Spectrometric determination of iron and copper in vegetable oils after separation with Schiff base impregnated silica gel column: A simple approach for eliminating the high organic matrix

Summary 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 HNO 3 . 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.