Inductively coupled plasma emission spectrometry internal standard correction method for determination of elements in metal and alloy materials

Abstract

The application discloses a method for determining elements in metal and alloy materials by inductively coupled plasma emission spectrum internal standard correction, which comprises the following steps: dissolving boric acid and scandium trioxide to prepare an internal standard solution; determining internal standard spectral lines of internal standard elements; preparing a mixed standard solution of elements to be measured; dissolving metal and alloy materials, and then preparing a sample solution to be measured; testing element emission intensity by an inductively coupled plasma emission spectrometer, drawing a working curve, correcting long-wave elements by a long-wave internal standard line, correcting short-wave elements by a short-wave internal standard line, and measuring element content. In the application, the B and Sc double internal standard solution is simple to prepare, long-wave and short-wave elements in the same pretreatment solution can be simultaneously determined, sample determination time is shortened, different elements in the same sample are measured by using multiple pretreatment methods and different internal standards, one sample can complete multiple element detection, and the stability and accuracy of ICP-OES method for determining high content elements in metal and alloy materials are improved.

Description

Technical Field

[0001] This invention relates to the field of spectroscopic analysis technology, and in particular to an inductively coupled plasma emission spectroscopy internal standard correction method for element determination in metals and alloys. Background Technology

[0002] Metals and alloys play a vital role in national economy and defense construction, and their excellent comprehensive properties have led to their widespread application in hot-end fields such as aviation, aerospace, transportation, energy, and automobile manufacturing. The composition and content of the elements within a material significantly influence its performance; therefore, accurate detection of the elemental content in metals and alloys is essential.

[0003] In the analysis of metals and alloys, classical chemical methods are often insufficient for rapid, batch-based determinations due to their cumbersome operation and long experimental cycles. Instrumental analysis, on the other hand, is gaining increasing attention for its speed and simultaneous multi-element determination. For high-content measurements, internal standard methods are typically used for calibration to reduce matrix effects and instrument signal fluctuations. This also improves the reliability and stability of the calibration results. Long-wavelength internal standards are used to calibrate long-wavelength elements, and short-wavelength internal standards are used to calibrate short-wavelength elements. For example, when using Y as an internal standard in hydrochloric acid, two spectral lines, 360.07 nm and 224.30 nm, are used to calibrate the long-wavelength and short-wavelength analytical lines, respectively. However, in the analysis of metals and alloys containing high concentrations of elements such as W, Nb, and Mo, the solution in hydrochloric acid is prone to turbidity or even precipitation, thus affecting accurate determination.

[0004] Existing national, international, and American standards primarily use hydrochloric acid as the medium for determining the composition of metals and alloys. However, this method suffers from drawbacks such as neglecting internal standard correction, cumbersome operation, increased biocompatibility, limited number of elements measured, and narrow element content range. Patents such as CN112858261A and CN103604800A utilize ICP-AES (ICP-OES) combined with internal standard methods to measure major elements in alloys; however, these methods involve multiple internal standard elements, cumbersome operation, and the inability to simultaneously measure multiple elements using the same treatment solution. Summary of the Invention

[0005] The purpose of this invention is to provide an inductively coupled plasma atomic emission spectrometry (ICP-AES) internal standard calibration method for element determination in metals and alloys. By selecting a B and Sc dual internal standard solution to determine elements in metals and alloys, this method achieves multi-element coverage and simultaneous determination of the same treatment solution. It can effectively solve the above-mentioned problems and features good precision and accuracy, fast analysis speed, simultaneous determination of multiple elements, and simplified testing procedures.

[0006] To achieve the above objectives, the present invention provides the following solution:

[0007] A method for internal standard correction in inductively coupled plasma atomic emission spectrometry (ICP-AES) for elemental determination in metallic and alloy materials, comprising the following steps:

[0008] 1) Prepare the internal standard solution:

[0009] Boric acid and scandium trioxide were dissolved to prepare an internal standard solution;

[0010] 2) Determine the internal standard spectral lines of the internal standard elements:

[0011] The internal standard spectral lines of the internal standard elements are determined based on instrument recommendations, interfering elements, spectral intensity, and precision, including long-wavelength internal standard spectral lines and short-wavelength internal standard spectral lines.

[0012] 3) Prepare mixed standard solutions:

[0013] Prepare mixed standard solutions of the analyte with multiple concentration gradients, add internal standard solution, make up to volume, and shake well;

[0014] 4) Prepare the sample solution to be tested:

[0015] Weigh a certain mass of metal and alloy sample, dissolve it to prepare the sample solution to be tested, add internal standard solution, make up to volume, shake well, and perform blank test with the same sample.

[0016] 5) Sample testing:

[0017] The solutions prepared in steps 3) and 4) are scanned and measured using an inductively coupled plasma spectrometer (ICP-PMS) to determine the analytical spectral lines of the analytes. A calibration curve is plotted using ICP-PMS, and long-wavelength internal standard lines are used to correct long-wavelength elements and short-wavelength internal standard lines are used to correct short-wavelength elements. The emission intensity value of each element in the sample solution is measured, and the content of the corresponding element is determined from the calibration curve.

[0018] Further, in step 1), the boric acid and scandium trioxide are dissolved to prepare an internal standard solution, specifically including:

[0019] Weigh boric acid and scandium trioxide into 500 mL beakers respectively. Dissolve boric acid in 50 mL of deionized water and scandium trioxide in 50 mL of nitric acid. Heat until completely dissolved, cool, transfer to 5000 mL volumetric flasks, and finally dilute to volume with 5% nitric acid. Mix well to obtain the internal standard solution.

[0020] Furthermore, each 1 mL of internal standard solution contains 10 mg of boric acid and 200 μg of Sc element.

[0021] Further, in step 3), preparing a mixed standard solution of the analyte with multiple concentration gradients, adding an internal standard solution, making up to volume, and shaking well specifically includes:

[0022] Based on the standard stock solutions of the analyte, mixed standard solutions of the analyte with mass fractions of 0.10%, 0.50%, 1.00%, 3.00%, 5.00%, 7.00%, and 10.00% were prepared.

[0023] Add 1.00 mL of internal standard solution to ensure that the volume of hydrofluoric acid is 5% and the volume of aqua regia is 10%, and make up to 100 mL in a polytetrafluoroethylene plastic volumetric flask and shake well.

[0024] Furthermore, the mixed standard solution contains the main high-content elements of metals and alloys determined by ICP-OES, specifically including Al, V, Cr, Mn, Fe, Co, Ni, Cu, Si and W, Mo, Nb, Zr, Hf, Ta, Ti, and Re.

[0025] Further, in step 4), a certain mass of the metal and alloy sample is weighed, dissolved, and prepared into a test sample solution. An internal standard solution is added, the solution is brought to volume, and the mixture is shaken well. Specifically, this includes:

[0026] Weigh 0.07–0.10 g of the metal and alloy sample and place it in a 250 mL polytetrafluoroethylene beaker. Add 10 mL of water, 10 mL of hydrochloric acid, and 1–5 mL of nitric acid. Heat at low temperature until the sample is completely dissolved. Add 5 mL of hydrofluoric acid and heat at low temperature until the solution is clear. Cool to obtain the test sample solution. Transfer the test sample solution to a polytetrafluoroethylene plastic volumetric flask, add internal standard solution, and ensure 5% hydrofluoric acid. Make up to volume and shake well.

[0027] Further, the step of transferring the obtained sample solution to a polytetrafluoroethylene plastic volumetric flask, adding an internal standard solution, ensuring 5% hydrofluoric acid, making up to volume, and shaking well specifically includes:

[0028] When the mass fraction of the element to be measured is 0.1% to 12%, the volume for making up to 100 mL is used.

[0029] When the mass fraction of the element to be tested is 12-30%, the volume should be 250 mL. When the volume is 250 mL, 7.5 mL of hydrofluoric acid should be added to maintain the hydrofluoric acid volume at 5%.

[0030] Furthermore, when metal and alloy samples are difficult to dissolve, a sealed container and a microwave digester are used to assist in dissolution.

[0031] Further, in step 2), the internal standard elements are B and Sc, with the short-wavelength internal standard spectral line of element B at 182.641 nm as the short-wavelength internal standard spectral line and the long-wavelength internal standard spectral line of element Sc at 363.075 nm as the long-wavelength internal standard spectral line.

[0032] Further, in step 5), the analytical spectral lines of short-wavelength elements include: Co element 231.1nm, Ni element 216.5nm, W element 207.9nm, Mo element 202.03nm, Re element 221.4nm, and Si element 185.06nm;

[0033] The analytical spectral lines of long-wavelength elements include: Al 394.4 nm, V 310.2 nm, Cr 267.71 nm, Mn 293.93 nm, Fe 259.94 nm, Cu 327.39 nm, Nb 316.3 nm, Zr 343.82 nm, Hf 264.14 nm, Ta 240.06 nm, and Ti 338.37 nm.

[0034] According to specific embodiments provided by the present invention, the present invention discloses the following technical effects: The inductively coupled plasma atomic emission spectrometry (ICP-AES) internal standard calibration method for element determination in metals and alloys provided by the present invention firstly prepares boric acid and scandium trioxide into an internal standard solution, prepares a series of mixed standard solutions for the element to be measured, dissolves the metal and alloy material in hydrochloric acid, nitric acid, and hydrofluoric acid and then makes up to a final volume, selects the analytical spectral line of the element to be measured and the internal standard spectral line of the internal standard element, tests the intensity with an ICP-AES spectrometer and plots a working curve, corrects long-wavelength elements with long-wavelength internal standard spectral lines and corrects short-wavelength elements with short-wavelength internal standard spectral lines, and reads the content of the element to be measured from the working curve;

[0035] In this invention, the Sc and B dual internal standard solution is simple to prepare, uses reliable matrix materials, exhibits good stability, and adheres to the principles of internal standard selection. Dissolution is achieved using hydrochloric acid, nitric acid, or hydrofluoric acid, simplifying the dissolution process, resulting in a stable solution with a wide range of elemental content coverage. High concentrations of elements such as W, Mo, and Nb are stably present in hydrofluoric acid media, allowing for the simultaneous determination of multiple elements from a single solution. This avoids repetitive sample dissolution and reagent waste, thus improving analytical testing speed. Using B at 182.64 nm as the short-wavelength internal standard line and Sc at 363.07 nm as the long-wavelength internal standard line for testing high-concentration elements yields reliable results with good accuracy and precision. This effectively mitigates the effects of physical interference from instruments and matrix effects, enabling the simultaneous determination of long- and short-wavelength elements in the sample. Attached Figure Description

[0036] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0037] Figure 1This is a flowchart of the inductively coupled plasma emission spectroscopy internal standard correction method for element determination in metals and alloys according to the present invention. Detailed Implementation

[0038] The embodiments of the present invention are described in detail below. These embodiments are intended to explain the present invention and should not be construed as limiting the present invention. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in the art or according to the product instructions. Reagents or instruments used, unless otherwise specified, are all commercially available conventional products.

[0039] The instrument used was a Thermo Fisher Scientific ICAPPRO XPS ICP-OES emission spectrometer (manufactured by Thermo Fisher Scientific). Scanning mode: full spectrum scan; Sample introduction system: polytetrafluoroethylene (PTFE). Operating conditions were: RF generator: 1150W; Plasma gas flow rate: 12.5 L / min, auxiliary gas: 0.5 L / min, nebulizing carrier gas: 0.65 L / min, flushing pump speed: 45 rpm, reading time: 5 s, vertical observation height: 12 mm.

[0040] Main reagents: Hydrochloric acid: mass concentration 1.19 g / mL, analytical grade; Nitric acid: mass concentration 1.42 g / mL, analytical grade; Hydrofluoric acid: mass concentration 1.14 g / mL, analytical grade; Water is deionized water.

[0041] Standard stock solutions for preparing mixed standard solutions typically include:

[0042] 1000 μg / mL mixed standard stock solution of Al, V, Cr, Mn, Fe, Co, Ni, Cu, manufactured by Steel Research Institute NACK Testing Technology Co., Ltd.; No.: NCS1481039, medium: 10% HNO3 + trHCl.

[0043] 1000 μg / mL mixed standard stock solution of W, Mo, Nb, Zr, Hf, Ta, Ti, manufactured by Steel Research Institute NACK Testing Technology Co., Ltd.; No.: NCS148975, medium: 10% HNO3 + 2% HF.

[0044] 1000 μg / mL Re standard stock solution, manufactured by: Steel Research Institute NACK Testing Technology Co., Ltd. and National Steel Materials Testing Center; No.: GSBG62064-90, medium: 10% HCl.

[0045] 1000 μg / mL Si standard stock solution, manufacturer: Steel Research Institute NACK Testing Technology Co., Ltd., item number: NCS140500, medium: 1% HNO3 + 1.4% HF.

[0046] like Figure 1As shown, the inductively coupled plasma atomic emission spectrometry (ICP-AES) internal standard calibration method for element determination in metals and alloys provided by this invention includes the following steps:

[0047] 1) Prepare internal standard solution

[0048] Weigh boric acid and scandium trioxide into separate 500 mL beakers. Dissolve boric acid in 50 mL of deionized water and scandium trioxide in 50 mL of nitric acid, respectively. Heat until completely dissolved, cool, and transfer to a 5000 mL volumetric flask. Finally, dilute to volume with 5% nitric acid (v / v) and mix well. The 5% nitric acid is used to maintain the stability of the internal standard solution. Each 1 mL of internal standard solution contains 10 mg boric acid and 200 μg Sc.

[0049] 2) Determine the internal standard spectral lines of the internal standard elements.

[0050] The internal standard spectral lines of the internal standard elements were selected based on instrument recommendations, interfering elements, the influence of spectral intensity, and precision. The internal standard elements based on the internal standard solution were B and Sc. The internal standard principle for B was followed: B has five recommended short-wavelength spectral lines, which are similar in wavelength to the short-wavelength analytical lines of the analytes Co, Ni, W, Mo, etc. It is relatively stable in mixed acid-hydrofluoric acid media, and the content of B in metals and alloys is very low (and easily removed), thus not affecting the internal standard calibration.

[0051] 3) Prepare the mixed calibration solution

[0052] Prepare a mixed standard solution with mass fraction gradients of 0.10%, 0.50%, 1.00%, 3.00%, 5.00%, 7.00%, and 10.00%. Add 0.10 mL, 0.50 mL, 1.00 mL, 3.00 mL, 5.00 mL, 7.00 mL, and 10.00 mL of the 1000 μg / mL mixed standard solution to a volumetric flask. Add 1 mL of internal standard solution, ensuring 10% hydrochloric acid and 5% hydrofluoric acid are added. Make up to volume and mix well. Transfer 1.00 mL of the 1000 μg / mL standard solution to a 100 mL volumetric flask and dilute to 100 mL, corresponding to a mass fraction of 1.00%. The volume of hydrofluoric acid is approximately 5%. The prepared mixed standard solution contains Al (aluminum), V (vanadium), Cr (chromium), Mn (manganese), Fe (iron), Co (cobalt), Ni (nickel), Cu (copper), Si (silicon), W (tungsten), Mo (molybdenum), Nb (niobium), Zr (zirconium), Hf (hafnium), Ta (tantalum), Ti (titanium), and Re (rhenium), which are the main high-content elements for ICP-OES determination of metals and alloys.

[0053] The standard solution used for the mixed calibration solution of Al, V, Cr, Mn, Fe, Co, Ni, Cu, and Si is 1000 μg / mL; the mixed standard stock solution of Al, V, Cr, Mn, Fe, Co, Ni, and Cu and the standard stock solution of Si are 1000 μg / mL.

[0054] The mixed calibration solution for W, Mo, Nb, Zr, Hf, Ta, Ti, and Re uses a 1000 μg / mL mixed standard stock solution of W, Mo, Nb, Zr, Hf, Ta, and Ti, and a 1000 μg / mL Re standard stock solution.

[0055] 4) Prepare the sample solution to be tested.

[0056] Weigh out a batch of high-purity metals and alloys with a mass similar to that of the sample, and perform a blank test according to the sample. Perform a blank test along with the sample.

[0057] Weigh 0.07–0.10 g of the metal and alloy sample and place it in a 250 mL PTFE beaker. Add 10 mL of water, 10 mL of hydrochloric acid, and 1–5 mL of nitric acid. Heat at low temperature until the sample is completely dissolved. Add 5 mL of hydrofluoric acid and heat at low temperature until the solution is clear. Remove from heat and cool. Transfer the solution to a PTFE volumetric flask. Accurately add the internal standard solution according to Table 1, ensuring 5% hydrofluoric acid. Make up to volume and shake well.

[0058] Hydrochloric acid, nitric acid, and hydrofluoric acid were all of superior purity.

[0059] Table 1 Sample volume / final volume and internal standard addition volume

[0060]

[0061] As shown in Table 1, when the element mass fraction is 0.1-12%, the volume should be 100 mL; when the element mass fraction is 12-30%, the volume should be 250 mL; when the volume is 250 mL, 7.5 mL of hydrofluoric acid should be added to maintain the HF volume at approximately 5%.

[0062] In steel and high-temperature alloys, the testing range for special elements Si and Cr is 0.1% to 5% (mass fraction). For concentrations greater than 5%, wet methods are used for determination. For other elements Al, V, Mn, Fe, Co, Ni, Cu, W, Mo, Nb, Zr, Hf, Ta, Ti, and Re, some can be tested at concentrations from 0.1% to 30% (mass fraction).

[0063] When metal and alloy samples are difficult to dissolve, a sealed container or microwave digester can be used.

[0064] 5) Sample testing

[0065] The solutions prepared in steps 3) and 4) are scanned using an inductively coupled plasma spectrometer to determine the analytical spectral lines of the analyte. A calibration curve is plotted using the inductively coupled plasma spectrometer. Long-wavelength elements are corrected using long-wavelength internal standard spectral lines, and short-wavelength elements are corrected using short-wavelength internal standard spectral lines. The emission intensity value of each element in the sample solution is measured, and the content of the corresponding element is determined from the calibration curve.

[0066] During sample testing, two calibration curves were first tested from low to high concentrations for Al, V, Cr, Mn, Fe, Co, Ni, Cu, Si, and W, Mo, Nb, Zr, Hf, Ta, Ti, Re. A linear regression equation was plotted with the concentration (expressed as a mass percentage) of the calibration curves on the x-axis and intensity on the y-axis. The correlation coefficient of each calibration curve was ensured to be greater than 0.999. Then, the elemental content (mass percentage) of the sample solution was determined.

[0067] By testing a mixed standard solution of known concentration, the relationship between its response value and concentration is established. Then, by calculating the elemental emission intensity ratio of the sample, the elemental content of the sample can be determined.

[0068] Example 1: Comparison of different internal standard correction methods for ICP-OES determination of short-wavelength elements Co, Ni, W, and Mo

[0069] (1) Add internal standard elements and determine the method of addition.

[0070] Weigh 50.0000 g of analytical grade boric acid and 1.5338 g of 99.99% scandium trioxide into a 500 mL beaker that has been cleaned with hydrochloric acid and rinsed with deionized water, and cover with a glass lid. Dissolve in 50 mL of deionized water and 50 mL of nitric acid respectively, heat until completely dissolved, cool, transfer to a 5000 mL volumetric flask, and finally dilute to volume with 5% nitric acid and mix well.

[0071] (2) Selection of spectral lines of internal standard elements

[0072] Select the internal standard spectral line based on instrument recommendations, interfering elements, emission intensity effects, and precision requirements.

[0073] Table 2. Recommended B internal standard spectral lines, interfering elements, and relative intensities for the instrument.

[0074]

[0075] Table 3B Relative Standard Deviation of Internal Standard Lines

[0076]

[0077] According to Table 2, there are 5 recommended spectral lines for element B in the short-wavelength spectrum of the instrument. Based on the instrument's recommended spectral lines and interference, the main interfering elements for the B spectral lines are Al, Co, S, Ta, Mo, W, and Ni. The 208.959 nm and 208.893 nm spectral lines of B have significant interference, while the 181.837 nm line has relatively low intensity; therefore, these are not considered as internal standard lines. According to Table 3, the 182.64 nm spectral line of B has a relatively small standard deviation, mainly affected by background interference from element S in sulfuric acid medium. Considering all factors, the 182.64 nm B spectral line, which has low interference, high emission intensity, and high precision, is selected as the internal standard line for the short-wavelength analysis. Similarly, the 361.384 nm or 363.075 nm spectral lines of Sc are finally selected as the internal standard lines for the long-wavelength analysis.

[0078] (3) Preparation of mixed standard solutions

[0079] Prepare mixed standard solutions with mass fractions of 0.10%, 0.50%, 1.00%, 3.00%, 5.00%, 7.00%, and 10.00%. Add 1.00 mL of internal standard solution to ensure that the volume of hydrofluoric acid is approximately 5% and the volume of aqua regia is 10%. Make up to 100 mL in a plastic volumetric flask and shake well.

[0080] (4) Sample pretreatment

[0081] Weigh out a high-purity metal and alloy of similar mass to the sample, and perform blank treatment according to the sample.

[0082] Weigh 0.07–0.10 g of the metal and alloy sample and place it in a 250 mL polytetrafluoroethylene beaker. Add 10 mL of water, 10 mL of hydrochloric acid, and 1–5 mL of nitric acid. Heat at low temperature until the sample is completely dissolved. Add 5 mL of hydrofluoric acid and heat at low temperature until the solution is clear. Remove from heat and cool. Transfer the solution to a plastic volumetric flask. Accurately add the internal standard solution according to Table 1, ensuring 5% hydrofluoric acid. Make up to volume and shake well.

[0083] (5) Correct the short-wavelength analytical lines of the analyte using the B short-wavelength internal standard and the Sc long-wavelength internal standard.

[0084] Analytical lines for high-content elements in steel and high-temperature alloys and internal standard lines for internal standard elements were selected. Calibration curves were plotted using an inductively coupled plasma spectrometer. The content of steel and high-temperature alloy standard samples was measured repeatedly 11 times, and the accuracy of Sc long-wave internal standard correction for long-wave and short-wave elements, long-wave correction for long-wave elements, and short-wave correction for short-wave elements were compared.

[0085] First, the content of the standard sample was determined and repeated 11 times, with B short-wavelength internal standard (182.64nm) and Sc long-wavelength internal standard (363.07nm) as internal standards to correct the short-wavelength analytical lines of Co (231.1nm), Ni (216.5nm), W (207.91nm), and Mo (202.03nm).

[0086] Table 4 shows the accuracy of test results when Co 231.160nm was corrected using B 182.64nm and Sc 363.07nm as internal standards.

[0087]

[0088] Table 5 shows the accuracy of test results when Ni 216.552nm was corrected using B 182.64nm and Sc 363.07nm as internal standards.

[0089]

[0090] Table 6 shows the accuracy of test results when W = 207.911nm was corrected using B = 182.64nm and Sc = 363.07nm as internal standards.

[0091]

[0092] Table 7 shows the accuracy of test results when Mo is calibrated at 202.030 nm using B (182.64 nm) and Sc (363.07 nm) as internal standard lines.

[0093]

[0094] Tables 4 to 7 show that when using the Sc 363.07nm long-wavelength internal standard to correct the short-wavelength analytical lines of the analytes Co, Ni, W, and Mo, the effect is minimal at low element concentrations, but the numerical deviations are large and unstable at high concentrations. However, when using the B 182.64nm short-wavelength internal standard to correct the short-wavelength analytical lines of the analytes Co, Ni, W, and Mo, the test results show good accuracy.

[0095] (6) Use the B short-wave internal standard and the Sc long-wave internal standard to calibrate the short-wave and long-wave analytical lines of the analyte, respectively.

[0096] Following the principle of "long-wave to long-wave, short-wave to short-wave," a dual-standard mode of B and Sc was set up. The short-wavelength internal standard B (182.64 nm) was used to correct the short-wavelength wavelengths of Co and Mo (Co 231.16 nm, Mo 202.03 nm); the long-wavelength internal standard Sc (363.07 nm) was used to correct the long-wavelength wavelengths of Co and Mo (Co 238.892 nm, Mo 277.54 nm). The content of the standard samples was determined and repeated 11 times, and the average value and RSD were obtained.

[0097] Table 8 shows the accuracy of the test results when Co 231.16nm and Co 238.892nm were corrected using B 182.64nm and Sc 363.07nm as internal standard spectral lines, respectively.

[0098]

[0099] Table 9 shows the accuracy of test results when Mo 202.030nm and Mo 277.540nm were corrected using B 182.64nm and Sc 363.07nm as internal standards, respectively.

[0100]

[0101] Tables 8 and 9 show that using the B 182.64nm short-wavelength internal standard to correct short-wavelength elements has good precision and accuracy, and using the Sc 363.07nm long-wavelength internal standard to correct long-wavelength elements also has good precision and accuracy, fully meeting the testing and method requirements, and realizing the simultaneous determination of long-wavelength and short-wavelength elements in a single processing solution.

[0102] Example 2: Determination of high-content elements Al, V, Cr, Mn, Fe, Cu, Nb, Hf, Ta, Ti, and Si in iron, steel, and high-temperature alloys

[0103] (1) Select B and Sc as internal index elements.

[0104] Weigh 50.0000 g of analytical grade boric acid and 1.5338 g of 99.99% scandium trioxide into a 500 mL beaker that has been cleaned with hydrochloric acid and rinsed with deionized water, and cover with a glass lid. Dissolve in 50 mL of deionized water and 50 mL of nitric acid respectively, heat until completely dissolved, cool, transfer to a 5000 mL volumetric flask, and finally dilute to volume with 5% nitric acid and mix well.

[0105] (2) Preparation of mixed standard solutions

[0106] Prepare a mixed standard solution with mass fractions of 0.10%, 0.50%, 1.00%, 3.00%, 5.00%, 7.00%, and 10.00%. Add 1.00 mL of internal standard solution to ensure that the volume of hydrofluoric acid is approximately 5% and the volume of aqua regia is 10%. Make up the volume in a 100 mL plastic volumetric flask and shake well.

[0107] (3) Preparation of sample solution

[0108] Weigh 0.10 g of steel and high-temperature alloy standard sample, place it in a sealed container, add 10 mL of hydrochloric acid, 2 mL of nitric acid, and 5 mL of hydrofluoric acid, seal the container, and place it in an oven at no more than 90°C for 2 hours. Remove and cool, transfer the solution to a plastic volumetric flask, dilute to volume, and shake well.

[0109] (4) Establish calibration curves and determine elemental content

[0110] The analytical lines were selected as follows: Al (394.4 nm), V (310.2 nm), Cr (267.71 nm), Mn (293.93 nm), Fe (259.94 nm), Cu (327.39 nm), Nb (316.3 nm), Hf (264.14 nm), Ta (240.06 nm), Ti (338.37 nm), and Si (185.06 nm). The long-wavelength internal standard line was Sc (363.07 nm), and the short-wavelength internal standard line was B (182.64 nm). An analytical method was established on the instrument software, and the intensity ratio of the analytical line of the analyte in the calibration solution to the reference line of the internal standard element Sc (363.07 nm) was measured. A linear regression was performed with the concentration of the calibration solution on the x-axis and the intensity ratio on the y-axis. The linearity of the calibration curve was checked by calculating the correlation coefficient, and the correlation coefficients for Al, V, Cr, Mn, Fe, Cu, Nb, Hf, Ta, and Ti were >0.999. The content of the element to be measured was obtained by calibration curve and compared with the standard values ​​of the element in each standard sample. The results are as follows.

[0111] Table 10. Elemental Al test results in steel and high-temperature alloy samples.

[0112]

[0113]

[0114] Table 11. Element V test results in steel and high-temperature alloy samples.

[0115]

[0116] Table 12 Elemental Cr Test Results in Steel and High-Temperature Alloy Samples

[0117]

Claims

1. A method for internal standard calibration of inductively coupled plasma atomic emission spectrometry for element determination in metallic and alloy materials, characterized in that, Includes the following steps: 1) Prepare the internal standard solution: Boric acid and scandium trioxide were dissolved to prepare an internal standard solution; 2) Determine the internal standard spectral lines of the internal standard elements: The internal standard spectral lines of the internal standard elements are determined based on instrument recommendations, interfering elements, spectral intensity, and precision, including long-wavelength internal standard spectral lines and short-wavelength internal standard spectral lines. 3) Prepare mixed standard solutions: Prepare mixed standard solutions of the analyte with multiple concentration gradients, add internal standard solution, make up to volume, and shake well; 4) Prepare the sample solution to be tested: Weigh a certain mass of metal and alloy sample, dissolve it to prepare the sample solution to be tested, add internal standard solution, make up to volume, and shake well; 5) Sample testing: The solutions prepared in steps 3) and 4) are scanned using an inductively coupled plasma spectrometer to determine the analytical spectral lines of the analyte. A calibration curve is plotted using the inductively coupled plasma spectrometer. Long-wavelength elements are corrected using long-wavelength internal standard spectral lines, and short-wavelength elements are corrected using short-wavelength internal standard spectral lines. The emission intensity value of each element in the sample solution is measured, and the content of the corresponding element is determined from the calibration curve.

2. The internal standard correction method of inductively coupled plasma emission spectrometry for the determination of elements in metal and alloy materials according to claim 1, characterized in that, In step 1), boric acid and scandium trioxide are dissolved to prepare an internal standard solution, specifically including: Weigh boric acid and scandium trioxide into 500 mL beakers respectively. Dissolve boric acid in 50 mL of deionized water and scandium trioxide in 50 mL of nitric acid. Heat until completely dissolved, cool, transfer to 5000 mL volumetric flasks, and finally dilute to volume with 5% nitric acid. Mix well to obtain the internal standard solution.

3. The internal standard calibration method of inductively coupled plasma emission spectrometry for the determination of elements in metal and alloy materials according to claim 2, characterized in that, Each 1 mL of internal standard solution contains 10 mg of boric acid and 200 μg of Sc element.

4. The inductively coupled plasma atomic emission spectrometry internal standard correction method for element determination in metallic and alloy materials according to claim 1, characterized in that, In step 3), preparing a mixed standard solution of the analyte with multiple concentration gradients, adding an internal standard solution, making up to volume, and shaking well specifically includes: Based on the standard stock solutions of the analyte, mixed standard solutions of the analyte with mass fractions of 0.10%, 0.50%, 1.00%, 3.00%, 5.00%, 7.00%, and 10.00% were prepared. Add 1.00 mL of internal standard solution to ensure that the volume of hydrofluoric acid is 5% and the volume of aqua regia is 10%, and make up to 100 mL in a polytetrafluoroethylene plastic volumetric flask and shake well.

5. The internal standard correction method of inductively coupled plasma emission spectrometry for the determination of elements in metal and alloy materials according to claim 4, characterized in that, The mixed standard solution contains the main high-content elements of metals and alloys determined by ICP-OES, specifically including Al, V, Cr, Mn, Fe, Co, Ni, Cu, Si and W, Mo, Nb, Zr, Hf, Ta, Ti, and Re.

6. The internal standard calibration method of inductively coupled plasma emission spectrometry for the determination of elements in metal and alloy materials according to claim 1, characterized in that, In step 4), a certain mass of metal and alloy sample is weighed, dissolved, and prepared into a test sample solution. An internal standard solution is added, the solution is brought to volume, and the mixture is shaken well. Specifically, this includes: Weigh 0.07–0.10 g of the metal and alloy sample and place it in a 250 mL polytetrafluoroethylene beaker. Add 10 mL of water, 10 mL of hydrochloric acid, and 1–5 mL of nitric acid. Heat at low temperature until the sample is completely dissolved. Add 5 mL of hydrofluoric acid and heat at low temperature until the solution is clear. Cool to obtain the test sample solution. Transfer the obtained test sample solution to a polytetrafluoroethylene plastic volumetric flask, add internal standard solution, and ensure 5% hydrofluoric acid. Make up to volume and shake well.

7. The inductively coupled plasma atomic emission spectrometry internal standard correction method for element determination in metallic and alloy materials according to claim 6, characterized in that, The process of transferring the obtained sample solution into a polytetrafluoroethylene (PTFE) volumetric flask, adding internal standard solution, ensuring 5% hydrofluoric acid, making up to volume, and shaking well includes: When the mass fraction of the element to be measured is 0.1% to 12%, the volume for making up to 100 mL is used. When the mass fraction of the element to be tested is 12-30%, the volume should be 250 mL. When the volume is 250 mL, 7.5 mL of hydrofluoric acid should be added to maintain the hydrofluoric acid volume at 5%.

8. The inductively coupled plasma atomic emission spectrometry internal standard correction method for element determination in metallic and alloy materials according to claim 6, characterized in that, When metal and alloy samples are difficult to dissolve, a sealed container and a microwave digester are used to assist in dissolution.

9. The inductively coupled plasma atomic emission spectrometry internal standard correction method for element determination in metallic and alloy materials according to claim 1, characterized in that, In step 2), the internal standard elements are B and Sc. The short-wavelength internal standard spectral line of element B at 182.641 nm is used as the short-wavelength internal standard spectral line, and the long-wavelength internal standard spectral line of element Sc at 363.075 nm is used as the long-wavelength internal standard spectral line.

10. The inductively coupled plasma atomic emission spectrometry internal standard correction method for element determination in metallic and alloy materials according to claim 5, characterized in that, In step 5), the analytical spectral lines of short-wavelength elements include: Co element 231.1nm, Ni element 216.5nm, W element 207.9nm, Mo element 202.03nm, Re element 221.4nm, and Si element 185.06nm. The analytical spectral lines of long-wavelength elements include: Al 394.4 nm, V 310.2 nm, Cr 267.71 nm, Mn 293.93 nm, Fe 259.94 nm, Cu 327.39 nm, Nb 316.3 nm, Zr 343.82 nm, Hf 264.14 nm, Ta 240.06 nm, and Ti 338.37 nm.

Images