ECL detector for detecting trace cesium ions and application thereof

Abstract

The invention discloses an ECL detector for detecting trace cesium ions and application of the ECL detector, the ECL detector comprises a working electrode, a reference electrode, a counter electrode, an electrolyte and a photomultiplier, and a poly-o-phenylenediamine film with a porous structure is deposited on the surface of the working electrode. The ECL detector for detecting trace cesium ions provided by the invention has the advantages of ultralow detection limit, high selectivity and field visual detection, and can be successfully applied to visual and accurate determination of trace cesium in various environmental samples such as fresh water, salt water and the like and various animal samples (fishes, arthropods and mollusks).

Description

Technical Field

[0001] The invention relates to the technical field of cesium ion detection, and in particular to an ECL detector for detecting trace cesium ions and an application thereof. Background Art

[0002] As a high-yield nuclear fission product, cesium-137 is considered one of the most important radioactive pollutants due to its long half-life (30.2 years) and obvious radiotoxicity. Due to its chemical properties similar to potassium, cesium ions (Cs + ) can participate in potassium ions (K + ) and is retained in soft tissues, which can cause significant radiation damage. In addition to potential Cs-137 contamination of drinking water, the contamination of animals, especially aquatic products (such as fish, shrimp, crab, etc.) also needs attention because Cs-137 accumulates in their edible parts, such as muscle tissue. Since the content of cesium in environmental samples is very low (such as the order of ng / L in fresh water), the accurate and rapid determination of cesium has obvious significance in the field of environment and public health.

[0003] So far, a variety of cesium detection technologies have been studied, including inductively coupled plasma mass spectrometry, X-ray fluorescence spectroscopy, fluorescence sensors, electrochemical sensors, colorimetry, etc. The detection limits (LOD) of currently known fluorescence, colorimetric, and electrochemical sensors are often between nM and μM, which cannot meet the requirements of trace cesium monitoring in the environment. Although ICP-MS shows good selectivity and sensitivity in metal ion detection (LOD: ng / L level), it does not provide good salt tolerance and simplified pretreatment. Considering the trace amount of Cs in freshwater, it is not suitable for the detection of trace amounts of Cs in freshwater. + The concentration is in the order of pg / L, and the LOD of ICP-MS still cannot meet the requirements for monitoring trace cesium in the environment. Summary of the invention

[0004] In order to solve the above technical problems, the purpose of the present invention is to provide an ECL detector for detecting trace cesium ions and its application. The ECL detector for detecting trace cesium ions has ultra-high sensitivity and selectivity, and can be used for accurate and rapid determination of trace cesium in actual environmental samples. The ECL detector can be successfully applied to the visualization and accurate determination of trace cesium in various environmental samples such as fresh water and salt water, as well as various animal samples (fish, arthropods, and mollusks).

[0005] A further object of the present invention is to provide an electrochemiluminescence detection instrument based on screen-printed electrodes, which can be used for ultra-sensitive, highly selective, accurate and rapid monitoring of trace cesium after the fixed technology is commercialized, which is of great significance in the fields of environment and nuclear safety.

[0006] The above object of the present invention is achieved through the following technical solutions:

[0007] The first aspect of the present invention provides a method for detecting trace amounts of cesium ions (Cs + ) comprises an ECL detector, comprising a working electrode, a reference electrode, a counter electrode, an electrolyte and a photomultiplier tube, wherein a porous poly-o-phenylenediamine film is deposited on the surface of the working electrode.

[0008] Furthermore, a working electrode having a porous poly-o-phenylenediamine film deposited on its surface is prepared by the following method: o-phenylenediamine and a cesium salt are dissolved in a solvent to obtain a mixed solution; the mixed solution is used as an electrolyte to deposit a poly-o-phenylenediamine film on the electrode surface by an electrochemical deposition method; and cesium ions in the poly-o-phenylenediamine film are eluted by acid to obtain a working electrode having a porous poly-o-phenylenediamine film deposited on its surface.

[0009] Furthermore, the electrolyte contains terpyridine ruthenium (Ru(bpy)3 2+ ) in PBS solution.

[0010] The present invention adopts o-phenylenediamine and Cs + Combined with the electrochemical deposition method, poly(o-phenylenediamine) was prepared on the electrode surface. The combined Cs + Acid elution can be used to construct an ECL detection device with a porous structure to detect Cs in complex environments. + There is obvious selective binding. + It can selectively bind to the lone pair electrons of nitrogen atoms in poly(o-phenylenediamine) to enhance the resistance of the detection device. 2+ The ECL signal in PBS solution decreased significantly, and the LOD value could reach 50pg / L.

[0011] Furthermore, the solvent is phosphate buffer.

[0012] Furthermore, the acid is hydrochloric acid.

[0013] Furthermore, the molar ratio of o-phenylenediamine to cesium salt is 1:(20-50).

[0014] Furthermore, the electrochemical deposition method adopts a three-electrode system, including a working electrode, a counter electrode, a reference electrode and an electrolyte, and the electrode with the poly-o-phenylenediamine film deposited on the surface is used as the working electrode.

[0015] Furthermore, the working parameters of the electrochemical deposition method are: scanning voltage of 0.2-0.8V, scanning of 20-30 circles, and scanning speed of 50-60mV / s.

[0016] Furthermore, the electrolyte is a PBS solution.

[0017] Furthermore, the detection limit of the cesium ion is 50pg / L.

[0018] A second aspect of the present invention provides a method for detecting trace cesium ions, using the ECL detector for detecting trace cesium ions provided in the first aspect, comprising the following steps:

[0019] (1) using the ECL detector to test the ECL signal intensity of the cesium ion standard solution, and establishing a correlation diagram between the cesium ion concentration and the ECL signal intensity according to the test results;

[0020] (2) The ECL detector is used to detect the ECL signal intensity of the test liquid, and the cesium ion concentration in the test liquid is determined according to the corresponding relationship of the ECL signal intensity in the mutual relationship diagram.

[0021] The third aspect of the present invention provides a working electrode for detecting trace cesium ions. A porous poly-o-phenylenediamine film is deposited on the surface of the working electrode, and the working electrode is prepared by the following method: o-phenylenediamine and a cesium salt are dissolved in a solvent to obtain a mixed solution; the mixed solution is used as an electrolyte, and the poly-o-phenylenediamine film is deposited on the electrode surface by an electrochemical deposition method; and the cesium ions in the poly-o-phenylenediamine film are eluted by acid to obtain a working electrode with a porous poly-o-phenylenediamine film deposited on the surface.

[0022] Furthermore, the molar ratio of o-phenylenediamine to cesium salt is 1:(20-50).

[0023] Furthermore, the electrochemical deposition method adopts a three-electrode system, including a working electrode, a counter electrode, a reference electrode and an electrolyte, and the electrode with the poly-o-phenylenediamine film deposited on the surface is used as the working electrode.

[0024] Furthermore, the working parameters of the electrochemical deposition method are: scanning voltage of 0.2-0.8V, scanning of 20-30 circles, and scanning speed of 50-60mV / s.

[0025] The fourth aspect of the present invention provides an electrochemiluminescence detection instrument based on screen-printed electrodes, including an electrochemiluminescence system, a luminescence receiving system and a photoelectric conversion system. The electrochemiluminescence system is used for electrical signal control, including an electrochemical workstation and an electrode system. The electrode system includes a screen-printed electrode, and the screen-printed electrode includes a substrate and a working electrode, a reference electrode, and a counter electrode provided by the third aspect printed on the substrate; the photoelectric conversion system is used for photoelectric signal output, including a photomultiplier tube.

[0026] Electrochemiluminescence detection instruments based on screen-printed electrodes can be used to monitor trace amounts of cesium with ultra-sensitivity, high selectivity, accuracy, and rapidity, which is of great significance in the fields of environment and nuclear safety.

[0027] Beneficial effects of the present invention:

[0028] (1) The ECL detector for detecting trace cesium ions provided by the present invention has an ultra-low detection limit. According to the standard curve, the water sample detection result is 50pg / L, while the detection limit of ICP-MS is higher (usually greater than 10ng / L) and cannot be applied to high-salt samples. The technology of the present invention can achieve the detection of cesium ions (Cs + ), which is of great significance in the fields of environmental monitoring and food safety.

[0029] (2) The ECL detector for detecting trace cesium ions provided by the present invention has high selectivity. Cesium ions can specifically enter the imprinted pores and quench the electrochemical luminescence signal. The addition of common interfering ions, including alkali metal and alkaline earth metal ions and heavy metal ions, does not cause interference, indicating that the ECL detector has high selectivity in detecting specific target substances.

[0030] (3) The ECL detector for detecting trace cesium ions provided by the present invention has the advantages of on-site visual detection and the ability to analyze actual samples. It has been successfully applied to the visual determination of trace cesium ions in water samples and fish samples, demonstrating the ability of the ECL detector to perform rapid detection directly on-site. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 Schematic diagram of the principle of the ECL detector for detecting trace cesium ions in Example 2.

[0032] Figure 2 This is a schematic diagram of the structure of the electrochemiluminescence detection instrument based on screen-printed electrodes of Example 3.

[0033] Figure 3 Graphs showing the test results of the ECL detector in the presence of different concentrations of cesium ions; wherein A is a graph showing the ECL signal intensity data for testing cesium ion solutions of different concentrations, and B is a calibration curve graph showing the logarithm of the ECL signal intensity and the cesium ion concentration.

[0034] Figure 4 The graphs are test results of the selectivity and stability of the ECL detector and the non-imprinted ECL detector for cesium ions; wherein A is a graph of the ECL signal intensity data of the ECL detector, and B is a graph of the ECL signal intensity data of the non-imprinted ECL detector.

[0035] Figure 5 This is a visual detection diagram of the ECL detector performing ECL imaging on cesium ion solutions with different concentrations.

[0036] Figure 6The ECL detector is used to test various natural samples such as fresh water, salt water, organisms (fish, arthropods, mollusks), etc.; A is the ECL detection of freshwater biological samples, B is the imaging of seawater biological samples, and C is the actual sample detection result. DETAILED DESCRIPTION

[0037] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0038] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention.

[0039] Unless otherwise specified, the experimental methods used in the following examples are all conventional methods, and the materials, reagents, etc. used are all available from commercial sources unless otherwise specified.

[0040] Example 1

[0041] A working electrode for detecting trace cesium ions, wherein a porous poly-o-phenylenediamine film is deposited on the surface of the working electrode, and the working electrode is prepared by the following method:

[0042] (1) 216 mg of o-phenylenediamine (CAS: 95-54-5) was weighed and dissolved in 200 mL of 0.1 M pH = 6 phosphate buffer, and 80 μL of cesium chloride solution (0.04 mol) was added dropwise to obtain a mixed solution;

[0043] (2) Using the mixed solution obtained in step (1) as the electrolyte, the pretreated glassy carbon electrode as the working electrode, the platinum wire electrode as the counter electrode, and the silver-silver chloride electrode as the reference electrode, a poly(o-phenylenediamine) imprinted film is deposited by cyclic voltammetry, and the working parameters are: scanning voltage 0.2-0.8 V, scanning 20 circles, and scanning speed 50 mV / s; the pretreatment of the glassy carbon electrode is: polishing the glassy carbon electrode with α-alumina powder for three minutes, ultrasonically cleaning it with ethanol and water respectively, and blowing dry the water with argon gas to obtain the pretreated glassy carbon electrode.

[0044] (3) Using hydrochloric acid to elute the cesium ions in the poly(o-phenylenediamine) film, washing out the cesium ion-imprinted pores, and obtaining a working electrode having a poly(o-phenylenediamine) film with a porous structure deposited on the surface.

[0045] Example 2

[0046] An ECL detector for detecting trace cesium ions comprises the working electrode, reference electrode, counter electrode, electrolyte and photomultiplier tube of Example 1, with an Ag / AgCl electrode as the reference electrode, a platinum wire electrode as the counter electrode, and a PBS solution containing terpyridine ruthenium (wherein the concentration of terpyridine ruthenium is 1 mM and the concentration of PBS is 0.1 M) as the electrolyte.

[0047] Figure 1 Schematic diagram of the principle of the ECL detector for detecting trace cesium ions in Example 2.

[0048] Example 3

[0049] An electrochemical luminescence detection instrument based on screen-printed electrodes, comprising an electrochemical luminescence system, a luminescence receiving system and a photoelectric conversion system. The electrochemical luminescence system is used for electrical signal control, comprising an electrochemical workstation and an electrode system. The electrode system comprises a screen-printed electrode, and the screen-printed electrode comprises a substrate and a working electrode, a reference electrode and a counter electrode of Example 1 printed on the substrate; the photoelectric conversion system is used for photoelectric signal output, comprising a photomultiplier tube, such as Figure 2 shown.

[0050] Test Example 1

[0051] The ECL detector for detecting trace cesium ions of Example 2 was used to test cesium ion solutions of different concentrations. The test method was as follows: cesium ion solutions of different concentrations were dripped onto the working electrode of the ECL detector. After sufficient incubation for 30 minutes, the electrode was rinsed for electrochemiluminescence detection. 1 mL of 10 mM terpyridine ruthenium solution was diluted to 10 mL using 0.1 mol / L PBS solution with pH = 7.4 in the measuring cell to obtain 1 mM terpyridine ruthenium solution. A cyclic potential of 0 V to +2.0 V was applied to the ECL detector, and the ECL signal was detected at a scanning rate of 100 mV / s. The voltage at which the ECL intensity of the bare electrode reached 3.0 au was measured as the PMT value test condition.

[0052] Test results such as Figure 3 As shown in the figure, as the cesium ion concentration increases, the ECL signal gradually weakens. The ECL signal intensity of the ECL detector has a good linear relationship. When the cesium ion concentration is 100pg / L to 100μg / L, the ultra-low LOD value of the ECL detector is 50pg / L.

[0053] Test Example 2

[0054] The selectivity and stability of the ECL detector and the non-imprinted ECL detector for detecting trace cesium ions in Example 2 were tested by performing tests on a blank group, an interfering ion group, a high salt group, and an interfering ion group with cesium ions added (100 ng / L). The interfering ions were K in the environmental water sample. + 、Na + Mg 2+ , Ca 2+ , Sr 2+ And the representative of heavy metals Pb 2+ , Cu 2+ 、Zn 2+ , Fe 3+ , Mn 2+ 、Co 2+ and Ni 2+ (Each ion concentration is 250 mg / L); the ion in the high salt group is K + 、Na + Mg 2+ , Ca 2+ (Concentration of each ion is 1g / L).

[0055] Test results such as Figure 4 As shown, Figure 4 The comparison of the four sets of data of the ECL detector in Figure A shows that despite the addition of interfering ions, the ECL detector still has good selectivity for cesium ions. Figure 4 Four sets of data comparison of the non-imprinted ECL detector in Figure B. The device detects interfering ions and Cs + No obvious response was produced at any concentration, which proved the reliability of the ECL detector of the present invention.

[0056] Test Example 3

[0057] The ECL detector for detecting trace cesium ions of Example 2 was used to further perform ECL imaging, with cyclic voltage scanning from 0 V to 2.0 V, and visualization using a charge coupled device (CCD) to achieve rapid determination of trace cesium ions.

[0058] Test results such as Figure 5 As shown in the figure, after the ECL detector is treated with a high concentration of cesium ion solution, the ECL signal is quenched. Visualization can truly reflect the intensity of the ECL signal. Compared with the control sample, ECL imaging has an indispensable advantage in accurately and quickly judging whether the sample under test exceeds the standard.

[0059] Test Example 4

[0060] In order to further confirm the practicality of the ECL detector, the ECL detector for detecting trace cesium ions of Example 2 was further applied to the detection of various natural samples such as fresh water, salt water, organisms (fish, arthropods, mollusks), etc.

[0061] Test results such as Figure 6 As shown in the figure, the results show that the device has a wide range of applications in environmental testing, including biological samples, fresh water and even high-salinity samples. + The concentration is significantly higher than that of fresh water. + The concentration is also significantly higher than that in spring water. This phenomenon may be caused by the enrichment process from spring water to lakes and rivers, and then to salt lakes and oceans. Similarly, the cesium content in marine animal samples is also significantly higher than that in freshwater animal samples. The ECL detector shows excellent sensitivity and selectivity in detecting trace cesium ions, especially when dealing with complex biological and water samples, and can effectively distinguish cesium concentrations under different salinities and ecological environments. This makes the detector have great application potential in environmental monitoring, food safety and ecological research. Its fast and accurate detection capabilities provide strong technical support for environmental protection and resource management, and help to gain a deeper understanding of the migration and enrichment mechanism of cesium in different ecosystems.

[0062] The samples of Dashipa, Qinling mountain spring water and Yellow Sea water were spiked and tested: 1 mL of Dashipa was taken, and 10 μL of 1 μg / L CsCl standard solution was added, which was converted into a mass concentration of 0.5 ng / g; 1 mL of Qinling mountain spring water was taken, and 10 L of 1 μg / LCsCl standard solution was added, which was 10 ng / L; 1 mL of Yellow Sea water was taken, and 10 μL of 1 mg / L CsCl standard solution was added, which was 10 μg / L. The spiked cesium ions were detected using the same method as the actual samples, and the test results are shown in Table 1:

[0063] Table 1

[0064]

[0065]

[0066] It can be seen from Table 1 that the error of the spiked recovery rate of the actual samples does not exceed 5%, indicating that the experimental results have high accuracy.

[0067] Obviously, the above embodiments of the present invention are only examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Those skilled in the art should understand that other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. An ECL detector for detecting trace cesium ions, comprising a working electrode, a reference electrode, a counter electrode, an electrolyte and a photomultiplier tube, characterized in that: A poly(o-phenylenediamine) film with a porous structure is deposited on the surface of the working electrode.

2. The ECL detector for detecting trace cesium ions according to claim 1, characterized in that: The working electrode with a porous poly-o-phenylenediamine film deposited on the surface is prepared by the following method: o-phenylenediamine and cesium salt are dissolved in a solvent to obtain a mixed solution; the mixed solution is used as an electrolyte to deposit the poly-o-phenylenediamine film on the electrode surface by an electrochemical deposition method; and cesium ions in the poly-o-phenylenediamine film are eluted by acid to obtain the working electrode with a porous poly-o-phenylenediamine film deposited on the surface.

3. The ECL detector for detecting trace cesium ions according to claim 2, characterized in that: The molar ratio of the o-phenylenediamine to the cesium salt is 1:(20-50).

4. The ECL detector for detecting trace cesium ions according to claim 2, characterized in that: The solvent is phosphate buffer.

5. The ECL detector for detecting trace cesium ions according to claim 2, characterized in that: The electrochemical deposition method adopts a three-electrode system, including a working electrode, a counter electrode, a reference electrode and an electrolyte, and uses the electrode with the poly-o-phenylenediamine film deposited on the surface as the working electrode.

6. The ECL detector for detecting trace cesium ions according to claim 2, characterized in that: The working parameters of the electrochemical deposition method are: scanning voltage of 0.2-0.8V, scanning of 20-30 circles, and scanning speed of 50-60mV / s.

7. The ECL detector for detecting trace cesium ions according to claim 1, characterized in that: The detection limit of the cesium ion is 50 pg / L.

8. A method for detecting trace cesium ions, characterized in that: The ECL detector for detecting trace cesium ions according to any one of claims 1 to 7 comprises the following steps: (1) using the ECL detector to test the ECL signal intensity of the cesium ion standard solution, and establishing a correlation diagram between the cesium ion concentration and the ECL signal intensity according to the test results; (2) The ECL detector is used to detect the ECL signal intensity of the test liquid, and the cesium ion concentration in the test liquid is determined according to the corresponding relationship of the ECL signal intensity in the mutual relationship diagram.

9. A working electrode for detecting trace cesium ions, characterized in that: A poly-o-phenylenediamine film with a porous structure is deposited on the surface of the working electrode, and is prepared by the following method: o-phenylenediamine and cesium salt are dissolved in a solvent to obtain a mixed solution; the mixed solution is used as an electrolyte to deposit the poly-o-phenylenediamine film on the electrode surface by an electrochemical deposition method; and cesium ions in the poly-o-phenylenediamine film are eluted by acid to obtain a working electrode with a poly-o-phenylenediamine film with a porous structure deposited on the surface.

10. An electrochemiluminescence detection instrument based on screen-printed electrodes, characterized in that: It includes an electrochemical luminescence system, a luminescence receiving system and a photoelectric conversion system. The electrochemical luminescence system is used for electrical signal control, and includes an electrochemical workstation and an electrode system. The electrode system includes a screen-printed electrode, and the screen-printed electrode includes a substrate and the working electrode, reference electrode and counter electrode as described in claim 9 printed on the substrate; the photoelectric conversion system is used for photoelectric signal output, and includes a photomultiplier tube.

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