A hot-extraction high-vacuum technique, involving mass-spectrographic detection, was used to determine the H content of U. The time-dependences of H evolution from the bulk and of surface contamination were sufficiently different to separate. During the transient temperature portion of the analysis, the H evolution rate was strongly influenced by the solubility of H. The H content which was due to surface contamination was equal to about 0.5ppm[wt]. This limited the lower limit of detection, for bulk H, to 0.05ppm[wt]. Diffusion data for H in U were deduced from the H evolution rates (table 307).

G.L.Powell, J.B.Condon: Analytical Chemistry, 1973, 45[14], 2349-54