AbstractAlumina‐coated porous layer open tubular (PLOT) columns are widely used for analyses of light hydrocarbons (C1to C6). There is, however, a need for improved selectivity for complex analyses such as the determination of impurities in high purity petrochemical products. Some commercial alumina PLOT columns do not have sufficient selectivity for such analyses. The selectivity of four commercial alumina PLOT columns is evaluated for analyses of propylene and ethylene, and differences in column selectivity discussed. Requirements of column selectivity and retention are presented for several applications including the analysis of refinery gas, transformer oil gas, and fuel ga