CN110530832B

CN110530832B - Method for selectively determining 2, 4-dinitrophenol in surface water sample based on fluorescence analysis

Info

Publication number: CN110530832B
Application number: CN201910787863.0A
Authority: CN
Inventors: 叶存玲; 王远飞; 孔欠欠; 王全坤; 王治科; 范顺利
Original assignee: Henan Normal University
Current assignee: Henan Normal University
Priority date: 2019-08-26
Filing date: 2019-08-26
Publication date: 2022-09-27
Anticipated expiration: 2039-08-26
Also published as: CN110530832A

Abstract

The invention discloses a method for selectively determining 2, 4-dinitrophenol in a surface water sample based on fluorescence analysis, which comprises the following specific steps: adding 0.3mL of AgNCs @ CAZ and 0.8mL of BR buffer solution with the pH =9 into a surface water sample to be detected, fixing the volume to 4mL, fully and uniformly mixing at room temperature, reacting for 50min, determining the fluorescence intensity of a mixed system at the excitation wavelength of 368nm, and then calculating the concentration of 2, 4-dinitrophenol in the surface water sample to be detected according to the determined fluorescence intensity and by combining a linear equation. According to the invention, AgNCs @ CAZ with high fluorescence intensity and good stability is synthesized by a simple and rapid method, and the AgNCs @ CAZ can perform specific response on 2, 4-dinitrophenol.

Description

Method for selectively determining 2, 4-dinitrophenol in surface water sample based on fluorescence analysis

Technical Field

The invention belongs to the technical field of fluorescence analysis, and particularly relates to a method for selectively determining 2, 4-dinitrophenol in a surface water sample based on fluorescence analysis.

Background

The metal fluorescent nano-cluster is an ideal fluorescent nano-material, wherein the silver nano-cluster has the characteristics of excellent fluorescence property, good water solubility, stability, biocompatibility and the like, so that the metal fluorescent nano-cluster is widely applied to a plurality of metal nano-clusters. However, the silver nanoclusters also have the disadvantage of being sensitive to the environment, for example, the silver nanoclusters cannot stably exist under high ionic strength and illumination conditions, so that further application of the silver nanoclusters in the fields of environmental detection and the like is limited.

Disclosure of Invention

The invention solves the technical problem of providing a method for selectively determining 2, 4-dinitrophenol in a surface water sample based on fluorescence analysis, which has the advantages of high speed, high efficiency, high selectivity and high sensitivity.

The invention adopts the following technical scheme for solving the technical problems, and the method for selectively determining the 2, 4-dinitrophenol in the surface water sample based on fluorescence analysis is characterized by comprising the following specific steps: taking 0.3mL of AgNCs @ CAZ and 0.8mL of BR buffer solution with the pH =9, adding a surface water sample to be detected, fixing the volume to 4mL, fully and uniformly mixing at room temperature, reacting for 50min, measuring the fluorescence intensity of a mixed system at an excitation wavelength of 368nm, and calculating the concentration of 2, 4-dinitrophenol in the surface water sample to be detected according to the measured fluorescence intensity and combining a linear equation; the linear concentration range of the 2, 4-dinitrophenol is 0.05-15 mu g/mL, and the linear equation is (F) ₀ -F)/F=0.1378C _2,4-DNP -0.0028 wherein F ₀ F is the fluorescence value before and after 2, 4-dinitrophenol is added at 368nm of the mixed system respectively, and the correlation coefficient R ² =0.9959, repeat 12 times of experimental measurements to obtain RSD of 0.9%, limit of detection LOD of 0.027 μ g/mL;

the specific preparation process of the AgNCs @ CAZ comprises the following steps of; 0.5mL of 10mM AgNO was taken ₃ Adding 4mL of 5mM ceftazidime CAZ solution into a jacketed beaker under vigorous stirring, diluting to 10mL, continuously stirring for reaction for 4 hours at 85 ℃ in a dark place, filtering by using a micro needle type filter, and finally storing the prepared AgNCs @ CAZ in a dark place at 4 ℃ for later use.

Preferably, the AgNCs @ CAZ is capable of specifically responding to 2, 4-dinitrophenol in aqueous solution in the presence of common phenolic compounds, wherein common phenolic compounds are 2-nitrophenol, 3-nitrophenol, p-aminophenol, m-aminophenol, p-acetaminophenol, o-aminophenol, catechol or/and benzoic acid.

According to the invention, AgNCs @ CAZ with high fluorescence intensity and good stability is synthesized by a simple and rapid method, and the AgNCs @ CAZ can perform specific response on 2, 4-dinitrophenol.

Drawings

FIG. 1 is a graph showing the effect of pH on the fluorescence properties of AgNCs @ CAZ.

FIG. 2 is a graph showing the effect of sodium chloride concentration on the fluorescence properties of AgNCs @ CAZ.

FIG. 3 is a graph of the effect of UV exposure time on the fluorescence properties of AgNCs @ CAZ.

FIG. 4 is the excitation and emission spectra of AgNCs @ CAZ.

FIG. 5 is an emission spectrum of AgNCs @ CAZ at different excitation wavelengths.

FIG. 6 is an infrared spectrum of AgNCs @ CAZ and Ceftazidime (CAZ).

FIG. 7 is a graph of the selectivity and interference rejection performance of the 2,4-DNP fluorometric method.

Detailed Description

The present invention is described in further detail below with reference to examples, but it should not be construed that the scope of the above subject matter of the present invention is limited to the following examples, and that all the technologies realized based on the above subject matter of the present invention belong to the scope of the present invention.

Examples

Preparation of AgNCs @ CAZ

0.5mL of 10mM AgNO was taken ₃ The solution is put into a jacketed beaker, 4mL of 5mM Ceftazidime (CAZ) solution is added under vigorous stirring, the volume is adjusted to 10mL, the solution is continuously stirred for 4 hours at 85 ℃ in the dark, a micro needle type filter is used for filtering, and finally the prepared AgNCs @ CAZ is stored at 4 ℃ in the dark for standby.

Determination of 2, 4-dinitrophenol (2, 4-DNP)

0.3mL of AgNCs @ CAZ and 0.8mL of BR buffer solution (pH = 9) are taken, a certain amount of 2,4-DNP is added, the volume is constant to 4mL, the mixture is fully and uniformly mixed at room temperature and then reacts for 50min, and the fluorescence intensity of the mixed system is measured at the excitation wavelength of 368 nm. The linear concentration range of 2,4-DNP is 0.05-15 mug/mL, and the linear equation is (F) ₀ -F)/F=0.1378C _2,4-DNP -0.0028, wherein F ₀ F respectively refers to the fluorescence value of the mixed system before and after 2,4-DNP is added at 368nm and the correlation coefficient R ² = 0.9959. The experiment was repeated 12 times to measure RSD of 0.9% and limit of detection (LOD) of 0.027. mu.g/mL.

Fluorescence performance and characterization of AgNCs @ CAZ

FIG. 1 is a graph showing the effect of pH on the fluorescence properties of AgNCs @ CAZ. The pH value examined has no significant influence on the AgNCs @ CAZ fluorescence intensity.

FIG. 2 is a graph showing the effect of sodium chloride concentration on the fluorescence properties of AgNCs @ CAZ. Increasing the NaCl concentration to 300mM did not significantly affect the AgNCs @ CAZ fluorescence intensity.

FIG. 3 is a graph of the effect of UV exposure time on the fluorescence properties of AgNCs @ CAZ. Irradiating with ultraviolet lamp for 10min, 30min, 60min, and 90min, and immediately measuring fluorescence intensity. The fluorescence intensity of AgNCs @ CAZ increases with the exposure time (0-60 min), and after 90min of irradiation, the fluorescence intensity tends to be stable, and the fluorescence intensity is 1.13 times of the initial fluorescence intensity. Therefore, the fluorescence intensity of AgNCs @ CAZ is greatly influenced by illumination, and the AgNCs @ CAZ needs to be stored away from light during storage.

FIG. 4 is the excitation and emission spectra of AgNCs @ CAZ. The maximum excitation peak of AgNCs @ CAZ is 368nm, and the maximum emission peak is 433 nm.

FIG. 5 is an emission spectrum of AgNCs @ CAZ at different excitation wavelengths. And scanning the corresponding fluorescence spectra of AgNCs @ CAZ at the excitation wavelengths of 338nm, 348nm, 358nm, 368nm and 378nm respectively. The AgNCs @ CAZ emission peak position does not change along with the change of the excitation wavelength, which shows that the synthesized AgNCs @ CAZ has uniform dispersion and uniform particle size.

FIG. 6 is an AgNCs @ CAZ and Ceftazidime (CAZ) infrared spectrum. The infrared spectrum of AgNCs @ CAZ is obviously different from the infrared spectrum of Ceftazidime (CAZ), which proves that AgNCs @ CAZ is successfully synthesized.

Determination of the Selectivity of the System

In order to examine the selectivity and the anti-interference performance of the 2,4-DNP fluorescence analysis method constructed by the invention, 0.3mL AgNCs @ CAZ and 0.8mL BR buffer solution (pH = 9) are taken, a certain amount of common interfering substances are added, and the volume is adjusted to 4 mL. The mixture is fully and evenly mixed at room temperature and then reacted for 50min, and the fluorescence intensity is measured at the excitation wavelength of 368 nm. The substances examined were 2-nitrophenol (2-NP), 3-nitrophenol (3-NP), p-aminophenol (PAP), m-aminophenol (MAP), acetaminophen (APAP), o-aminophenol (OAP), catechol (BPA), Benzoic Acid (BA).

Under the experimental conditions, the interference of the common phenols and the analogues thereof on the determination method is further examined. The concentration of 2,4-DNP was fixed at 10. mu.g/mL and an equal concentration of the phenolic interfering substance was added to each system. The results of the experiment are shown in FIG. 7. As can be seen from FIG. 7, the silver nanoclusters synthesized by the method can specifically respond to 2,4-DNP, and the constructed 2,4-DNP fluorescence analysis method is hardly interfered by the common phenols and the analogues thereof.

Detection of 2,4-DNP in actual surface water sample

And filtering the surface water sample for later use. A volume of water sample was added to 0.3mL of AgNCs @ CAZ and 0.8mL of BR buffer (pH = 9) to bring the volume to 4 mL. The mixture is fully and evenly mixed at room temperature and then reacted for 50min, and the fluorescence intensity of the mixed system is measured at the excitation wavelength of 368 nm. 2,4-DNP in the surface water sample is not detected. The results of the spiking experiments are shown in Table 1. RSD is between 0.10% and 0.81%, and the recovery rate of 2,4-DNP is between 96.66% and 99.91%. Therefore, the fluorescence analysis method for determining 2,4-DNP established by the invention is feasible for detecting the content of 2,4-DNP in the surface water sample.

TABLE 1 experimental results of standard recovery of 2,4-DNP in surface water sample

While there have been shown and described what are at present considered the fundamental principles of the invention, its essential features and advantages, the invention further resides in various changes and modifications which fall within the scope of the invention as claimed.

Claims

1. The method for selectively determining the 2, 4-dinitrophenol in the surface water sample based on fluorescence analysis is characterized by comprising the following specific steps: adding 0.3mL of AgNCs @ CAZ and 0.8mL of BR buffer solution with the pH =9 into a surface water sample to be detected, fixing the volume to 4mL, fully and uniformly mixing at room temperature, reacting for 50min, determining the fluorescence intensity of a mixed system at the excitation wavelength of 368nm, and calculating according to the measured fluorescence intensity and by combining a linear equation to obtainThe concentration of the 2, 4-dinitrophenol in the surface water sample to be detected is obtained; the linear concentration range of the 2, 4-dinitrophenol is 0.05-15 mu g/mL, and the linear equation is (F) ₀ -F)/F=0.1378C _2,4-DNP -0.0028 wherein F ₀ F is the fluorescence value before and after 2, 4-dinitrophenol is added at 368nm of the mixed system respectively, and the correlation coefficient R ² =0.9959, repeat 12 times of experimental measurements to obtain RSD of 0.9%, limit of detection LOD of 0.027 μ g/mL;

the specific preparation process of the AgNCs @ CAZ comprises the following steps of; 0.5mL of 10mM AgNO was taken ₃ The solution is put into a jacketed beaker, 4mL and 5mM ceftazidime CAZ solution are added under vigorous stirring, the volume is adjusted to 10mL, the reaction is continuously stirred for 4 hours at 85 ℃ in the dark, a micro needle type filter is used for filtering, and finally the prepared AgNCs @ CAZ is stored in the dark at 4 ℃ for standby.

2. The method for selectively determining 2, 4-dinitrophenol in a surface water sample based on fluorescence analysis according to claim 1, wherein: the AgNCs @ CAZ is capable of specifically responding to 2, 4-dinitrophenol in an aqueous solution in the presence of common phenolic compounds, wherein the common phenolic compounds are 2-nitrophenol, 3-nitrophenol, p-aminophenol, m-aminophenol, p-acetaminophenol, o-aminophenol, catechol or/and benzoic acid.