Extraction of fat-soluble vitamins by solidification of a sedimentary ionic liquid droplet liquid phase microextraction

Abstract

In this study, ultrasound-assisted emulsification microextraction with solidification of a sedimentary drop of ionic liquid (USAEME-SSIL) was used to extract fat-soluble vitamins from aqueous samples. For the first time, an amphiphilic ionic liquid, 2-thiahexadecyl-1-methylimidazolium bis[(trifluoromethyl)sulfonyl] imide ([mimSC16][NTf2]), was employed as a solvent in USAEME-SSIL method. The amounts of extracted vitamins were determined by high performance liquid chromatography (HPLC) and Ultraviolet –Visible detection. Effect of several parameters on USAEME-SSIL extraction efficiency including type and amount of ionic liquid, pH, temperature, time of sonication and centrifuging were optimized. The optimum conditions were 20 mg [mimSC16][NTf2], solution temperature of 50 °C, 10.00 mL of sample solution with pH = 6 containing 15 % (w/v) NaCl, sonication time of 4 min and centrifugation at 4000 rpm for 7 min. The calibration curves were plotted using the internal standard method. The findings indicated that all curves displayed linearity within the range of 0.50 to 4.00 mg L -1 (R2 > 0.9982). This technique demonstrated excellent consistency (%RSD ≤ 1.21), low limits of detection (LOD < 76.50 µg/L), high accuracy (recoveries > 92.40 %), and significant enrichment factors (EF > 13.50). The application of this method proved successful in analyzing fat-soluble vitamins in pharmaceutical samples. © 2024 Elsevier B.V.