FLOW-INJECTION COLUMN PRECONCENTRATION DIRECTLY COUPLED WITH ELECTROTHERMAL ATOMIZATION ATOMIC-ABSORPTION SPECTROMETRY FOR THE DETERMINATION OF ALUMINUM - COMPARISON OF COLUMN PACKING MATERIALS

A method has been developed for the determination of endogenous levels of aluminium (> 1 mu g l(-1)) in water samples using an automated on- line preconcentration system with flow injection coupled directly to a n electrothermal atomic absorption spectrometer. Two preconcentration materials, 8-quinolinol immobilized on controlled-pore glass (8-Q-CPG) and Amberlite XAD-2, poly(styrene/divinyl benzene) copolymer (XAD-2) were investigated and compared. Both systems were found to be suitable for preconcentration. However, the sampling flow-rate for the 8-Q-CPG system was found to be much lower than that of the XAD-2 system, rela tive to the same magnitude of preconcentration. The chelating kinetics of the 8-Q-CPG system were less favourable than the adsorption kineti cs of the XAD-2 system. The detection limits (3SD) varied from 15 to 4 0 ng l(-1), depending on the preconcentration time, with RSDs of the o rder of 4% for a 1 mu g l(-1) concentration of aluminium. The optimum concentration range for the application of the method developed was 50 ng l(-1) to 3 mu g l(-1). Recoveries for drinking water were in the r ange 100-115% for the 8-Q-CPG system and 90-100% for the XAD-2 system. The method developed was applied with varying results to the analysis of potable, fresh, river and sea water samples.