| In this study, sodium hydroxide-induced homogenous liquid-liquid extraction was combined with effervescent
assisted-dispersive liquid-liquid microextraction and used for the extraction of phytosterols (lupeol, β-sitosterol,
stigmasterol, campesterol, and brassicasterol) from cream samples. Two types of deep eutectic solvents (watermiscible
and water-immiscible solvents) were prepared and used in the extraction procedure. In this approach,
firstly, the sample was dissolved in a mixture of n-hexane and tetrabutylammonium bromide: ethylene glycol
deep eutectic solvent (as extraction/disperser solvent) and a homogenous solution was obtained. After that, a few
microliters of sodium hydroxide solution (as fatty acid saponification and phase separation agent) was quickly
injected into the mixture. By doing so, a three-phase system was formed. Then, the supernatant phase (tetrabutylammonium
bromide: ethylene glycol deep eutectic solvent) was removed and mixed with tetrabutylammonium
bromide: dichloroacetic acid: octanoic acid deep eutectic solvent. The obtained solution was applied
in the microextraction step. To obtain effective, reliable, robust, accurate, and precise analytical results, the
effective parameters for the presented method were investigated and optimized in detail. Detection limits,
extraction recoveries, and enrichment factors were in the ranges of 0.06–0.26 μg kg–1, 86–93 %, and 215–232,
respectively. Intra- and inter-day repeatabilities were investigated at a concentration of 1.5 μg kg–1 (each analyte)
and they were in the ranges of 5.3 7.5 and 7.2–8.8 %, respectively. Finally, the presented method was
easily used in determination of the phytosterols in cow milk cream samples. |