In our research, we make extensive

In our research, we make extensive use of a device that we have patented, called the longitudinally modulated cryogenic system (LMCS; refs 52, 55, 57, 60, 61) – Figure 2. This device is a cold – cryogenically cooled – cylinder that in one operational mode oscillates back and forth along the capillary GC column. Alternatively the column can move back-and-forth within the cryotrapping zone. It is essentially a trapping device that acts somewhat like a gate. Volatile compounds cannot pass the gate until the device moves relative to the column (in this case, towards the incoming carrier flow), so that compounds trapped at the cold spot can then be heated and released into the gas phase.