Dionex Corporation Home

ERD 500 Electrolytically Regenerated Desalter

On-line Device for Users of HPAE-PAD to Collect and Further Analyze Carbohydrate Samples

High-pH HPAE-PAD has become the method of choice for oligosaccharide purification because it permits very high resolution of neutral and charged oligosaccharide isomers. Subsequent characterization of purified oligosaccharides often requires removal of eluent salts. Manual desalting methods are available; the Thermo Scientific Dionex ERD 500 Electrolytcally Regenerated Desalter provides an easier, automated method.

  • Reduces the pH of the effluent from pH ~13 to between pH 2–6
  • Supports lyophilization of collected fractions without dialysis
  • Provides minimal dispersion of the sample exiting the detector cell
  • Low dispersion for accurate fraction collection
  • >99% sodium ions removed from eluents that contain up to 0.35 M sodium ions

The Dionex ERD 500 desalter exchanges sodium ions in the eluent for hydronium ions. This process converts sodium hydroxide and sodium acetate eluents to water and acetic acid, lowering sample pH after samples leave the detector cell. Because acetic acid is volatile, fractions can then be lyophilized without dialysis, leaving the purified carbohydrate sample ready for further manipulation.

The Dionex ERD 500 desalter reliably desalts up to 0.35 M Na at an eluent flow of 1.0 mL/min. Oligosaccharides eluting in up to 0.35 M Na, collected after on-line desalting and evaporated in a centrifugal vacuum evaporator, exhibit residual [Na+] below 200 μM after resuspension to original volume in deionized water. This represents a desalting efficiency of >99.9%.