We have verified the suitability of different sulphur-containing complexing reagents for the HPLC separation of ionic lead and mercury compounds with subsequent photometric detection. For the optimization of the separations, different parameters, e.g. the pH value of the mobile phase, were varied and their influence on the retention of the species determined. For the first time on-column derivatization with mercaptoethanol was used for the separation of lead compounds. Based on the optimized chromatographic conditions, an on-line enrichment system was developed with recoveries between 75 and 88%. The use of methyl thioglycolate as the second complexing reagent made it possible to determine all analytes, organolead and organomercury compounds, simultaneously. Finally, both methods are compared briefly.