Spectrophotometric Sequential Injection Analysis System for Estimating the Concentration of Lipid Hydroperoxides in Edible Oils

A sequential injection analysis (SIA) system with spectrophotometric detection was developed as an alternative method for estimating the concentration of lipid hydroperoxides, which are the primary products of the lipid peroxidation process. The lipid hydroperoxide quantification was based on a ferric thiocyanate method. Benzoyl peroxide was used to produce a standard calibration curve for the estimating the lipid hydroperoxide concentrations. The linear range was up to 0.5 mmol/L, for benzoyl peroxide standard, and the limit of detection (3S/N) was 0.015 mmol/L. The relative standard deviation, at 0.3 mmol/L, was 1.3% for 11 injections, and the recoveries were found to be in the range of 97.2–99.5%. The lipid hydroperoxide concentrations in eight edible oils determined using the proposed SIA system were significantly correlated with peroxide values obtained using a conventional American Oil Chemists’ Society’s method (r = 0.987, n = 8, p < 0.01).