Gas Chromatography (GC) (IUPAC Compendium of Chemical Terminology):
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Lecture 3. <strong>Gas</strong> chromathography.<br />
Comparison <strong>of</strong> different injection methods.<br />
Solvent<br />
A<br />
Solvent<br />
B<br />
3<br />
2 3<br />
2<br />
Split injection<br />
Split vent closed<br />
3<br />
Solvent<br />
C<br />
Solvent<br />
2<br />
D<br />
2<br />
3<br />
Split vent opened<br />
after 30 s<br />
Solvent trapping<br />
A: standard Split injection, peaks are sharp.<br />
B: split vent closed, injection liner was purged slowly, sample was applied over a long time,<br />
peaks are broad and tail badly.<br />
C: same as B, but split vent was opened after 30 s to rapidly purge all the vapors from the<br />
injector liner.<br />
D: same as C, but the column was initially cooled to r.t. to trap solvent and solutes; to be<br />
proper splitless injection, the sample should be much more diluted.<br />
25
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