Hydrogen bond organic framework composite material and preparation method and application thereof

Abstract

The invention relates to the technical field of sensors, in particular to a hydrogen bond organic framework composite material and a preparation method and application thereof. The specific technical scheme is as follows: the preparation method of the hydrogen bond organic framework composite material comprises the following steps: dissolving 1, 3, 6, 8-tetra (4-carboxybenzene) pyrene in N, N-dimethylformamide under ultrasound, then slowly adding methanol mixed with a PEDOT: PSS aqueous dispersion, stirring and reacting at normal temperature, and after the reaction is completed, centrifuging to obtain the HHOF-101 / PEDOT: PSS composite material. The biosensor constructed by the invention obtains remarkable and stable ECL strength and sensitive response to OPs in a PBS solution, and opens up a new way for application and development of a high-conductivity HOFs nano-material in organophosphorus detection.

Description

Technical Field

[0001] The present invention relates to the field of sensor technology, and in particular to a hydrogen bond organic framework composite material and a preparation method and application thereof. Background Art

[0002] Faced with the growing global food demand driven by population growth, organophosphorus pesticides (OPs) are ubiquitous in agriculture, especially in fruit, vegetable, and tea cultivation, due to their low cost and high effectiveness. While these pesticides have significantly improved crop yields and quality, their overuse due to unrestricted use has caused a pressing problem: the accumulation of toxic residues in water, soil, and food chains. These residues not only have harmful effects on aquatic environments, food, and crop products, but also affect soil and public health, as their residues can cause serious harm to humans when absorbed through inhalation or skin. Taking malathion as an example, the maximum residue limit is often exceeded in the environment, posing a serious threat to human health through respiratory distress, heart irregularities, and damage to vital organs such as the liver and kidneys. In addition, the irreversible inhibition of acetylcholinesterase (AChE) activity by OPs exacerbates their toxicity. In view of this negative situation, it is crucial to develop efficient and sustainable techniques to accurately identify and quantify OPs residues in environmental and food matrices.

[0003] At present, although traditional methods for detecting OPs, such as colorimetry, high performance liquid chromatography, gas chromatography-mass spectrometry (GC-MS), fluorescence and electrochemical methods, are widely used, these methods are still limited by low sensitivity, high solvent consumption, high technical requirements, lengthy pre-treatment time and expensive instruments. Therefore, innovative approaches are urgently needed to overcome these obstacles and ensure reliable monitoring of OPs residues to protect the environment and public health. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention provides a hydrogen-bonded organic framework composite material and a preparation method and application thereof.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solutions:

[0006] The invention discloses a method for preparing a hydrogen-bonded organic framework composite material. Under ultrasound, 1,3,6,8-tetrakis(4-carboxyphenyl)pyrene is dissolved in N,N-dimethylformamide, and then methanol mixed with a PEDOT:PSS aqueous dispersion is slowly added and stirred to react at room temperature. After the reaction is completed, the HOF-101 / PEDOT:PSS composite material is obtained by centrifugation.

[0007] Preferably, the mass percentage of the PEDOT:PSS aqueous dispersion is 1.5wt%, the volume ratio of the PEDOT:PSS aqueous dispersion to methanol is 1-5:44-40, and the total volume of the mixture of the PEDOT:PSS aqueous dispersion and methanol remains unchanged.

[0008] Preferably, the usage ratio of 1,3,6,8-tetrakis(4-carboxyphenyl)pyrene to N,N-dimethylformamide is 5 to 7:1, m / v.

[0009] Correspondingly, a hydrogen-bonded organic framework composite material prepared by the above preparation method.

[0010] Correspondingly, a biosensor comprises the hydrogen-bonded organic framework composite material prepared by the above preparation method.

[0011] Correspondingly, a method for preparing a biosensor is to drop a Nafion solution and a HOF-101 / PEDOT:PSS composite material on the surface of a glassy carbon electrode in sequence and dry them under infrared light to obtain HOF-101 / PEDOT:PSS / GCE; then drop an AChE solution again to obtain AChE / HOF-101 / PEDOT:PSS / GCE.

[0012] Preferably, the volume ratio of the Nafion solution to the HOF-101 / PEDOT:PSS composite material is 1:1, the concentration of the HOF-101 / PEDOT:PSS composite material is 0.02-1.2 mg / mL, the mass fraction of the Nafion solution is 0.5%, and the concentration of AChE is 0.01-0.05 U / L.

[0013] Correspondingly, the biosensor prepared by the above preparation method is used in the detection of malathion.

[0014] Preferably, the biosensor is incubated in OPs solutions of different concentrations at 37° C. for 15 min, and then transferred to an electrochemical detection cell for detection. The electrochemical detection cell uses the biosensor as a working electrode, a platinum wire as a counter electrode, and an Ag / AgCl electrode as a reference electrode. The electrochemical detection cell includes K prepared by PBS solution. 2 S 2 O 8 and ATCl mixed solution, the solution pH value is 6 to 11, the K 2 S 2 O 8 The concentration of is 0.005-0.025 mol / L, and the concentration of ATCl is 2-7 mmol / L.

[0015] Preferably, during the detection process, the scanning rate is 100 mV / s and the potential scanning range is 0 to -2.0 V.

[0016] The present invention has the following beneficial effects:

[0017] Compared with traditional technologies, electrochemiluminescence (ECL) is a technology that combines the advantages of electrochemistry and chemiluminescence to convert electrochemical energy into light energy. It has attracted great attention from researchers due to its faster detection speed, higher sensitivity, lower background signal and lower cost. In the present invention, ECL technology is used to cleverly combine poly (3,4-ethylenedioxythiophene): polystyrene sulfonate (PEDOT: PSS) with hydrogen-bonded organic framework materials (HOFs). Since HOF-101 / PEDOT: PSS has excellent ECL properties, it is used as a new type of ECL emitter to successfully develop an ECL biosensor for ultra-sensitive detection using AChE modification. By controlling key factors such as the ratio of composite materials, material concentration, and coreactant concentration, a new electrochemiluminescence detection system is constructed. At present, the constructed sensor has obtained significant and stable ECL intensity, as well as a sensitive response to OPs in PBS solution, which has opened up a new path for the application and development of high-conductivity HOFs nanomaterials in organic phosphorus detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 (A) shows the preparation of HOF-101 / PEDOT:PSS; (B) shows the fabrication of ECL biosensor; (C) shows the preparation of HOF-101 / PEDOT:PSS-K 2 S 2 O 8 Schematic diagram of ECL analysis;

[0019] Figure 2 This is the optimization diagram of the amount of PEDOT:PSS added in the synthesis of HOF-101 / PEDOT:PSS;

[0020] Figure 3 Optimization diagram for HOF-101 / PEDOT:PSS concentration;

[0021] Figure 4 K is the co-reactant 2 S 2 O 8 Concentration optimization diagram of

[0022] Figure 5 This is the concentration optimization diagram of AChE;

[0023] Figure 6 is the concentration optimization diagram of ATCl;

[0024] Figure 7 is the optimization diagram of reaction pH;

[0025] Figure 8 is the ECL signal intensity under different conditions;

[0026] Fig. 9 (A) shows the ECL response of the biosensor to different concentrations of malathion, where: (a) 3.0×10 -13 M, (b) 3.0×10 -12 M, (c) 3.0×10 -11 M, (d) 3.0×10 -10 M, (e) 3.0×10 -9 M, (f) 3.0×10 -8 M, (g) 3.0×10 -7 M; (B) is the standard curve of ECL intensity changing with the logarithm of malathion concentration;

[0027] Fig.10 The stability of the ECL biosensor in the presence of 0.1 pM and 100 pM malathion was continuously scanned for 10 cycles.

[0028] Fig.11 When the malathion concentration is 3.0×10 -13 M, the reproducibility of the constructed ECL biosensor;

[0029] Fig.12 For specificity experiments with the addition of malathion and various interfering substances;

[0030] Fig.13 To compare the ECL intensity when no pesticide was added (blank) and when different pesticides were added. DETAILED DESCRIPTION

[0031] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] Unless otherwise specified, the technical means used in the embodiments are conventional means well known to those skilled in the art.

[0033] The invention discloses a method for preparing a hydrogen-bonded organic framework composite material. Under ultrasound, 1,3,6,8-tetrakis(4-carboxyphenyl)pyrene is dissolved in N,N-dimethylformamide, and then methanol mixed with a PEDOT:PSS aqueous dispersion is slowly added, and the mixture is stirred and reacted at room temperature. After the reaction is completed, the HOF-101 / PEDOT:PSS composite material is obtained by centrifugation.

[0034] The mass percentage of the PEDOT:PSS aqueous dispersion is 1.5wt%, the volume ratio of the PEDOT:PSS aqueous dispersion to methanol is 1-5:44-40, and the total volume of the mixture of the PEDOT:PSS aqueous dispersion and methanol remains unchanged. The amount ratio of the 1,3,6,8-tetrakis(4-carboxyphenyl)pyrene to N,N-dimethylformamide is 5-7:1, m / v.

[0035] The present invention also discloses a biosensor, comprising the hydrogen-bonded organic framework composite material prepared by the above preparation method. The preparation process of the biosensor is: dripping Nafion solution and HOF-101 / PEDOT:PSS composite material on the surface of glassy carbon electrode in sequence, and drying under infrared light to obtain HOF-101 / PEDOT:PSS / GCE; then dripping AChE solution again to obtain AChE / HOF-101 / PEDOT:PSS / GCE.

[0036] The volume ratio of the Nafion solution to the HOF-101 / PEDOT:PSS composite material is 1:1, the concentration of the HOF-101 / PEDOT:PSS composite material is 0.02-1.2 mg / mL, the mass fraction of the Nafion solution is 0.5%, and the concentration of AChE is 0.01-0.05 U / L.

[0037] The invention also discloses the application of the biosensor prepared by the preparation method in detecting malathion.

[0038] Specifically, the biosensor was incubated in OPs solutions of different concentrations at 37°C for 15 min, and then transferred to an electrochemical detection cell for detection. The electrochemical detection cell used the biosensor as a working electrode, a platinum wire as a counter electrode, and an Ag / AgCl electrode as a reference electrode. The electrochemical detection cell included K prepared by PBS solution. 2 S 2 O 8 and ATCl mixed solution, the solution pH value is 6 to 11, the K 2 S 2 O 8 The concentration of is 0.005-0.025 mol / L, and the concentration of ATCl is 2-7 mmol / L.

[0039] Preferably, during the detection process, the scanning rate is 100 mV / s, the potential scanning range is 0 to -2.0 V, and the photomultiplier tube (PMT) voltage is set to 1000 V during the detection process.

[0040] The present invention will be further described below in conjunction with specific embodiments.

[0041] The buffer used in the following examples is as follows:

[0042] (1) Solvent buffer for AChE solution: Tris-HCl buffer, 10 mM Tris-HCl, 1.0 mM ethylenediaminetetraacetic acid (EDTA), pH adjusted to 8.0.

[0043] (2) ATCl solution solvent buffer: PBS buffer, 1M Na 2 HPO 4 , 0.1M KH 2 PO 4 , 0.1 M NaCl and 0.1 M KCl, and the pH was adjusted to 10.0.

[0044] (3) Detection buffer solution: PBS buffer, 1M Na 2 HPO 4 , 0.1M KH 2 PO 4 , 0.1 M NaCl and 0.1 M KCl, and the pH was adjusted to 10.0.

[0045] Example 1

[0046] 1. Synthesis of HOF-101

[0047] 1,3,6,8-tetrakis(4-carboxyphenyl)pyrene (H 4 TBAPy (75 mg, 0.11 mol) was dissolved in N,N-dimethylformamide (DMF, 11.25 mL). Then, methanol (CH 3 OH) (45 mL) and stirred for 30 min. Finally, the mixed solution was kept at ambient temperature for 12 h, and a yellow powder was obtained by centrifugation. 3 OH and acetone for 3 times.

[0048] 2. Synthesis of HOF-101 / PEDOT:PSS

[0049] exist Figure 1(A) describes the synthesis process of HOF-101 / PEDOT:PSS. The synthesis of HOF-101 / PEDOT:PSS is as follows: During the synthesis of HOF-101, a certain volume of PEDOT:PSS (1.5 wt%) aqueous dispersion is added to CH 3 OH, and at the same time, the aqueous dispersion of PEDOT:PSS and CH 3 The total volume of the mixture of OH was always 45 ml. Then, the same method was used to prepare.

[0050] For comparison, the volume of the aqueous dispersion of PEDOT:PSS was changed (1 mL, 2 mL, 3 mL, 4 mL, 5 mL) to prepare HOF-101 / PEDOT:PSS composites with different PEDOT:PSS contents.

[0051] 3. Preparation of Biosensor

[0052] Figure 1 (B) is the preparation process of the biosensor, the specific process is: the bare GCE is polished with alumina slurry. The electrode is ultrasonically cleaned in distilled water and ethanol respectively, and dried at room temperature. Then, 5μL of Nafion solution (0.5%) and 5μL of HOF-101 / PEDOT:PSS composite material mixed solution are dropped on the GCE surface in sequence and dried under infrared light to obtain HOF-101 / PEDOT:PSS / GCE. Finally, 3μL of AChE solution is dropped on the electrode to obtain AChE / HOF-101 / PEDOT:PSS / GCE. The biosensor is stored at 4°C for subsequent use. After step-by-step assembly, the electrode must be rinsed with ultrapure water.

[0053] 4. ECL detection

[0054] Figure 1 (C) HOF-101 / PEDOT:PSS-K 2 S 2 O 8 Schematic diagram of ECL analysis. The electrochemiluminescence detection system is a classic three-electrode system, as follows: a modified glassy carbon electrode (AChE / HOF-101 / PEDOT:PSS / GCE, Φ=3 mm) as the working electrode, a platinum wire as the counter electrode, and an Ag / AgCl electrode (saturated potassium chloride) as the reference electrode.

[0055] The biosensor was incubated in OPs solutions of different concentrations at 37°C for 15 min. The biosensor was then transferred to an electrochemical detection cell with a volume of 10 mL, which contained a total volume of 5 mL of PBS solution (0.1 M, pH = 10.0) containing 0.02 M K2 S 2 O 8 and 6 mM ATCl mixed solution. The ECL detection parameters are scanning rate 100 mV / s, potential scanning range 0~-2.0 V. During the detection process, the photomultiplier tube (PMT) voltage is set to 1000 V.

[0056] Example 2 Study on Detection of Malathion Based on Electrochemiluminescence

[0057] 1. Optimization of PEDOT:PSS addition amount in HOF-101 / PEDOT:PSS synthesis

[0058] The volume of the aqueous dispersion of PEDOT:PSS (1.5 wt % in water) was changed (1 mL, 2 mL, 3 mL, 4 mL, 5 mL) to prepare HOF-101 / PEDOT:PSS composites with different PEDOT:PSS contents. The ECL response of the sensor modified with the same concentration solution (ethanol-water solution) prepared from the HOF-101 / PEDOT:PSS composites synthesized with different volumes of PEDOT:PSS dispersions, such as Figure 2 As shown in Figure 3, the ECL signal of the HOF-101 / PEDOT:PSS composite gradually increased with the initial increase in the volume of the PEDOT:PSS dispersion. However, when the volume exceeded 3 mL, the ECL signal decreased.

[0059] 2. Optimization of HOF-101 / PEDOT:PSS concentration

[0060] like Figure 3 As shown in Figure 2, with the increase of HOF-101 / PEDOT:PSS concentration, the ECL intensity first increases and then decreases. This is because a higher HOF-101 / PEDOT:PSS concentration will hinder electron transfer.

[0061] 3. Co-reactant K 2 S 2 O 8 Optimization of concentration

[0062] With S 2 O 8 2- With the increase of concentration, the ECL signal gradually increases, such as Figure 4 However, when the concentration is greater than 0.02 mol / L, the ECL signal of the system reaches a plateau state.

[0063] 4. Optimization of AChE concentration

[0064] Under optimized conditions, such as Figure 5As shown in the figure, when the AChE concentration reaches 0.02U / L, the ECL signal value is the largest. When the AChE concentration continues to increase, the ECL signal decreases. This indicates that the blocking effect of AChE is enhanced.

[0065] 5. Optimization of ATCl concentration

[0066] Optimize the concentration of ATCl in the ECL detection solution, such as Figure 6 As shown in Figure 2, when the ATCI concentration increased from 2.0mmol / L to 6.0mmol / L, the ECL signal increased significantly and then began to decrease. This was because the active center of the AChE enzyme was almost occupied by ATCl. Therefore, 6.0mmol / L was selected as the optimal ATCI concentration for subsequent studies.

[0067] 6. Optimization of reaction pH

[0068] The ECL signal of this biosensor also depends on K 2 S 2 O 8 The invention is carried out in the pH range of 6.00 to 11.00. Figure 7 It was shown that the ECL signal gradually increased with the increase of pH from 6.00 to 10.00 and then gradually decreased from 10.00 to 11.00, which was due to the inhibition of acetylcholinesterase activity under high pH conditions.

[0069] Example 3 Biosensor Performance

[0070] 1. ECL signal strength under different conditions

[0071] In this ECL sensing platform, HOF-101 was used as the signal probe, and K 2 S 2 O 8 As a co-reactant. Figure 8 (A) and Figure 8 In (B), for the bare GCE, it is clear that the ECL intensity is very weak (curve a). Then, the ECL signal generated by HOF-101 increases (curve b). It should be noted that when the polymer PEDOT:PSS is introduced, PEDOT:PSS is combined with HOF-101 through hydrogen bonding to form HOF-101 / PEDOT:PSS, and the ECL signal is enhanced.

[0072] When HOF-101 / PEDOT:PSS was modified on GCE, the ECL emission intensity of HOF-101 / PEDOT:PSS (curve c) was 2.03 times higher than that of HOF-101, which proved that PEDOT:PSS could catalyze the decomposition of K 2 S2 O 8 The co-reaction acceleration and higher conductivity improve the electrochemical excitation of HOF-101 luminophore. When acetylcholinesterase was applied (curve d), the ECL signal dropped from 32,890 to 23,623, which indicates that the biomacromolecules hindered the transfer of electrons.

[0073] In addition, the effects of ATCl on the proposed AChE / HOF-101 / PEDOT:PSS / Nafion / GCE-K 2 S 2 O 8 The quenching effect of the ECL signal of the luminescent system (curve e). Acetylcholinesterase hydrolyzes ATCl to generate thiocholine. Part K 2 S 2 O 8 The reaction with choline sulfate formed sulfate, resulting in a decrease in the ECL reaction of HOF-101 / PEDOT:PSS. When the detector malathion was introduced into the ECL system (curve f), malathion inhibited the activity of acetylcholinesterase, resulting in a decrease in the production of choline sulfate. Therefore, the addition of malathion to the ECL platform can significantly restore the quenched signal of HOF-101 / PEDOT:PSS, which means that the proposed AChE / HOF-101 / PEDOT:PSS / Nafion / GCE-K 2 S 2 O 8 The system's ECL biosensor can be used for malathion analysis.

[0074] 2. Sensitivity of ECL biosensor

[0075] Using malathion as a model, the biosensor AChE / HOF-101 / PEDOT:PSS / Nafion / GCE was studied for the effect of K 2 S 2 O 8 ECL responses of OPs in PBS with ATCl and PBS. Under the optimal experimental conditions, the responses of the ECL biosensor to different concentrations of malathion were recorded. Fig. 9 As shown in (A), the intensity of ECL gradually increased with the increase of malathion concentration, covering a concentration range from 3.0×10 -13 ~3.0×10 -7 M (in the figure: (a) 3.0×10 -13 M, (b) 3.0×10 -12 M, (c) 3.0×10 -11 M, (d) 3.0×10 -10 M, (e) 3.0×10 -9M, (f) 3.0×10 -8 M, (g) 3.0×10 -7 M) from Fig. 9 (B) It can be seen that the ECL response value is linearly related to the logarithm of the malathion concentration (lgc). The corresponding calibration curve equation is I = 2803.9lgc + 38253.4, and the correlation coefficient R 2 The estimated detection limit (LOD) was 9.1×10 -14 M(S / N=3).

[0076] 3. Stability of ECL biosensor

[0077] To investigate its stability, the fluctuation of ECL intensity was analyzed after 10 cycles of continuous scanning at two concentrations of 0.1 pM and 100 pM malathion. Fig.10 It can be seen that the variation of ECL intensity is small, and the relative standard deviations (RSDs) are 0.91 and 1.35%, respectively, indicating that the stability of the prepared ECL biosensor is acceptable.

[0078] 4. Reproducibility of ECL biosensor

[0079] exist Fig.11 In the experiment, the same concentration of malathion (3.0×10 -13 M) were measured three times in parallel (same batch refers to the comparison of multiple samples in the same batch, and different batches refer to the comparison of samples between different experimental batches). The results showed that the RSD of the peak signal between batches was 4.92%, and the RSD of the peak signal within the batch was 1.53%, indicating that the biosensor has good reproducibility.

[0080] 5. Specificity of ECL biosensor

[0081] In order to evaluate the specificity of the ECL sensor, cypermethrin, chlorothalonil, indoxacarb, cypermethrin, and procymidone were used as interfering substances because they are common pesticides in food samples and may coexist with malathion. Fig.12 (In the figure: blank sample, concentration is 3.0×10 -13 Malathion, 3.0×10 -7 M of highly effective cypermethrin, chlorothalonil, indoxacarb, cypermethrin, procymidone and pesticide residue mixture (3.0×10 -7 M of cypermethrin, thiophanate-methyl, indoxacarb, cypermethrin, procymidone and 3.0×10 -13M of malathion)), the ECL intensity produced by the addition of these interfering substances did not change significantly compared with the blank sample (the blank was an equal volume of PBS solution without interfering substances). At the same time, 3.0×10 -7 The ECL signal generated by malathion was comparable to that generated by the addition of 3.0×10 -7 The ECL signals generated by M malathion were the same, indicating that the ECL sensor has good anti-interference ability for malathion detection and is also suitable for the detection of malathion in complex environments.

[0082] 6. Universality of ECL biosensors for detecting organophosphorus pesticides

[0083] Due to the irreversible inhibition of acetylcholinesterase activity by OPs, the proposed sensing strategy should also be effective for the detection of other OPs. Therefore, several common OPs (i.e., trichlorfon, diazinon, profenofos, chlorpyrifos, and triazophos) were used as models. Fig.13 (In the figure: blank sample, concentration is 3.0×10 -11 M of malathion, trichlorfon, diazinon, profenofos, chlorpyrifos, triazophos and pesticide residue mixture (3.0×10 -11 M of malathion, trichlorfon, diazinon, profenofos, chlorpyrifos and triazophos)) as shown in the figure. The same concentration of trichlorofluoride, chlorpyrifos and triazophos (3.0×10 -11 M) and malathion (3.0×10 -11 M) produced similar ECL signals compared with the blank sample without any pesticide added, while diazinon and profenofos produced similar ECL signals with the same concentration (3.0×10 -11 However, the ECL signals of these OPs were significantly increased, indicating the universality of this ECL sensor for OPs detection.

[0084] Example 4

[0085] 1. Sample Pretreatment

[0086] In order to test whether the biosensor can be used to detect the OPs content in actual vegetables, Chinese cabbage and lettuce were selected as experimental objects, and all vegetables were purchased from local supermarkets. First, wash the vegetables with ultrapure water and dry them. Cut the vegetables into small pieces with a knife, put 0.4g of small pieces of vegetables into a centrifuge tube, and then add a certain concentration of malathion standard to the vegetables in the centrifuge tube and place them at 37℃ for 24h. Add 1mL acetone, 9mL 0.01M PBS (pH=10.0), ultrasonicate for 20min, centrifuge at 10000rpm for 15min, take the supernatant for determination, perform a standard recovery experiment, and record the changes in ECL intensity.

[0087] The spinach powder used in the quality control sample experiment was pre-treated according to the national standard GB 23200.8-2016.

[0088] 2. Sample determination and recovery calculation

[0089] In order to further verify the practicality and reliability of the ECL sensing platform for detecting real samples, the supernatants of two vegetables were mixed with 0.02 MK 2 S 2 O 8 PBS solution (pH 10.0) were mixed evenly and the ratio was 1:4, and then different concentrations of malathion standard samples (3.0×10 -13 , 3.0×10 -11 and 3.0×10 -7 ) was used for ECL detection. Table 1 shows the detection results of the biosensor. The recoveries of malathion in the two vegetable samples ranged from 99.3 to 107.1%, with an RSD of less than 4.89%.

[0090] Table 1 Recovery of malathion added to different samples (n=3)

[0091] sample Addition amount (M) Detection amount (M) Recovery rate (%) RSD(%) Cabbage 1 <![CDATA[3.0×10 -13 ]]> <![CDATA[3.2×10 -13 ]]> 107.1 1.77 Cabbage 2 <![CDATA[3.0×10 -10 ]]> <![CDATA[3.0×10 -10 ]]> 99.3 4.33 Cabbage 3 <![CDATA[3.0×10 -7 ]]> <![CDATA[3.1×10 -7 ]]> 101.8 2.08 Lettuce 1 <![CDATA[3.0×10 -13 ]]> <![CDATA[3.1×10 -13 ]]> 103.8 4.89 Lettuce 2 <![CDATA[3.0×10 -10 ]]> <![CDATA[3.1×10 -10 ]]> 102.2 4.45 Lettuce 3 <![CDATA[3.0×10 -7 ]]> <![CDATA[3.1×10 -7 ]]> 101.7 3.89

[0092] The spinach quality control sample was then selected as the next test sample. The preparation procedure for the sample test solution was the same as for the two vegetable samples mentioned above. As can be seen from Table 2, the results of the spinach powder test showed a recovery rate (98.4-100.7%) and an RSD (4.51-6.75%). In addition, the spinach quality control sample was again tested for recovery using the standard addition method. The results of the spinach quality control sample (Table 3) also showed a considerable recovery rate (94.8-99.7%) and an RSD (1.38-3.41%), indicating that the method is stable and reliable.

[0093] These results indicate that the proposed sensing platform is feasible for malathion detection and analysis in complex real samples and has potential practical application value.

[0094] Table 2 Recovery of malathion in spinach quality control samples (n=3)

[0095] sample Concentration(M) Detection amount (M) Recovery rate (%) RSD(%) Spinach 1 <![CDATA[4.0×10 -12 ]]> <![CDATA[4.05×10 -12 ]]> 98.4 4.51 Spinach 2 <![CDATA[4.0×10 -11 ]]> <![CDATA[4.02×10 -11 ]]> 100.7 6.75

[0096] Table 3 Recovery of malathion added to spinach quality control samples (n=3)

[0097]

[0098]

[0099] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A method for preparing a hydrogen-bonded organic framework composite material, characterized in that: Under ultrasound, 1,3,6,8-tetrakis(4-carboxyphenyl)pyrene was dissolved in N,N-dimethylformamide, and then methanol mixed with PEDOT:PSS aqueous dispersion was slowly added and stirred to react at room temperature. After the reaction was completed, the HOF-101 / PEDOT:PSS composite material was obtained by centrifugation.

2. The preparation method according to claim 1, characterized in that: The mass percentage of the PEDOT:PSS aqueous dispersion is 1.5wt%, the volume ratio of the PEDOT:PSS aqueous dispersion to methanol is 1-5:44-40, and the total volume of the mixture of the PEDOT:PSS aqueous dispersion and methanol remains unchanged.

3. The preparation method according to claim 1, characterized in that: The usage ratio of 1,3,6,8-tetrakis(4-carboxyphenyl)pyrene to N,N-dimethylformamide is 5-7:1, m / v.

4. A hydrogen-bonded organic framework composite material prepared by the preparation method according to any one of claims 1 to 3.

5. A biosensor, characterized in that: The invention comprises a hydrogen-bonded organic framework composite material prepared by the preparation method according to any one of claims 1 to 3.

6. A method for preparing the biosensor according to claim 5, characterized in that: Nafion solution and HOF-101 / PEDOT:PSS composite material were sequentially dropped onto the surface of glassy carbon electrode and dried under infrared light to obtain HOF-101 / PEDOT:PSS / GCE; then AChE solution was dropped again to obtain AChE / HOF-101 / PEDOT:PSS / GCE.

7. The preparation method according to claim 6, characterized in that: The volume ratio of the Nafion solution to the HOF-101 / PEDOT:PSS composite material is 1:1, the concentration of the HOF-101 / PEDOT:PSS composite material is 0.02-1.2 mg / mL, the mass fraction of the Nafion solution is 0.5%, and the concentration of the AChE is 0.01-0.05 U / L.

8. Use of the biosensor prepared according to the preparation method of claim 6 or 7 in detecting malathion.

9. The use according to claim 8, characterized in that: The biosensor was incubated in OPs solutions of different concentrations at 37° C. for 15 min, and then transferred to an electrochemical detection cell for detection. The electrochemical detection cell used the biosensor as a working electrode, a platinum wire as a counter electrode, and an Ag / AgCl electrode as a reference electrode. The electrochemical detection cell included a mixed solution of K2S2O8 and ATCl prepared by a PBS solution, the pH value of the solution was 6 to 11, the concentration of the K2S2O8 was 0.005 to 0.025 mol / L, and the concentration of the ATCl was 2 to 7 mmol / L.

10. The use according to claim 9, characterized in that: During the detection process, the scanning rate was 100 mV / s and the potential scanning range was 0 to -2.0 V.

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