An automatic FIA-CL method for the determination of antioxidant activity of edible oils based on peroxyoxalate chemiluminescence

The antioxidant activity of oils is an important parameter that determines oils' nutritional value and quality. To date, the methods for the determination of the antioxidant activity of oils are performed under batch conditions, therefore, they have large turnaround times and are labor-intensive. In this work, we describe the first automated method for the determination of the antioxidant activity of edible oils by resorting to the benefits of Flow Injection Analysis (FIA) and the high sensitivity of chemiluminescence (CL) detection. In the developed method, we used the chemiluminescent reaction of bis(2,4, 6-trichlorophenyl) oxalate with the reactive oxygen species produced by the catalytic decomposition of H2O2 by Mn(II) ions. The antioxidants present in the sample scavenge the reactive oxygen species and inhibit the light reaction. 1-Amino-pyrene was used as fluorophore and 1-methyl-imidazole as base catalyst in the reaction. Method validation and application to real samples showed that the analytical features of the method are very satisfactory in terms of linearity of response-lines of standard antioxidant compounds (R2 = 0.98-0.999), precision (%RSD = 0.85-1.9%) and accuracy (%recovery = 91-109%), suggesting that the developed assay could serve as an efficient tool to the routine screening of antioxidant properties in edible oils.