A pH type electrochemiluminescence sensor based on copper indium sulfide / carbazide system and a preparation method thereof

Abstract

The application relates to a pH type electrochemiluminescence sensor based on a copper indium sulfide / carbazide system and a preparation method. The method comprises the following steps: firstly, synthesizing core-shell structure copper indium sulfide nanocrystals through a one-pot method; and secondly, taking the purified copper indium sulfide nanocrystals as a luminescent substance to prepare the pH type electrochemiluminescence sensor based on the copper indium sulfide / carbazide system. Under different pH value conditions, the sensor shows obvious pH-dependent electrochemiluminescence, and the electrochemiluminescence spectra of different pH values are all in the near infrared region and are induced by surface defects. The maximum wavelength of the electrochemiluminescence is 743 nm in the near infrared region. The sensor shows obvious anodic or cathodic electrochemiluminescence signals under different pH value conditions, presents corresponding linear correlations, and can quantitatively detect the pH value of a solution.

Description

TECHNICAL FIELD

[0001] The application relates to a pH type electrochemiluminescence sensor based on a copper indium sulfide / carbazide system and a preparation method, and belongs to the field of analytical technology methods. BACKGROUND

[0002] The pH value is one of the most important physicochemical parameters of an aqueous solution, and is related to natural phenomena, chemical changes and production processes involving aqueous solutions.

[0003] In a biological system, the pH value plays an important role in some physiological processes, such as cell proliferation, enzyme activity, ion transport and cancer cell survival state (J. Am. Chem. Soc., 2009, 131, 3016; Chem. Rev., 2010, 5, 2709.). Therefore, the determination of the pH value has always been an indispensable work in the fields of industrial and agricultural production, scientific research, clinical medicine, environmental protection and monitoring.

[0004] The pH glass electrode is the most representative chemical sensor for determining the hydrogen ion activity, but it has defects such as high impedance, difficulty in miniaturization, easy breakage, inability to be used for pH measurement of HF-containing solutions, existence of'sodium error' and 'acid error', which limit its application in intracellular pH detection and cell imaging research. Electrochemiluminescence sensors are favored by a large number of scientific researchers due to their high sensitivity, good selectivity, low detection limit and simple instrument operation. SUMMARY

[0005] In view of the deficiencies of the prior art, the application provides a pH type electrochemiluminescence sensor based on a copper indium sulfide / carbazide system and a preparation method.

[0006] The pH type electrochemiluminescence sensor based on the copper indium sulfide / carbazide system provided by the application has a maximum wavelength of near-infrared 743 nm under the condition of the carbazide co-reactant. The sensor shows obvious anodic or cathodic electrochemiluminescence signals under different pH conditions, presents corresponding linear correlations, and can quantitatively detect the pH value of a solution.

[0007] The application is realized by the following technical scheme:

[0008] The preparation method of the pH type electrochemiluminescence sensor based on the copper indium sulfide / carbazide system comprises the following steps:

[0009] (1) mixing copper chloride solution, indium chloride solution, glutathione solid powder and sodium citrate solution into ultrapure water, stirring uniformly to obtain a mixed solution a; injecting a sodium sulfide solution, changing the solution from colorless to deep yellow, heating the obtained solution to obtain a core structure copper indium sulfide nanocrystal solution;

[0010] (2) mixing thiourea, glutathione and zinc acetate solution into ultrapure water to obtain a mixed solution b, and injecting the mixed solution b into the core-structure copper indium sulfide nanocrystal solution obtained in step (1) to perform a heating reaction;

[0011] (3) purifying the obtained precipitate after the heating reaction with isopropyl alcohol, and obtaining a core-shell structure copper indium sulfide nanocrystal;

[0012] (4) taking the core-shell structure copper indium sulfide nanocrystal as a light-emitting substance, and placing the indium sulfide core-shell structure nanocrystal on a glassy carbon electrode to dry at room temperature to obtain a pH type electrochemiluminescence sensor.

[0013] According to the present application, preferably, in step (1), the concentration of the copper chloride solution is 0.005-0.02 M, the concentration of the indium chloride solution is 4.0-6.0 mM, the concentration of the sodium citrate solution is 0.2-0.6 M, and the concentration of the sodium sulfide solution is 0.5-2 M.

[0014] According to the present application, preferably, in step (1), the molar ratio of the mixture of copper chloride, indium chloride, glutathione and sodium sulfide is (40-50):1:(700-900):(270-470).

[0015] Further preferably, the molar ratio of the mixture of copper chloride, indium chloride, glutathione and sodium sulfide is 45:1:800:370.

[0016] According to the present application, preferably, in step (1), the molar ratio of indium chloride to sodium citrate is 1:(0.6-20).

[0017] According to the present application, preferably, in step (1), the volume ratio of the copper chloride solution to ultrapure water is (0.5-2):(10-30).

[0018] According to the present application, preferably, in step (1), the heating reaction is performed at 90-100℃ for 30-60 minutes.

[0019] According to the present application, preferably, in step (2), the molar ratio of thiourea, zinc acetate and glutathione is (5-15):(8-12):(8-25).

[0020] According to the present application, preferably, in step (2), the molar ratio of thiourea, zinc acetate and glutathione is 12:10:15.

[0021] According to the present application, preferably, in step (2), the mass-to-volume ratio of thiourea to ultrapure water is (0.01-0.1):(10-30), unit, g / mL.

[0022] According to the application, preferably, in step (2), the volume ratio of the mixed solution b to the copper indium sulfide nanocrystal solution with core structure is 1:(3-6).

[0023] According to the application, preferably, in step (2), the heating reaction is heating at 90-100℃ for 20-40 minutes.

[0024] According to the application, preferably, in step (3), the isopropyl alcohol purification is adding isopropyl alcohol to the solution of step (2) and centrifuging at 13300 r / min.

[0025] According to the application, preferably, in step (4), the concentration of the copper indium sulfide nanocrystal with core-shell structure is 0.5-3 mg / mL.

[0026] According to the application, preferably, in step (4), the amount of the copper indium sulfide nanocrystal with core-shell structure is 9-11 μL.

[0027] The aqueous solution of the copper indium sulfide nanocrystal with core-shell structure obtained in step (3) is wine red, the maximum fluorescence emission wavelength of copper indium sulfide under the optimal conditions is 645 nm in near-infrared, the fluorescence under ultraviolet light is obvious red, and the maximum wavelength of electrochemiluminescence under the condition of carbazide as a co-reactant is 743 nm in near-infrared.

[0028] One preferred embodiment of the application

[0029] A preparation method of a pH type electrochemiluminescence sensor based on a copper indium sulfide / carbazide system, comprising the following steps:

[0030] (1) 900 μL of a copper chloride solution with a concentration of 0.005-0.02 M, 40 μL of an indium chloride solution with a concentration of 4.0-6.0 mM, 0.0062 g of a solid glutathione powder and 400 μL of a sodium citrate solution with a concentration of 0.2-0.6 M are mixed into 20 mL of ultrapure water, stirred uniformly to obtain a mixed solution a; 62 μL of a sodium sulfide solution with a concentration of 0.5-2 M is injected, the solution changes from colorless to deep yellow, and the obtained solution is heated at 95℃ for 40 minutes to obtain a copper indium sulfide nanocrystal core structure;

[0031] (2) 0.061 g of thiourea, 0.376 g of glutathione and 0.177 g of a zinc acetate solution are mixed into 20 mL of ultrapure water to obtain a mixed solution b; 5 mL of the mixed solution b is injected into the solution obtained in step (1) and heated at 95℃ for another 30 minutes;

[0032] (3) the copper indium sulfide nanocrystal obtained in step (2) is centrifuged and purified with isopropyl alcohol, and the obtained precipitate is a copper indium sulfide nanocrystal with core-shell structure;

[0033] (4) Take 9-11 μL of 0.5-3 mg / mL of the core-shell structure copper indium sulfide nanocrystal of step (3) and drop on the glassy carbon electrode to dry at room temperature to prepare a pH type electrochemiluminescence sensor based on the copper indium sulfide / carbazide system.

[0034] A pH type electrochemiluminescence sensor based on the copper indium sulfide / carbazide system is prepared by the above method.

[0035] The anodic or cathodic electrochemiluminescence signal of the pH type electrochemiluminescence sensor based on the copper indium sulfide / carbazide system is measured under different pH conditions with carbazide as a co-reactant. The anodic electrochemiluminescence signal of the electrochemiluminescence sensor increases with the increase of pH value, and shows a linear correlation in the range of pH 5-12, with R 2 = 0.996; the cathodic electrochemiluminescence signal of the electrochemiluminescence sensor increases with the decrease of pH value, and shows a linear correlation in the range of pH 1-4, with R 2 = 0.992.

[0036] The pH type electrochemiluminescence sensor exhibits obvious anodic or cathodic electrochemiluminescence signal under different pH conditions, and shows a corresponding linear correlation, so that the pH value of the solution can be quantitatively detected.

[0037] The application of the pH type electrochemiluminescence sensor based on the copper indinium sulfide / carbazide system is for quantitatively detecting the pH value of the solution.

[0038] According to the application, the method for quantitatively detecting the pH value of the solution by the pH type electrochemiluminescence sensor based on the copper indinium sulfide / carbazide system comprises the following steps:

[0039] 1) The pH type electrochemiluminescence sensor based on the copper indinium sulfide / carbazide system is used as a working electrode, and carbazide is used as a co-reactant, and the cathodic or anodic electrochemiluminescence signal of the system is measured in electrolyte solutions with different known pH values, and a working curve is drawn according to the pH value corresponding to the electrochemiluminescence signal;

[0040] 2) The pH type electrochemiluminescence sensor based on the copper indinium sulfide / carbazide system is used as a working electrode, and carbazide is used as a co-reactant, and the cathodic or anodic electrochemiluminescence signal of the system is measured in a solution to be detected, and the pH value of the solution to be detected is obtained according to the working curve.

[0041] According to the application, the electrolyte solution is a hydrochloric acid-tris buffer solution, a phosphate buffer solution or a carbonate buffer solution.

[0042] According to the application, the concentration of carbazide in the system is 10-60 mM.

[0043] Technical features and advantages of the present application:

[0044] 1、The present application prepares core-shell structure copper indium sulfide nanocrystals by one-pot method, and the prepared copper indium sulfide nanocrystals have the advantages of not containing toxic elements, good biological affinity and storage stability.

[0045] 2、The pH type electrochemiluminescence sensor based on the copper indium sulfide / carbazide system of the present application has a maximum wavelength of near-infrared electrochemiluminescence of 743 nm under the condition of the carbazide co-reactant. The sensor shows obvious anodic or cathodic electrochemiluminescence signals under different pH conditions, the anodic electrochemiluminescence signal increases with the increase of the pH value, and shows linear correlation in the range of electrolyte pH 5-12, the cathodic electrochemiluminescence signal decreases with the increase of the pH value, and shows linear correlation in the range of electrolyte pH 1-4, so that the pH value of the solution can be quantitatively detected, and the sensor has high accuracy, good reproducibility, strong stability, high sensitivity, more convenient and flexible operation, and low detection cost.

[0046] 3、The electrochemiluminescence radiation of the present application can detect electrolytes with pH value in the range of 1-12 in the anodic and cathodic ranges respectively, and has strong linear correlation. BRIEF DESCRIPTION OF DRAWINGS

[0047] Fig. 1 The normalized cathodic electrochemiluminescence spectrum diagram of the pH type electrochemiluminescence sensor prepared for Example 1 under the condition of pH 1-4.

[0048] Fig. 2 The cathodic electrochemiluminescence light intensity spectrum diagram of the pH type electrochemiluminescence sensor prepared for Example 1 under the condition of pH 1-4.

[0049] Fig. 3 The cathodic electrochemiluminescence light intensity working curve of the pH type electrochemiluminescence sensor prepared for Example 1 under the condition of pH 1-4.

[0050] Fig. 4 The normalized anodic electrochemiluminescence spectrum diagram of the pH type electrochemiluminescence sensor prepared for Example 1 under the condition of pH 5-12.

[0051] Fig. 5 The anodic electrochemiluminescence light intensity spectrum diagram of the pH type electrochemiluminescence sensor prepared for Example 1 under the condition of pH 5-12.

[0052] Fig. 6 The anodic electrochemiluminescence light intensity working curve of the pH type electrochemiluminescence sensor prepared for Example 1 under the condition of pH 5-12.

[0053] Fig. 7The pH-type electrochemiluminescence sensor prepared in Example 1 was used to draw the working curve of the electrochemiluminescence intensity under different pH conditions, with tripropylamine as a co-reactant. DETAILED DESCRIPTION

[0054] The application is further illustrated by the following examples without being limited thereto.

[0055] The fluorescence spectrum of the copper indium sulfide nanocrystals described in the examples was obtained by collecting the spectrum with an F-4700 fluorescence spectrophotometer,

[0056] The ultraviolet-visible light absorption spectrum was obtained by collecting the spectrum with an A Agilent cary 60 ultraviolet-visible spectrophotometer,

[0057] The electrochemiluminescence spectrum was obtained by collecting the spectrum with a GCFG-A electrochemiluminescence spectrum collection system developed by Shandong Guochen Biological Technology Co., Ltd. The potential window used was 0-1.6 volts, and the scanning speed was 50 millivolts per second.

[0058] The electrochemiluminescence test used a glassy carbon electrode as the working electrode, an Ag / AgCl electrode as the reference electrode, and a Pt wire as the counter electrode. A copper indium sulfide modified electrode was prepared by dropping 10 μL of a 2 milligram / milliliter copper indium sulfide solution on the surface of the working electrode and allowing it to dry. The test solution was a 0.1 molar / liter phosphate buffer solution (pH 7.4) containing 50 millimoles / liter carbazide. The collected electrochemiluminescence spectrum was the integrated spectrum of all electrochemiluminescence radiation.

[0059] Example 1

[0060] The preparation method of the pH-type electrochemiluminescence sensor based on the copper indium sulfide / carbazide system is as follows:

[0061] (1) 900 μL of copper chloride solution (0.01 M), 40 μL of indium chloride solution (5.0 mM), 0.0062 g of glutathione solid powder, and 400 μL of sodium citrate solution (0.4 M) were mixed into 20 milliliters of ultrapure water, stirred uniformly in a 100 milliliter three-necked flask, 62 μL of sodium sulfide solution (1.0 M) was injected, the solution changed from colorless to deep yellow, and the resulting solution was heated at 95°C for 40 minutes to obtain a core structure copper indium sulfide nanocrystal solution;

[0062] (2) 0.061 g of thiourea, 0.376 g of glutathione, and 0.177 g of zinc acetate solution were mixed into 20 milliliters of ultrapure water to obtain a mixed solution, 5 milliliters of the mixed solution were injected into the core structure copper indium sulfide nanocrystal solution obtained in step (1), and the mixture was further heated at 95°C for 30 minutes; then the obtained precipitate was purified by centrifugation with isopropanol.

[0063] (4) The pH-type electrochemiluminescence sensor was prepared by dropping 10 μL of 2 mg / mL core-shell copper indium sulfide nanocrystal solution on the glassy carbon electrode and drying at room temperature.

[0064] Example 2

[0065] The method for quantitatively detecting the pH value of a solution by using the pH-type electrochemiluminescence sensor based on the copper indium sulfide / carbazide system is as follows:

[0066] 1) The working electrode of the pH-type electrochemiluminescence sensor based on the copper indium sulfide / carbazide system in Example 1 was used, and the cathode or anode electrochemiluminescence signal of the system was measured in an electrolyte solution with a known pH value, and a working curve was plotted according to the pH value corresponding to the electrochemiluminescence signal.

[0067] 2) The working electrode of the pH-type electrochemiluminescence sensor based on the copper indium sulfide / carbazide system in Example 1 was used, and the cathode or anode electrochemiluminescence signal of the system was measured in a solution to be detected, and the pH value of the detection solution was obtained according to the working curve.

[0068] The pH-type electrochemiluminescence sensor based on the copper indium sulfide / carbazide system in Example 1 exhibited obvious anode or cathode electrochemiluminescence signals under different pH conditions, and showed a corresponding linear correlation, so that the pH value of a solution could be quantitatively detected.

[0069] Experimental Example 1

[0070] The pH-type electrochemiluminescence sensor in Example 1 was used as the working electrode, an Ag / AgCl electrode was used as the reference electrode, a Pt wire was used as the counter electrode, the potential window used was 0-1.6 volts, the scanning speed was 50 millivolts per second, and the test solution was a 0.1M phosphate buffer solution containing 10mM carbazide; the electrochemiluminescence spectrum collected under different pH conditions was the integral spectrum of all ECL radiation.

[0071] The normalized cathode electrochemiluminescence spectrum, the cathode electrochemiluminescence light intensity spectrum, and the cathode electrochemiluminescence light intensity working curve of the pH-type electrochemiluminescence sensor prepared in Example 1 under the condition of pH 1-4 are shown in Figs. 1-3 .

[0072] Figs. 1-3 It can be seen that the pH-type electrochemiluminescence sensor based on the copper indium sulfide / carbazide system in Example 1 exhibited obvious cathode electrochemiluminescence signals under different pH conditions, and the maximum wavelength of the electrochemiluminescence was 743 nm in the near-infrared range under the condition of using carbazide as the co-reactant, and showed a linear correlation in the pH=1-4 range of the electrolyte solution, with an R 2 value of 0.992.

[0073] The normalized anodic electrochemiluminescence spectrum, anodic electrochemiluminescence intensity spectrum, and anodic electrochemiluminescence intensity working curve of the pH-type electrochemiluminescence sensor prepared in Example 1 under pH 5-12 conditions are shown in the figure below. Figs. 4-6 .

[0074] Figs. 4-6 It can be seen that a significant anodic electrochemiluminescence signal is exhibited under different pH conditions. With carbazine as a co-reactant, the maximum wavelength of electrochemiluminescence is 743 nm in the near-infrared range, showing a linear correlation within the electrolyte pH range of 5-12. R 2 The value is 0.996.

[0075] Comparative Example 1

[0076] Using the pH-type electrochemiluminescence sensor from Example 1 as the working electrode, an Ag / AgCl electrode as the reference electrode, and a Pt wire as the counter electrode, the potential window used was 0–1.6 V, the scan rate was 50 mV / s, and tripropylamine was used as the conventional co-reactant to replace carbazine in Example 1. The electrochemiluminescence intensity under different pH conditions is shown in [Figure 1]. Fig. 7 ,pass Fig. 7 It can be seen that the electrochemiluminescence intensity values ​​under different pH conditions are not linearly correlated, making it impossible to detect pH.

[0077] Example 3

[0078] The preparation method is the same as that described in Example 1, except that:

[0079] In step (1), the concentration of copper chloride solution was 0.008M, the concentration of indium chloride solution was 4.5mM, the concentration of sodium citrate solution was 0.3M, the concentration of sodium sulfide solution was 0.8M, and the rest was carried out as in Example 1.

[0080] Example 4

[0081] The preparation method is the same as that described in Example 1, except that:

[0082] In step (2), 0.058 g thiourea, 0.366 g glutathione and 0.180 g zinc acetate solution were mixed into 20 mL of ultrapure water to obtain a mixture. 5 mL of the mixture was injected into the core-shell copper indium sulfide nanocrystal solution obtained in step (1), and the mixture was heated at 95 °C for 30 minutes. Then, the mixture was purified by centrifugation with isopropanol. The resulting precipitate was the core-shell copper indium sulfide nanocrystal. Other steps were performed according to Example 1.

Claims

1. A method for quantitatively detecting the pH value of a solution based on a copper indium sulfide / carbazide system pH-type electrochemiluminescence sensor, comprising the following steps: 1) Using a copper indium sulfide / carbazide system pH-type electrochemiluminescence sensor as a working electrode and carbazide as a co-reactant, the cathode or anode electrochemiluminescence signal of the system in a known different pH value electrolyte solution is determined, and a working curve is drawn according to the pH value corresponding to the electrochemiluminescence signal; 2) Using a copper indium sulfide / carbazide system pH-type electrochemiluminescence sensor as a working electrode and carbazide as a co-reactant, the cathode or anode electrochemiluminescence signal of the system in a solution to be detected is determined, and the pH value of the solution to be detected is obtained according to the working curve, The electrolyte solution is a hydrochloric acid-tris buffer solution, a phosphate buffer solution or a carbonate buffer solution, and the concentration of carbazide in the system is 10-60 mM; The copper indium sulfide / carbazide system pH-type electrochemiluminescence sensor is constructed according to the following method: (1) mixed copper chloride solution, indium chloride solution, glutathione solid powder and sodium citrate solution into ultrapure water, stirred uniformly to obtain a mixed solution a; Sodium sulfide solution is injected, the solution changes from colorless to deep yellow, and the obtained solution is heated to obtain a core structure copper indium sulfide nanocrystal solution; (2) Thiourea, glutathione and zinc acetate solution are mixed into ultrapure water to obtain a mixed solution b, the mixed solution b is injected into the core structure copper indium sulfide nanocrystal solution obtained in step (1) and heated to react; (3) After heating, isopropanol is used for purification, and the obtained precipitate is a core-shell structure copper indium sulfide nanocrystal; (4) The core-shell structure copper indium sulfide nanocrystal obtained by purification in step (3) is used as a luminescent material, the core-shell structure copper indium sulfide nanocrystal is placed on a glassy carbon electrode and dried at room temperature to prepare a pH-type electrochemiluminescence sensor.

2. The method of claim 1, wherein, In step (1), the concentration of copper chloride solution is 0.005-0.02 M, the concentration of indium chloride solution is 4.0-6.0 mM, the concentration of sodium citrate solution is 0.2-0.6 M, and the concentration of sodium sulfide solution is 0.5-2 M.

3. The method of claim 1, wherein, In step (1), the molar ratio of copper chloride: indium chloride: glutathione: sodium sulfide mixed is = (40-50): 1: (700-900): (270-470).

4. The method of claim 1, wherein, In step (1), the molar ratio of indium chloride to sodium citrate is 1: (0.6-20), and the volume ratio of copper chloride solution to ultrapure water is (0.5-2): (10-30), and the heating reaction is heating at 90-100°C for 30-60 minutes.

5. The method of claim 1, wherein, In step (2), the molar ratio of thiourea: zinc acetate: glutathione is (5-15): (8-12): (8-25).

6. The method of claim 1, wherein, In step (2), the mass-volume ratio of thiourea in ultrapure water is (0.01-0.1): (10-30), unit, g / mL, the volume ratio of mixed solution b to core structure copper indium sulfide nanocrystal solution is 1: (3-6), and the heating reaction is heating at 90-100°C for 20-40 minutes.

7. The method of claim 1, wherein, In step (3), isopropanol purification is adding isopropanol to the solution of step (2) and centrifuging at 13300 r / min, and in step (4), the concentration of core-shell structure copper indium sulfide nanocrystal is 0.5-3 mg / mL, and in step (4), the amount of core-shell structure copper indium sulfide nanocrystal is 9-11 μL.

Images