CN115386369B

CN115386369B - Preparation method of fluorescent probe for nickel ion detection

Info

Publication number: CN115386369B
Application number: CN202211015183.5A
Authority: CN
Inventors: 贾坤; 范子林; 冉启蒙; 刘孝波
Original assignee: University of Electronic Science and Technology of China
Current assignee: University of Electronic Science and Technology of China
Priority date: 2022-08-23
Filing date: 2022-08-23
Publication date: 2023-08-11
Anticipated expiration: 2042-08-23
Also published as: CN115386369A

Abstract

A preparation method of a fluorescent probe for nickel ion detection belongs to the technical field of high polymer materials. According to the invention, melamine modified nitrile resin is used as a precursor, and the nitrogen-doped carbon dot fluorescent probe is prepared after the reaction with nitric acid, so that the photoluminescence characteristic of the fluorescent probe is effectively enhanced, and the detection performance of the fluorescent probe on nickel ions is remarkably improved; the obtained nitrogen-doped carbon quantum dot is provided with oxygen-containing groups (such as carboxyl, nitro and the like) and can carry out coordination reaction with nickel ions, so that the detection effect is excellent, and the detection limit is 1.58nmol/L.

Description

Preparation method of fluorescent probe for nickel ion detection

Technical Field

The invention belongs to the technical field of high polymer materials, and particularly relates to a preparation method of a fluorescent probe for nickel ion detection.

Background

Along with the acceleration of the social industrialization process, the emission of waste water and waste gas of factories is increased, and heavy metal pollution is increasingly serious. Nickel contamination is also one of the problems that are urgently needed to be solved in the current generation. Nickel can enter the human body through the ways of respiratory tract, alimentary canal, skin contact and the like, is distributed and accumulated in a plurality of organ tissues of the whole body, inhibits the development of immune organs through excessively inducing apoptosis and inhibiting proliferation, or combines with DNA of the human body, inhibits the occurrence of certain enzymes, induces the action of synthesizing active oxygen and the like, causes corresponding dysfunction and has adverse effects on the health of the human body. Therefore, it is of great importance to develop a sensitive analytical tool capable of effectively detecting the concentration of trace heavy metal ions.

Currently, commonly used nickel ion detection methods include spectrophotometry, atomic absorption (FAAS), atomic emission spectrometry (ICP-AES), plasma mass spectrometry (ICP-MS), electrochemical analysis, liquid chromatography (HPLC), X-ray fluorescence spectrometry, and the like. However, spectrophotometry has low sensitivity and poor selectivity, and spectrum overlapping interference is often generated; the sensitivity of FAAS is not high; in addition, ICP-AES, ICP-MS is sensitive in detection but expensive in equipment; the reproducibility of the electrochemical analysis method is poor; HPLC procedures are cumbersome and require conversion of nickel ions to organic complexes or chelates prior to testing. In summary, the existing detection methods have the defects of expensive detection instruments, inconvenient carrying, complex sample preparation, no large-scale detection and the like. Therefore, the method which is rapid, convenient, low in cost, simple, reliable and convenient for on-site detection is developed, and is also a research hotspot in the current heavy metal ion detection field.

Carbon quantum dots (CDs) are a novel fluorescent material, and have the advantages of simple synthesis method, good photochemistry and photophysical properties and excellent biocompatibility, so that the carbon quantum dots are widely paid attention to by researchers. However, most of the carbon dots reported at present have weak photoluminescence characteristics, so that the detection sensitivity and the detection range are obviously limited. Thus, the above drawbacks prevent their further application in the field of detection.

Disclosure of Invention

The invention aims at solving the problems existing in the background technology and provides a preparation method of a fluorescent probe for nickel ion detection. According to the invention, melamine modified nitrile resin (MA-PH) is used as a precursor, and the nitrogen doped carbon dot fluorescent probe is prepared after the reaction with nitric acid, so that the photoluminescence characteristic of the fluorescent probe is effectively enhanced, and the detection performance of the fluorescent probe on nickel ions is remarkably improved.

In order to achieve the above purpose, the technical scheme adopted by the invention is as follows:

the preparation method of the fluorescent probe for nickel ion detection comprises the following steps:

step 1, uniformly mixing 18.1 parts by mass of bisphenol A, 10 parts by mass of formaldehyde, 1-3 parts by mass of melamine, 33.6 parts by mass of 3-aminophenoxy phthalonitrile, 34.2 parts by mass of toluene and 11.4 parts by mass of ethanol, and reacting at 80 ℃ for 4 hours to obtain melamine modified nitrile resin (MA-PH);

step 2, mixing and stirring 0.00025-0.001 part (the amount of substances) of melamine modified nitrile resin (MA-PH) prepared in the step 1, 0.05 part (mass) of nitric acid (98%) and 10 parts (mass) of deionized water for more than 30min, transferring into a hydrothermal kettle, reacting for 10-12 h at 180-220 ℃, naturally cooling to room temperature, and filtering supernatant to obtain carbon quantum dot solution (N-CDs);

step 3, adding deionized water into the carbon quantum dot solution (N-CDs) obtained in the step 2 for mixing and diluting, wherein the volume ratio of the carbon quantum dot solution (N-CDs) to the deionized water is 1:8, obtaining the fluorescent probe.

Wherein, the chemical structural formula of the 3-aminophenoxy phthalonitrile is as follows:

wherein the melamine modified nitrile resin (MA-PH) has the chemical structural formula:

compared with the prior art, the invention has the beneficial effects that:

1. according to the preparation method of the fluorescent probe for nickel ion detection, melamine modified nitrile resin (MA-PH) is used as a precursor, and the nitrogen-doped carbon point fluorescent probe is prepared after the reaction with nitric acid, so that the photoluminescence characteristic of the fluorescent probe is effectively enhanced, and the detection performance of the fluorescent probe on nickel ions is remarkably improved.

2. According to the preparation method of the fluorescent probe for nickel ion detection, the obtained nitrogen-doped carbon quantum dot is provided with oxygen-containing groups (such as carboxyl, nitro and the like) and can carry out coordination reaction with nickel ions, so that the detection effect is excellent, and the detection limit is 1.58nmol/L.

3. The preparation method of the fluorescent probe for nickel ion detection provided by the invention is simple, safe and environment-friendly, and the fluorescent probe with excellent performance is prepared by optimizing the raw materials and the technological parameters such as the proportion thereof, the reaction temperature time and the like.

Drawings

FIG. 1 is an infrared spectrum of a melamine modified nitrile resin (MA-PH) obtained in step 1 of example 1;

FIG. 2 is a fluorescence spectrum of the carbon quantum dots (N-CDs) prepared in examples 1,2 and 3;

FIG. 3 is a graph showing fluorescence spectra of the carbon quantum dot solution (N-CDs) prepared in the step 2 of example 1 under different ultraviolet light irradiation;

FIG. 4 is an infrared spectrum of the fluorescent probe prepared in the step 3 of the example 1 after the nickel ion solution is added to the fluorescent probe;

FIG. 5 shows the response and linear range of the fluorescent probe prepared in step 3 of example 1 to nickel ions of different concentrations;

FIG. 6 shows the reproducibility of the detection of nickel ion concentration by the fluorescent probe prepared in step 3 of example 1;

FIG. 7 shows fluorescence emission spectra of the fluorescent probe prepared in step 3 of example 1 in different 10. Mu.M metal ion solutions.

Detailed Description

The present invention is further illustrated by the following description of specific embodiments, which are not intended to be limiting, and various modifications or alterations can be made by those skilled in the art based on the basic idea of the invention without departing from the scope of the invention.

Example 1

Step 1, uniformly mixing 11.4g of bisphenol A, 6.3g of formaldehyde, 0.63g of melamine, 21.15g of 3-aminophenoxy phthalonitrile, 21.52g of toluene and 7.17g of ethanol, reacting for 4 hours at 80 ℃, then drying for 2 hours at 60 ℃ in a blast oven to obtain melamine modified nitrile resin (MA-PH), and grinding for later use; the infrared spectrum is shown in figure 1;

step 2, taking 0.3g of melamine modified nitrile resin (MA-PH) prepared in the step 1, 50 mu L of nitric acid (98%) and 10mL of deionized water, placing the materials in a 20mL strain bottle, mixing and stirring for more than 30min, transferring the materials into a hydrothermal kettle, reacting for 10h at 200 ℃, naturally cooling to room temperature, and filtering supernatant to obtain a carbon quantum dot solution (N-CDs);

FIG. 3 is a graph showing fluorescence spectra of the carbon quantum dot solution (N-CDs) prepared in the step 2 of example 1 under different ultraviolet light irradiation; as can be seen from fig. 3, the fluorescence intensity of the carbon quantum dot N-CDs remained substantially stable as the irradiation time increased.

FIG. 4 is an infrared spectrum of the fluorescent probe prepared in the step 3 of example 1 after adding nickel ion solution to the fluorescent probe. As can be seen from FIG. 4, the absorption peak of the hydroxyl group and the absorption peak of the carbonyl group of the fluorescent probe move after the nickel ion solution is added, which indicates that the carboxyl group coordinates with the nickel; and the absorption peak of the nitro has obvious displacement before and after the fluorescent probe is added into the nickel ion solution, which indicates that the nitro and the nickel are coordinated.

FIG. 5 shows the response and linear range of the fluorescent probe prepared in step 3 of example 1 to nickel ions of different concentrations; as can be seen from FIG. 5, by linearly fitting the fluorescence response of the fluorescent probe to nickel ions of different concentrations, a certain linear relationship is found, and R ² = 0.99437. To further demonstrate the reproducibility of the detection of the fluorescent probe, it was used to detect nickel ion solutions of specific concentrations, and the degree of fluorescence quenching detected at each concentration was substituted into the linear equation fitted in fig. 5, and the test concentration was calculated and compared with the calibration concentration, and the detection result was shown in fig. 6. FIG. 6 shows that the multiple detection results at each concentration are close to the actual nickel ion concentration, and the standard deviation of the test results is below 0.5, which indicates that the fluorescent probe has excellent reproducibility for the detection of nickel ions.

FIG. 7 is a fluorescence emission spectrum of the fluorescent probe prepared in step 3 of example 1 in different 10. Mu.M metal ion solutions; as can be seen from fig. 7, the quenching rate of the carbon quantum dots in the 10 μm different metal ion solutions was lower than that of the nickel ions, and the selectivity was good.

Example 2

This embodiment differs from embodiment 1 in that: the temperature of the hydrothermal reaction in the step 2 is adjusted to 180 ℃; the remaining steps are exactly the same as in example 1.

Example 3

This embodiment differs from embodiment 1 in that: the temperature of the hydrothermal reaction in the step 2 is adjusted to 220 ℃; the remaining steps are exactly the same as in example 1.

Claims

1. The preparation method of the fluorescent probe for nickel ion detection is characterized by comprising the following steps of:

step 1, uniformly mixing 18.1 parts by mass of bisphenol A, 10 parts by mass of formaldehyde, 1-3 parts by mass of melamine, 33.6 parts by mass of 3-aminophenoxy phthalonitrile, 34.2 parts by mass of toluene and 11.4 parts by mass of ethanol, and reacting at 80 ℃ for 4 hours to obtain melamine modified nitrile resin;

step 2, mixing and stirring the melamine modified nitrile resin prepared in the step 1, 0.05 part by mass of nitric acid and 10 parts by mass of deionized water for more than 30 minutes according to the mass part of 0.00025-0.001 substance, transferring the mixture into a hydrothermal kettle, reacting for 10-12 hours at 180-220 ℃, naturally cooling to room temperature, and filtering supernatant fluid to obtain a carbon quantum dot solution;

and 3, adding deionized water into the carbon quantum dot solution obtained in the step 2 for mixing and diluting, wherein the volume ratio of the carbon quantum dot solution to the deionized water is 1:8, obtaining the fluorescent probe.