Multivariate optimization of ultrasound-assisted extraction using Doehlert matrix for simultaneous determination of Fe and Ni in vegetable oils by high-resolution continuum source graphite furnace atomic absorption spectrometry

• Published in: Food chemistry 2019-02, Vol.273, p.130-135
• Main Authors: Almeida, Jorge S., Santos, Gabriel L., Brandão, Geovani C., Korn, Maria G.A., Teixeira, Leonardo S.G.
• Format: Article
• Language: English
• Subjects: HR-CS GF AAS; Multivariate optimization; Simultaneous determination; Ultrasound-assisted extraction; Vegetable oils
• ISSN: 0308-8146; 1873-7072
• DOI: 10.1016/j.foodchem.2018.01.112

•A method for simultaneous determination of Fe and Ni by HR-CS GF AAS is proposed.•Sample pretreatment was performed by ultrasound-assisted extraction.•The optimization of the procedure was performed by applying Doehlert matrix.•The method was applied in the analysis of vegetable oil samples. A method for simultaneous determination of Fe (232.036 nm) and Ni (232.195 nm) in vegetable oil samples by high-resolution continuum source graphite furnace atomic absorption spectrometry (HR-CS GF AAS) after an acid extraction of the analytes is proposed. In the extraction step, hydrochloric, nitric and acetic acid solutions were tested. The optimization of the procedure was performed by applying Doehlert matrix, and multiple response was used for simultaneous evaluation of the performance of the extraction. The optimum conditions were: extraction time of 17 min, extraction temperature of 39 °C and sonication amplitude of 42%, employing 0.5 mol L−1 HCl as the extracting solvent. The limits of quantification were 60 and 160 ng g−1 for Fe and Ni, respectively. The method was applied to the analysis of vegetable oil samples and the results were compared with a method employing inductively coupled plasma optical emission spectrometry (ICP OES).