Dual-mode sensor based on composite metal organic framework as well as preparation method and application of dual-mode sensor

Abstract

The invention discloses a dual-mode sensor based on a composite metal organic framework as well as a preparation method and application of the dual-mode sensor. Zirconium oxychloride octahydrate, benzoic acid, iron (III)-tetra (4-carboxyl phenyl) chlorin and meso-tetra (4-carboxyl phenyl) porphin are used as raw materials, and the metal organic framework material is obtained through solvothermal reaction. Centrifuging, washing and dispersing in N, N-dimethylformamide to obtain a metal organic framework solution; heating and reacting with benzoic acid and zirconium oxychloride octahydrate to obtain a solution A; performing solvothermal reaction on the solution A, a 1, 3, 6, 8-tetra (4 '-carboxyphenyl) pyrene solution and trifluoroacetic acid to obtain a composite metal organic framework material; and washing, centrifuging and concentrating to obtain the dual-mode sensor. The dual-mode sensor has dual-emission fluorescence performance and nano-enzyme activity at the same time, and can act with phoxim to realize simultaneous dual-mode quantitative detection of phoxim.

Description

Technical Field

[0001] The invention belongs to the technical field of pesticide and veterinary drug residues and food safety detection, and specifically relates to a dual-mode sensor based on a composite metal organic framework and a preparation method and application thereof. Background Art

[0002] Pesticide residues have always been one of the food safety issues that people pay close attention to. Organophosphorus pesticides are one of the longest-used pesticides. They mainly damage the central nervous system of organisms by inhibiting the activity of acetylcholinesterase. In recent years, with the ban on the use of highly toxic organophosphorus pesticides, the use of phoxim has increased significantly. When phoxim enters water and soil, it is extremely difficult to decompose and will eventually enter the human body through biological cycles, further endangering human health. Therefore, accurate detection of phoxim residues is particularly urgent and important.

[0003] However, traditional detection methods have high instrument costs, and the pre-treatment steps are complicated and time-consuming. Most rapid detection methods for phoxim use single-reading technology, and slight changes in the detection environment, instruments, and operations can easily affect the reliability of the results. Compared with single-mode detection methods, dual-mode detection has more advantages.

[0004] The excellent pore structure and abundant active sites of metal-organic frameworks enable them to be composited with different materials, further improving the performance of metal-organic frameworks and producing new materials with excellent composite properties.

[0005] Therefore, it is of great significance to develop a dual-mode sensor based on metal-organic frameworks. Summary of the invention

[0006] Purpose of the invention: The purpose of the present invention is to provide a dual-mode sensor based on a composite metal organic framework and its preparation method and application in view of the deficiencies of the prior art. The dual-mode sensor based on the composite metal organic framework of the present invention has dual emission fluorescence performance and nanozyme activity at the same time, and can achieve simultaneous dual-mode quantitative detection of phoxim by reacting with phoxim.

[0007] Technical solution: The purpose of the present invention is achieved through the following technical solution:

[0008] The present invention provides a method for preparing a dual-mode sensor based on a composite metal organic framework, comprising the following steps:

[0009] (1) dissolving zirconium oxychloride octahydrate, benzoic acid, iron (III)-tetrakis(4-carboxyphenyl)porphyrin chloride and meso-tetrakis(4-carboxyphenyl)porphine in an organic solvent, and obtaining a metal organic framework material through a solvothermal reaction;

[0010] (2) centrifuging and washing the metal organic framework material obtained in step (1), and dispersing it in N,N-dimethylformamide to obtain a metal organic framework solution;

[0011] (3) dissolving the metal organic framework solution obtained in step (2), benzoic acid and zirconium oxychloride octahydrate in an organic solvent, mixing them evenly, heating them for reaction, and cooling them to room temperature after the reaction is completed to obtain a solution A;

[0012] (4) dissolving 1,3,6,8-tetrakis(4'-carboxyphenyl)pyrene in an organic solvent to obtain a solution B;

[0013] (5) mixing solution A obtained in step (3) and solution B obtained in step (4) uniformly, adding trifluoroacetic acid, and performing a solvent thermal reaction to obtain a composite metal organic framework material;

[0014] (6) Washing, centrifuging, and concentrating the composite metal organic framework material obtained in step (5) to obtain the dual-mode sensor.

[0015] Preferably, in step (1), the mass ratio of zirconium oxychloride octahydrate, iron (III)-tetrakis(4-carboxyphenyl)porphyrin chloride and meso-tetrakis(4-carboxyphenyl)porphine is 60:1.1:18.7; the mass ratio of zirconium oxychloride octahydrate and benzoic acid is 3:28; and the mass volume ratio of benzoic acid and organic solvent is 28:1 mg / mL.

[0016] Preferably, in step (1), the temperature of the solvent thermal reaction is 90° C.-110° C., and the reaction time is 4-6 h.

[0017] Preferably, in step (2), the centrifugation condition is 12000 rpm for 30 minutes.

[0018] Preferably, in step (3), the volume mass ratio of the metal organic framework solution to zirconium oxychloride octahydrate is 200:43.84 μL / mg; the mass volume ratio of benzoic acid to the organic solvent is 200:1 mg / mL; the temperature of the heating reaction is 90°C-110°C, and the heating reaction time is 1-2h.

[0019] Preferably, in step (4), the concentration of the 1,3,6,8-tetrakis(4'-carboxyphenyl)pyrene solution is 2.3-2.6 mg / mL.

[0020] Preferably, in step (5), the volume mass ratio of trifluoroacetic acid to 1,3,6,8-tetrakis(4'-carboxyphenyl)pyrene is 2:1 μL / mg; the temperature of the solvothermal reaction is 90° C.-110° C., and the reaction time is 4-6 h.

[0021] Preferably, the organic solvent is N,N-dimethylformamide containing 1% (v / v) water.

[0022] Preferably, in step (6), the centrifugation condition is 9500 rpm for 10 min.

[0023] Preferably, in step (6), the concentrated volume is 1 mL.

[0024] The present invention also provides a dual-mode sensor based on a composite metal organic framework prepared by the above preparation method. The dual-mode sensor of the present invention can be used as a composite probe.

[0025] The present invention also provides the use of the dual-mode sensor based on the composite metal organic framework in detecting phoxim. The dual-mode sensor of the present invention is a phoxim-specific sensor.

[0026] The present invention also provides a method for qualitatively detecting phoxim using a dual-mode sensor based on a composite metal organic framework: adding a phoxim liquid droplet onto the sensor, collecting a fluorescence spectrum, and detecting phoxim by taking the difference between a blank sample and a sample to be tested at 461±3 nm and the fluorescence peak value of the sample to be tested at 652±3 nm as a ratio; if the fluorescence peak at 461±3 nm is significantly quenched and the fluorescence peak value at 652±3 nm decreases slightly, phoxim is present; otherwise, phoxim is not present; the phoxim solution and acetylcholinesterase are first mixed, and then reacted with thioacetylcholine, TMB and hydrogen peroxide, and the absorbance value at 652 nm is measured; if ultraviolet absorption occurs, it is proved that phoxim is present; otherwise, phoxim is not present.

[0027] The present invention also provides a method for quantitatively detecting phoxim using a dual-mode sensor based on a composite metal organic framework: a phoxim sample solution and the dual-mode sensor solution are mixed, the fluorescence peaks at 461±3 nm and 652±3 nm are measured, a difference between a blank sample and a sample to be tested at 461±3 nm and a fluorescence peak of the sample to be tested at 652±3 nm are used as ratios to construct a linear relationship; a phoxim sample solution of known concentration is mixed with acetylcholinesterase for reaction, thioacetylcholine is added for mixed reaction, a concentrated solution of the dual-mode sensor, TMB, H2O2, and HAc-NaAc buffer are added, and after the reaction, the absorbance value at 652 nm is measured, and a linear relationship is constructed between the measured absorbance value and the phoxim concentration.

[0028] The qualitative and quantitative method of the invention is a method for detecting the content of phoxim by ratio fluorescence and colorimetry.

[0029] Preferably, the concentration of acetylcholinesterase is 0.5 U / mL.

[0030] Preferably, the concentration of the thioacetylcholine ATch aqueous solution is 12 mM.

[0031] Preferably, the concentration of the TMB aqueous solution is 30 mM.

[0032] Preferably, the concentration of hydrogen peroxide is 2M.

[0033] Beneficial effects:

[0034] The present invention constructs a dual-mode sensor for specifically detecting phoxim, and provides a phoxim detection method with strong specificity and high sensitivity by utilizing its fluorescence and nanozyme activity. The colorimetric mode can detect phoxim as low as 1.76 ng / mL, and a linear detection model can be constructed in the range of 2.5 ng / mL to 25 ng / mL. The ratio fluorescence mode can detect phoxim as low as 0.004 μg / mL, and a linear detection model can be constructed in the range of 0.005 μg / mL to 4 μg / mL, thereby providing a new and feasible method for trace detection of phoxim in complex systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is a transmission electron micrograph of the metal organic framework PCN222(Fe) synthesized in Example 1.

[0036] Figure 2 This is a scanning electron microscope image of the composite metal-organic framework synthesized in Example 1.

[0037] Figure 3 This is the ratio fluorescence response result of the dual-mode sensor in Example 2 for detecting phoxim.

[0038] Figure 4 This is the colorimetric signal response result of the dual-mode sensor in Example 2 for detecting phoxim. DETAILED DESCRIPTION

[0039] The technical solution of the present invention is described in detail below through specific embodiments, but the protection scope of the present invention is not limited to the embodiments.

[0040] Iron(III)-tetrakis(4-carboxyphenyl)porphyrin chloride, CAS number: 55266-17-6.

[0041] Example 1 Construction of ratiometric fluorescence-colorimetric dual-mode sensor based on composite metal organic framework PCN222(Fe)@NU-1000

[0042] (1) Synthesis of metal organic framework PCN222(Fe):

[0043] A 2 mL N, N-dimethylformamide solution (containing 1% v / v water) containing zirconium oxychloride octahydrate (6.0 mg), benzoic acid (56 mg), meso-tetrakis (4-carboxyphenyl) porphine (1.87 mg) and iron (III)-tetrakis (4-carboxyphenyl) porphyrin chloride (0.11 mg) was placed in a 5 mL round-bottom flask. After ultrasonic treatment at 25 ° C for 30 minutes, the mixture was incubated at 90 ° C for 5 hours. Finally, the product was collected by centrifugation (12000 rpm, 30 minutes), washed 3 times with N, N-dimethylformamide, and then dispersed in 1 mL N, N-dimethylformamide to obtain a metal organic framework PCN222 (Fe) solution, which was placed in a 4 ° C refrigerator for use.

[0044] Transmission electron microscopy images of PCN222(Fe) Figure 1 As shown in the figure, it can be seen that the size of PCN222(Fe) is about 200nm and presents a uniform columnar shape.

[0045] (2) Synthesis of composite metal-organic framework PCN222(Fe)@NU-1000:

[0046] Solution A: Weigh 43.84 mg of zirconium oxychloride octahydrate, 0.4 g of benzoic acid, take 200 μL of PCN222 (Fe) solution, add N, N-dimethylformamide solution (containing 1% v / v water), add the volume to 2 mL, and mix the solution by ultrasonic for 10 minutes. Heat the solution in a glass vial at 100°C for 1 hour. Take it out and cool it to room temperature.

[0047] Solution B: Weigh 5 mg of 1,3,6,8-tetrakis(4'-carboxyphenyl)pyrene and dissolve it in 2 mL of N,N-dimethylformamide. Mix by ultrasonication for 10 minutes.

[0048] Mix solution A and solution B, add 10 μL trifluoroacetic acid, mix by ultrasonic for 10 minutes, and continue heating at 100°C for 5 hours. Take out, wash 3 times with 4 mL N,N-dimethylformamide, centrifuge (9500 rpm, 10 min). Then concentrate to 1 mL to obtain the composite metal organic framework PCN222(Fe)@NU-1000 solution, and place it in a 4°C refrigerator for later use.

[0049] The scanning electron microscope image of PCN222(Fe)@NU-1000 is as follows Figure 2 As shown in the figure, it can be seen that the size of the composite material is about 500nm, and the size has obviously increased. Columnar tentacles have grown at both ends of the material, indicating that a new layer of material has grown on the shell of PCN222(Fe), which preliminarily characterizes the synthesis of the composite material.

[0050] Example 2 Ratio fluorescence-colorimetric dual-mode signal detection of phoxim

[0051] Ratiometric fluorescence detection of phoxim:

[0052] The PCN222(Fe)@NU-1000 solution prepared in Example 1 was diluted 10 times and 15 μL was taken;

[0053] Prepare 5×10 -6 ,5×10 -5 ,5×10 -4 ,1×10 -3 ,2×10 -3 ,3×10 -3 Take 100 μL of phoxim standard solutions of different concentrations, mix them evenly, add ultrapure water (pH=6.5) to make up the solution volume to 1 mL, and mix them evenly.

[0054] Mix 15 μL of PCN222(Fe)@NU-1000 probe solution with 985 μL of ultrapure water (pH=6.5) to form a blank sample. After 15 minutes of static reaction at room temperature, use a fluorescence spectrometer to measure the fluorescence peaks at 461±3nm and 652±3nm. The difference between the blank sample and the sample to be tested at 461±3nm and the fluorescence peak of the sample to be tested at 652±3nm are used as the ratio to construct a linear relationship. Figure 3 As shown, in the presence of phoxim, the fluorescence at 461±3nm decreased significantly, and the fluorescence peak at 652±3nm decreased slightly.

[0055] The calculated linear range of ratio fluorescence detection of phoxim was 0.005μg / mL~4μg / mL, and the detection limit was 0.004μg / mL.

[0056] Colorimetric signal detection of phoxim:

[0057] Prepare 5×10 -6 ,5×10 -5 ,5×10 -4 ,1×10 -3 ,2×10 -3 ,3×10 -3A series of concentrations of phoxim standard solution, take 50 μL of phoxim standard solution and acetylcholinesterase AchE (20 μL, 0.5U / mL) and mix at 37°C for 15 minutes. Then add ATch aqueous solution (20 μL, 12 mM) and mix at 37°C for 10 minutes. Then add 20 μL of PCN222(Fe)@NU-1000 concentrate prepared in Example 1, TMB aqueous solution (15 μL, 30 mM), H2O2 (20 μL, 2M), and 855 μL of HAc-NaAc buffer. After reacting at room temperature for 6 minutes, the absorbance at 652 nm was measured to be A. Replace phoxim with 50 μL of ultrapure water, and keep the other conditions unchanged. As a blank sample, the absorbance at 652 nm was measured to be A0. Figure 4 As shown, with the continuous increase of phoxim concentration, the absorbance value of the system gradually increases.

[0058] It was calculated that the linear range of colorimetric detection was 2.5 ng / mL to 25 ng / mL, and the detection limit was 1.76 ng / mL.

[0059] The present invention synthesizes the composite material PCN222(Fe)@NU-1000, i.e. the dual-mode sensor based on the composite metal-organic framework, by functionalizing and post-modifying the zirconium-based metal-organic framework NU-1000.

[0060] Among them, PCN222 (Fe) has both red fluorescence and peroxidase-like activity. With the help of the dual emission phenomenon of PCN222 (Fe) @ NU-1000, a ratio fluorescence method was designed through the fluorescence quenching between NU-1000 and phoxim, and a colorimetric method was designed based on the inhibitory effect of phoxim on AchE. Phoxim inhibits the generation of Ch from ATch by inhibiting the activity of AchE. Therefore, when PCN222 (Fe) @ NU-1000 catalyzes TMB to generate ox TMB, the amount of Ch reducing ox TMB decreases, the blue color of the system deepens, and the absorbance value increases. The ratio fluorescence-colorimetric dual-mode detection method based on PCN222 (Fe) @ NU-1000 constructed by the present invention, the detection results of the two modes can not only verify each other, but also greatly improve the accuracy of phoxim detection, and expand its detection linear range and detection application scenarios.

[0061] As described above, although the present invention has been shown and described with reference to specific preferred embodiments, it should not be construed as limiting the present invention itself. Various changes in form and details may be made without departing from the spirit and scope of the present invention as defined in the appended claims.

Claims

1. A method for preparing a dual-mode sensor based on a composite metal-organic framework, characterized in that: The following steps are involved: (1) dissolving zirconium oxychloride octahydrate, benzoic acid, iron (III)-tetrakis(4-carboxyphenyl)porphyrin chloride and meso-tetrakis(4-carboxyphenyl)porphine in an organic solvent, and obtaining a metal organic framework material through a solvothermal reaction; (2) centrifuging and washing the metal organic framework material obtained in step (1), and dispersing it in N,N-dimethylformamide to obtain a metal organic framework solution; (3) dissolving the metal organic framework solution obtained in step (2), benzoic acid and zirconium oxychloride octahydrate in an organic solvent, mixing them evenly, heating them for reaction, and cooling them to room temperature after the reaction is completed to obtain a solution A; (4) dissolving 1,3,6,8-tetrakis(4'-carboxyphenyl)pyrene in an organic solvent to obtain a solution B; (5) mixing solution A obtained in step (3) and solution B obtained in step (4) uniformly, adding trifluoroacetic acid, and performing a solvent thermal reaction to obtain a composite metal organic framework material; (6) Washing, centrifuging, and concentrating the composite metal organic framework material obtained in step (5) to obtain the dual-mode sensor.

2. The preparation method according to claim 1, characterized in that: In step (1), the mass ratio of zirconium oxychloride octahydrate, iron (III)-tetrakis(4-carboxyphenyl)porphyrin chloride and meso-tetrakis(4-carboxyphenyl)porphine is 60:1.1:18.7; the mass ratio of zirconium oxychloride octahydrate and benzoic acid is 3:28; and the mass volume ratio of benzoic acid and organic solvent is 28:1 mg / mL.

3. The preparation method according to claim 1, characterized in that: In step (1), the temperature of the solvent thermal reaction is 90° C.-110° C., and the reaction time is 4-6 hours.

4. The preparation method according to claim 1, characterized in that: In step (3), the volume mass ratio of the metal organic framework solution to zirconium oxychloride octahydrate is 200:43.84 μL / mg; the mass volume ratio of benzoic acid to the organic solvent is 200:1 mg / mL; the temperature of the heating reaction is 90°C-110°C, and the heating reaction time is 1-2h.

5. The preparation method according to claim 1, characterized in that: In step (4), the concentration of the 1,3,6,8-tetrakis(4'-carboxyphenyl)pyrene solution is 2.3-2.6 mg / mL.

6. The preparation method according to claim 1, characterized in that: In step (5), the volume mass ratio of trifluoroacetic acid to 1,3,6,8-tetrakis(4'-carboxyphenyl)pyrene is 2:1 μL / mg; the temperature of the solvent thermal reaction is 90° C.-110° C., and the reaction time is 4-6 h.

7. The preparation method according to claim 1, characterized in that: The organic solvent is N,N-dimethylformamide containing 1% v / v water.

8. A dual-mode sensor based on a composite metal-organic framework prepared by the preparation method according to any one of claims 1 to 7.

9. Use of the dual-mode sensor based on a composite metal organic framework according to claim 8 in detecting phoxim.

10. The use according to claim 9, characterized in that: The phoxim sample solution and the dual-mode sensor solution are mixed, the fluorescence peaks at 461±3 nm and 652±3 nm are measured, and a linear relationship is established by taking the difference between the blank sample and the sample to be tested at 461±3 nm and the fluorescence peak of the sample to be tested at 652±3 nm as a ratio; a phoxim sample solution of known concentration and acetylcholinesterase are mixed for reaction, thioacetylcholine is added for mixed reaction, the concentrated solution of the dual-mode sensor, TMB, H2O2, and HAc-NaAc buffer are added, and after the reaction, the absorbance value at 652 nm is measured, and a linear relationship is established between the measured absorbance value and the phoxim concentration.

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