A simple solid-phase extraction method has been described for the separation of Fe(III) and Cu(II) from liquid vegetable oils using N,N′-bis(4-methoxy salicylidene) ethylenediamine impregnated silica gel and the determination of these ions. The experimental parameters that affect the separation/preconcentration of ions were investigated by batch and column methods prior to the determination by flame atomic absorption spectrometry. Fe(III) and Cu(II) ions in 20.0 g portion of oil samples can be quantitatively sorbed and then eluted completely with 5.0 mL of 2.0 mol L−1 HNO3. Limits of detection were calculated as 22.8 and 13.9 μg kg−1 for Fe(III) and Cu(II), respectively. The repetition of the suggested method was checked by finding relative standard deviation for five repeated analyses, which was 1.5% for Fe(III) and 0.1% for Cu(II). Applicability of the method was controlled with spiked and unspiked sunflower, corn, canola, olive, soya and hazelnut oils.
N,N'-bis(4-methoxysalicylidene) ethylenediamine impregnated silica gel is used as solid phase for separation/preconcentration of Cu(II) and Fe(III) from vegetable oils. Determination of the ions were achieved using flame atomic absorption spectrometry (FAAS). Elimination of the hard organic matrix of oils for metal determination is expensive, involves explosion risks and laborious. The suggested procedure overcomes the mentioned disadvantages.