465 results about "Dimethyl sulfoxide" patented technology

The invention relates to the technical field of biochemical engineering, in particular to a method for preparing chiral alpha-trifluoromethyl alcohol by using imine reductase AtRedAm, trifluoromethyl ketone is reduced into corresponding chiral trifluoromethyl alcohol at an excellent conversion rate by using the imine reductase AtRedAm, and enantioselectivity is high. The reaction depends on an NADPH (Nicotinamide Adenine Dinucleotide Phosphate) coenzyme circulation system, 10% dimethyl sulfoxide is used as a reaction cosolvent, the reaction is carried out in a 100mM (pH = 7.5) phosphate buffer solution for 16 hours, the highest molar conversion rate reaches 99%, and the highest optical purity reaches 95%.

The invention discloses a preparation method of a raspberry-derived exosome loaded with neroli essential oil. The preparation method comprises the following steps: preparing raspberry fruits into homogenate; centrifuging, collecting supernate, adjusting the pH value to 4.07.5, standing, and centrifuging again; taking supernate, adjusting the pH value to 7.2-7.4, adding polyethylene glycol, standing, centrifuging, collecting precipitate, and carrying out resuspension dispersion; performing microfiltration to obtain supernate, and combining electrophoresis dialysis and ultrafiltration concentration to obtain the high-purity raspberry exosome. And diluting the exosome, adding the diluted exosome into a dimethyl sulfoxide solution containing neroli essential oil, carrying out water bath stirring, carrying out ultrafiltration centrifugation, and taking a clear liquid to obtain the exosome loaded with the neroli essential oil. Efficient separation and purification of the raspberry exosome are achieved by applying an isoelectric precipitation technology, then the neroli essential oil is wrapped in the exosome, the stability of the essential oil is improved, the action time is prolonged, meanwhile, the neroli essential oil and active ingredients of the exosome generate a synergistic effect, and the antioxidant activity is jointly enhanced.

The invention relates to natural dye and green chemical industry, and particularly discloses water-soluble biological indigo blue and a preparation method thereof. The water-soluble biological indigo comprises the following raw material components in parts by weight: 80-90 parts of a biological-based indigo concentrated solution; 0.5 to 1 part of dimethyl sulfoxide; 10 to 15 parts of a solubilizer A; 5-10 parts of a solubilizer B; and 10 to 15 parts of deionized water. According to the invention, the bio-based indigo concentrated solution synthesized by a biological method is used as a raw material, the water-soluble compound is innovatively formed through beta-cyclodextrin inclusion and povidone compounding, and the water-soluble compound has relatively high water solubility; the water solubility of the product is greater than or equal to 50g / L, the stability is excellent, the obtained indigo dye is natural in source, environment-friendly and high in water solubility, secondary pollution of the traditional dye to the environment is avoided, and the indigo dye is suitable for sustainable chemical industry and green dyeing and finishing industries and can be widely applied to the fields of textile dyeing, water-based ink, cosmetic color developing agents, medicines and the like.

The invention belongs to the technical field of thermoelectric materials and functional polymer materials, and particularly relates to thermoelectric hydrogel based on synergistic enhancement of zwitterions and a polar solvent as well as a method and application of the thermoelectric hydrogel. The thermoelectric hydrogel is obtained through the steps that a precursor solution is subjected to a polymerization reaction to form a gel matrix, then the gel matrix is soaked in a soaking solution, potassium ferricyanide / potassium ferrocyanide redox couple is introduced, and the thermoelectric hydrogel is obtained, and the precursor solution is prepared from acrylamide, N-isopropylacrylamide, dimethyl sulfoxide, N, N-dimethylformamide, N, N-dimethylformamide, N, N-dimethylformamide, N, N-dimethylformamide, N, N-dimethylformamide and N, N-dimethylformamide. The photoinitiator is prepared by mixing N, N-dimethylformamide, 1-ethyl-3-methylimidazolium tetrafluoroborate, a zwitterionic monomer [2-(methylacryloyloxy) ethyl] dimethyl-(3-sulfopropyl) ammonium hydroxide, a cross-linking agent N, N '-methylene bisacrylamide, a photoinitiator and deionized water. The thermoelectric hydrogel prepared by the invention has high mechanical strength, high ductility and high Seebeck coefficient, and has better temperature resistance.

The invention belongs to the technical field of pharmaceutical preparations, and relates to a compound I patch composition, a compound I patch and a preparation method thereof. The patch composition comprises the following components in parts by weight: 0.5-12 parts of a pharmaceutical active component, 10-30 parts of a penetration enhancer, 15-56 parts of a crystal inhibitor and 35-57 parts of an acrylic acid pressure-sensitive adhesive, the patch composition also comprises solvent dimethyl sulfoxide and absolute ethyl alcohol, and the residual quantity of the dimethyl sulfoxide is not less than 2.0%; wherein the active pharmaceutical ingredient is a compound I, and the structural formula of the compound I is shown in the specification. According to the patch composition containing the compound I, the medicine stability is high, medicine crystallization and impurity generation are effectively avoided or reduced, and the patch containing the compound I has higher stability and safety; the patch composition containing the compound I has more appropriate drug permeability, so that the patch containing the compound I has higher drug effectiveness.

The application discloses a method for selectively extracting metals from waste ternary lithium batteries by using a eutectic solvent. The method uses a eutectic solvent DES synthesized by choline chloride and oxalic acid as an extraction agent, quotes dimethyl sulfoxide DMSO and water as diluents, introduces a circulation and extraction step on the basis of metal element series immersion, i.e. extracts lithium oxalate from the leaching solution with ethanol and recycles the DES by fractional distillation, and makes innovations in recycling of metal lithium and recycling of the DES. The application has the advantages of high efficiency extraction, high precision purification, innovative extraction of lithium element and innovative recovery of the reagent DES.

The invention discloses a folic acid modified active oxygen response type sodium alginate nano-carrier and application thereof, and the preparation method comprises the following steps: firstly synthesizing-Se-Se-FA: stirring dicyclohexylcarbodiimide, 4-dimethylaminopyridine, dimethyl sulfoxide / pyridine, a double-selenium fragment and folic acid at room temperature for 18-22 hours in an argon environment; and carrying out acetone precipitation, centrifugation, washing, rotary evaporation concentration and freeze-drying. The preparation method comprises the following steps: preparing an ALG-Se-FA carrier, stirring sodium alginate, 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride and hydroxysuccinimide in a 2-morpholinoethanesulfonic acid buffer solution, adding DMSO, dissolving a double-selenium fragment and a-Se-Se-FA fragment in DMSO and deionized water, adding the dissolved double-selenium fragment and-Se-Se-FA fragment into a system, stirring, dialyzing, and freeze-drying to obtain the product. According to the carrier, a double-selenium bond ROS response unit and folic acid targeting molecules are introduced through covalent bonds, astaxanthin can be efficiently entrapped and protected, and after the carrier is stable in gastrointestinal environment and reaches a colitis disease part, high ROS level can be responded, and intelligent drug slow release is achieved through folic acid receptor targeting.

The invention relates to the technical field of analytical chemistry, in particular to a high performance liquid chromatography detection method of a ridecevir intermediate GS-441524, which comprises the following steps: preparing a sample: taking a GS-441524 test sample, dissolving and diluting with a mixed solution composed of dimethyl sulfoxide and a phosphoric acid solution to prepare a test sample solution; the volume fraction of phosphoric acid in the phosphoric acid solution is 0.05-0.1%, and the volume ratio of dimethyl sulfoxide to the phosphoric acid solution is (30: 70)-(60: 40). According to the application, the ridecevir intermediate GS-441524 is dissolved and diluted through the mixed solution composed of the dimethyl sulfoxide and the phosphoric acid solution, and due to the high solubility of the dimethyl sulfoxide to the ridecevir intermediate GS-441524 and the high boiling point of the dimethyl sulfoxide, the ridecevir intermediate GS-441524 with relatively high concentration can also be subjected to high performance liquid chromatography.

This invention relates to the field of hafnium carbide technology and discloses a thermal decomposition preparation process for hafnium carbide precursors. The process includes: dissolving hafnium tetrachloride in anhydrous ethanol, adding propylene oxide dropwise for neutralization and acid removal to obtain a neutral ethanol-hafnium precursor solution; adding ethyl acetoacetate methacrylate and heating for coordination to obtain a hafnium coordination monomer solution; adding acrylonitrile and an initiator and heating for polymerization; when the viscosity of the reaction solution increases, injecting a dimethyl sulfoxide hot solution of melamine as a locking liquid; precipitating, separating, and drying to obtain the hafnium carbide precursor; and after oxidative crosslinking treatment, calcining at high temperature under an inert atmosphere to undergo carbothermic reduction to obtain hafnium carbide powder. This invention achieves molecular-level dispersion of precursor components through liquid-phase coordination and in-situ network locking, effectively reducing the reaction temperature and inhibiting grain agglomeration, thus producing high-purity, ultrafine hafnium carbide powder.

This invention belongs to the field of two-dimensional material preparation technology, and provides an MXene material and its preparation method. The preparation method of the MXene material includes: mixing a MAX phase precursor to be etched with an organic halide reagent and a morphology modifier, performing a solvothermal etching reaction, and after the reaction, washing and drying the resulting product to obtain the MXene material; wherein the organic halide reagent is triethylamine trihydrofluoride, triethylamine hydrochloride, or dichloroethylamine hydrochloride, and the morphology modifier is ethylene glycol, dimethyl sulfoxide, or cyclohexane. The method of this invention can effectively control the microstructure and pore structure of the MXene material.

The invention discloses a preparation method and application of a mitochondrial targeting polypeptide modified carbon quantum dot probe, and relates to the technical field of nano biological materials and fluorescence imaging.The preparation method comprises the steps that citric acid and urea are dissolved in a dimethyl sulfoxide solution, mixed, heated, filtered, added with ethyl alcohol, centrifuged and freeze-dried, and carbon quantum dots are obtained; adding an MES buffer solution and an activating agent, reacting the polypeptide at room temperature, heating, reacting, centrifuging, dialyzing and freeze-drying to obtain polypeptide modified carbon quantum dots; the carbon quantum dots are synthesized from bottom to top, and the preparation method is simple. After polypeptide modification, the product has an obvious mitochondrial targeting effect, and the product is good in biocompatibility, so that the product can be used for imaging and dynamic tracking of living organelles. The probe developed by the invention shows obvious application potential in key cell events such as mitochondrial dynamic monitoring and the like.

The application discloses a preparation method of polyvinyl alcohol-based electromagnetic shielding conductive hydrogel, which comprises the following steps: (1) preparing a high-concentration dimethyl sulfoxide aqueous solution; adding polyvinyl alcohol into the dimethyl sulfoxide aqueous solution, and heating and stirring to completely dissolve the polyvinyl alcohol, so as to obtain a mixed solution; (2) placing the mixed solution after standing in a mold, and freezing at low temperature to obtain a PVA gel; (3) preparing an electrolyte salt solution, wherein the electrolyte salt solution contains low-concentration dimethyl sulfoxide; and placing the PVA gel in the electrolyte salt solution, so as to obtain the polyvinyl alcohol-based electromagnetic shielding conductive hydrogel after ion exchange. The polyvinyl alcohol-based electromagnetic shielding conductive hydrogel prepared by the method has high transparency, strength and ionic conductivity, the light transmittance is up to 75.2%, the compression resistance at a strain of 80% is up to 2.97 MPa, the ionic conductivity is up to 10.34 mS / cm, and the effective electromagnetic shielding performance (>30 dB) can be maintained for more than 60 hours at a low temperature of-60 DEG C.

The application discloses an electrode material based on MOF@COF / BC and application thereof in wastewater treatment and belongs to the technical field of wastewater treatment. The electrode material is prepared by the following method: NH2-MIL101(Fe), melamine and phthalocyanine molybdenum are dissolved in dimethyl sulfoxide, reaction is carried out at 160-200 DEG C for 10-14 h, the precipitate is collected after reaction, and washing, drying are carried out to prepare NH2-MIL101(Fe)@Mel-MoPc; the biochar and NH2-MIL101(Fe)@Mel-MoPc are mixed in deionized water, ultrasonic treatment is carried out for 8-12 min, stirring is carried out for 10-14 h, then the precipitate is collected by centrifugation, and washing, drying are carried out to prepare the electrode material. The application develops and designs a novel electrode material, which is used for electrocatalytic activation of peroxymonosulfate to degrade OFX wastewater, and the degradation efficiency of the OFX wastewater is greatly improved.

A process to produce cellulose ester fibers is provided, the process comprising: a. mixing cellulose ester and at least one solvent at a temperature ranging from about 60 ℃ to less than 90 ℃ to produce a cellulose ester dope; wherein the solvent comprises N, N-dimethylformamide, N, N-dimethylacetamide, or dimethyl sulfoxide, or mixtures thereof; and b. spinning the cellulose ester dope through at least one spinneret to produce the cellulose ester fibers; wherein the cellulose ester fibers have improved color over cellulose ester fibers produced from dope mixed outside about 60 ℃ to less than 90 ℃.

The application provides an alkali-resistant nanofiltration membrane wire and a manufacturing method thereof, and relates to the technical field of nanofiltration membranes.The manufacturing method comprises the following steps: mixing and crushing amino-modified cellulose, polyamide, polyethylene glycol and dimethyl sulfoxide to form a spinning solution, and preparing a nascent membrane through dry-jet wet spinning; the nascent membrane is put into a coagulation bath to be solidified to prepare a hollow fiber base membrane; the mass ratio of the amino-modified cellulose, the polyamide, the polyethylene glycol and the dimethyl sulfoxide is 1:3-5:0.2-0.5:2-10; propylene oxide, water, aniline monomer and an initiator are prepared into a casting solution according to the mass ratio of 1:5-10:1-3:0.01-0.1; the hollow fiber base membrane is immersed in the casting solution for 2-3 hours, is heated to 35-45 DEG C for cross-linking reaction for 2-4 hours, and is dried and washed.The alkali-resistant nanofiltration membrane wire has good alkali resistance, separation performance and permeation performance.

The invention discloses a preparation method for direct trifluoromethylation of pyrimidinedione herbicides under visible light catalysis, and belongs to the technical field of photocatalytic organic synthesis and the technical field of pesticide herbicides. The preparation method for direct trifluoromethylation of the pyrimidinedione weeding drug under visible light catalysis comprises the following steps: S1, mixing a photocatalyst, the pyrimidinedione weeding drug, a trifluoromethylation reagent, copper acetate, triethylamine and dimethyl sulfoxide, and carrying out a photocatalytic reaction under visible light; s2, after the reaction is finished, adding a saturated sodium chloride solution and dichloromethane for extraction, and collecting an organic phase; and S3, concentrating the organic phase, and purifying through silica gel column chromatography to obtain the 5-trifluoromethylated pyrimidinedione product. The method provided by the invention uses visible light energy as an energy source, has the advantages of simple operation, low cost and the like, and fills the vacancy of direct trifluoromethylation of pyrimidinedione herbicides.

The invention relates to a synthesis method of an allyl amine compound. According to the method, 2-methylquinoline or acetophenone derivatives are used as raw materials, a selective fluorine reagent Selectfluor is used as an accelerant, dimethyl sulfoxide and N 'N-dimethylacetamide are used as a mixed solvent, and the allyl amine series compounds are prepared with high yield. The preparation method has the advantages of being low in cost, easy to operate, green, free of pollution and the like, and has potential industrial application prospects. The method provides a green, cheap and convenient way for preparing the allyl amine derivative by using 2-methylquinoline or acetophenone compounds as initiators.

The present application provides a forsythoside crystal form, which is a forsythoside hydrate crystal form, a forsythoside anhydrate crystal form, a forsythoside isopropanol compound crystal form, a forsythoside 1,4-dioxane compound crystal form, a forsythoside tetrahydrofuran compound crystal form or a forsythoside dimethyl sulfoxide compound crystal form. The present application also provides a preparation method of the forsythoside crystal form. The preparation method of the present application is safe and simple, and the prepared forsythoside crystal form has good stability.

This invention belongs to the field of biomaterial preparation technology, specifically disclosing a self-assembled supramolecular peptide nanozyme material, its preparation method, and its application. The preparation method includes the following steps: S1, dissolving β-alanyl-L-histidine in ultrapure water and stirring until homogeneous to obtain solution A; S2, dissolving heme chloride in dimethyl sulfoxide and stirring until homogeneous to obtain solution B; S3, mixing solution A and solution B until homogeneous, adjusting the pH, heating in a water bath, incubating at room temperature, centrifuging, discarding the precipitate, and retaining the supernatant; S4, lyophilizing and grinding the supernatant obtained in S3 to obtain the self-assembled supramolecular peptide nanozyme material. This invention discloses a self-assembled supramolecular peptide nanozyme material, its preparation method, and its application. This supramolecular peptide nanozyme, when applied to food quality and safety testing, can achieve visual and sensitive colorimetric detection of biogenic amines in spoiled food.

This invention relates to the field of organic synthetic chemistry, specifically to a polysubstituted furan compound and its synthetic method, wherein the method comprises... β Using ketone sulfones and olefins as starting materials, polysubstituted furans are synthesized via a [3+2] cycloaddition reaction in the presence of a copper catalyst and an oxidant. This invention employs cuprous bromide as the catalyst and di-tert-butyl peroxide (DTBP) as the oxidant, reacting in dimethyl sulfoxide solvent at 100°C–130°C for 6–24 h. This method offers advantages such as high atom and step economy, broad substrate applicability, good functional group tolerance, excellent position selectivity, and high yield, with a maximum yield reaching 84%. It is suitable for large-scale synthesis and provides a new strategy for the synthesis of furans in medicinal chemistry and materials science.

The application relates to a synthesis method of a positive electric three-component covalent organic polymer and application thereof, and belongs to the technical field of sewage treatment. The method is as follows: 1,3,5-benzene triformylhydrazine is dissolved in an organic solvent dimethyl sulfoxide to obtain a solution A; 1,3-diamino guanidine hydrochloride is dissolved in the solution A to obtain a solution B; 2,3,5,6-tetrafluoro-p-xylene dicarboxaldehyde is dissolved in the solution B to obtain a solution C, and the preparation of the solutions is carried out in a constant-temperature oil bath; then, the orange wet gel is obtained by heating at 100 DEG C for 30s; the orange wet gel is placed in a dialysis bag for dialysis, the mixture is taken out for freezing, and then the freezing drying is carried out under vacuum to obtain the positive electric three-component covalent organic polymer. The synthesis method is simple, high in yield and fast in speed, the specific surface area of the positive electric three-component covalent organic polymer is large, the positive electric three-component covalent organic polymer has a hierarchical porous structure and rich reaction active sites, and can be used as a high-efficiency adsorbent to remove perfluorooctanoic acid in water.

The application discloses a bleaching agent and a preparation method and application thereof, and relates to the technical field of bleaching agents. In one aspect, the bleaching agent comprises A component and B component, and the mass ratio between the A component and the B component is 1-2:1-3; the A component comprises the following raw material components in weight percentage: 45-60 parts of sodium ferrate, and 5-10 parts of active ceramic particles; the B component comprises the following raw material components in weight percentage: 20-30 parts of peroxo-benzoic acid, 25-40 parts of dimethyl sulfoxide, and 50-75 parts of water. In another aspect, the application further provides a preparation method and application of the bleaching agent. The bleaching agent provided by the application has the advantages of good stability, less residual amount, and safety and environmental protection.

The invention discloses a surface protection layer of an ultrathin lithium strip as well as a preparation method and application of the surface protection layer, and belongs to the technical field of lithium batteries. The surface protection layer is formed after lithium metal reacts with a composite additive, and the composite additive is composed of solid powder and an organic solvent; wherein the solid powder is selected from one or more of dialkyl dithiophosphate or metal fluoride; the organic solvent is selected from any one of dimethyl sulfoxide, formamide, butyrolactam, acetone, 1, 4-dioxane, tetrahydrofuran, trimethyl phosphate, triethyl phosphate and propylene carbonate. The electrochemical performance of the produced lithium strip with the surface protection layer is remarkably improved, large-scale production can be achieved on the premise that existing equipment is not transformed and technological processes are not increased by means of the preparation method, the technical advantages in cost and technology are achieved, and therefore the lithium strip with the surface protection layer has a good application prospect. The surface protection layer of the ultrathin lithium strip and the preparation method of the surface protection layer have good application prospects.

The invention provides a rapid detection kit and a rapid detection method for phytosterol, and belongs to the field of food detection.The rapid detection kit for phytosterol comprises a phytosterol standard substance, a standard substance diluent, a substrate solution, an enzyme mixed solution, a stop solution and an elisa plate; the standard substance diluent comprises isopropanol or dimethyl sulfoxide; the substrate solution is prepared from TMB (Tetramethylbenzidine) and a substrate buffer solution; the enzyme mixed solution is a mixed solution of a cholesterol oxidase solution and a horse radish peroxidase solution. By optimizing the composition of each working reagent in the kit, the sensitivity and accuracy of phytosterol detection are remarkably improved. Meanwhile, the rapid detection method provided by the invention is simple and convenient to operate, short in detection time and suitable for on-site rapid detection.

The invention relates to the technical field of polymer materials, in particular to a preparation method of ultrafine aramid nanofiber dispersion liquid, which comprises the following steps: primarily crushing aramid III fibers to obtain pre-stripped fibers; placing the pre-stripped fiber in a potassium hydroxide / dimethyl sulfoxide / water system, stirring, and carrying out a deprotonation reaction to obtain an initial dispersion liquid with the aramid fiber concentration of 10-50 mg / mL; and standing the primary dispersion liquid at normal temperature, and further cracking the aramid fibers to obtain the ultrafine ANF dispersion liquid. According to the preparation method, high-yield and low-energy-consumption preparation of the ultrafine ANF is realized, the problem of rapid and high-yield preparation of the ANF with the size of less than 5 nanometers is solved, and the product has higher specific surface area and surface activity, higher mechanical property, better loading capacity and more excellent function regulation and control capacity and is suitable for industrial production. The method has wide application potential in the high-technology frontier fields such as aerospace, flexible electronics, advanced filtering, energy storage devices and intelligent composite structures.

The disclosure provides a surface polishing method of a perovskite crystal material, comprising: performing hot mounting treatment on a perovskite single crystal to be polished to obtain a perovskite single crystal sample; fixing the perovskite single crystal sample on a polishing table and performing rough polishing on the perovskite single crystal sample; and performing fine polishing on the rough-polished perovskite single crystal sample to obtain a polished perovskite single crystal sample, wherein the process of fine polishing comprises: using artificial leather polishing cloth and performing first drop processing using anhydrous ethanol as a polishing liquid; and after a preset time interval elapses after the first drop processing, replacing the anhydrous ethanol with a suspension of dimethyl sulfoxide and anhydrous ethanol for second drop processing.

The application discloses a polyketone filter membrane containing a composite pore structure and a preparation method thereof, and belongs to the technical field of organic filter membranes. Aliphatic polyketone is used as a main body resin, is uniformly mixed with an additive and a diluent dimethyl sulfoxide at 130-160 DEG C, and a filter membrane is prepared through a composite thermally induced phase separation method. The preparation method is simple, safe and environmentally friendly. The prepared membrane has the membrane structure characteristics of a non-solvent induced phase separation method and a thermally induced phase separation method, has a finger-shaped pore and a double-continuous net-shaped composite structure, and has a low price, good hydrophilicity and good solvent resistance. The aliphatic polyketone has a good application prospect in the field of membrane separation.

The application belongs to the technical field of medicine, and relates to a compound composition, a preparation method and application, in particular to a compound sodium salicylate composition for treating acute pancreatitis and a preparation method. The compound sodium salicylate composition comprises quercetin, diammonium glycyrrhizinate and sodium salicylate, wherein the mass ratio of quercetin, diammonium glycyrrhizinate and sodium salicylate is 1-5:5-20:50-200. When the compound sodium salicylate composition is an injection, it comprises quercetin, diammonium glycyrrhizinate, sodium salicylate, 1,2-propanediol, sodium bisulfite, dimethyl sulfoxide and 0.9% sodium chloride injection. The volume ratio of 1,2-propanediol and dimethyl sulfoxide in the injection is 14-20% and 0.25-1% respectively; and the mass / volume ratio of sodium bisulfite in the injection is 0.1-0.3%. The compound sodium salicylate composition can significantly reduce amylase, lipase, IL-6 and IL-1beta, and can be used for preparing a medicine for treating pancreatitis.

The invention discloses a method for quantitatively analyzing the content of dimethyl furandicarboxylate (DMFDCA) through a nuclear magnetic resonance hydrogen spectrum technology, which adopts an internal standard substance ethylparaben which meets the national standard and does not react with a standard substance to directly measure the content of the main component DMFDCA in the standard substance. The method comprises the following steps: dissolving ethylparaben and DMFDCA in deuterated dimethyl sulfoxide DMSO-d6 to obtain a solution to be detected, optimizing test parameters, determining a nuclear magnetic resonance hydrogen spectrum of the solution to be detected, selecting proper quantitative peaks of ethylparaben and DMFDCA, respectively integrating the quantitative peaks of ethylparaben and DMFDCA to obtain integral areas, and calculating the actual content of DMFDCA according to a formula. The method has the characteristics of simplicity, feasibility, low cost, good stability, high precision, strong specificity and the like, and has wide application prospects in the aspects of standard substance calibration, intermediate check and the like.

The application discloses a modified organosilicon defoaming agent and a preparation method thereof, and relates to the technical field of defoaming. The modified organosilicon defoaming agent and the preparation method thereof comprise the following components by mass ratio: 89.57 g of liquid mercaptan silicone oil, 20.30 g of triethylamine, 89.57 g of dimethyl sulfoxide, 3.45 g of a methyl-terminated allyl polyoxyethylene ether, 13.80 g of a methyl-terminated allyl polyoxypropylene ether, 0.34 g of azobisdimethyl isobutyronitrile, 32.25 g of butyl acetate, 19.29 g of 2-bromoisobutyrate methyl ester, a magnesium sulfate and sodium chloride aqueous solution, a coupling agent and a thickening agent. The modified organosilicon defoaming agent has good defoaming performance and bubble inhibiting performance, has strong compatibility with different emulsions, and has defoaming performance and bubble inhibiting performance equivalent to polyether defoaming agents in a water-based resin system.