Inficon Micro GC Fusion 2-Module Operating Manual page 295

INFICON
11.2.1.3.4 Deformed Peaks
11.2.1.3.4.1 Peak Fronting
074-594-P1H Micro GC Fusion Operating Manual
• The run time is not adequate for all the sample compounds to elute. Compounds
carry over and appear as traveling broad peaks during subsequent runs. This can
be eliminated by increasing Column Temperature or increasing the sample Hold
Time. If applicable, adjust the Backflush Time until all sample components appear
during a run
The ideal chromatography peak is a pure Gaussian shape, although some asymmetry
is always present, particularly near the baseline. Some common types of deformed
peaks are described below.
The peak rises normally, then drops sharply to the baseline.
Fronting is usually caused by column overload. Reduce the sample Inject (ms) time. If
using a variable volume or fixed volume injector, do not reduce the Inject (ms) time to
less than 15 ms to avoid repeatability issues.
Fronting could also result from two (or more) closely unresolved peaks. Decrease the
column temperature by 30°C and repeat the analysis. If peaks separate at the lower
temperature, the fronting was caused by unresolved peaks.
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