Column preconcentration of trace metals from sea-water with macroporous resins impregnated with lipophilic tetraaza macrocycles

Abstract

Macroporous resins impregnated with lipophilic tetraaza macrocyclic derivatives were used for the uptake and enrichment of trace metals from sea-water prior to their determination by electrothermal atomic absorption spectrometry. The effects of the size of the macrocycle cavity, the support used for impregnation, the pH of the extraction and the parameters of the back-extraction were studied in a column process. The preconcentration of trace metals (Cd, Cu, Mn, Ni, Pb and Zn) from de-ionized water and sea-water was investigated. Satisfactory results were obtained for Cd, Mn, Pb and Zn with an average recovery of 98 ± 8%. Absolute blanks are in the range 1–10 ng and the detection limit varies from 0.7 ng for Cd to 15 ng for Pb. The accuracy of the method was demonstrated by replicate analyses of the National Research Council of Canada marine reference material NASS-2 (open ocean sea-water). The precision is better than 15%(1σ). The selectivity of the resin for Cd, Cu, Mn, Ni, Pb and Zn over Na^I, Ca^II and Mg^II was studied.