Properties of a high capacity iminodiacetate-agarose adsorbent and its application in a flow system with on-line buffering of acidified samples for accumulation of metal ions in natural waters

Adsorption properties of a fast iminodiacetate-agarose adsorbent, IDA-Novarose, with a capacity of 120-140 mu mol/ml were studied for preconcentration of eight transition elements. A FIA-ICP-PLES system was used in the study. It was shown that 0.3 ml of the adsorbent, packed in a column, can quantitatively accumulate Cr3+, Mn2+, Fe3+, Co2+, Ni2+, Cu2+, Zn2+ and Cd2+ from standard solutions in the pH range between 4 and 8 at high loading flow rates (10-80 ml/min). The rate of adsorption was studied in batch experiments and found to be fast and equal for the divalent metal ions but relatively slow for accumulation of Cr3+ and Fe3+. On-line buffering of acidified samples improved the accumulation of metal ions from synthetic samples spiked with humic acid. Quantitative uptakes were observed for most of the studied metals. The accumulation of Cr3+ was found to be quite sensitive to the ionic strength and some loss of inert complexes of Fe3+ was also observed. The method was applied to the analysis of certified riverine water (SLRS-3), a tap water and a lake water. With few exceptions the results obtained by ICP-AES after preconcentration agreed well with the certified concentrations and results found by ICP-MS. (C) 1999 Elsevier Science B.V. All rights reserved.