A significant problem associated with the commercial acceptance of biodiesel is poor oxidative stability. Previous studies indicate that different types of biodiesel have different natural levels of oxidative stability. Moreover, the effect of both natural and synthetic antioxidants on biodiesel stability differs depending on composition. Therefore, understanding the mechanism of antioxidant activity and developing new antioxidants to improve fuel oxidative stability are important.

This study develops a robust analytical method to determine natural antioxidant content in biodiesel, and investigates the effect of composition and minor components, such as sterols, natural antioxidant, and free and bound glycerin, on the effectiveness of synthetic antioxidant. Additionally, the effect of selected antioxidants on oxidative stability of biodiesel under long-term indoor and outdoor storage will be described.