AbstractThe conversion of a commercial vapour fractometer to operate with capillary columns is described.This apparatus was used with a squalane stationary phasepat 100°, to examine several kerosene‐type solvents which have already been used, or which might be used in the future, as inert diluents for TBP extraction systems.Several chromatograms are presented and discussed and these serve to demonstrate the remarkable potentialities of capillary columns and ionisation detectors for work of this natu