When compared to the exacting attention that gas chromatographers pay the analytical column, it often seems that the inlet septum receives relatively little consideration. In fact, many chromatographers are surprised to discover that GC instrument manufacturers recommend daily inspection and/or replacement of the inlet septum to maximize instrument performance. Although inexpensive compared to other chromatography consumables, a freshly replaced septum is essential for maintaining system isolation from the outside environment.
A poorly maintained inlet will cause the instrument to suffer from diminished sensitivity, shifting response factors, asymmetrical peak shapes, and an overall poorer precision and accuracy compared to a well-maintained one. When older, damaged septa are cored by the syringe needle these cores of septa can drop into the inlet liner, blocking the flow of gas and releasing bleed volatiles onto the column. Such detriments impact system sensitivity and inevitably result in unscheduled maintenance and more frequent calibrations.
This technical note outlines the inlet septum replacement procedure for the capillary split/splitless (CAP) injector (Item #: N6120146) for the Clarus® 590/690 GC platform.