ASTM D6422 Standard Test Method for Water Tolerance (Phase Separation) of Gasoline-Alcohol Blends
6. Apparatus (see Fig. 1)
6.1 Test Container - The test container must be made of clear, cylindrical glass, with a flat bottom, that has a 33.2 to 34.8-mm outside diameter, a 30 to 32.4-mm inside diameter, a wall thickness no greater than 1.6 mm, and a height between 115 to 125 mm. The jar shall be marked with a line to indicate the test specimen height 54 +/- 3 mm above the inside bottom. The specification conforms to the test jar identified in Test Method D2500.
6.2 Thermometer - ASTM thermometer 6C (range -80 to +20°C, with 1°C graduations, 76-mm immersion) meeting the requirements in Specification E 1. A thermometer mounted to pass through the stopper must be provided for each test container.
6.3 Viton Rubber Stopper - A stopper of appropriate dimensions to snugly fit the test container, bored centrally for the test thermometer. Other suitable types of rubber stoppers may be substituted for the Viton rubber stoppers.
6.4 Jacket, made of metal or glass, watertight, cylindrical, flat bottom, about 115 mm in depth, with an inside diameter of 44.2 to 45.8 mm. It must be supported free of excessive vibration and supported firmly in a vertical position in the cooling bath specified in 6.7 so that no more than 25 mm projects out of the cooling medium.
6.5 Disk, made of cork or felt, 6 mm in thickness, to fit loosely on the inside bottom of the jacket.
6.6 Gasket - A ring form, about 5 mm in thickness, to fit snugly around the test container and loosely inside the jacket. The gasket may be made of rubber, leather, or other material that is elastic enough to cling to the test container and hard enough to hold its shape. Its purpose is to prevent the test container from touching the jacket.
6.7 Cooling Baths, maintained at prescribed temperatures with a firm support to hold the jacket vertically, capable of reducing the test specimen temperature to -42°C (-44°F) for the test analysis, similar to that specified in 6.7 of Test Method D2500. The required bath temperatures may be maintained by refrigeration, if available, otherwise by suitable freezing mixtures, such as a dry ice-isopropyl alcohol bath.
6.8 Pipettes (optional), disposable or volumetric, for rinsing and transferring test specimens into the test container.
7. Reagents and Materials
7.1 Acetone - Technical grade acetone is suitable for use in the cooling baths, provided it does not leave a residue on drying.
NOTE 1 - Warning: Extremely flammable.
7.2 Carbon Dioxide (Solid) or Dry Ice - A commercial grade of dry ice is suitable for use in the cooling baths.
NOTE 2 - Warning: Extremely cold (-78.5°C). Avoid direct contact with the skin.
7.3 Isopropyl Alcohol (2-propanol) - A commercial grade of dry isopropyl alcohol is suitable for use in the cooling baths.
NOTE 3 - Warning: Flammable.
7.4 Methyl Alcohol - A commercial or technical grade of dry methyl alcohol is suitable for use in the cooling baths.
NOTE 4 - Warning: Flammable. Vapor harmful. Toxic.
8. Sampling and Handling
8.1 Draw samples in accordance with the instructions in Practice D4057. Draw samples into 1 L (1 qt) clear glass containers. Fill container 70 to 80 % with sample to allow the user of the test method an opportunity to visually inspect the sample for cleanliness, free water, or impurities before proceeding with the test. In the event a sample is to be taken from a retail type dispenser prior to analysis, use the nozzle sampling procedure described in Practice D5842 in place of the instructions in Practice D4057.
NOTE 5 - Paragraph 6.4.2 of Practice D 4306 does not recommend the use of borosilicate glass bottles for water separation testing of aviation fuels, but rather recommends the use of epoxy-lined cans. Gasoline-alcohol sample matrices are quite different than aviation fuels and therefore Practice D4306 is not applicable or appropriate. The use of clear glass containers does not compromise the sample integrity of gasoline-alcohol blend samples for analyses and allows visual inspection of samples that would not be possible if epoxy-lined cans were used.
8.2 Samples shall not be chilled during storage so as to prevent possible phase separation prior to testing, that may be irreversible upon warming. Store samples at ambient temperature.
8.3 Because gasoline-alcohol blends are hygroscopic, as well as volatile, minimize contact with the atmosphere by keeping the sample containers tightly closed except when transferring the sample.
