ASTM D7795 - 12

    Standard Test Method for Acidity in Ethanol and Ethanol Blends by Titration

    Active Standard ASTM D7795 | Developed by Subcommittee: D02.06

    Book of Standards Volume: 05.04


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    Significance and Use

    5.1 This test method measures acidity in ethanol or ethanol blends quantitatively. Denatured fuel ethanol may contain additives such as corrosion inhibitors and detergents as well as contaminants from manufacturing that can affect the acidity of finished ethanol fuel. Very dilute aqueous solutions of low molecular mass organic acids, such as acetic acid, are highly corrosive to many metals. It is important to keep such acids at a very low level.

    5.2 Acceptable levels of acidity in Ethanol or Ethanol blends can vary with different specifications but in general it is below 200 mg/kg (ppm). Knowledge of the acidity can be required to establish whether the product quality meets specification.

    1. Scope

    1.1 This test method covers the determination of acidity as acetic acid (see Specification D4806) in commonly available grades of denatured ethanol, and ethanol blends with gasoline ranging from E95 to E30. This test method is used for determining low levels of acidity, below 200 mg/kg (ppm mass), with the exclusion of carbon dioxide.

    1.1.1 Test Method A—Developed specifically for measurement of acidity by potentiometric titration. This is the referee method.

    1.1.2 Test Method B—Developed specifically for measurement of acidity by color end point titration.

    1.2 The ethanol and ethanol blends may be analyzed directly by this test method without any sample preparation.

    1.3 Review the current and appropriate Material Safety Data Sheets (MSDS) for detailed information concerning toxicity, first aid procedures, and safety precautions and proper personal protective equipments.

    1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

    1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. Some specific hazards statements are given in Section 7 on Hazards.


    2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.

    ASTM Standards

    D770 Specification for Isopropyl Alcohol

    D1193 Specification for Reagent Water

    D4175 Terminology Relating to Petroleum, Petroleum Products, and Lubricants

    D4806 Specification for Denatured Fuel Ethanol for Blending with Gasolines for Use as Automotive Spark-Ignition Engine Fuel

    D6300 Practice for Determination of Precision and Bias Data for Use in Test Methods for Petroleum Products and Lubricants

    E200 Practice for Preparation, Standardization, and Storage of Standard and Reagent Solutions for Chemical Analysis


    ICS Code

    ICS Number Code 75.160.20 (Liquid fuels)

    UNSPSC Code

    UNSPSC Code 15101506(Gasoline or Petrol)


    Referencing This Standard

    DOI: 10.1520/D7795-12

    ASTM International is a member of CrossRef.

    Citation Format

    ASTM D7795-12, Standard Test Method for Acidity in Ethanol and Ethanol Blends by Titration, ASTM International, West Conshohocken, PA, 2012, www.astm.org

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