Preliminary studies on the mid-infrared analysis of edible oils by direct heating on an ATR diamond crystal

In this work a new, easy and rapid MIR-ATR technique to monitor the thermal stability of oils is presented. The method uses a heated ATR apparatus set at selected temperatures to thermally modify the oils and simultaneously acquire spectra. Because of the larger sample surface to volume ratio, degradation reactions are faster compared to other heating methods. Three different edible oils (sunflower, olive and canola), are subjected to the method. Sunflower oil with or without tocopherol and at three different temperatures (130, 150 and 170 °C) was also analysed. Wavenumbers known to be relevant to oil degradation processes are selected to show the modifications in the spectra over time.