Elution was performed with a 2 mM solution of NaOH during 25 min, followed by regeneration at 5 min with 100 mM NaOH, and equilibration for 15 min with 2 mM NaOH (Sodium hydroxide solution for IC, Sigma-Aldrich, Steinheim, Germany).
Elution was performed with a2 mM solution of NaOH during 25 min, followed by regenerationat 5 min with 100 mM NaOH, and equilibrationfor 15 min with 2 mM NaOH (Sodium hydroxidesolution for IC, Sigma-Aldrich, Steinheim, Germany).