Chromatography Forum

I've been trying to separate aceteate and lactate by IEC using a Dionex AS11 column and a dilute (< 1 mM) NaOH eluant with conductivity detection. The peaks are poorly resolved and overlapping at higher concentrations. The column literature suggests that this separation should be possible.

Does anyone have any suggestions?

Is yours an AS11 or an AS11-HC? The AS11-HC is much better for this application. Have you looked at the product datasheet?
http://www1.dionex.com/en-us/webdocs/41 ... HC_V15.pdf
It compares the two columns in Figure 1. Also, try raising the temperature to 30 °C.

You can also consider the just-introduced Acclaim Mixed-Mode WAX. The user's guide is at:
http://www1.dionex.com/en-us/webdocs/48 ... olumns.pdf