Method for determining residual sodium and potassium elements in sucrose octasulfate triethylamine

Abstract

The invention provides a method for determining potassium element and sodium element in sucrose octasulfate triethylamine by microwave digestion-inductively coupled plasma mass spectrometry, which adopts a mixed system of acetonitrile and perchloric acid in a specific ratio to perform microwave digestion on sucrose octasulfate triethylamine, and the whole process is performed in a closed environment. It is guaranteed that the sample is completely dissolved, and the possibility that the sample is polluted in the pretreatment process is effectively reduced; meanwhile, in ICP-MS instrument measurement of a test solution, interference is eliminated by adopting a collision reaction tank method, an internal standard solution is added on line, the working condition of the instrument is optimized, and the method has the advantages of low detection limit, stability, accuracy, rapidness and the like, and has extremely high application value.

Description

Technical Field

[0001] The invention belongs to the technical field of biomedicine, and particularly relates to a method for determining residual potassium and sodium elements in sucrose octasulfate triethylamine by microwave digestion-inductively coupled plasma mass spectrometry. Background Art

[0002] Sucrose octasulfate triethylamine is a white crystalline powder that is soluble in water and alcohol solvents. It has good surface activity and emulsifying ability, and can effectively reduce the surface tension of the liquid surface. Sucrose octasulfate triethylamine is widely used in chemical laboratories as a solvent and colloid stabilizer for ion electrophoresis determination of protein and nucleic acid molecular weight. It is also used in detergents, surfactants, emulsifiers, lubricants and dye industries.

[0003] Sucrose octasulfate triethylamine is prone to cause potassium and sodium elements to remain in the sample during use, resulting in elemental contamination. Therefore, the accurate determination of residual sodium and potassium elements in the product after using sucrose octasulfate triethylamine can be used to determine whether the sample is contaminated during the pretreatment process.

[0004] In the existing technology, there are many methods for the analysis and testing of potassium and sodium elements. Traditional elemental analysis methods include spectrophotometry, atomic absorption (flame and graphite furnace), atomic fluorescence spectrometry, inductively coupled plasma atomic emission spectrometry, etc. These methods have their own advantages, but also have their limitations, such as: complex sample pretreatment, requiring extraction, concentration, enrichment, etc.; inability to detect multiple components and multiple elements simultaneously, which is time-consuming and labor-intensive; the detection limit or sensitivity of the instrument does not meet the index requirements, etc. Summary of the invention

[0005] In order to overcome the defects of the prior art, the present invention provides the following technical solutions: The first aspect of the present invention discloses a method for determining the potassium and sodium residues in sucrose octasulfate triethylamine by microwave digestion-inductively coupled plasma mass spectrometry, comprising the following steps: S1: Weigh a solid sample to be tested, place it in a digestion tank, add 99.95wt% acetonitrile and 70-72wt% perchloric acid in sequence, seal it and put it into a microwave digestion instrument, and heat and digest for 20-30min, wherein the volume ratio of acetonitrile to perchloric acid is 1-5:1; S2: After digestion, cool, add an appropriate amount of 7~13v / v% nitric acid, and transfer to a volumetric flask to obtain the test solution; S3: Prepare a series of standard working solutions containing the elements to be tested, test them using inductively coupled plasma mass spectrometry, draw a standard curve, and fit a linear equation. The concentrations of the standard working solutions prepared for drawing the standard curve are 0 μ g / L, 50 μ g / L, 100 μ g / L, 200 μ g / L, 400 μ g / L and 1000 μ g / L; S4: The test solution obtained in S2 is introduced into the inductively coupled plasma mass spectrometer through the injection system, and the standard mode combined with the collision reaction cell method and the online addition of the internal standard method are used for quantitative inductively coupled plasma mass spectrometry determination, and the content of the element to be measured is determined according to the standard curve.

[0006] Preferably, the grade of acetonitrile in S1 is chromatographic grade.

[0007] Preferably, the perchloric acid concentration in S1 is 71 wt %.

[0008] Preferably, the volume ratio of acetonitrile to perchloric acid in S1 is 3:1.

[0009] Preferably, the nitric acid concentration in S2 is 10 v / v%.

[0010] Preferably, the microwave digestion procedure described in S1 is: using a power of 800 W, heating to 160° C. within 15 minutes, then cooling to 35° C. within 10 minutes and then stopping the procedure.

[0011] Preferably, in S3, the operating parameters of the inductively coupled plasma mass spectrometer are: injection time is 45s, flushing time is 50s, interval is 0.05s, nebulizing gas flow rate is 1.04L / min, nebulizing pool temperature is 2.9°C, nebulizing gas is argon, repeated measurement / times is 3, channel is 1, peristaltic pump speed is 60.0rpm, collision gas flow rate is 4.0mL / min, collision gas is helium, and cooling gas is argon.

[0012] Preferably, in S4, the test liquid is introduced into the inductively coupled plasma mass spectrometer through the sampling system, the standard mode is combined with the collision reaction cell method, the isotope of the metal element is selected, and the working parameters of the inductively coupled plasma mass spectrometer are set to 72 Ge was used as the internal standard, and the online internal standard addition method was used for quantitative inductively coupled plasma mass spectrometry, and the content of the element to be measured was determined according to the standard curve; the isotopes of potassium and sodium are 39 K and 23 Nah.

[0013] The second aspect of the present invention discloses the application of the above method in determining the content of potassium and sodium elements.

[0014] Compared with other analytical testing techniques, inductively coupled plasma mass spectrometry (ICP-MS) has the characteristics of high sensitivity, wide linear range, simultaneous determination of multiple elements, simple spectral lines, and low background interference. Compared with the prior art, the present invention has the following technical effects: 1. There are the following difficulties in detecting the potassium and sodium residues in sucrose octasulfate triethylamine: potassium and sodium are widely present in nature and are prone to elemental contamination. At the same time, sucrose octasulfate triethylamine is a difficult to dissolve sample. The present invention adopts a specific ratio of acetonitrile and perchloric acid mixed system to perform microwave digestion on sucrose octasulfate triethylamine, and the whole process is carried out in a closed environment, which ensures that the sample is completely digested and effectively reduces the possibility of the sample being contaminated during the pre-treatment process.

[0015] 2. Potassium and sodium in sucrose octasulfate triethylamine are trace elements. If you want to detect them completely, you need to use a highly sensitive instrument. In the ICP-MS instrument determination of the sample digestion solution, the internal standard solution is added online and the collision reaction pool method is adopted to eliminate interference, and the instrument working conditions are optimized. The detection limits of potassium and sodium in the method reach 15.007ppb and 3.046ppb respectively, and the linear correlation coefficients reach 1.000. The recovery rate is between 104.3% and 113.7%. It has the advantages of stability, low detection limit, rapidity, accuracy, etc. The present invention has a strong application value. DETAILED DESCRIPTION

[0016] The present invention is further described below by way of examples, but the present invention is not limited to the scope of the examples. The experimental methods in the following examples, unless otherwise specified, are conventional methods, and are performed according to the techniques or conditions described in the literature in the art or according to the product instructions. The materials, reagents, etc. used in the following examples, unless otherwise specified, can all be obtained from commercial sources.

[0017] Example 1 A method for determining potassium and sodium residues in sucrose octasulfate triethylamine by microwave digestion-inductively coupled plasma mass spectrometry comprises the following steps: 1.1 Experimental instruments and utensils Inductively coupled plasma mass spectrometer: iCAP TQs ICP-MS from Thermo Corporation, USA; Ultrapure water system: resistivity 18.2 MΩ·cm, Milli-Q Element A10 from Millipore, USA; Microwave digestion instrument: Shanghai Xinyi MDS-6G; 50mL FEP volumetric flask, 100mL FEP volumetric flask, 1000mL FEP volumetric flask, 10mL FEP measuring cylinder, 100mL FEP beaker, rinse repeatedly with ultrapure water 3-5 times.

[0018] 1.2 Experimental Reagents Ultrapure water, deionized water purified by Milli-Q Element A10 system; 69wt% nitric acid (superior grade) and 71wt% perchloric acid (superior grade) are commercially available reagents; Potassium element standard solution (National Nonferrous Metals and Electronic Materials Testing Center), Sodium element standard solution (National Nonferrous Metals and Electronic Materials Testing Center), Germanium element standard solution (National Nonferrous Metals and Electronic Materials Testing Center).

[0019] 1.3 Analysis methods

[0020] (1) Accurately weigh 50 mg of sucrose octasulfate triethylamine sample, place it in a polytetrafluoroethylene digestion tank, add 4 mL of perchloric acid, seal it and place it in a microwave digestion instrument, and heat and digest it for 25 minutes according to a pre-set microwave digestion program. The microwave digestion program described in step (1) is: use a power of 800 W, heat up, heat to 160° C. within 15 minutes, then cool down, and stop the program after the temperature drops to 35° C. within 10 minutes; (2) After digestion, cool the mixture, add an appropriate amount of 10 v / v% nitric acid, transfer the mixture to a volumetric flask and dilute to volume with 10 v / v% nitric acid to obtain a test solution; (3) Prepare a series of standard working solutions containing the elements to be tested, test them using inductively coupled plasma mass spectrometry, draw a standard curve, and fit a linear equation. The concentrations of the standard working solutions prepared for drawing the standard curve are 0 μ g / L, 50 μ g / L, 100 μ g / L, 200 μ g / L, 400 μ g / L and 1000 μ g / L; (4) introducing the test solution obtained in steps (2) and (3) into an inductively coupled plasma mass spectrometer through a sampling system, and selecting the isotope of the metal element by combining the standard mode with the collision reaction cell method. 39 K and 23 Na, set the operating parameters of the inductively coupled plasma mass spectrometer to 72Ge is used as the internal standard, and the inductively coupled plasma mass spectrometry is carried out quantitatively by online addition of the internal standard method, and the content of the element to be measured is determined according to the standard curve; preferably, the isotope of the metal element is 39 K and 23 Na, wherein, in step (3), the operating parameters of the inductively coupled plasma mass spectrometer are: injection time is 45s, flushing time is 50s, interval is 0.05s, nebulizing gas flow rate is 1.04L / min, nebulizing pool temperature is 2.9°C, nebulizing gas is argon, repeated measurement / times is 3, channel is 1, peristaltic pump speed is 60.0rpm, collision gas flow rate is 4.0mL / min, collision gas is helium, and cooling gas is argon.

[0021] The sample was not completely dissolved during the microwave digestion process, and the potassium and sodium contents in the sample were determined to be 0.058 ppb and 0.032 ppb, respectively.

[0022] Example 2 A method for determining potassium and sodium residues in sucrose octasulfate triethylamine by microwave digestion-inductively coupled plasma mass spectrometry comprises the following steps: 1.1 Experimental instruments and utensils Inductively coupled plasma mass spectrometer: iCAP TQs ICP-MS from Thermo Corporation, USA; Ultrapure water system: resistivity 18.2 MΩ·cm, Milli-Q Element A10 from Millipore, USA; Microwave digestion instrument: Shanghai Xinyi MDS-6G; 50mL FEP volumetric flask, 100mL FEP volumetric flask, 1000mL FEP volumetric flask, 10mL FEP measuring cylinder, 100mL FEP beaker, rinse repeatedly with ultrapure water 3-5 times.

[0023] 1.2 Experimental Reagents Ultrapure water, deionized water purified by Milli-Q Element A10 system; 69wt% nitric acid (superior purity) and 99.95wt% acetonitrile (chromatographic grade) are commercially available reagents; Potassium element standard solution (National Nonferrous Metals and Electronic Materials Testing Center), Sodium element standard solution (National Nonferrous Metals and Electronic Materials Testing Center), Germanium element standard solution (National Nonferrous Metals and Electronic Materials Testing Center).

[0024] 1.3 Analysis methods

[0025] (1) Accurately weigh 50 mg of sucrose octasulfate triethylamine sample, place it in a polytetrafluoroethylene digestion tank, add 4 mL of acetonitrile, seal it and load it into a microwave digestion instrument, and heat and digest it for 25 minutes according to a pre-set microwave digestion program. The microwave digestion program described in step (1) is: use a power of 800 W, heat up, heat to 160° C. within 15 minutes, then cool down, and stop the program after the temperature drops to 35° C. within 10 minutes; (2) After digestion, cool the mixture, add an appropriate amount of 10 v / v% nitric acid, transfer the mixture to a volumetric flask and dilute to volume with 10 v / v% nitric acid to obtain the test solution; (3) Prepare a series of standard working solutions containing the elements to be tested, test them using inductively coupled plasma mass spectrometry, draw a standard curve, and fit a linear equation. The concentrations of the standard working solutions prepared for drawing the standard curve are 0 μ g / L, 50 μ g / L, 100 μ g / L, 200 μ g / L, 400 μ g / L and 1000 μ g / L; (4) introducing the test solution obtained in steps (2) and (3) into an inductively coupled plasma mass spectrometer through a sampling system, and selecting the isotope of the metal element by combining the standard mode with the collision reaction cell method. 39 K and 23 Na, set the operating parameters of the inductively coupled plasma mass spectrometer to 72 Ge is used as the internal standard, and the inductively coupled plasma mass spectrometry is carried out quantitatively by online addition of the internal standard method, and the content of the element to be measured is determined according to the standard curve; preferably, the isotope of the metal element is 39 K and 23 Na, wherein, in step (3), the operating parameters of the inductively coupled plasma mass spectrometer are: injection time is 45s, flushing time is 50s, interval is 0.05s, nebulizing gas flow rate is 1.04L / min, nebulizing pool temperature is 2.9°C, nebulizing gas is argon, repeated measurement / times is 3, channel is 1, peristaltic pump speed is 60.0rpm, collision gas flow rate is 4.0mL / min, collision gas is helium, and cooling gas is argon.

[0026] The sample was not completely dissolved during the microwave digestion process, and the potassium and sodium contents in the sample were determined to be 0.035 ppb and 0.044 ppb, respectively.

[0027] Example 3 A method for determining potassium and sodium residues in sucrose octasulfate triethylamine by microwave digestion-inductively coupled plasma mass spectrometry comprises the following steps: 1.1 Experimental instruments and utensils Inductively coupled plasma mass spectrometer: iCAP TQs ICP-MS from Thermo Corporation, USA; Ultrapure water system: resistivity 18.2 MΩ·cm, Milli-Q Element A10 from Millipore, USA; Microwave digestion instrument: Shanghai Xinyi MDS-6G; 50mL FEP volumetric flask, 100mL FEP volumetric flask, 1000mL FEP volumetric flask, 10mL FEP measuring cylinder, 100mL FEP beaker, rinse repeatedly with ultrapure water 3-5 times.

[0028] 1.2 Experimental Reagents Ultrapure water, deionized water purified by Milli-Q Element A10 system; 69wt% nitric acid (superior grade), 36wt% hydrochloric acid (superior grade), and 99.95wt% acetonitrile (chromatographic grade) are commercially available reagents; Potassium element standard solution (National Nonferrous Metals and Electronic Materials Testing Center), Sodium element standard solution (National Nonferrous Metals and Electronic Materials Testing Center), Germanium element standard solution (National Nonferrous Metals and Electronic Materials Testing Center).

[0029] 1.3 Analysis methods

[0030] (1) Accurately weigh 50 mg of sucrose octasulfate triethylamine sample, place it in a polytetrafluoroethylene digestion tank, add 3 mL of acetonitrile and 1 mL of 36 wt% hydrochloric acid in sequence, seal it and place it in a microwave digestion instrument, and heat and digest it for 25 minutes according to a pre-set microwave digestion program. The microwave digestion program described in step (1) is: use a power of 800 W, heat up, heat to 160° C. within 15 minutes, then cool down, and stop the program after the temperature drops to 35° C. within 10 minutes; (2) After digestion, cool the mixture, add an appropriate amount of 10 v / v% nitric acid, transfer the mixture to a volumetric flask and dilute to volume with 10 v / v% nitric acid to obtain a test solution; (3) Prepare a series of standard working solutions containing the elements to be tested, test them using inductively coupled plasma mass spectrometry, draw a standard curve, and fit a linear equation. The concentrations of the standard working solutions prepared for drawing the standard curve are 0 μ g / L, 50 μ g / L, 100 μ g / L, 200 μ g / L, 400 μ g / L and 1000 μ g / L; (4) introducing the test solution obtained in steps (2) and (3) into an inductively coupled plasma mass spectrometer through a sampling system, and selecting the isotope of the metal element by combining the standard mode with the collision reaction cell method. 39 K and 23 Na, set the operating parameters of the inductively coupled plasma mass spectrometer to 72 Ge is used as the internal standard, and the inductively coupled plasma mass spectrometry is carried out quantitatively by online addition of the internal standard method, and the content of the element to be measured is determined according to the standard curve; preferably, the isotope of the metal element is 39 K and 23 Na, wherein, in step (3), the operating parameters of the inductively coupled plasma mass spectrometer are: injection time is 45s, flushing time is 50s, interval is 0.05s, nebulizing gas flow rate is 1.04L / min, nebulizing pool temperature is 2.9°C, nebulizing gas is argon, repeated measurement / times is 3, channel is 1, peristaltic pump speed is 60.0rpm, collision gas flow rate is 4.0mL / min, collision gas is helium, and cooling gas is argon.

[0031] The sample was not completely dissolved during the microwave digestion process, and the potassium and sodium contents in the sample were determined to be 0.008 ppb and 0.014 ppb, respectively.

[0032] Example 4 A method for determining potassium and sodium residues in sucrose octasulfate triethylamine by microwave digestion-inductively coupled plasma mass spectrometry comprises the following steps: 1.1 Experimental instruments and utensils Inductively coupled plasma mass spectrometer: iCAP TQs ICP-MS from Thermo Corporation, USA; Ultrapure water system: resistivity 18.2 MΩ·cm, Milli-Q Element A10 from Millipore, USA; Microwave digestion instrument: Shanghai Xinyi MDS-6G; 50mL FEP volumetric flask, 100mL FEP volumetric flask, 1000mL FEP volumetric flask, 10mL FEP measuring cylinder, 100mL FEP beaker, rinse repeatedly with ultrapure water 3-5 times.

[0033] 1.2 Experimental Reagents Ultrapure water, deionized water purified by Milli-Q Element A10 system; 69wt% nitric acid (superior purity) and 99.95wt% acetonitrile (chromatographic grade) are commercially available reagents; Potassium element standard solution (National Nonferrous Metals and Electronic Materials Testing Center), Sodium element standard solution (National Nonferrous Metals and Electronic Materials Testing Center), Germanium element standard solution (National Nonferrous Metals and Electronic Materials Testing Center).

[0034] 1.3 Analysis methods

[0035] (1) Accurately weigh 50 mg of sucrose octasulfate triethylamine sample, place it in a polytetrafluoroethylene digestion tank, add 3 mL of acetonitrile and 1 mL of 69 wt% nitric acid in sequence, seal it and place it in a microwave digestion instrument, and heat and digest it for 25 minutes according to a pre-set microwave digestion program. The microwave digestion program described in step (1) is: use a power of 800 W, heat up, heat to 160° C. within 15 minutes, then cool down, and stop the program after the temperature drops to 35° C. within 10 minutes; (2) After digestion, cool the mixture, add an appropriate amount of 10 v / v% nitric acid, transfer the mixture to a volumetric flask and dilute to volume with 10 v / v% nitric acid to obtain a test solution; (3) Prepare a series of standard working solutions containing the elements to be tested, test them using inductively coupled plasma mass spectrometry, draw a standard curve, and fit a linear equation. The concentrations of the standard working solutions prepared for drawing the standard curve are 0 μ g / L, 50 μ g / L, 100 μ g / L, 200 μ g / L, 400 μ g / L and 1000 μ g / L; (4) introducing the test solution obtained in steps (2) and (3) into an inductively coupled plasma mass spectrometer through a sampling system, and selecting the isotope of the metal element by combining the standard mode with the collision reaction cell method. 39 K and 23 Na, set the operating parameters of the inductively coupled plasma mass spectrometer to 72 Ge is used as the internal standard, and the inductively coupled plasma mass spectrometry is carried out quantitatively by online addition of the internal standard method, and the content of the element to be measured is determined according to the standard curve; preferably, the isotope of the metal element is 39 K and 23 Na, wherein, in step (3), the operating parameters of the inductively coupled plasma mass spectrometer are: injection time is 45s, flushing time is 50s, interval is 0.05s, nebulizing gas flow rate is 1.04L / min, nebulizing pool temperature is 2.9°C, nebulizing gas is argon, repeated measurement / times is 3, channel is 1, peristaltic pump speed is 60.0rpm, collision gas flow rate is 4.0mL / min, collision gas is helium, and cooling gas is argon.

[0036] The sample was not completely dissolved during the microwave digestion process, and the potassium and sodium contents in the sample were determined to be 0.028 ppb and 0.071 ppb, respectively.

[0037] Example 5 A method for determining potassium and sodium residues in sucrose octasulfate triethylamine by microwave digestion-inductively coupled plasma mass spectrometry comprises the following steps: 1.1 Experimental instruments and utensils Inductively coupled plasma mass spectrometer: iCAP TQs ICP-MS from Thermo Corporation, USA; Ultrapure water system: resistivity 18.2 MΩ·cm, Milli-Q Element A10 from Millipore, USA; Microwave digestion instrument: Shanghai Xinyi MDS-6G; 50mL FEP volumetric flask, 100mL FEP volumetric flask, 1000mL FEP volumetric flask, 10mL FEP measuring cylinder, 100mL FEP beaker, rinse repeatedly with ultrapure water 3-5 times.

[0038] 1.2 Experimental Reagents Ultrapure water, deionized water purified by Milli-Q Element A10 system; 69wt% nitric acid (superior grade), 71wt% perchloric acid (superior grade), and 99.95wt% acetonitrile (chromatographic grade) are commercially available reagents; Potassium element standard solution (National Nonferrous Metals and Electronic Materials Testing Center), Sodium element standard solution (National Nonferrous Metals and Electronic Materials Testing Center), Germanium element standard solution (National Nonferrous Metals and Electronic Materials Testing Center).

[0039] 1.3 Analysis methods

[0040] (1) Accurately weigh 50 mg of sucrose octasulfate triethylamine sample, place it in a polytetrafluoroethylene digestion tank, add 3 mL of acetonitrile and 1 mL of 71 wt% perchloric acid in sequence, seal it and place it in a microwave digestion instrument, and heat and digest it for 25 minutes according to a pre-set microwave digestion program. The microwave digestion program described in step (1) is: use a power of 800 W, heat up, heat to 160° C. within 15 minutes, then cool down, and stop the program after the temperature drops to 35° C. within 10 minutes; (2) After digestion, cool the mixture, add an appropriate amount of 10 v / v% nitric acid, transfer the mixture to a volumetric flask and dilute to volume with 10 v / v% nitric acid to obtain the test solution; (3) Prepare a series of standard working solutions containing the elements to be tested, test them using inductively coupled plasma mass spectrometry, draw a standard curve, and fit a linear equation. The concentrations of the standard working solutions prepared for drawing the standard curve are 0 μ g / L, 50 μ g / L, 100 μ g / L, 200 μ g / L, 400 μ g / L and 1000 μ g / L; (4) introducing the test solution obtained in steps (2) and (3) into an inductively coupled plasma mass spectrometer through a sampling system, and selecting the isotope of the metal element by combining the standard mode with the collision reaction cell method. 39 K and 23 Na, set the operating parameters of the inductively coupled plasma mass spectrometer to 72 Ge is used as the internal standard, and the inductively coupled plasma mass spectrometry is carried out quantitatively by online addition of the internal standard method, and the content of the element to be measured is determined according to the standard curve; preferably, the isotope of the metal element is 39 K and 23 Na, wherein, in step (3), the operating parameters of the inductively coupled plasma mass spectrometer are: injection time is 45s, flushing time is 50s, interval is 0.05s, nebulizing gas flow rate is 1.04L / min, nebulizing pool temperature is 2.9°C, nebulizing gas is argon, repeated measurement / times is 3, channel is 1, peristaltic pump speed is 60.0rpm, collision gas flow rate is 4.0mL / min, collision gas is helium, and cooling gas is argon.

[0041] The sample was completely dissolved, and the potassium and sodium contents in the sample were determined to be 6.389 ppb and 8.148 ppb, respectively.

[0042] Example 6 1. Exclusive inspection: Blank solution (10v / v% nitric acid solution): Measure 100mL of nitric acid, add appropriate amount of ultrapure water to dilute, cool and transfer to a 1000mL volumetric flask and dilute to the mark.

[0043] Preparation of potassium and sodium standard stock solutions: Accurately measure potassium standard solution and sodium standard solution (1000 μ g / mL)100 μ L, put it in a 100mL volumetric flask, add 10v / v% nitric acid solution to dilute to the scale, shake well, and use it as the standard stock solution STOCK (C=1000) of potassium and sodium elements. μ g / L).

[0044] Preparation of reference solution: Accurately measure 10mL of potassium and sodium standard stock solutions STOCK and place them in a 50mL volumetric flask, add 10v / v% nitric acid to dilute to the scale and shake well, as potassium and sodium standard solutions STD. (C=200 μ g / L) Test sample stock solution: accurately weigh about 500 mg of sucrose octasulfate triethylamine and place it in two polytetrafluoroethylene digestion tanks, add 3 mL of acetonitrile and 1 mL of 71 wt% perchloric acid respectively, place it in a microwave digestion furnace heated to 160°C for 15 minutes, then cool it down to 35°C within 10 minutes and stop the program. After the digestion is completed, add an appropriate amount of 10 v / v% nitric acid solution to dissolve and transfer to a 50 mL volumetric flask, dilute to the mark with 10 v / v% nitric acid solution, shake well, and use it as the test sample stock solution.

[0045] Test sample solution: Accurately measure 5 mL of the test sample stock solution and place it in a 10 mL volumetric flask. Dilute to the mark with 10 v / v% nitric acid solution and shake well.

[0046] Test sample spiked solution: Accurately measure 5 mL of test sample stock solution and 10 mL of potassium and sodium standard stock solutions into a 50 mL volumetric flask, dilute to the scale with 10 v / v% nitric acid solution, shake well, and obtain.

[0047] Preparation of internal standard solution: Accurately measure Ge element standard solution (1000 μ g / mL)20 μ Place L in a 100mL plastic volumetric bottle, dilute with 10v / v% nitric acid solution and make up to the mark, shake well, and you have it. (C=200 μ g / L) The results are shown in Table 1: Table 1 Specificity results

[0048] 2.2 Linear investigation: 2.2.1 Analysis method: refer to the analysis method in the examples 2.2.2 Solution preparation: Blank solution: 10v / v% nitric acid solution.

[0049] Preparation of potassium and sodium standard stock solutions: Accurately measure potassium and sodium standard solutions (1000 μ g / mL)100 μ L, put it in a 100mL volumetric flask, add 10v / v% nitric acid solution to dilute to the scale, shake well, and use it as the nickel element standard stock solution STOCK. (C=1000 μ g / L) Preparation of internal standard solution: Accurately measure Ge element standard solution (1000 μ g / mL)20 μ Place L in a 100mL plastic volumetric bottle, dilute with 10v / v% nitric acid solution and make up to the mark, shake well, and you have it. (C=200 μ g / L) Each linear solution was prepared according to the following table: Concentration level Amount of potassium and sodium standard stock solution (mL) Volumetric flask (mL) Theoretical concentration (g / L) Linear solution 1 0.0 50 0 Linear solution 2 2.5 50 50.0 Linear solution 3 5.0 50 100.0 Linear solution 4 10.0 50 200.0 Linear solution 5 20.0 50 400.0 Linear solution 6 50.0 50 1000.0 2.2.3 The results are shown in Table 2-2: Table 2-2 Linearity results table Element Name Linear equations Correlation coefficient r Potassium y=0.997x+2.0721 r=1.000 Sodium y=0.9977x+1.7529 r=1.000 0~1000 μ In the g / L range, the response values ​​of potassium and sodium elements are linear with the concentrations of potassium and sodium in the solution.

[0050] 2.3 Investigation of detection limit and quantification limit: 2.3.1 Analysis method: Refer to the analysis method in the examples 2.3.2 Solution preparation: Blank solution (10v / v% nitric acid solution): Measure 100mL of nitric acid, add appropriate amount of ultrapure water to dilute, cool and transfer to a 1000mL volumetric flask and dilute to the mark.

[0051] 2.3.3 The results are shown in Table 2-3: Table 2-3 Detection limit and quantification limit results Serial number Potassium K (g / L) Sodium (g / L) SD 5.0025 1.0155 3*SD 15.007 3.046 10*SD 50.025 10.155 LOD (g / g) 15.007 3.046 LOQ (g / g) 50.025 10.155 AET value 650 650 The quantitative limits of potassium and sodium were less than the corresponding 30% AET values.

[0052] 2.4 Accuracy test: 2.4.1 Analysis method: refer to the analysis method in 1.3 2.4.2 Solution preparation: Test sample stock solution: accurately weigh about 500 mg of sucrose octasulfate triethylamine and place it in two polytetrafluoroethylene digestion tanks, add 3 mL of acetonitrile and 1 mL of 71 wt% perchloric acid respectively, place it in a microwave digestion furnace heated to 160°C for 15 minutes, then cool it down to 35°C within 10 minutes and stop the program. After digestion, transfer it to a 50 mL volumetric flask and dilute it to the mark with 10 v / v% nitric acid solution, shake well, and use it as the test sample stock solution.

[0053] Test sample solution: Accurately measure 5 mL of the test sample stock solution and place it in a 50 mL volumetric flask. Dilute to the mark with 10 v / v% nitric acid solution and shake well.

[0054] Accuracy solution 1 (low): Take 5 mL of the test sample stock solution and 5 mL of the potassium and sodium standard stock solutions, add 50 mL of 10 v / v% nitric acid to dilute to the scale and shake well to make Accuracy solution 1. Prepare 3 copies in parallel.

[0055] Accuracy solution 2 (medium): Take 5 mL of the test sample stock solution and 10 mL of the potassium and sodium standard stock solutions, add 50 mL of 10 v / v% nitric acid to dilute to the scale and shake well to make the accuracy solution 2 Accuracy 2. Prepare three copies in parallel.

[0056] Accuracy solution 3 (high): Take 5 mL of the test sample stock solution and 20 mL of the potassium and sodium standard stock solutions, add 50 mL of 10 v / v% nitric acid to dilute to the scale and shake well to make the accuracy solution 3 Accuracy 3. Prepare 3 copies in parallel.

[0057] 2.4.3 The results are shown in Tables 2-4 and 2-5: Table 2-4 Potassium element accuracy results

[0058] Table 2-5 Sodium element accuracy results

[0059] The recovery rates of potassium and sodium elements meet the requirements of 70%~150%, and the RSD of the recovery rate meets the requirements of less than or equal to 20%.

[0060] 2.5 Precision inspection: 2.5.1 Repeatability study: 2.5.1.1 Analysis method: refer to the analysis method in the examples 2.5.1.2 Solution preparation: Blank solution: 10v / v% nitric acid Test sample stock solution: accurately weigh about 500 mg of sucrose octasulfate triethylamine and place it in two polytetrafluoroethylene digestion tanks, add 3 mL of acetonitrile and 1 mL of 71 wt% perchloric acid respectively, place it in a microwave digestion furnace heated to 160°C for 15 minutes, then cool it down to 35°C within 10 minutes and stop the program. After digestion, transfer it to a 50 mL volumetric flask and dilute it to the mark with 10 v / v% nitric acid solution, shake well, and use it as the test sample stock solution.

[0061] Repeatability solution: Take 5 mL of the test sample stock solution and 10 mL of potassium and sodium standard stock solutions, add 50 mL and dilute to the scale with 10 v / v% nitric acid and shake well to serve as the repeatability solution. Prepare 6 replicates in parallel.

[0062] Preparation of internal standard solution: Accurately measure Ge element standard solution (1000 μg / mL)20 μ Place L in a 100mL plastic volumetric bottle, dilute with 10v / v% nitric acid solution and make up to the mark, shake well, and you have it. (C=200 μ g / L) 2.5.1.3 The results are shown in Table 2-6: Table 2-6 Repeatability results

[0063] 2.5.2 Intermediate precision study: 2.5.2.1 Analytical methods:

[0064] 2.5.2.2 Solution preparation: Blank solution (10v / v% nitric acid solution): Measure 100mL of nitric acid, add appropriate amount of ultrapure water to dilute, cool and transfer to a 1000mL volumetric flask and dilute to the mark.

[0065] Preparation of potassium and sodium standard stock solutions: Accurately measure potassium standard solution and sodium standard solution (1000 μ g / mL)100 μ L, put it in a 100mL volumetric flask, add 10v / v% nitric acid solution to dilute to the scale, shake well, and use it as the standard stock solution STOCK (C=1000) of potassium and sodium elements. μ g / L).

[0066] Test sample stock solution: accurately weigh about 500 mg of sucrose octasulfate triethylamine and place it in two polytetrafluoroethylene digestion tanks, add 3 mL of acetonitrile and 1 mL of 30 wt% perchloric acid respectively, place it in a microwave digestion furnace heated to 160°C for 15 minutes, then cool it down to 35°C within 10 minutes and stop the program. After digestion is completed, transfer it to a 50 mL volumetric flask and dilute it to the mark with 10 v / v% nitric acid solution, shake it well, and use it as the test sample stock solution.

[0067] Intermediate precision solution: Accurately measure 5 mL of the sample stock solution and 10 mL of potassium and sodium standard stock solutions into a 50 mL volumetric flask, dilute to scale with 10 v / v% nitric acid solution, shake well, and obtain the intermediate precision solution. Prepare 6 copies in parallel.

[0068] Preparation of internal standard solution: Accurately measure Ge element standard solution (1000 μ g / mL)20 μ Place L in a 100mL plastic volumetric bottle, dilute with 10v / v% nitric acid solution and make up to the mark, shake well, and you have it. (C=200 μ g / L) Each linear solution was prepared according to the following table: Concentration level Amount of nickel element standard stock solution (mL) Volumetric flask (mL) Theoretical concentration (g / L) Linear solution 1 0.0 50 0 Linear solution 2 2.5 50 50.0 Linear solution 3 5.0 50 100.0 Linear solution 4 10.0 50 200.0 Linear solution 5 20.0 50 400.0 Linear solution 6 50.0 50 1000.0 2.5.2.3 The results are shown in Table 2-7: Table 2-7 Intermediate precision results table

[0069] The RSD of nickel detection results in six test sample spiked solutions by different experimenters was less than 20.0%, and the RSD of nickel detection results in twelve test sample spiked solutions was less than 20.0%.

[0070] 2.6 Stability study: 2.6.1 Analysis method: refer to the analysis method in 1.3 2.6.2 Solution preparation: Blank solution (10v / v% nitric acid solution): Measure 100mL of nitric acid, add appropriate amount of ultrapure water to dilute, cool and transfer to a 1000mL volumetric flask and dilute to the mark.

[0071] Preparation of potassium and sodium standard stock solutions: Accurately measure potassium standard solution and sodium standard solution (1000 μ g / mL)100 μ L, put it in a 100mL volumetric flask, add 10v / v% nitric acid solution to dilute to the scale, shake well, and use it as the standard stock solution STOCK (C=1000) of potassium and sodium elements. μ g / L).

[0072] Preparation of reference solution: Accurately measure 10mL of potassium and sodium standard stock solutions STOCK and place them in a 50mL volumetric flask, add 10v / v% nitric acid to dilute to the scale and shake well, as potassium and sodium standard solutions STD. (C=200 μ g / L) Test sample stock solution: accurately weigh about 500 mg of sucrose octasulfate triethylamine and place it in two polytetrafluoroethylene digestion tanks, add 3 mL of acetonitrile and 1 mL of 71 wt% perchloric acid respectively, place it in a microwave digestion furnace heated to 160°C for 15 minutes, then cool it down to 35°C within 10 minutes and stop the program. After digestion, transfer it to a 50 mL volumetric flask and dilute it to the mark with 10 v / v% nitric acid solution, shake well, and use it as the test sample stock solution.

[0073] Test sample spike solution: Accurately measure 5 mL of test sample stock solution and 10 mL of potassium and sodium standard stock solutions into a 50 mL volumetric flask, dilute to the scale with 10 v / v% nitric acid solution, shake well, and obtain as the intermediate precision solution.

[0074] Preparation of internal standard solution: Accurately measure Ge element standard solution (1000 μ g / mL)20 μ Place L in a 100mL plastic volumetric bottle, dilute with 10v / v% nitric acid solution and make up to the mark, shake well, and you have it. (C=200 μ g / L) 2.6.3 The results are shown in Tables 2-8 and 2-9: Table 2-8 Stability test results of reference solution Injection time, 1h Potassium K (g / L) Sodium (g / L) 0 249.811 228.711 1 234.784 221.565 Mean result (g / L) 242.298 225.138 RSD% 4.4 2.2 Table 2-9 Stability test results of the spiked solution of the test sample Injection time, h Potassium K (g / L) Sodium (g / L) 0 221.505 227.207 1 231.946 230.000 Mean result (g / L) 226.726 228.604 RSD% 3.3 0.9 When measured at different times, the RSD of the detection results of each target element in the reference solution and the test solution spiked with the test sample should not exceed 20.0%.

[0075] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A method for determining the residual potassium and sodium elements in sucrose octasulfate triethylamine by microwave digestion-inductively coupled plasma mass spectrometry, characterized in that: The following steps are involved: S1: Weigh a solid sample to be tested, place it in a digestion tank, add 99.95wt% acetonitrile and 70-72wt% perchloric acid in sequence, seal it and put it into a microwave digestion instrument, and heat and digest for 20-30min, wherein the volume ratio of acetonitrile to perchloric acid is 1-5:1; S2: After digestion, cool, add an appropriate amount of 7~13v / v% nitric acid, and transfer to a volumetric flask to obtain the test solution; S3: Prepare a series of standard working solutions containing the elements to be tested, test them using inductively coupled plasma mass spectrometry, draw a standard curve, and fit a linear equation. The concentrations of the standard working solutions prepared for drawing the standard curve are 0 μ g / L, 50 μ g / L, 100 μ g / L, 200 μ g / L, 400 μ g / L and 1000 μ g / L; S4: The test solution obtained in S2 is introduced into the inductively coupled plasma mass spectrometer through the injection system, and the standard mode combined with the collision reaction cell method and the online addition of the internal standard method are used for quantitative inductively coupled plasma mass spectrometry determination, and the content of the element to be measured is determined according to the standard curve.

2. The method for determining the residual potassium and sodium elements in sucrose octasulfate triethylamine by microwave digestion-inductively coupled plasma mass spectrometry according to claim 1, characterized in that: The grade of acetonitrile described in S1 is chromatography grade.

3. The method for determining the residual potassium and sodium elements in sucrose octasulfate triethylamine by microwave digestion-inductively coupled plasma mass spectrometry according to claim 1, characterized in that: The perchloric acid concentration in S1 is 71 wt %.

4. The method for determining the residual potassium and sodium elements in sucrose octasulfate triethylamine by microwave digestion-inductively coupled plasma mass spectrometry according to claim 1, characterized in that: The volume ratio of acetonitrile and perchloric acid in S1 is 3:

1.

5. The method for determining the residual potassium and sodium elements in sucrose octasulfate triethylamine by microwave digestion-inductively coupled plasma mass spectrometry according to claim 1, characterized in that: The nitric acid concentration in S2 is 10 v / v%.

6. The method for determining the residual potassium and sodium elements in sucrose octasulfate triethylamine by microwave digestion-inductively coupled plasma mass spectrometry according to claim 1, characterized in that: The microwave digestion program described in S1 is: use a power of 800 W, increase the temperature to 160°C within 15 minutes, then cool down to 35°C within 10 minutes and stop the program.

7. The method for determining the residual potassium and sodium elements in sucrose octasulfate triethylamine by microwave digestion-inductively coupled plasma mass spectrometry according to claim 1, characterized in that: In S3, the operating parameters of the inductively coupled plasma mass spectrometer are: injection time is 45s, flushing time is 50s, interval is 0.05s, nebulizing gas flow rate is 1.04L / min, nebulizing pool temperature is 2.9°C, nebulizing gas is argon, repeated measurement / times is 3, channel is 1, peristaltic pump speed is 60.0rpm, collision gas flow rate is 4.0mL / min, collision gas is helium, and cooling gas is argon.

8. The method for determining the residual potassium and sodium elements in sucrose octasulfate triethylamine by microwave digestion-inductively coupled plasma mass spectrometry according to claim 1, characterized in that: In S4, the test liquid is introduced into the inductively coupled plasma mass spectrometer through the injection system, the standard mode is combined with the collision reaction cell method, the isotope of the metal element is selected, and the working parameters of the inductively coupled plasma mass spectrometer are set. 72 Ge was used as the internal standard, and the online internal standard addition method was used for quantitative inductively coupled plasma mass spectrometry, and the content of the element to be measured was determined according to the standard curve; the isotopes of potassium and sodium are 39 K and 23 Nah.

9. Use of the method according to any one of claims 1 to 8 in determining the content of potassium and sodium.

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