Extractive and spectrophotometric determination of zinc(II), tellurium(IV) and iron(III) with 4-p-nitrobenzoyl-2,4-dihydro-5-methyl-1-phenyl-pyrazol-3-one

A new method for the extraction and spectrophotometric determination of Zn(II), Te(IV) and Fe(III) with 4-p-nitrobenzoyl-2,4-dihydro-5-methyl 1-phenyl-pyrazole-3-one (NBDMPP) at microgram level is described after preconcentration using tetradecyldimethylbenzylammonium (TDBA) iodide-naphthalene as an adsorbent. TLC resolution of complex mixtures using the binary solvent, acetonitrile-1,4 dioxane in the ratio 70:30 provide effective separation of the complexes, especially when surfactant TDBA is used. The molar absorptivities for ail these complexes are found to be 1.09 x 10(4), 1.68 x 10(4), 9.46 x 10(3) l mol(-1) cm(-1) respectively while Sandell's sensitivities are 0.0060, 0.0049, 0.0059 mu(-2) cm(-2) respectively. The developed method has been used for the determination of these metals in alloys.