Application of micro-TLC to the total antioxidant potential (TAP) measurement.

DPPH is commonly applied for estimation of antioxidant capacity of single and complex biological samples, and changes colour from purple to yellow during reduction to DPPH-H. Importantly, for some samples, for example coloured foods, such reaction cannot be used because of interference from pigments. Therefore, the number of reported quantitative protocols involving off- or on-line sample reaction with DPPH are based on chromatographic separation of target components.