DETERMINATION OF TRACE AMOUNTS OF SB, PB, TL IN WATER SAMPLES BY INDUCTIVELY-COUPLED PLASMA-ATOMIC EMISSION-SPECTROMETRY AFTER A DIANTIPYRYLMETHANE-IODIDE 3RD-PHASE PRECONCENTRATION

A preconcentration method based on third phase extraction has been dev eloped and combined with inductively coupled plasma atomic emission sp ectrometry (ICP-AES) for determination of Sb, Pb, Tl at trace levels i n water samples. The reagents diantipyrylmethane and potassium iodide were applied for complexing Sb, Pb, Tl and producing a third phase ext raction system. This third phase system produces relatively large enri chment factors and complete isolation of trace elements from high salt -containing matrices which influence strongly the plasma condition. Ex perimental parameters of the extraction, such as concentrations of com plexing reagents, pH and extraction time have been optimized. Under th e selected conditions, this third phase ICP-AES combination procedure gave multielemental detection limits for Sb, Pb, Tl which are superior by an order of magnitude or more to those obtained by ICP-AES alone w ithout preconcentration. Precision of the technique is better than 10% at the 10 mu g/l level. The accuracy of this approach is demonstrated by its application to tapwater, artificial seawater and reference sea water samples.