# US 2022/0034828 A1 · Method for Measuring Acid Anhydride Content > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2022/0034828 A1 - Document ID: US20220034828A1 - Status: Published application - Kind: A1 - Application number: 17/417,672 - Filed: 2019-12-13 - Published: 2022-02-03 - Earliest claimed: 2018-12-28 - Assignees: Nippon Telegraph and Telephone Corporation - Applicants: Nippon Telegraph and Telephone Corporation - Inventors: Azusa Ishii; Takashi Miwa; Masamitsu Watanabe; Soichi Oka - Web page: https://patentgrep.com/patent/US20220034828A1 ## CPC - G01N 24/08: by using nuclear magnetic resonance (G01N24/12 takes precedence) - G01N 24/088: {Assessment or manipulation of a chemical or biochemical reaction, e.g. verification whether a chemical reaction occurred or whether a ligand binds to a receptor in drug screening or assessing reaction kinetics} - G01R 33/46: NMR spectroscopy - G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q) - G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12) ## Abstract In a first step, a sample formed of a polyester or decomposition products of a polyester is dissolved in a pretreatment liquid containing a secondary amine to obtain a reaction product (amide) of the sample. In a second step, the obtained reaction product, amide, is mixed into a solvent containing deuterated chloroform and deuterated 1,1,1,3,3,3-hexafluoro-2-propanol to fabricate a sample liquid. In a third step, the amount of the amide in the sample liquid is measured through a nuclear magnetic resonance spectroscopy aiming at hydrogen atoms to determine the amount of acid anhydride in the sample. ## Claims ### Claim at position 1 1-6. (canceled) ### Claim 7 A method for measuring an acid anhydride content, the method comprising: a first step of dissolving a sample formed of a polyester or decomposition products of a polyester in a pretreatment liquid containing a secondary amine to obtain a reaction product of the sample; a second step of mixing the reaction product into a solvent containing deuterated chloroform and deuterated 1,1,1,3,3,3-hexafluoro-2-propanol to fabricate a sample liquid; and a third step of measuring an amount of an amide in the sample liquid through a nuclear magnetic resonance spectroscopy aiming at hydrogen atoms to determine an amount of acid anhydride in the sample. ### Claim 8 (depends on 7) The method according to claim 7, wherein two substituents of the secondary amine each comprise an aliphatic hydrocarbon. ### Claim 9 (depends on 8) The method according to claim 8, wherein the two substituents of the secondary amine each comprise the same aliphatic hydrocarbon. ### Claim 10 (depends on 9) The method according to claim 9, wherein the pretreatment liquid further contains chloroform in addition to the secondary amine. ### Claim 11 (depends on 10) The method according to claim 10, wherein a mixing ratio of the chloroform to the secondary amine in the pretreatment liquid is set to 3 or less in a volume ratio. ### Claim 12 The method according to claim ii, wherein, in the first step, the sample is dissolved in the pretreatment liquid to obtain the reaction product by setting a temperature of the pretreatment liquid at 30° C. or higher and at or below a boiling point of a component with a lowest boiling point contained in the pretreatment liquid. ### Claim 13 (depends on 7) The method according to claim 7, wherein, in the first step, the sample is dissolved in the pretreatment liquid to obtain the reaction product by setting a temperature of the pretreatment liquid at 30° C. or higher and at or below a boiling point of a component with a lowest boiling point contained in the pretreatment liquid. ### Claim 14 (depends on 7) The method according to claim 7, wherein the pretreatment liquid further contains chloroform in addition to the secondary amine. ### Claim 15 (depends on 14) The method according to claim 14, wherein a mixing ratio of the chloroform to the secondary amine in the pretreatment liquid is set to 3 or less in a volume ratio. ### Claim 16 (depends on 15) The method according to claim 15, wherein, in the first step, the sample is dissolved in the pretreatment liquid to obtain the reaction product by setting a temperature of the pretreatment liquid at 30° C. or higher and at or below a boiling point of a component with a lowest boiling point contained in the pretreatment liquid. ### Claim 17 A method for measuring an acid anhydride content, the method comprising: dissolving a sample formed of a polyester in a pretreatment liquid containing a secondary amine to obtain a reaction product of the sample; mixing the reaction product into a solvent containing deuterated chloroform and deuterated 1,1,1,3,3,3-hexafluoro-2-propanol to fabricate a sample liquid; and measuring an amount of an amide in the sample liquid through a nuclear magnetic resonance spectroscopy aiming at hydrogen atoms to determine an amount of acid anhydride in the sample. ### Claim 18 (depends on 17) The method according to claim 17, wherein two substituents of the secondary amine each comprise an aliphatic hydrocarbon. ### Claim 19 (depends on 18) The method according to claim 18, wherein the two substituents of the secondary amine each comprise the same aliphatic hydrocarbon. ### Claim 20 (depends on 17) The method according to claim 17, wherein the pretreatment liquid further contains chloroform in addition to the secondary amine, and wherein a mixing ratio of the chloroform to the secondary amine in the pretreatment liquid is set to 3 or less in a volume ratio. ### Claim 21 (depends on 17) The method according to claim 17, wherein dissolving the sample comprises setting a temperature of the pretreatment liquid at 30° C. or higher and at or below a boiling point of a component with a lowest boiling point contained in the pretreatment liquid. ### Claim 22 A method for measuring an acid anhydride content, the method comprising: dissolving a sample formed of one or more decomposition products of a polyester in a pretreatment liquid containing a secondary amine to obtain a reaction product of the sample; mixing the reaction product into a solvent containing deuterated chloroform and deuterated 1,1,1,3,3,3-hexafluoro-2-propanol to fabricate a sample liquid; and measuring an amount of an amide in the sample liquid through a nuclear magnetic resonance spectroscopy aiming at hydrogen atoms to determine an amount of acid anhydride in the sample. ### Claim 23 (depends on 22) The method according to claim 22, wherein two substituents of the secondary amine each comprise an aliphatic hydrocarbon. ### Claim 24 (depends on 23) The method according to claim 23, wherein the two substituents of the secondary amine each comprise the same aliphatic hydrocarbon. ### Claim 25 (depends on 22) The method according to claim 22, wherein the pretreatment liquid further contains chloroform in addition to the secondary amine, and wherein a mixing ratio of the chloroform to the secondary amine in the pretreatment liquid is set to 3 or less in a volume ratio. ### Claim 26 (depends on 22) The method according to claim 22, wherein dissolving the sample comprises setting a temperature of the pretreatment liquid at 30° C. or higher and at or below a boiling point of a component with a lowest boiling point contained in the pretreatment liquid.