11.
Resolution problems
Resolution is the ratio
of center-to-center separation between two peaks (the difference in
retention times) to the average baseline widths of those peaks.
Therefore, a decrease in resolution implies that either selectivity or
peak width has changed.
Choose the one of the following which best describes the type of change
which caused your resolution problem:
1. Selectivity
and/or retention time changes
The retention time of one or more of your
peaks is out of specification.
2. Abnormally
wide peaks (abnormally low plate count)
The retention times
and symmetries of all your peaks are within specification, but the width or plate count of one or more of your
peaks is out of specification.
3. Peak shape
problems
A. Tailing
peaks
The retention times
of all your peaks are within specification, but the peak symmetry (asymmetry factor or tailing factor) of one or more of your
peaks is out of specification.
B. Peaks
with shoulders
The retention times
of all your peaks are within specification, but one or more of your
peak shapes is abnormal in the form of a "shoulder."
C. Split
peaks
One or more of your
peaks is doubled or "split".
D. Flat-top
peaks
The retention times
of all your peaks are within specification, but one or more of your
peak shapes is abnormal in the form of a "mesa" or "flat-topped" peak.
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LC Resources, Inc. all rights reserved