The idea to use high performance liquid chromatography with continuous UV detection for multi-element radiochemical separation and simultaneous multi-element on-line yield determination is introduced. The validity of the concept was evaluated by demonstrating the constancy of the ratio of the signals for a main isotope (60Co) and a carrier (59Co) as a function of the elemental mass processed in the separation. The suitability of the method for practical purposes is demonstrated by its application to the RNAA determination of cobalt in biological materials. It is concluded that the method, although not yet completely developed, bears the potential of improving both accuracy and precision of multi-element RNAA.