GCxGC (“GC by GC”), also known as Comprehensive Two-Dimensional Gas Chromatography, is a powerful analytic technique that utilizes two columns of differing phase selectivity connected by a modulation device. The set-up of GCxGC improves peak capacity, resolution, and detectability. On average, a GCxGC analysis has five times the sensitivity and gains three times the number of compound identifications of typical GC-MS runs.