CN115386369A

CN115386369A - Preparation method of fluorescent probe for nickel ion detection

Info

Publication number: CN115386369A
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: 2022-11-25
Anticipated expiration: 2042-08-23
Also published as: CN115386369B

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, the 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 obviously improved; the obtained nitrogen-doped carbon quantum dot has oxygen-containing groups (such as carboxyl, nitro and the like) and can perform a 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

With the acceleration of the social industrialization process, the discharge amount 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 is urgently needed to be solved in the present generation. Nickel can enter human body through respiratory tract, digestive tract, skin contact and other ways, is distributed and accumulated in multiple organ tissues of the whole body, inhibits the development of immune organs by over-inducing apoptosis and inhibiting proliferation, or is combined with human DNA, inhibits the generation of certain enzymes and induces the actions of synthesizing active oxygen and the like to cause corresponding dysfunction, thus causing adverse effects on human health. Therefore, it is of great significance to develop a sensitive analysis tool capable of effectively detecting the concentration of trace heavy metal ions.

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

Carbon quantum dots (CDs) are a new class of fluorescent materials, and have attracted extensive attention from researchers because of their simple synthesis method, good photochemical and photophysical properties, and excellent biocompatibility. However, most of the carbon dots reported at present have slightly weak photoluminescence characteristics, so that the detection sensitivity and the detection range are obviously limited. Therefore, the above disadvantages prevent further application in the field of detection.

Disclosure of Invention

The invention aims to provide a preparation method of a fluorescent probe for nickel ion detection, aiming at the problems in the background art. According to the invention, the 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 obviously improved.

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

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

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

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

wherein the chemical structural formula of the melamine modified nitrile resin (MA-PH) is as follows:

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, provided by 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.

2. According to the preparation method of the fluorescent probe for nickel ion detection, provided by the invention, the obtained nitrogen-doped carbon quantum dot has oxygen-containing groups (such as carboxyl, nitro and the like) and can perform 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 process parameters such as proportion, reaction temperature and 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 graph showing fluorescence spectra of carbon quantum dots (N-CDs) obtained in examples 1,2, 3;

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

FIG. 4 is a chart of infrared spectra of the fluorescent probe prepared in step 3 of example 1 and the fluorescent probe after addition of nickel ion solution;

FIG. 5 is a graph showing the response and linear range of fluorescent probes prepared in step 3 of example 1 to different concentrations of nickel ions;

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

FIG. 7 is 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 described in the following description of the specific embodiments, but the present invention is not limited thereto, and those skilled in the art can make various modifications or alterations based on the basic idea of the present invention without departing from the scope of the present 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 ℃, drying for 2 hours at 60 ℃ in a blast oven to obtain melamine modified nitrile-based 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 mixture in a 20mL strain bottle, mixing and stirring for more than 30min, then transferring the mixture into a hydrothermal kettle, reacting for 10h at 200 ℃, naturally cooling to room temperature, taking supernatant, and filtering to obtain a carbon quantum dot solution (N-CDs);

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

FIG. 4 is an infrared spectrum of the fluorescent probe prepared in step 3 of example 1 and the fluorescent probe after addition of nickel ion solution. 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 nickel; and the absorption peak of the nitro group has obvious displacement before and after the fluorescent probe is added into the nickel ion solution, which indicates that the nitro group and the nickel are coordinated.

FIG. 5 is the response and linear range of fluorescent probes prepared in step 3 of example 1 for different concentrations of nickel ions; as can be seen from FIG. 5, the fluorescence response of the fluorescent probe to nickel ions of different concentrations is linearly fitted, and R is found to have a certain linear relationship ² =0.99437. To further demonstrate the reproducibility of the detection of fluorescent probes, they were 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 to FIG. 5 to calculate the testThe concentration is compared with the calibration concentration, and the detection result is shown in FIG. 6. Fig. 6 shows that the results of multiple measurements at each concentration are close to the actual nickel ion concentration, and the standard deviation of the test results is below 0.5, indicating that the fluorescent probe has excellent reproducibility for the detection of nickel ions.

FIG. 7 is fluorescence emission spectra 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 μ M solution of different metal ions is lower than that of the nickel ions, and the selectivity is very good.

Example 2

This example is different from example 1 in that: the temperature of the hydrothermal reaction in the step 2 is adjusted to 180 ℃; the rest of the procedure was exactly the same as in example 1.

Example 3

This example is different from example 1 in that: adjusting the temperature of hydrothermal reaction in the step 2 to 220 ℃; the rest of the procedure was exactly the same as in example 1.

Claims

1. A preparation method of a fluorescent probe for nickel ion detection is characterized by comprising 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-based resin;

step 2, mixing and stirring 0.00025-0.001 part by mass of 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 30min, then transferring the mixture into a hydrothermal kettle, reacting for 10-12 h at 180-220 ℃, naturally cooling to room temperature, taking supernatant, and filtering to obtain a carbon quantum dot solution;

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