Abstract
A sensitive gas chromatograph of the reduced-pressure type was devised to analyze hydrogen nuclear spin isomers and isotopes, and its characteristics were studied in order to obtain the optimum conditions for analysis. It was shown that the para and ortho composition of 0.01 ml. S. T. P. of normal hydrogen could be determined within an accuracy of 1% by employing an alumina column cooled at −196°C, while the composition of 0.02 ml. S. T. P. of the equilibrated mixture of hydrogen, hydrogen deuteride and deuterium at 25°C could be determined within the same accuracy by employing an alumina column coated with manganese chloride. The alumina column was no longer capable of separating the spin isomers when it was treated above 350°C. Kinetic studies of the hydrogen-deuterium equilibration (21°C) and of the orthohydrogen conversion (−196°C), using the alumina as a catalyst, revealed that this strong activation creates active sites for the equilibration and the magnetic conversion which makes the peak separation obscure. The nature of these active centers was briefly discussed.