SIMULTANEOUS ION-CHROMATOGRAPHY OF ALKALI, ALKALINE-EARTH AND HEAVY-METAL IONS WITH CONDUCTIVITY AND INDIRECT UV DETECTION - COMPARISON OF ELUENTS CONTAINING ORGANIC COMPLEXING ACIDS AND COPPER-SULFATE

The simultaneous ion-chromatography of mono-and divalent metal ions on the weak cation-exchange column Nucleosil-PBDMA (polymer coated silica with polybutandiene-maleic acid) with conductivity and indirect UV-detection is presented. The influences of eluents containing organic complexing acids (α-hydroxy-isobutyric, tartaric, citric, oxalic, pyridine-2,6-dicarbonic acid and EDTA etc.) as well as UV-absorbing, displacing counterions [Cu(II), Ce(III) etc.] on the retention times of metal ions was investigated in detail. With the combination of citric acid-PDCA as eluent all alkali and alkaline earth ions could be completely separated within 12 min. Alkali, alkaline earth and heavy metal ions [Cu/Zn/Co/Fe(II)] were separated by the combination of tartaric and oxalic acid as eluent in a single run. Trace amounts of Na, K and Ca were successfully separated from the Mg-matrix by an EDTA-PDCA eluent. For the IC with indirect UV-detection the eluent consisting of CuSO4 or CuCl2 was used to separate Na, K, Mg and Ca with baseline resolution within 10 min. The detection limits of metal ions with conductivity detection were found beween 0.5 μg/l for Li and 8 μg/l for Cs. They were 10 times more sensitive than those with indirect UV-detection. This IC-method was applied to determine alkali, alkaline earth and Mn ions in the water, food, ore-cinder and sole-brine samples with satisfactory results. © 1990 Springer-Verlag.