The Dionex Anion Electrolytically Regenerated Suppressor for Carbonate Eluents (Dionex AERS 500 Carbonate) uses water as the regenerant and can provide continuous suppression. The following table lists the eluent concentrations and flow rates of commonly used mobile phases used in anion separations and the optimum / recommended current level to suppress the eluent. The operation of the Dionex AERS 500 Carbonate requires a constant flow of water over the electrodes in a direction that is countercurrent to the flow of the eluent.

In the AutoSuppression Recycle Mode, the eluent leaving the conductivity cell is recycled through the regenerant chambers as the water supply. This eliminates the need for an external regenerant water supply and delivery system. When the Dionex AERS 500 Carbonate is operating in this mode, the amount of water flowing through the regenerant chambers is limited to the eluent flow rate. The AutoSuppression Recycle Mode cannot be used with eluents containing any organic solvents.

The AutoSuppression External Water Mode requires an external source of deionized water for the regenerant chambers. When the Dionex AERS 500 Carbonate is operating in this mode, the amount of water flowing through the regenerant chambers is independent of the eluent flow rate. Because of this, higher regenerant flow rates are achievable. See the following table.

The AutoSuppression External Water Mode is the mode used if organic solvents (up to 40%) are present in the eluent. It eliminates the potential for buildup of contaminating ions resulting from the oxidation of solvents.

Optimum Current Settings for the Dionex AERS 500 Carbonate in the AutoSuppression Recycle and External Water Modes

Column

Eluent

Eluent Flow Rate (mL/min)

Optimum Current (mA)

(2 mm)

(4 mm)

(2 mm)

(4 mm)

AS4A-SC

1.8 mM CO32- / 1.7 mM HCO3-

0.5

2.0

9

34

AS9-HC

9.0 mM CO32-

0.25

1.0

15

58

AS12A

2.7 mM CO32- / 0.3 mM HCO3-

0.38

1.5

7

28

AS14

3.5 mM CO32- / 1.0 mM HCO3-

0.3

1.2

8

31

AS14A

8.0 mM CO32- / 1.0 mM HCO3-

0.51)

1.0

28

55

AS22

4.5 mM CO32- / 1.4 mM HCO3-

0.3

1.2

11

41

AS22-Fast

4.5 mM CO32- / 1.4 mM HCO3-

0.5

2.0

17

67

AS23

4.5 mM CO32- / 0.8 mM HCO3-

0.25

1.0

8

32

The Dionex AERS 500 cannot be used with legacy systems that only provide discrete (50, 100, 300 and 500 mA) current settings.

External Water Flow Rates for Dionex AERS 500 Carbonate (4 and 2 mm)2)

Minimum External Water Flow Rate

Recommended External Water Flow Rate

Maximum External Water Flow Rate

Equivalent to the eluent flow rate

2x the eluent flow rate

2 mL/min (2 mm suppressors)
5 mL/min (4 mm suppressors)