In the early days of comprehensive two-dimensional gas chromatography (GC × GC), modulators were generally based on analyte trapping in the stationary phase of a segment of a capillary column.While these modulators provided the proof of concept and produced some excellent separations, they suffered from a number of drawbacks, including limited range of GC oven temperatures and less than stellar robustness.Consequently, the advent of cryogenic modulators was considered a big step forward.Cryogenic modulators trap the analytes at subambient temperatures, and release them at or near the oven temperatures.Their performance is usually very good, and so is their robustness.However, as commercial cryogenic modulators began to appear, it gradually became clear that they also have limitations, the biggest of which is probably the high operating cost related to the large consumption of the cryogenic agent.In addition, many potential users are discouraged by the perceived complexity of the systems.