A new method has been developed for the extraction and determination of zinc and nickel in liquid edible oils by using the complexation of these metals with [N,N 0 -bis(salicylidene)-2,2 0 -dimethyl-1,3propanediaminato]. Zn(II) and Ni(II) complexes with a tetradentate Schiff base have been investigated spectrophotometrically. Experimental extraction conditions for these metals from liquid oil standards were optimized using central composite design. Optimum conditions for Zn(II) and Ni(II) extractions from oil have been found close to each other. The ratio of the volume of used Schiff base solution to the amount of oil (V LDM /m oil ; mL/g), the stirring time and the temperature were round about 1.00 mL/g, 55 min, 328C, respectively, for simultaneous determination of both metals in same sample. The recovery percentages at the optimum experimental conditions were found 98.9 AE 2.8 and 101.8 AE 4.7 for Zn(II) and Ni(II), respectively. The proposed method was applied on the raw and spiked samples such as olive oil, sunflower oil, corn oil, canola oil and obtained recovery values were between 93.7-107.2 and 93.1-101.1% for Zn(II) and Ni(II), respectively.Practical applications: There is interest in the determination of metals in liquid edible oils because of their catalytic effect on the oxidation reaction of oils. A new method for the determination of Zn(II) and Ni(II) in liquid edible oils which does not require any digestion or decomposition was developed. This study offeres a cheap, rapid, accurate, sensitive, risk-free, and practical metal determination method after the extraction.Abbreviations: AAS, atomic absorption spectrometry; ICP-AES, inductively coupled plasma atomic emission spectrometry; FAAS, flame atomic absorption spectrometry; LDM, [N,N 0 -bis(salicylidene)-2,2 0dimethyl-1,3-propanediaminato]; LOD, limit of detection 1320Eur.

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A new method for the determination of copper(II) and iron(III) in liquid edible oils which does not require a digestion step was developed. The suggested method involves extraction of metals with [N,N 0 -bis(salicylidene)-2,2 0 -dimethyl-1,3-propanediaminato] (LDM) followed by flame atomic absorption spectrometry measurement. As a first step, metal complexes of copper(II) and iron(III) ions with LDM were investigated spectrophotometrically. After the analytical properties and experimental conditions of the complexation had been determined, these findings were used to determine the extraction period as a second step. Experimental conditions were optimized using a central composite design. Optimum conditions for Cu(II) and Fe(III) extractions from oil were found: the ratios of the volume of Schiff base solution used to the mass of oil (V LDM /m oil ; mL g -1 ) were 0.76 and 1.19 mL g -1 , the stirring times were 73 and 67 min, and the temperatures were 31 and 28°C, respectively. The developed extraction and determination method was tested on certified reference materials; the recovery percentages were found to be 99.4 ± 2.8 and 100.2 ± 5.6 for Cu(II) and Fe(III), respectively. The suggested method was performed on real samples such as olive oil, sunflower oil, corn oil, canola oil and recovery values between 97.2-102.1 for Cu(II) and 94.5-98.6 for Fe(III) were determined. It was concluded that the developed method has some advantages over the common traditional method including rapidity, sensitivity, accuracy, reduced risk and cost.

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Fractionation of elements in food is essential for understanding and prediction of its bioavailability, effects, and toxicity. In the present study, an analytical fractionation scheme for milk samples was developed for the common elements, such as Fe, Cu, Zn, Mn, Mg, Ca, Cr, Ni, Mo, Al, Pb, Sn, V, Ba, Co, and Cd. For this purpose, applying a sequential separation procedure, the protein, lipid, and serum fractions were obtained separately. The recovery percentages were in the range of 96.3-104.0 for the separation of fractions in the synthetic milk. The results achieved in the paper were compared with reported literature data. Additionally, the fractionation pattern for each metal studied was different relating to the origin of milk. Although there were some exceptions, it was seen that Fe, Cu, and Al preferred to be in protein fraction; however, Zn, Mn, Mg, Ca, Cr, Ni, and Mo preferred to be in serum fraction.