1.1 本试验方法包括以乙酸形式测定酸度（见规范 D4806 )常见的变性乙醇等级，以及乙醇与E95至E30汽油的混合物。本试验方法用于测定低于200℃的低酸度 mg/kg（ppm质量），不包括二氧化碳。 1.1.1 程序A- 专门用于通过电位滴定法测量酸度。这是裁判的方法。 1.1.2 程序B- 专为通过颜色终点滴定法测量酸度而开发。 1.2 乙醇和乙醇混合物可通过本试验方法直接分析，无需任何样品制备。 1.3 查看当前和适当的材料安全数据表（MSDS），了解有关毒性、急救程序、安全预防措施和适当个人防护设备的详细信息。 1.4 以国际单位制表示的数值应视为标准值。本标准不包括其他计量单位。 1.5 本标准并非旨在解决与其使用相关的所有安全问题（如有）。本标准的用户有责任在使用前制定适当的安全、健康和环境实践，并确定监管限制的适用性。 第节给出了一些具体的危害说明 7. 关于危险。 1.6 本国际标准是根据世界贸易组织技术性贸易壁垒（TBT）委员会发布的《关于制定国际标准、指南和建议的原则的决定》中确立的国际公认标准化原则制定的。 ====意义和用途====== 5.1 本试验方法定量测量乙醇或乙醇混合物中的酸度。变性燃料乙醇可能含有防腐剂和洗涤剂等添加剂，以及制造过程中可能影响成品乙醇燃料酸度的污染物。 低分子量有机酸（如乙酸）的极稀水溶液对许多金属具有高度腐蚀性。将这种酸保持在非常低的水平很重要。 5.2 乙醇或乙醇混合物中可接受的酸度水平可能因不同规格而异，但通常低于200 mg/kg（ppm）。为了确定产品质量是否符合规范，可能需要了解酸度。

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 Procedure A— Developed specifically for measurement of acidity by potentiometric titration. This is the referee method. 1.1.2 Procedure 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use. Some specific hazards statements are given in Section 7 on Hazards. 1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee. ====== 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.