DETERMINATION OF INORGANIC AND ORGANIC-ANIONS IN ONE RUN BY ION CHROMATOGRAPHY WITH COLUMN-SWITCHING

A method for the simultaneous determination of low-molecular-mass orga nic and inorganic anions in aqueous solutions was developed using isoc ratic ion chromatography (IC) with suppressed conductimetric detection and column switching. Owing to the large differences in distribution coefficients between sulphate, nitrate and phosphate and the other spe cies, these ions are separated in the first stage on a medium-capacity anion exchanger, whereas the other anions are led through a second co lumn packed with a high-capacity anion-exchange resin via a column-swi tching valve. After optimization of the switching procedure a spiked d rinking water sample was analysed. Fluoride, acetate, butyrate, format e, nitrate, nitrite and phosphate could be determined in addition to t he main anions (chloride and sulphate). The time for a complete analys is is less than 20 min and the method can easily be automated. The pre cision and detection limit are as usual in IC with background suppress ion.