A planar microelectrodialytic NaOH generator for eluite conversion after suppressed conductometric detection in ion chromatography Original Research Article

A microelectrodialytic NaOH generator (MENG), incorporated after the conductivity detector in a suppressed anion chromatography system based on hydroxide eluents, converts the suppressed eluites from the acid form to a sodium salt (NaOH + HX → NaX + H2O). Against the conductive background of the NaOH generated by the MENG, the eluites appear as negative peaks (OH− replaced by X−). In a conventional conductometric, suppressed anion chromatography system very weak acids produce a very poor response, if at all, because HX is poorly ionized. The present method enables the sensitive detection of weak and very weak acids and also enables analyte identification if conventional detection is simultaneously used. A previous paper described MENG devices of tubular construction. The present paper describes an improved MENG device of planar geometry; relevant performance data pertaining to induced dispersion, background noise and the Faradaic efficiency of the device are presented. New considerations on the merits of the two-dimensional detection approach are outlined.