ASTM D5798 Standard Specification for Ethanol Fuel Blends for Flexible-Fuel Automotive Spark-Ignition Engines
7. Sampling, Containers, and Sample Handling
7.1 The reader is strongly advised to review all intended test methods prior to sampling to better understand the importance and effects of sampling technique, proper containers, and special handling required for each test method.
7.2 Correct sampling procedures are critical to obtain a sample representative of the lot intended to be tested. Use appropriate procedures in Practice D4057 for manual method sampling and in Practice D4177 for automatic sampling, as applicable.
7.3 The correct sample volume and appropriate container selection are important decisions that can impact test results. Refer to Practice D4306 for aviation fuel container selection for tests sensitive to trace contamination. Refer to Practice D5854 for procedures on container selection and sample mixing and handling. Where practical, ethanol fuel blends should be sampled in glass containers. If samples must be collected in metal containers, do not use soldered metal containers. The soldering flux in the containers and the lead in the solder can contaminate the sample. Plastic containers should be avoided.
7.4 A minimum sample size of about 1 L (1 U.S. qt) is recommended.
8. Test Methods
8.1 Determine the requirements enumerated in this specification in accordance with the test methods listed in Table 1. The scope of some of the test methods listed below does not include ethanol fuel blends. The precision of these test methods can differ from the reported precisions when testing ethanol fuel blends.
8.1.1 Ethanol Content - Test Method D5501.
8.1.2 Vapor Pressure - Test Method D4953 or D5191.
8.1.3 Acidity - Test Method D7795.
8.1.4 pHe - Test Method D6423.
8.1.5 Gum Content, Solvent Washed and Unwashed - Test Method D381.
8.1.6 Inorganic Chloride Content - Test Methods D7319 or D7328.
8.1.7 Water Content - Test Method E203, E1064, or D7923.
8.1.8 Copper Content - Modification of Test Method D1688.
8.1.8.1 The modifications of Test Method D1688, Test Method A (atomic absorption, direct) consists of mixing reagent-grade ethanol (which may be denatured in accordance with TTB Formula 3A or 30) in place of water as the solvent of diluent for the preparation of reagents and standard solutions. However, this shall not be done to prepare the stock copper solution described in the section on Copper Solution, Stock in Test Method D1688. Because a violent reaction can occur between the acid and the ethanol, use water, as specified, in the acid solution part of the procedure to prepare the stock copper solution. Use ethanol for the rinse and final dilution only.
8.1.9 Sulfur Content - Test Method D5453 or D7039.
8.1.10 Methanol Content - Test Method D5501.
9. Keywords
9.1 acidity; alcohol; automotive spark-ignition engine fuel; chloride; copper corrosion; E85; ether; ethanol fuel blends for flexible-fuel automotive spark-ignition engines; flexible-fuel; hydrocarbon; hydrocarbon blendstock; inorganic chloride; lead; MTBE; oxidation stability; oxygenates; pHe; phosphorus; solvent washed gum content; sulfur; vapor pressure; volatility; water
