Simultaneous determination of β-sitosterol, campesterol, stigmasterol, and brassicasterol in serum by high-performance liquid chromatography with electrochemical detection

Abstract

A simple method for the determination of phytosterols such as β-sitosterol, campesterol, stigmasterol, and brassicasterol has been developed using high-performance liquid chromatography with electrochemical detection (HPLC-ECD). Under optimized conditions, the current peak height was linearly related to the amount of phytosterol injected, ranging from 10 to 200 μmol L⁻¹ (r = 0.999). The relative standard deviation (RSD) was less than 3.1% (100 μmol L⁻¹, n = 6). The detection limit (S/N = 3) of phytosterol was less than 3.4 μmol L⁻¹ (17 pmol). Phytosterols spiked into the control human and rat sera were determined by the present method with recovery rates of more than 80% and RSDs (n = 3) of less than 4.2%. This method has been successfully applied to the monitoring of experimental phytosterolemia in rats induced by a high-phytosterol diet. Taken together, we found this method, which does not require a derivatization step, is both simple and useful for the simultaneous determination of serum phytosterols, providing an alternative tool for the diagnosis of phytosterolemia.