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Microwave (MW) radiation was applied to perform the separation of triacylglycerols (TGs) in oil samples. The novelty of the work lies in the application of MW radiation to assist the separation of several non-polar compounds employing a totally organic mobile phase. Once the influence of the evaporative light scattering detector (ELSD) variables on the sensitivity was optimized, the TGs separation was compared conditioning the column with either a conventional HPLC or a MW oven. Contrary to previous applications in which the mobile phase contained water, the improvement in sensitivity using MW was not as significant in comparison with conventional heating but it allowed a shortening in the retention times of several TGs in about 50% respect elution at room temperature. The method was finally applied for the quantification of most common TGs in almond, tiger nut, and argan oil.

Microwave (MW) radiation was applied to perform the separation of triacylglycerols (TGs) in oil samples. The novelty of the work lies in the application of MW radiation to assist the separation of several non-polar compounds employing a totally organic mobile phase. Once the influence of the evaporative light scattering detector (ELSD) variables on the sensitivity was optimized, the TGs separation was compared conditioning the column with either a conventional HPLC or a MW oven. Contrary to previous applications in which the mobile phase contained water, the improvement in sensitivity using MW was not as significant in comparison with conventional heating but it allowed a shortening in the retention times of several TGs in about 50% respect elution at room temperature. The method was finally applied for the quantification of most common TGs in almond, tiger nut, and argan oil.

The aim of this study was to investigate how triolein and trilinolein are oxidised at elevated temperatures (60-220 °C) in mixtures with octadecane, used as a saturated diluent. The percentages of triolein/trilinolein and octadecane and the oxidation conditions (temperature and time) were chosen according to a statistical central composite design. Heating was performed in a Rancimat equipment. The extent of oxidation was assessed by measuring the peroxide value by titration against potassium iodide, total polar compounds by solid-phase extraction, triacylglycerol polymers by high-performance size-exclusion chromatography, and the losses of triolein and trilinolein by gasliquid chromatography. The results indicated that maximum peroxide values were obtained at intermediate temperatures while the formation of polar compounds and polymers were only significant at temperatures above 140 °C. Interestingly, under the conditions used, concentration of octadecane was not significant in spite of the wide temperature range selected. Finally, independently of the concentration of triolein and trilinolein in the sample, at temperatures below 140 °C only losses of trilinolein were observed.

[ES] Algunos de los métodos analíticos oficiales de la Unión Europea y del Consejo Oleícola Internacional para determinar características de los aceites de oliva no presentan datos sobre su precisión. Con la participación de 22 laboratorios españoles del gobierno y de la industria, se ha llevado a cabo un estudio colaborativo de los métodos analíticos siguientes: absorción de luz UV, a 232 nm (K232), composición de ácidos grasos, trilinoleína, y triglicéridos con número equivalente de carbonos 42 (NEC42). Los datos de repetibilidad y reproducibilidad se han obtenido mediante estudios estadísticos de los resultados según la norma ISO 5275/1986 (E). También se ha estudiado el efecto de la purificación de los aceites en columna de silica gel sobre los valores de K232 y triglicéridos. Finalmente se han comparado las composiciones de ácidos grasos obtenidas utilizando los métodos de reacción con potasa alcohólica en frío y de reacción en caliente con metilato sódico., [EN] Some analytical methods for the determination of olive oil characteristics included in the European Union and International Olive Oil Council regulations lack precision data. To overcome such inconvenient a collaborative trial was set up including 22 laboratories from governmental institutions and industries. UV absorption at 232 nm, fatty acid composition, trilinolein and triglycerides with 42 equivalent carbon number were the tried methods. Repeatability and reproducibility data were obtained using the statistical method included in the International Standard ISO 5275/1986 (E).The effect of oil purification through a silica gel column on K232 and triglycerides was also studied. Finally for fatty acid determination, methylations by cold methanolic potash and by heating with methylated sodium were compared.