RESULTS Thin Layer Chromatography. Initial samples of thioTEPA dissolved in water gave a series of spots on the chromatogram (Fig. ib) the Rf values of which are given in Table l. These same spots with the exception of spot 5 were present on chromatograms of a sample of thioTEPA dissolved in methanol or chloroform (Fig, la) and also appeared on repeated application of substance isolated from a plate in the region of spot 4 corresponding to ...