BUCHI ELS Detector C-650 - Manual (Page 37)

C-650 Operation Manual, Version B 5 Putting into operation 37
5.9.5 Column noise test
NOTE
When strongly retained compounds are slowly eluted from the column, excessive noise will be
observed.
To determine the column noise:
Turn off the pump and connect the column.
Restart the pump and allow the mobile phase to flow through the system. It is suggested that
you flush the column with a strong solvent for a few minutes before attaching it to the detector.
Set the gain to 12 and monitor the baseline for a few minutes. A suitable column will provide a
baseline that is 20–50 mV above the solvent baseline.
NOTE
If the mobile phase contains acidic modifiers (e.g. CF
3
COOH), disconnect the detector and wash
the Chromatography system for 12 h before starting to analyze unknown samples. This wash
should be performed after the column noise test is completed, but need not to be performed
after each analysis.