DETERMINATION OF ANIONS AND CATIONS IN CONCENTRATED BASES AND ACIDS BY ION CHROMATOGRAPHY - ELECTROLYTIC SAMPLE PRETREATMENT

The development of a high-capacity electrochemical membrane suppressor has resulted in new ion chromatographic methods for the determination of trace ions in concentrated acids and bases. Unlike previous membra ne suppressors, the new one does not require chemical regeneration, th us eliminating regenerant leakage across the membranes. The new suppre ssor electrolyses water to create the acid or base required for neutra lization and thus permits contamination-free acid-base neutralizations of concentrated reagents. This makes the new suppressor ideal for sam ple pretreatment of acids or bases prior to analysis by ion chromatogr aphy. This technique has been applied to trace anion determination in concentrated bases (e.g. 50% NaOH and concentrated NH4OH) and trace ca tion determination in concentrated acids (e.g. 48% H2SO4, 43% H3PO4 an d 33% methane sulfonic acid). The detection limits for most ions are 1 to 10 ng/ml.