Portable detection device and method for high-selectivity trace scandium ions

Abstract

The invention discloses a portable detection device and method for high-selectivity trace scandium ions, and belongs to the technical field of rare earth metal ion detection. The detection device disclosed by the invention is simple in structure, convenient, accurate and low in cost according to fluorescence sensing detection. The detection method disclosed by the invention does not need to additionally synthesize an organic ligand and is environment-friendly; the fluorescence intensity of the complex is designed according to the principle that the fluorescence intensity of the complex is increased along with the increase of the concentration of Sc < 3 + > under the condition of an unsaturated complexing ratio, so that on-site real-time analysis of Sc < 3 + > can be realized, and the complex has the advantages of high sensitivity and high selectivity.

Description

Technical Field

[0001] The invention belongs to the technical field of rare earth metal ion detection, and in particular relates to a portable detection device and method for highly selective trace scandium ions. Background Art

[0002] Scandium (Sc), yttrium (Y) and the 15 lanthanide metals in the sixth period are collectively referred to as rare earth metals because of their similar physical and chemical properties. Rare earth elements are scarce, non-renewable, and widely used. They are strategic resources of the country, and China is the world's major supplier of rare earths. Among them, metal scandium and its compounds are widely used in emerging fields such as metallurgy, superconductors, supermagnetism, laser crystals, nuclear industry, aerospace, catalysis and solid fuel cells due to their unique electrical, optical and magnetic properties. As an important national strategic resource, the exploration and development of scandium ore plays a driving role in the development of my country's industry. At the same time, due to the large-scale separation, purification and processing of scandium ore, scandium in industrial waste and emissions will be released into the environment, which will have adverse effects on the ecosystem and human health, especially some potential hazards that have not yet been discovered. Therefore, the selective determination of trace scandium ions in the environment is of great significance. Although it is classified as a rare earth element, the total amount of metallic scandium on the earth is not rare. It just exists in various minerals in an extremely dispersed form. This is one of the reasons why scandium is difficult to detect.

[0003] Scandium is located in the third period, third subgroup, and has only one stable positive trivalent ion state (Sc 3+ ), currently used to detect Sc 3+ Traditional instrumental methods include atomic absorption spectroscopy, inductively coupled plasma mass spectrometry, inductively coupled plasma emission spectroscopy, neutron activation analysis, etc. These analytical strategies have certain limitations, such as the need for complex and expensive instruments, professional technicians, time-consuming sample pretreatment and cumbersome operations. In order to solve these problems, researchers have also developed some relatively convenient methods, such as spectrophotometry, fluorescence, electrochemistry, etc. Among these methods, fluorescence is achieved by synthesizing or selecting fluorescent chelating ligands with specific properties to bind to Sc 3+ The fluorescence intensity changes due to the action of the fluorescent method, and the fluorescence method has the characteristics of high sensitivity, especially the high signal-to-noise ratio of the open type fluorescence and low background signal, which can identify trace amounts of Sc 3+ However, most chelating ligands are not specific in their complexation with scandium and face the challenges of low selectivity and susceptibility to interference from other metal ions. Therefore, there is an urgent need to develop a highly selective and sensitive turn-on fluorescence strategy for the detection of scandium ions.

[0004] With the rapid development of science and technology, smartphones have become detection elements for various analytical methods, with the ability to store, analyze and share data, playing an important role in portable real-time detection. 3+ On-site determination of portable fluorescence sensing platform and detection method, so it is necessary to develop a fast and reliable portable fluorescence sensing platform and detection method to achieve Sc 3+ On-site testing. Summary of the invention

[0005] In view of the above-mentioned defects of the prior art, the present invention provides a portable detection device and method for highly selective trace scandium ions, which can realize the detection of Sc 3+ Simple, fast, on-site real-time analysis, simple and accurate, with a detection linear range of 0.04μM to 2.25μM and a detection limit of 0.02μM.

[0006] In a first aspect, the present invention provides a highly selective portable detection device for trace scandium ions, comprising a base and a housing movably disposed on the base;

[0007] The base is provided with a light source and a sample pool, and the light source is a 470nm LED lamp;

[0008] A 500nm filter and a photographing port are arranged above the sample pool, and the photographing port is arranged at the top of the housing;

[0009] The side wall of the housing is provided with a battery and a battery switch, which serve as a power source for the light source.

[0010] Furthermore, the base and the shell are made of black opaque resin and are manufactured by 3D printing.

[0011] Furthermore, the sample pool is cylindrical, with a diameter of 10 mm and a height of 8 mm; the sample pool carries a sample solution volume of 250 μL.

[0012] Furthermore, the parameters of the portable detection device for highly selective trace scandium ions include: the overall length of the device is 75mm, the width is 55mm, the height is 95mm, the LED light excitation wavelength is 470nm, the filter is 500nm, the quartz sample cell specifications are 8mm high and 10mm in diameter, and the power supply is two 1.5V dry batteries.

[0013] In a second aspect, the present invention provides a method for using the highly selective portable detection device for trace scandium ions according to any one of the first aspects, that is, a highly selective portable detection method for trace scandium ions, comprising the following steps:

[0014] Prepare scandium chloride mother solution, scandium chloride solutions with gradient concentrations, hydrochloric acid solution and calcein solution;

[0015] Prepare samples and measure the fluorescence intensity of each sample in turn using a fluorescence instrument, and draw a standard curve;

[0016] Assembling the portable detection device for highly selective trace scandium ions, turning on the light source, taking a picture of the solution after the sample reaction with a mobile phone camera, reading the data of the picture, and obtaining a linear regression equation;

[0017] The water sample to be tested is measured by the portable detection device for highly selective trace scandium ions, and then a standard solution is added to perform recovery measurement to obtain the spiked recovery rate of the method and the device to verify the accuracy;

[0018] The portable detection device for highly selective trace scandium ions is used to soak the ore sample to be tested in a hydrochloric acid solution, and the filtrate is filtered to react. The portable detection device for highly selective trace scandium ions is used to take photos and detect, so as to obtain the scandium ion concentration in the ore sample to be tested.

[0019] Furthermore, the concentration of the scandium chloride mother solution is 100 mmol / L, the gradient concentration scandium chloride solution is prepared by diluting the scandium chloride mother solution to 2-500 μmol / L, the pH value of the hydrochloric acid solution is 2.0, and the concentration of the calcein solution is 100 μmol / L.

[0020] Furthermore, the calcein solution is prepared by the following method:

[0021] A 10 mmol / L calcein solution was prepared and diluted with the hydrochloric acid solution to obtain a 100 μmol / L calcein solution.

[0022] Furthermore, the sample preparation includes: preparing 9 centrifuge tubes, adding 950 μL of hydrochloric acid solution and 50 μL of calcein solution to the first centrifuge tube as a blank control group, and adding 940 μL of hydrochloric acid solution, 50 μL of calcein solution and gradient concentrations of scandium chloride solution to the remaining 8 centrifuge tubes.

[0023] Furthermore, the water sample determination includes the following steps: filtering the water sample to be tested, adding a masking agent and then filtering the filtrate, adjusting the pH value to 2.0, adding a calcein solution to react, absorbing the reacted solution and placing it in a sample pool, taking a photo for detection, and obtaining the scandium ion concentration in the water sample to be tested.

[0024] Furthermore, after the water sample is measured, a standard solution is added for recovery measurement, comprising the following steps: 200 μmol / L scandium standard solution is mixed with hydrochloric acid solution and calcein solution in a volume ratio of 10:940:50, and then photographic detection is performed using the portable detection device for highly selective trace scandium ions.

[0025] Furthermore, the detection of the scandium ion concentration in the ore sample to be tested includes the following steps: crushing the ore sample to be tested, soaking it in a hydrochloric acid solution and ultrasonicating it, filtering to remove insoluble ore solids, adding a masking agent and filtering again, then adjusting the pH to 2.0, adding a calcein solution to react, aspirating the reacted solution into a sample pool, taking photos for detection, and obtaining the scandium ion concentration in the ore sample to be tested.

[0026] The above technical solution provided by the embodiment of the present application has at least the following advantages compared with the prior art:

[0027] 1. The present invention discloses a highly selective portable detection device for trace scandium ions, which has a simple structure and is easy to use. The combination with a smart phone sensing platform meets the requirements of on-site timely detection, and the detection cost is low.

[0028] 2. The present invention discloses a highly selective portable detection method for trace scandium ions, based on the principle that under simple acidic solution matrix conditions, the fluorescent chelated ligand indicator calcein as a Lewis base reacts with a Lewis acid (Sc 3+ ) can be specifically complexed, the complexation ratio is 2:1, Sc 3+ After complexing with calcein, the fluorescence of calcein, which was originally off, turns on and reacts to Sc 3+ Has unique selectivity. Therefore, the present invention is based on Sc 3+ The strong Lewis acid properties of Sc 3+ By complexing with the chelating ligand calcein, green fluorescence (optimal emission 500nm) was achieved from scratch at pH = 2.0 without the need for additional reagents and material synthesis, and the fluorescence intensity increased with the increase of scandium ions. The calcein fluorescent probe is very sensitive to Sc 3+ The detection is highly selective and sensitive, and can specifically detect trace amounts of Sc from 17 rare earth elements and common metal ions. 3+ At the same time, a 3D printed portable fluorescence sensing device (a highly selective portable detection device for trace scandium ions) combined with a smartphone was designed to convert fluorescence intensity into a color channel (G value), which is simple to operate, accurate and efficient.

[0029] 3. The highly selective portable detection method for trace scandium ions disclosed in the present invention needs to be carried out under the condition of HCl-H2O at pH = 2.0. Under this condition, the background fluorescence of calcein is low. 3+ After the fluorescence is turned on, the detection sensitivity is high. And the existing chelating ligand calcein can be used to achieve the detection purpose, without the need to synthesize other organic ligands, which is convenient, fast and environmentally friendly. Under this condition, the complexation of calcein with other metal ions is far less than that with Sc3+ The complexation is strong and highly selective, and is not affected by other rare earth metals. It can be used for portable fluorescence sensing detection of trace scandium ions. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0031] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0032] Figure 1 A schematic diagram of the principle of the portable detection of highly selective trace scandium ions according to the present invention;

[0033] Figure 2 Schematic diagram of a smartphone combined with a portable detection device for highly selective trace scandium ions;

[0034] Figure 3 A standard curve for the portable detection device for highly selective trace scandium ions;

[0035] Figure 4 This is a schematic structural diagram of a portable detection device for highly selective trace scandium ions provided in Example 1;

[0036] Figure 5 This is a flow chart for analyzing scandium ions in an ore sample in Example 2;

[0037] Figure 6 The standard curve measured by fluorescence instrument in Example 2;

[0038] Figure 7 Schematic diagram of measuring 11 parallel samples 11 times in a row using a portable detection device with high selectivity for trace scandium ions. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be described clearly and completely below. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0040] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in this application can be purchased from the market or prepared by existing methods.

[0041] The principles and features of the present invention are described below in conjunction with the examples, which are only used to explain the present invention and are not intended to limit the scope of the present invention. If no specific conditions are specified in the examples, the conditions are carried out according to conventional conditions or the conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments is not specified, they are all conventional products that can be purchased commercially.

[0042] In the following examples, hydrochloric acid was purchased from Chengdu Cologne Chemicals Co., Ltd. (Chengdu, China), calcein was purchased from Yuanye Biotechnology Co., Ltd. (Shanghai, China), and scandium chloride hexahydrate was purchased from Aladdin Biochemical Technology Co., Ltd. (Shanghai, China).

[0043] Example 1

[0044] like Figure 2 and Figure 4 As shown together, this embodiment provides a highly selective portable detection device for trace scandium ions, including a base and a housing that are movably connected, wherein a sample pool is arranged on the base, and the sample pool is used to load the sample to be tested, and is cylindrical. The sample pool is made of quartz sample pool, with a diameter of 10 mm, a height of 8 mm, and a solution volume of 250 μL.

[0045] The entire portable detection device is a box-shaped structure, 75mm long, 55mm wide, and 105mm high, made of black opaque resin completed by 3D printing.

[0046] A battery pack and a light source are arranged on the inner side wall of the housing, wherein the battery pack is controlled by a battery switch on the outer wall of the housing, and the battery provides power for the light source. The light source is a 470nm LED lamp, 3V and 3W.

[0047] At the upper end of the sample pool, a photographing port is provided at the top of the outer shell, and a 500nm filter is provided below the photographing port.

[0048] In order to cooperate with the use of the portable detection device for highly selective trace scandium ions, taking the Huawei P30 smartphone as an example, the phone camera was set to professional photo mode, ISO: 100, s: 1 / 60s.

[0049] Example 2

[0050] This embodiment provides a highly selective portable detection method for trace scandium ions. The samples to be tested are water samples and ore samples. The specific steps are as follows:

[0051] (1) Preparation of Scandium Chloride Mother Solution

[0052] Accurately weigh 0.02595 g of scandium chloride hexahydrate into a 2 mL centrifuge tube, add 1 mL of ultrapure water to dissolve it, and obtain a scandium chloride solution with a concentration of 100 mmol / L.

[0053] (2) Prepare a series of gradient scandium chloride solutions

[0054] The 100mmol / L scandium chloride solution is diluted step by step to the required concentration gradient (2μmol / L~500μmol / L) for use.

[0055] Among them, the concentrations include 0.04μmol / L, 0.1μmol / L, 0.2μmol / L, 0.5μmol / L, 1.0μmol / L, 1.5μmol / L, 2.0μmol / L, and 2.25μmol / L.

[0056] (3) Prepare pH = 2.0 hydrochloric acid solution

[0057] Prepare 100-fold and 1000-fold diluted concentrated hydrochloric acid and 150 mL of ultrapure water. Use a rubber-tipped dropper to gradually add the diluted hydrochloric acid into the ultrapure water in small amounts. Stir evenly. Use a pH meter to read the pH value of the solution. When the pH of the solution reaches 2.0, collect it for later use.

[0058] (4) Preparation of calcein solution

[0059] Accurately weigh 0.00623 g of calcein into a 2 mL centrifuge tube, add 1 mL of dimethyl sulfoxide to dissolve, to obtain a calcein solution with a concentration of 10 mmol / L, take 10 μL of the 10 mmol / L calcein solution and dilute it to 1000 μL with HCl-H2O at pH = 2.0 to obtain a 100 μmol / L calcein solution for use.

[0060] (5) Sample preparation

[0061] Prepare 9 centrifuge tubes, add 950μL of HCl-H2O and 50μL of calcein solution to the first one, add 940μL of HCl-H2O to the remaining 8 2mL centrifuge tubes, and then add 50μL of calcein solution. Finally, add 10μL of a series of gradient concentrations of scandium chloride solution to make the final concentration of scandium chloride 0.04μmol / L, 0.1μmol / L, 0.2μmol / L, 0.5μmol / L, 1.0μmol / L, 1.5μmol / L, 2.0μmol / L, 2.25μmol / L, and the total volume is 1mL. Three parallel samples were measured for each sample.

[0062] (6) Determine the standard curve using a fluorescence spectrophotometer

[0063] The fluorescence intensity of each solution in step (5) was measured in turn using a fluorescence spectrophotometer. The total volume of the solution was 1 mL. The parameters were set as follows: excitation wavelength 470 nm, slit 1 nm, and emission intensity at 500 nm. The fluorescence intensity of each group is shown in Table 1. A standard curve was drawn using origin. The ordinate was F / F0, where F was the fluorescence intensity in the presence of different concentrations of scandium ions, and F0 was the fluorescence intensity when the scandium ion concentration was 0. The standard curve was drawn as shown in Figure 6 shown.

[0064] Table 1

[0065]

[0066]

[0067] (7) Plotting a standard curve using the developed portable device

[0068] The developed portable fluorescence sensor device was used in combination with the color analysis software to read the G value of each solution in step (5) in turn. The LED lamp bead excitation wavelength was 470nm, the filter wavelength was 500nm, 250μL was taken and added to the quartz sample pool, the parameters of the mobile phone camera were fixed in professional mode, 3 parallel samples were measured, the Colorpicker software was opened for color analysis, and the G channel value in RGB was taken. The G values ​​of each group are shown in Table 2. The ΔG (G-G0, G is the value containing different concentrations of scandium chloride, and G0 is the blank value without scandium chloride) corresponding to the scandium chloride concentration was imported into the origin software, and the linear regression equation was obtained as shown in Table 3. The standard curve was drawn as shown in Table 3. Figure 3 shown.

[0069] Table 2

[0070]

[0071] Table 3

[0072] Target Linear regression equation Linear correlation coefficient Linear range (μmol / L) <![CDATA[Sc 3+ ]]> y=16.33x+1.66 0.99 0.02～2.25

[0073] (8) Stability test

[0074] At pH = 2.0, 11 parallel samples containing 5 μmol / L calcein and 2 μmol / L scandium chloride were measured 11 times in succession using a portable fluorescence sensor. The results are as follows: Figure 7 As shown, the specific operation is consistent with step (7).

[0075] (9) Water sample measurement

[0076] The collected water samples were filtered through a 0.22 μm microporous filter membrane to remove impurities, sealed with sealing glue, and stored in a refrigerator at 0-4°C for later use.

[0077] Water sample treatment process Figure 5 As shown (no need for steps 1 and 2), add 1mM S 2- (masking agent), and then filter with a 0.22μm filter head, collect the filtrate, and then use a portable pH meter to adjust to pH = 2.0, take 950μL of the supernatant, add 50μL of 100μmol / L calcein and mix evenly, use a pipette to draw 250μL of the prepared sample and add it to the quartz sample cell, cover the device to ensure that there is no interference from external light sources, place the mobile phone on the card slot of the portable device, set the camera to professional mode, turn on the excitation light power supply, take pictures, measure 3 parallel samples, and open the Color picker software for color analysis.

[0078] (10) Comparison with national standards

[0079] Inductively coupled plasma-mass spectrometry (ICP-MS / MS) was used to verify the accuracy of the developed portable fluorescence sensor. The instrument parameters were set as follows: power, 1550 W; auxiliary gas flow rate, 0.1 L min -1 ; Nebulizer gas flow rate, 0.1L·min -1 ; Detection mode, no gas; Three replicates were performed.

[0080] (11) Spike recovery experiment

[0081] Add standard solution for recovery determination (the purpose is to add a certain concentration of scandium standard for determination if scandium is not detected in the actual sample to determine the recovery rate in order to compare the accuracy of the method), add 940μL hydrochloric acid solution and 50μL calcein to three 2mL centrifuge tubes, and then add 10μL of 200μmol / L scandium standard solution to a total volume of 1mL. Mix well, take 250μL and add it to the quartz sample pool, measure 3 parallel samples, open the Color picker software for color analysis, and the results are shown in Table 4. Neither method detected the scandium content in the lake. The spike recovery experiment showed that the recovery rate was 90-114%, which can be used for the detection of scandium in real water samples.

[0082] Table 4

[0083]

[0084] Note: a The data are shown as mean ± standard deviation of three measurements, and ND means not measured.

[0085] (12) Testing of ore samples

[0086] like Figure 5As shown, the ore sample was soaked in 50 mL of pH = 2.0 hydrochloric acid solution and ultrasonicated for 80 min. The remaining steps were consistent with (9). The analysis results are shown in Table 5. Both methods did not detect the scandium content in quartzite, kaolinite and manganese ore, but both detected scandium in bauxite. The detection value of this method was 0.71 μmol / L, and the detection value of the national standard method was 0.67 μmol / L. F = 4.24 <F 0.05,5,2 =19.3, indicating that there is no significant difference in the precision of the two groups of data, t = 1.91 <t 0.05,2 =4.30, there is no significant difference between the two methods, the spike recovery is between 81-117%, the results show that this method can be used for the detection of rare earth ores in real ore samples. The national standard method is consistent with step (10).

[0087] Table 5

[0088]

[0089] a Mean ± standard deviation of three measurements; ND means not determined.

[0090] Figure 5 In the figure, 1 indicates the step of crushing the ore sample, 2 indicates the step of soaking in hydrochloric acid, 3 indicates the step of adding a masking agent, 4 indicates filtering and collecting the filtrate, 5 indicates adjusting the pH to 2.0, 6 indicates taking a photo with a mobile phone after adding calcein, and 7 indicates the process of software analysis.

[0091] In summary, the present invention can use the industrially produced fluorescent chelate ligand indicator calcein as a Lewis base and a strong Lewis acid Sc under simple acidic solution matrix conditions (i.e., a hydrochloric acid solution with a pH of 2.0) to react with the strong Lewis acid Sc. 3+ Specific complexation, resulting in a complexation ratio of 2:1 (calcein: Sc 3+ ) complex, Sc 3+ After complexing with calcein, the fluorescence of calcein, which was originally off, turns on and reacts to Sc 3+ It has unique selectivity, its principle is as follows Figure 1 shown.

[0092] Under the condition of unsaturated complex ratio, the fluorescence intensity of the complex increases with Sc 3+ The portable fluorescent sensor device of Example 1 of the present invention (i.e., a highly selective portable detection device for trace scandium ions) is designed using a smart phone detection device. It is simple and accurate, with a detection linear range of 0.04μM to 2.25μM and a detection limit of 0.02μM, which meets the requirements of on-site timely detection (POCT). The proposed method does not require additional synthesis of organic ligands, is low-cost, and is environmentally friendly. It can achieve the detection of Sc 3+Simple, fast and on-site real-time analysis.

[0093] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.

Claims

1. A highly selective portable detection device for trace scandium ions, characterized in that: It comprises a base and a shell movably arranged on the base; The base is provided with a light source and a sample pool, and the light source is a 470nm LED lamp; A 500nm filter and a photographing port are arranged above the sample pool, and the photographing port is arranged at the top of the housing; The side wall of the housing is provided with a battery and a battery switch, which serve as a power source for the light source.

2. The portable detection device for highly selective trace scandium ions according to claim 1, characterized in that: The base and the shell are made of black opaque resin and are manufactured by 3D printing.

3. The portable detection device for highly selective trace scandium ions according to claim 1, characterized in that: The sample pool is cylindrical, with a diameter of 10 mm and a height of 8 mm; the sample pool carries a sample solution volume of 250 μL.

4. A highly selective portable detection method for trace scandium ions, based on the highly selective portable detection device for trace scandium ions according to any one of claims 1 to 3, characterized in that: The following steps are involved: Prepare scandium chloride mother solution, scandium chloride solutions with gradient concentrations, hydrochloric acid solution and calcein solution; Assemble the portable detection device for highly selective trace scandium ions, turn on the light source, take a picture of the solution after the sample reaction with a mobile phone camera, read the data of the picture, and obtain a linear regression equation; A masking agent is added to the water sample or the ore sample to be tested, and the supernatant is filtered and adjusted to a pH value of 2.0, and then the calcein solution is added to react, and the highly selective trace scandium ion portable detection device is used to photograph the solution after the reaction to obtain the scandium ion concentration in the water sample or the ore sample to be tested.

5. The portable detection method for highly selective trace scandium ions according to claim 4, characterized in that: The concentration of the scandium chloride mother solution is 100mmol / L, the gradient concentration scandium chloride solution is prepared by diluting the scandium chloride mother solution to 2-500μmol / L, the pH value of the hydrochloric acid solution is 2.0, and the concentration of the calcein solution is 100μmol / L.

6. The portable detection method for highly selective trace scandium ions according to claim 5, characterized in that: The calcein solution is prepared by the following method: A 10 mmol / L calcein solution was prepared and diluted with the hydrochloric acid solution with a pH of 2.0 to obtain a 100 μmol / L calcein solution.

7. The portable detection method for highly selective trace scandium ions according to claim 4, characterized in that: The sample reaction process includes: preparing 9 centrifuge tubes, adding 950 μL of hydrochloric acid solution and 50 μL of calcein solution to the first centrifuge tube, and adding 940 μL of hydrochloric acid solution, 50 μL of calcein solution and 10 μL of scandium chloride solution with gradient concentrations to the remaining 8 centrifuge tubes.

8. The portable detection method for highly selective trace scandium ions according to claim 4, characterized in that: Before obtaining the linear regression equation using the portable fluorescence sensor device, the fluorescence intensity of the solution after the sample reaction is first measured using a fluorescence meter, and a standard curve of the standard sample is obtained to indicate feasibility.

9. The portable detection method for highly selective trace scandium ions according to claim 4, characterized in that: The detection of the scandium ion concentration in the water sample to be tested includes the following steps: after conventional pretreatment (filtration) of the water sample to be tested, a masking agent is added and then the filtrate is filtered, the pH value is adjusted to 2.0, a calcein solution is added for reaction, the solution after the reaction is drawn into a sample pool, and a photo is taken for detection to obtain the scandium ion concentration in the water sample to be tested.

10. The portable detection method for trace scandium ions with high selectivity according to claim 4, characterized in that: The detection of the scandium ion concentration in the ore sample to be tested includes the following steps: crushing the ore sample to be tested, soaking it in a hydrochloric acid solution and ultrasonicating it, filtering the filtrate, adding a masking agent, and then filtering it, adjusting the pH to 2.0, adding a calcein solution to react, absorbing the reacted solution and placing it in a sample pool, taking a photo for detection, and obtaining the scandium ion concentration in the ore sample to be tested.

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