ELSEVIER Talanta 44 (1997) 1037- 1053 Talanta Equilibrium and kinetic properties of a fast iminodiacetate based chelating ion exchanger and its incorporation in a FIA-ICP-AES system Payman Hashemi *, Ake Olin Department qf Analytical Chemistry, Uppsala University, P.O. Boy 531, S-751 21 Uppsala. Sweden Received 6 September 1996; received in revised form 22 November 1996: accepted 23 November 1996 Abstract The equilibrium and kinetic properties of an iminodiacetate (IDA) based chelating ion exchanger with a crosslinked agarose, Novarose TM, as support has been investigated. The second and third acidity constants and some complexa- tion constants of the ligand were determined for adsorbents with metal binding capacities of 140, 55 and 18 gmol ml ~, respectively. The adsorbent of medium capacity showed fast adsorption and desorption of Cu(ll), Cd(lI), Ni(ll) and Ca(If) both in the batch and column mode. It was found to be about 50 times faster than Chelex-100 (50- 100 mesh) in accumulation of these metal ions in the batch mode. Studies of the adsorbent in a flow system, using a 5 mm x 6 mm i.d. column, indicated quantitative accumulation of Cu(II), Cd(II), and Ni(II) at volumetric flow rates up to ll0 ml min ~. Linear calibration curves with r > 0.999 and signal enhancement factors up to 1300 were obtained. Preconcentration by a FIA system connected to an ICP-AES instrument will make simultaneous measurement of ultratrace concentrations of a number of metal ions possible within reasonable cycle times due to the high flow rates which can be used with the adsorbent. Trace amounts of cadmium and copper in tap water were determined successfully at 60 ml min 1. However, copper and nickel in tap water are strongly complexed and do not accumulate quantitatively even at low flow rates. Hence a sample pretreatment is needed. Copper was completely adsorbed after UV-treatment of the sample. © 1997 Elsevier Science B.V. Keywords: Flow-injection; Iminodiacetate-agarose metal adsorbent: Inductively coupled plasma atomic emission spectrometry: Tap water analysis 1. Introduction Chelating ion-exchangers have been widely used for preconcentration in trace metal determina- tions by atomic spectrometry [1-5]. A separation from interfering alkali and alkaline earth metals * Corresponding author. can be achieved concurrently. More recently elim- ination of anions, such as chloride and sulphate, has become an important aspect of the ion-ex- change preconcentration-separation procedure as these ions are precursors to some of the disturbing species in determinations by inductively coupled plasma mass spectrometry [6,7]. The most com- monly used ligand in chelating ion-exchangers is 0039-9140,97/$17.00 ¢;, 1997 Elsevier Science B.V. All rights reserved. PII S0039-914(1(96)02189-3