Development of emulsion breaking method for the extraction of some anions from edible oil samples and determination by ion chromatography

In this study, a method based on extraction-induced emulsion breaking (EIEB) was developed and validated for the determination of inorganic anions in edible vegetable oils. The developed extraction procedure was applied to vegetable oil samples, followed by ion chromatographic analysis of F-, Cl-, NO2-, Br-, NO3-, PO43- and SO42- anions. During method development, key parameters such as acid and surfactant type and concentration, emulsion breaking time and temperature, and sample amount were optimized. Validation was performed using representative matrices, including seed oil, essential oil, fruit oil, and high-viscosity oil. The EIEB procedure involved emulsifying 2 g of sample with 2 mL of an aqueous phase containing 0.1% (v/v) formic acid and 4% (w/v) Triton X-100, followed by phase separation at 85°C. The %RSD values were found to range between 0.937–6.382% in coconut oil, 0.184–6.849% in peppermint oil, 0.84–3.571% in sunflower oil, and 0.992–5.629% in olive oil. The LOD values for F-, Cl-, NO2-, Br-, NO3-, PO43- and SO42- were determined as follows (in µgkg-): 4.7 (coconut oil), 42.2 (sunflower oil), 2.3 (peppermint oil), 10.1 (sunflower oil), 29.3 (sunflower oil), 24.9 (coconut oil), and 44.4 (coconut oil), respectively.