109 results about "Phenolphtaleine" patented technology

The invention relates to the technical field of titration detection in analytical chemistry, in particular to a thymol phenolphthalein-TBPE composite indicated cyanide high-precision detection method which comprises the following steps: step 1, after a water sample to be detected is distilled and separated, adjusting the pH value of distillate to a strong alkaline environment required by thymol phenolphthalein color development; 2, adding a composite indicator containing thymol phenolphthalein and tetrabromo phenolphthalein ethyl ester, wherein the mass ratio of the two components in the composite indicator is determined through a color change sensitivity optimization experiment; step 3, titrating with a silver nitrate solution, and judging an end point according to three-order color mutation: the initial state is light yellow, the intermediate state is green, and the end point state is purple red; and 4, adding an auxiliary masking agent before titration, and blocking the reaction between the auxiliary masking agent and silver ions by preferentially complexing interference ions. By optimizing the ratio of the composite indicator and using the masking agent, interference of other substances can be effectively prevented, and accurate detection of cyanide is ensured.

The invention discloses a phenolphthalein-based polyaryletherketone polymer and a preparation method thereof, and the phenolphthalein-based polyaryletherketone polymer is prepared from the following raw materials: 240 to 370 parts of phenolphthalein monomer, 45 to 150 parts of modified phenolphthalein, 140 to 220 parts of 2, 6-dichlorobenzonitrile and 3 to 12 parts of alkyl halide. The modified phenolphthalein is prepared from phenolphthalein and a modifier; the modifying agent is selected from at least one of 3-amino propyl trimethoxy silane, 3-amino propyl triethoxy silane, bis (aminopropyl) polydimethylsiloxane, and aminopropyl terminated polydimethylsiloxane. By introducing a siloxane side chain and a cyano side bond and using long-chain aliphatic hydrocarbon for end capping, the bonding capacity of the polymer and other materials is improved, and meanwhile, the high temperature resistance and toughness of the polymer are kept.

The invention discloses modified epoxy resin suitable for oven forming and a preparation method and application thereof, and belongs to the technical field of resin-based composite materials. The modified epoxy resin comprises the following raw materials in parts by mass: 45-60 parts of bisphenol A epoxy resin; 10 to 15 parts of glycidyl amine tetrafunctional epoxy resin; 15 to 20 parts of glycidyl ester type trifunctional epoxy resin; 10 to 16 parts of a toughening agent; 40 to 45 parts of 4, 4 '-diaminodiphenyl sulfone; the toughening agent is thermoplastic phenolphthalein polyaryletherketone resin or thermoplastic phenolphthalein polyethersulfone resin, and the obtained modified epoxy resin has similar viscosity-temperature characteristics, highest exothermic temperature and relatively long gelation time as MTM45-1 oven molding resin applied in airbus certification, and is suitable for being used in preparation of oven molding prepregs. And the obtained oven molded prepreg has good stability, and the difference of products in each batch is small.

The invention relates to the technical field of environmental analytical chemistry, and discloses a thymol phenolphthalein-TBPE double indicator-based cyanide titration detection method and system, and the method comprises the following steps: adjusting a water sample to be detected to an alkaline pH interval to construct a detection matrix; the method comprises the following steps: introducing a double-indicator system composed of thymol phenolphthalein and tetrabromo phenolphthalein ethyl ester according to a specific ratio into a detection matrix, and constructing a spectrum background for masking yellow interference of sulfide by utilizing the blue color development characteristic of thymol phenolphthalein; dropwise adding a silver nitrate standard solution into the mixed system to execute a complex reaction; according to the method, a spectrum background shielding field is constructed, chromaticity response of a system in a specific wave band is monitored in real time, and when a chromaticity mutation signal from green to bluish violet is captured, a titration end point is judged, and the cyanide concentration is calculated. High-precision anti-interference detection on cyanide in a complex high-turbidity matrix is realized, and the sensitivity and accuracy of end point recognition are improved.

To bring an indication material into close adhesion to a concrete hole wall surface in a press-contact state to promote a color reaction of a phenolphthalein agent, thereby improving measurement accuracy.SOLUTION: A method for measuring the depth of neutralization of a concrete structure includes: inserting, into a bore 12, an indication material 1 that is a base material sheet 2 with an elongated shape carrying a phenolphthalein agent-containing layer 3 on its front side; inserting, into a bore space on a rear face of the indication material 1, an elastic tube 6 expandable in a radial direction by a fed fluid; feeding air into the elastic tube 6 to expand the elastic tube 6 in the radial direction, and pressing the indication material 1 against a hole wall surface from the rear face side to bring them into close adhesion in a press-contact state, thereby promoting a color reaction of a phenolphthalein agent; and after the lapse of a predetermined time, removing the fluid from the elastic tube 6 to shrink the elastic tube and drawing out the elastic tube from the bore 12, and pulling out the indication material 1 from the bore 12 and measuring the distance from a concrete opening end corresponding position of the indication material 1 to a coloration region, thereby measuring the depth of neutralization.SELECTED DRAWING: Figure 5

The present invention belongs to the technical field of chemical raw material preparation, and particularly relates to a preparation method of 3,3'-diaminophenolphthalein. The method includes: mixing 3,3'-dinitrophenolphthalein, Pd / C catalyst and tetrahydrofuran, and performing a hydrogenation reaction to obtain a reaction solution containing 3,3'-diaminophenolphthalein. The preparation method has a simple reaction process, low requirements for the reaction device, does not require high temperature, has mild conditions, short reaction time, reduces the risk of the hydrogenation reduction reaction, and is suitable for large-scale production; moreover, there are no reaction by-products, and high-purity products can be directly obtained through sedimentation, filtration and drying, with a high product yield of over 85% and a purity of over 99%.

This invention discloses a high-modulus, high-toughness bismaleimide resin composition, a carbon fiber prepreg, and a preparation method thereof, belonging to the field of composite material technology. The bismaleimide resin composition of this invention comprises the following raw materials in parts by weight: 40-80 parts bismaleimide resin, 10-20 parts o-diallyl bisphenol A, and 5-10 parts a powder toughening agent containing phenolphthalein side chains. The carbon fiber prepreg of this invention is made from the above resin composition and carbon fibers, with thermoplastic polyimide felt interlayered to form an integrated structure. This allows the composite material prepared from the carbon fiber prepreg to maintain high modulus and high temperature resistance while significantly improving its toughness, impact damage tolerance, and interlayer delamination resistance. Furthermore, the prepreg of this invention has good processability and is suitable for manufacturing high-performance complex components.

The invention discloses a rapid detection and on-site treatment method for ammonia and black oil in fly ash, which comprises the following steps: 1) weighing 200g of fly ash from the batch of fly ash, putting the fly ash into a conical flask, adding 80g-90g of water for stirring, and stirring; (2) after stirring is completed, covering a conical bottle opening with test paper soaked with a 1% phenolphthalein alcohol solution; 3) if the test paper turns red, determining that ammonia with relatively high content exists; 4) standing for 8-10 minutes, and observing whether black oil exists on the surface of the neat paste; 5) after the detection is completed, treating excessive ammonia and black oil in the fly ash; according to the present invention, the ammonia content is rapidly detected by using the test paper impregnated with the 1% phenolphthalein alcohol solution, the black oil is observed by standing, and the concrete stirring and vibrating process is combined so as to achieve the real-time determination and the emergency treatment of the fly ash pollutants, such that the concrete structure quality is improved, and the fly ash field detection method is supplemented.

The invention relates to the technical field of concrete detection, in particular to an instrument for detecting concrete carbonization depth by using an imaging technology. According to the technical scheme, the device comprises a box body, a first cavity and a second cavity are formed in one side of the box body, holes of the specified size are punched in the wall face through a punching assembly, then residual concrete chippings in the holes are blown away through a cleaning assembly, the interiors of the holes are kept clean and tidy, then a phenolphthalein alcohol solution is added into a storage frame, and the phenolphthalein alcohol solution is stored in the storage frame; the phenolphthalein alcohol solution is sprayed into the hole through the spraying assembly, the color of the concrete contaminated with the phenolphthalein alcohol solution can be changed due to different pH values, so that the color of the uncarbonized concrete is changed, then the detection assembly extends into the hole, and the color-changing part in the hole is detected by utilizing an imaging technology; and digital images and depth data are obtained and are convenient to analyze and store, so that the problem of detection result deviation easily caused by sight obstruction during detection is solved.

The utility model discloses a simple device for detecting the ammonia removal effect of a fabric, which relates to the field of functional textile effect detection devices and comprises a detection body, a first liquid bin is arranged in the detection body, a heating plate is mounted in the first liquid bin, a feeding port is mounted at the top of the detection body, and a discharge port is mounted at the bottom of the detection body. A feeding pipeline is arranged in the detection body, a ventilation pipeline is arranged at the top of the first liquid bin, a sliding groove is formed in the detection body, a filtering frame is movably installed in the sliding groove, and an exhaust pipe is arranged at the top of the detection body. Ammonia water and a phenolphthalein solution are added into the first liquid bin and the second liquid bin respectively, the controller is provided with the heating piece for constant-temperature heating, volatilized ammonia gas flows through the filtering frame through the ventilation pipeline to reach the second liquid bin, and the ammonia gas reacts with mixed phenolphthalein to change color; and the ammonia removal effect of the fabric is judged by observing the color change speed and color change degree of the phenolphthalein solution in the second liquid bin.

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 present invention aims to provide a cell inoculum and a cell transplantation substrate which can be subcultured without causing cell transformation and can effectively implant cells. An inoculum and a transplantation substrate containing a phenolphthalein derivative for facilitating implantation of cultured corneal endothelial cells or corneal endothelial replacement cells. The inoculum and the transplantation substrate can facilitate adhesion of cells during subculture and implantation of cells during transplantation.

The application relates to the technical field of processing and preparation of wood-based functional materials, and particularly discloses a wood-based friction material with a service life self-monitoring function and a preparation method thereof, which comprises the following steps: dispersing poplar powder in a co-solvent formed by mixing choline chloride and dihydroxide oxalic acid to obtain a mixed liquid, diluting and washing with water to obtain filter residue A; dispersing the filter residue A in distilled water I, adding sodium chlorite and acetic acid, stirring, and washing with water to obtain filter residue B; dispersing the filter residue B in distilled water II, adding phenolphthalein, and crushing to obtain a dispersion liquid; adding sodium chloride, solid Tris and tannic acid into the dispersion liquid, stirring, and washing with water to obtain filter residue C; dispersing the filter residue C in distilled water III, adding polyvinyl alcohol, stirring, pouring into a mold, and drying; dispersing the filter residue A in distilled water, adding sodium hydroxide and polyvinyl alcohol, stirring to obtain a mixed base liquid, continuously pouring into the mold, and drying to obtain the wood-based friction material. The friction material has the service life self-monitoring function, and the method is simple and low in cost.

The application provides a crosslinked thermal rearrangement polybenzoxazole hollow fiber gas separation membrane and a preparation method and application thereof, and belongs to the technical field of polymer membrane separation. In the synthesis of the polymer, a phenolphthalein-based diamine monomer with a lactone ring is introduced, so that the phenolphthalein-based diamine monomer is polycondensed with a dianhydride to form a polyimide, and then the polyimide is prepared into a hollow fiber membrane precursor, and then crosslinking is performed at a lower temperature, and then the temperature is further increased to prepare a thermal rearrangement hollow fiber membrane. At this time, the polymer chains are crosslinked, the flowability is hindered, the thickening degree of the skin layer is greatly reduced, and the plasticization resistance is also improved.

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 invention discloses a dosage calculation method for reducing sewage hardness through a dual-alkali method. The method comprises the specific calculation steps that 1, the total hardness and calcium hardness of sewage are measured; 2, calculating the magnesium hardness; step 3, determining phenolphthalein alkalinity and methyl orange alkalinity of the sewage; 4, calculating the concentrations of hydroxide, carbonate and bicarbonate; step 5, setting a double-alkali excess amount; step 6, calculating the dosage of NaOH; and step 7, calculating the dosage of Na2CO3. Compared with the prior art, the method has the advantages that the calculation precision is high: based on the actual ion concentration (calcium and magnesium hardness and alkalinity) of the sewage and a clear chemical reaction metering relationship, the blindness of a trial and error method is avoided, the dosage can be accurately controlled, and the risk of agent waste (cost reduction) or substandard hardness reduction (membrane scaling prevention) is reduced; the response speed is high; the operation is simple; the economical efficiency is good; the applicability is wide.

The application discloses a reaction type thermoplastic resin with a large free volume, a preparation method and a bismaleimide resin composition, and belongs to the technical field of polymer material toughening. N 2 a nucleophilic polycondensation reaction to obtain a polyaryletherketone / sulfone copolymer containing a reaction type group, wherein the bisphenol compound is selected from one or more of phenolphthalein, thymolphthalein, bisphenol fluorene and isoindolinone-based bisphenol. The application introduces a bisphenol compound with a large side group into the molecular chain of the thermoplastic resin to construct a large free volume structure, and simultaneously utilizes TGSH to provide an active propenyl group, so that the resin can participate in the curing and cross-linking reaction of bismaleimide. The bismaleimide resin composition using the resin as a toughening agent has a significantly improved toughness after curing.

The application discloses a coating and a preparation method and application thereof, and belongs to the technical field of coating materials.The coating comprises a base material, a phenolphthalein type polyether ketone and an inorganic filler.The coating has excellent high-temperature resistance, insulation, fireproof and flame-retardant properties.

The present invention provides a preparation method of a phosphorus-containing compound modified imido epoxy resin, comprising the following steps: step 1: reacting phenolphthalein and p-aminophenol to obtain an imido-containing polyphenol compound; step 2: reacting the imido-containing polyphenol compound and epichlorohydrin to obtain an imido-containing multifunctional epoxy resin; step 3: reacting the imido-containing multifunctional epoxy resin with a phosphorus-containing compound to obtain a phosphorus-containing compound modified imido epoxy resin. Imide groups and epoxy groups are gradually introduced into the phosphorus-containing compound, and the generated phosphorus-containing compound modified imido epoxy resin contains more benzene rings and imide structures, thereby improving the heat resistance of the epoxy resin. The N element in the imide group and the P element in the phosphorus-containing compound utilize the N-P synergistic effect to enhance flame retardancy while reducing phosphorus content, thereby reducing the water absorption rate of the resin.

The invention relates to the technical field of cables, and particularly discloses a surface wear-resistant cable and a preparation method thereof. The surface wear-resistant cable sequentially comprises a conductor, an insulating layer, a protective layer and a wear-resistant coating from inside to outside. Wherein the preparation raw materials of the wear-resistant coating comprise polyarylene ether nitrile ketone, a modified filler, an anti-aging agent, an antioxidant and organic silicon master batch, the modified filler is formed by compounding graphene nanosheets and silicon carbide micro powder, sulfonated polyarylene ether nitrile is formed through the joint reaction of 2, 6-difluorobenzonitrile, phenolphthalein and 2, 5-potassium dihydroxybenzenesulfonate, the composite filler is modified, and the wear-resistant coating is obtained. The surface hardness of the coating is improved, the wear resistance of the coating is enhanced, good dispersion of the nano filler in the coating is promoted, good binding force between filler particles and a matrix is ensured, and the coating forms a firm transfer film, so that the coating shows excellent wear resistance.

The invention relates to the field of pipes, and discloses a high-temperature-resistant MPP pipe and a preparation method thereof.The high-temperature-resistant MPP pipe comprises polypropylene resin, modified inorganic filler, a functional additive, ammonium polyphosphate and auxiliaries; the modified inorganic filler is prepared by grafting phenolphthalein POSS-based benzoxazine on the surface of the inorganic filler; the phenolphthalein POSS-based benzoxazine is prepared from a phenolphthalein silane coupling agent, paraformaldehyde and monoamino polyhedral oligomeric silsesquioxane through Mannich condensation reaction, wherein the phenolphthalein silane coupling agent is prepared by reacting phenolphthalein with 3-isocyanate propyl trimethoxy silane; the paraformaldehyde and the monoamino polyhedral oligomeric silsesquioxane are subjected to Mannich condensation reaction; according to the functional additive, phosphorus oxychloride is sequentially subjected to substitution with pentaerythritol phosphate and anhydrous piperazine to prepare a piperazinyl phosphorus-containing intermediate, then the piperazinyl phosphorus-containing intermediate and chloroacetyl chloride are subjected to substitution, and then the piperazinyl phosphorus-containing intermediate and dodecyl dimethyl tertiary amine continue to react to prepare the functional additive. The pipe is endowed with good mechanical property, high temperature resistance, flame retardance, water resistance and antibacterial property.

The application provides a resin composition, a prepreg, a laminated board and a preparation method thereof. The resin composition comprises the following components in parts by mass: 40-100 parts of phthalonitrile-terminated polyphenyl ether, 10-40 parts of phenolphthalein-based polyaryletheramine and 10-60 parts of inorganic filler; the structure of the phthalonitrile-terminated polyphenyl ether is shown in formula (I), and the structure of the phenolphthalein-based polyaryletheramine is shown in formula (II); wherein a, m and n are all positive integers, and Y is C1-C3 alkylene or a single bond. The laminated board prepared from the resin composition has high peeling strength, high decomposition temperature, high elastic modulus, good flame retardation, low dielectric coefficient, low water absorption and other excellent comprehensive properties.

The invention discloses a phenolphthalein polyaryletherketone nano composite material and a preparation method thereof, the composite material comprises the following components by mass: 50-70 wt% of a phenolphthalein polyaryletherketone (PEK-C) matrix, 10-30 wt% of a nano filler, 5-15 wt% of a flexibilizer, 1-5 wt% of an antioxidant, and 1-3 wt% of a processing aid, wherein all the components are physically mixed to form a uniformly dispersed integral structure, and the preparation method comprises the following steps: S1, pre-mixing the phenolphthalein polyaryletherketone matrix and the nano filler in a high-speed mixer; s2, adding the premixed materials into a double-screw extruder, and carrying out melt blending; s3, adding a toughening agent, an antioxidant and a processing aid in the extrusion process, and continuously mixing; and S4, cooling and pelletizing the extruded material to obtain the nano composite material particles. The invention belongs to the field of high polymer materials, and particularly relates to a phenolphthalein polyaryletherketone nanocomposite and a preparation method thereof.

The application discloses a preparation method and application of a phenolphthalein intercalated ammonium vanadate material. The phenolphthalein intercalated ammonium vanadate material is synthesized by a one-step solvothermal method, ammonium metavanadate is used as a vanadium source, a mixed solution of ethylene glycol and water is used as a reaction medium, and oxalic acid is used as a reducing agent, so that the phenolphthalein intercalated ammonium vanadate material is obtained under a solvothermal condition. The phenolphthalein molecules between layers of the material play a role of a support, and the hydrophobic phenolphthalein molecules can reduce direct contact between the material and water molecules, inhibit structural collapse and dissolution of the material in a cycle process and the like, and the material is applied to a water-based zinc ion battery as a positive electrode material, so that more excellent electrochemical performance and cycle stability are obtained.

The invention relates to the technical field of concrete detection, and discloses a concrete carbonization tester which comprises a tester body and a cover plate located at the rear end of the tester body, a nozzle is installed at the upper end of one side of the tester body, and a camera, a light supplementing lamp and a distance measuring probe are installed on the side, away from the nozzle, of the upper end of the tester body. A solvent in the solvent conveying mechanism and a solute in the solute conveying mechanism are mixed in the mixed liquid spraying mechanism to form a detection solution; spraying a phenolphthalein solution into the hole from the nozzle; the color of the carbonized part and the uncarbonized part is changed; the distance between the color-changing junction and the surface of the concrete is detected through the distance measuring probe, so that the specific carbonization depth can be measured; when the distance measuring probe measures the distance, the camera can shoot an image in the hole, and the image is displayed on the display screen, so that a color-changing junction can be accurately positioned; the tester can realize automatic batching and automatic detection.

The invention discloses a water conservancy gate detection device, which comprises an outer frame, and further comprises an execution device comprising a drilling assembly and a sealing disc; the liquid guide cylinder is fixedly connected to the inner wall of the sealing disc and is used for filling a phenolphthalein solution; the carbonization depth measuring scale is mounted at one end, positioned on the wall body to be measured, of the sealing disc and is used for measuring the carbonization depth of the drilled wall body; the driving motor is mounted at one end, opposite to the sealing disc, of the outer frame and is used for driving the drilling assembly, the liquid guide cylinder and the carbonization depth measuring scale to perform position switching; and a negative pressure adsorption device. The negative pressure adsorption device and the execution device are arranged, the whole process functions of punching, color development and measurement are integrated, a drilling assembly is arranged in the execution device, a measurement hole site meeting the requirement can be punched in a to-be-measured wall surface, a special phenolphthalein solution can be sprayed out of the hole site through a liquid guide cylinder, the hole site after color development can be detected through a carbonization depth measuring ruler, and the measurement accuracy is improved. Divers do not need to frequently replace tools.

The application discloses a method for detecting the acidity of a circulating solution of electro-deposited cobalt, which comprises the following steps: removing oxidizing substances in the circulating solution of electro-deposited cobalt by potassium iodide in an acidic medium; reacting the potassium iodide with potassium iodate and acid to generate iodine molecules; titrating with a sodium thiosulfate standard solution until the solution changes from blue or blue-black to the original color of the solution, which is the end point; and calculating the acidity content according to the mass balance. The method can effectively remove the oxidizing substances in the solution to be measured, avoid the interference with the determination of the acidity content, and make the detection result more accurate. The sodium thiosulfate is innovatively applied to the detection of the acidity of the circulating solution of electro-deposited cobalt, and the sodium thiosulfate titration is used to replace the commonly used sodium hydroxide titration method, so that the interference of the original color of the light red solution with the color judgment of the end point of the sodium hydroxide (phenolphthalein as an indicator) is avoided.

The invention discloses a method for measuring the total concentration and free concentration of citric acid in a chemical cleaning process, which comprises the following steps: firstly, sequentially filtering and diluting a pickling solution to be measured, then enabling the diluted pickling solution to flow through a hydrogen type cation exchange resin column, and collecting an outflowing exchange solution; then titrating the collected exchange liquid by adopting phenolphthalein as an indicator and a NaOH solution as a titrant to obtain the total concentration of citric acid; and finally, obtaining the concentration of free citric acid according to the total concentration of citric acid and the total iron ion concentration. According to the method, the total concentration and free concentration of citric acid in the complex chemical cleaning solution are rapidly and accurately measured through selective exchange of the resin column and step-by-step titration analysis. The method shows high precision, high efficiency and strong anti-interference performance in industrial field verification, and a reliable technical scheme is provided for industrial scenes such as power station boiler chemical cleaning.

The invention relates to a device and method for measuring the alkalinity of a water sample based on an ORP electrode. The device comprises a controller, a measuring component and a sample adding component. The measuring component comprises a water sample container and an ORP electrode. The water sample container is used to place a water sample to be measured. The ORP electrode is electrically connected to the controller and is arranged in the water sample container. The sample adding component comprises a metering pump. The metering pump is connected to a standard hydrochloric acid solution container and the water sample container through a pipeline and is electrically connected to the controller. By adopting the ORP electrode, a change in the ORP redox potential is utilized during the titration process to identify the endpoint of the titration, replacing manual judgment of the color change endpoint in the titration. The device has good measurement accuracy and consistency, and can accurately measure the phenolphthalein alkalinity and total alkalinity in water quality. Compared with the limitation that an optical titration method is only applicable to colorless and low-turbidity water samples, the ORP electrode can measure not only colorless and low-turbidity water samples, but also colored water samples and water samples with a certain turbidity. It has a wide range of applications and can realize online and real-time measurement.

The invention relates to the technical field of lithium ion battery positive electrode material detection, in particular to a method for measuring the content of soluble lithium in a lithium manganate finished product, which comprises the following steps of: taking 5g of lithium manganate finished product sample, putting into a 250mL beaker, adding 50mL of purified water and a magnetic stirrer, covering, stirring for 20 minutes at the rotating speed of 550r / min, standing for 2 minutes, and filtering supernate by two layers of filter paper; transferring 10 mL of filtrate to a 250 mL conical flask, adding 40 mL of purified water, firstly adding 2 drops of phenolphthalein, titrating with 0.0104 mol / L hydrochloric acid until the solution is colorless (denoted as v1), then adding 3 drops of methyl red, continuously titrating until the solution is orange, boiling for 1 min, cooling, titrating until the solution is wine red (denoted as v2), and calculating according to the formula that the content of lithium carbonate is equal to (v2-v1) * 0.0104 * 73.886 / m; the method for determining the content of soluble lithium in the lithium manganate finished product is simple and accurate to operate, rapid and efficient, can optimize the process, saves time and labor, can determine the quality of soluble lithium so as to judge the performance of a material body in advance, and ensures the production of high-quality lithium manganate.