Preventive Maintenance and Troubleshooting
Chromatographic symptoms
126
Peak area discrimination (smaller or larger peaks than expected)
Figure 70. Smaller or larger peaks than expected
You are comparing a chromatogram without needle fractionation against one with
needle fractionation
In the normal injection mode, the automatic liquid sampler uses fast injection
to deliver a representative amount of the sample. Fast injection minimizes
needle fractionation. Without fast injection, sample boils out of the needle.
Chromatograms from manual injection or slower auto injection devices show
higher levels of low molecular weight versus higher molecular materials
because the low boilers boil out of the needle faster than the high boilers.
C
10
CC C C C CC
C
34
36 403014 16 20 25
Automated
injection
Manual
injection
To Next Page
Loading...
Need help?
General
