A method for the simultaneous determination of Mn, Co, Zn and Ni which combines Ion-chromatography and a post column reaction with xylenol orange is described. Using 0.07 M oxalic acid (pH adjusted to 5.5 with lithium hydroxide) as eluent, Mn, Co, Zn and Ni were first separated on a 4x250mm IonpacCS-5 column having both sulphonic acid and Alkyl quaternary ammonia functional groups and then transferred to a post-column reaction coil, where the elements react with xylenol orange. The coloured complexes formed were spectrophotometrically measured at 570 nm. The procedure has been successfully applied for the determination of Co, Zn and Ni in Al-bronze.