Preconcentration of Cr(III), Co(II), Cu(II), Fe(III) and Pb(II) as calmagite chelates on cellulose nitrate membrane filter prior to their flame atomic absorption spectrometric determinations.

A method for the preconcentration and determination of Cr(III), Co(II), Cu(II), Fe(III) and Pb(II) ions by atomic absorption spectrometry has been described. The method was based the collection of metal-calmagite complexes on a soluble cellulose nitrate membrane filter. The detection of the solution was obtained by flame atomic absorption spectrometry (FAAS) after completely dissolving the membrane with 0.5 ml of nitric acid at 80 degrees C. The metal ions were recovered quantitatively at pH 8. Various factors which affect the collection and determination of metal ions such as, type and size of the membrane filter, solvent for dissolution of the species retained on the filter were investigated. The detection limits were varying 0.06 mug l(-1) for Cu to 2.5 mug l(-1) for Cr. An application of the proposed method for analyte ions in mineral and tap water samples was also described with satisfactory results (recoveries >95%, relative standard deviations <10%).