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3.3 Analysis using capillary column
3
Installation to injection port
1
Prepare glass insert.
• There are 3 types of glass insert: for split analysis,
splitless/WBI analysis, and for packed column.
• Use an insert that has undergone deactivation
treatment when injecting samples of high-
resolvability and high-sorbability, or samples of low
concentration.
2
Pack silica wool.
Silica wool
It is necessary to pack silica wool to mix the
vaporized samples sufficiently.
Also, it prevents high-boiling point compounds from
contaminating capillary column.
Amount
Position
If you place silica wool 1 to 2 mm below the needle tip
position at injection, you can obtain the highest
reproducibility. However, since the reproducibility is
degraded if there are variations in how sample
solution flies from the tip, it is absolutely crucial to
maintain the syringe condition all the time.
Meanwhile, if you place the wool where the needle tip
sticks 4 mm deep, even though you cannot expect
reproducibility to be as high as in the case of vapor
application, the reproducibility is not affected by the
variation in how the solution flies.
In split analysis using GC-2014, the latter position is
recommended.
20 mm 25 mm
5.5 mm
Silica wool
For split For splitless/W.B.I.
Insert type
Wool amount
(mg)
Split Approx. 10
Splitless/WBI Approx. 2
Direct injection for wide bore column None
Direct injection for wide bore column
(When sample contains non-volatile
compounds)
5 or less
For particular samples, you may obtain better results by
adjusting the amount of silica wool in the insert.
• For highly absorptive samples (e.g. agricultural
samples), reduce the amount.
• For the sample whose solvent keeps high latent heat
of evaporation (e.g. water), increase the amount.
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