CN112986220A

CN112986220A - For Hg2+Method for preparing electrochemiluminescence sensor for detection

Info

Publication number: CN112986220A
Application number: CN202110176092.9A
Authority: CN
Inventors: 田春媛; 华情; 庄旭明; 栾锋; 岳喜典; 赵瑞; 李敏
Original assignee: Yantai University
Current assignee: Yantai University
Priority date: 2021-02-06
Filing date: 2021-02-06
Publication date: 2021-06-18
Anticipated expiration: 2041-02-06
Also published as: CN112986220B

Abstract

The invention provides a mercury-free mercury solution²⁺A method for preparing a detected electrochemiluminescence sensor; the method comprises the following steps: step 1, preparation of europium sulfide nanocrystals: step 2, preparing a sensor: step 3, preparation of detection products: adding part of ultrapure water into marine products, crushing, centrifuging at 9000r/min for 6min, filtering to obtain supernatant, and standing; and 4, carrying out detection analysis. The novel sensor prepared by the invention has excellent electrocatalytic activity to EuS NCs, and has the remarkable advantages of low detection limit, high sensitivity, good anti-interference performance and the like. The EuS NCs electrochemical sensor constructed based on the invention has the advantages of simple preparation, low cost and environmental friendlinessAnd has wide application prospect in the protection aspect of the ecological system.

Description

For Hg2+Method for preparing electrochemiluminescence sensor for detection

Technical Field

The invention relates to the technical field of electrochemical luminescence detection; in particular to a mercury-free mercury vapor²⁺A preparation method of a detection electrochemiluminescence sensor.

Background

Mercury is one of the most well-known heavy metals in environmental pollutants and is also one of the most toxic elements affecting human and ecosystem health. It is usually present in and circulates in soil and groundwater, causing environmental pollution in animals and plants through various natural and man-made sources. If mercury is introduced into the human body in excess, it can cause damage to the kidneys, nerves, immune system and cardiovascular system. For example, the main source of neurotoxic mercury compounds is fish, which accumulate methylmercury in the body. Methylmercury from fish may cause nerve damage (water ensures disease) and heart attack.

At present to Hg²⁺There are many detection methods such as Atomic Absorption Spectrometry (AAS), ultraviolet spectrophotometry, fluorescence spectrometry, Atomic Fluorescence Spectrometry (AFS), inductively coupled plasma spectrometry (ICP-MS), electrochemical methods, and the like. Although these detection techniques may be used to analyze and detect Hg²⁺However, most require expensive instruments or cumbersome sample preparation to achieve the target Hg²⁺Detection of (3). In practical application, the method also has some limitations, such as poor selectivity and sensitivity, and is easily interfered by other metal ions. Therefore, a simple, rapid, high-sensitivity and high-selectivity method for detecting Hg is urgently needed²⁺The method of (1).

Disclosure of Invention

The invention aims to provide a mercury-free mercury vapor deposition²⁺A preparation method of a detection electrochemiluminescence sensor.

The invention is realized by the following technical scheme:

the invention relates to a method for Hg²⁺Electrochemiluminescence sensor for detectionThe preparation method comprises the following steps:

step 1, preparation of europium sulfide nanocrystals:

step 2, preparing a sensor:

step 3, preparation of detection products: adding part of ultrapure water into marine products, crushing, centrifuging at 9000r/min for 6min, filtering to obtain supernatant, and standing;

and 4, carrying out detection analysis.

Preferably, in step 1, the preparation of the europium sulfide nanocrystal specifically comprises:

0.1466g of EuCl₃·6H₂O, 10.0mL of 1-octadecene, 6mL of n-dodecyl mercaptan and 0.88mL of oleic acid-400 are mixed in a high-pressure reaction kettle, and the mixture is continuously stirred and vacuumized for 2 hours at 100 ℃; at 200 ℃ and N₂Reacting for 3 hours in the environment; when the solution is cooled to room temperature, using a mixture of methanol and acetone according to the volume ratio of 1:4 to precipitate and centrifuge for 3-5 times, wherein the rotating speed is 8000-10000r/min, and the time is 10min, and removing unreacted organic matters to obtain europium sulfide nano-crystals; dispersing the washed europium sulfide nano-crystal into CCl₄Putting the mixture into a refrigerator for storage for later use;

preferably, in step 2, the preparation of the sensor specifically comprises:

modifying europium sulfide nanocrystals onto a polished glassy carbon electrode, and drying in the shade at the position of the back to obtain a nanomaterial-modified electrode; the electrode modified by the nano material is a working electrode, the Ag/AgCl electrode is a reference electrode, and the platinum wire electrode is a counter electrode to form a three-electrode system; the three-electrode system is connected with an MPI-E type electrochemiluminescence analysis system to form a system for Hg²⁺A sensor for detecting.

Preferably, in step 4, the performing detection analysis specifically includes: taking 1mL of supernatant and 3mL of 50mM K₂S₂O₈Mixing with 0.1M PBS coreactant, detecting ECL in MPI-E type electrochemiluminescence analysis system by europium sulfide nanocrystalline, and verifying existence of Hg in marine products²⁺Are present.

Preferably, the 1-octadecene is a solvent; the eluent is a mixture of methanol and acetone according to a volume ratio of 1: 4.

Preferably, the seafood is marine fish, conch and mantis shrimp.

Preferably, the co-reactant has a pH of 7.4.

Preferably, in step 4, the working potential is-2.0-0V, the photomultiplier high voltage of the electrochemical workstation is 800V, and the scanning rate of the electrochemical workstation is 0.1V/S.

The invention has the following advantages:

(1) the europium sulfide nanocrystals (EuS NCs) as the material of the invention is a novel rare earth nanomaterial, and the material attracts people's attention due to unique excellent chemical properties, optical and magnetic characteristics, narrow emission peak and long fluorescence lifetime.

(2) The method is simple, low in cost, good in stability, good in biocompatibility and low in biotoxicity; at present, the method has been applied to the fields of biological analysis, environmental detection and the like. Compared with the existing detection methods, the material provided by the invention has the advantages of simple preparation process, mild reaction conditions, low cost and capability of rapid detection.

(3) The process to which the invention relates is focused on Hg in seafood²⁺Detection, providing a new method for environmental monitoring, particularly in fish, conch and shrimp, using ECL sensors based on the composite material to assess the presence of Hg in seafood²⁺。

(4) The Electrochemiluminescence (ECL) technology used in the invention has the advantages of simple operation, low cost, low detection limit, high selectivity and the like, and can be applied to biological analysis.

Drawings

FIG. 1 shows the preparation of EuS NCs composite material provided by the invention and the reaction with K₂S₂O₈Schematic diagram of the reaction;

FIG. 2 is a performance test chart of EuS NCs composites; wherein the left image (A) is a Transmission Electron Microscope (TEM) image of the EuS NCs composite material, and the right image (B) is a particle size analysis image of the EuS NCs composite material;

FIG. 3 is an energy spectrum analysis (EDS) of the EuS NCs composite material according to the present invention;

FIG. 4 is an X-ray diffraction pattern (XRD) of a EuS NCs composite material according to the present invention;

FIG. 5 is a Fourier transform infrared (FT-IR) spectrum of a EuS NCs composite according to the present invention;

FIG. 6 is a fluorescence spectrum of the EuS NCs composite according to the present invention;

FIG. 7 is an optimized graph of the EuS NCs composite material of the present invention for K2S2O8 at different pH values;

FIG. 8 shows ECL sensors constructed from EuS NCs composites of the present invention for different concentrations of Hg²⁺A linear graph of (a);

fig. 9 is respectively: (A) ECL stability of the EuS NCs composite, (B) ECL reproducibility plot of the EuS NCs composite;

FIG. 10 is a graph comparing the selectivity of EuS NCs composites of the present invention for other interfering ions.

Detailed Description

The present invention will be described in detail with reference to specific examples. It should be noted that the following examples are only illustrative of the present invention, but the scope of the present invention is not limited to the following examples.

The preparation method of the EuS NCs nano composite material adopts a one-step method to prepare the composite nano material, and is shown in figure 1.

Example 1

Preparation of EuS NCs:

mixing EuCl₃·6H₂O (0.1466g), 1-octadecene (10.0mL), N-dodecyl mercaptan (6mL), oleylamine (3.4mL) and oleic acid-400 (0.88mL) were mixed in an autoclave, and vacuum was applied at 100 ℃ for 2h with continuous stirring, followed by 200 ℃ and N₂And reacting for 3 hours under the environment of (1). When the solution is cooled to room temperature, precipitating and centrifuging for 3-5 times with a mixture of methanol and acetone (volume ratio of 1: 4), wherein the rotation speed is 8000-10000r/min, and the time is 10min, and removing unreacted organic matters. Finally, the washed EuS NCs were dispersed in CCl₄And (5) putting the mixture into a refrigerator for storage.

Step 2, preparing HgCl with different concentrations₂Solution (0.01)fM-100nM) and put into a refrigerator for standby.

And 3, adding part of ultrapure water into the marine product meat, crushing the marine product meat, centrifuging the marine product meat for 6min at the rotating speed of 9000r/min, filtering to obtain a supernatant, and standing for later use.

Example 2

Preparation of EuS NCs electrochemiluminescence sensor

(1) The Glassy Carbon Electrode (GCE) was coated with 0.5 μm and 0.03 μm Al, respectively₂O₃Grinding and polishing the powder on chamois leather for 3-5 min. And ultrasonically cleaning the polished GCE for three times by using ultrapure water, wherein the ultrasonic cleaning is carried out for 3min each time. After ultrasonic cleaning, the mixture is washed in a solvent containing 1mmol/L K₃[Fe(CN)₆]Performing CV scanning in KCl solution of 0.1mol/L, setting scanning potential to-0.2-0.6V, and finishing electrode polishing when the difference value between oxidation peak potential and reduction peak potential is less than 100 mV.

(2) Naturally drying the polished electrode in the step (1), uniformly modifying the surface of the GCE with 5 mu L of EuS NCs dispersion liquid by using a 0.5-10 mu L pipette gun, and then placing the EuS NCs/GCE in a shady place for drying in the shade.

The nano composite material modified electrode is used for constructing an electrochemical luminescence sensor to detect Hg²⁺The concentration of (c).

The detection method is an electrochemical luminescence method, and the detection device is an MPI-E type electrochemiluminescence analysis system. The glassy carbon electrode modified by the nano composite material prepared in the embodiment 2 of the invention is used as a working electrode in a three-electrode system, an Ag/AgCl (saturated KCl) electrode is used as a reference electrode, and a platinum wire electrode is used as an auxiliary electrode. The co-reactant is 50mM K₂S₂O₈0.1M PBS coreactant (pH 7.4). Different concentrations of HgCl as in example 2₂Solution K₂S₂O₈Mixing the co-reactants with equal volume, and detecting Hg²⁺。

The detection conditions of the cyclic voltammetry are as follows: 50mM K₂S₂O₈0.1M PBS coreactant (pH 7.4) mixed solution, scanning potential-2.0-0V, scanning rate 0.1V/S, photomultiplier high pressure 800V.

The structural morphology of each nano material is characterized, and the result is good.

The specific characterization method comprises the following steps:

FIG. 2, FIG. 2A is a Transmission Electron Micrograph (TEM) of EuS NCs according to the present invention, and FIG. 2B is a graph of particle size analysis. From the two figures, it can be seen that the composite nano-material is single and dispersed, and the particle size is mostly distributed around 10-12 nm.

FIG. 3 is an energy spectrum analysis (EDS) of the EuS NCs composite material according to the present invention. It can be seen from FIG. 3 that Eu, S, etc. are present.

Referring to fig. 4, which is an X-ray diffraction pattern (XRD) of the EuS NCs composite according to the present invention, it can be seen from fig. 4 that several diffraction peaks appear at 25.9 °, 29.93 ° and 53.11 °, respectively. Respectively, the (111) crystal plane (lattice spacing) of the corresponding face-centered cubic crystal form EuS

) Crystal plane (lattice spacing) of (200)

) And (222) plane (lattice spacing)

). A distinct hetero-peak, which is a peak of the element C, appears at 43.9 ° because the heating temperature is too high, causing carbonization.

FIG. 5 is a Fourier transform infrared (FT-IR) spectrum of the EuS NCs composite according to the present invention. The peak of the stretching vibration of O-H is 3442cm^-1In-plane deformation vibration peak of 1380cm^-1. CH in oleic acid chain₂The peak corresponding to the peak of stretching vibration of (2) is 2917cm^-1。1630cm^-1Corresponds to the symmetric oscillation peak of C ═ C in 1-octadecene.

Referring to FIG. 6, which is a fluorescence spectrum of the EuS NCs composite material according to the present invention, it can be seen from FIG. 6 that the EuS NCs exhibits blue fluorescence at an excitation wavelength of about 425nm, and the fluorescence is blue-shifted due to the small particle size.

The modified electrode is subjected to conventional electrochemical performance tests, and the result is good.

Comparative example 1

Preparation of electrochemiluminescence sensor

Comparative example 1 was prepared in the same manner as in example 2. Except that a glassy carbon electrode was directly used as the working electrode in the three-electrode system. The EuS NCs was prepared according to the same procedure as in example 1.

Comparative example 2

Preparation of electrochemiluminescence sensor

Comparative example 2 was prepared in the same manner as in example 2. The only difference is that the EuS NCs modified electrode was used as the working electrode in a three-electrode system.

The EuS NCs was prepared according to the same procedure as in example 1.

The preparation method of the EuS NCs modified electrode comprises the following steps: EuS NCs modified electrodes were prepared in the manner described in example 1 in conjunction with example 2.

Further obtain better experimental conditions for K₂S₂O₈The optimum pH of the sample was 7.38 and the optimum pH of the sample in vivo was 7.4 as shown in the line graph of FIG. 7. Therefore, K used in the present invention₂S₂O₈The pH was 7.4.

See FIG. 8, ECL sensors constructed for EuS NCs composites according to the present invention for different concentrations of Hg²⁺Linear graph of (a). Preparing Hg with different concentrations²⁺From FIG. 8A, it can be seen that from 0.01fM to 100nM, from FIG. 8, it can be seen that with Hg²⁺The increase in concentration, as seen in fig. 8B, increases the degree of quenching of the ECL sensor.

See fig. 9, for: FIG. 9A ECL stability plot of EuS NCs composites, it can be seen from FIG. 9A that the stability of the sensor is good for detecting Hg²⁺Has great benefits. FIG. 9B ECL reproducibility of EuS NCs composites, the nano-material was tested with different electrodes and the reproducibility was better.

FIG. 10 shows the selectivity of EuS NCs composites of the present invention for other interfering ions. The sensor prepared by the invention can clearly distinguish target ions and interfering ions, which shows that the material has higher selectivity.

The EuS NCs composite material electrochemiluminescence sensor of the invention carries out labeling detection results on different marine products, and the results are shown in Table 1:

TABLE 1

Sample (I)	Adding scalar quantity (pM)	Measured value (pM)	Recovery (%)	RSD(％)
					Fish	10^-5	0.89×10^-5	89.13	3.3
	1	1.05	104.7	2.2
						10⁵	0.89×10⁵	88.72	3.3
Conch	10^-5	0.85×10^-5	85.11	2.3
						1	1.07	107.1	2.6
	10⁵	0.91×10⁵	90.78	0.6
					Shrimp (shrimp)	10^-5	0.87×10^-5	87.10	3.4
	1	1.07	107.2	3.2
						10⁵	0.90×10⁵	89.53	3.3

The data from table 1 show: the recovery rate of the marked fish sample is 87.1-117.5%, and the RSDs is 2.2-3.3%; the recovery rate of the marked conch sample is 83.24-117.2%, and RSDs is 0.6-2.6%; the recovery rate of the marked shrimps is 87.12-117.4%, and the RSDs is 3.2-3.4%. The results show that the EuS NCs ECL sensor constructed by the invention has Hg of the actual sample²⁺The detection has good applicability.

The information on the instruments and materials involved in the examples of the present invention is as follows

In comparative example 1, glassy carbon electrodes were purchased from Shanghai Chenghua instruments, Inc.;

other materials of this application were purchased from Aladdin reagent (Shanghai) Co., Ltd and Tianjin Hengxing chemical preparation Co., Ltd.

The invention is a label-free sensor, and only one layer of EuS NCs is needed to be directly oxidized for response, thus realizing high sensitivity and high selectivity.

The novel sensor prepared by the invention has excellent electrocatalytic activity to EuS NCs, and has the remarkable advantages of low detection limit, high sensitivity, good anti-interference performance and the like. The EuS NCs electrochemical sensor constructed based on the method is simple to prepare, low in cost and wide in application prospect in the aspect of protecting the environment and an ecological system.

The foregoing description of specific embodiments of the present invention has been presented. It is to be understood that the present invention is not limited to the specific embodiments described above, and that various changes or modifications may be made by one skilled in the art within the scope of the appended claims without departing from the spirit of the invention.

Claims

1. For Hg²⁺A method for preparing a detection electrochemiluminescence sensor is characterized in thatThe method comprises the following steps:

step 1, preparation of europium sulfide nanocrystals:

step 2, preparing a sensor:

and 4, carrying out detection analysis.

2. The method of claim 1 for Hg²⁺The preparation method of the detected electrochemiluminescence sensor is characterized in that in the step 1, the preparation of the europium sulfide nanocrystal comprises the following steps:

0.1466g of EuCl₃·6H₂O, 10mL of 1-octadecene, 6mL of n-dodecyl mercaptan and 0.88mL of oleic acid-400 are mixed in a high-pressure reaction kettle, and the mixture is continuously stirred and vacuumized for 2 hours at 100 ℃; at 200 ℃ and N₂Reacting for 3 hours in the environment; when the solution is cooled to room temperature, using a mixture of methanol and acetone according to the volume ratio of 1:4 to precipitate and centrifuge for 3-5 times, wherein the rotating speed is 8000-10000r/min, and the time is 10min, and removing unreacted organic matters to obtain europium sulfide nano-crystals; dispersing the washed europium sulfide nano-crystal into CCl₄And (5) putting the mixture into a refrigerator for storage and standby.

3. The method of claim 1 for Hg²⁺The preparation method of the detected electrochemiluminescence sensor is characterized in that in the step 2, the preparation of the sensor specifically comprises the following steps:

4. The method of claim 1 for Hg²⁺Preparation of electrochemiluminescence sensor for detectionThe method is characterized in that in the step 4, the detection and analysis specifically comprises the following steps: taking 1mL of supernatant and 3mL of 50mM K₂S₂O₈Mixing with 0.1M PBS coreactant, detecting ECL in MPI-E type electrochemiluminescence analysis system by europium sulfide nanocrystalline, and verifying existence of Hg in marine products²⁺Are present.

5. Use as claimed in claim 2 for Hg²⁺The preparation method of the detected electrochemiluminescence sensor is characterized in that 1-octadecene is a solvent; the eluent is a mixture of methanol and acetone according to a volume ratio of 1: 4.

6. The method of claim 1 for Hg²⁺The preparation method of the electrochemiluminescence sensor for detection is characterized in that the marine products are marine fishes, conchs and mantis shrimps.

7. The method of claim 4 for Hg²⁺A method of making a detection electrochemiluminescence sensor, wherein the co-reagent has a pH of 7.4.

8. The method of claim 4 for Hg²⁺The preparation method of the detected electrochemiluminescence sensor is characterized in that in the step 4, the working potential is-2.0-0V, the high voltage of a photomultiplier of an electrochemical workstation is 800V, and the scanning rate of the electrochemical workstation is 0.1V/S.