Switchable-hydrophilicity solvent liquid-liquid microextraction prior to magnetic nanoparticle-based dispersive...

A combination of switchable-hydrophilicity liquid-liquid microextraction prior to magnetic nanoparticle-based dispersive solid-phase microextraction is proposed for the determination of erythrosine using UV/Vis spectrophotometry at 520 nm. Under optimum conditions (i.e., 1.0 mL octylamine as the extraction solvent, 1.5 mL of 10.0 M sodium hydroxide as the phase separation trigger, pH 4.0, 750 µL of acetone as the eluent, 10.0 mg of Fe₃O₄@XAD-16 as the adsorbent, and 15.0 mL of the sample solution), the method showed a superior analytical performance with limits of detection less than 25.9 ng mL^-1, limits of quantitation less than 86.3 ng mL^-1 and linear dynamic ranges ranging between 86.3 and 1000 ng mL^-1. Percentage relative standard deviations were less than 4.1 and 7.2% for intra-day and inter-day, respectively. The method was successfully applied for the extraction and determination of erythrosine in food samples and other consumer products with recoveries in the range of 94.6-103.9% and within extraction time of 7.8 min per sample.