A new HPLC method for simultaneous analysis of sterols, tocopherols, tocotrienols, and squalene in olive oil deodorizer distillates using a monolithic column with chemometric techniques

Abstract

In this study, a simple, rapid, and special method was developed for the simultaneous quantification of sterols (campesterol, β-sitosterol, and stigmasterol), tocotrienols (α, (β + γ), and δ), tocopherols (α, (β + γ), and δ), and squalene in an olive oil deodorizer distillate using monolithic-chromatographic systems with chemometric techniques. The chromatographic conditions which are the mobile phase polarity (P′), the flow rate (mL min⁻¹) and the temperature of the column compartment (°C) were optimized by using three experimental calibration designs. The optimal chromatographic conditions obtained using a response surface methodology were as follows: the polarity of the mobile phase, 7.00, 6.00, 5.70, and 5.10 for sterols, tocotrienols, tocopherols, and squalene, respectively; the flow rate, 2.50 mL min⁻¹; the temperature of the column compartment, 38.41 °C; and detection, at 202 nm using a diode array detector. For calibrations of all of the bioactive compounds, correlation coefficient values (R²) were obtained at high values close to one and the limit of detection and the limit of quantification were satisfactory. The monolithic column used had a low column pressure despite the high polarity and the high flow rate values of the mobile phases thanks to its porous structure and it made possible an efficient chromatographic separation.