The Neutralization Mode - Thermo Scientific Dionex ERS 500 Product Manual

1 – Introduction
regenerant solution from a pressurized bottle delivery system. Dilute boric acid is added to the
water regenerant to enhance detection and improve linearity of weak bases such as ammonia
and amines. This mode is used for MPIC applications requiring an ion pair reagent and organic
solvents in the eluent. The MPIC Suppression Mode reliably provides suppression of typical
eluents for MPIC applications using suppressed conductivity detection. The ion pair reagents,
such as octanesulfonic acid (OSA), are used in concentrations typically ranging from 1.0 to 5.0
mM. Organic solvent concentrations should not exceed 40%. See
operating instructions.
1.2.6

The Neutralization Mode

The Dionex ERS 500 (4 mm) when operated in this mode requires a constant deionized water
flow of 3 to 5 mL/min through the regenerant chambers. The regenerant water can be delivered
from a pressurized bottle or pump. If using a pressurized bottle, it is recommend to use the
Dionex ERS 500e.
The Dionex AERS 500 Carbonate, Dionex ERS 500 (2 mm) and Dionex ERS 500e (2 mm)
suppressors are not designed or validated for the Neutralization Mode. The Dionex ERS
IMPORTANT
500e (4mm) suppressor is recommended and validated for this mode. The Dionex ERS 500
(4 mm) suppressor may also be used for this mode.
1.2.6.1 Neutralization Theory
Figure 4
As shown in
regenerant undergoes electrolysis, forming hydronium ions at the anode and hydroxide ions at
the cathode.
In the Dionex AERS 500, hydronium is transported from the anode towards the cathode and
enters the sample chamber. At the same time, the matrix cations in the sample move towards the
cathode and enter the cathode chamber. The matrix cations combine with the hydroxide ions at
the cathode forming a base, and are removed from the regenerant chamber. The net effect of this
Thermo Scientific
031956-11
AutoNeutralization of Concentrated Acid/Base with the Self-Regenerating
Neutralizer
Dionex AERS 500
Figure 4, when a potential is applied across the two electrodes, the water
Product Manual for the ERS 500 Suppressor
For Research Use Only. Not for Use in Diagnostic Procedures.
Section 3 for complete
Dionex CERS 500
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