This standard refers to the international standards ISO 1393-1977 "Determination of acidity of industrial liquid halogenated hydrocarbons-Titration method", ISO 2887-1987 "Industrial sec-butanol , methyl ethyl ketone , isobutyl ketone, isoamyl ethyl ketone, diacetone alcohol Determination of acidity of ethylene glycol and phenolphthalein as indicator-Volumetric method", GM13 "acidity and alkalinity" in ISO6353/1-1982 "Chemical Analysis Reagents-Part 1: General Test Methods"
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1 Subject content and scope of application
This standard specifies test methods for the determination of acidity and alkalinity of organic chemical products by volumetric analysis
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This standard applies to the determination of the content of acid or alkaline substances in the form of impurities in organic chemical products.
This content is called acidity or alkalinity.
When this standard is used to determine the acidity and alkalinity of organic chemical products, the alkali standard titration solution or The titration volume of the acid standard titration solution shall not be less than 0.
01 mL
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2 Reference standards
Preparation of standard solution for GB601 chemical reagent titration analysis (volume analysis)
Preparation of preparations and products used in GB603 chemical reagent test method
GB6682 Analysis and experiment air water specifications and test methods
3 Test method
Unless otherwise noted, all reagents used in this standard are analytical reagents
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The standard titration solutions, preparations and products used in this standard shall be prepared in accordance with the provisions of GB601 and GB603 unless other requirements are specified
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The water used in the laboratory should comply with the second grade water specification in GB 6682
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3.
1 Determination of acidity and alkalinity of standard titration solution with water as medium
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1.
1 Method summary
After the sample is properly processed, under the specified operating conditions, add an indicator and titrate with an alkali standard titration solution or an acid standard titration solution to calculate the acidity or alkalinity of the sample
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1.
2 Reagents and solutions
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1.
2.
1 The concentration c(H + ) of the standard titration solution of hydrochloric acid or sulfuric acid shall not be less than 0.
01 mol/L .
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1.
2.
2 sodium hydroxide standard titration solution concentration C (OH - ) not less than 0.
01mol / L,
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1.
3 Apparatus
General laboratory instruments and semi-micro burettes, with a scale of 0.
10 mL; or micro burettes with a scale of 0.
02 mL
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4 Analysis steps
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4.
1 Titration with aqueous medium as the extraction solvent
Add a certain volume of carbon dioxide- free water and the specified indicator to the vial, and titrate to the end point with an alkali standard titration solution or an acid standard titration solution, excluding the volume of the consumed standard titration solution
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Immediately transfer the neutralized water to the separatory funnel and add the specified amount of sample, shake well, separate the water layer after layering, add an appropriate amount of indicator, and titrate with maple standard titration bath solution or acid standard The solution is titrated to the end point
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Record the volume of standard titration solution consumed
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For the sample that can be titrated directly after adding the aqueous medium to the sample, add the specified amount of the sample to the neutralized water, shake it thoroughly, mix it, and let it stand for a while, then directly titrate it with an alkali standard titration solution or an acid standard titration solution To the end
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Record the volume of standard titration solution consumed
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1.
4.
2 Titration when the extraction solvent is an organic medium
Add a certain organic medium and indicator in a prescribed volume into the Erlenmeyer flask, and titrate to the end point with an alkali standard titration solution or an acid standard titration solution, excluding the volume of the consumption standard titration solution
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Transfer the neutralized organic medium to the separatory funnel and add the specified amount of sample, vibrate fully, stand still for layering, separate the extracted organic medium layer, add an appropriate amount of indicator, and perform the specified operation Under the conditions, use alkali standard titration solution or acid standard titration solution to titrate to the end point
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Record the volume of standard titration solution consumed
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For samples that can be titrated directly after adding organic medium.
Add the specified amount of sample to the neutralized organic medium, shake it thoroughly, mix well, let it stand for a while, and titrate with an alkali standard under the specified operating conditions Titrate the solution or acid standard titration solution to the end point, and record the volume of the standard titration solution consumed
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