We describe the effect of a modified gas chromatography-atomic emission detection (GC-AED) instrumental setup on the analysis of organometallic compounds. It is shown that the installment of an additional makeup gas flow positively effects the performance of the Hewlett Packard (HP) atomic emission detector. In addition, a partially sealed transfer line capillary end providing a narrowed central flow substantially improved the sensitivity. Lower detectable levels were achieved for several of the investigated elements. The parameters makeup gas flow, additional makeup gas flow, and transfer line outlet diameter were optimized and their effects on the peak shapes and detectable levels were evaluated. GC-AED analysis was performed for the first time for the speciation of volatile metal-containing compounds present in diesel particulate matter. Compounds containing iron, chromium, and manganese were successfully detected. © 1996 John Wiley & Sons, Inc.