NON-SUPPRESSED ION CHROMATOGRAPHY OF INORGANIC ANIONS, MAGNESIUM AND CALCIUM-IONS USING A PYROMELLITATE ELUENT AND ITS APPLICATION IN EVALUATING ENVIRONMENTAL WATER-QUALITY

A simple, sensitive and convenient ion chromatographic (IC) method wit h UV photometric detection using pyromellitate (1,2,4,5-benzenetetraca rboxylate)-methanol-water as the eluent on a silica-based anion-exchan ge column was established for the simultaneous determination of common inorganic anions including HCO3-, Mg2+ and Ca2+ in environmental wate rs. The anions were detected indirectly, whilst Mg2+ and Ca2+ were det ected directly because complexes having strong UV absorption were form ed between pyromellitate and these cations. The proposed method was su ccessfully applied to the simultaneous determination of the common ani ons, Mg2+ and Ca2+ in various river water samples.