ETAAS DETERMINATION OF ALUMINUM AND COPPER IN DIALYSIS CONCENTRATES AFTER MICROCOLUMN CHELATING ION-EXCHANGE PRECONCENTRATION

A procedure was developed for the preconcentration and determination o f aluminium and copper in dialysis concentrates at the ng cm(-3) level . The preconcentration was achieved on microcolumns filled with Chelex -100 resin adjusted to a pH of 4.0. Five repetitive cycles of the samp le through the column ensured a sufficient contact time for quantitati ve retention of aluminium and copper ions. The retained ions were elut ed with HNO3 (0.5 mol dm(-3)). Aluminium and copper were determined in the eluate by Zeeman ETAAS using the standard addition technique. The procedure was performed under clean room conditions (class 10,000), T he reliability of the results was evaluated by recovery tests, using d ialysis concentrates spiked with aluminium and copper. The recoveries obtained ranged from 86 to 106% for aluminium and from 92 to 97% for c opper. Using the recommended procedure, the LOD of aluminium and coppe r in dialysis concentrates (preconcentration factor 2) was found to be 0.5 ng cm(-3) and 0.2 ng cm(-3), respectively.