Quantitative analysis method of metal element Ni in complex matrix

Abstract

The invention provides a quantitative analysis method for a metal element Ni in a complex matrix, which comprises the following steps: evaporating to dryness liquid to be detected to obtain an evaporated to dryness sample; adding the evaporated sample into concentrated nitric acid for soaking, and digesting; carrying out acid removal on the digested sample, cooling to a constant volume to obtain a primary sample solution, filtering the primary sample solution, and diluting with dilute nitric acid to obtain a to-be-detected sample solution; detecting by using a helium collision mode of an inductively coupled plasma mass spectrometer: establishing a linear regression equation based on Ni element signal intensity and corresponding concentration of a blank solution and a plurality of Ni element-containing mixed standard solutions with different concentration gradients, and taking the linear regression equation as a quantitative standard curve equation of the Ni element; detecting the sample solution to be detected by using a helium collision mode of an inductively coupled plasma mass spectrometer to obtain the signal intensity of the Ni element in the sample solution; and obtaining the concentration of the metal element Ni in the sample solution to be detected based on the signal intensity of the Ni element in the sample solution and the quantitative standard curve equation.

Description

Technical Field

[0001] The invention belongs to the field of energy chemical industry and analysis technology, and specifically relates to a quantitative analysis method of the metal element Ni in a complex matrix. Background Art

[0002] 1,4-Butanediol (BOD), also known as 1,4-dihydroxybutane and 1,4-butylene glycol, is an important chemical product. It can be used to produce a variety of high value-added fine chemical products such as tetrahydrofuran (THF), γ-butyrolactone (GBL), butylene terephthalate (PBS), polybutylene terephthalate-adipate (PBAT), etc. It is widely used in chemical, pharmaceutical, papermaking, automobile and daily chemical industries.

[0003] In recent years, with the improvement of people's living standards, more and more countries and regions have begun to take improving the quality of the ecological environment as their construction goals. The demand for environmentally friendly materials such as biodegradable plastics PBS and PBAT has increased significantly, and the production of its core raw material 1,4-butanediol (BDO) has received widespread attention. Usually, the industry often uses the acetylene aldehyde method to prepare 1,4-butanediol, and its core technology is the catalytic hydrogenation of 1,4-butynediol. Nickel-based catalysts, as an economical, clean and easy-to-prepare catalyst, play an important role in the production of 1,4-butanediol.

[0004] Detecting the content of metal element Ni in the working fluid during the process is of great significance for studying the activity and stability of the catalyst in the production of 1,4-butanediol, evaluating the catalyst recovery effect in the production process and improving the production process. The production working fluid usually contains raw materials and a variety of intermediates, such as water, 1,4-butanediol, butanol, 1,4-butynediol and other mixtures of organic and inorganic substances. The sample composition is very complex, and there are many interferences to the detection of metal element Ni. At present, the quantitative analysis method of metal element Ni in complex matrices is still imperfect, and it is impossible to quickly and accurately realize the quantitative detection of metal element Ni in complex matrices. Summary of the invention

[0005] In view of the problems existing in the prior art, the present invention provides a method for quantitative analysis of the metal element Ni in a complex matrix, so as to solve the problem that the existing related technology cannot quickly and accurately realize the quantitative detection of the metal element Ni in a complex matrix.

[0006] The present invention is achieved through the following technical solutions: A quantitative analysis method for the metal element Ni in a complex matrix, characterized by comprising the following steps: Evaporating the liquid to be tested to dryness to obtain an evaporated sample; The evaporated sample was immersed in concentrated nitric acid and digested; The sample after digestion is subjected to acid removal, and then cooled and fixed to volume to obtain a preliminary sample solution, the preliminary sample solution is filtered and diluted with dilute nitric acid to obtain a sample solution to be tested; The helium collision mode of the inductively coupled plasma mass spectrometer was used for detection: blank solution and mixed standard solutions containing Ni element with different concentration gradients were used. The linear regression equation was established based on the signal intensity of Ni element and its corresponding concentration by using the external standard method, and the linear regression equation was used as the quantitative standard curve equation of Ni element; The sample solution to be tested is detected using the helium collision mode of the inductively coupled plasma mass spectrometer to obtain the signal intensity of the Ni element in the sample solution; Based on the signal intensity of the Ni element in the sample solution and combined with the quantitative standard curve equation, the concentration of the metal element Ni in the sample solution to be tested is obtained.

[0007] Preferably, the liquid to be tested is a complex matrix, and the complex matrix is ​​an alcohol substance, and the alcohol substance contains a large amount of organic components that have adverse effects on the inorganic injection system of the inductively coupled plasma mass spectrometer and substances that are not suitable for direct participation in microwave digestion.

[0008] Preferably, the process of evaporating the liquid to be tested is: The liquid to be tested was placed in a polytetrafluoroethylene digestion tank and subjected to an acid removal apparatus at 200°C for at least 60 min to obtain an evaporated sample.

[0009] Preferably, the evaporated sample is soaked in concentrated nitric acid, left to stand for 15 minutes, then sealed and placed in a microwave digestion instrument for digestion; The nitric acid used in the digestion process in the microwave digestion instrument is 65.0%-68.0% high-grade pure concentrated nitric acid; The process of microwave digestion is: Heat to 80°C within 25 minutes and keep warm for 10 minutes; In the following 10 minutes, the temperature was raised to 120°C and kept at this temperature for 10 minutes; In the following 10 minutes, the temperature was raised to 180°C, kept at that temperature for 10 minutes, and then lowered to 60°C.

[0010] Preferably, the process of removing acid from the sample after digestion is as follows: The digested sample was placed in an acid remover to remove acid. The temperature of the acid remover was 100° C. and lasted for at least 60 minutes. The preliminary sample solution was filtered through a 0.45 μm filter membrane.

[0011] Preferably, the helium collision mode detection of the inductively coupled plasma mass spectrometer is: Use MS / MS scanning mode and helium KED working mode to perform kinetic energy identification to eliminate interference and select the isotopes of the metal elements. 60 Ni, and determine the content of the element to be tested based on the standard curve.

[0012] Preferably, the plurality of mixed standard solutions containing Ni element with different concentration gradients are: The Ni-containing multi-element mixed standard solution with a concentration of 100 μg / mL was diluted to 10 μg / L, 20 μg / L and 50 μg / L with 1% high-grade pure dilute nitric acid. The diluted solutions were mixed standard solutions containing Ni elements with different concentration gradients.

[0013] Preferably, the blank solution and the preliminary sample solution are prepared using 1% high-grade pure dilute nitric acid.

[0014] Preferably, the detection conditions of the inductively coupled plasma mass spectrometer are: Scan 20 times and repeat the measurement 3 times. The injection time is 30 s, the flushing time is 30 s, the peristaltic pump speed is 35 rpm, the nebulizing gas is argon, the nebulizing gas flow rate is 0.92 L / min, and the collision gas is helium, and the collision gas flow rate is 5 mL / min.

[0015] Preferably, the microwave digestion instrument is: CEMMARS7 ultra-high pressure microwave digestion and extraction system; The instrument used in the inductively coupled plasma mass spectrometry is: PerkinElmer NexION 5000G inductively coupled plasma mass spectrometer.

[0016] Compared with the prior art, the present invention has the following beneficial technical effects: The invention provides a quantitative analysis method for the metal element Ni in a complex matrix, comprising the following steps: evaporating a liquid to be tested to obtain an evaporated sample; soaking the evaporated sample in concentrated nitric acid and placing the evaporated sample in a microwave digester for digestion; removing acid from the sample after digestion, cooling and constant volume to obtain a preliminary sample solution, filtering the preliminary sample solution and diluting it with dilute nitric acid to obtain a sample solution to be tested; using a helium collision mode of an inductively coupled plasma mass spectrometer to detect: a blank solution and a plurality of Ni element mixed standard solutions with different concentration gradients, establishing a linear regression equation based on Ni element signal intensity and its corresponding concentration, and using the linear regression equation as a quantitative standard curve equation of the Ni element; using a helium collision mode of an inductively coupled plasma mass spectrometer to detect the sample solution to be tested to obtain the Ni element signal intensity in the sample solution; obtaining the concentration of the metal element Ni in the sample solution to be tested based on the Ni element signal intensity in the sample solution and the quantitative standard curve equation; the application can remove organic matter in the complex matrix, prepare the sample stock solution into a stable inorganic acid solution, remove a plurality of possible interferences with the Ni element, and obtain a more accurate quantitative analysis result of the metal element Ni in the complex matrix.

[0017] Furthermore, this method cleverly avoids the potential damage of traditional treatment methods to the inorganic sampling system of inductively coupled plasma mass spectrometer (ICP-MS), ensuring the efficient and stable operation of the analytical instrument and the accuracy of the measurement results. Through innovative sample pretreatment steps, interferences are effectively removed, the detection sensitivity and reproducibility of Ni are improved, and a reliable technical approach is provided for the accurate quantification of trace and ultra-trace Ni elements in complex matrices, which simplifies the operation process, shortens the analysis cycle, and reduces the analysis cost.

[0018] Furthermore, this method places the liquid to be tested in a polytetrafluoroethylene digestion tank, and uses an acid-dripping device to continuously heat at 200°C for at least 60 minutes for evaporation, which optimizes the pretreatment process for quantitative analysis of the metal element Ni in complex matrices. The excellent chemical stability and high temperature resistance of the polytetrafluoroethylene digestion tank ensure the purity and safety of the sample during the evaporation process, and effectively avoid the contamination of the container to the sample. The high-temperature and long-term evaporation treatment not only removes a large amount of organic components and moisture in the sample, reducing the interference of subsequent analysis, but also allows the Ni element to be enriched, improving the sensitivity and accuracy of the detection. In addition, the process is simple to operate and easy to control, providing an efficient and reliable sample pretreatment method for the quantitative analysis of metal elements in complex matrices.

[0019] Furthermore, this method uses 65.0%-68.0% high-grade pure concentrated nitric acid to soak and microwave digest the evaporated samples, which greatly improves the accuracy and efficiency of the quantitative analysis of Ni in complex matrices. By strictly controlling the concentration of nitric acid, the uniformity and effectiveness of the digestion process are ensured, and incomplete digestion or sample loss caused by improper concentration is avoided. The temperature and time program design of microwave digestion is scientific and reasonable. The strategy of gradually heating and keeping warm effectively promotes the release and extraction of Ni in the sample, while maintaining the stability of the digestion system and reducing the generation of by-products. The entire digestion process not only improves the recovery rate of Ni, but also simplifies the subsequent processing steps and shortens the analysis cycle.

[0020] Furthermore, the method places the sample after digestion in an acid removal instrument and continues to remove the acid at 100°C for at least 60 minutes, thereby ensuring the complete removal of residual nitric acid in the sample, reducing the potential interference of high acidity on subsequent analysis steps, and improving the accuracy and stability of the analysis. The preliminary sample solution is finely filtered through a 0.45μm filter membrane to effectively remove possible solid particles and impurities, further purify the sample, avoid the risk of blockage and contamination of the analytical instrument, optimize the final link of sample pretreatment, and improve the efficiency and reliability of the entire analysis process.

[0021] Furthermore, this method uses the helium collision mode (KED) of the inductively coupled plasma mass spectrometer (ICP-MS) combined with the MS / MS scanning mode for detection, which significantly improves the accuracy and anti-interference ability of the quantitative analysis of the metal element Ni in complex matrices. The kinetic energy discrimination is performed through the helium KED working mode, which effectively eliminates the interference of polyatomic ions and other interferences on the target element signal, ensuring the accuracy of the detection results. The isotopes of the Ni element are selected 60 Ni is used as the detection object to further improve the specificity and sensitivity of the analysis. The content is determined in combination with the standard curve, making the measurement results more reliable and traceable.

[0022] Furthermore, this method ensures the stability and purity of the solution by accurately diluting a high-concentration (100 μg / mL) Ni-containing multi-element mixed standard solution to a low concentration range (10 μg / L, 20 μg / L, 50 μg / L) using 1% high-grade pure dilute nitric acid as a diluent. This series of mixed standard solutions with concentration gradients provides abundant standard reference points for the quantitative analysis of Ni in complex matrices, which helps to construct an accurate standard curve, thereby improving the accuracy and reliability of quantitative analysis.

[0023] Furthermore, this method uses 1% high-grade pure dilute nitric acid as a diluent for the blank solution and the preliminary sample solution, which ensures the consistency and high purity of the solution during the experiment, effectively reduces the interference of impurities on the analysis results, and improves the accuracy of the quantitative analysis of the Ni element.

[0024] Furthermore, the inductively coupled plasma mass spectrometer (ICP-MS) detection conditions set in detail in this method, including the number of scans, the number of repeated measurements, the injection time, the flushing time, the peristaltic pump speed, the type and flow rate of the nebulizer gas and the collision gas, have been carefully optimized to maximize the performance of ICP-MS and ensure high sensitivity, high resolution and high stability for Ni element detection. In particular, the use of helium as a collision gas, combined with the KED working mode, further enhances the anti-interference ability of ICP-MS in complex matrices and improves the accuracy of the analysis results.

[0025] Furthermore, the CEMMARS7 ultrahigh pressure microwave digestion and extraction system and PerkinElmer NexION 5000G ICP-MS instrument specified in this method not only simplify the operation process and shorten the analysis time, but also ensure the reliability and repeatability of the analysis data. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a standard curve diagram of Ni element quantitative analysis of the examples disclosed in the present invention. DETAILED DESCRIPTION

[0027] The present invention is further described in detail below in conjunction with specific embodiments, which are intended to explain the present invention rather than to limit it.

[0028] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0029] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0030] The disclosed embodiment of the present invention provides a method for quantitative analysis of the metal element Ni in a complex matrix, comprising the following steps: Evaporating the liquid to be tested to dryness to obtain an evaporated sample; The evaporated sample was soaked in concentrated nitric acid and placed in a microwave digestion apparatus for digestion; The sample after digestion is subjected to acid removal, and then cooled and fixed to volume to obtain a preliminary sample solution, the preliminary sample solution is filtered and diluted with dilute nitric acid to obtain a sample solution to be tested; The helium collision mode of the inductively coupled plasma mass spectrometer was used for detection: blank solution and mixed standard solutions containing Ni element with different concentration gradients. A linear regression equation was established based on the signal intensity of Ni element and its corresponding concentration, and the linear regression equation was used as the quantitative standard curve equation of Ni element; The sample solution to be tested is detected using the helium collision mode of the inductively coupled plasma mass spectrometer to obtain the signal intensity of the Ni element in the sample solution; Based on the signal intensity of the Ni element in the sample solution and combined with the quantitative standard curve equation, the concentration of the metal element Ni in the sample solution to be tested is obtained.

[0031] Preferably, in the embodiment of the present disclosure, the liquid to be tested is a complex matrix, and the complex matrix is ​​an alcohol substance. The alcohol substance contains a large amount of organic components that have adverse effects on the inorganic injection system of the inductively coupled plasma mass spectrometer and substances that are not suitable for direct participation in microwave digestion. The organic components and certain alcohol substances may interfere with or affect the analysis results; specifically, the complex matrix includes inorganic and organic mixtures such as water, 1,4-butanediol, butanol, butynediol and metal catalysts.

[0032] Preferably, in the embodiment of the present disclosure, the process of evaporating the liquid to be tested is: The liquid to be tested was placed in a polytetrafluoroethylene digestion tank and subjected to an acid removal apparatus at 200°C for at least 60 min to obtain an evaporated sample.

[0033] Preferably, in the disclosed embodiment, the evaporated sample is soaked in concentrated nitric acid, left to stand for 15 minutes, then sealed, and placed in a microwave digestion instrument for digestion; The nitric acid used in the digestion process in the microwave digestion instrument is 65.0%-68.0% high-grade pure concentrated nitric acid; The process of microwave digestion is: Heat to 80°C within 25 minutes and keep warm for 10 minutes; In the following 10 minutes, the temperature was raised to 120°C and kept at this temperature for 10 minutes; In the following 10 minutes, the temperature was raised to 180°C, kept at that temperature for 10 minutes, and then lowered to 60°C.

[0034] Preferably, in the disclosed embodiment, the process of removing acid from the sample after digestion is as follows: The digested sample was placed in an acid remover to remove acid. The temperature of the acid remover was 100° C. and lasted for at least 60 minutes. The preliminary sample solution was filtered through a 0.45 μm filter membrane.

[0035] Preferably, in the disclosed embodiment, the helium collision mode detection of the inductively coupled plasma mass spectrometer is: Use MS / MS scanning mode and helium KED working mode to perform kinetic energy identification to eliminate interference and select the isotopes of the metal elements. 60 Ni, and determine the content of the element to be tested based on the standard curve.

[0036] Preferably, in the disclosed embodiment, the external standard method is used to establish the Ni element calibration line, and the multiple Ni element mixed standard solutions with different concentration gradients are: The Ni-containing multi-element mixed standard solution with a concentration of 100 μg / mL was diluted to 10 μg / L, 20 μg / L and 50 μg / L with 1% high-grade pure dilute nitric acid. The diluted solutions were mixed standard solutions containing Ni elements with different concentration gradients.

[0037] Preferably, in the disclosed embodiment, high-grade pure dilute nitric acid with a concentration of 1% is used to prepare the blank solution and dilute the preliminary sample solution.

[0038] Preferably, in the embodiment of the present disclosure, the detection conditions of the inductively coupled plasma mass spectrometer are: Scan 20 times and repeat the measurement 3 times. The injection time is 30 s, the flushing time is 30 s, the peristaltic pump speed is 35 rpm, the nebulizing gas is argon, the nebulizing gas flow rate is 0.92 L / min, and the collision gas is helium, and the collision gas flow rate is 5 mL / min.

[0039] Preferably, in the disclosed embodiment, the microwave digestion instrument is: CEMMARS7 ultra-high pressure microwave digestion and extraction system; The instrument used in the inductively coupled plasma mass spectrometry is: PerkinElmer NexION 5000G inductively coupled plasma mass spectrometer.

[0040] Example: Preparation of instruments, reagents and materials: CEMMARS7 ultra-high pressure microwave digestion and extraction system; PerkinElmer NexION 5000G inductively coupled plasma mass spectrometer; EHD-16 acid removal device; Instrument calibration mixed standard solution No. 2 was purchased from PerkinElmer Co.; 1% high-grade pure dilute nitric acid, purchased from PerkinElmer Co.; 65.0%-68.0% concentrated nitric acid, purchased from Chengdu Kelong Chemical Co., Ltd.; Sample preparation: Accurately measure 100 μL of the raw material solution and place it in a digestion tank, place it in an acid removal instrument, heat and evaporate it to dryness, add 10 ml of concentrated nitric acid to the tank, seal it and place it in a microwave digestion instrument for microwave digestion, and after the digestion is completed, place it in an acid removal instrument for acid removal; The evaporation procedure was: 200 °C, 60 min; The digestion program is: power 1000W, temperature rise to 80℃ in 25min, keep warm for 10min; then temperature rise to 120℃ in 10min, keep warm for 10min; then temperature rise to 180℃ in 10min, keep warm for 10min, then temperature drop to 60℃ and stop the program; The acid removal procedure is: 100°C, 60min; After the acid removal is completed, cool to room temperature, transfer the solution from the digestion tank to a 50ml volumetric flask through a funnel, rinse the tank wall, tank cover and funnel with ultrapure water several times, transfer the cleaning solution to the volumetric flask, dilute to the scale line with ultrapure water, shake well, and obtain the preliminary sample solution; The preliminary sample solution was filtered through a 0.45 μm filter membrane, and the resulting solution was marked as the sample solution 1 to be tested. 5 ml of the sample solution 1 to be tested was taken and diluted to 50 ml with 1% high-grade pure dilute nitric acid. The resulting solution was marked as the sample solution 2 to be tested for detection by inductively coupled plasma mass spectrometry.

[0041] Configuration of standard solution: The multi-element mixed standard solution containing Ni with a concentration of 100 mg / mL was accurately diluted with 1% high-grade pure dilute nitric acid to 10 μg / L, 20 μg / L, and 50 μg / L standard solutions, which were named standard solution 1, standard solution 2, and standard solution 3, respectively. The standard solutions were prepared and used immediately, and were usually sealed and stored at -4°C. Determine instrument analysis conditions and establish sample measurement methods: Select the isotope of Ni 60 Ni, scanning mode: MS / MS; working mode: helium collision mode; number of scans: 20 times; number of repeated measurements: 3 times; marking method: linear zero crossing; standard sample settings: 10μg / L, 20μg / L, 50μg / L; injection time: 30s; flushing time: 30s; peristaltic pump speed: 35rpm; nebulizer gas: argon; nebulizer gas flow rate: 0.92L / min; collision gas: helium; collision gas flow rate: 5mL / min.

[0042] Under the analytical conditions, the established method was used to analyze the signal intensity of Ni in the blank solution and the standard solutions of 10 μg / L, 20 μg / L, and 50 μg / L, and the linear regression equation of the signal intensity y (cps) of Ni to its concentration x (μg / L) was obtained, and the standard curve equation and its linear correlation coefficient r were obtained; The signal intensity results of Ni element in blank sample and standard sample are shown in Table 1. The standard curve and relative error of Ni element are shown in Table 1. Figure 1 The linear regression equation is shown in Table 2: Table 1 Signal intensity results of Ni element in blank sample and standard sample

[0043] Table 2 Linear regression equation of Ni element

[0044] Testing of actual samples: In the present embodiment, 100 μL of raw material liquid is accurately measured, evaporated, acid digested, and after catching up with the acid, the digestion solution is fixed to 50 mL, filtered through a 0.45 μm filter membrane, and a sample solution 1 is obtained. 5 mL of the sample 1 is diluted to 50 mL to obtain a sample solution 2. The sample solution is analyzed using the built inductively coupled plasma mass spectrometry, and each sample is repeated three times to average the Ni element signal intensity in the sample solution, and then the Ni element standard curve established by the standard solution is used to determine the Ni element concentration in the sample solution. The Ni element signal intensity and concentration results obtained in the sample solution are shown in Table 3.

[0045] Table 3 Ni element signal intensity and concentration results in the sample solution to be tested

[0046] The relative standard deviations (RSDs) of the test results of the samples were all less than 2%. The Ni concentration in the test sample solution 1 was 10 times that in the test sample solution. The results were consistent with the facts, indicating that the quantitative results of the detected Ni element were accurate and reliable.

[0047] Finally, it should be noted that the above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic features of the present invention. Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is defined by the attached claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention. Any figure mark in the claims should not be regarded as limiting the claims involved.

[0048] In addition, it should be understood that although this specification is described in accordance with the implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation modes that can be understood by those skilled in the art. The above content is only to illustrate the technical idea of ​​the present invention, and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution according to the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A method for quantitative analysis of the metal element Ni in a complex matrix, characterized in that: The following steps are involved: Evaporating the liquid to be tested to dryness to obtain an evaporated sample; The evaporated sample was immersed in concentrated nitric acid and digested; The sample after digestion is subjected to acid removal, and then cooled and fixed to volume to obtain a preliminary sample solution, the preliminary sample solution is filtered and diluted with dilute nitric acid to obtain a sample solution to be tested; The helium collision mode of the inductively coupled plasma mass spectrometer was used for detection: blank solution and mixed standard solutions containing Ni element with different concentration gradients were used. The linear regression equation was established based on the signal intensity of Ni element and its corresponding concentration by using the external standard method, and the linear regression equation was used as the quantitative standard curve equation of Ni element; The sample solution to be tested is detected using the helium collision mode of the inductively coupled plasma mass spectrometer to obtain the signal intensity of the Ni element in the sample solution; Based on the signal intensity of the Ni element in the sample solution and combined with the quantitative standard curve equation, the concentration of the metal element Ni in the sample solution to be tested is obtained.

2. The method for quantitative analysis of the metal element Ni in a complex matrix according to claim 1, characterized in that: The liquid to be tested is a complex matrix, which is an alcohol substance. The alcohol substance contains a large amount of organic components that have adverse effects on the inorganic injection system of the inductively coupled plasma mass spectrometer and substances that are not suitable for direct microwave digestion.

3. The method for quantitative analysis of the metal element Ni in a complex matrix according to claim 1, characterized in that: The process of evaporating the liquid to be tested is as follows: The liquid to be tested was placed in a polytetrafluoroethylene digestion tank and subjected to an acid removal apparatus at 200°C for at least 60 min to obtain an evaporated sample.

4. The method for quantitative analysis of the metal element Ni in a complex matrix according to claim 1, characterized in that: The evaporated sample is immersed in concentrated nitric acid, left to stand for 15 minutes, sealed, and placed in a microwave digestion instrument for digestion; The nitric acid used in the digestion process in the microwave digestion instrument is 65.0%-68.0% high-grade pure concentrated nitric acid; The process of microwave digestion is: Heat to 80°C within 25 minutes and keep warm for 10 minutes; In the following 10 minutes, the temperature was raised to 120°C and kept at this temperature for 10 minutes; In the following 10 minutes, the temperature was raised to 180°C, kept at that temperature for 10 minutes, and then lowered to 60°C.

5. The method for quantitative analysis of the metal element Ni in a complex matrix according to claim 1, characterized in that: The process of removing acid from the sample after digestion is as follows: The digested sample was placed in an acid remover to remove acid. The temperature of the acid remover was 100° C. and lasted for at least 60 minutes. The preliminary sample solution was filtered through a 0.45 μm filter membrane.

6. The method for quantitative analysis of the metal element Ni in a complex matrix according to claim 1, characterized in that: The helium collision mode detection of the inductively coupled plasma mass spectrometer is: Use MS / MS scanning mode and helium KED working mode to perform kinetic energy identification to eliminate interference and select the isotopes of the metal elements. 60 Ni, and determine the content of the element to be tested based on the standard curve.

7. The method for quantitative analysis of the metal element Ni in a complex matrix according to claim 1, characterized in that: The mixed standard solutions containing Ni element with various concentration gradients are: The Ni-containing multi-element mixed standard solution with a concentration of 100 μg / mL was diluted to 10 μg / L, 20 μg / L and 50 μg / L with 1% high-grade pure dilute nitric acid. The diluted solutions were mixed standard solutions containing Ni elements with different concentration gradients.

8. The method for quantitative analysis of the metal element Ni in a complex matrix according to claim 1, characterized in that: The blank solution and the preliminary sample solution were prepared using 1% high-grade pure dilute nitric acid.

9. The method for quantitative analysis of the metal element Ni in a complex matrix according to claim 1, characterized in that: The detection conditions of the inductively coupled plasma mass spectrometer are: Scan 20 times and repeat the measurement 3 times. The injection time is 30 s, the flushing time is 30 s, the peristaltic pump speed is 35 rpm, the nebulizing gas is argon, the nebulizing gas flow rate is 0.92 L / min, and the collision gas is helium, and the collision gas flow rate is 5 mL / min.

10. The method for quantitative analysis of the metal element Ni in a complex matrix according to claim 1, characterized in that: The microwave digestion instrument used is: CEMMARS7 ultra-high pressure microwave digestion and extraction system; The instrument used in the inductively coupled plasma mass spectrometry is: PerkinElmer NexION 5000G inductively coupled plasma mass spectrometer.

Images