Dionex LC20, Руководство оператора, Страница: 38 / 70

4.5 Peak Ghosting
Ghosting is the appearance of extraneous peaks in a
chromatogram. These may be late-eluting peaks from a previous
injection or result from a contaminated valve or a poor sample
loading technique. These peaks may co-elute with peaks of
interest, resulting in non-reproducible peak heights.
•
Insufficient time between sample injections.
Wait until the previous sample has been completely eluted
before making another injection.
•
Insufficient flush between samples.
Flush the sample loop with at least 10 loop volumes of
deionized water or sample between sample injections.
4.6 Non-Reproducible Peak Height or Retention Time
•
Column overloading.
1. Change to a sample loop with a smaller volume.
2. Dilute the sample.
•
Liquid leaks.
Locate and eliminate the leaks.
Also see “Peak ghosting” in Section 4.5 above.
4.7 Abnormal Retention Time or Selectivity
•
System is not equilibrated following an eluent change.
Allow the system to equilibrate with at least 20 column
volumes of eluent (for example, 30 minutes at 2.0 mL/min
for 4 mm anion separator columns).
•
Flow rate through system is incorrect.
1. Check that the correct flow rate is selected.
LC20 Chromatography Enclosure
4-6
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