1
– Introduction
Thermo Scientific
Product Manual for the ERS 500 Suppressor
Page 16 of 84
031956-11
For Research Use Only. Not for Use in Diagnostic Procedures.
1.2.1
Mode of Operation Selection
The Dionex ERS 500 mode of operation depends mainly on the eluent composition, the analysis
sensitivity requirements and the sample matrix. The compatibilities are shown in
Table 1. For example, eluents containing organic solvents that tend to oxidize easily are not
compatible with the AutoSuppression Recycle Mode. The AutoSuppression External Water
Mode should be used instead, or a Dionex CRS suppressor employed in Chemical Suppression
Mode. The MPIC Suppression Mode is specifically designed for applications where ion-pair
reagents and solvents are present in the eluent. The Neutralization Mode can be used with any
eluent composition.
Table 1
Eluent Composition and Suppression Mode Compatibility
Eluent
Composition
Suppression
Recycle
Suppression
External Water
(1)
Chemical
Suppression
(2)
MPIC
Suppression
Aqueous Eluents (excluding
borate)
Yes
Yes
Yes
N/A
Borate Eluents
No
Yes
(3)
Yes
N/A
Eluents containing
Organic Solvents that are
easily oxidized
No
Yes
(Up to 40%)
(3)
Yes
(Up to 100%)
N/A
Eluents containing Organic
Solvents that are not easily
oxidized
Yes
Yes
Yes
Yes
Eluents Containing Ion Pair
Reagents with or without
Solvents
No
No
No
Yes
Simple Aqueous Samples
Yes
Yes
Yes
Yes (assuming Ion
Pairing Reagent)
Complex Samples or
Samples containing Solvents
No
Yes
(3)
Yes
Yes (assuming Ion
Pairing Reagent)
(1)
The Dionex ERS 500 is not recommended for External Water Mode; the Dionex ERS 500e is recommended for External Water Mode
applications.
(2)
The Dionex ERS 500 does not support Chemical Suppression Mode. Use of a Chemically Regenerated Suppressor such as the CRS 500
or equivalent is recommended.
(3)
Only the Dionex ERS 500e is compatible with Borate Eluents and Eluents or Samples containing Organic Solvents that are easily
oxidized.
1.2.2
The AutoSuppression Recycle Mode
The AutoSuppression Recycle Mode uses the suppressed conductivity cell effluent as the source
of water for the regenerant.
This is the preferred method of operation for the Dionex ERS 500
and Dionex AERS 500 Carbonate.
The Dionex ERS 500e is also compatible with this mode.
The advantage of this mode of operation is simplicity and ease of use. This mode reliably
provides AutoSuppression for most suppressed conductivity applications using solvent-free
eluents. For solvents that are not easily oxidized, such as iso-propyl alcohol, the
AutoSuppression recycle mode is preferred. As the eluent passes through the suppressor’s
eluent channel it is converted to a weakly ionized form. After detection, the cell effluent can be
routed back to the regenerant channel to provide the water required for the electrolysis reactions.
The amount of water flowing through the regenerant chambers is therefore limited to the eluent
flow rate. See
