Separation method and detection method for trace Se and As in multi-metal sample

Abstract

The invention belongs to the technical field of atomic spectrum analysis and detection, and particularly relates to a method for separating trace Se and As in a multi-metal sample and a method for rapidly detecting the trace Se and As in the multi-metal sample based on atomic absorption spectrometry. According to the method for separating trace Se and As in the multi-metal sample, a miniature cation chromatographic column is adopted, especially a zero empty bed volume leaching technology is adopted, the column flow rate can be as high as several milliliters per minute, the elution volume is only 1-2 milliliters, the separation effect is close to 100%, only 2-3 minutes are needed for collecting As or Se flowing through a column bed, the separation speed is high, and the separation efficiency is high. And the determination result is accurate and reliable.

Description

Technical Field

[0001] This invention belongs to the field of atomic spectroscopy analysis and detection technology, specifically relating to a method for separating trace Se and As in multi-metal samples and a method for rapidly detecting trace Se and As in multi-metal samples based on atomic absorption spectroscopy. Background Technology

[0002] In recent years, separation techniques such as high-performance liquid chromatography (HPLC), gas chromatography (GC), and capillary electrophoresis (CE), coupled with detectors such as hydride generation atomic fluorescence spectrometry (HG-AFS), hydride generation atomic absorption spectrometry (HG-AAS), and inductively coupled plasma mass spectrometry (ICP-MS), have been widely used for the detection of sample components or speciation analysis. For determining trace amounts of Se and As in samples, hydride AAS or AFS spectroscopy is typically used. While hydride atomic absorption spectrometry or atomic fluorescence spectrometry offers high sensitivity for Se and As determination, the matrix components significantly interfere with samples with high metal ion concentrations, making direct measurement of the sample solution impossible. Especially when the content of certain coexisting elements is high, the analytical data obtained by these methods deviates significantly from the actual values, or even cannot be performed. Taking the determination of trace Se content in geological samples as an example, interference from multiple elements is present, especially in polymetallic samples, where even the addition of ferric ions is ineffective. Therefore, how to accurately determine trace Se and As in polymetallic ores has remained an unsolved problem.

[0003] In the traditional detection of trace Se and As in multimetallic samples, a significant challenge lies in the separation and enrichment of Se or As. Currently, there is no effective method for separating and enriching Se. For separating As from copper sulfate or basic copper sulfate, the traditional method involves precipitating copper ions (e.g., using NH4CNS or NaOH), allowing the precipitate to clarify, and then measuring the As in the supernatant. However, traditional precipitation methods suffer from incomplete precipitation or adsorption effects, and are cumbersome, time-consuming, and labor-intensive. Therefore, there is an urgent need to develop faster and more accurate separation methods.

[0004] Significant breakthroughs were achieved in the research and application of high-performance microchromatographic columns at the end of the last century. In particular, the use of zero-empty-bed-volume elution technology allows for column flow rates as high as several milliliters per minute, with elution volumes of only 1-2 ml and separation efficiency approaching 100%. The field anticipates utilizing high-performance microchromatographic column technology to achieve the separation and detection of trace amounts of Se and As in multi-metal samples. Summary of the Invention

[0005] Therefore, the technical problem to be solved by the present invention is to provide a method for separating trace amounts of Se and As in a multi-metal sample. The method utilizes a high-efficiency microchromatographic column, which can separate Se or As from interfering components within minutes and accurately determine the content of Se or As.

[0006] The second technical problem to be solved by the present invention is to provide a method for rapid detection of trace amounts of Se and As in multi-metal samples based on atomic absorption spectrometry;

[0007] The third technical problem to be solved by the present invention is to provide the separation and detection methods of trace Se and As in polymetallic samples and their application in the detection of trace Se and As in polymetallic samples, especially in the field of detection of trace Se and As in polymetallic samples.

[0008] To solve the above-mentioned technical problems, the present invention provides a method for separating trace amounts of Se and As in a multi-metal sample, comprising the following steps:

[0009] (1) Packing and preparing a miniature cation chromatography column;

[0010] (2) The micro cation chromatography column was eluted using zero-empty-bed volume elution technology;

[0011] (3) Prepare the test solution and inject it into the micro cation chromatography column for separation.

[0012] Specifically, in the method for separating trace amounts of Se and As in the multi-metal sample, in step (1), the micro cation chromatography column includes DOWEX 50W cation exchange resin.

[0013] Specifically, in the method for separating trace Se and As in the multi-metal sample, the assembly step in step (1) includes: taking the DOWEX 50W cation exchange resin, rinsing it with water, taking the resin that is below a 100-mesh sieve and above a 120-mesh sieve, and loading it into the chromatographic column using a negative pressure wet method, thus obtaining the product.

[0014] Specifically, in the method for separating trace Se and As in the multi-metal sample, in step (1), the filling height of the DOWEX50W cation exchange resin is 5-10 cm, preferably 6-8 cm.

[0015] Specifically, in the method for separating trace Se and As in the multi-metal sample, step (2) includes the zero-empty-bed volume elution technique:

[0016] When the packed micro cation chromatography column is passed through the column bed with acid, water or test solution, a small-volume intermittent elution method is used. That is, the amount loaded onto the column each time is small, and between each two elutions, negative pressure is required to remove the liquid between the resin particles so that the empty bed volume approaches zero.

[0017] Specifically, in the method for separating trace Se and As in the multi-metal sample, before loading the test solution onto the column in step (3), the column needs to be rinsed with 1+1 HCl. After the HCl has drained, the column bed is rinsed with pure water until the residual acid is neutral, so that the column has been regenerated.

[0018] Specifically, in the method for separating trace amounts of Se and As in the multimetallic sample, in step (3), the concentration of HCl in the test solution is no greater than 2%. The separation step includes: placing the receiving tube for collecting the column liquid at the effluent end of the chromatographic column, controlling the negative pressure of the elution to 0.1-0.2 MPa, injecting 1-2 ml of the test solution into the regenerated micro cation chromatography column, after the test solution passes through the column, evacuating the column bed solution, and rinsing the resin with a small amount of pure water; the collected effluent and water rinse are used to determine Se and As, respectively.

[0019] Specifically, the method for separating trace Se and As in the multi-metal sample, step (3) further includes the step of regenerating the micro cation chromatography column after each loading of the test solution onto the column;

[0020] The regeneration step includes rinsing the micro cation chromatography column sequentially with acid and pure water.

[0021] The present invention also discloses a method for detecting trace Se and As in a multi-metal sample, comprising the steps of separating trace Se and As in the multi-metal sample according to the method, and the steps of determining the content of Se and As in the separated sample by atomic absorption spectrometry.

[0022] In this application, the atomic absorption spectrometry method can be a method known in the prior art. As an exemplary method, the content of Se or As can be determined according to the test conditions for hydride generation, and the acidity of the test solution is controlled to be 10% HCl and the concentration of KBH4 is 1.5%-2%. The test solution for determining Se needs to be reduced to tetravalent in HCl of not less than 50% beforehand, and the test solution for determining As should be pre-reduced to trivalent by adding 5% thiourea-5% Vc and letting it stand for 30 minutes.

[0023] The present invention also discloses the application of the separation method of trace Se and As in the multi-metal sample or the detection method of trace Se and As in the multi-metal sample in elemental analysis and detection, especially in the field of trace Se and As analysis and detection.

[0024] The method for separating trace amounts of Se and As in multi-metal samples described in this invention employs a micro-cationic column. Since both Se and As exist in solution as anions, while most other metal ions are cations, when the sample solution is passed through the micro-cationic column, Se and As flow through the column bed, while the cations are firmly adsorbed by the resin. In particular, the zero-empty-bed-volume elution technique allows for a flow rate as high as several milliliters per minute, with an elution volume of only 1-2 ml, achieving nearly 100% separation efficiency. Collecting As or Se from the column bed takes only 2-3 minutes. During column regeneration, less than 2 ml of metal cations are eluted from the column bed using 1+1 HCl. This method not only provides rapid separation but also accurate and reliable results.

[0025] The method for detecting trace Se and As in multimetallic samples described in this invention employs a high-efficiency cation microchromatographic column and an anionic SeO4 column. 2- (or SeO3) 2- ) or AsO4 2- As the chromatographic column flows through the resin, the metal cations are adsorbed. The most prominent advantage of the micro-column using zero-empty-bed volume elution technology lies in its high efficiency, namely, fast column loading rate, large adsorption capacity, near 100% separation efficiency, and small elution volume. In particular, the cations enter the column bed in a laminar flow state, resulting in a large adsorption capacity. The column will not leak before the resin reaches saturation. Se or As in the elution is completely separated from the metal cations in the resin bed within minutes, enabling rapid and accurate determination of trace amounts of Se or As in the sample. Attached Figure Description

[0026] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings, wherein...

[0027] Figure 1 This is a schematic diagram of the high-efficiency microchromatographic column structure and operating system described in this invention;

[0028] Figure 2 This is a schematic diagram of the adsorbed Cu ions (A) and the regenerated resin bed (B) in Example 2.

[0029] Figure 3 In Example 3, the effect of acid concentration in the solution on the Se recovery rate was investigated.

[0030] Figure 4 The effect of HCl concentration on Cu ion elution rate in Example 3;

[0031] Figure 5 The elution curve of Cu ions in Example 3;

[0032] Figure 6 This is the standard curve for 0-20 ng / ml As in Example 4;

[0033] Figure 7 This represents the absorption signal of As in the test solution in Example 4;

[0034] The attached figures are labeled as follows: 1-Liquid inlet funnel, 2-Sand core, 3-Cation resin, 4-Filter cotton, 5-Micro switch, 6-Air pump. Detailed Implementation

[0035] Example 1

[0036] This embodiment describes the preparation of the required micro cation chromatography column according to the following steps:

[0037] (1) After washing the uniformly sized DOWEX 50W cationic resin with water to remove floating matter, sieve it and take the resin that is below the 100-mesh sieve and above the 120-mesh sieve. Pack it into the chromatographic column by negative pressure wet method, with a packing height of about 7cm. Cover the top with a little glass wool.

[0038] (2) After preparing the chromatographic column, rinse it with pure water and remove the liquid between the resin particles under negative pressure. Then rinse the column bed with 5 ml of 1+1 HCl at 1 ml intervals. After each rinse, remove all the solution in the column bed (i.e., the empty bed volume is zero). Finally, rinse the column bed with pure water until the residual acid is near neutral. At this point, the chromatographic column has been regenerated and can be used for the separation and enrichment of the test solution.

[0039] Appendix Figure 1 Images (a)-(c) are schematic diagrams of the high-efficiency microchromatographic column structure described in this invention, which can operate with one or more columns simultaneously. (See attached diagram.) Figure 1 The microchromatographic column described in (a) has an inner diameter of 2.5-3 mm in a quartz glass tube. The column has an inlet funnel 1 at the top and a sintered core 2 at the bottom, with a length of approximately 10 cm. The quartz glass tube is filled with cation exchange resin 3 and filter cotton 4, and the bottom is controlled by a microswitch 5.

[0040] As attached Figure 1 In step (b), regardless of whether a single or multiple chromatographic columns are used, the columns must first be connected to a vacuum system. The miniature column is placed in a system equipped with a vacuum pump 6. Under a certain negative pressure, the required solution is intermittently injected into the column in small volumes. After the solution has drained, the solution between the stationary phase particles is evacuated until the empty volume of the column bed approaches zero, and then the solution is injected again. This method first regenerates the column bed by rinsing it with acid, then by rinsing it with water until the residual acid is neutral. Then, a test solution with an HCl concentration not exceeding 2% is injected into the regenerated column. The collected column buffer and water eluent are used to determine Se or As.

[0041] High-performance microchromatographic columns are characterized by their small column diameter, fine stationary phase particles, and uniform packing; they operate under negative pressure, meaning they are connected to a negative pressure system (as shown in the attached image). Figure 1 The specific operating method is the opposite of that of conventional chromatographic columns. Before loading the column, the column bed is filled with air. Whether for adsorption or elution, small-volume intermittent loading is used. After the solution has completely drained, the solution in the column bed is completely drained (the empty bed volume is zero). Currently, the chromatographic columns used include extraction columns, adsorption columns, and ion exchange columns, which are used for the separation and enrichment of 30 elements, including U, Th, Sc, Cr, Re, Au, Pb, Cd, Tl, and Li. The following example of this invention utilizes a cation exchange column to adsorb polymetallic ions and determine the concentration of Se or As in the effluent. (See attached...) Figure 1 (c) is a schematic diagram of multiple microchromatograms being operated simultaneously.

[0042] In this embodiment, when separating trace amounts of Se or As in multi-metal samples using the miniature cation exchange column, the negative pressure for elution should be controlled at approximately 0.1 MPa. The column bed should be eluted with 1+1 HCl to regenerate the column, and then rinsed with pure water until neutral. An eluent collection tube should be placed at the end of the column beforehand. Once the required negative pressure is achieved, 1-2 ml of the prepared test solution should be injected into the miniature cation exchange column. After the test solution passes through the column, the column bed solution should be completely removed, and any test solution that may be entrained in the resin should be rinsed with 0.2 ml of pure water. The collected eluent and water wash can be used to determine Se or As. The used column should be rinsed with 1+1 HCl to elute the metal ions adsorbed on the resin, and then rinsed with water to remove residual acid, thus regenerating the column for reuse in the separation of the next sample.

[0043] Example 2

[0044] This example demonstrates the high efficiency of microchromatographic columns by using a cation exchange column to adsorb CuSO4.

[0045] In the separation operation of Example 2, the efficiency of the microchromatographic column was investigated using colored CuSO4. When 100 mg of CuSO4 was passed through the column, the blue region was found to occupy only the upper layer of the resin bed (as shown in the attached image). Figure 2 The color boundary is clearly visible, indicating that the resin adsorption of CuSO4 is far from saturated, and the lower layer of the resin bed can still adsorb more CuSO4. After loading the column with copper sulfate solution, the column bed is eluted with 0.2 ml of HCl each time, and the copper ions are rapidly eluted. After elution with 0.4 ml of HCl, the solution at the end of the column bed is the darkest, indicating that the concentration of eluted Cu ions has reached its maximum. After elution with 0.8 ml of HCl, the adsorbed Cu ions in the resin bed have been eluted, indicating that only a very small amount of eluent is needed to completely elute the copper adsorbed on the column. In actual work, the column bed is eluted with 1-2 ml of HCl, and then the resin bed is eluted with a small amount of water to remove excess HCl, and the column is regenerated (see attached). Figure 2 (See section B). This embodiment is also suitable for other adsorbed cations, such as those used to determine trace amounts of Se in multimetallic samples.

[0046] Example 3: Determination of Trace Se in Polymetallic Ores

[0047] In this embodiment, the micro cation microchromatographic column was prepared according to the method in Example 1, and the effect of acid concentration in the test solution on the Se recovery rate was investigated.

[0048] Se standard solutions were prepared in HCl, HNO3, or aqua regia of different concentrations. Following the column operation procedure in Example 1, the solutions were passed through the column, and the column bed was rinsed with a small amount of purified water. The concentration of Se in the solution flowing through the column bed was measured, and the Se recovery percentage was calculated as shown in the appendix. Figure 3 .

[0049] Appendix Figure 2 The curves showed that 2% concentrations of the three acids did not affect the complete recovery of Se. Since the determination of Se needs to be carried out in HCl, 2% HCl was used as the loading solution. In 2% HCl, a mixture of 100 μg each of Fe, Co, Ni, Cu, Pb, Zn ions and 10 μg of Se was passed through the chromatographic column, and the column bed was eluted with 0.2 mL of water each time. No added cations were found in the eluent, and all 10 μg of Se was collected in the eluent and the 0.2 mL water eluent.

[0050] The elution effect on cations was further investigated using the selected HCl concentration (2%). 100 μg of Cu ions were used for the experiment; after loading the column, it was eluted with 1-6 mol / L HCl, and six elution curves were plotted as shown in the attached figure. Figure 4 The results showed that the elution effect increased with increasing acid concentration. When the HCl concentration reached 4-6 mol / L, four 0.2 ml syringes were sufficient to completely elute the Cu ions on the column.

[0051] The elution curves of Cu ions were further investigated by eluting the column with 8 mol / L HNO3 and 6 mol / L HCl, respectively. The resulting elution curves are shown below. Figure 5 Clearly, HCl is more effective than HNO3 in completely eluting Cu ions, and only 1 ml is needed.

[0052] Further investigation was conducted on the permissible levels of interfering ions. Trace Se in geological samples was determined using the hydride generation method. The interference from various transition elements was significantly more severe than that from other elements. Column chromatography tests were performed on 13 ions, and the removal efficiencies are shown in Table 1 below.

[0053] Table 1. Removal rate of coexisting ions / %

[0054] Element name Amount added / μg Removal rate / % Fe 10000 100 Co 1000 100 Ni 1000 100 Cu 1000 100 Pb 1000 100 Zn 1000 100 Cr 1000 92 Cd 1000 97 Mo 100 100 Sn 100 100 Bi 100 100 Au 100 100 Ag 100 90

[0055] The data in the table above show that more than 90% of the samples contained coexisting metal ions, indicating that the microchromatographic column using the empty bed volume elution technique has high efficiency in separating polymetallic ions and provides a necessary prerequisite for determining trace Se in polymetallic ores.

[0056] Based on the determined conditions and parameters, the Se content of multimetallic complex samples was tested. Copper, lead, nickel, molybdenum, tin, and arsenic ores were selected, and 0.2-0.5 g of sample was weighed and placed in a 50 ml 4F beaker. HNO3, HF, and perchloric acid were added. The mixture was heated at low temperature until concentrated perchloric acid fumes were emitted. After the volume was reduced to a small volume, concentrated hydrochloric acid (at least 50%) was added, and the mixture was boiled for 3 minutes to reduce the hexavalent Se to the tetravalent Se. After cooling, the solution was diluted with water to 25 ml (with the acidity controlled to be less than 3%). 1-2 ml of the solution was loaded onto a column, and the column buffer and eluent were collected. 5 mg of Fe was added. 3+ For the ions, add HCl to bring the volume to 20%, dilute with water to 5 ml, shake well, and then determine the concentration of Se using hydride atomic absorption or atomic fluorescence spectrometry. Each sample was tested three times, and the standard deviation was calculated. The results measured using atomic fluorescence spectrometry are listed in Table 2 below.

[0057] Table 2. Determination results of Se in polymetallic ores (μg / g)

[0058]

[0059] As can be seen, all 24 samples in the table are national standard substances. The data shows that after separation by microchromatographic column, the content of Se in the samples not only matches the recommended value, but also the range of uncertainty is significantly reduced. Among them, the original recommended values ​​of GSO-2, GSO-5 and GSM-4 were uncertain, but after testing by this method, definite analytical results were obtained.

[0060] As can be seen, this embodiment utilizes a high-efficiency microchromatographic column to separate interfering elements, ultimately solving the long-standing problem of atomic fluorescence spectrometry's inability to determine trace Se in polymetallic ores. The method is characterized by high efficiency, low cost, and accurate data, while also offering fast analysis speed, simple operation, and easy wide-ranging application for the determination of trace Se in various samples.

[0061] Example 4: Determination of trace As in high-purity copper sulfate

[0062] This embodiment uses hydrogenation atomic absorption or atomic fluorescence spectrometry to determine As. For chemical products such as copper sulfate (including basic copper sulfate or copper chloride, etc.), the concentration of Cu ions is too high, and the concentration of As cannot be determined without separation.

[0063] For the separation of the main metal Cu ions from trace As, the most common method is to convert Cu ions into a precipitate. NH4CNS or NaOH can be used as precipitating reagents, or Na2S2O3 can be used to precipitate Cu ions as Cu2S2O3. However, the precipitation method is cumbersome, and the precipitate itself has an adsorption effect, making it not only time-consuming and labor-intensive, but also often yielding unreliable results.

[0064] This embodiment uses a φ3mm cation exchange microcolumn, packed according to the method described in Example 1. The permissible amount of CuSO4 is at least greater than 100mg. When the sample volume is 0.5g, 1 / 5 or 1 / 10 of the sample solution is passed through the column. The eluent is analyzed by ICP-MS, and no Cu signal is detected, indicating that Cu has been completely adsorbed onto the column. The collected eluent and a small amount of water eluent are used for As determination.

[0065] In this embodiment, since the efficiency of As recovery by the microchromatographic column is nearly 100%, the analytical results can be directly calculated using a standard curve. 0-20 ng / ml As standard solutions were prepared, and the absorbance of each solution was measured under the conditions of hydrogenation generation atomic absorption spectrometry. The resulting standard curve is shown below. Figure 6 The correlation coefficient of the obtained curve is 0.999999.

[0066] Weigh approximately 0.5 g of CuSO4 or basic copper sulfate, dissolve in water (a small amount of HCl needs to be added for basic copper sulfate), and dilute to a certain volume. Take 1-2 ml of each and pass it through a regenerated chromatographic column. Collect the eluent (and eluent), control the HCl concentration at 10%, reduce with Vc-thiourea, and determine by hydrogen atomization.

[0067] Weigh 0.5230 g of copper sulfate, dissolve it in water and dilute to 10 ml. Take 2 ml and load it onto the column. Collect the eluent and water eluent. Determine the concentration of As in 10 ml of the test solution. The signal spectrum is shown below. Figure 7 The test result was 3.662 ng / ml, meaning the As content in high-purity copper sulfate was 0.35 μg / g. Taking 5 ml of the test solution (18.31 ng), adding 20 ng of standard As to 7 ml, and determining the result yielded 39.697 ng, with a recovery rate of 106.9%.

[0068] Weigh 0.5292 g of basic copper sulfate, dissolve it in 1.5 ml of 1+1 HCl, and dilute with water to 14 ml. A 1 ml aliquot is loaded onto a column, and the eluent and water wash are collected in 20 ml. The concentration of As is determined to be 13.87 ng / ml, and the As content in the basic copper sulfate is calculated to be 7.338 μg / g. 2 ml of this solution (27.74 ng As) is taken, and 50 ng of standard solution is added. The concentration is measured in 5 ml, and the measured value is 15.31 ng / ml, with a recovery of 76.55 ng, resulting in a recovery rate of 97.62%. The same determination is performed on both samples, and the recoveries are 101.6% and 103.6%, respectively. The average recoveries are 104.1% and 100.6%.

[0069] The above test results show that the use of a high-efficiency micro cation chromatography column has a large adsorption capacity, is not prone to leakage, and can quickly separate a large number of copper ions. Compared with the precipitation method, it is more complete, faster, less labor-intensive, has lower testing costs, and provides more accurate data, and can be widely promoted and applied.

[0070] After column regeneration, the separation of the next sample can proceed. For a large number of samples, using a multi-column micro-column operating system for simultaneous separation and enrichment demonstrates its superior speed and data accuracy.

[0071] In summary, the method for separating trace amounts of Se and As in multi-metal samples described in this invention employs a micro-cationic column. Since both Se and As exist in solution as anions, while most other metal ions are cations, when the sample solution is passed through the micro-cationic column, Se and As flow through the column bed, while the cations are firmly adsorbed by the resin. In particular, the zero-empty-bed-volume elution technique allows for a flow rate as high as several milliliters per minute, with an elution volume of only 1-2 ml, achieving nearly 100% separation efficiency. Collecting As or Se from the column bed takes only 2-3 minutes, and the elution volume of metal cations in the column bed is less than 2 ml. This method not only provides rapid separation but also accurate and reliable results.

[0072] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for the separation of trace amounts of Se and As in a multi-metal sample, characterized by, It comprises the following steps: (1) packing a micro cationic chromatographic column; (2) using zero empty bed volume elution technique to elute the micro cationic chromatographic column; (3) preparing a test solution and injecting it into the micro cationic chromatographic column for separation.

2. The method for separating trace Se and As in a multi-metal sample according to claim 1, characterized in that, In the step (1), the micro cationic chromatographic column comprises DOWEX 50W cationic resin.

3. The method for separating trace Se and As in multi-metal sample according to claim 2, characterized in that, In the step (1), the packing step comprises: taking the DOWEX 50W cationic resin after water rinsing, taking the resin under 100 mesh and above 120 mesh, and packing it into the chromatographic column by negative pressure wet method.

4. The method for separating trace Se and As in the multi-metal sample according to claim 3, characterized in that, In the step (1), the packing height of the DOWEX 50W cationic resin is 5-10 cm, preferably 6-8 cm.

5. The method according to any one of claims 1 to 4, wherein the method is used for separating trace Se and As in a multi-metal sample. In the step (2), the zero empty bed volume elution technique comprises: The packed micro cationic chromatographic column is eluted with pure water, and the liquid between the resin particles is extracted by negative pressure; Then, the column bed is eluted with acid solution at intervals, and the solution in the column bed is extracted after each elution to make the empty bed volume tend to zero; Continue to elute the residual acid in the column bed with pure water until it is nearly neutral, and the micro cationic chromatographic column is obtained.

6. The method according to any one of claims 1 to 5, wherein the method is used for separating trace Se and As in a multi-metal sample. In the step (3), the test solution controls the HCl concentration to be not more than 2%.

7. The method according to any one of claims 1 to 6, wherein the method is used for separating trace Se and As in a multi-metal sample. In the step (3), the separation step comprises: placing a receiving tube for collecting the column liquid at the outlet end of the chromatographic column, controlling the negative pressure for air extraction elution to be 0.1-0.2 Mpa, injecting 1-2 ml of the test solution into the micro cationic chromatographic column, extracting the column bed solution after the test solution passes through the column, and rinsing the resin with pure water; the effluent and the water rinsing liquid are collected for determination of Se and As, respectively.

8. The method according to claim 7, wherein the method is characterized by, In the step (3), it further comprises a regeneration step of the micro cationic chromatographic column; The regeneration step comprises the steps of sequentially eluting the micro cationic chromatographic column with acid solution and pure water.

9. A method for detecting trace amounts of Se and As in a multi-metal sample, characterized in that, It comprises the steps of separating trace Se and As in a multi-metal sample according to the method of any one of claims 1-8, and determining the contents of Se and As in the separated sample by atomic absorption spectrometry.

10. The use of the method for separating trace Se and As in a multi-metal sample according to any one of claims 1-8 or the method for detecting trace Se and As in a multi-metal sample according to claim 9 in the field of element analysis, especially trace Se and As analysis and detection.

Images