Page 106 - Illustrated Pocket Dictionary of Chromatography

INJECTOR LINER 103

length and inner diameter) such that the plug dimensions resulting
from normal band broadening events never spread the plug enough
for it to reach the column wall. This condition gives higher overall
column efficiency compared with typical injection plugs that are
spread across the column.
injection The event that transfers the sample from a static posi-
tion (e.g., contained in a sample vial or injector loop) outside the
mobile phase. For HPLC and GC the instant an injection occurs is
defined as time zero: t = 0.

injector liner A component of the GC injector housing that is fre-
quently made from glass. Its purpose is to prevent sample contact with
the hot stainless steel surface of the injector. Injector liners are often
partially filled with passivated glass wool. The glass wool acts as a
filter for debris from the septum and other nonvolatile materials that
may get into the injector. Injector liners have different internal con-
figurations that are designed to more effectively handle samples of
varying thermal expansion, etc.

Three examples of GC injector liners are presented. They vary from a long horn
end (top left) to a constricted outlet (top right) to a straight bore (lower middle)
that is wadded with glass wool.