The drilled Uniliner was designed and developed specifically for making direct injections in an Agilent GC equipped with electronic pressure control (EPC). A hole in the wall of the liner, near the inlet end or the outlet end, equalizes pressure and makes the liner compatible with EPC.
The pneumatics for EPC in the Agilent GC consist of two pressure sensors: one upstream from the injector and one downstream from the injector at the split vent. When a standard Uniliner inlet liner is used for direct injection, it is sealed to the analytical column. Consequently, there is no downstream flow of carrier gas to the pressure sensor at the split vent. A pressure difference between the two sensors is detected, and the upstream sensor overcompensates, causing a high-pressure malfunction and shutdown of the GC. The drilled Uniliner allows a portion of the carrier gas to escape from the liner and equalize the pressure at the two sensors. The drilled Uniliner requires no software or hardware modifications or flow adjustments. For optimum performance, we advise using drilled Uniliner inlet liners in splitless mode.
