Determination of benzoyl peroxide in wheat flour by ion chromatography with precolumn derivatization

A novel method for the determination of benzoyl peroxide bleach in wheat flour by using high performance anion exchange chromatography (HPIC) after decomposition to benzoic acid was proposed. Benzoyl peroxide was effectively extracted from wheat flour with absolute ethanol by ultrasonication under neutral condition and converted to benzoic acid in the presence of potassium hydroxide solution. The chromatographic separation of benzoic acid was performed on a Dionex OmniPac PAX-100 separation column and the determination by ultraviolet absorbance detection at 222 nm. Good linearity between the concentration of benzoyl peroxide and peak area response nas achieved in the range of 0.12-20 mu g/mL. The detection limit (signal-to-noise ratio 3:1) was 19 ng/mL for benzoyl peroxide. The method has been successfully applied for the analysis of real samples, and the average recoveries for various samples ranged from 81 to 92%.