53 results about "Molar mass" patented technology

A composition comprising an aqueous suspension comprising a small molecule therapeutic agent and an organic acid is described. The small molecule therapeutic agent is a base and has a water solubility at room temperature of less than about 1.0 g / L. The organic acid has a water solubility at room temperature of between 0.1 and 10, has a molar mass of less than 500 grams per mole, and / or maintains a pH of the suspension in its environment of use of between 3.0-6.5. The organic acid enhances the solubility of the small molecule therapeutic agent and when present in stoichiometric excess, the organic acid drives release of the small molecule therapeutic agent into a buffered environment of use for prolonged periods of, for example, six months to one year. Devices comprising the compositions and methods of treatment are also described.

The CVD reactor (1) according to the invention has a process chamber (2) having a process chamber height (H1, H2, H3, H4) that varies stepwise in flow direction (S). The position of the steps or inert gas flows (Q1, Q2, Q3) which are fed into the process chamber (2) at different positions (d1, d2, d3) and the molar mass of which is greater than 20 g / mol leads to a reduction of inhomogeneities in a layer that are otherwise observed at the edge of a substrate.

The invention relates to a method for pulling a single crystal from a melt consisting of silicon and a dopant according to the Czochralski method, comprising the following steps in a given sequence: a) performing a time-dependent computer simulation of a predetermined crystal pulling process having a predetermined dopant concentration (C) in the melt, with the aim of obtaining a temperature gradient and a dopant gradient for each time increment t, wherein the two gradients are determined at the interface between the crystal and the melt in the normal direction of the melt interface, b) determining a maximum dopant concentration (Cmax) in the melt, and c) pulling up a single crystal having a dopant concentration less than the determined maximum dopant concentration (Cmax), characterized in that a parameter (CS) is calculated for each time increment t, which is determined by formula, wherein the parameter fCS is determined from the product of the average concentration (C) of the dopant in the melt, the density of the silicon melt, the Avgamde constant, the molar mass of the silicon and the slope of the liquidus, and then generating an average value of the values obtained for the parameter (CS) wherein only those values having the (CS) value less than zero are included, and determining the maximum dopant concentration (Cmax) by adapting the above defined dopant concentration (C) until the magnitude equals zero.

The invention relates to a two-component thermally conductive composition comprising: a composition (A) comprising: a silylated polymer, and a rheology agent (r1) selected from amide waxes and / or a rheology agent (r2) comprising: from 1% to 40% by weight of a bis-urea (a) obtained by reacting a primary aliphatic amine with a diisocyanate of molar mass less than 500 g / mol, relative to the total weight of the rheology agent (r2), and from 60% to 99% by weight of a specific plasticizer (b), relative to the total weight of the rheology agent (r2), said rheology agent (r2) being in the form of a suspension of solid particles of the bis-urea (a) in a continuous phase of plasticizer (b), and a composition (B) comprising: at least 1% by weight of a filler (C) relative to the total weight of the composition (B), the filler (C) contributing at least 0.0025% by weight of moisture relative to the total weight of the composition (B),Composition (A) and / or composition (B) further comprising at least one thermally conductive filler. The invention also relates to the use of a filler (C) having a specific moisture content for crosslinking, without the addition of free water, a two-component composition, the two-component composition comprising a composition (A) comprising a silylated polymer, and a composition (B) comprising said filler (C). Figure for the abstract: none.

The invention relates mainly to a polymer composition comprising: (a) 55% to 99%, preferably 60% to 95%, advantageously 65% to 90%, and in particular 70% to 85% by weight of polyether block amide (PEBA) having a ratio of the number-average molar mass of the polyamide blocks to that of the polyether blocks of 1.0 or less; (b) 1% to 45% by weight of a modifier selected from among: i. a thermoplastic elastomer in the form of a block copolymer with a ratio D of the number-average molar mass of the rigid blocks to that of the soft blocks of less than 0.8; ii. a crude or crosslinked rubber; and iii. combinations thereof; (c) 0% to 5% by weight of additives; and (d) 0% to 5% by weight of fillers, the sum of the percentages of components (a) to (d) adding up to 100%, and wherein the composition comprises less than 4% by weight of carbon black.

The invention relates to the technical field of environment detection, in particular to a method for determining the molar mass of fulvic acid in a lake water body based on a three-dimensional fluorescence spectrum. The method comprises the following steps: (a) extracting and purifying fulvic acid in lake water; (b) preparing a tested solution of fulvic acid in the lake water body; (c) selecting a fluorescence peak position of a titration experiment; (d) fluorescence quenching titration of fulvic acid; and (e) calculating the molar mass of fulvic acid. According to the method, only conventional laboratory equipment is used, and the requirement for the skill of an experiment operator is not high. Model compounds such as tyrosine and fulvic acid standard samples are used for verification, and the accuracy and reliability of the method are proved.

The present invention relates to a two-component thermally conductive composition comprising:-a composition (A) comprising 0 a silane-based polymer, and-a composition (B) comprising 0 at least 1% by weight of a filler (C), relative to the total weight of composition (B), said filler (C) providing at least 0.0025% by weight of moisture, relative to the total weight of composition (B), composition (A) and / or composition (B) further comprises at least one thermally conductive filler, and composition (A) and / or composition (B) further comprises: 0 of a rheological agent (r1) selected from amide waxes and / or 0 of a rheological agent (r2) comprising: from 1% to 40% by weight of a diurea (a) relative to the total weight of the rheological agent (r2), the invention relates to a composition comprising a rheological agent (r2) in the form of a diurea (a) obtained by the reaction of an aliphatic primary amine with a diisocyanate having a molar mass of less than 500 g / mol, and from 60% to 99% by weight of a specific plasticizer (b), relative to the total weight of the rheological agent (r2), in the form of a suspension of solid particles of the diurea (a) in the continuous phase of the plasticizer (b). The invention also relates to the use of a filler (C) having a specific moisture content for the cross-linking of a two-component composition comprising a composition (A) comprising a silane-based polymer and a composition (B) comprising the filler (C), without the addition of free water.

The invention relates to a composition which can be fixed by actinic radiation and cured by heat, the composition comprising: (A) an at least bifunctional, passivated, and solid isocyanate; (B) an isocyanate-reactive component which comprises at least one liquid hybrid compound (B1) which, in addition to at least one isocyanate-reactive group, contains at least one radically curable group, the hybrid compound (B1) having a molar mass of at least 400 g / mol; and (C) an initiator system for radical polymerisation, which comprises a first initiator (C1) and a second initiator (C2), the first initiator (C1) being a radical photoinitiator and the second initiator (C2) being a radical initiator for heat curing. The invention also relates to a method for bonding, casting and / or coating substrates, and to a use of a curable composition.

The invention discloses an improved method suitable for a'volatile substance molar mass determination 'experiment in a physical and chemical experiment established in a higher school. Comprising the following steps: S1, firstly, lapping a device, and replacing an original Meijoa method steam density measuring device with an improved two-mouth round-bottom flask and a soap film flowmeter; s2, replacing an original three-way piston with a T-shaped pipe; and S3, replacing glass bubbles with a medical injector sample injection mode. Experiment results show that the improved experiment is simple in operation and obvious in phenomenon, experiment cost and uncertainty are reduced, and the method is more suitable for grouping experiments of students.

In order to improve process control in a reaction chamber (14), for example a bioreactor, in particular in cell culture or fermentation, the invention provides a measuring method for measuring the concentration (cz) of a gas component (Z) to be measured of a gas mixture (12b) of known composition in a liquid solution in a reaction chamber (for example a bioreactor) (14), having the following steps: a) providing a measuring chamber (16), the measuring chamber (16) is separated from the interior of the reaction chamber (14) through a breathable isolating membrane (18); b) measuring the gas density (rho), the gas pressure (p) and the temperature (T) within the measurement chamber (16); and c) determining the concentration (cz) of the gas component (Z) to be measured from the values measured in step b) and from the molar masses of the gas components (X, Y, Z) of the gas mixture.

Use, in an application for grinding, dispersion in a wet medium or surface treatment, of a powder of sintered beads, said powder having: - a chemical composition such that, as percentages by mass based on the mass of the bead powder: - (77 - C4)% ≤ W + Mo ≤ (97.5 - C3)%, with Mo ≤ 10%; - C1% ≤ C ≤ C2%; - 2.5% < additive ≤ 20.0%, the additive denoting Ti + Ta + Nb + V + Zr + Hf; - elements other than W, Mo, C, Ti, Ta, Nb, V, Zr, Hf, or "other elements": ≤ 3%; with: - C1 = 100*(C3 / C5), - C2 = 100*(C4 / C6), - C3 = k*C7, with k selected from 0.5, 0.6, 0.7, 0.8 and 0.9, - C4 = k'*C7, with k' selected from 1.2 and 1.1, - C5 = [m(W) + m(Mo) + m(Ti) + m(Ta) + m(Nb) + m(V) + m(Zr) + m(Hf) + C3], - C6 = [m(W) + m(Mo) + m(Ti) + m(Ta) + m(Nb) + m(V) + m(Zr) + m(Hf) + C4], - C7 = M(C)*[(m(W) / M(W)) + (m(Mo) / M(Mo)) + (m(Ti) / M(Ti)) + (m(Ta) / M(Ta)) + (m(Nb) / M(Nb)) + (m(V) / M(V)) + (m(Zr) / M(Zr)) + (m(Hf) / M(Hf))], m(W), m(Mo), m(Ti), m(Ta), m(Nb), m(V), m(Zr) and m(Hf) being the mass, in grams, of the elements W, Mo, Ti, Ta, Nb, V, Zr and Hf, respectively, and M(W), M(Mo), M(Ti), M(Ta), M(Nb), M(V), M(Zr), M(Hf) and M(C) being the molar mass, in g / mol, of the elements W, Mo, Ti, Ta, Nb, V, Zr, Hf and C, respectively; - a crystallographic composition such that more than 60% of the crystalline phases present in said bead powder are in the form of metal carbide(s), as percentage by mass based on the mass of the crystalline phases, said crystalline phases including at least one carbide of at least one element from among Ti, Ta, Nb, V, Zr and Hf.

The invention relates to a method for producing linear organopolysiloxanes OL by polymerization of organopolysiloxanes O (cyclic and / or linear) using a catalytic system AI. More specifically, the method of the present invention makes it possible to obtain a controlled molar mass linear organopolysiloxane OL with a very low residual ratio of cyclic organopolysiloxane. The present application also relates to linear organopolysiloxanes (OL) obtained according to various embodiments of the above process of the present invention.

The present invention relates to a rubber composition based on at least one elastomer matrix, a reinforcing filler, a vulcanization system and a plasticizing system comprising at least one estolide having a weight-average molar mass (Mw) of less than 5000 g / mol as biobased plasticizer.

The present invention is directed to a radical-curable coating composition comprising(A) One or more oligomers selected from the group consisting of urethane (meth)acrylates, (meth)acrylated epoxidized triglycerides and any mixture thereof, wherein said oligomers have a molar mass equal to or higher than 800 g / mol and lower than 4500 g / mol,(B) One or more methacrylate reactive diluents having a molar mass lower than 800 g / mol, wherein said methacrylate reactive diluents have an average methacrylate functionality higher than 2,(C) One or more acrylate reactive diluents having a molar mass lower than 800 g / mol, wherein said acrylate reactive diluents have an average acrylate functionality higher than 2,(D) One or more photo-initiators, and(E) One or more thermal initiators,wherein the acrylate functionalities of the acrylate reactive diluents (C) and the methacrylate functionalities of the methacrylate reactive diluents (B) are present in a molar ratio of the acrylate functionalities to the methacrylate functionalities of at least 0.2,wherein the amount of oligomers (A) is higher than 20 wt. % and lower than 90 wt. % and the amount of reactive diluents (B) and (C) is higher than 10 wt. % and lower than 80 wt. %, based on the total amount of (A), (B) and (C), andwherein the total amount of (A), (B) and (C) is at least 25 wt. % of the radical-curable coating composition.

The invention relates to a lubricating composition comprising water and: - from 0.05 to 40% by weight of at least two polyalkylene glycols, PAG1 and PAG2, the ratio between the molar mass of PAG1 and the molar mass of PAG2 being strictly less than 1; - from 0.001 to 30% by weight of at least one cellulosic compound, relative to the total weight of the lubricating composition. The present invention also relates to the use of the lubricating composition according to the invention for metalworking.

There is a need for a novel heat-melt curable organopolysiloxane composition, etc. This invention provides a heat-melt curable organopolysiloxane composition comprising: (A) a chain-like organopolysiloxane having two or more alkenyl groups within its molecule; (B) an organopolysiloxane component selected from two or more components (B1) to (B3) that do not contain aliphatic unsaturated bonds: (B1) an organopolysiloxane resin containing R... 1 3SiO 1 / 2 (where R) 1 The siloxane unit (M unit) representing a monovalent organic group independently, and the siloxane unit (M unit) represented by SiO2. 4 / 2 The following are defined as follows: (A) a siloxane unit (Q unit), and the molar mass ratio of M unit to Q unit is in the range of 0.50 to 2.00; (B2) a linear or branched diorganopolysiloxane; and (B3) an organopolysiloxane resin, wherein the organopolysiloxane resin is formed by chemically linking components (B1) and (B2); (C) a monofunctional or polyfunctional vinyl monomer; and (D) a free radical polymerization initiator, wherein the ratio (R / P ratio) of the total mass R of component (B1) and component (B1) constituting component (B3) to the total mass P of component (A), component (B2) and component (B2) constituting component (B3) exceeds 1.80.

A process for producing a first intermediate product comprising the steps of: a. Providing a feedstock comprising a first polyester; b. Contacting the first polyester with a further amount of a first organic compound in a volume segment V2, where i. At least one impurity is present in the volume segment V2, and ii. The volume segment V2 has a first region and a further region; c. Contacting the first polyester with a further organic compound, preferably in volume segment V3, to obtain a further initial mixture; d. Reducing the weight average molar mass of the first polyester, preferably in the volume segment V3, to obtain a first intermediate mixture comprising i. The first intermediate product, ii. A further organic compound; wherein the relative ratio of the number of particles per unit area of at least one impurity in the first region to the number of particles per unit area of at least one impurity in the other region is equal to or greater than 10, more preferably equal to or greater than 15, even more preferably equal to or greater than 20, further preferably equal to or greater than 25, even further preferably equal to or greater than 30.

The application discloses a kind of based on electronic density and distribution uniformity Fractal dimension calculation method and general detection device, belong to material microstructure characterization technical field.The method determines material chemical formula unit total price electron number, theoretical dense density and molar mass, detects actual density and calculates porosity;Collect surface topography gray data, calculate electronic distribution uniformity by normalized variance;Total price electron number density is calculated, combined with fitting proportion coefficient, and the fractal dimension is obtained by general formula.The detection device uses modular architecture, including basic parameter input, density detection, uniformity acquisition, main control calculation and result output module, each module can be independently replaced, and the main control module is built-in core algorithm.The application does not need large microscopes, realizes fast, low-cost detection, adapts to various solid materials, wide protection range, easy industrialization, solves the problems of high cost, complicated process, poor universality and easy to avoid in prior art.

The stoichiometric formula of the high-entropy perovskite oxide doped ceramic is (1-x) Ca0. 5Sr0. 5TiO3-xNBBSC, and x is more than or equal to 0.05 and less than or equal to 0.2. The preparation method comprises the following steps: step 1, weighing and mixing original powder according to the molar mass percent of the chemical formula of Ca0. 5Sr0. 5TiO3 and NBBSC to form mixed powder A and mixed powder B; 2, the mixed powder A and the mixed powder B are subjected to ball milling, drying and presintering respectively, and Ca0. 5Sr0. 5TiO3 powder and NBBSC powder are obtained respectively; step 3, the Ca0. 5Sr0. 5TiO3 powder and the NBBSC powder are weighed according to the molar mass percentage of the chemical formula of (1-x) Ca0. 5Sr0. 5TiO3-xNBBSC, mixing, ball milling, drying and sieving are performed, and mixed powder C is obtained; and step 4, pressing the mixed powder C into a green body, and sintering the green body to obtain the (1-x) Ca0. 5Sr0. 5TiO3-xNBBSC ceramic. A high-entropy perovskite oxide NBBSC is introduced into a linear dielectric Ca0. 5Sr0. 5TiO3 matrix, and the NBBSC enters crystal lattices of Ca0. 5Sr0. 5TiO3 in a solid solution form to form a single solid solution, so that the dielectric property of the ceramic is modified and improved, the breakdown field strength of the ceramic is remarkably improved, and the ceramic obtains high energy storage density and high energy storage efficiency.

The present invention relates to a method for producing linear organopolysiloxane OL from organopolysiloxane O (cyclic and / or linear) by polymerization reaction using a catalytic system AI. More precisely, the method of the present invention makes it possible to obtain linear organopolysiloxane OL having a controlled molar mass with a very low residual cyclic organopolysiloxane. This application also relates to linear organopolysiloxane OL obtained according to various embodiments of the method of the present invention described above.

Use, in a grinding, wet dispersion or surface treatment application, of a sintered bead powder, said powder having: - a chemical composition such that, in mass percentages on the basis of the mass of the bead powder: - (77 - C4)% ≤ W + Mo ≤ (97.5 - C3)%, with Mo ≤ 10%; - C1% ≤ C ≤ C2%; - 2.5% < additive ≤ 20.0%, the additive denoting Ti + Ta + Nb + V + Zr + Hf; - elements other than W, Mo, C, Ti, Ta, Nb, V, Zr, Hf, or "other elements": ≤ 3%;with : - C1 = 100*(C3 / C5), - C2 = 100*(C4 / C6), - C3 = 0,5*C7, - C4 = 1,2*C7, - C5 = [m(W) + m(Mo) + m(Ti) + m(Ta)( Z(f) + C5) + m - C6 = [m(W) + m(Mo) + m(Ti) + m(Ta) + m(Nb) + m(V) + m(Zr) + m(Hf) + C4], - C7 = M(C)*[(m(W) / M(W)) + (m(Mo) / M(Mo)) + (m(Ta)) + (m(Ti)) + (m(Ti) / M(Nb)) + (m(V) / M(V)) + (m(Zr) / M(Zr)) + (m(Hf) / M(Hf))], m(W), m(Mo), m(Ti), m(Ta), m(Nb), m(V), m(Zr) and m(Hf) being the mass of Mo, V, Ta in grams W, des Hf, respectively, andM(W), M(Mo), M(Ti), M(Ta), M(Nb), M(V), M(Zr), M(Hf) and M(C) being the molar mass, in g / mol, of elements W, Mo, Ti, Ta, Nb, V, Zr, Hf and C, respectively;- a crystallographic composition such that more than 60% of the crystallized phases present in said bead powder are in the form of metallic carbide(s), as a percentage by mass based on the mass of the crystallized phases, said crystallized phases including at least one carbide of at least one element among Ti, Ta, Nb, V, Zr and Hf. No abbreviated figure.

Method for degrading a vinyl polymer A method for degrading a vinyl polymer having an initial molar mass in order to form at least one degradation product having a final molar mass lower than the initial molar mass comprises a) providing a water-based emulsion of the vinyl polymer; b) mixing the water-based emulsion with at least one enzyme-mediator system to obtain a reaction mixture, said at least one enzyme-mediator system comprising at least one multi-copper oxidase chosen among a laccase, a laccase-ferroxidase, a laccase-like multi-copper oxidase or a mixture thereof, and at least one respective mediator, said at least one multi-copper oxidase and said at least one respective mediator being mixed sequentially with the water-based emulsion or provided as a pre-mix preserved under anaerobic conditions, until being mixed with the water-based emulsion; c) stirring the reaction mixture under an atmosphere comprising dioxygen; and d) recovering the at least one degradation product of the vinyl polymer.

A process for producing a first intermediate product comprising the steps of: a. Providing a feedstock comprising a first polyester; b. Contacting the first polyester with a further organic compound, preferably in volume segment V3, to obtain a further initial mixture; c. Reducing the weight average molar mass of the first polyester, preferably in the volume segment V3, to obtain a first intermediate mixture comprising: i. The first intermediate product, ii. Another organic compound; d. Adding a first particulate material to the first intermediate mixture, preferably in a volume segment V4; e. Precoating the filter device with a first particulate material; f. Removing at least one impurity from the first intermediate mixture at least partially using a filtering device; wherein the first particulate material has a median pore size in the range of 5.0 [mu] m to 20.0 [mu] m, preferably in the range of 10.0 [mu] m to 20.0 [mu] m, and further preferably in the range of 15.0 [mu] m to 18.0 [mu] m.

The invention relates to a process for preparing linear organopolysiloxanes (OL) by polymerization reaction from organopolysiloxanes (O) (cyclic and / or linear), using an AI catalytic system. More specifically, the process of the present invention makes it possible to obtain linear organopolysiloxanes (OL) of controlled molar mass with a very low residual level of cyclic organopolysiloxanes. This application also relates to the linear organopolysiloxane (OL) obtained according to the various embodiments of the process of the present invention described above.

The invention relates to a vulcanizable rubber compound comprising a) a diene rubber, b) silica, c) a specific polyetheramine in a combined part by weight in the range of 0.1 to 10 phr, and d) one or more liquid polybutadienes having a number average molar mass Mn, measured by GPC, in the range of 500 to 20,000 g / mol.

The invention relates to a composition which can be fixed by actinic radiation and cured by heat, the composition comprising: (A) an at least bifunctional, passivated, and solid isocyanate; (B) an isocyanate-reactive component which comprises at least one liquid hybrid compound (B1) which, in addition to at least one isocyanate-reactive group, contains at least one radically curable group, the hybrid compound (B1) having a molar mass of at least 400 g / mol; and (C) an initiator system for radical polymerisation, which comprises a first initiator (C1) and a second initiator (C2), the first initiator (C1) being a radical photoinitiator and the second initiator (C2) being a radical initiator for heat curing. The invention also relates to a method for bonding, casting and / or coating substrates, and to a use of a curable composition.

The invention relates to a substrate comprising a surface of which at least one part is covered with an epilame agent, characterized in that said epilame agent comprises at least one compound in the form of a polymer soluble in a non-halogenated organic solvent and comprising units N, where N is formula (N), where R2, which may be identical or different, is H, a C1-C10 alkyl group, a C2-C10 alkenyl group; X, which may be identical or different, is a spacer arm; and L, which may be identical or different, is a group according to formula (I), where R6, R7 and R8, which may be identical or different, are H; a C1-C10 alkyl group; a C2-C10 alkenyl group; -(CH2)dOC(O)C(R9)=CH2, or a group according to formula (II), wherein at least one of R6, R7 and R8 is according to formula (II), where R9, which may be identical or different, is H, a C1-C10 alkyl group, a C2-C10 alkenyl group, d is selected from between 1 and 20, R10 and R11, which may be identical or different, are H, a C1-C10 alkyl group, a C2-C10 alkenyl group; R12, which may be identical or different, is H, a C1- C10 alkyl group, a C2-C10 alkenyl group, -(CH2)δO(CH2)εCH3, or (CH2)ψOC(O)C(R13)=CH2, where R13, which may be identical or different, is H, a C1-C10 alkyl group, a C2-C10 alkenyl group, δ is selected from between 1 and 20, ε is selected from between 0 and 20, ψ is selected from between 1 and 20; and y is at least 1 and is selected such that the molar mass of the L group is between 200 g / mol and 30,000 g / mol. The invention also relates to a method for coating such a substrate with epilame, and to a timepiece or piece of jewellery comprising a component that includes such a substrate.

A method for the crystal pulling of a monocrystalline crystal from a melt composed of silicon and a dopant according to Czochralski, comprising the following steps in the sequence given: a) performing a time-dependent computer simulation of a predefined crystal-pulling process with a predefined dopant concentration (C) in the melt, with the aim of obtaining a temperature gradient (ꝺc / ꝺn) and a gradient of the dopant (ꝺT / ꝺn) for each time increment (t), where the two gradients are ascertained at the interface between crystal and melt in the direction of the normal of the interface to the melt, b) ascertaining a maximum dopant concentration (Cmax) in the melt and c) pulling a single crystal with a dopant concentration less than the ascertained maximum dopant concentration (Cmax), characterized in that a parameter (CS) which is determined by the formula CS = ꝺT / ꝺn - f CS ꝺc / ꝺn is calculated for each time increment t, where the parameter fCS is determined by the product of the average concentration of the dopant (C) in the melt, the density of the silicon melt, the Avogadro constant, the molar mass of silicon and the slope of the liquidus line, and then an average (formula (I)) of the values obtained for the parameter (CS) is formed, where only those values having a (CS) value of less than zero make a contribution, and a maximum dopant concentration (Cmax) is ascertained by adapting the predefined dopant concentration (C) until the amount of (formula (I)) is equal to zero.

The invention belongs to the technical field of element determination, and particularly relates to a method for determining the content of manganese in a manganese source. Comprising the following steps: dissolving a manganese source in a weakly acidic solution with a mass fraction of 4-8%, placing a sample solution on a test board of an automatic potentiometric titrator, adding a reducing agent solution under an acidic condition, adjusting the pH value to a weakly acidic condition, adding a complexing agent solution and a masking agent solution, and carrying out a mixed reaction; testing by adopting an equivalent titration mode, pre-adding an ethylenediaminetetraacetic acid standard titration solution into the pretreated sample solution, mixing, adding a buffer solution to adjust the pH value to 9.5-10.5, dropwise adding an indicator, titrating to the end point by using the ethylenediaminetetraacetic acid standard titration solution, and recording the consumed volume V1; and calculating the manganese content according to the concentration C of the standard titration solution, the consumption volume V1, the mass m of the manganese source and the molar mass M of manganese. Manual operation and subjective judgment errors are reduced, and repeatability and accuracy of results and overall detection efficiency are improved.

The present application relates to the technical field of environmental detection, and particularly relates to a method for determining the molar mass of humic acid in lake water based on three-dimensional fluorescence spectrum, which comprises the following steps: (a) extraction and purification of humic acid in lake water; (b) preparation of a measured solution of humic acid in lake water; (c) selection of the fluorescence peak position in titration experiment; (d) fluorescence quenching titration of humic acid; and (e) calculation of the molar mass of humic acid. The method of the present application only uses conventional laboratory equipment and has low skill requirements for experiment operators. The accuracy and reliability of the method are verified by using model compounds such as tyrosine and standard samples of humic acid.