INSTRUMENTATION & METHODS ...
The anion method is a gradient elution beginning with an initial 8 minute equilibration period, followed by an isocratic 12 minute 5 mM sodium hydroxide elution, followed by a linear gradient from 5 mM to 35 mM sodium hydroxide from 12 minutes until 56 minutes at a flow rate of 0.25 ml/min. The cation method is an isocratic elution using 20 mM methanesulfonic acid (MSA) at a flow rate of 0.36 ml/min for 60 minutes.