US EPA Method 8270D specifies a procedure for the determination of semivolatiles in solid waste and ground water samples. The long list of analytes includes compounds of a variety of functionalities. A 30 m x 0.25 mm I.D. column is commonly used for the analysis. Sometimes, a thicker phase film, such as a 0.25 mm I.D. x 0.50 μm df, is appropriate to accommodate higher concentrations. In this application, the analysis was done on a column with a similar phase ratio, but of shorter length and a narrower I.D. (20 m x 0.18 mm I.D., 0.36 μm). The higher efficiency in terms of plates/meter of the 0.18 mm I.D. over a 0.25 mm I.D. column allowed for a shorter analysis time on the 20 m length while maintaining critical resolutions.