Agilent J&W CP-Al2O3/Na2SO4 and KCl are an aluminum oxide PLOT columns that offer high selectivity for separating ppm levels of C1-C5 hydrocarbons in a main stream of C1-C5 hydrocarbons. The Na2SO4 deactivation salt provides a polar Al2O3 surface, so that unsaturated compounds such as ethylene and acetylene are retained longer. These columns analyze more compounds in a single run than packed columns, while still delivering higher resolution and faster analysis times. When compared to liquid stationary phases, CP-Al2O3 provides increased selectivity and allows all C1-C5 hydrocarbon isomers to be separated. CP-Al2O3 operates without the need for sub-ambient cooling.