IonPacAS9-SC
034656-06
Page 24 of 28
6.2.5 Contaminated Hardware
To eliminate the hardware as the source of the high background conductivity, bypass the columns and the suppressor. Pump
deionized water with a specific resistance of 18.2 megohm-cm through the system. The background conductivity should be less
than 2 µS. If it is not, check the detector/conductivity cell calibration by injecting deionized water directly into it. See the
appropriate manual for details.
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. Prepare fresh eluent. If you are using a gradient pump to proportion the eluent, components
from two or three different eluent reservoirs, the resulting eluent composition may not be accurate enough for the
application. Use one reservoir containing the correct eluent composition to see if this is the problem. This may be a
problem when one of the proportioned eluents is less than 5%.
C. Column contamination can lead to a loss of column capacity because all of the anion exchange sites will no longer be
available for the sample ions. For example, polyvalent anions from the sample or metals may concentrate on the
column. Refer to “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 at least 18.2 megohm-cm.
D. Diluting the eluent will improve peak resolution, but will also increase the analytes’ 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 “Column Care”).
After cleaning the column, reinstall it in the system and let it equilibrate with eluent for about 30 minutes. The column
is equilibrated when consecutive injections of the standard give reproducible retention times. The original column
capacity should be restored by this treatment, since the contaminants should be eluted from the column. If you need
assistance in solving resolution problems, contact the nearest DIONEX Worldwide Office (see, DIONEX Worldwide
Offices)
6.2.6 A Contaminated Anion Self-Regenerating Suppressor, ASRS-ULTRA
This section describes routine cleanup procedures for the Anion Self-Regenerating Suppressors (ASRS-ULTRA) in the case of
contamination. Consult the Troubleshooting Guide (see Section 4, “Troubleshooting Guide”) to first determine that the system
is operating properly. If the ASRS-ULTRA is determined to be the source of higher than normal back pressure, higher than
anticipated conductivity, decreased suppression capacity or decreased sensitivity, cleaning the membrane may restore the
performance of the system. Use the following procedures to clean the membrane.
Metal Contaminants or Precipitates
NOTE
The suppressor voltage is a good indicator of the resistance across the suppressor. Higher resistance may indicate
contamination of the suppressor. For more information regarding monitoring the voltage, see Document No.
031814-02, “Removal of Iron Contamination from Electrolytic Suppressors.”
A. Turn off the SRS Control unit.
B. Disconnect the analytical (and guard) column(s) from the injection valve and the ASRS-ULTRA. Refer to the specific
analytical column Product Manual for column cleanup procedures.
C. If you are running in the
AutoSuppression External Water Mode
, turn off the external water and disconnect the
external water line from the ASRS-ULTRA
REGEN IN
port.
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