Metal ion enrichment material, enrichment column and enrichment method

Abstract

The present invention relates to the field of environmental catalysis, and in particular to a kind of enrichment material, enrichment column and enrichment method of metal ions, the enrichment material is used to enrich the stable metal ions and active intermediate valence metal ions in the sample; the enrichment material includes an enrichment column filler of a thiol compound bonded modified organosilicon derivative; wherein the metal ions include one or more of the ionic states of Al, Mn, Ni, Ag, Cu, Zn, Sn, Sb, Hg, Pb, Cd, Ca, Cr, and Fe, and the thiol compound includes one of 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, and 3-mercaptopropylmethyldimethoxysilane. The metal ion enrichment material provided by the present invention has a mild material usage, good enrichment and preservation ability for some metal forms that are more easily converted, can well enrich and detect ultra-trace unstable intermediate valence metal ions, and is widely used, and can preserve and detect the forms of metal ions in various solutions including environmental water bodies and biological fluids.

Description

Technical Field

[0001] The present invention relates to the field of environmental analysis, and in particular to a metal ion enrichment material, an enrichment column and an enrichment method. Background Art

[0002] In recent years, with the rapid development of industry, a variety of metal mines have been mined, and large amounts of metal-containing wastewater have been discharged into natural water bodies. When harmful metals enter the human body and other organisms, they can denature certain proteins and inactivate enzymes, leading to varying degrees of poisoning. The toxicity of a metal is related to its type, concentration, form, and valence state. Therefore, the detection of metal forms and concentrations in natural water bodies is crucial for the management and prevention of metal pollution.

[0003] Due to the complex matrices of aquatic environments (river, lake, and seawater), and the fact that metal concentrations in natural water are often at ultratrace levels, the conventional method involves transporting large quantities of natural water back to the laboratory for enrichment and processing before testing. However, collecting large quantities of natural water requires the use of large amounts of strong acid, and this can pose safety issues during transportation. The traditional method for on-site enrichment of metal ions is extraction. Extraction exploits the different solubilities of solutes in immiscible solvents to concentrate the solute in the target solvent. Depending on the solvent type, these methods can be broadly categorized as liquid-liquid extraction, solid-liquid extraction, and turbidity point extraction. Compared to other extraction methods, solid-phase extraction (SPE) is a convenient and easy-to-use method for on-site enrichment of metal ions. Common SPE methods can be categorized by extraction mechanism: ion exchange extraction, electrostatic adsorption extraction, and reversed-phase solid-phase extraction. The anion and cation exchange columns used in ion exchange extraction cannot enrich metals in all sample matrices due to their specific adsorption of ions. The solid-phase matrices used in graphene and carbon nanotube extraction methods, which utilize electrostatic adsorption, are expensive and complex to prepare. The reversed-phase solid-phase extraction method can only specifically enrich certain organic metals, but cannot enrich all metals.

[0004] Therefore, the on-site enrichment methods in the prior art are unable to achieve on-site enrichment of multiple metal ions and have poor universality. Summary of the Invention

[0005] Based on this, the present invention proposes an ultra-trace metal ion enrichment material, enrichment column and enrichment method, which can enrich a variety of metal ions in natural water on-site and maintain the form and concentration of the enriched metal ions. It can also obtain qualitative and quantitative data by eluting and detecting the enriched metals.

[0006] According to one aspect of the present invention, a metal ion enrichment material is provided for enriching stable metal ions and active intermediate valence metal ions in a sample;

[0007] The above-mentioned enrichment material includes an enrichment column filler of a thiol compound bonded to a modified organosilicon derivative;

[0008] Among them, the above-mentioned metal ions include one or more ionic states of Al, Mn, Ni, Ag, Cu, Zn, Sn, Sb, Hg, Pb, Cd, Ca, Cr, and Fe.

[0009] According to an embodiment of the present invention, the mercapto compound includes one of 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane and 3-mercaptopropylmethyldimethoxysilane.

[0010] According to an embodiment of the present invention, wherein the intermediate valence metal ions include monovalent mercury ions;

[0011] The above-mentioned stable metal ions include one or more of divalent mercury ions, methylmercury or ethylmercury.

[0012] According to an embodiment of the present invention, the content of the mercapto compound accounts for 30%-100% of the total amount of the material.

[0013] According to an embodiment of the present invention, the concentration of the metal ions in the sample containing the metal ions is 1 ppt to 100 ppt.

[0014] According to another aspect of the present invention, there is provided an enrichment column prepared using the above-mentioned enrichment material as a filler, wherein the enrichment column is used for enriching stable metal ions and active intermediate-valence metal ions;

[0015] Among them, the above-mentioned metal ions include one or more ionic states of Al, Mn, Ni, Ag, Cu, Zn, Sn, Sb, Hg, Pb, Cd, Ca, Cr, and Fe.

[0016] According to one aspect of the present invention, a method for enriching metal ions using the above-mentioned enrichment column is provided, comprising: passing a solution containing metal ions into the above-mentioned enrichment column to enrich stable metal ions and active intermediate-valence metal ions.

[0017] According to an embodiment of the present invention, the present invention further includes:

[0018] Utilizing an eluent to elute the enrichment column enriched with metal ions;

[0019] The eluted metal ions are detected.

[0020] According to an embodiment of the present invention, the eluent includes a thiol solution, wherein the thiol solution includes a thiol-containing elution solute and a solvent.

[0021] According to an embodiment of the present invention, the concentration of the thiol-containing elution solute is 1% (v / v).

[0022] It can be seen from the above technical solutions that the metal ion enrichment material, enrichment column and enrichment method provided by the present invention have the following beneficial effects:

[0023] The metal ion enrichment material provided by the present invention is suitable for on-site investigation of water samples containing various metal ions (Al, Mn, Ni, Ag, Cu, Zn, Sn, Sb, Hg, Pb, Cd, Ca, Cr, Fe). It is not limited by the matrix of the water sample to be enriched and is applicable to seawater, river water, lake water, etc. It is convenient, easy to operate, fast and efficient.

[0024] The metal ion enrichment material provided by the present invention has good enrichment and preservation capabilities for some metal forms that are more easily transformed due to its mild material usage. Taking monovalent mercury, an unstable intermediate valence state of metallic mercury, as an example, compared with the aminothiol column, the metal ion enrichment material provided by the present invention can well enrich and detect ultra-trace monovalent mercury ions.

[0025] It is convenient for complete qualitative and quantitative detection of enriched metal ions and accurate understanding of the concentrations of various metal ions in natural water.

[0026] The metal ion enrichment material provided by the present invention can preserve and detect the form of metal ions. Taking mercury as an example, this method can well enrich, preserve, and separate and detect ultra-trace amounts of divalent mercury and methylmercury in natural water and biological fluids.

[0027] The metal ion enrichment material provided by the present invention can be used repeatedly and has good repeatability. The relative standard deviation (RSD) of five repeated injections of multiple metals is (5.22%).

[0028] The metal ion enrichment material provided by the present invention has a high loading capacity and can not only enrich ultra-trace metals in natural water, but also enrich high-concentration metals (the highest concentration can be as high as 1 ppb) in polluted water bodies. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a graph showing the results of enriching and storing mercury in different forms for ten days and then eluting the mercury using an enrichment column according to an embodiment of the present invention;

[0030] Figure 2 1 is a comparison chart of the enrichment detection results of trace monovalent mercury ions by the enrichment column and the aminothiol column in the embodiment of the present invention. DETAILED DESCRIPTION

[0031] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings.

[0032] The traditional method for on-site enrichment of metal ions is extraction. Extraction exploits the different solubilities of solutes in immiscible solvents to enrich the solute in the target solvent. Depending on the solvent type, extraction can be broadly categorized into liquid-liquid extraction, solid-liquid extraction, and cloud point extraction. Compared to other extraction methods, solid-phase extraction (SPE) is a convenient and easy-to-use method for on-site enrichment of metal ions. Common SPE methods can be categorized by extraction mechanism as ion exchange, electrostatic adsorption, and reversed-phase solid-phase extraction (RPSE). The anion and cation exchange columns used in ion exchange extraction cannot enrich metals in all sample matrices due to their specific adsorption of ions. The solid-phase matrices used in graphene and carbon nanotube extraction methods, which utilize electrostatic adsorption, are expensive and complex to prepare. Reverse-phase SPE can only specifically enrich certain organic metals and cannot enrich all metals. Based on RPSE, this method investigates the use of modified RPSE columns for the enrichment of multiple metals commonly found in aquatic environments.

[0033] On this basis, optimization was carried out to obtain enrichment materials that can be used specifically for the enrichment of multiple metal ions, which has good prospects for the detection of the forms and concentrations of multiple metals in natural water.

[0034] According to the general inventive concept of one aspect of the present invention, a metal ion enrichment material is provided for enriching stable metal ions and active intermediate valence metal ions in a sample;

[0035] The enrichment material includes an enrichment column filler of a thiol compound bonded to a modified organosilicon derivative;

[0036] Among them, the metal ions include one or more ionic states of Al, Mn, Ni, Ag, Cu, Zn, Sn, Sb, Hg, Pb, Cd, Ca, Cr, and Fe.

[0037] The metal ion enrichment material provided by the present invention is suitable for on-site investigation of water samples containing various metal ions (Al, Mn, Ni, Ag, Cu, Zn, Sn, Sb, Hg, Pb, Cd, Ca, Cr, Fe). It is not limited by the matrix of the water sample to be enriched and is applicable to seawater, river water, lake water, etc. It is convenient, easy to operate, fast and efficient.

[0038] The metal ion enrichment material provided by the present invention has good enrichment and preservation capabilities for some metal forms that are more easily transformed due to its mild material usage. Taking monovalent mercury, an unstable intermediate valence state of metallic mercury, as an example, compared with the aminothiol column, the metal ion enrichment material provided by the present invention can well enrich and detect ultra-trace monovalent mercury ions.

[0039] It is convenient for complete qualitative and quantitative detection of enriched metal ions and accurate understanding of the concentrations of various metal ions in natural water.

[0040] The metal ion enrichment material provided by the present invention can preserve and detect the form of metal ions. Taking mercury as an example, this method can well enrich and preserve ultra-trace divalent mercury and methylmercury in natural water and then separate and detect them.

[0041] The metal ion enrichment material provided by the present invention can enrich and detect the forms of heavy metal ions in various sample matrices. This method can well enrich, preserve, and separate and detect divalent mercury, methylmercury, and ethylmercury in natural water and biological fluids.

[0042] The metal ion enrichment material provided by the present invention can be used repeatedly and has good repeatability. The relative standard deviation (RSD) of five repeated injections of multiple metals is (5.22%).

[0043] The metal ion enrichment material provided by the present invention has a high loading capacity and can not only enrich ultra-trace metals in natural water, but also enrich high-concentration metals (the maximum concentration can be as high as (1000ppt)) in polluted water bodies.

[0044] According to an embodiment of the present invention, the mercapto compound includes one of 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane and 3-mercaptopropylmethyldimethoxysilane.

[0045] According to an embodiment of the present invention, the enrichment material can be prepared by a self-assembly method of an organosilicon derivative, driven by the in-situ formation of polysilicon oxide, which connects to the surface silanol (-SiOH) groups via silicon-oxygen bonds (Si-O-Si).

[0046] The use of hydrophobic reagents containing sulfur bonds or sulfhydryl-modified non-polar reversed-phase media can effectively enrich a variety of ultra-trace metal ions in natural water.

[0047] According to an embodiment of the present invention, wherein the intermediate valence metal ions include monovalent mercury ions;

[0048] The stable metal ions include one or more of divalent mercury ions, methylmercury or ethylmercury.

[0049] According to Lewis's acid-base electron theory, all complexes are acid-base adducts. The strength of the bond between the center and the ligand is related to the hardness or softness of the acid and base. Soft acids are cations with large radii, low charges, and easily deformable electron clouds, such as Hg. 2+ 、Co 2+ 、Ni 2+ 、Cu 2+ , Pt 2+ Etc. Soft bases have low electronegativity to atoms, are easy to donate electrons, and are easily deformed, such as I -1 The acid-base combination conforms to the principle of "soft favors soft, hard favors hard", and most metals can be firmly combined with -SH. Therefore, the present invention adopts the principle of combining metals with thiol groups to design the enrichment material.

[0050] According to an embodiment of the present invention, the content of the mercapto compound accounts for 30%-100% of the total amount of the material.

[0051] According to an embodiment of the present invention, the content of the thiol compound can account for 30%, 40%, 50%, 60%, 70%, 80%, 90%, or 100% of the total amount of the material, among which the preferred content of the thiol compound is 90%-100%.

[0052] According to an embodiment of the present invention, the concentration of metal ions in the sample containing metal ions is 1 ppt to 100 ppt.

[0053] According to an embodiment of the present invention, the enrichment content of the enrichment material for common metal ions (Al, Mn, Ni, Ag, Cu, Zn, Sn, Sb, Hg, Pb, Cd, Ca, Cr, Fe) in natural water is in the range of (1ppt-100ppt).

[0054] According to another aspect of the present invention, there is provided an enrichment column prepared using an enrichment material as a filler, the enrichment column being used for enriching stable metal ions and active intermediate valence metal ions;

[0055] Among them, the metal ions include one or more ionic states of Al, Mn, Ni, Ag, Cu, Zn, Sn, Sb, Hg, Pb, Cd, Ca, Cr, and Fe.

[0056] The present invention optimizes the enrichment column by adopting a new enrichment material, so that the enrichment column provided by the present invention can not only enrich metal ions, but also stably preserve the concentration and form of the metal ions unchanged; after being transported back to the laboratory, the metal ions can be quickly eluted, separated and detected. To a large extent, the enrichment column can be used to conduct complete qualitative and quantitative analysis and detection of the forms and concentrations of various metal ions in natural water.

[0057] The enrichment material and enrichment column provided by the present invention greatly improve the accuracy and universality of detection, and can achieve complete qualitative and quantitative detection of various metal ions (Al, Mn, Ni, Cu, Zn, Sn, Sb, Hg, Pb, Cd) in natural water of various matrices (river water, sea water, lake water, etc.); in terms of on-site enrichment, the enrichment column provided by the present invention is highly feasible and convenient, easy to use and easy to carry.

[0058] According to another aspect of the present invention, a method for enriching metal ions in an enrichment column is provided, comprising: passing a solution containing metal ions into the enrichment column to enrich stable metal ions and active intermediate valence metal ions.

[0059] The enriched water samples in this method do not require pretreatment, eliminate the use of acids or organic reagents, and are more environmentally friendly.

[0060] In terms of laboratory testing, the enrichment method using the enrichment column of the present invention can ensure the stability of metal form and concentration, and the elution process is simple and easy to operate; in terms of detection limit, the method can achieve a lower detection limit.

[0061] According to the embodiment of the present invention, the enrichment column can be used for enrichment at room temperature and low temperature, and can maintain a good enrichment effect, and can stably maintain the form and concentration of the metal.

[0062] According to an embodiment of the present invention, the preferred enrichment, transportation and storage temperature of the enrichment column is 4°C.

[0063] According to an embodiment of the present invention, the present invention further includes:

[0064] Utilizing an eluent to elute the enrichment column enriched with metal ions;

[0065] The eluted metal ions are detected.

[0066] According to embodiments of the present invention, the enrichment column can be eluted online or offline. The detection limit for online elution is very low (0.04 ppt), while the detection limit for offline elution is 3 ppt. Online elution requires an online enrichment device, which is relatively cumbersome. The offline elution process is relatively simple and easy.

[0067] According to an embodiment of the present invention, the eluent comprises a thiol solution, wherein the thiol solution comprises an eluting solute containing a thiol group and a solvent.

[0068] According to an embodiment of the present invention, the concentration of the thiol-containing elution solute comprises 1% (v / v).

[0069] The technical solutions of the present invention are described in detail below through preferred embodiments. It should be noted that the specific embodiments below are only for illustration and are not intended to limit the present invention.

[0070] Example 1: Preparation of enrichment column samples.

[0071] Step 1: Use a solvent to disperse silica gel and prepare a solution of 3-mercaptopropyltriethoxysilane.

[0072] Step 2: Place silica gel in a three-necked flask, heat to 120-140°C, add 3-mercaptopropyltriethoxysilane solution, and stir to react. Utilizing the self-assembly properties of silane, the thiol groups are bonded to the silica gel matrix.

[0073] Step 3: After the reaction is completed, the reaction solution is dried and then filled into the column to obtain the enrichment column sample.

[0074] Comparative Example 1: Preparation of reverse-phase solid-phase extraction column.

[0075] The reversed-phase solid-phase extraction column used in this comparative example is a dithizone-modified C18 reversed-phase solid-phase extraction column.

[0076] Step 1: Dissolve a certain amount of dithizone in 25% ammonia water, add formic acid to adjust the pH to 9.0, and add deionized water to make up to volume.

[0077] Step 2: Fifty percent of the dithizone is passed through a C18 enrichment column, so that excess dithizone is retained on the extraction column enrichment column to obtain a C18 column sample.

[0078] Comparative Example 2: Preparation of aminothiol column.

[0079] Step 1: Weigh 1-3 g of dicyclohexylcarbodiimide and hydroxybenzotriazole into a dichloromethane solution, then add 1 ml of 3-mercaptopropionic acid and stir at room temperature for one hour.

[0080] Step 2: Add 0.5-1 g of amino-silica to the solution and stir at room temperature for 24 hours.

[0081] Step 3: After the reaction is completed, the product is washed with dichloromethane, ethyl acetate, formic acid, ultrapure water and methanol in sequence, and the final product is collected after centrifugation.

[0082] Step 4: Dry the obtained product and fill it into a column to obtain an aminothiol-enriched column sample.

[0083] Example 2: Detection of enrichment column performance.

[0084] 1. Enrichment of various metal ions by enrichment column:

[0085] In this embodiment, the enrichment column of the thiol compound modified organosilicon derivative prepared in Example 1 and the dithizone modified C prepared in Comparative Example 1 were investigated. 18 The columns were used to enrich various metal ions.

[0086] Step 1: Prepare 10 ng L using deionized water -1 A mixed solution containing multiple elements such as Al, Mn, Ni, Ag, Cu, Zn, In, Sn, Sb, Hg, Pb, Cd, Ca, Cr, and Fe.

[0087] Step 2: Use a 50mL syringe to slowly pass 50mL of the mixed standard solution through the two enrichment columns to enrich the metals.

[0088] Step 3: Seal the enrichment column to obtain the enrichment column sample and C 18 Column samples.

[0089] 2. Elution detection of enriched metal ions:

[0090] The enrichment column sample and C 18 The metal ions that have been enriched in the column sample are eluted as follows:

[0091] Offline elution detection of enriched metal ions:

[0092] S1: Prepare mercaptoethanol at a concentration of 20%.

[0093] S2: Use 20% mercaptoethanol solution to enrich the column sample and C 18 The column sample was eluted and the eluate was collected.

[0094] S3: The eluate is subjected to metal ion concentration detection.

[0095] Online elution detection of enriched metal ions:

[0096] S1: Prepare 1% mercaptoethanol solution.

[0097] S2: Use a liquid phase pump to use 1% mercaptoethanol as the mobile phase to enrich the column sample and C 18 The column sample was eluted online and the metal concentration was detected.

[0098] Enrichment column sample and C 18 The elution results of the column samples in the online and offline modes are shown in Table 1.

[0099] Table 1. Enrichment column samples and C 18 Elution results of column samples in online and offline modes

[0100]

[0101] In this experiment, two enrichment column elution experiments were performed: online and offline elution. The enrichment column provided by the present invention can successfully collect a variety of metal ions under two different elution modes. The detection limit of online elution is very low (0.04 ppt). The detection limit of offline elution is 3 ppt. Online elution requires the use of an online enrichment device, which is relatively cumbersome. The offline elution process is relatively simple and easy.

[0102] 3. Preservation capacity of the enrichment column for various metal ions:

[0103] The two groups of enrichment column samples were stored at room temperature (25°C) and low temperature (4°C) for 10 days respectively.

[0104] The enrichment columns enriched with various metals were eluted under normal temperature and low temperature conditions, and the metal enrichment and preservation efficiency is shown in Table 2.

[0105] Table 2. Storage capacity of enrichment column samples at room temperature (25°C) and low temperature (4°C)

[0106]

[0107]

[0108] This experiment was designed to optimize the storage conditions for enriched metals in the enrichment column. In the aforementioned experiments, two enrichment columns were used to study the morphology and concentration of the enriched metals at both room temperature (25°C) and low temperature (4°C). The enrichment column provided by the present invention exhibited relatively good preservation capabilities at both room temperature and low temperature. Ultimately, low temperature (4°C) was selected as the optimal storage and transportation condition for the enriched metals.

[0109] 4. The enrichment column's ability to enrich and preserve polymorphic metals (taking mercury as an example):

[0110] Figure 1 This is a graph showing the results of eluting mercury in different forms after enrichment and storage for ten days using an enrichment column according to an embodiment of the present invention.

[0111] Prepare low concentration standard solutions (10 ng L) of different forms of mercury (methylmercury, divalent mercury and ethylmercury) -1 ).

[0112] The low-concentration mercury standard solution was passed through the enrichment column of the thiol compound-bonded modified organosilicon derivative prepared in Example 1, and the low-concentration mercury in different forms was enriched and preserved using the enrichment column.

[0113] The enrichment column was sealed and stored at low temperature for ten days.

[0114] The enrichment column that has been enriched with metal ions is eluted offline, and the eluate is collected to detect the form and concentration of mercury.

[0115] The results are as follows Figure 1 As shown, the enrichment column provided by the present invention preserves the form of metal ions and can be used to enrich and preserve ultra-trace amounts of divalent mercury and methylmercury in natural water for subsequent separation and detection.

[0116] 5. Enrichment and preservation capacity of the enrichment column for metal ions in multi-matrix natural water:

[0117] Collect natural water samples (river water, sea water, lake water), use the natural water samples as the base, and prepare 10n gL -1 Samples containing multiple elements such as Al, Mn, Ni, Ag, Zn, Hg, Pb, Cd, Ca, Cr, and Fe.

[0118] 50 mL of the sample was passed through the enrichment column of the thiol compound-bonded modified organosilicon derivative prepared in Example 1 using a 50 mL syringe, so that various metal ions were enriched on the enrichment column.

[0119] The enrichment column was sealed and stored at low temperature for ten days.

[0120] The enrichment column that has been enriched with metal ions was eluted offline, and the metal enrichment and preservation efficiency is shown in Table 3.

[0121] Table 3. Enrichment capacity of enrichment column samples in river water, sea water, and lake water

[0122]

[0123] As shown in Table 3, the enrichment column provided by the present invention can enrich a variety of metal ions (Al, Mn, Ni, Ag, Zn, Hg, Pb, Cd, Ca, Cr, Fe) and is not limited by the matrix of the water sample to be enriched. It is suitable for seawater, river water, lake water, etc.

[0124] 6. Loading capacity of enrichment column:

[0125] Prepare samples containing various elements such as Al, Mn, Ni, Ag, Cu, Zn, Hg, Cd, Ca, Cr, and Fe at different concentrations. The concentration gradients are 1 ng L -1 、10ng L -1 , and 100 ng L -1 .

[0126] 50 mL of samples with different concentration gradients were passed through four groups of enrichment columns of thiol-bonded modified organosilicon derivatives using a 50 mL syringe, so that a variety of metal ions were enriched on the enrichment column.

[0127] The enrichment column that has been enriched with metal ions was eluted offline, and the metal enrichment and preservation efficiency is shown in Table 4.

[0128] Table 4. Enrichment and preservation effects of the enrichment column on metals of different concentrations

[0129]

[0130] As can be seen from Table 4, when the concentration of heavy metal ions increases step by step (1 ppt-100 ppt), the enrichment ability of the thiol column for multiple metal ions does not decrease. Therefore, the enrichment column provided by the present invention can tolerate the enrichment and elution of heavy metal ions with different concentration gradients and has a strong loading capacity for heavy metals.

[0131] 7. Enrichment efficiency of unstable monovalent mercuric ions by different thiol columns:

[0132] Figure 2 1 is a comparison chart of the enrichment detection results of trace monovalent mercury ions by the enrichment column and the aminothiol column in the embodiment of the present invention.

[0133] In this embodiment, the enrichment effect of the thiol compound bonded modified organosilicon derivative enrichment column prepared in Example 1 and the aminothiol column prepared in Comparative Example 3 on monovalent mercuric ions was explored.

[0134] The concentration was 50 ng L -1 monovalent mercury solution.

[0135] Step 1: Prepare 50 ng L using deionized water -1 of Hg(I) solution.

[0136] Step 2: Use a 10 mL syringe to slowly pass 5 mL of Hg(I) solution through two enrichment columns for enrichment.

[0137] Step 3: Seal the enrichment column to obtain two enrichment column samples: an enrichment column and an aminothiol column.

[0138] Step 4: Use online elution to elute the enriched monovalent mercury in the enrichment column sample and the aminothiol column sample respectively. The steps are as follows:

[0139] S1: Prepare 1% mercaptoethanol solution.

[0140] S2: Using a liquid phase pump, 1% mercaptoethanol was used as the mobile phase to elute the enrichment column sample and the aminomercapto column sample online and detect the metal concentration. Figure 2 shown.

[0141] The aminothiol column may have both amino and thiol groups, and its chelating effect with metal ions is relatively strong. Ordinary eluents are difficult to elute the enriched metal ions, and extreme eluents such as strong acids or strong bases are required, which complicates the method and is not conducive to environmental protection.

[0142] The enrichment column (propylmercapto column) provided by the present invention uses simple materials, and the chelation with metal ions and the elution with thiol-containing reagents can just achieve the enrichment and elution of monovalent mercuric ions without affecting the stability of monovalent mercuric ions, without the need to use extreme eluents, and is beneficial to environmental protection.

[0143] 8. Enrichment efficiency of different thiol columns for various metal ions:

[0144] In this embodiment, the enrichment effect of the thiol compound bonded modified organosilicon derivative enrichment column prepared in Example 1 and the aminothiol column prepared in Comparative Example 3 on various metal ions was explored.

[0145] Use deionized water to prepare 10 ng L -1 A mixed solution containing multiple elements such as Al, Mn, Ni, Ag, Cu, Zn, Sn, Sb, Hg, Pb, Cd, Ca, Cr, and Fe.

[0146] Step 1: Prepare 10 ng L using deionized water -1 A mixed solution containing multiple elements such as Al, Mn, Ni, Ag, Cu, Zn, Sn, Sb, Hg, Pb, Cd, Ca, Cr, and Fe.

[0147] Step 2: Use a 10 mL syringe to slowly pass 5 mL of the multi-element mixed solution through two enrichment columns for enrichment.

[0148] Step 3: Seal the enrichment column to obtain two enrichment column samples: an enrichment column and an aminothiol column.

[0149] Step 4: Use online elution to elute the various metal elements enriched in the enrichment column sample and the aminothiol column sample respectively. The steps are as follows:

[0150] S1: Prepare 1% mercaptoethanol solution.

[0151] S2: Using a liquid phase pump and 1% mercaptoethanol as the mobile phase, the enrichment column sample and the aminomercapto column sample were eluted online and the metal concentration was detected. The results are shown in Table 5.

[0152] Table 5. Enrichment effect of propylthiol column and aminothiol column on various metal ions (100ppt)

[0153]

[0154] The results in Table 5 show that, compared to the aminothiol column, the enrichment material of the present invention can effectively enrich and detect a variety of metal ions. Therefore, the enrichment material and enrichment column of the present invention can not only enrich metals without changing their morphology, but also achieve the simultaneous enrichment of multiple metal ions (Al, Mn, Ni, Ag, Cu, Zn, Sn, Sb, Hg, Pb, Cd, Ca, Cr, Fe) using mercury as an example (intermediate valence unstable metal ion and stable metal ion).

[0155] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for enriching metal ions, wherein the metal ions include one or more of the ionic states of Al, Mn, Ni, Ag, Cu, Zn, Sn, Sb, Hg, Pb, Cd, Ca, Cr, and Fe, characterized in that: The following steps are involved: Using an enrichment column whose filler is a thiol compound bonded modified organosilicon derivative, wherein the thiol compound includes one of 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, and 3-mercaptopropylmethyldimethoxysilane; Passing a sample containing metal ions into the enrichment column to enrich stable metal ions and active intermediate-valence metal ions, wherein the stable metal ions include one or more of divalent mercury ions, methylmercury or ethylmercury, and the intermediate-valence metal ions include monovalent mercury ions; Online elution of the enrichment column enriched with metal ions is performed using an eluent, wherein the eluent includes a thiol solution, the thiol solution includes a thiol-containing elution solute and a solvent, the concentration of the thiol-containing elution solute is 1% (v / v), and the thiol-containing elution solute is mercaptoethanol; The eluted metal ions are detected.

2. The method according to claim 1, characterized in that The concentration of the metal ions in the sample containing the metal ions is 1 ppt to 100 ppt.

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