Scf. Auyeung et al., SIMULTANEOUS DETERMINATION OF CO(II), CR(VI), NI(II) AND PB(II) IN WATER BY SOLVENT-EXTRACTION AND HIGH-FIELD H-1-NMR SPECTROMETRY, Fresenius' journal of analytical chemistry, 361(2), 1998, pp. 210-213
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.