12 Injection Port
12.6
12.
141
GC-2010 Plus
12.6Direct Injection System
Q Direct injection system
The direct injection system is an analysis method where a wide-bore column is connected to
the injection port and almost the entire amount of the injected sample is injected into the col-
umn. For the direct injection system, a WBI (wide-bore injection) injection port is used.
In the direct injection system, a wide-bore (0.53 mm or greater) column is usually used.
Analysis needs to be performed with a column flow rate larger than the value optimum for
separation. Therefore, separation is not as good as analysis where a capillary column with a
narrower bore is used. However, analysis is often performed with a relatively higher sensitiv-
ity because more sample can be injected into the column as compared to split analysis.
Also, the analysis method can be changed to capillary column analysis relatively easily
because there is no limit on column temperature conditions and separation conditions of a
packed column can be easily traced. However, peak shapes are broader as compared to
analysis using a capillary column with a narrower bore. Thus, S/N ratio may not necessary
be higher even when peak area is greater in some analysis conditions.
Fig. 12.6.1
Control
CARRIER
PURGE
PURGE VENT
Capillary column
Control
TFC
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