Mercury determination in edible oils – A combination of Reversed-Phase Dispersive Liquid-Liquid Microextraction and CVG-ICP-MS

Abstract A method for Hg determination in edible oils based on reversed-phase dispersive liquid-liquid microextraction and cold vapor generation coupled to inductively coupled plasma mass spectrometry was developed. Operational parameters were 5 g of edible oil, 0.5 mL of n-propanol and 0.5 mL of 6 mol L⁻¹HCl used as dispersant and extractant solvents, respectively, heating (10 min at 80 °C), stirring (60 s), and centrifugation (5 min). No statistical difference (t-test, 95%) was observed for the accuracy assessment using a certified reference material. Moreover, recovery experiments were performed by addition of 0.5, 1.0, and 1.5 µg g⁻¹ of Hg, and recoveries were close to 100%. A low limit of quantification (0.35 ng g⁻¹) and relative standard deviation (7%) were obtained. Finally, the proposed method presented advantages, such as high throughput, easy-to-use instrumentation for sample preparation, high pre-concentration factor, low consumption of reagents, and low waste generation.