Gas Chromatography (GC) (IUPAC Compendium of Chemical Terminology):

Lecture 3. Gas chromathography.
On-Column injection.
Used for samples that decompose above their boiling point.
Preferred for quantitative analysis.
Syringe needle
1 ml/min
0 ml/min
0 ml/min
At initial oven temperature, e.g. 50ºC
1ml/min
Solution is injected directly into column, without going through a hot injector.
Initial column temperature is low enough to condense solutes in narrow zone. Warming the
column initiate chromatography.
The special thin-needle syringe is required to use good resolution columns (column diameter
0.2 - 0.32 mm).
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Advantages of on-column injection:
narrow peaks of analyte;
good accuracy and precision for quantitative analysis;
no thermal destruction of the sample;
little loss of high-boiling components.
Drawbacks:
non-volatile impurities harm the column;
shape of the peaks depends on solvent.
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