Use of Cu(II) and Fe(III) N-benzoyl-N-phenylhydroxylamine coprecipitants for preconcentration of some trace metal ions in food samples

In this study, new coprecipitation methods were developed using a combination of N-benzoyl-N-phenylhydroxylamine (BPHA) as a chelating reagent and copper(II) and iron(III) as coprecipitate carriers. The determinations of Fe(III), Cr(III) and Cr(VI) with Cu(II)–BPHA coprecipitant and of Cu(II), Pb(II), Cr(III) and Cr(VI) with Fe(III)–BPHA coprecipitant were made by flame atomic absorption spectrometry. The surface morphology of coprecipitants was examined by scanning electron microscopy. The coprecipitation conditions for each method such as the effect of pH, the amounts of carrier element and BPHA, sample volume and matrix effects were examined. The optimum pH for each method was found to be 6. The detection limits of the methods changed in the range of 0.23–3.2 μg L−1 with an enrichment factor of 100. The RSD % was ⩽4.2. The accuracy of the methods was confirmed by analysing the certified reference material. The developed methods were applied for the determination of analytes in food samples.