concentrations of Co and Zn in the standard solution of Co and Zn in step S4 are 0 μg / mL, 1 μg / mL, 2 μg / mL, 4 μg / mL, 8 μg / mL, and 10 μg / mL.

[0011] As a preferred embodiment of the present invention, the inductively coupled plasma mass spectrometer in step S5 is set to an organic injection mode before detection, and the instrument is ensured to operate smoothly and normally.

[0012] As a preferred embodiment of the present invention, the detection power of the inductively coupled plasma mass spectrometer in step S5 is 1300 W, the cooling gas flow rate is 18 L / min, the auxiliary gas flow rate is 1.2 L / min, the carrier gas flow rate is 0.7 L / min, and the oxygen flow rate is 0.035 L / min.

[0013] As a preferred embodiment of the present invention, the detection mode of the inductively coupled plasma mass spectrometer in step S5 is KED mode, the mass number of the Co element is 59, the mass number of the Zn element is 66, and the mass number of the Ge element is 74, and the He collision gas flow rate of the three elements is 4 mL / min.

[0014] Compared with the prior art, the present invention has the following beneficial effects: The detection method provided by the present invention uses an amine digestion reagent to pre-treat a Co-Zn double metal cyanide catalyst, enabling the Co-Zn double metal cyanide catalyst to dissolve in water or other solvents, significantly improving the pre-treatment efficiency of the Co-Zn double metal cyanide catalyst. The treatment time is short, no other complex equipment is required, the digestion conditions are mild, and the risk of the digestion reagent is low. Furthermore, the method is used in conjunction with an inductively coupled plasma mass spectrometer (ICP-MS) for detection, enabling the simultaneous determination of the Co and Zn contents in the Co-Zn double metal cyanide catalyst. It can be seen that the detection method of the present invention is capable of rapid digestion, with a low risk of the digestion reagent and mild digestion conditions, and can simultaneously and accurately detect the Co and Zn contents in the Co-Zn double metal cyanide catalyst. The detection process is simple, rapid, safe, and accurate, effectively resolving the problems of the prior art, such as long pre-treatment time, cumbersome process, and the use of hazardous reagents. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 Schematic diagram of the standard curve of Co and Zn elements obtained in Example 1 of the present invention. DETAILED DESCRIPTION

[0016] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0017] A method for detecting the content of Co and Zn elements in a Co-Zn double metal cyanide catalyst comprises the following steps: S1. Add the Co-Zn double metal cyanide catalyst and the digestion reagent to ultrapure water, ultrasonicate until completely digested, then add the constant volume reagent to 50mL to obtain a sample solution. Wherein, the mass ratio of the Co-Zn double metal cyanide catalyst, the digestion reagent and the ultrapure water is 1:10~50:20~100. The digestion reagent is at least one of ethanolamine, diethanolamine, ethylenediamine, diethylenetriamine and ammonia water. The constant volume reagent is composed of ultrapure water, the above-mentioned digestion reagent and N -Methyl pyrrolidone according to ultrapure water: digestion reagent: N -methyl pyrrolidone = 1:0.1~0.5:0.5~5 in a mass ratio; compared with using water as a solvent, the above-mentioned volume-fixing reagent can obtain a clear and transparent sample solution without removing the organic ligand in the Co-Zn double metal cyanide catalyst, thereby further improving the efficiency of the pretreatment.

[0018] S2, add internal standard element Ge to the sample solution prepared in step S1, N -Methyl pyrrolidone is diluted to 50 mL, so that the concentration of the internal standard element Ge is 1-10 μg / mL to obtain the sample solution to be tested; S3, prepare a blank solution to be tested according to the method of steps S1 and S2; S4. Prepare Co and Zn element standard solutions with concentrations of 0 μg / mL, 1 μg / mL, 2 μg / mL, 4 μg / mL, 8 μg / mL, and 10 μg / mL, and contain 1-10 μg / mL of internal standard element Ge; S5. Set the inductively coupled plasma mass spectrometer to the organic injection mode to ensure the smooth and normal operation of the instrument. Use the inductively coupled plasma mass spectrometer to detect the sample solution to be tested, the blank solution to be tested, and the standard solution of Co and Zn elements respectively. The detection power is 1300W, the cooling gas flow rate is 18L / min, the auxiliary gas flow rate is 1.2L / min, the carrier gas flow rate is 0.7L / min, the oxygen flow rate is 0.035L / min, the detection mode is KED mode, the mass number of the Co element is 59, the mass number of the Zn element is 66, and the mass number of the Ge element is 74. The He collision gas flow rate of the three elements is 4mL / min, and the signal intensity of the elements to be tested Co, Zn and the internal standard element Ge is obtained. Use the signal intensity ratio of the element to be tested to the internal standard element as the vertical coordinate and the concentration of the element to be tested as the horizontal coordinate to draw a standard curve, and obtain the linear regression equation: Co:y1=a1x+b1 Zn:y2=a2x+b2 S6. Process the data according to the standard curve to obtain the concentrations of Co and Zn elements in the sample solution to be tested, and calculate the content of Co and Zn elements in the Co-Zn double metal cyanide catalyst according to the following calculation formula; the calculation formula is: w =( c - c 0)× V × f ÷ m Where, w : Content of the element to be measured in the Co-Zn double metal cyanide catalyst, μg / g; c : Concentration of the element to be tested in the sample solution, μg / mL; c 0: concentration of the element to be measured in the blank solution, μg / mL; V : constant volume, mL; f : dilution multiple; m : Mass of Co-Zn double metal cyanide catalyst, g.

[0019] In order to better illustrate the purpose, technical solutions and advantages of the present invention, the present invention will be further described and explained below in conjunction with specific embodiments, the purpose of which is to understand the contents of the present invention in detail rather than to limit the present invention.

[0020] The raw materials and equipment used in the following examples are all known products and can be prepared by ourselves or purchased from the market. They are mainly as follows: Co-Zn double metal cyanide catalyst (self-made), N Methylpyrrolidone (chromatographic grade), Co standard solution (1000 μg / mL), Zn standard solution (1000 μg / mL), Ge standard solution (1000 μg / mL), ethanolamine (AR), diethanolamine (AR), ethylenediamine, diethylenetriamine, ammonia (GR), and ultrapure water. The mass spectrometer was a Perkin-Elmer inductively coupled plasma mass spectrometer equipped with an organic oxygenation channel (organic injection mode).

[0021] Example 1 A method for detecting the content of Co and Zn elements in a Co-Zn double metal cyanide catalyst comprises the following steps: S1. Sample pretreatment: Weigh about 0.1g of Co-Zn double metal cyanide catalyst and place it in a 50mL centrifuge tube. Add 3g of ethanolamine and 6mL of ultrapure water and digest it completely with ultrasound. Then add the constant volume reagent (ultrapure water: ethanolamine: N -methyl pyrrolidone = 1.5:0.5:3) dilute to 50 mL and shake well to obtain the sample solution.

[0022] S2. Preparation of the sample solution to be tested: 1 mL of the sample solution prepared in step S1 was placed in a 50 mL centrifuge tube, 200 μL of Ge standard solution (1000 μg / mL) was added, and the mixture was stirred for 2 min. N -Methyl pyrrolidone is diluted to 50 mL and shaken to obtain the sample solution to be tested.

[0023] S3. Preparation of blank control solution: Add 3g ethanolamine and 6mL ultrapure water to a 50mL centrifuge tube, and then add the constant volume reagent (ultrapure water: ethanolamine: N 1 mL of the solution was placed in a 50 mL centrifuge tube, and 200 μL of the standard solution (1000 μg / mL) was added. N -Methyl pyrrolidone is diluted to 50 mL and shaken to obtain a blank solution to be tested.

[0024] S4. Preparation of standard solution: prepare 6 50mL centrifuge tubes, draw 0μL, 50μL, 100μL, 200μL, 400μL, 500μL of Co standard solution (1000μg / mL) and Zn standard solution (1000μg / mL) respectively, add 200μL of internal standard element Ge standard solution (1000μg / mL) to each centrifuge tube, use N-Methyl pyrrolidone was used for dilution so that the concentrations of Co and Zn after dilution were 0 μg / mL, 1 μg / mL, 2 μg / mL, 4 μg / mL, 8 μg / mL, and 10 μg / mL, and the concentration of the internal standard element Ge was 4 μg / mL, to obtain a standard solution.

[0025] S5. Then, respectively take the standard solution, the blank solution to be tested, and the sample solution to be tested, and use an inductively coupled plasma mass spectrometer to detect them using inductively coupled plasma mass spectrometry. The test conditions are power 1300W, cooling gas 18L / min, auxiliary gas 1.2L / min, carrier gas 0.7L / min, and oxygen 0.035L / min. The detection mode is KED mode, the mass number of the Co element is 59, the mass number of the Zn element is 66, and the mass number of the Ge element is 74. The collision gas (He) flow rate of the three elements is 4mL / min, and the signal intensity of the elements to be tested Co, Zn, and the internal standard element Ge is obtained. Draw a standard curve with the signal intensity ratio of the element to be tested and the internal standard element as the vertical coordinate and the concentration of the element to be tested as the horizontal coordinate, as shown below: Figure 1 Then the standard curve method calibrated by internal standard method was used for determination and the contents of Co and Zn were calculated.

[0026] The following are the methodological characteristics of this embodiment: 1. Method detection limit and method quantification limit Following the method in step S3, 11 sample blank solutions were prepared and tested for Co and Zn blank values. The instrument detection limits (IDLs) for Co and Zn were calculated. The IDL was 3 times the standard deviation (3SD), and the ILOQ was 10 times the standard deviation (10SD). Based on the sample preparation process and the IDL and ILOQ, the method detection limit (MDL) and method quantification limit (MLQ) were calculated. The results are shown in Table 1.

[0027] The experimental results in Table 1 show that the linear correlation coefficients of cobalt and zinc are greater than 0.999 within the concentration range of 0 to 10 μg / mL, indicating a good linear relationship.

[0028] Table 1 Linear equation, detection limit and quantification limit of cobalt and zinc elements

[0029] 2. Repeatability The samples were tested 5 times in parallel, and the test results were reproducible. The results are shown in Table 2.

[0030] Table 2 Method repeatability

[0031] The results in Table 2 show that this detection method has good repeatability and high accuracy.

[0032] 3. Spike recovery S1. Sample pretreatment: Weigh about 0.1g of Co-Zn double metal cyanide catalyst and place it in a 50mL centrifuge tube. Add 3g of ethanolamine and 6mL of ultrapure water and digest it completely with ultrasound. Then add the constant volume reagent (ultrapure water:ethanolamine: N -methyl pyrrolidone = 1.5:0.5:3) dilute to 50 mL and shake well to obtain the sample solution.

[0033] S2. Preparation of spiked sample solution: 1 mL of the sample solution prepared in step S1 was placed in a 50 mL centrifuge tube, and 200 μL of Ge standard solution (1000 μg / mL), 150 μL of Co standard solution (1000 μg / mL), and 300 μL of Zn standard solution (1000 μg / mL) were added. N -Methyl pyrrolidone was diluted to 50 mL and shaken to obtain the spiked sample solution to be tested.

[0034]

[0035] It has been verified that the Co spike recovery rate of this detection method is between 98.9% and 101.7%, and the Zn spike recovery rate is between 100.2% and 103.4%, which meets the needs of actual production.

[0036] Example 2 This embodiment provides a method for detecting the content of Co and Zn in a Co-Zn double metal cyanide catalyst. The difference between this embodiment and embodiment 1 is only in steps S1 to S3. The rest is the same as embodiment 1, as follows: S1. Sample pretreatment: Weigh about 0.1g of Co-Zn double metal cyanide catalyst and place it in a 50mL centrifuge tube. Add 3mL of ammonia water and 6mL of ultrapure water. Ultrasonic digestion is complete. Add constant volume reagent (ultrapure water: ammonia water: N -methyl pyrrolidone = 1.5:0.5:3) dilute to 50 mL and shake well to obtain the sample solution.

[0037] S2. Preparation of the sample solution to be tested: 1 mL of the sample solution prepared in step S1 was placed in a 50 mL centrifuge tube, 200 μL of Ge standard solution (1000 μg / mL) was added, and the mixture was stirred for 2 min. N -Methyl pyrrolidone is diluted to 50 mL and shaken to obtain the sample solution to be tested.

[0038] S3. Preparation of blank solution to be tested: Add 3 mL of ammonia water and 6 mL of ultrapure water to a 50 mL centrifuge tube, and then add the constant volume reagent (ultrapure water: ammonia water: N-methylpyrrolidone = 1.5:0.5:3) to 50mL, shake well. Take 1mL of this solution and place it in a 50mL centrifuge tube, add 200μL Ge standard solution (1000μg / mL), and N -Methyl pyrrolidone is diluted to 50 mL and shaken to obtain a blank solution to be tested.

[0039] Example 3 This embodiment provides a method for detecting the content of Co and Zn in a Co-Zn double metal cyanide catalyst. The difference between this embodiment and embodiment 1 is only in steps S1 to S3. The rest is the same as embodiment 1, as follows: S1. Sample pretreatment: Weigh about 0.1g of Co-Zn double metal cyanide catalyst and place it in a 50mL centrifuge tube. Add 3mL of diethanolamine and 6mL of ultrapure water. Ultrasonic digestion is complete. Add constant volume reagent (ultrapure water: diethanolamine: N -methyl pyrrolidone = 1.5:0.5:3) dilute to 50 mL and shake well to obtain the sample solution.

[0040] S2. Preparation of the sample solution to be tested: 1 mL of the sample solution prepared in step S1 was placed in a 50 mL centrifuge tube, 200 μL of Ge standard solution (1000 μg / mL) was added, and the mixture was stirred for 2 min. N -Methyl pyrrolidone is diluted to 50 mL and shaken to obtain the sample solution to be tested.

[0041] S3. Preparation of blank solution to be tested: Add 3 mL of diethanolamine and 6 mL of ultrapure water to a 50 mL centrifuge tube, and then add the constant volume reagent (ultrapure water: diethanolamine: N -methylpyrrolidone = 1.5:0.5:3) to 50mL, shake well. Take 1mL of this solution and place it in a 50mL centrifuge tube, add 200μL Ge standard solution (1000μg / mL), and N -Methyl pyrrolidone is diluted to 50 mL and shaken to obtain a blank solution to be tested.

[0042] Example 4 This embodiment provides a method for detecting the content of Co and Zn in a Co-Zn double metal cyanide catalyst. The difference between this embodiment and embodiment 1 is only in steps S1 to S3. The rest is the same as embodiment 1, as follows: S1. Sample pretreatment: Weigh about 0.1g of Co-Zn double metal cyanide catalyst and place it in a 50mL centrifuge tube. Add 3mL of ethylenediamine and 6mL of ultrapure water. Ultrasonic digestion is complete. Add constant volume reagent (ultrapure water: ethylenediamine: N -methyl pyrrolidone = 1.5:0.5:3) dilute to 50 mL and shake well to obtain the sample solution.

[0043] S2. Preparation of the sample solution to be tested: 1 mL of the sample solution prepared in step S1 was placed in a 50 mL centrifuge tube, 200 μL of Ge standard solution (1000 μg / mL) was added, and the mixture was stirred for 2 min. N -Methyl pyrrolidone is diluted to 50 mL and shaken to obtain the sample solution to be tested.

[0044] S3. Preparation of blank solution to be tested: Add 3 mL of ethylenediamine and 6 mL of ultrapure water to a 50 mL centrifuge tube, and then add the constant volume reagent (ultrapure water: ethylenediamine: N -methylpyrrolidone = 1.5:0.5:3) to 50mL, shake well. Take 1mL of this solution and place it in a 50mL centrifuge tube, add 200μL Ge standard solution (1000μg / mL), and N -Methyl pyrrolidone is diluted to 50 mL and shaken to obtain a blank solution to be tested.

[0045] Example 5 This embodiment provides a method for detecting the content of Co and Zn in a Co-Zn double metal cyanide catalyst. The difference between this embodiment and embodiment 1 is only in steps S1 to S3. The rest is the same as embodiment 1, as follows: S1. Sample pretreatment: Weigh about 0.1g of Co-Zn double metal cyanide catalyst and place it in a 50mL centrifuge tube. Add 3mL of diethylenetriamine and 6mL of ultrapure water. Ultrasonic digestion is complete. Add constant volume reagent (ultrapure water: diethylenetriamine: N -methyl pyrrolidone = 1.5:0.5:3) dilute to 50 mL and shake well to obtain the sample solution.

[0046] S2. Preparation of the sample solution to be tested: 1 mL of the sample solution prepared in step S1 was placed in a 50 mL centrifuge tube, 200 μL of Ge standard solution (1000 μg / mL) was added, and the mixture was stirred for 2 min. N -Methyl pyrrolidone is diluted to 50 mL and shaken to obtain the sample solution to be tested.

[0047] S3. Preparation of blank solution to be tested: Add 3 mL of diethylenetriamine and 6 mL of ultrapure water to a 50 mL centrifuge tube, and then add the constant volume reagent (ultrapure water: diethylenetriamine: N -methylpyrrolidone = 1.5:0.5:3) to 50mL, shake well. Take 1mL of this solution and place it in a 50mL centrifuge tube, add 200μL Ge standard solution (1000μg / mL), and N -Methyl pyrrolidone is diluted to 50 mL and shaken to obtain a blank solution to be tested.

[0048] 4. Test results of Examples 1 to 5 The test results of Examples 1 to 5 are shown in Table 3.

[0049] Table 3 Test results of Examples 1 to 5

[0050] As can be seen from Table 3, the test results of Examples 1 to 5 are basically consistent. This shows that using this type of amine reagent as a digestion reagent for Co-Zn double metal cyanide catalysts can obtain relatively reliable results.

[0051] Comparative Example In this comparative example, the Co-Zn double metal cyanide catalyst was pretreated by microwave digestion, and the specific operation was as follows: S1. Prepare 4 digestion tanks, weigh about 0.1g of Co-Zn double metal cyanide catalyst and place it in 3 digestion tanks respectively, and the remaining one is used as a blank tank. Add 5mL of concentrated sulfuric acid and 5mL of concentrated nitric acid to the 4 digestion tanks and let them stand in the fume hood for half an hour. Place the heating plate in the fume hood, place the 4 digestion tanks on the heating plate, and pre-digest at 90℃ for 1 hour. After cooling, add 0.5mL of perchloric acid, cover the lid, place it in the digester, and digest according to the procedure. Heat to 100℃ and digest for 10 minutes; then heat to 150℃ and digest for 20 minutes; finally heat to 190℃ and digest for 20 minutes. After cooling, take out the digestion tank, slowly vent and release the air and pressure in the fume hood, and then open the lid of the digestion tank. Heat to drive out the acid for 1h. After cooling, pour the digestion solution into a 50mL centrifuge tube, rinse the digestion tank with ultrapure water, and then slowly dilute to 50mL with ultrapure water to obtain the sample solution; S2. Take 1 mL of the sample solution prepared in the above steps and place it in a 50 mL centrifuge tube. Add 200 μL of Ge standard solution (1000 μg / mL), dilute to 50 mL with 2% nitric acid solution, and shake well to obtain 1 blank sample solution and 3 sample solutions to be tested.

[0052] S3. Preparation of standard solutions: Prepare 6 50mL centrifuge tubes, draw 0μL, 50μL, 100μL, 200μL, 400μL, and 500μL of Co standard solution (1000μg / mL) and Zn standard solution (1000μg / mL) respectively, add 200μL of internal standard element Ge standard solution (1000μg / mL) to each centrifuge tube, and use 2% nitric acid solution to make up to 50mL. ， The concentrations of Co and Zn were 0 μg / mL, 1 μg / mL, 2 μg / mL, 4 μg / mL, 8 μg / mL, and 10 μg / mL, and the concentration of the internal standard element Ge was 4 μg / mL to obtain standard solutions.

[0053] S4. Since the test solution matrix in the comparative example is an aqueous solution, oxygen is not required to eliminate carbon deposits in the instrument parameters. Other instrument parameters are consistent with those in Example 1. Testing was performed on the instrument. The test results are as follows: Co content is 71038 μg / g, and Zn content is 190545 μg / g.

[0054] By contrast, it can be seen that the embodiments of the present invention and the comparative example are better than the comparative example in the safety of the reagents used. The digestion reagent used in the comparative example has strong acidity, strong oxidizing property, and is corrosive. The reagent safety used in the embodiment is better. The sample pre-treatment of the embodiment can be completed at room temperature, while the comparative example needs to be carried out under the microwave closed heating condition. It can be seen that the digestion conditions of the embodiment are more gentle. The sample pre-treatment time of the embodiment is also faster than that of the comparative example. The time required for the embodiment is about 10 minutes, while the comparative example needs more than 3 hours. For the testing result, there is no significant difference between the embodiment and the comparative example.

[0055] In summary, the detection method of the present invention can achieve rapid digestion, and the digestion reagent has low hazard and mild digestion conditions, and can simultaneously and accurately detect the Co and Zn contents in the Co-Zn double metal cyanide catalyst.

[0056] The above embodiments are only preferred embodiments of the present invention and cannot be used to limit the scope of protection of the present invention. Any non-substantial changes and replacements made by technicians in this field on the basis of the present invention fall within the scope of protection required by the present invention.

Claims

1. A method for detecting the content of Co and Zn elements in a Co-Zn double metal cyanide catalyst, characterized in that: A digestion reagent is used to pre-treat a Co-Zn double metal cyanide catalyst sample to convert it into a soluble substance, and the Co and Zn element contents in the Co-Zn double metal cyanide catalyst are analyzed by inductively coupled plasma mass spectrometry; wherein the digestion reagent is at least one of ethanolamine, diethanolamine, ethylenediamine, diethylenetriamine, and ammonia water.

2. The method for detecting the content of Co and Zn elements in the Co-Zn double metal cyanide catalyst according to claim 1, wherein: The specific steps include: S1. Add the Co-Zn double metal cyanide catalyst and the digestion reagent to ultrapure water, perform ultrasonication until complete digestion, and then add a constant volume reagent to adjust the volume to obtain a sample solution; S2, add internal standard element Ge to the sample solution prepared in step S1, N -Methyl pyrrolidone was added to make the concentration of internal standard element Ge 1-10 μg / mL to obtain the sample solution to be tested; S3, prepare a blank solution to be tested according to the method of steps S1 and S2; S4. Provide Co and Zn element standard solutions with different concentrations and containing 1-10 μg / mL internal standard element Ge; S5. Use an inductively coupled plasma mass spectrometer to detect the sample solution to be tested, the blank solution to be tested, and the standard solutions of Co and Zn elements, respectively, to obtain the signal intensities of the elements to be tested Co and Zn and the internal standard element Ge, and draw a standard curve with the ratio of the signal intensity of the element to be tested to the signal intensity of the internal standard element as the ordinate and the concentration of the element to be tested as the abscissa to obtain the linear regression equation: Co:y1=a1x+b1 Zn:y2=a2x+b2 S6. Process the data according to the standard curve to obtain the concentrations of Co and Zn elements in the sample solution to be tested, and calculate the content of Co and Zn elements in the Co-Zn double metal cyanide catalyst according to the following calculation formula; the calculation formula is: w =( c - c 0)× V × f ÷ m Where, w : Content of the element to be measured in the Co-Zn double metal cyanide catalyst, μg / g; c : Concentration of the element to be tested in the sample solution, μg / mL; c 0: concentration of the element to be measured in the blank solution, μg / mL; V : constant volume, mL; f : dilution multiple; m : Mass of Co-Zn double metal cyanide catalyst, g.

3. The method for detecting the content of Co and Zn elements in the Co-Zn double metal cyanide catalyst according to claim 2, characterized in that: The mass ratio of the Co-Zn double metal cyanide catalyst, the digestion reagent and the ultrapure water in step S1 is 1:10~50:20~100.

4. The method for detecting the content of Co and Zn elements in the Co-Zn double metal cyanide catalyst according to claim 2, wherein: The constant volume reagent in step S1 is composed of ultrapure water, the digestion reagent and N -Methyl pyrrolidone according to ultrapure water: digestion reagent: N -Methyl pyrrolidone = 1:0.1~0.5:0.5~5 in a mass ratio.

5. The method for detecting the content of Co and Zn elements in the Co-Zn double metal cyanide catalyst according to claim 2, characterized in that: The fixed volume in steps S1 and S2 is 50 mL.

6. The method for detecting the content of Co and Zn elements in the Co-Zn double metal cyanide catalyst according to claim 2, characterized in that: The Co and Zn element concentrations of the Co and Zn element standard solutions in step S4 are 0 μg / mL, 1 μg / mL, 2 μg / mL, 4 μg / mL, 8 μg / mL, and 10 μg / mL.

7. The method for detecting the content of Co and Zn elements in the Co-Zn double metal cyanide catalyst according to claim 2, characterized in that: The detection power of the inductively coupled plasma mass spectrometer in step S5 is 1300 W, the cooling gas flow rate is 18 L / min, the auxiliary gas flow rate is 1.2 L / min, the carrier gas flow rate is 0.7 L / min, and the oxygen flow rate is 0.035 L / min.

8. The method for detecting the content of Co and Zn elements in the Co-Zn double metal cyanide catalyst according to claim 2, characterized in that: The detection mode of the inductively coupled plasma mass spectrometer in step S5 is KED mode, the mass number of the Co element is 59, the mass number of the Zn element is 66, and the mass number of the Ge element is 74, and the He collision gas flow rate of the three elements is 4 mL / min.

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