Determination of cholesterol in food samples using dispersive liquid-liquid microextraction followed by HPLC-UV.

A fast, simple, and sensitive sample preparation procedure based on dispersive liquid-liquid microextraction (DLLME) is proposed for the determination of cholesterol in food samples using isocratic reverse phase high performance liquid chromatography (RP-HPLC) and UV detection. The influence of several important parameters on extraction efficiency of cholesterol was evaluated. Under optimized conditions, a linear relationship was obtained between the peak area and the concentration of cholesterol in the range of 0.03-10 microgl(-1). The detection and quantification limits were 0.01 and 0.03 microgl(-1), respectively. Intra-day and inter-day precisions for the analysis of cholesterol were in the range of 1.0-3.1%. The applicability of the proposed method was demonstrated by analyzing cholesterol in milk, egg yolk and olive oil.