The determination of ppm to ppb levels of sulfur, oxygen-containing, and certain reactive hydrocarbons in bulk hydrocarbon feedstocks is important in the petroleum and petrochemical industry to minimize catalytic deactivation and improve product quality. Gas chromatography, coupled with selective or ultratrace universal detection (or both), is ideal in most cases for such analysis. However, to enhance selectivity and quantitation at the trace levels, optimized stationary phases are required. These phases are usually of the adsorbent type. This paper summarizes the performance of several state-of-the-art phases for the analyses of trace key hydrocarbons, sulfur, and oxygenated components.