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

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.