8 results about "Back titration" patented technology

The invention relates to the technical field of zinc hydrometallurgy, and discloses an analysis method for measuring high cobalt content by an EDTA complexing back titration method, which is based on the following steps: oxidizing Co < 2 + > into Co < 3 + > by using potassium nitrite in an acetic acid medium to form cobalt potassium nitrite precipitate so as to realize separation of cobalt and interfering ions, dissolving the precipitate, complexing with excessive EDTA, and performing back titration by using a zinc standard solution. Xylenol orange is used as an indicator, and determination is completed at room temperature in a hexamethylenetetramine buffer system with the pH value being approximately equal to 5.8. Coexisting ion interference is effectively eliminated through tartaric acid, sodium fluoride, thiourea and other masking agents, the method has the advantages of being easy and convenient to operate, sensitive in end point, high in accuracy and low in cost, and the requirement for conventional analysis of high-cobalt materials can be met.

The invention discloses a soil organic carbon mineralization rate determination method, and relates to the technical field of soil carbon circulation and greenhouse gas monitoring. The method comprises the following steps: carrying out hydrochloric acid back titration on an absorption liquid by adopting an automatic potentiometric titration method, converting to obtain the mass of a carbon element contained in carbon dioxide, calculating the mineralization rate by combining the dry soil weight and the culture interval, and finally subtracting an inactivation control value to obtain the organic carbon mineralization rate driven by pure microorganisms. A thin-wall stainless steel undisturbed soil drill matched with the inner diameter of a culture bottle is used for collecting soil columns in a layered manner, PVC liner tube sealing and constant-temperature transportation are matched, and a cold chamber for simulating the in-situ temperature is combined, so that the in-situ structure and the microbial habitat of the loose high-water-content peat soil are reserved to the maximum extent, and damage of traditional pretreatment to soil pores and microbial communities is avoided.

The invention discloses a method for determining the content of phenol in an iron-dextran injection / solution through combination of iron-sodium dihydrogen phosphate precipitation impurity removal and back titration, and relates to the field of analytical chemistry. According to the method, pretreatment is realized through precipitation reaction of iron and sodium dihydrogen phosphate, and interference of iron ions in iron dextran on detection is eliminated. Phenol and bromine are subjected to a bromo-phenol reaction through a potassium bromate-potassium bromide system, excessive bromine and potassium iodide are subjected to a reaction to generate iodine, a sodium thiosulfate titration solution is used for titration by means of an iodometric method, and the content of phenol is calculated. The method does not need a precise instrument, is simple and convenient to operate, can simply, quickly and accurately measure the phenol content in the iron-dextran injection / solution, effectively solves the problem of the existing detection technology in the detection of the sample, fills the technical gap in the detection of the phenol content of the iron-dextran preparation in China, and has a good application prospect. And a brand new solution is provided for veterinary drug production quality control and related detection work.

This invention provides an automated potentiometric titration method for determining the platinum content in platinum jewelry, belonging to the field of precious metal analysis and detection technology. The method mainly includes: dissolving the platinum jewelry sample in aqua regia and using a separating reagent to precipitate and separate interfering precious metals such as palladium, gold, and silver. Subsequently, the sample is passed through a strongly basic anion exchange resin column, where platinum is selectively adsorbed as chloroplatinate complex anions to obtain a purified platinum solution. The platinum content is calculated using a back titration method. This method integrates interfering element separation, ion exchange purification, back titration, and automated potentiometric detection technologies, and optimizes the electrode system. This method has the advantages of high accuracy, good precision, strong anti-interference ability, and relatively simple and reliable operation, and is suitable for the accurate determination of platinum content in platinum jewelry and platinum alloys of various purities such as Pt900, Pt950, and Pt990.

This invention relates to a method for producing and purifying MMAE. By employing a purification method using back titration crystallization of toluene and n-heptane instead of the column chromatography purification procedure used in conventional techniques, production efficiency is significantly improved and solvent usage is effectively reduced. Furthermore, the MMAE produced by this production and purification method has high yield and purity, effectively reducing production costs, and the method is stable, making it suitable for scale-up production.

This invention relates to a method for determining monomer content in cement systems based on bromoaddition back titration and its application. Specifically, it provides the application of bromoaddition back titration in establishing monomer polymerization kinetics in cement-based material systems modified by in-situ polymerization. Addressing the technical challenge of synergistically controlling polymerization and cement hydration in the preparation of organic-inorganic interpenetrating network (IPN) cementitious materials, this invention proposes a dynamic monitoring scheme based on an improved bromoaddition back titration method. This scheme aims to solve the problem of existing detection methods failing in highly alkaline, multiphase, and temperature-changing environments of cement pastes—traditional methods such as spectroscopy, chromatography, and rheology are difficult to accurately identify polymerization behavior in such systems. By cleverly applying bromoaddition back titration to determine monomer concentration, monomer conversion rate, and polymerization rate in cement-based material systems, and considering various influencing factors, it can be used to establish monomer polymerization kinetics.

The invention provides a method for detecting the content of basic ions in drilling chemicals, which adopts a two-step titration mode, strong acid is titrated until CO2 is discharged from a medium-strong acid environment, strong alkali is dripped back to the pH value of an original to-be-detected solution, the interference of amine, organic acid radicals, borate radicals, silicate radicals and other ions in the drilling chemicals can be removed, and the content of the basic ions in the drilling chemicals can be determined by substituting the amount of the consumed strong alkali into a correction formula according to the amount of the consumed strong alkali. And accurate unit contents of hydroxyl, carbonate and bicarbonate can be obtained. The method is mainly suitable for detecting or measuring the content of basic ions such as hydroxyl, carbonate and bicarbonate in the drilling fluid or the drilling fluid treating agent, interference of other groups or ions in the national standard can be avoided, and carbonate and bicarbonate are converted into carbon dioxide and discharged on the basis of strong acid titration; strong base back dropping is used, the content of interference groups or ions such as amine, organic acid radicals, borate radicals and silicate radicals is measured, the content of hydroxyl ions, carbonate ions and bicarbonate ions is corrected, and the measuring accuracy is high.

The invention provides a method for titration determination of platinum content in platinum jewelry by an automatic potentiometric method, and relates to the technical field of precious metal analysis and detection. The method mainly comprises the following steps: dissolving a platinum jewelry sample with aqua regia, and precipitating and separating precious metal interference elements such as palladium, gold and silver by using a separation reagent. And enabling the platinum to pass through a strongly basic anion exchange resin column, so that the platinum is selectively adsorbed in the form of chloroplatinic acid radical complex anions, and obtaining a purified platinum solution. And calculating the content of platinum by adopting a back titration method. The method integrates interference element separation, ion exchange purification, back titration and automatic potential detection technologies, optimizes an electrode system, has the advantages of high accuracy, good precision, strong anti-interference capability and relatively simple and reliable operation, and is suitable for accurate determination of the platinum content in platinum jewelry and platinum alloy with various purities such as Pt900, Pt950, Pt990 and the like.