Determination of Carotenoids in Egg Yolk by High Performance Liquid Chromatography with Vortex-Assisted Hollow Fiber Liquid-Phase Microextraction using Mixed Extraction Solvent

A vortex-assisted hollow fiber liquid-phase microextraction method using a mixed solvent as the extraction solvent followed by high performance liquid chromatography diode-array detection was developed for the extraction and determination of two carotenoids including lutein and beta-carotene from egg yolk. The method is based on the microextraction of carotenoids from sample solution into extracting agent (20 mu L), which is located in the lumen of hollow fiber followed by vortex-mixing. The mixed solvent (1-octanol+1-undecanol, 6:4, v:v) was employed as extracting agent for it has suitable viscosity and compatible with carotenoids via hollow fiber. Vortex-mixing was utilized to provide effective and mild mixing of sample solution and increase the contact between analytes and boundary layers of the hollow fiber. Parameters influencing recoveries were investigated and optimized. Under the optimum conditions, the linear range of lutein and beta-carotene were from 50 to 1,000 ng mL(-1). The correlation coefficients of the calibration curves were > 0.9982, relative standard deviations (n = 5) were between 2.23% and 3.51% and the limits of detection were 0.038 and 0.045 mu g mL(-1) for lutein and beta-carotene, respectively. The proposed method was successfully applied to the extraction and determination of caroteonids in egg yolk with the satisfactory relative recoveries (90.2-101.8%).