116 results about "4-Nitrophenol" patented technology

The invention discloses a methyl paraoxon pesticide detection test strip based on oxygen vacancy-cerium dioxide and a preparation method of the methyl paraoxon pesticide detection test strip, and belongs to the technical field of biosensors. The test strip is characterized in that a large amount of oxygen vacancy-cerium dioxide is loaded. The oxygen vacancy-cerium dioxide nano enzyme can show simulated phosphatase activity under specific conditions, and the enzyme activity can cut off P-O and P-S bonds of organophosphorus pesticides and promote methyl paraoxon to be hydrolyzed into a yellow product p-nitrophenol. The detection limit of a nano-enzyme system is discussed, so that the portable visual quantitative detection of the paraoxon methyl pesticide is realized. The test strip established on the basis of the principle can quickly detect paraoxon methyl, has the advantages of simplicity and convenience in operation, high sensitivity, low cost and the like, and provides a new method for instant test of paraoxon methyl pesticide.

The invention belongs to the technical field of analytical chemistry and pesticide residue detection, and relates to a phosphate hydrolysis nano-enzyme sensing array-based p-nitrophenol pesticide identification and detection method, which comprises the following steps of: performing five groups of parallel data matrixes on each type of p-nitrophenol pesticide to distinguish single / five types of p-nitrophenol pesticides with different concentrations; establishing a discrimination model of different concentrations / types of pesticides by using the data matrix, and obtaining an HCA map and an LDA score map of the p-nitrophenol pesticides through hierarchical clustering analysis and linear discriminant analysis; after the absorbance value of the sample to be detected is measured, the sample to be detected can be identified and detected through comparison. According to the present invention, by using the inherent dynamic difference existing during the catalytic hydrolysis of different p-nitrophenol pesticides by CeO2, a plurality of reaction time points are selected to measure the absorbance change, the time-resolved sensing array fingerprint is constructed, and the type identification and the concentration quantification of a variety of p-nitrophenol pesticides and the mixture thereof are achieved by combining the pattern identification algorithm, such that the sensitivity is high, and the detection result is accurate. The measurable concentration range is 1-50 mu g / mL.

The invention provides a cerium-zirconium loaded cobalt titanate solid solution nanosphere water treatment catalyst and a preparation method thereof, and relates to the field of water treatment. The cerium-zirconium loaded cobalt titanate solid solution nanosphere water treatment catalyst comprises nano spherical ferroferric oxide, a cerium-zirconium solid solution, cobalt titanate and D-(-)-quinic acid, the nano spherical ferroferric oxide serves as an inner core, the cerium-zirconium solid solution serves as an electron transport middle layer, the cobalt titanate serves as an active component outer layer, and the D-(-)-quinic acid serves as a morphology control agent. On the basis of the mass of the ferroferric oxide inner core, the mass percentage content of the electron transmission middle layer is 60%-80%, and the mass percentage content of the active component outer layer is 20%-40%; wherein the molar ratio of cerium oxide to zirconium oxide in the cerium-zirconium solid solution is 1: (0.33-3). The catalyst provided by the invention is environment-friendly, not only can efficiently catalyze and reduce p-nitrophenol, but also can be repeatedly used, is simple to regenerate, and has higher economic value and wide market application prospect.

The present invention provides a chemical synthesis method of EPS-G7, wherein β-cyclodextrin A is acetylated to obtain β-acetylcyclodextrin B, B is ring-opened in a mixed solution of acetic anhydride / concentrated sulfuric acid to obtain a chain acetylated heptose C, p-nitrophenol is condensed with intermediate C using boron trifluoride acetonitrile to obtain a key intermediate p-nitrophenyl (G1)-O-acetyl-D-maltoseptaglycoside D with α as the dominant configuration, D is removed from the acetyl group under the action of sodium methoxide to obtain pNP-G7 (p-nitrophenyl (G1)-D-maltoseptaglycoside), pNP-G7 is in the presence of p-toluenesulfonic acid and dimethoxyethane, and acetal protection is formed between the hydroxyl groups on C4 and C6 of the terminal monosaccharide to obtain EPS-G7. The reaction raw materials used in the method of the present invention are cheap and readily available, and the chemical synthesis of α-amylase detection reagent EPS-G7 is realized, which is a simple, economical and efficient synthesis method.

The invention discloses nearly-spherical silver powder formed by self-assembly of silver nanosheets and a preparation method and application of the nearly-spherical silver powder, and belongs to the technical field of micro-nano material preparation. The preparation method comprises the following steps: firstly, adding a dispersing agent solution into a silver precursor compound solution, stirring, then adding a morphology control agent solution, stirring, and finally adding a reducing agent solution for reaction; and after the reaction is completed, the prepared silver powder is washed and dried, and the nearly-spherical silver powder formed by self-assembly of the silver nanosheets is obtained. The nearly-spherical silver powder is formed through self-assembly of the silver nanosheets, the particle size range of the nearly-spherical silver powder is 0.5-2.0 m, the thickness range of the self-assembled silver nanosheets is 10-50 nm, the overall size is uniform, a large number of stacking faults exist on the surfaces of the silver nanosheets, and the silver nanosheets show an excellent catalytic effect in conversion of p-nitrophenol into p-aminophenol.

The invention belongs to the field of soil environment pollution simulation and prediction, and provides a prediction method based on a two-point chemical unbalanced model, which is used for quantitatively evaluating the effect of regulating and controlling the migration behavior of p-nitrophenol in acid red soil by straw stalk biochar. According to the method, a biochar-red soil composite medium system is constructed, a soil column leaching experiment is carried out to obtain penetration curve data, a two-point chemical unbalance model in CXTFIT software is utilized to carry out parameter inversion, and key parameters such as a retardation factor, a two-region distribution coefficient, a mass transfer coefficient and a liquid phase degradation coefficient are accurately identified. Model verification shows that the goodness of fit is high, and a parameter change rule reveals the inherent mechanism of enhancing the pollutant retention capacity, changing the proportion of fast and slow adsorption sites and influencing mass transfer kinetics by the biochar. Based on the verified model, the long-term migration behavior and pollution risk of p-nitrophenol under different environmental conditions can be simulated, and a scientific basis is provided for groundwater pollution control and remediation strategy optimization.

The invention discloses a zinc / cobalt-based spinel oxide composite material catalyst as well as a preparation method and application thereof. The zinc / cobalt-based spinel oxide compound catalyst is prepared by taking zinc sulfate, cobalt nitrate and potassium oxalate as metal nodes and ligands through hydrothermal treatment and calcination. The ZnCo2O4 disclosed by the invention is applied to reduction of p-nitrophenol as a high-efficiency catalyst, and under the condition of room temperature, sodium borohydride is used as a reducing agent, and the efficiency of converting p-nitrophenol into p-aminophenol within 4 minutes can reach 100%. The zinc / cobalt-based spinel oxide composite material catalyst is synthesized by adopting a simple and environment-friendly method, the sodium p-borohydride has extremely high catalytic activity in reduction of p-nitrophenol, p-nitrophenol with relatively high toxicity can be reduced into p-aminophenol with relatively low toxicity, and the zinc / cobalt-based spinel oxide composite material catalyst has a potential application prospect in the fields of sewage treatment and the like.

The invention belongs to a fluorescence analysis and detection method of p-nitrophenol, and particularly relates to a fluorescent carbon quantum dot probe for detecting p-nitrophenol as well as a preparation method and application of the fluorescent carbon quantum dot probe. The specific preparation method of the fluorescent carbon quantum dot probe comprises the following steps: taking aminopyrimidine as a precursor, mixing aminopyrimidine with water, and reacting at 160-200 DEG C to obtain the fluorescent carbon quantum dot probe with the surface rich in hydroxyl, amino and carboxyl groups. The fluorescent carbon quantum dot probe prepared by the invention has a strong fluorescent signal, selectively responds to p-nitrophenol, shows a wider linear detection range and high anti-interference capability, and is suitable for complex environmental pollutant detection.

The invention discloses a process for continuously separating tar from p-nitrophenol, and relates to the technical field of p-nitrophenol, which comprises the following steps: adding nitrobenzene and a sodium hydroxide solution into a microwave reactor in proportion, hydrolyzing at a certain temperature and pressure under the assistance of ultrasonic waves, and filtering to obtain a filtrate; performing counter-current extraction on the obtained hydrolysate through an alkaline water phase, a polar organic solvent phase and an ionic liquid phase in sequence, then performing rotary evaporation under the conditions that the vacuum degree is (-0.08)-(-0.095) MPa and the temperature is 50-70 DEG C, and collecting fractions; the temperature of the upper section of the spiral packing layer is 40-50 DEG C, the temperature of the middle section of the spiral packing layer is 60-70 DEG C, the temperature of the lower section of the spiral packing layer is 80-90 DEG C, and finally high-purity p-nitrophenol is obtained. In the process, the conversion rate of nitrobenzene is higher, and the prepared p-nitrophenol has higher purity.

The invention discloses an application of a copper nano-cluster with stable ascorbic acid in detection of p-nitrophenol, the copper nano-cluster with stable ascorbic acid is used as a fluorescent probe, and the detection of p-nitrophenol is realized through a fluorescent sensing method. Due to the quenching effect of p-NP, the fluorescence intensity of the system is obviously reduced in the presence of p-NP. The p-NP concentration can be quantitatively detected by comparing the fluorescence intensity of the copper nano-cluster and the fluorescence intensity of a quenching system. The method is simple, sensitive and high in selectivity, does not need complex fluorescent dye labeling, shows remarkable potential for p-NP detection, and has a good application prospect in the aspects of food, medicine and the like.

The invention discloses an aluminum alloy material easy to oxidize and color and a preparation method thereof.The aluminum alloy material is prepared from, by weight, 20-25 parts of aluminum alloy powder, 5-10 parts of graphene, 4-6 parts of p-nitrophenol, 0.5-1 part of concentrated bromine water and 4-7 parts of magnesium powder. And graphene treatment, aluminum alloy and graphene dispersion treatment, drying, water washing and vacuum hot pressing are carried out. Graphene is doped with the aluminum alloy, the comprehensive performance of the aluminum alloy can be remarkably improved, the hardness can be improved, the electrical conductivity and the thermal conductivity can be remarkably improved, halogen elements are introduced, the activity of the aluminum alloy is improved, the oxidized capacity is improved, the coloring efficiency is improved, and the flame retardant property is improved; and the magnesium powder is added, so that the stability of the system is protected, and the hardness of the system is improved.

The invention belongs to the technical field of membrane catalysis, and relates to a method for reducing the Co particle size of a multi-channel Co / CM catalytic membrane. And coating the surface of the Co / CM catalytic membrane with a polydopamine coating, and then drying and calcining the Co / CM catalytic membrane. According to the method for reducing the particle size of Co in the Co / CM catalytic membrane, the particle size of Co can be effectively reduced, so that the active component Co in the catalytic membrane is re-dispersed, and the activity of the catalytic membrane in a p-nitrophenol catalytic hydrogenation reaction is obviously improved.

The present invention provides a bimetallic ZIFs-supported nanocatalyst, a preparation method, and an application thereof. The bimetallic ZIFs-supported nanocatalyst of the present invention comprises a Zn-Cu bimetallic ZIFs material and metal Cu(0) supported on the Zn-Cu bimetallic ZIFs material. The preparation method of the catalyst of the present invention comprises: contacting a dispersion of the Zn-Cu bimetallic ZIFs material with a reducing agent to obtain the bimetallic ZIFs-supported nanocatalyst. The catalyst of the present invention exhibits high catalytic activity and stability in the catalytic degradation of p-nitrophenol.

The invention discloses a polyelectrolyte multilayer film loaded gold-palladium bimetallic nanoparticle catalyst, which is characterized in that cationic polyelectrolyte poly (diallyldimethylammonium chloride) PDDA and anionic polyelectrolyte sodium polystyrenesulfonate (PSS) are used as construction materials, a layer-by-layer self-assembly technology is adopted to prepare a polyelectrolyte multilayer film, and the polyelectrolyte multilayer film is marked as (PDDA / PSS) n + 0.5, and firstly loading gold nanoparticles on the multilayer film through an ion exchange-in-situ reduction method, and then loading palladium nanoparticles on the multilayer film to obtain the catalyst (PDDA / PSS) (n + 0.5 / a) AubPd for catalyzing the degradation of p-nitrophenol. According to the polyelectrolyte multilayer film loaded gold-palladium bimetallic nanoparticle catalyst disclosed by the invention, by selecting and designing the material and the layer number of the multilayer film carrier and the proportion of gold and palladium bimetallic, the synergistic catalysis of the polyelectrolyte film and the gold-palladium bimetallic nanoparticles is exerted; the catalytic efficiency and the degradation effect of the catalyst in the p-nitrophenol degradation process are obviously improved.

The preparation method comprises the following steps: dissolving sodium alginate and carbon black in water, adding polyacrylic acid, and carrying out a stirring reaction so as to obtain a mixture; then adding a CN precursor while heating and stirring, heating to a gel state, and roasting at high temperature to obtain a carbon nitride composite material; dispersing the composite material into water, adding a cobalt chloride solution, carrying out ultrasonic treatment, and adjusting the pH value to 10-11 to obtain a mixture; and adding a NaBH4 solution, reducing to obtain nano particles, filtering, washing and drying to obtain the catalyst. According to the preparation method, the carbon nitride composite carrier with high specific surface area is prepared firstly, then the active component is loaded, and the photocatalytic degradation effect of p-nitrophenol is improved through the synergistic effect of the composite carrier and the active component.

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

The invention discloses a texturing process of a single crystal battery piece. The texturing process comprises the following steps: S1, performing pre-texturing treatment on a silicon wafer by adopting pre-texturing liquid; s2, texturing the silicon wafer by adopting texturing liquid; the prefabricated down liquid comprises polyvinylpyrrolidone and polyvinyl alcohol; the texturing liquid comprises inorganic alkali, a defoaming agent and a catalyst; the inorganic base is selected from at least one of sodium hydroxide and potassium hydroxide, and the defoaming agent is selected from at least one of dodecyl trimethyl ammonium chloride, hexadecyl trimethyl ammonium chloride, octadecyl trimethyl ammonium chloride, diethylene glycol, triethylene glycol and tetraethylene glycol. The catalyst is selected from at least one of sodium 5-nitro-o-methoxyphenolate, sodium o-nitrophenolate and sodium p-nitrophenolate. A nucleating agent solution is adopted to carry out texturing pretreatment on a silicon wafer, then alkali treatment texturing is carried out on the silicon wafer, and the liquid changing period of the texturing process is long; and the cell pieces prepared by taking the polyvinylpyrrolidone and the polyvinyl alcohol as the combined nucleating agent are relatively small in inter-piece color difference.

The invention discloses a method for synthesizing mesalazine and application of mesalazine. The method comprises the following steps: introducing p-nitrophenol, formic acid and a Cu-Co-coated MFI-NS molecular sieve catalyst into a continuous flow reaction zone, and sequentially carrying out electrophilic substitution and nitro hydrogenation cascade reaction at normal pressure and 50-70 DEG C; the catalyst has a micropore-mesopore stepped pore channel, and contains a Cu0 metal cluster and a framework Co < 2 + > acid site. And separating, acidifying and crystallizing the reaction liquid to obtain a finished product. According to the invention, the shape-selective selectivity and difunctional synergistic effect of the molecular sieve are utilized, high conversion rate (gt, 98%) and high selectivity (gt, 94%) under mild conditions are realized, the product purity is greater than or equal to 99.5%, and the Cu / Co residue meets the ICHQ3D standard. The catalyst can be recycled for 10 times or more, the yield is reduced by 5% or less, iron mud pollution of a traditional iron powder method and the metal leaching risk of a noble metal catalyst are thoroughly eliminated, and the method has the remarkable advantages of being environmentally friendly, efficient, low in cost, easy to industrially amplify and the like and is suitable for preparing the medicine for treating the inflammatory bowel disease.

The invention relates to an activity detection method of arabinofuranosidase and application of the activity detection method. The activity detection method comprises the following steps: mixing p-nitrophenyl-alpha-L-arabinofuranosidase with a to-be-detected sample, incubating, adjusting the pH value to 6.5-8 after the reaction is terminated, and determining. According to the method, p-nitrophenyl-alpha-L-arabinofuranosidase is adopted to catalyze p-nitrophenyl-alpha-L-arabinofuranoside to generate p-nitrophenol, p-nitrophenol has a characteristic absorption peak at 410nm, and the activity of the arabinofuranosidase under different dilution multiples can be calculated by measuring a 410nm light absorption value. The optimal enzyme activity of the alpha-L-arabinofuranosidase can be finally calculated by performing parabola fitting on different dilution multiples and enzyme activities. Wherein in a pH range of 6.5-8, p-nitrophenol can have a relatively strong color development effect, and a substrate blank is free of mixed color interference, so that the accuracy of detection by adopting a light absorption value can be remarkably improved.

The invention belongs to the technical field of catalyst technology and nitro-aromatic hydrocarbon selective hydrogenation, and discloses a method for preparing a CuxC-Ni3C-C composite catalyst by a carbonization reduction method and application of the CuxC-Ni3C composite catalyst. According to the preparation method, the CuxC-Ni3C-C composite catalyst is prepared by taking a nickel-copper mixed hydroxide as a precursor, C2H2 / Ar as a carbonization gas and H2 as a reduction gas for the first time, and CuxC promotes low-temperature synthesis of Ni3C. The method is easy and convenient to operate and simple in step. Compared with other methods, the method has the advantages that a high-temperature reaction process is avoided, and CuxC-Ni3C-C particles prepared at a lower temperature are small in size and uniform in distribution. The relatively low preparation temperature prevents particle aggregation and Ni3C high-temperature decomposition, so that the catalytic performance and stability of the catalyst are improved. Compared with catalysts such as CuxC, Ni3C, Cu, Ni and the like, the p-nitrophenol hydrogenation performance of the CuxC-Ni3C composite catalyst is remarkably improved.

The invention relates to the technical field of photocatalysts, in particular to a nonmetal plasmon heterojunction material, a preparation method and application thereof and a method for preparing p-aminophenol through reduction of p-nitrophenol. The nonmetal plasmon heterojunction material provided by the invention comprises a C3N4 nanosheet and a WO3-x nanoplate (x is 0.1 to 0.3) positioned on the surface of the C3N4 nanosheet. The WO3-x local surface plasmon characteristic can effectively expand the spectral response range of the non-metal plasmon heterojunction material in a visible region to a near-infrared region, and the light absorption efficiency of the non-metal plasmon heterojunction material is remarkably enhanced. The nonmetal plasmon heterojunction material provided by the invention can realize efficient reduction of p-nitrophenol based on the synergistic effect of an interface heterojunction, a built-in electric field and oxygen vacancies, is high in selectivity, has excellent photocatalytic activity for reduction of p-nitrophenol, and is excellent in photocatalytic activity stability.

The invention discloses a resin material for 3D printing and a preparation method thereof, and relates to the technical field of photosensitive resin materials. When the resin material for 3D printing is prepared, 3-isocyanate propyl methyl dimethoxy silane is blocked by p-nitrophenol, so that blocked 3-isocyanate propyl methyl dimethoxy silane is prepared; the preparation method comprises the following steps: carrying out condensation on blocked 3-isocyanate group propyl methyl dimethoxy silane, 3-mercaptopropyl methyl dimethoxy silane and hexamethyldisiloxane, so as to prepare blocked isocyanate group mercapto silicone oil; the preparation method comprises the following steps: loading a resorcinol bis (diphenyl phosphate) flame retardant on glass flakes modified by silane to prepare flame-retardant modified glass flakes; the preparation method comprises the following steps: reacting epoxy acrylate, blocked isocyanate sulfydryl silicone oil, acryloyl morpholine and a photoinitiator to prepare photosensitive resin, and compounding the photosensitive resin with flame-retardant modified glass flakes to prepare the resin material for 3D printing. The prepared resin has high mechanical property, flame retardant property and thermal stability.

The present invention belongs to the fields of solid waste resource recovery and high-value utilization, as well as catalytic technology, and particularly relates to a method for preparing a coal gasification slag-based supported NaA zeolite catalyst and its application. The present invention successfully loads metal oxides or elemental metals onto the NaA zeolite through the adsorption of heavy metal ions combined with a calcination treatment. The introduction of the metal active component significantly enhances the catalyst's catalytic performance, demonstrating excellent activity in the catalytic reduction of p-nitrophenol.

A preparation method of a Co@CM multi-channel ceramic catalytic membrane for hydrogenation of p-nitrophenol is provided. In the catalytic membrane, a multi-channel ceramic membrane is adopted as a substrate. A cobalt salt as an active component is loaded in situ on a surface and in pores of the multi-channel ceramic membrane through a forced circulation with the help of the excellent reduction and anchoring effects of dopamine (DA), and then subjected to in situ self-reduction through calcination to produce the Co@CM multi-channel ceramic catalytic membrane. The preparation method has the following advantages: Nano-scale Co particles are loaded instead of a precious metal on a multi-channel ceramic membrane, and the surface of the Co particles is wrapped by carbon and nitrogen, which can effectively inhibit the loss of Co particles during a reaction. In addition, there is no need to add an additional reducing agent during the reduction of Co.

The invention particularly relates to a medium-entropy alloy material, a preparation method thereof, a modified electrode containing the medium-entropy alloy material, an electrochemical sensor containing the medium-entropy alloy material and application. The preparation method of the medium-entropy alloy material comprises the following steps that three metal elementary substance raw materials are mixed according to the molar ratio of 1: 1: 1, the mixture is placed in a vacuum smelting furnace to be smelted, and the medium-entropy alloy material is obtained; the three metal elementary substance raw materials are any three of Ni, Al, Mo, Fe, Cr, Al and Co. The modified electrode comprises a substrate electrode and the medium-entropy alloy material, and the medium-entropy alloy material is modified on the surface of the substrate electrode. The invention also provides application of the modified electrode in an electrochemical sensor and the electrochemical sensor containing the modified electrode. The medium-entropy alloy material shows good catalytic reduction activity on p-nitrophenol, and an electrochemical sensor constructed based on the medium-entropy alloy material is applied to detection of p-nitrophenol, so that a good analysis effect is achieved.

The present invention provides a copper hydrogen nanocluster Cu 20 H9 and its preparation method and catalytic application. The molecular formula of the copper hydrogen nanocluster is [Cu 20 H9Y 10 ]·X, Y are nitrogen ligands after dehydrogenation, and X is an anion. Thus, the copper hydrogen nanocluster has good stability and high catalytic activity, especially for the catalysis of 4-nitrophenol. In some embodiments, the catalytic efficiency of the copper hydrogen nanocluster for 4-nitrophenol can be as high as more than 99%.

The invention belongs to the field of crossing of nano-materials and coordination chemistry, and particularly relates to an Ag19Pd nano-cluster with unsaturated active sites and a preparation method and application of the Ag19Pd nano-cluster. The chemical formula of the nano-cluster is C141H126Ag19Cl3N18P6Pd, the chemical formula is abbreviated as Ag19Pd (dpa) 6 (dppp) 3Cl3, and the nano-cluster belongs to a triclinic system; the nano-cluster has a space group of P-1, # imgabs 0 # alpha = 80.073 (3) degrees, beta = 75.948 (3) degrees, gamma = 88.025 (3) degrees and # imgabs 1 #, and in addition, the nano-cluster has high monodispersity and stability and contains an unsaturated mu3-Ag active site. The Ag19Pd nano-cluster disclosed by the invention has an atomic-scale accurate structure and unsaturated active sites, and shows high catalytic activity in a p-nitrophenol reduction reaction after being formed with commercially available TiO2 to form a supported catalyst, the reaction rate constant is up to 1.26 min <-1 >, and the Ag19Pd nano-cluster has a wide development prospect.

The invention relates to the technical field of pesticide residue detection, in particular to a soil pesticide residue detection method which comprises the following steps: taking a soil sample to be detected, drying and grinding to obtain soil powder; mixing the soil powder with water, MgSO4 and an acetonitrile solution containing 2.5-3.5% of formic acid, carrying out vortex treatment, ultrasonic treatment and centrifugation, then collecting supernate, repeatedly extracting for one time, and then combining the supernate; and filtering the merged supernate by using a filter membrane, and analyzing by using an ultra-high performance liquid chromatography-triple quadrupole tandem mass spectrometry system. According to the method, extraction and chromatography-mass spectrometry conditions are optimized, 25 pesticide residues such as p-nitrophenol, imidacloprid and metabolites thereof can be detected at the same time, and the method has the advantages of being high in extraction efficiency, easy and convenient to operate, high in matrix interference resistance, high in sensitivity, good in accuracy and the like and is suitable for high-throughput detection and analysis of various pesticide residues in soil.

The invention belongs to the technical field of zinc content determination, and particularly relates to a method for determining zinc content by using a precipitation separation EDTA (Ethylene Diamine Tetraacetic Acid) dropping method, which comprises the following steps: S1, putting a sample into a beaker, and adding sodium fluoride, concentrated hydrochloric acid and concentrated nitric acid for dissolving; s2, purging a watch glass and a beaker, and adding water for dilution; s3, adding ammonium chloride, and neutralizing with ammonia water to precipitate; s4, adding anhydrous sodium sulfite, heating to slightly boil, and filtering with filter paper; s5, washing the beaker and the precipitate with an ammonium chloride washing solution, adding p-nitrophenol, and adjusting to be colorless; s6, adding an acetic acid-sodium acetate buffer solution, adding sodium fluoride and ascorbic acid, and uniformly mixing; s7, dropwise adding an indicator, and titrating with an EDTA standard solution; and S8, calculating. According to the method, one-step efficient separation of lead, iron and aluminum can be achieved, interference of lead residues on zinc determination is reduced, interference of coexisting ions is eliminated, and errors are obviously reduced.

The invention relates to the technical field of catalyst preparation, and particularly discloses a preparation method of a nano-catalyst for p-nitrophenol reduction reaction, and the preparation method specifically comprises the following steps: S1, preparation of MoS2: S101, adding 1 mmol of ammonium heptamolybdate and 30 mmol of thiourea into 40 mL of deionized water, and magnetically stirring for 30 minutes; s102, pouring the stirred transparent solution into a stainless steel polytetrafluoroethylene lined autoclave, and heating at 200 DEG C for 12 hours; s103, centrifuging the obtained sample, washing with pure water and ethanol, and drying at 80 DEG C for 8 hours to obtain MoS2; s2, preparation of CoMoS2: S201, adding 1 mmol of a mixture containing ammonium heptamolybdate and cobalt chloride hexahydrate and 30 mmol of thiourea into 40 mL of deionized water, and carrying out magnetic stirring for 30 minutes; in the invention, the synthesized Au / CoMoS2 catalyst shows excellent catalytic activity, and the reaction treatment time is short.