A simple and sensitive separation and preconcentration technique for the determination of trace amounts of cadmium, cobalt, copper, nickel and lead in chemical grade potassium salts is described. Analytes were complexed with 1-nitroso-2-naphthol at pH 6. Following solid-phase extraction on Amberlite XAD-4 resin, metals were determined by flame atomic absorption spectrometry. The recoveries of metal ions were greater than 95 %. The detection limits were between 16 ng/L (Cd) and 59 ng/L (Ni). The relative standard deviation (RSD) of the determinations varied from 1 to 7 %.