INFICON 3000 Micro GC Gas Analyzer Operating Manual - Manual (Page 245)

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3000 Micro GC Operating Manual
9.2.1.4.3 Deformed Peak Apex
Top (apex) of the peak is deformed.
Figure 9-3 Deformed apex
A deformed peak apex is usually caused by column overloading. In severe
cases, doubling the amount injected may cause little or no increase in peak
size. Decrease the sample volume. Since the detector is at the upper limit of its
response, a substantial reduction in sample volume is needed to return to
normal operating range.
9.2.1.4.4 Split Peak Apex
Top (apex) of the peak is split.
Figure 9-4 : Apex split
Make sure that this is not a merged peak by conducting a run at a lower
temperature.
Decrease volume of sample injected by a factor of ten and repeat the run. If the
split disappears, detector overload was the problem. This usually improves
linearity as well.
Hydrogen peaks, analyzed with a thermal conductivity detector and helium
carrier, often show a split peak apex. Reduce sample size until the split is
resolved.