1982 Volume 31 Issue 9 Pages 523-528
Microamounts of carbon dioxide could be determined by the coulometric titration after conversion to ammonia with sodium amide containing some sodium hydroxide. The process was previously used only for the determination of microamounts of water and hydrogen. Both carbon dioxide and water could be determined after separation with a cold trap cooled at about -70 °C, and the method was applied to the trace characterization of gaseous materials evolved from heated polyethylenes and Teflon [poly(tetrafluoroethylene)]. The amounts of water evolved from hard (plate) and soft (tube) type polyethylenes heated at 120 °C for 1 h were 48.4 ppm and 9.9 ppm respectively. Carbonaceous materials began to evolve at 80 °C for the former and at 90 °C for the latter. Therefore, the former material was less satisfactory for containers and laboratory wares, especially for the samples for the microdetermination of carbon. Teflon rod liberated only traces of water and organic compounds at 130 °C. Carbonaceous contaminators on the surfaces of Zircaloy metals were also determined by this method. The samples were heated at 100 °C and 500 °C. The carbonaceous materials were mainly found by heating the sample at 500 °C, and were considered as rather heavy (high molecular weights) organic compounds. Simple ultrasonic washing with some organic solvents was not enough to remove the materials, and the washing procedure first with 2 N nitric acid was more effective to remove them thoroughly.
