A SOLVENT-EXTRACTION ATOMIC-ABSORPTION TECHNIQUE FOR THE SIMULTANEOUS DETERMINATION OF LOW CONCENTRATIONS OF IRON, NICKEL, CHROMIUM AND MANGANESE IN DRINKING-WATER

A simple and rapid method has been developed for the extraction of Fe, Ni, Cr and Mn in drinking water samples with a new reagent, pentamethylene dithiocarbamate, into methyl isobutyl ketone (MIBK) and their subsequent determination by atomic-absorption spectrometry. The extraction has been carried out at a high aqueous: organic phase ratio to achieve a 35-fold preconcentration factor. Extraction parameters and interference factors are discussed. The precision based on replicate analyses is between 3 and 10% for a concentration range of 2-250-mu-g/l. of the four metals. The detection limits (3-sigma) for Fe, Ni, Cr and Mn are 0.30, 0.36, 0.40 and 0.22-mu-g/l., respectively, corresponding to a metal concentration of 0.50-mu-g/l.