Determination of divalent trace metals in natural waters by preconcentration on N,N,N',N'-tetra(2-aminoethyl)ethylenediamine-silica followed by on-line ion chromatography.

A method for the on-line preconcentration and chromatography of trace metals, e.g., Co, Ni, Cu, Zn, Cd and Pb, on N,N,N',N'-tetra(2-aminoethyl)ethylenediamine-bonded silica is described. The preconcentrated metals were desorbed with 0.13 M tartrate, which allows direct separation on a cation-exchange chromatographic column. The metals separated were detected by postcolumn reaction with 4-(2-pyridylazo)resorcinol and measuring the absorbances at 500 nm. Linear calibration graphs were obtained over the range 1.10(-8)-3.10(-6) M. The synthesis and characteristics of the chelated silica are described. The method was applied to the analysis of river and interstitial sediment waters.