Thermogravimetric analysis (TGA)
The previously reported method was used to determine the thermal stability of oil (Mokbli et al., 2018) with a Model Q50 TGA (TA instruments, New Castle, DE, USA). Oil samples (about 9 mg) were weighed in platinum sample pans, which were loaded by an autosampler. Samples were heated at the rate of 10 °C/min up to 600 °C under air at the flow rate of 60 ml/min. TA Universal V4.5A software was used to analyze data. Samples were analyzed in triplicate. The thermal stability was determined by the onset temperature of oil decomposition following the previous method (Kalam et al., 2017).