95 results about "Molar concentration" patented technology

A gas separation method includes supplying a mixed gas to a zeolite membrane complex and permeating a high permeability gas through the zeolite membrane complex to separate the high permeability gas from other gases. The mixed gas includes a high permeability gas and a trace gas that is lower in concentration than the high permeability gas. The molar concentration of a first gas included in the trace gas in the mixed gas is higher than the molar concentration of a second gas included in the trace gas in the mixed gas. The adsorption equilibrium constant of the first gas on the zeolite membrane is less than 60 times that of the high permeability gas. The adsorption equilibrium constant of the second gas on the zeolite membrane is 400 times or more that of the high permeability gas.

The invention provides a method for detecting PFAS based on a three-dimensional Ag / NiFe-LDHs surface enhanced Raman scattering substrate and ion pair extraction, and belongs to the technical field of PFAS detection.The method comprises the steps that firstly, the three-dimensional Ag / NiFe-LDHs SERS substrate is prepared, then ion pair extraction-dissociation treatment is conducted on a water sample to be detected, a detection solution is obtained, finally, the substrate is immersed in the detection solution for adsorption, and finally the detection solution is obtained. A spectrum is collected through a Raman spectrometer, and semi-quantitative detection of PFAS in a water sample is achieved according to the linear relation between the characteristic peak intensity and the PFAS molar concentration logarithm. According to the method, collaborative application of the three-dimensional Ag / NiFe-LDHs SERS substrate and an ion pair extraction technology and indirect detection of PFAS are realized, the detection difficulty that PFAS Raman signals are weak and are difficult to enrich is improved, the detection sensitivity and adaptability of PFAS in a water sample are improved, and an application foundation is laid for rapid monitoring of PFAS pollution of an environmental water body.

The invention is suitable for the application field of electrolyte acidity determination, and provides a method for determining the acidity of an all-vanadium electrolyte based on a complexing mass difference method, and the method comprises the following steps: taking the all-vanadium electrolyte, and diluting the all-vanadium electrolyte into a pretreated all-vanadium electrolyte with the concentration of 0.05-0.1 mol / L; adding 1.5-2mL of a complexing masking reagent with the molar concentration of 1.5-2mol / L, weighing, and recording as M1; stirring and titrating, weighing and recording as M2; a quantitative determination method of mass difference is used for calculation, and the formula is {(M2-M1)-0.05} / A * C. In conclusion, a mass difference quantitative determination method is adopted, the vanadium complexing masking reagent is added, the adding amount and the pH value of the vanadium complexing masking reagent are controlled, a stable complex is formed through the complexing masking reagent, vanadium ions and impurity ions, the oxidation-reduction reaction and the precipitation reaction of the complex and sodium hydroxide are inhibited, and the accuracy of the acidity value of the all-vanadium electrolyte is improved.

A gas separation method includes supplying a mixed gas to a zeolite membrane complex and permeating a high permeability gas through the zeolite membrane complex to separate the high permeability gas from other gases. The mixed gas includes a high permeability gas and a trace gas that is lower in concentration than the high permeability gas. The trace gas contains an organic substance whose molar concentration in the mixed gas is higher than or equal to 1.0 mol %. The adsorption equilibrium constant of the organic substance on the zeolite membrane is less than 150 times the adsorption equilibrium constant of the high permeability gas.

The invention discloses a method for measuring the molar concentration of nano-particles. The method comprises the following steps: diluting a nano-particle suspension with a high-molecular polymer solution or dispersing nano-particle powder into the high-molecular polymer solution; transferring the suspension liquid to a spacing net on the side of a sample pool in an electrophoresis tank; nano-particles migrate from the sample pool to the buffer pool under the driving of the electric field and are uniformly distributed on the spacing net in a single-particle manner; performing single-particle imaging on the spacing net by using an optical microscope; and counting the number of the nanoparticles in the image so as to measure the molar concentration of the nanoparticles in the sample. The method can be used under the condition that the properties of the nanoparticles are unknown or no standard substance exists, the detection object has no additional condition, and the accuracy is high.

The present solution provides a hybrid coagulant based on aluminum-iron silicate, where the molar concentration of silicon is in the range of 0.1 to 0.5 mol∙l-1, the molar ratio of the sum of aluminum and iron to silicon is in the range of 1:0.5 to 1:1.5, the molar ratio of aluminum to iron is in the range of 0.5:1 to 5:1, and a method of its preparation by mixing hydrated aluminum sulfate, hydrated iron sulfate and an acidic solution of silicon dioxide.

The invention discloses celeste glaze fired in a non-reducing atmosphere and a preparation method of the celeste glaze. The celeste glaze provided by the invention is prepared from the following raw materials in percentage by mass: 56 to 60 percent of feldspar, 15 to 18 percent of quartz, 10 to 13 percent of calcite, 1 to 3 percent of talc, 5 to 8 percent of kaolin and 6 to 8 percent of celadon pigment. The main crystalline phase of the celadon pigment is zirconium silicate, vanadium ions and iron ions playing a coloring role are wrapped outside the zirconium silicate, the molar concentration of the vanadium ions is 2%-4%, and the molar concentration of the iron ions is 1%-3%. According to the method, the vanadium iron ion celadon pigment wrapped by the high-temperature pre-stabilized zirconium silicate is used as the coloring agent, and the celeste blue glazed porcelain is fired in the non-reducing atmosphere, so that the core problem existing in the traditional firing in the reducing atmosphere is successfully solved. And ferrovanadium ions in the coloring agent are stably wrapped in zirconium silicate crystals and are not influenced by the fluctuation of the firing atmosphere, so that the consistency of the glaze color of the same batch of celeste glaze is ensured. Regulation and control of the celeste glaze color are achieved through the adding amount of the celadon pigment, operation is easy, convenient and visual, and dependence on technical experience of operators is reduced.

The invention discloses a universal sample type nucleic acid releasing agent and application thereof. The nucleic acid releasing agent is prepared from the following components in molar concentration: 20 to 100 mM of Tris-HCl, 30 to 500 mM of sodium chloride, 30 to 200 mM of ammonium sulfate, 1 to 6 mM of EDTA (Ethylene Diamine Tetraacetic Acid), 1 to 8 mM of a reducing agent, 0.1 to 0.2 percent of sodium dodecyl sarcosinate, 0.1 to 3 mM of Surfactin, 5 to 30 percent of Chelex-100 and 5 to 15 percent of trehalose. According to the method, various samples can be mildly split, impurities such as impure proteins and lipids can be effectively removed, the complexity of nucleic acid samples is reduced, and the method is seamlessly jointed with subsequent PCR (Polymerase Chain Reaction); the kit has double effects of sample preservation and splitting decomposition, can strongly inhibit various nuclease, and can ensure the long-term storage stability of samples.

The invention relates to the field of chemical analysis and detection, in particular to a method for rapidly detecting the concentration of industrial concentrated acid based on neutralization reaction, which comprises the following steps: 1, theoretical calculation; converting molar concentration according to acid density and mass fraction; 2, accurately measuring the volume of target acid by using a pipette; 2, injecting 100-150ml of pure water into the triangular flask, and adding 3-5 drops of phenolphthalein; 3, slowly injecting an acid sample into the triangular flask, and slightly shaking and uniformly mixing; 4, adding 10.00 ml of NaOH solution by using the pipette, and oscillating for 10-20 seconds; 3, result interpretation: transparency and colorless: acid is excessive when the acid concentration reaches the standard, pH is less than or equal to 8.2 after neutralization, pink lasts for 20-30 seconds, and reinspection is needed when the acid concentration is insufficient and the pH is greater than or equal to 8.3. The method has the beneficial effects that 1, a reverse judgment method is adopted, namely the conventional end-point titration is replaced by fixed alkali amount, so that the detection time is shortened to 2 minutes; 2, safety design: pre-dilution reduces the risk of acid mist, and only a trace amount of raw acid is needed to avoid acid corrosion; 3, multi-acid adaptation: compatibility with detection of different types of concentrated acids is realized through pipetting volume adjustment;

The invention discloses a norfloxacin-europium sensor array for identifying physiological phosphate and monitoring ATP (adenosine triphosphate) hydrolysis as well as a preparation method and application of the norfloxacin-europium sensor array. The sensor array comprises at least two sensing units with different norfloxacin-europium ion molar concentration ratios, the sensing unit is obtained by mixing and self-assembling a norfloxacin solution and a europium ion solution. Based on direct self-assembly of cheap norfloxacin (NF) and Eu < 3 + > ions, five physiologically crucial phosphates can be effectively distinguished, and ATP hydrolysis can be monitored. By adjusting the concentration of Eu < 3 + >, a multiple recognition mechanism is established, and target PPs can be completely distinguished with the accuracy of 100%.

The application provides a method for detecting PFAS based on a three-dimensional Ag / NiFe-LDHs surface enhanced Raman scattering substrate and ion pair extraction, and belongs to the technical field of PFAS detection, and comprises the following steps: first, a three-dimensional Ag / NiFe-LDHs SERS substrate is prepared; then, ion pair extraction-dissociation treatment is performed on a water sample to be measured to obtain a detection solution; finally, the substrate is immersed in the detection solution for adsorption, a spectrum is collected by using a Raman spectrometer, and semi-quantitative detection of PFAS in the water sample is realized according to the linear relationship between the characteristic peak intensity and the logarithm of the molar concentration of PFAS. The application realizes the synergistic application of the three-dimensional Ag / NiFe-LDHs SERS substrate and the ion pair extraction technology and the indirect detection of PFAS, improves the detection difficulty of weak PFAS Raman signals and difficult enrichment, improves the detection sensitivity and adaptability of PFAS in the water sample, and lays an application foundation for rapid monitoring of PFAS pollution in environmental water.

A method for separating an amine, said method comprising a separation step for separating an amine by chromatography using a stationary phase containing an oligosaccharide, a polysaccharide, and / or a derivative thereof, and a mobile phase containing one or more specific acids selected from the group consisting of oxalic acid, acetic acid, formic acid, and trifluoroacetic acid, one or more bases, and a solvent; when A is the value calculated by the following formula (1) for each specific acid contained in the mobile phase, SA is the total value of each A calculated by each specific acid, B is the value calculated by the following formula (2) for each base contained in the mobile phase, and SB is the total value of each B calculated by each base, SB / SA is 0.05-0.95. Formula (1): A = the number of elements of the specific acid * the molar concentration (mol / L) of the specific acid Formula (2): B = the number of elements of the base * the molar concentration (mol / L) of the base.

The purpose of the present invention is to maintain the activity of an enzyme while reducing proliferation of microorganisms that cause food deterioration in a state where the enzyme is dissolved in water. The present invention provides a food composition that satisfies all of the following requirements (a)-(d). (a) The moisture content in terms of wet mass is 20 mass% or more. (b) The pH at 20°C and 1 atm is more than 4.0. (c) The titratable acidity of the food composition when measured by a measurement method A is 0.1 mass% or more. Measurement method A 10 g of the food composition is accurately collected and diluted 10-fold with ion-exchanged water, 0.08 ml of a 3.1% phenolphthalein solution serving as an indicator is added to the diluted solution (100 g), the resulting solution is neutralized by titration with a 0.1 mol / L sodium hydroxide liquid having a known titer, and the titratable acidity is determined by the following formula.　Titratable acidity (mass%) of food composition={(60.05×0.1×F×V)×100} / {collection quantity (10 g)×1000} 60.05: Molecular weight of acetic acid 0.1: Molar concentration (mol / L) of sodium hydroxide solution F: Titer of 0.1 mol / L sodium hydroxide solution V: Titration amount (mL) of 0.1 mol / L sodium hydroxide (d) The following requirements (i) and / or (ii) are satisfied. Requirement (i) The following formula is satisfied: 4Y+X≥10 (provided that X≥3 and Y>0.03 are satisfied), where X g represents the amount of sodium chloride equivalent per 100 g of water of the food composition, and Y g represents the content of non-dissociated acetic acid per 100 g of water of the food composition. Requirement (ii) The amount of sodium chloride equivalent per 100 g of water of the food composition is 3.0 g or more, and the ethanol content per 100 g of water of the food composition is 8.0 g or more.

The application relates to a method for preparing micron-grade spherical or spheroidal Cu powder in an aqueous phase, which comprises the following steps: weighing a certain amount of copper sulfate and polydiallyldimethylammonium chloride, adding the copper sulfate and the polydiallyldimethylammonium chloride into a certain volume of water, stirring and dissolving to obtain solution A; the molar concentrations of the copper sulfate and the polydiallyldimethylammonium chloride in the solution A are 30-80 mmol / L and 100-300 mmol / L respectively; weighing a certain amount of a reducing agent N,N-diethylhydroxylamine, adding the reducing agent into a certain volume of water, stirring and dissolving to obtain solution B; mixing the solution A and the solution B, stirring at a certain rotating speed at a temperature of 70-95 DEG C for 4h; then centrifugal separation, washing and vacuum drying to obtain micron-grade Cu powder. The micron-grade Cu powder prepared by the application is spherical or spheroidal, has good dispersibility, uniform particle size distribution, adjustable particle size in the range of 1.0-5.0 mu m, narrow particle size distribution range, uniform morphology, high crystallinity, and is beneficial to further preparation of Ag-coated Cu powder (Cu@Ag).

The invention relates to the technical field of small-molecule contrast agents, in particular to a small-molecule contrast agent and a preparation method thereof. According to the micromolecule contrast agent provided by the invention, a divalent glycosyl group is introduced into a binary triiodo-benzene ring structure, so that each molecule contains six iodine atoms (the theoretical iodine content reaches 48.7 wt%), the molecular weight is controlled to be 2000Da or below, the water solubility is remarkably improved, the viscosity is reduced, and the performance is superior to that of a traditional contrast agent. Preliminary CT imaging experiments show that under the same molar concentration, the average CT value generated by the contrast agent YJY-86-2 is obviously higher than that generated by iohexol, and the contrast agent shows stronger imaging contrast ability. The characteristic is expected to realize better image quality while reducing the dosage of administration and reducing the risk of iodine exposure, and provides a powerful candidate material for realizing high-sensitivity detection of early tumors.

The application provides a method for analyzing nickel in a zinc-nickel electroplating solution. The method comprises: performing standard coulometric titration on a sodium thiosulfate standard solution to calculate an actual molar concentration c 标准 ; adding an oxidizing agent solution and a sodium hydroxide solution to the zinc-nickel electroplating solution to obtain a high-nickel hydroxide precipitate, then adding a KI solution and sulfuric acid to obtain a sample solution; adding a second part of the sodium thiosulfate standard solution and a second part of a KI electrolyte to an electrolytic cup to perform sample coulometric titration and calculate the molar concentration c 镍 of nickel in the zinc-nickel electroplating solution. The application uses the change in the valence state of nickel hydroxide, combines a redox reaction with an indirect coulometric titration method, and obtains a cyanide-free coulometric titration method for quantitatively determining the content of nickel in a zinc-nickel electroplating solution. The method does not need to prepare a standard solution, indirectly determines nickel by using electrically generated iodine in a high-concentration zinc metal ion background, realizes high selectivity, high precision, and online determination of the content of nickel, and can significantly improve the detection efficiency.

The present application relates to a kind of soil salt data correction method, device, storage medium and electronic equipment, comprising: calculating soil parameter based on the soil salt data obtained by soil sample test;Reliable sample meeting the condition of soil parameter is selected, first prediction model based on the total charge equivalent predicted by extract solution conductivity is constructed, and second prediction model based on the cation charge equivalent to predict extract solution conductivity;Total charge equivalent prediction value of deviating sample is obtained using first prediction model;The salt type of deviating sample and maximum allowable absolute deviation are determined;Based on soil salt data and total charge equivalent prediction value, the soil salt prediction content of deviating sample is obtained, based on salt content and soil salt prediction content, the salt deviation of deviating sample is obtained;Determine ion adjustment strategy based on soil parameter, adjust the molar concentration in the soil salt data of deviating sample according to ion adjustment strategy, second prediction model.It can improve the reliability of soil salt data.

The invention discloses a method for preparing elemental selenium and copper in one step, and belongs to the field of electrochemical deposition. The method comprises the following steps: dissolving cuprous selenide in a deep-eutectic solvent to obtain an electrochemical deposition solution, wherein the molar concentration of chloride ions in the deep-eutectic solvent is not lower than 35%; and performing electrochemical deposition in an electrochemical deposition solution by taking inert electrodes as a cathode and an anode, depositing elemental copper on the anode, and depositing elemental selenium on the cathode. According to the method, elemental selenium and copper can be prepared at the same time, the problems of high energy consumption, large pollutant emission and the like of a traditional process are effectively solved by adopting the eutectic solvent, and the method is a sustainable and short-flow process.

The invention belongs to the technical field of steel surface modification, and particularly relates to modification treatment liquid for preparing a steel-based super-hydrophobic surface through a chemical deposition method and preparation and application methods of the modification treatment liquid. The molar concentration of the deposition agent in the treating fluid is 0.01-0.1 mol / L; the molar concentration of the modifier in the treating fluid is 0.01-0.1 mol / L; the deposition agent is an inorganic salt, the modifier is a fatty acid organic low-surface-energy substance, and the solvent is a mixture of water and an organic solvent. The method has the advantages that in-situ construction of the micro-nano rough structure on the steel surface and synchronous modification of the low-surface-energy substance are achieved in one step. And the super-hydrophobic surface can be formed only by soaking the steel material, so that the production efficiency is improved, and the equipment investment and energy consumption cost are reduced. The treating fluid can endow common steel and iron materials with super-hydrophobic characteristics, the static contact angle of the obtained surface can reach 150 degrees or above, and the treating fluid has excellent waterproof, anti-icing, anti-fouling and anti-corrosion performance.

The composition for chemical conversion treatment according to one embodiment of the present invention contains a trivalent chromium-containing substance, an organic sulfur compound, an organic phosphonic acid compound, a vanadium-containing substance, and a hydroxycarboxylic acid-containing substance, and thus can form a chemical conversion coating film having both a black appearance and high corrosion resistance even if the cumulative treatment area is increased under quantitative supply management. In the composition for chemical conversion treatment, the ratio of the molar concentration of the vanadium-containing substance in terms of vanadium to the molar concentration of the hydroxycarboxylic acid-containing substance in terms of hydroxycarboxylic acid may be 1: 1-1: 10.

The application discloses a method for obtaining C / C composite ablation morphology based on physical information neural network, and relates to the field of aerospace, comprising the following steps: taking the coordinate data of a C / C composite three-dimensional space model under a Cartesian coordinate system, an ablation time, a dimensionless parameter Sh and a dimensionless parameter A as inputs of a pre-trained multilayer perceptron network, outputting oxygen molar concentration and solid volume fraction through the pre-trained multilayer perceptron network; solving a gas phase diffusion equation and a solid phase evolution equation through the oxygen molar concentration and the solid volume fraction output by the multilayer perceptron network to obtain the C / C composite ablation morphology. The method can efficiently and accurately solve the gas-solid coupling equation, overcome the limitations of traditional numerical methods, accurately obtain the ablation morphology of the C / C composite under the gas-solid coupling effect at a low calculation cost, and provide strong theoretical support and technical support for the application of the C / C composite in the field of aerospace and the like.

This invention discloses a 89 SrCl2 solution 90 Mass spectrometry methods for measuring Sr activity concentration include: obtaining the concentration calculated during mass spectrometry measurement. 90 The formula required for the molar concentration of Sr is to use D in equation (12). F90 D E D was obtained by mass spectrometry; the analyte was calculated using equation (12). 89 SrCl2 solution 90 The molar concentration of Sr is then calculated. 90 The mass concentration of Sr; according to 90 Calculation of Sr mass concentration 90 The activity concentration of Sr; this invention eliminates the need for strontium and yttrium separation, simplifying the operation process, reducing personnel radiation exposure, and allowing direct calculation based on measurement data. 90 Sr activity concentration eliminates the intermediate strontium and yttrium activity concentration conversion process, avoiding 90 The impact of Y recovery rate on the final measurement results.

The application provides a method for determining the zinc content in a zinc-nickel plating solution. The method comprises: adding a first potassium ferricyanide-sulfuric acid supporting electrolyte and a first zinc standard solution into an electrolytic cup, performing first coulometric titration, and obtaining the actual determination time t of the standard solution 标 ; adding a second potassium ferricyanide-sulfuric acid supporting electrolyte, a second zinc standard solution and a pretreated sample into the electrolytic cup, performing second coulometric titration, and obtaining the actual determination time t of the sample to be measured 样 ; then calculating the zinc molar concentration c in the zinc-nickel plating solution by using formula (I) and formula (II) 样 The application establishes a coulometric titration analysis method for zinc ions in a zinc-nickel plating solution. [Fe(CN)6] 4‑ is generated by electrolysis, and a quantitative precipitation reaction of [Fe(CN)6] 2+ and Zn is utilized. The improved standard addition method based on a zinc standard solution can quickly, accurately and on-line determine the zinc content in an alkaline zinc-nickel plating solution.

The invention provides a preparation method of superfine barium sulfate, which comprises the following steps: at room temperature, weighing a proper amount of industrial-grade barium chloride and a proper amount of industrial-grade sodium sulfate solid, adding water to prepare feed liquid with equal molar concentration, filtering impurities, and respectively filling the feed liquid into storage tanks; adjusting the flow rate of the diaphragm metering pump to 2.25-500L / h, then adjusting the two feed liquids to the same stable flow rate, so that the two feed liquids flow out of the storage tank at a set flow rate, enabling the two feed liquids flowing out of the storage tank to simultaneously enter a spherical exhaust pipe, carrying out rapid precipitation reaction to generate an emulsion containing superfine barium sulfate particles, enabling the emulsion to enter a product storage tank, and placing the emulsion in the product storage tank, and finally, centrifugally filtering the emulsion, washing with water, and centrifugally filtering again to obtain a superfine barium sulfate filter cake, thereby finishing the preparation. The small-size effect is utilized, the barium chloride feed liquid and the sodium sulfate feed liquid are rapidly and fully mixed in the spherical exhaust pipe, mixing and mass transfer between fluids are enhanced, and industrial preparation of superfine barium sulfate is facilitated.

Provided is a polishing agent which maintains the polishing speed of a silicon oxide film, achieves a high selectivity between the silicon oxide film and a barrier film, and has excellent storage stability. The polishing agent includes abrasive grains, an anionic polymer, an acidic compound selected from a phosphoric acid compound and an organic acid compound, and water, the anionic polymer being a copolymer including a hydrophobic monomer and an anionic monomer, the anionic polymer having an acid value of 20-400 mgKOH / g, the hydrophobic monomer having a partition coefficient of 0-4, and the anionic monomer having a partition coefficient of 0-4. The anionic monomer contains at least one selected from the group consisting of unsaturated monocarboxylic acids and salts thereof, and when the acidic compound having the highest molar concentration among the acidic compounds is defined as a first acidic compound, the pKa of the first acidic compound and the pH of the polishing agent satisfy the relationship represented by formula (1). | pKa-pH | < = 1.5 (1)

The invention discloses a water-based treatment agent for improving the plastic processing performance of a metal surface, which comprises: a colloidal dispersion liquid containing alumina particles, the content of which is 0.05-0.5 mol / L based on the molar concentration of aluminum element; the content of the alkyl sulfate surfactant is 0.003 mol / L to 0.02 mol / L according to the molar concentration of the sulfur element; the molar concentration of the oxidizing agent ranges from 0.02 mol / L to 0.2 mol / L; the content of the thiocarbamic acid derivative is 0.03 mol / L to 0.2 mol / L according to the molar concentration of the sulfur element; the content of the inorganic acid is 0.00001 mol / L to 0.01 mol / L according to the molar concentration of hydrogen ions. The invention further discloses a using method of the water-based treating agent. The using method comprises the following steps: coating the water-based treating agent on the surface of a metal plate; and drying to form a film so as to form the nano coating on the surface of the metal plate.

This invention discloses a water-based treatment agent for improving the corrosion resistance of carbon steel surfaces, comprising the following active ingredients: a compound containing zincate ions, wherein the molar concentration of zincate ions is 0.02–0.6 mol / L; a nonionic polyol surfactant, the content of which is 0.05–0.8 mol / L based on the molar concentration of hydroxyl groups; a metal ion compound, wherein the molar concentration of metal ions is 0.003–0.1 mol / L; the standard electrode potential of the metal ions is in the range of -0.28V to +0.42V; and an inorganic alkali, the content of which is 0.001–0.1 mol / L based on the molar concentration of hydroxide ions. This invention also discloses a carbon steel substrate comprising a carbon steel substrate and a nanoscale coating formed by coating or depositing the aforementioned water-based treatment agent on the surface of the carbon steel substrate.

A kind of stable method for ion chromatography direct detection of sulfurous acid radical in water belongs to the field of environmental science and technology.The method is as follows: a certain mass of KOH and citrate is placed in water to prepare a mixed concentrated solution, wherein the molar concentration ratio of KOH to citrate is in the range of 1:1 to 4; a certain volume of water sample containing sulfurous acid radical is taken and added to the above concentrated solution and mixed quickly; the mixing ratio is determined according to the concentration of sulfurous acid radical in the water sample, and the mixed solution is used for ion chromatography determination.The present application establishes a sulfurous acid radical ion chromatography determination method using safe and green citrate as stabilizer, citrate is used as stabilizer in alkaline solution to stabilize sulfurous acid radical in sample, and ion chromatography is used to directly determine sulfurous acid radical ions in water, solving the problem of instability of sulfurous acid radical in water during the whole process of sampling, preservation, transportation and determination.

The application relates to the field of membrane separation technology, in particular to a MOF membrane and a preparation method and application thereof. The preparation method comprises the following steps: uniformly mixing an organic ligand, a metal salt and a solvent to obtain a synthesis solution; in the synthesis solution, the molar concentration of the organic ligand is C L , the molar concentration of the metal salt is C M , C L and C M satisfy the following relationship: C L / C M >=10, C L *C M >=0.01; a substrate is taken and immersed into the synthesis solution, and a MOF membrane is formed on the substrate under the condition of a temperature T (unit: DEG C) and a pressure P (unit: bar) for a period of time; wherein 20<=T<=40 and 0.8<=P<=1.2. According to the application, the organic ligand and the metal salt are dissolved in the solvent at a specific proportion, so that the MOF membrane can be prepared quickly under normal temperature and pressure, the problem of harsh preparation conditions of the existing MOF membrane can be solved, and the obtained MOF membrane has good gas permeability and high propylene / propane separation selectivity.

The present invention relates to compositions, and in particular to pharmaceutical compositions, comprising, or even consisting of, a suspension of bacteriophages of the class Caudoviricetes, the bacteriophages having lytic activity against at least one Gram-positive bacterial strain, at a titer of at least 108 PFU / mL, in a dispersing medium comprising, or even consisting of: - at least one non-ionic surfactant, and in particular a single non-ionic surfactant, selected from the polysorbate family, at a molar concentration greater than its critical micelle concentration, but not exceeding 2 mg / mL, and / or the poloxamer family, at a concentration ranging from 0.005% (w / v) to 30% (w / v); - one or more neutral salts formed from a pair of monovalent ions, the total molar concentration of which is in the range from 75 to 160 mM; - a buffer mixture imparting to the composition a pH from 6.0 to 7.9, and preferentially from 7.0 to 7.5, typically selected from hydrogen phosphate ion / dihydrogen phosphate, citric acid / citrate ion and citric acid / hydrogen phosphate ion ion pairs, wherein the molarity of the buffer mixture is in the range from 4 mM to 100 mM; - water, wherein the composition comprises less than 0.9 bacterial endotoxin units per mL and a total protein concentration of less than 0.09 mg / mL, and wherein the bacteriophage suspension in the dispersing medium has an osmolality of between 150 mOsm / kg and 600 mOsm / kg; the invention also relates to associated methods and uses.