A preparation method of a magnetic MOF composite material and a detection method for chemicals thereof

Abstract

The present invention relates to the field of compound detection technology, and discloses a preparation method of a magnetic MOF composite material and a detection method for chemicals. The magnetic MOF composite material is a core-shell structure, including a magnetic core, an outer metal organic framework structure, and the metal organic framework structure has 2 to 5 nm pores on the surface. The pores contain one or more of carboxyl groups, aromatic groups, hydrophobic bonds, π-π bonds, salt bonds, and hydrogen bond binding sites, and are used to adsorb psychiatric drugs in serum. The adsorption recovery rate is 94% to 113%, and the protein exclusion rate exceeds 95%. The present invention has the advantages of rapid magnetic separation, efficient adsorption of psychiatric drugs in serum, and a high protein exclusion rate, which can simplify the detection process and reduce the detection error caused by protein interference.

Description

Technical Field

[0001] The present invention relates to the technical field of compound detection, and in particular to a preparation method of a magnetic MOF composite material and a detection method for chemicals using the same. Background Art

[0002] Psychotropic medications provide effective treatment for various mental illnesses. However, the type of medication, dosage, and individual patient differences can lead to numerous side effects in patients taking these medications. Therefore, blood drug concentration monitoring is recommended in clinical psychiatric medication treatment to avoid medical complications, poisoning, non-response, or non-compliance. Therefore, enhanced blood drug concentration monitoring is essential for the treatment of psychotropic medications.

[0003] Blood drug concentration monitoring involves quantitatively analyzing the concentrations of drugs and their metabolites in biological samples using various modern analytical and quantitative methods. This is used to study the safe concentration range of drugs in the human body and utilize pharmacokinetic methods to calculate optimal drug dosages and dosing intervals, thereby achieving the goal of precision medicine. Human serum contains high levels of protein, and the concentrations of psychiatric drugs in human blood are generally low. Furthermore, patients often take other medications together, which can significantly interfere with drug analysis and monitoring. Therefore, serum sample pretreatment methods must be highly selective and sensitive to ensure accurate qualitative and quantitative analysis. Commonly used pretreatment methods for enriching psychiatric drugs in serum include solid-phase extraction (SPE), liquid-liquid extraction (LLE), and protein precipitation (PP). Currently, these traditional methods generally require the addition of a certain amount of organic reagent to precipitate proteins in the serum to prevent clogging of the analytical instrument pipelines, resulting in lengthy extraction times and cumbersome procedures. However, the porous structure of MOF materials effectively eliminates protein adsorption and exhibits high adsorption efficiency for specific drugs. Magnetic MOF materials can also facilitate rapid separation from the test sample, simplifying the detection process.

[0004] China's existing patent 201610633419.X discloses a method for adsorbing nicotine in tobacco leaves using magnetic nanospheres, which has the following advantages: (1) the strong magnetism of the magnetic microspheres is utilized to facilitate and quickly separate them from the mixture; (2) the mesoporous SiO2 enhances the adsorption area of the magnetic material and can effectively combine with the carbon chain in N-propylethylenediamine; (3) N-propylethylenediamine can enhance the monodispersity of the magnetic microspheres in the solution / solvent and strengthen the adsorption of polar organic matter; (4) the outermost Zr-MOF can form π-π and p-π bonds with the heterocycles in nicotine to achieve a good adsorption effect; however, there is no mention of how to prepare magnetic MOF materials that can efficiently adsorb psychiatric drugs. Summary of the Invention

[0005] Since there is no technology in the prior art for producing magnetic MOF materials that can efficiently adsorb psychiatric drugs, the present invention provides a magnetic MOF composite material, which has the advantages of being able to undergo rapid magnetic separation, efficiently adsorb psychiatric drugs in serum, and have a high exclusion rate for proteins. The present invention also provides a method for preparing the magnetic MOF composite material, and the prepared magnetic MOF composite material has the advantages of being able to undergo rapid magnetic separation, efficiently adsorb psychiatric drugs in serum, and have a high exclusion rate for proteins. The present invention also provides a detection method using the magnetic MOF composite material, which has the advantages of being able to undergo rapid magnetic separation, efficiently adsorb psychiatric drugs in serum, and have a high exclusion rate for proteins, can simplify the detection process, and reduce detection errors caused by protein interference.

[0006] The present invention is achieved by the following technical solutions:

[0007] A magnetic MOF composite material for detecting psychotic drugs in serum. The magnetic MOF composite material has a core-shell structure, including a magnetic core wrapped with a metal-organic framework structure. The surface of the metal-organic framework structure has 2-5 nm pores. The pores contain one or more of carboxyl groups, aromatic groups, hydrophobic bonds, π-π bonds, salt bonds and hydrogen bond binding sites. The magnetic MOF composite material is used for adsorbing psychotic drugs in serum, with an adsorption recovery rate of 94% to 113% and a protein exclusion rate of over 95%.

[0008] The 2-5 nm pores can effectively exclude the adsorption of proteins. The various groups contained in the pores are conducive to forming multiple connections with various psychiatric drugs, which provides the structural basis for the efficient adsorption of drugs in serum. The magnetic core makes the magnetic MOF composite material magnetically oriented and can sensitively respond to the external magnetic field. The magnetic core with no adsorption force is wrapped inside the magnetic MOF composite material to form a uniform core-shell structure, maintaining a large specific surface area and efficient adsorption capacity.

[0009] Preferably, the magnetic MOF composite material further has a silicon-based layer embedded between the magnetic core and the metal-organic framework structure; the magnetic core is Fe3O4, the silicon-based layer is SiO2, and the metal-organic framework structure is Zr-MOF; the presence of the silicon-based layer is to prevent Fe3O4 from losing its magnetism due to oxidation, thereby effectively extending the magnetic life of the magnetic MOF composite material.

[0010] A method for preparing a magnetic MOF composite material for psychiatric drugs in serum, characterized by comprising the following steps:

[0011] 1) Ferric chloride hexahydrate and anhydrous sodium acetate are uniformly stirred in an ethylene glycol solution, and then transferred to a reactor for reaction to obtain a black suspension, which is washed and dried to obtain Fe3O4; 2) The Fe3O4 prepared in step 1) is immersed in dilute hydrochloric acid, washed, and then dispersed in a mixed solution of water, ethanol, and ammonia, and ultrasonicated, and ethyl orthosilicate is added and stirred, and the product is magnetically separated, washed, and dried to obtain Fe3O4@SiO2;

[0012] 3) The Fe3O4@SiO2, ZrCl4, and biphenyl-4,4'-dicarboxylic acid synthesized in step 2) were dissolved in DMF and ultrasonically stirred, and then transferred into a reactor for reaction. After the reaction was completed, the Fe3O4@SiO2@Zr-MOF was obtained by washing and drying.

[0013] Preferably, the mass ratio of ferric chloride hexahydrate, anhydrous sodium acetate and ethylene glycol in step 1) is 1:2-3:1:90-110, the temperature in the reactor is 190-210° C., and the reaction time is 7-9 h.

[0014] Preferably, the concentration of the dilute hydrochloric acid in step 2) is 0.9-1.1 mol / L, the immersion time is 9-11 h, the mass ratio of Fe3O4, dilute hydrochloric acid, ultrapure water, ethanol, ammonia water and tetraethyl orthosilicate is 1:190-210:70-90:4-6:4-6:1, the ultrasonic time is 20-40 min, and the stirring time after ultrasonication is 11-13 h.

[0015] Preferably, in step 3), the ultrasonic time is 20 to 40 minutes, the stirring time after ultrasonication is 3 to 5 hours, the reactor temperature is 130 to 150°C, the stirring time is 17 to 19 hours, and the mass ratio of Fe3O4@SiO2, zirconium tetrachloride, biphenyl-4,4'-dicarboxylic acid and DMF is 1:2-3:2-3:400-600.

[0016] Fine-tuning the above experimental parameters is conducive to the uniform wrapping of Zr-MOF on the outer surface of the magnetic core to form a uniform spherical shape. The surface of the spherical magnetic MOF composite material contains a large number of carboxyl groups, aromatic groups, hydrogen bonding sites, hydrophobic bonds, π-π bonds, and salt bonds, maintaining a huge adsorption area and efficient adsorption capacity for psychiatric drugs.

[0017] Preferably, the prepared product is Fe3O4@SiO2@UiO-67, and the adsorbed psychiatric drug is one of risperidone, quetiapine, aripiprazole, clozapine and its metabolites 9-hydroxyrisperidone, N-desalkylated quetiapine, and dehydroaripiprazole.

[0018] A detection method for detecting drugs in serum using a magnetic MOF composite material for psychiatric drugs in serum or a magnetic MOF composite material prepared by the above-mentioned preparation method, comprising adding the magnetic MOF composite material to a serum sample to be tested to eliminate protein adhesion and adsorb and enrich psychiatric therapeutic drugs, then magnetically separating the magnetic MOF composite material, mixing the magnetic MOF composite material with an eluent, fully eluting and magnetically separating to obtain a supernatant, blowing the supernatant to dryness, then adding a re-solution for re-dissolution, and preparing a detection sample for detection by chromatography-mass spectrometry.

[0019] Preferably, the method specifically includes the following steps:

[0020] S1. Place Fe3O4@SiO2@UiO-67 in a 96-well plate solid phase extraction instrument, add serum sample and buffer to the 96-well plate, shake to disperse the Fe3O4@SiO2@UiO-67, magnetically separate the Fe3O4@SiO2@UiO-67, and discard the supernatant; the volume ratio of the buffer to serum is 19:1;

[0021] S2. Add the elution solution to the Fe3O4@SiO2@UiO-67 in step 1), shake, fully elute and then perform magnetic separation, add the supernatant to a new 96-well plate, blow dry with nitrogen, and then re-dissolve with the re-solution, and the obtained sample is subjected to ultra-performance liquid chromatography-mass spectrometry detection;

[0022] The buffer solution is ultrapure water, the elution solution is one of a methanol solution, a methanol solution with a volume ratio of 2% acetic acid, acetonitrile or acetone, and the reconstitution solution is a methanol-water solution prepared by mixing methanol and water in a volume ratio of 7:3.

[0023] Preferably, the chromatographic detection conditions in S2 are: using a 50mm×3mm, 2.6um chromatographic column of Kinetex XB-C18100A; the detector is a mass spectrometer detector, the measurement mode is positive ion mode, and the monitoring mode is multiple reaction monitoring; the injection volume of the automatic sampler is 10uL; the mobile phase A is: a mixture of water, 0.2% formic acid, and 4mM ammonium acetate, and the mobile phase B is methanol.

[0024] Beneficial effects of the present invention:

[0025] (1) After fine-tuning the experimental parameters, Zr-MOF is evenly wrapped on the surface of the spherical magnetic core to form a uniform sphere. The surface of the sphere contains abundant carboxyl groups, aromatic groups, hydrophobic bonds, π-π bonds, salt bonds, and hydrogen bond binding sites, which are beneficial for providing a huge adsorption area and high-efficiency adsorption force for psychiatric drugs.

[0026] (2) The Zr-MOF surface has pores of 2 to 5 nm, which can effectively exclude proteins in serum.

[0027] (3) The magnetic MOF composite material uses SiO2 to protect the outer surface of Fe3O4, maintaining a high degree of magnetic responsiveness, which is conducive to magnetic separation during the detection process and simplifies the detection process. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 These are transmission electron microscope images of Fe3O4, Fe3O4@SiO2, and Fe3O4@SiO2@UiO-67 in Example 3.

[0029] Figure 2 SEM and TEM images of Fe3O4, Fe3O4@SiO2, and Fe3O4@SiO2@UiO-67.

[0030] Figure 3 This is the electron microscope image of comparative example 1Fe3O4@UiO-66.

[0031] Figure 4 This is the electron microscope image of the uneven surface of Fe3O4@SiO2@UiO-67 in comparative example 3.

[0032] Figure 5 N2 adsorption and desorption curves of magnetic MOF composite materials.

[0033] Figure 6 FTIR spectrum of magnetic MOF composite material.

[0034] Figure 7 Water contact angle test of magnetic MOF composite material.

[0035] Figure 8 The hysteresis loop of Fe3O4@SiO2@UiO-67 and the changes in the solution before and after magnetic separation.

[0036] Figure 9 EDX analysis of Fe3O4@SiO2@UiO-67.

[0037] Figure 10 This is the EDS spectrum of Fe3O4@SiO2@UiO-67.

[0038] Figure 11 This is the XPS spectrum of Fe3O4@SiO2@UiO-67.

[0039] Figure 12 This is a graph showing the recovery rates of different groups on the surface of different magnetic MOF composite materials.

[0040] Figure 13 The potential of Fe3O4@SiO2@UiO-67 at different pH values and the FTIR spectra before and after adsorption of antipsychotic drugs.

[0041] Figure 14 The reusability of Fe3O4@SiO2@UiO-67 and the protein exclusion rate of BSA.

[0042] Figure 15 This is the total ion current chromatogram of the seven psychotropic drugs spiked in Example 3.

[0043] Figure 16 The adsorption kinetics and fitting diagram of antipsychotic drugs on Fe3O4@SiO2@UiO-67.

[0044] Figure 17 The adsorption isotherm of antipsychotic drugs on Fe3O4@SiO2@UiO-67 and its simulated composite diagram.

[0045] Figure 18 This is the effect of the amount of adsorbent on the extraction effect in Example 3.

[0046] Figure 19 This is the effect of the pH value of the buffer solution on the extraction effect in Example 3.

[0047] Figure 20 This is the effect of extraction time on the extraction effect in Example 3.

[0048] Figure 21 The adsorption effect after optimization of various conditions for loading samples into 96-well plates: type of elution solvent, pH and salt ion concentration of the eluent. DETAILED DESCRIPTION

[0049] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments; it should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention; in the embodiments, unless otherwise specified, the means used are conventional means in the art; the terms "comprising", "including" or any other variations thereof used herein are intended to cover non-exclusive inclusions; for example, a composition, step, method, product or apparatus comprising the listed elements is not necessarily limited to those elements, but may include other elements not explicitly listed or elements inherent to such a composition, step, method, product or apparatus; in addition, the technical features involved in the various embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other; the experimental raw materials used in the embodiments of the present invention and the comparative examples are all commercially available products.

[0050] Example 1

[0051] A method for preparing a magnetic MOF composite material for psychiatric drugs in serum comprises the following steps:

[0052] 1) Ferric chloride hexahydrate and anhydrous sodium acetate were mixed uniformly in an ethylene glycol solution, and then transferred to a reactor and reacted at 190°C for 7 hours to obtain a black suspension, which was washed with ethanol and water and dried under vacuum at 50°C for 11 hours to obtain Fe3O4; the mass ratio of ferric chloride hexahydrate, anhydrous sodium acetate, and ethylene glycol was 1:2:1:90;

[0053] 2) The Fe3O4 prepared in step 1) was immersed in 0.9 mol / L dilute hydrochloric acid for 9 hours, washed, and then dispersed in a mixed solution of water, ethanol, and aqueous ammonia, and ultrasonicated for 20 minutes. Ethyl orthosilicate was added and stirred for 11 hours. The product was magnetically separated, washed with ethanol and water, and dried under vacuum at 50°C overnight to obtain Fe3O4@SiO2; the mass ratio of Fe3O4, dilute hydrochloric acid, ultrapure water, ethanol, aqueous ammonia, and aqueous ammonia was 1:190:70:4:4:1;

[0054] 3) The Fe3O4@SiO2, ZrCl4, and biphenyl-4,4'-dicarboxylic acid synthesized in step 2) were dissolved in DMF, ultrasonically stirred for 20 minutes, and then transferred into a reactor and reacted at 130°C for 17 hours. After the reaction, the reaction was washed and dried in vacuo at 50°C for 10 hours to obtain Fe3O4@SiO2@Zr-MOF; the mass ratio of Fe3O4@SiO2, zirconium tetrachloride, biphenyl-4,4'-dicarboxylic acid, and DMF was 1:2:2:400.

[0055] Example 2

[0056] A method for preparing a magnetic MOF composite material for psychiatric drugs in serum comprises the following steps:

[0057] 1) Ferric chloride hexahydrate and anhydrous sodium acetate were mixed uniformly in an ethylene glycol solution, and then transferred to a reactor and reacted at 210°C for 9 hours to obtain a black suspension, which was washed with ethanol and water and dried under vacuum at 70°C for 13 hours to obtain Fe3O4; the mass ratio of ferric chloride hexahydrate, anhydrous sodium acetate, and ethylene glycol was 1:3:1:110;

[0058] 2) The Fe3O4 prepared in step 1) was immersed in 1.1 mol / L dilute hydrochloric acid for 11 hours, washed, and then dispersed in a mixed solution of water, ethanol, and aqueous ammonia, and ultrasonicated for 40 minutes. Ethyl orthosilicate was added and stirred for 13 hours. The product was magnetically separated, washed with ethanol and water, and dried under vacuum at 70°C overnight to obtain Fe3O4@SiO2; the mass ratio of Fe3O4, dilute hydrochloric acid, ultrapure water, ethanol, aqueous ammonia, and aqueous ammonia was 1:210:90:6:6:1;

[0059] 3) The Fe3O4@SiO2, ZrCl4, and biphenyl-4,4'-dicarboxylic acid synthesized in step 2) were dissolved in DMF, ultrasonically stirred for 40 minutes, and then transferred into a reactor and reacted at 150°C for 19 hours. After the reaction, the reaction was washed and vacuum-dried at 70°C for 14 hours to obtain Fe3O4@SiO2@Zr-MOF; the mass ratio of Fe3O4@SiO2, zirconium tetrachloride, biphenyl-4,4'-dicarboxylic acid, and DMF was 1:3:3:600.

[0060] Example 3

[0061] A method for preparing a magnetic MOF composite material for psychiatric drugs in serum comprises the following steps:

[0062] 1) Ferric chloride hexahydrate and anhydrous sodium acetate were mixed uniformly in an ethylene glycol solution, and then transferred to a reactor for reaction at 200°C for 8 hours to obtain a black suspension, which was washed with ethanol and water, and dried under vacuum at 60°C for 12 hours to obtain Fe3O4; the mass ratio of ferric chloride hexahydrate, anhydrous sodium acetate, and ethylene glycol was 1:2.5:1:100;

[0063] 2) The Fe3O4 prepared in step 1) was immersed in 1 mol / L dilute hydrochloric acid for 10 hours, washed, and then dispersed in a mixed solution of water, ethanol, and aqueous ammonia, and ultrasonicated for 30 minutes. Tetraethyl orthosilicate was added and stirred for 12 hours. The product was magnetically separated, washed with ethanol and water, and vacuum-dried at 60°C overnight to obtain Fe3O4@SiO2; the mass ratio of Fe3O4, dilute hydrochloric acid, ultrapure water, ethanol, aqueous ammonia, and aqueous ethyl orthosilicate was 1:200:80:5:5:1;

[0064] 3) The Fe3O4@SiO2, ZrCl4, and biphenyl-4,4'-dicarboxylic acid synthesized in step 2) were dissolved in DMF, ultrasonically stirred for 30 minutes, and then transferred into a reactor and reacted at 140°C for 18 hours. After the reaction, the reaction was washed and vacuum-dried at 60°C for 12 hours to obtain Fe3O4@SiO2@Zr-MOF; the mass ratio of Fe3O4@SiO2, zirconium tetrachloride, biphenyl-4,4'-dicarboxylic acid, and DMF was 1:2.5:2.5:500.

[0065] Comparative Example 1

[0066] A preparation method of Fe3O4@UiO-66 comprises the following steps:

[0067] FeCl3·6H2O (2.31 g) and FeCl2·4H2O (0.85 g) were dissolved in 100 mL of ultrapure water and heated at 65°C under a nitrogen atmosphere for 2.5 h. Subsequently, 10 mL of 25% ammonia water was added to the mixed solution. The mixture was vigorously stirred at 80°C under a nitrogen atmosphere for 30 min. After cooling to room temperature, the black nanoparticles were separated from the solution by a magnet. The nanoparticles were then washed three times with ultrapure water and ethanol and dried in a vacuum at 70°C overnight.

[0068] ZrCl₄ (0.15 g), terephthalic acid (0.13 g), and newly synthesized Fe₃O₄ nanoparticles (0.20 g) were dissolved in 80 mL of N,N-2-methylformamide (DMF). Subsequently, 4 mL of acetic acid was added to the solution. The solution was transferred to an autoclave and heated at 130°C for 12 h. The mixture was then cooled to room temperature, and the magnetic solid was collected and washed three times with ultrapure water and ethanol. It was then dried in vacuum at 70°C overnight to yield Fe₃O₄@UiO-66.

[0069] Comparative Example 2

[0070] A preparation method of Fe3O4@SiO2@UiO-66 comprises the following steps:

[0071] 0.1 g of magnetic Fe3O4@SiO2 was added to a MOF precursor mixture containing ZrCl4 (0.233 g) and terephthalic acid (0.166 g). The mixture was dissolved in 50 mL of DMF under ultrasonication and then stirred at room temperature for 4 hours. The prepared solution was heated at 140°C for 18 hours. Finally, the product was collected by magnetic separation and washed three times with DMF and ethanol. It was then dried in a vacuum at 80°C for 12 hours to obtain Fe3O4@SiO2@UiO-66.

[0072] Comparative Example 3

[0073] A method for preparing Fe3O4@SiO2@UiO-67 with uneven MOF distribution on the surface comprises the following steps:

[0074] The difference from Example 3 is that in step 3), the Fe3O4@SiO2, ZrCl4, and biphenyl-4,4'-dicarboxylic acid synthesized in step 2) are dissolved in DMF and stirred for 2 hours, transferred into a reactor and reacted at 120°C for 24 hours. After the reaction, the mixture is washed and vacuum-dried at 60°C for 12 hours to obtain Fe3O4@SiO2@UiO-67; the mass ratio of Fe3O4@SiO2, zirconium tetrachloride, biphenyl-4,4'-dicarboxylic acid and DMF is 1:2.5:2.5:500.

[0075] Comparative Example 4

[0076] The difference from Comparative Example 2 is that the ligand used is 2-carboxyterephthalic acid.

[0077] Comparative Example 5

[0078] The difference from Comparative Example 2 is that the ligand used is 2-aminoterephthalic acid.

[0079] Comparative Example 6

[0080] The difference from Comparative Example 2 is that the ligand used is 2-hydroxyterephthalic acid.

[0081] Comparative Example 7

[0082] The difference from Comparative Example 2 is that the ligand used is 2,5-pyridinedicarboxylic acid.

[0083] Comparative Example 8

[0084] The difference from Example 3 is that the ligand used is dipyridyl-3,3'-dicarboxylic acid.

[0085] Detection method

[0086] 1. Detection of the Recovery Rate of Psychotropic Drugs in Serum by Magnetic MOF Composites The magnetic MOF composites prepared in the above embodiments and comparative examples were used to perform 96-well plate-magnetic solid phase extraction combined with ultra-performance liquid chromatography-mass spectrometry to analyze four psychotropic drugs and their metabolites in biological samples. The specific steps are as follows:

[0087] Take 12.5 mg of magnetic MOF composite material into a 96-well solid phase extraction plate, add 760 uL of ultrapure water diluent (PH = 7) and 40 uL of serum (the concentration of psychotropic drugs in the total system is 200 ng / mL, and the concentration of risperidone and 9-hydroxyrisperidone is 40 ng / mL) to the solid phase extraction plate, vortex and oscillate for 9 minutes to make the magnetic MOF composite material evenly dispersed in the sample, use a magnet to separate the adsorbent from the solution, pour out the supernatant, and set aside the precipitate.

[0088] Add 1 ml of 2% acetic acid in methanol to the above precipitate, vortex and oscillate for 8 minutes. After sufficient elution, use a magnet at 8000 r / min to separate the adsorbent from the solution. Pour the supernatant into a new 96-well plate, blow dry with nitrogen, and reconstitute with 1 ml of ultrapure water:methanol (3:7) solution. The resulting reaction system is subjected to ultra-high performance liquid chromatography-mass spectrometry detection. The HPLC-MS conditions are as follows:

[0089] A Kinetex XB-C18100A column (50 × 3 mm, 2.6 μm) was used with the mobile phases consisting of (A) ultrapure water (0.2% formic acid and 4 mM ammonium acetate) and (B) methanol. The flow rate was 0.4 mL min –1The column temperature was 50°C. The injection volume was 10 μL. Elution program: 0-0.5 min, 15% B; 0.5-3 min, 15-50% B; 3.01-4 min, 50-100% B; 4.01-5 min, 100-15% B. Curtain gas (CUR): 3.00; Nebulizer gas (GS1): 15.00; Auxiliary heater (GS2): 10.00; IS: 5000.00; TEM: 350.00; CAD: 7.00; Scan mode: Multiple Reaction Monitoring (MRM); Ion source: Turbo Spray, positive ionization.

[0090] 2. Detection of the protein exclusion effect of magnetic MOF composites

[0091] Bovine serum albumin solution was used to simulate the serum environment. 12.5 mg of functionalized magnetic Zr-MOF was weighed into a 1.5 mL centrifuge tube, 1 mL of bovine serum albumin solution was added, and the mixture was vortexed for 9 minutes. The adsorbent was separated using a magnet, and the supernatant was placed in a new centrifuge tube. The protein concentration in the supernatant was determined by the Folin-phenol method. 0.25 mL of the enriched supernatant was placed in a test tube, diluted by half with 0.25 mL of ultrapure water, and then 2.5 mL of Folin-phenol reagent A was added. The mixture was mixed evenly and allowed to stand at room temperature for 10 minutes. 0.25 mL of Folin-phenol reagent B was then added and mixed immediately. After standing at room temperature for 30 minutes, the absorbance at a wavelength of 500 nm was measured. The protein concentration in the enriched sample system was calculated by comparing it with the standard curve. The protein exclusion rate of functionalized magnetic Zr-MOF was calculated according to the following formula:

[0092] BSA rejection (%) = C0 / C f ×100

[0093] C0-Concentration of supernatant after SPE, C f- Initial concentration.

[0094] Table 1 shows the recovery rates of 7 antipsychotic drugs detected by Examples 1 to 3.

[0095]

[0096]

[0097] Table 2 shows the exclusion rate of protein detected by Examples 1 to 3

[0098]

[0099] Table 3 shows the linear equation, linear range, and R of antipsychotic drugs. 2 , LOD, LOQ

[0100]

[0101] Note: R 2 is the correlation coefficient of the standard curve, LOD is the limit of quantification, and LOQ is the limit of detection. Table 4 shows the intra-day and inter-day precision of each antipsychotic drug with different concentrations of Example 3 (n=5)

[0102]

[0103] Table 5 shows the main element contents of Example 3

[0104]

[0105] Table 6 shows the specific surface area, pore volume and pore size of magnetic MOF composite materials

[0106]

[0107] Table 7 is the parameters of the adsorption kinetic model for quetiapine and N-dealkylated quetiapine in Example 3

[0108]

[0109] Note: Qe is the adsorption amount at equilibrium, k1 is the adsorption rate constant of pseudo-first-order kinetic model, k2 is the adsorption rate constant of pseudo-second-order kinetic model, R 2 is the correlation coefficient of the standard curve

[0110] Table 8 is the parameters of the adsorption isotherm model for quetiapine and N-dealkylated quetiapine in Example 3

[0111]

[0112]

[0113] Note: Qmax is the maximum adsorption capacity, K L is the Langmuir constant, K F is the Freundlich constant

[0114] 3. Analysis of Tables and Illustrations

[0115] As shown in Table 1 and Table 2, the recovery rates of the antipsychotic drugs in Examples 1 to 3 are all above 99%. In Table 1, Comparative Examples 1 and 2 are Fe3O4@UiO-66 and Fe3O4@SiO2@UiO-66, respectively. Figure 4As shown, the Zr-MOF of Comparative Example 1 is not evenly covered on the surface of Fe3O4, but is only connected to Fe3O4 on one side. The preparation process of Fe3O4@SiO2@UiO-66 is compared with Examples 1 to 3. The reaction temperature when Zr-MOF is combined with Fe3O4@SiO2 is significantly reduced to 140°C, but the reaction time is doubled. The recovery rates of the antipsychotic drugs in Comparative Examples 1 and 2 are significantly lower than those in Examples 1 to 3. Figure 1 As shown in the TEM image, the nano-sized Fe3O4@SiO2@UiO-67 is spherical, with a huge specific surface area and abundant carboxyl, aromatic, salt, and π-π bonds. It can also provide hydrogen bonding sites, showing excellent adsorption capacity for antipsychotic drugs and can effectively extract almost all drugs in the serum. The protein exclusion rate is also above 98.9%. While enriching the drugs, it can also exclude proteins in the serum sample from the material, thus preventing proteins from mixing into the test samples and effectively eliminating protein interference with chromatography-mass spectrometry detection. At the same time, the sensitive magnetic responsiveness of Fe3O4@SiO2@UiO-67 allows it to be completely separated by the magnetic field during solid-liquid separation, minimizing errors when preparing the test samples.

[0116] As shown in Table 3, the serum concentration of each antipsychotic drug increases linearly with the peak area detected by chromatography-mass spectrometry. As shown in Table 4, when Fe3O4@SiO2@UiO-67 with different concentrations was used to prepare the test samples, the recovery rate of antipsychotic drugs was the highest when the concentration was low. This is because the drug concentration in serum is often trace, and Fe3O4@SiO2@UiO-67 with low concentration can reach adsorption equilibrium more quickly; combined with Figure 15 The total ion current chromatograms of each antipsychotic drug show the differences in chromatographic peaks of different antipsychotic drugs under the chromatographic conditions.

[0117] As shown in Table 5, the content of each element in Fe3O4@SiO2@UiO-67 of Example 3 was measured by TEM mapping. Figure 10 The EDS spectrum of Fe3O4@SiO2@UiO-67 is shown, and characteristic elements such as Fe in Fe3O4, Si in SiO2, Zr and C in Zr-MOF can be clearly observed. The results show that the outer coating is mainly composed of Zr in UiO-67, while the inner core is composed of Fe in Fe3O4, which confirms the core-shell structure of Fe3O4@SiO2@UiO-67. In addition, Figure 9EDX analysis further revealed the distribution of Fe, Si and Zr elements in the Fe3O4@SiO2@UiO-67 nanocomposite. As shown in Table 6, the specific surface area was measured by N2 adsorption and desorption. The pore size of Fe3O4@SiO2@UiO-67 was smaller than that of Fe3O4@SiO2@UiO-66, but the pore volume was larger, indicating that Fe3O4@SiO2@UiO-67 contained a large number of small pores, which effectively prevented the entry of proteins, but maintained a large adsorption area for antipsychotic drugs. The specific surface area, pore size and pore volume of the adsorbent greatly affect its adsorption capacity for the target analyte, and the pore size also has a great influence on the exclusion capacity of macromolecules in serum. Figure 5 The N2 adsorption-desorption isotherms and pore size distribution of Fe3O4, Fe3O4@SiO2 and functionalized magnetic Zr-MOF are shown. Table 6 lists the corresponding data of parameters such as surface area and pore size. These materials all show typical type I N2 adsorption isotherms, indicating that the functionalized magnetic Zr-MOF materials mainly exist in the form of micropores. The gradual synthesis of the composite material corresponds to the increase of specific surface area. Due to the longer organic ligands of UiO-67, the specific surface area of magnetic UiO-67 is smaller than that of magnetic UiO-66, from 252.30 m 2 g -1 Reduced to 221.39m 2 g -1 The pore size also decreases accordingly, the size is 3.21nm, and the pore volume is 0.32cm 3 g -1 The reduction of pore size is more conducive to the exclusion of proteins in serum; the above results show that the synthesized magnetic composite material can help antipsychotic drugs to be freely adsorbed into its pores, and has good application potential as an adsorbent for antipsychotic drugs in biological samples.

[0118] As shown in Tables 7 and 8, the Joint Instructions Figure 16 and Figure 17 As shown in Table 7 and Figure 16 The adsorption kinetics of quetiapine and N-desalkylated quetiapine are shown in Table 8. qt is the adsorption capacity at adsorption time t. The equilibrium time of the two drugs is approximately between 16 and 18 min. qe is the equilibrium adsorption capacity. In(qe-qt) is inversely proportional to time, and t / qt is directly proportional to time. Figure 17 It is expressed as the adsorption isotherm results of quetiapine and N-desalkyl quetiapine, Ce is the concentration at equilibrium, qe increases with the increase of Ce, Ce / qe is proportional to Ce, and Inqe is proportional to InCe.

[0119] Figure 2The morphology of Fe3O4, Fe3O4@SiO2 and Fe3O4@SiO2@UiO-67 nanocomposites was analyzed by TEM. The layer-by-layer coating process during the formation of the core-shell structure is shown in Figure 4. Figure 2 (DF) shows: First, a layer of SiO2 is coated on the surface of magnetic Fe3O4. Figure 2 (D) and (E) clearly show that a thin layer is formed on the outer surface of the magnetic sphere. Using magnetic microspheres as the core, growing inorganic oxides on the outer surface can not only protect the magnetic core from oxidation, but also provide more active sites for the surface of the nanomaterial, making it easier to further functionalize the composite material. Then, a layer of Zr-MOF, namely UiO-67, is grown on the basis of Fe3O4@SiO2. Figure 2 (E) and (F) clearly show that the outer edge of Fe3O4@SiO2 becomes smoother and the outer shell becomes thicker. These results indicate that Zr-MOF successfully grows on the surface of Fe3O4@SiO2, and the prepared Fe3O4@Zr-MOFs nanocomposite material shows a clear core-shell structure. Figure 3 The electron microscope image of Fe3O4@UiO-66 shows that its structure is that Fe3O4 and UiO-66 are only partially connected, and UiO-66 does not wrap Fe3O4. Since the adsorption part is only on the UiO-66 part, and the formed UiO-66 is a frame square structure, it cannot form a spherical structure with the largest surface area in equal volume, and the adsorption capacity is significantly reduced; Figure 4 It is Fe3O4@SiO2@UiO-66. UiO-66 is unevenly wrapped on the surface of Fe3O4@SiO2, part of the Fe3O4@SiO2 area is exposed, and the adsorption area is also reduced, resulting in a decrease in the adsorption recovery rate of antipsychotic drugs.

[0120] Figure 6 The comparative FTIR spectra of Fe3O4 and magnetic MOF are shown. The FTIR spectra show the characteristic peaks of the composite materials synthesized in each step. It can be found from the figure that the Fe-O bond of Fe3O4 magnetic nanomaterials is at 578cm -1 There is a strong characteristic vibration at 471cm -1 and 1097cm -1 Several new characteristic absorption peaks appeared at 660 cm, which should be attributed to the Si-O-Si vibration absorption, corresponding to the silica shell wrapped around the magnetic nanocore, while Fe3O4@SiO2@UiO-67 -1 and 770cm -1Several new absorption peaks appeared, which should be attributed to the stretching vibration of Zr-O-Zr. These results reveal that Fe3O4@SiO2@UiO-67MOF-based magnetic nanocomposites were successfully prepared; Figure 5 The adsorption amount of Fe3O4 and each magnetic MOF under dynamic adsorption pressure changes are shown. The yellow line is the adsorption amount diagram of Fe3O4@SiO2@UiO-67. The adsorption amount increases with increasing pressure, especially in the last section of 0.7~1.0, where the adsorption amount increases the fastest. When the pressure is low, the adsorption amount still remains in the front position, indicating that Fe3O4@SiO2@UiO-67 has high adsorption efficiency for drugs. At the same time, the contact angle diagram shows 104.43° and 133.01°. Both materials show strong hydrophobicity. Compared with Fe3O4@SiO2@UiO-66, the material after coating with UiO-67 is more hydrophobic, proving that Fe3O4@SiO2@UiO-67 is an excellent hydrophobic material, which is more conducive to its dispersion in aqueous solvents and contact with antipsychotic drugs.

[0121] Figure 8 The magnetic properties of Fe3O4@SiO2@UiO-67 were studied by VSM. The hysteresis regression curves of Fe3O4, Fe3O4@SiO2 and Fe3O4@SiO2@UiO-67 are shown in Figure 2. Figure 8 As shown on the left, Fe3O4, Fe3O4@SiO2, and Fe3O4@SiO2@UiO-67 exhibit superparamagnetism at room temperature, with saturation magnetizations of 59.0, 49.4, and 40.4 emu g, respectively. -1 Due to the coating of SiO2 and UiO-67, the saturation magnetization intensity of Fe3O4@SiO2@UiO-67 decreased, which indirectly proved the formation of core-shell structure; in practical application, when uniformly dispersed in water, Fe3O4@SiO2@UiO-67 could be separated and collected by magnet within 3 seconds (such as Figure 8 Therefore, in subsequent experiments, the Fe3O4@SiO2@UiO-67 nanocomposites can be separated and collected by simple magnetic control. In addition, the lower saturation magnetization intensity can alleviate the aggregation of Fe3O4@SiO2@UiO-67, avoid limited mass transfer and improve the corresponding adsorption performance.

[0122] Figure 9XPS analysis was used to further explore the characteristic peaks of the composite materials synthesized in each link. From the XPS wide scan spectrum, it can be seen that the synthesized Fe3O4@SiO2@UiO-67 has characteristic peaks of Fe, O, C, Zr and Si. In the spectrum of Fe 2p, two characteristic peaks at 711.5 and 725.2 eV were observed in the spectrum of Fe3O4@SiO2@UiO-67, corresponding to Fe 2p3 / 2 and Fe 2p1 / 2, which is consistent with the typical characteristics of Fe3O4. The characteristic peak of Si-O (102.6eV) was observed in the spectrum of Si, proving that the SiO2 layer on the outer surface of the Fe3O4 core was successfully coated. Two characteristic peaks of 181.1ev and 182.4ev were observed in the spectrum of Zr, corresponding to Zr-O and O-Zr-O, respectively, proving that a UiO-67 shell was formed on the outer surface of Fe3O4@SiO2. These results confirm the core-shell structure of Fe3O4@SiO2@UiO-67. At the same time, Fe3O4@SiO2@UiO-67 Figure 10 The EDS layer diagram can also be clearly seen.

[0123] Figure 12 It shows that the types and amounts of surface groups of magnetic MOFs prepared with different ligands have different recovery rates of antipsychotic drugs. Figure 12 The different antipsychotic drugs represented by the colored columns in the middle are risperidone, 9-hydroxyrisperidone, quetiapine, N-dealkyl quetiapine, clozapine, aripiprazole, and dehydroaripiprazole from left to right. Among them, the recovery rate of Fe3O4@SiO2@UiO-67 prepared with biphenyldicarboxylic acid is significantly higher than that of other different magnetic MOF materials. Figure 12 When the benzene ring in the ligand on the right is replaced by a pyridine ring, the drug recovery rate will also decrease significantly. Figure 12 The ligands in the middle left are carboxyl-terephthalic acid, amino-terephthalic acid, and hydroxy-terephthalic acid from left to right. It can be seen that the difference in the amount of carboxyl, amino and hydroxyl groups on the surface of Fe3O4@SiO2@UiO-66 causes the difference in recovery rate. Among them, the Fe3O4@SiO2@UiO-66 prepared by hydroxyterephthalic acid has the worst adsorption effect.

[0124] Figure 13 Figure A shows the dynamic change of the Zeta potential of Fe3O4@SiO2@UiO-67 with the pH of the solution. When the pH is distributed toward the acid and base poles, the Zeta potential is the largest, and the Fe3O4@SiO2@UiO-67 magnetic suspension is more stable. When the pH is 7, the Zeta potential is -4.89mV, which can still effectively maintain the stability of the suspension. Figure 13B shows the difference in FTIR spectra of Fe3O4@SiO2@UiO-67 before and after adsorption of antipsychotic drugs. -1 FTIR spectra of Fe3O4@SiO2@UiO-67 adsorbent with and without adsorbed antipsychotic drugs were analyzed within the range of Figure 13 B) FT-IR spectrum of the adsorbent showed that -1 、1540cm -1 and 3455cm -1 Three strong characteristic peaks are shown at the position of the adsorption saturation point, which are attributed to the antisymmetric stretching vibration of the CH bond and the stretching vibration of the OH bond of the aromatic benzene ring. After adsorption, the characteristic peaks of these groups shift to a certain extent, and the CH and OH bonds shift to 1427, 1535 and 3463 cm, respectively. –1 These changes indicate that OH and CH bonds participate in the adsorption process of antipsychotic drugs through hydrogen bond interactions. In addition, about 1650 cm -1 The spectral peaks correspond to the asymmetric and symmetric stretching vibrations of the C=C bond. After adsorption, 1650 cm -1 The peak at π / π is reduced by half, indicating a π-π interaction between Fe3O4@SiO2@UiO-67 and antipsychotic drugs. Antipsychotic drugs are aromatic compounds containing benzene rings, slightly soluble in water, and highly nonpolar. The pores of Fe3O4@SiO2@UiO-67 are rich in carboxyl, hydroxyl, and aromatic groups. Electrostatics, hydrogen bonding sites, π-π bonds, and hydrophobic interactions play a major role in the adsorption of antipsychotic drugs. Therefore, Fe3O4@SiO2@UiO-67 is an excellent adsorbent for antipsychotic drugs.

[0125] The used Fe3O4@SiO2@UiO-67 can be recycled by simple washing with methanol. Figure 14 A shows that the recovery rate of antipsychotic drugs can still maintain a good effect within three adsorption and elution cycles (84.5%-108.4%), and gradually decreases to below 80% after the fourth cycle. The regenerated Fe3O4@SiO2@UiO-67 still maintains a high adsorption effect for antipsychotic drugs after three adsorption and elution cycles, and the protein exclusion rate in each cycle remains above 97% ( Figure 14 B), these results show that Fe3O4@SiO2@UiO-67 has excellent reusability and regeneration ability, and has broad application prospects as an ideal adsorbent for the pretreatment of antipsychotic drugs in serum.

[0126] Figures 18-20 It shows the effect of changes in different conditions of the detection system on drug recovery rate. Figure 21The different antipsychotic drugs represented by the colored columns in the two figures on the left are risperidone, 9-hydroxyrisperidone, quetiapine, N-desalkylated quetiapine, clozapine, aripiprazole, and dehydroaripiprazole from left to right. Figure 21 The rightmost figure shows the effect of salt ion strength in the detection system on recovery rate.

[0127] During the adsorption process, the pH value of the sample system is an important factor that cannot be ignored. Different pH values can affect the charge density and charge polarity on the adsorbent surface, and at the same time affect the existence form of the target analyte, ultimately having different effects on the adsorption of antipsychotic drugs; Figure 19 As shown in Figure 2, the pH value of the sample solution has a significant effect on the recovery of the target analytes, and the best adsorption effect is obtained at pH 7. When pH = 7, the Fe3O4@SiO2@UiO-67 surface is negatively charged ( Figure 19 ), antipsychotic drugs are positively charged at this time, and the classical interaction between the two leads to the best adsorption effect; when pH < 7 or pH > 7, antipsychotic drugs exist in a negatively or positively charged form, while the surface of Fe3O4@SiO2@UiO-67 is negatively or positively charged at this time, and the electrostatic repulsion between the two leads to a decrease in the adsorption effect. Therefore, the recovery rate of antipsychotic drugs first increases and then decreases with the increase of pH.

[0128] The above-mentioned embodiments only express several implementation methods of the present invention. The description thereof is relatively specific and detailed, but it should not be understood as limiting the scope of the invention patent.

[0129] For ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent of the present invention should be based on the attached claims.

Claims

1. An application of Fe3O4@SiO2@UiO-67 in adsorbing psychiatric drugs in serum, characterized in that: The Fe3O4@SiO2@UiO-67 has a core-shell structure, including a magnetic core Fe3O4@SiO2, encapsulated by a UiO-67 metal-organic framework structure. The metal-organic framework structure has pores of 2 to 5 nm on its surface, and the pores contain one or more of carboxyl groups, aromatic groups, hydrophobic bonds, π-π bonds, salt bonds, and hydrogen bond binding sites. The Fe3O4@SiO2@UiO-67 is used to adsorb psychiatric drugs in serum, with an adsorption recovery rate of 94% to 113% and a protein exclusion rate exceeding 95%. The adsorbed psychiatric drugs are one of risperidone, quetiapine, aripiprazole, clozapine, 9-hydroxyrisperidone, N-dealkylquetiapine, and dehydroaripiprazole. The Fe3O4@SiO2@UiO-67 is reusable and regenerative, and the protein exclusion rate of the regenerated Fe3O4@SiO2@UiO-67 remains above 97%.

2. The preparation method of Fe3O4@SiO2@UiO-67 for adsorbing psychiatric drugs in serum according to claim 1, characterized in that: The following steps are involved: 1) dissolving ferric chloride hexahydrate and anhydrous sodium acetate in an ethylene glycol solution and stirring uniformly, then transferring the mixture to a reactor for reaction to obtain a black suspension, which is then washed and dried to obtain Fe3O4; 2) soaking the Fe3O4 prepared in step 1) in dilute hydrochloric acid, washing it, and then dispersing it in a mixed solution of water, ethanol, and ammonia, ultrasonically adding ethyl orthosilicate and stirring it, magnetically separating the product, washing, and drying it to obtain Fe3O4@SiO2; 3) The Fe3O4@SiO2, ZrCl4, and biphenyl-4,4'-dicarboxylic acid synthesized in step 2) were dissolved in DMF and ultrasonically stirred, and then transferred into a reactor for reaction. After the reaction, the Fe3O4@SiO2@UiO-67 was washed and dried to obtain Fe3O4@SiO2@UiO-67.

3. The preparation method of Fe3O4@SiO2@UiO-67 for adsorbing psychiatric drugs in serum according to claim 2, characterized in that: Step 1) The temperature in the reactor is 190-210° C., and the reaction time is 7-9 hours.

4. The method for preparing Fe3O4@SiO2@UiO-67 for adsorbing psychiatric drugs in serum according to claim 2, characterized in that: The concentration of the dilute hydrochloric acid in step 2) is 0.9-1.1 mol / L, the immersion time is 9-11 h, the mass ratio of the Fe3O4, dilute hydrochloric acid, ultrapure water, ethanol, ammonia water and ethyl orthosilicate is 1:190-210:70-90:4-6:4-6:1, the ultrasonic time is 20-40 min, and the stirring time after ultrasonication is 11-13 h.

5. The method for preparing Fe3O4@SiO2@UiO-67 for adsorbing psychiatric drugs in serum according to claim 2, characterized in that: In step 3), the ultrasonic time is 20 to 40 minutes, the stirring time after ultrasonication is 3 to 5 hours, the reactor temperature is 130 to 150°C, the stirring time is 17 to 19 hours, and the mass ratio of the Fe3O4@SiO2, zirconium tetrachloride, biphenyl-4,4'-dicarboxylic acid and DMF is 1:2-3:2-3:400-600.

6. A use of the Fe3O4@SiO2@UiO-67 according to claim 1 for adsorbing psychiatric drugs in serum, characterized in that: The invention discloses a detection method for detecting drugs in serum, comprising adding a Fe3O4@SiO2@UiO-67 composite material to a serum sample to be tested to eliminate protein adhesion and adsorb and enrich psychiatric therapeutic drugs, then magnetically separating the Fe3O4@SiO2@UiO-67 composite material, mixing the Fe3O4@SiO2@UiO-67 composite material with an eluent, fully eluting and magnetically separating to obtain a supernatant, blowing the supernatant to dryness, then adding a re-dissolving solution for re-dissolution, and preparing a detection sample for detection by chromatography-mass spectrometry.

7. A method for detecting drugs in serum using the magnetic MOF Fe3O4@SiO2@UiO-67 composite material prepared by the preparation method according to any one of claims 2 to 5, characterized in that: The method includes adding a magnetic MOFFe3O4@SiO2@UiO-67 composite material to a serum sample to be tested to eliminate protein adhesion and adsorb and enrich psychiatric therapeutic drugs, then magnetically separating the magnetic MOF Fe3O4@SiO2@UiO-67 composite material, mixing the magnetic MOF Fe3O4@SiO2@UiO-67 composite material with an eluent, fully eluting and magnetically separating to obtain a supernatant, blowing the supernatant to dryness, then adding a re-solution for re-dissolution, and preparing a test sample for detection by chromatography-mass spectrometry.

8. The detection method according to claim 7, characterized in that The specific steps include: S1. Place Fe3O4@SiO2@UiO-67 in a 96-well plate solid phase extraction instrument, add serum sample and buffer to the 96-well plate, shake to disperse the Fe3O4@SiO2@UiO-67, magnetically separate the Fe3O4@SiO2@UiO-67, and discard the supernatant; the volume ratio of the buffer to serum is 19:1; S2. Add the elution solution to the Fe3O4@SiO2@UiO-67 in step S1, shake, fully elute and perform magnetic separation, add the supernatant to a new 96-well plate, blow dry with nitrogen, and then re-dissolve with the reconstitution solution. The prepared sample is subjected to ultra-performance liquid chromatography-mass spectrometry detection; The buffer solution is ultrapure water, the elution solution is one of a methanol solution, a methanol solution with a volume ratio of 2% acetic acid, acetonitrile or acetone, and the reconstitution solution is a methanol-water solution prepared by mixing methanol and water in a volume ratio of 7:3.

Images