ASTM D2129 Test Method for Color of Clear Electrical Insulating Liquids (Platinum-Cobalt Scale)
5. Apparatus
5.1 Color Comparison Tubes - Matched, tail-form Nessler tubes, graduated at the 50-mL mark, and provided with ground-on, optically clear glass caps.
5.2 Color Comparator - A color comparator constructed to permit visual comparison of light transmitted through tail-form Nessler tubes in the direction of their longitudinal axes. The comparator should be constructed so that white light is passed through or reflected off a white glass plate and directed with equal intensity through the tubes, and should be shielded so that no light enters the tubes from the side.
6. Reagents
6.1 Purity of Reagents - Use reagent grade chemicals in all tests. Unless otherwise indicated, all reagents will 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.
6.2 Purity of Water - Use reagent water conforming to Specification D1193.
6.3 Solvent. suitable, clear.
6.4 Cobaltous Chloride (CoCl2·6H2O).
6.5 Hydrochloric Acid (sp gr 1.19) - Concentrated hydrochloric acid (HCI).
6.6 Potassium Chloroplatinate (K2PtCl6).
