Solvent extraction of lead(II) with N-cyclohexyl-N-nitrosohydroxylamine into methyl isobutyl ketone

The distribution equilibrium of the lead-cnha complex in the water-methyl isobutyl ketone (MIBK) system has been studied at 25 degrees . From graphical treatment of the equilibrium data, it was deduced that PbL(2) is the complex extracted. By use of the program LETAGROP-DISTR, values for the distribution and the stability constants of PbL(2) have been calculated: log K(DC) = 1.84 +/- 0.11; log beta(1) = 6.68 +/- 0.09 and log beta(2) = 10.28 +/- 0.09. On the basis of these results and those of previous studies, a method for determination of lead(II), copper(II) and cadmium(II) by atomic-absorption spectrometry, after extraction with cnha and 4-methylpyridine into MIBK, is proposed.