ASTM D525 Test Method for Oxidation Stability of Gasoline (Induction Period Method)
8. Sampling
8.1 Sample in accordance with the procedure for oxidation stability as described in Practice D4057.
9. Preparation of Apparatus
9.1 Wash the glass sample container with gum solvent until free from gum. Rinse thoroughly with water and immerse the sample container and cover in a mildly alkaline or neutral pH laboratory detergent cleaning solution. The type of detergent and conditions for its use need to be established in each laboratory. The criterion for satisfactory cleaning shall be a matching of the quality of that obtained with chromic acid cleaning solutions (or some other equivalently strong oxidizing non-chromium containing acid cleaning solutions) on used sample containers and covers (fresh chromic acid, 6-h soaking period, rinsing with distilled water and drying). For this comparison, visual appearance and mass loss on heating the glassware under test conditions may be used. Detergent cleaning avoids the potential hazards and inconveniences related to the handling of highly corrosive and strongly oxidizing acid solutions; this procedure remains the reference cleaning practice and as such may function as an alternate to the preferred procedure, cleaning with detergent solutions.
9.2 Remove container and cover from the cleaning solution by means of corrosion-resistant steel forceps and handle only with forceps thereafter. Wash thoroughly, first with tap water, then with distilled water, and dry in an oven at 100 to 150°C for at least 1 h.
9.3 Drain any gasoline from the pressure vessel and wipe the inside of the pressure vessel and pressure vessel closure, first with a clean cloth moistened with gum solvent and then with a clean dry cloth. Remove the filler rod from the stem and carefully clean any gum or gasoline from the stem, rod, and needle valve with gum solvent. The pressure vessel, the valve, and all connecting lines shall be thoroughly dry before each test is started.
NOTE 6 - Caution: Volatile peroxides which may have formed during a previous test may accumulate in the equipment, producing a potentially explosive environment. Special care in cleaning after each test is needed to ensure the filler rod, stem, and needle valve are free of these peroxides.
