A simple and fast Fe3O4 magnetic nanoparticles-based dispersion solid phase extraction of Sudan dyes from food and water samples coupled with high-performance liquid chromatography

Abstract

In recent years, nanoparticles, particularly magnetic nanoparticles (MNPs), have been emerging as a new type of important functional solid phase extraction (SPE) material. However, there has been no report on the direct application of Fe₃O₄ MNPs for the extraction of trace Sudan dyes as a SPE material in food and environmental analysis. In this work, Fe₃O₄ MNPs from a one-pot chemical coprecipitation route were prepared under ultrasound irradiation. The as-obtained Fe₃O₄ MNPs showed good adsorbability to the four Sudan dyes and were successfully applied as a SPE material coupled with high-performance liquid chromatography (HPLC) for the simultaneous isolation and determination of four Sudan dyes from foodstuff and water samples. Compared to the traditional SPE adsorbents, such as neutral alumina and C₁₈, the Fe₃O₄ MNPs adsorbents provided simple, fast and easy operation with an effective purification effect. The results on the water matrix suggest that such purification can be considered a practicable solution for sample preparation in the routine analysis of Sudan dyes in environmental samples with good anti-interference ability to natural organic matter, and can detect Sudan dyes down to 0.02 μg L⁻¹ when sample volumes of 750 mL and 500 mg Fe₃O₄ MNPs adsorbents were adopted. Also, the proposed method could be potentially applied to the rapid isolation and determination of Sudan dyes in complicated matrices, such as food samples, and can detect Sudan dyes down to 10 μg kg⁻¹ when 1 g foodstuff and 500 mg Fe₃O₄ MNPs adsorbents were used. The as-obtained Fe₃O₄ MNPs showed operational stability and retained excellent adsorption and magnetic properties, even after an eight-cycle run for the adsorption and desorption of Sudan dyes.