SIMULTANEOUS DETERMINATION OF CO(II), CR(VI), NI(II) AND PB(II) IN WATER BY SOLVENT-EXTRACTION AND HIGH-FIELD H-1-NMR SPECTROMETRY

A novel analytical approach is described that combines the preconcentr ation power of solvent extraction with the resolution and sensitivity of a 500 MHz H-1 NMR spectroscopic detection method for the quantitati ve determination of metals. Co(II), Cr(VI), Ni(II) and Pb(II) in water are extracted into chloroform as dithiocarbamate complexes. By decoup ling the protons and employing a solvent-induced shift method, the H-1 NMR spectrum containing the dithiocarbamate complexes of Co(II), Cr(V I), Ni(II) and Pb(II) is fully resolved at CDCl3/C6D6 below 40%/60%. T he detection limits for Co(II), Cr(VI), NI(II) and Pb(II) are estimate d to be 0.12, 0.073, 0.11 and 0.27 mu g/mL, respectively, in the sampl e solution.