ASTM D1093 for Acidity of Hydrocarbon Liquids and Their Distillation Residues
6. Apparatus
6.1 Centrifuge Tube, cone-shaped, 100-mL capacity; calibration not necessary.
6.2 Centrifuge, capable of swinging two centrifuge tubes at 1500 rpm.
NOTE 2 - Apparatus used for Test Method D91 is satisfactory.
7. Reagents
7.1 Purity of Reagents - Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all reagents shall conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society, where such specifications are available. Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high purity to permit its use without lessening the accuracy of the determination.
7.2 Purity of Water - Unless otherwise indicated, references to water shall be understood to mean reagent water conforming to Type IV Specifications D1193.
7.3 Ethanol (95 %) (Warning - See Note 3.) - Either pure grain or denatured with 5 % methanol.
NOTE 3 - Warning: Flammable, Vapor Harmful, if denatured it cannot be made non-toxic.
7.4 Methyl Orange Indicator Solution (1 g/L) - Dissolve 1.0 more or less 0.1 g of methyl orange in water and dilute to 1 L.
7.5 Phenolphthalein Indicator Solution - Dissolve 1.0 more or less 0.1 g of phenolphthalein in 100 mL of alcohol. Add sodium hydroxide solution (NaOH, 0.8 g/L) dropwise to develop a very faint pink color.
8. Sampling
8.1 Using Practice D4057 (manual sampling) or Practice D4177 (automatic sampling) as a guideline, ensure that a sample representative of the material to be tested is obtained.
