Fluorescent analysis system for specific response to p-nitrophenol based on gold nanoclusters AuNCs@CFP

Abstract

The application discloses a fluorescence analysis system for specific response to p-nitrophenol based on gold nanoclusters AuNCs@CFP, 200 muL of gold nanoclusters AuNCs@CFP, 500 muL of PB buffer solution with pH=10 and to-be-detected p-nitrophenol are diluted to 4 mL, the fluorescence intensity of the mixture is determined at an excitation wavelength of 334 nm after reaction at 45 DEG C for 50 min, the concentration of the to-be-detected p-nitrophenol is calculated according to the determined fluorescence intensity and a regression equation, the linear concentration range of the p-nitrophenol is 1.25-40 muM, the regression equation is F0 / F i =0.0258C+1.0003, F0 and F i are the fluorescence intensities of the mixture before and after the addition of the p-nitrophenol respectively, the correlation coefficient R 2 =0.9922, the detection limit LOD is 1.92 muM, the concentration of the p-nitrophenol is 25 muM, the relative standard deviation RSD is 1.13% in 11 repeated determinations. The preparation method of the gold nanoclusters AuNCs@CFP in the application is simple and easy to synthesize, and the fluorescence performance of the gold nanoclusters AuNCs@CFP is excellent.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of construction of a fluorescence analysis system for specifically responding to p-nitrophenol, and particularly relates to a fluorescence analysis system for specifically responding to p-nitrophenol constructed based on gold nanoclusters AuNCs@CFP. BACKGROUND

[0002] P-nitrophenol (4-NP) is widely used in pesticide synthesis, dye processing, leather coloring, wood preservation, drug synthesis and explosives, etc. Although it is widely used, it is considered as a highly dangerous phenol in organic matters due to its carcinogenicity, genotoxicity and skin disease. Therefore, it is necessary to develop an effective and simple analysis method for high-sensitivity detection of p-nitrophenol. The reported detection methods, including high-performance liquid chromatography, ultraviolet-visible spectrophotometry, capillary electrophoresis and fluorescence method, are used for determination of p-nitrophenol in environmental water samples. Most of these methods are relatively expensive, time-consuming, complex and require a large amount of organic solvent. The fluorescence analysis method based on nanoclusters provides a new choice for detection of p-nitrophenol. SUMMARY

[0003] The technical problem solved by the application is to provide a fluorescence analysis system for specifically responding to p-nitrophenol constructed based on gold nanoclusters AuNCs@CFP, which has fast response, high sensitivity and good selectivity. The preparation method of the gold nanoclusters in the fluorescence analysis system is simple, easy to synthesize and has excellent fluorescence performance.

[0004] 1. The fluorescence analysis system for specifically responding to p-nitrophenol constructed based on gold nanoclusters AuNCs@CFP, characterized in that 200 µL of gold nanoclusters AuNCs@CFP, 500 µL of PB buffer solution with pH=10 and the to-be-detected p-nitrophenol are diluted to 4 mL, and the fluorescence intensity is measured at an excitation wavelength of 334 nm after reaction at 45°C for 50 min, and the concentration of the to-be-detected p-nitrophenol is calculated according to the measured fluorescence intensity and a regression equation; the linear concentration range of the p-nitrophenol is 1.25-40 µM, the regression equation is F0 / F i =0.0258C+1.0003, F0 and F i are the fluorescence intensities of the mixed system before and after addition of the p-nitrophenol, the correlation coefficient R 2 =0.9922, the detection limit LOD is 1.92 µM, the concentration of the p-nitrophenol is 25 µM, the relative standard deviation RSD is 1.13% in 11 repeated determinations;

[0005] The specific preparation process of the gold nanocluster AuNCs@CFP is as follows: 0.5 mL of 24.28 mM HAuCl4 solution is taken in a 50 mL round-bottom flask, 8.28 mL of pure water is added, and stirring is carried out while heating, 1.22 mL of 5 mM cefoperazone sodium is added after the solution is boiled, and the reaction is continued for 11 h, and then cooled to room temperature, 0.45 µm hydrophilic PTFE is used for filtration, and finally the synthesized gold nanocluster AuNCs@CFP is stored in a 4℃ refrigerator for standby.

[0006] Preferably, the common phenolic compounds have no response to the constructed fluorescence analysis system, and the common phenolic compounds do not interfere with the determination of p-nitrophenol, which indicates that the fluorescence analysis system based on the gold nanocluster AuNCs@CFP has strong selectivity and strong anti-interference ability for specific response to p-nitrophenol, wherein the common phenolic compounds are one or more of 2-nitrophenol, o-aminophenol, p-aminophenol, m-aminophenol, 3-nitrophenol, bisphenol A, p-acetylaminophenol or benzoic acid.

[0007] Preferably, the fluorescence analysis system is used for analyzing the filtered surface water sample, no p-nitrophenol is detected in the surface water sample, the standard addition recovery of p-nitrophenol is between 99.10%-102.87%, and the relative standard deviation RSD is between 0.42%-3.21%, which indicates that the constructed fluorescence analysis system can be successfully used for selective determination of p-nitrophenol in the surface water sample.

[0008] The preparation method of the gold nanocluster AuNCs@CFP in the application is simple and easy to synthesize, and the fluorescence performance of the gold nanocluster AuNCs@CFP is excellent, the linear concentration range of p-nitrophenol is 1.25-40 µM, the correlation coefficient R 2 =0.9922, the relative standard deviation is 1.13%, and the detection limit is 1.92 µM, which can be successfully applied to the specific detection of p-nitrophenol in the surface water sample. BRIEF DESCRIPTION OF DRAWINGS

[0009] Figure 1 is the influence of storage time on the fluorescence performance of the gold nanocluster AuNCs@CFP. The fluorescence intensity value of the gold nanocluster AuNCs@CFP almost does not change after being stored in a refrigerator at 4℃ for 50 days.

[0010] Figure 2 is the influence of pH on the fluorescence performance of the gold nanocluster AuNCs@CFP. The fluorescence intensity of the gold nanocluster AuNCs@CFP almost does not change when the pH is in the range of 4-7. The fluorescence intensity slightly decreases as the pH value continues to increase.

[0011] Figure 3Effect of sodium chloride concentration on the fluorescence properties of gold nanoclusters AuNCs@CFP. The fluorescence intensity of the fluorescence analysis system did not change significantly when the sodium chloride concentration was in the range of 50-300mM.

[0012] Figure 4 Effect of exposure time on the fluorescence properties of gold nanoclusters AuNCs@CFP. The fluorescence intensity of gold nanoclusters AuNCs@CFP did not change significantly after 60min of UV light irradiation.

[0013] Figure 5 Excitation and emission spectra of gold nanoclusters AuNCs@CFP. The maximum excitation and emission peaks of gold nanoclusters AuNCs@CFP were at 334nm and 382nm, respectively.

[0014] Figure 6 Emission spectra of gold nanoclusters AuNCs@CFP at different excitation wavelengths. The excitation wavelength increased from 319nm to 349nm, and the position of the emission peak of gold nanoclusters AuNCs@CFP hardly moved, indicating that the size of gold nanoclusters AuNCs@CFP was small and uniform.

[0015] Figure 7 Infrared spectra of cefoperazone sodium CFP and gold nanoclusters AuNCs@CFP. There were subtle differences between the infrared spectra of cefoperazone sodium and gold nanoclusters AuNCs@CFP, such as the absorption peak at 1658cm -1 which was caused by the asymmetric stretching vibration of -C=O in cefoperazone sodium. Due to the interaction between CFP and Au, a blue shift occurred in the infrared spectrum of gold nanoclusters AuNCs@CFP.

[0016] Figure 8 Selectivity and anti-interference performance of the determination method of the fluorescence analysis system. DETAILED DESCRIPTION

[0017] The above content of the present application is further described in detail through the following examples, but this should not be understood as limiting the scope of the above subject matter of the present application to only the following examples. Any technology realized based on the above content of the present application falls within the scope of the present application. EXAMPLE

[0018] Preparation of gold nanoclusters AuNCs@CFP

[0019] Take 0.5 mL HAuCl4 solution (24.28 mM) in a round-bottom flask (50 mL), add 8.28 mL of pure water, heated and stirred, after the solution is boiled, add 1.22 mL (5 mM) cefoperazone sodium (CFP), continue to react for 11 h, cool to room temperature, use 0.45 μm hydrophilic PTFE filter, finally the synthesized gold nanoclusters AuNCs@CFP are stored in the refrigerator (4℃) for standby.

[0020] Determination method of p-nitrophenol

[0021] Take 200 μL gold nanoclusters AuNCs@CFP, 500 μL PB buffer solution (pH=10) and a certain amount of p-nitrophenol to 4 mL. React at 45℃ for 50 min. At the excitation wavelength of 334 nm, the fluorescence intensity is determined. The linear concentration range of p-nitrophenol is 1.25-40 μM, the regression equation is F0 / F i =0.0258C+1.0003, F0 and F i are the fluorescence intensities of the system before and after adding p-nitrophenol, respectively, the correlation coefficient R 2 =0.9922, the detection limit (LOD) is 1.92 μM. The concentration of p-nitrophenol is 25 μM, and the relative standard deviation (RSD) is 1.13% for 11 repeated determinations.

[0022] Selectivity and anti-interference performance of p-nitrophenol determination method

[0023] In order to detect the selectivity and anti-interference performance of the p-nitrophenol fluorescence analysis method based on gold nanoclusters AuNCs@CFP, the effects of 2-nitrophenol (2-NP), o-aminophenol (2-AP), p-aminophenol (4-AP), m-aminophenol (3-AP), 3-nitrophenol (3-NP), bisphenol A (BPA), paracetamol (APAP), and benzoic acid (BA) on the determination system were investigated. Take 200 μL gold nanoclusters AuNCs@CFP and 500 μL PB buffer solution (pH=10), add 0.2 mL (500 μM) of the above investigated substances respectively, react at 45℃ for 50 min, and determine the fluorescence intensity of the system.

[0024] In order to detect the interference of the above-mentioned substances on the detection of p-nitrophenol, the same concentration (25µM) of the interfering substance was added to the detection system at a p-nitrophenol concentration of 25µM, and the reaction was carried out at 45℃ for 50 min. The fluorescence intensity of the system was then measured.

[0025] Depend on Figure 8 It can be seen that the fluorescence analysis system constructed based on the gold nanoclusters AuNCs@CFP synthesized in this invention specifically responds to p-nitrophenol, but has almost no response to common phenols and other substances investigated. Moreover, common phenols and other interfering substances do not interfere with the determination of p-nitrophenol. This indicates that the constructed fluorescence analysis system based on gold nanoclusters AuNCs@CFP has strong selectivity and strong anti-interference ability.

[0026] Application of fluorescence analysis system in surface water sample detection

[0027] The fluorescence analysis system based on gold nanoclusters (AuNCs@CFP) constructed in this invention was used to achieve fluorescence-specific recognition and analysis of p-nitrophenol. Filtered surface water samples were analyzed, and no p-nitrophenol was detected in the samples. The spiked recovery results are shown in Table 1. The recoveries ranged from 99.10% to 102.87%, and the relative standard deviations (RSDs) ranged from 0.42% to 3.21%. This indicates that the fluorescence analysis system based on gold nanoclusters (AuNCs@CFP) constructed in this invention can be successfully used for the selective determination of p-nitrophenol in surface water samples.

[0028] Table 1. Spiking recovery experiment of p-nitrophenol

[0029]

[0030] The foregoing has shown and described the basic principles, main features and advantages of the present invention. Various changes and modifications can be made to the present invention without departing from the spirit and scope thereof, and all such changes and modifications fall within the scope of the present invention as claimed.

Claims

1. A fluorescence analysis method for specific response to p-nitrophenol based on gold nanoclusters AuNCs@CFP, characterized in that: 200 µL of gold nanoclusters (AuNCs@CFP), 500 µL of PB buffer solution (pH=10), and the target p-nitrophenol were added and brought to a final volume of 4 mL. The mixture was reacted at 45 °C for 50 min, and the fluorescence intensity was measured at an excitation wavelength of 334 nm. The concentration of the target p-nitrophenol was calculated based on the measured fluorescence intensity and a regression equation. The linear concentration range of p-nitrophenol was 1.25–40 µM, and the regression equation was F0 / F0. i =0.0258C+1.0003, F0 and F i The fluorescence intensity and correlation coefficient R of the mixture before and after the addition of p-nitrophenol are shown respectively. 2 =0.9922, detection limit (LOD) is 1.92µM; The specific preparation process of the gold nanoclusters AuNCs@CFP is as follows: 0.5 mL of 24.28 mM HAuCl4 solution is taken in a 50 mL round-bottom flask, 8.28 mL of pure water is added, and the solution is heated and stirred, 1.22 mL of 5 mM cefoperazone sodium is added after the solution is boiled, and the reaction is continued for 11 h, and then cooled to room temperature, 0.45 µm hydrophilic PTFE is used for filtration, and finally the synthesized gold nanoclusters AuNCs@CFP are stored in a 4℃ refrigerator for standby.

2. The fluorescence analysis method for specific response to p-nitrophenol based on gold nanoclusters AuNCs@CFP construction according to claim 1, characterized in that: Common phenolic compounds have substantially no response to the constructed fluorescence analysis system, and the common phenolic compounds do not substantially interfere with the determination of p-nitrophenol, wherein the common phenolic compounds are one or more of 2-nitrophenol, o-aminophenol, p-aminophenol, m-aminophenol, 3-nitrophenol, bisphenol A, p-acetylaminophenol, or benzoic acid.

3. The fluorescence analysis method for specific response to p-nitrophenol based on gold nanoclusters AuNCs@CFP construction according to claim 1, characterized in that: The fluorescence analysis method is used for analyzing filtered surface water samples, no p-nitrophenol is detected in the surface water samples, the recovery rate of p-nitrophenol is between 99.10% and 102.87%, and the relative standard deviation RSD is between 0.42% and 3.21%.

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