5
– Troubleshooting Guide
Thermo Scientific
Product Manual for CarboPac PA200 Columns
Page 30 of 37
065734-01
For Research Use Only. Not for use in diagnostic procedures.
5.3.2
Shortened Retention Times
Even with adequate system and column efficiency, resolution of peaks will be compromised
if analytes elute too fast.
A.
Check the flow rate. See if the eluent flow rate is equivalent to the flow rate specified by
the analytical protocol. Measure the eluent flow rate after the column using an analytical
balance.
B.
Check to see if the eluent compositions and concentrations are correct. An eluent that is
too concentrated will cause the peaks to elute faster.
C.
Column contamination can lead to a loss of column capacity. Highly retained
contaminant ions will occupy a portion of the anion exchange sites limiting the number
of sites available for retention of analyte ions. Refer to "
Appendix A, Dionex CarboPac
PA200 Column Care
”, for recommended column cleanup procedures.
Possible sources of column contamination are impurities in chemicals and in the
deionized water used for eluents or components of the sample matrix. Be especially
careful to make sure that the recommended chemicals are used. The deionized water
should have a specific resistance of 18.2 megohm-cm.
D.
Diluting the eluent will improve peak resolution, but will also increase the retention
times. If a 10% dilution of the eluent is not sufficient to obtain the desired peak
resolution, or if the resulting increase in retention times is unacceptable, clean the
column (see
Appendix A, Dionex CarboPac PA200 Column Care
).
After cleaning the column, follow the system re-start procedure (see Section 3.4
System Re-start) BEFORE reinstall the column in the system and let it equilibrate with
eluent for about 30 minutes directing the column effluent to waste. Then connect the
column to the electrochemical detector cell. The column is equilibrated when
consecutive injections of the standard result in reproducible retention times. The
original column capacity should be restored by this treatment, since the contaminants
should have been eluted from the column.
For assistance, contact Technical Support for Dionex Products. In the U.S., call 1-800-
346-6390. Outside the U.S., call the nearest Thermo Fisher Scientific office.
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