Simultaneous determination of Cd(II), Cu(II) and Pb(II) in surface waters by solid phase extraction and flow injection analysis with spectrophotometric detection

A method for heavy metal monitoring using spectrophotometric detection is p resented. Traces of Cu(ii), Pb(ii) and Cd(ii) at the low mug l(-1) level ca n be determined simultaneously after both selective removal of metal interf erences and preconcentration using 'extraction chromatographic resins'. Lew atit TP807'84, which contains di(2,4,4-trimethylpentyl)phosphinic acid as a ctive component, was used as solid adsorbent. Two minicolumns containing th is resin were used: one at pH 3.2 for the removal of interferences, such as Zn(ii) and Fe(iii), and the other at pH 5.5 for the selective preconcentra tion of the target analytes. Spectrophotometric determination used FIA meth odology with sulfarsazene as chromogenic reagent and partial least-squares multivariate calibration. The method was successfully applied to the analys is of surface waters from the Llobregat river and ground water samples from wells in the Guadiamar basin. Accuracy, expressed in terms of recoveries, was in the range 80-120% and relative standard deviations were below 10%.