Uticaj dijamagnetnih dvovalentnih jona metala na autooksidaciju vicinalnih trihidroksilnih fenolnih jedinjenja u vodenim rastvorima

Abstract

In this dissertation the influence of divalent diamagnetic metal ions (Mg(II), Ca(II), Sr(II), Ba(II), Zn(II), Cd(II) and Pb(II)) on vicinal trihydroxy phenolic compounds autoxidation in aqueous solutions was examined. Autoxidation processes of pyrogallol (the simplest compound with appropriate structure), gallic acid and ethyl gallate were studied with the application of UV/Vis spectrophotometry with chemometric data processing, EPR spectroscopy, High-performance liquid chromatography (HPLC) and Mass spectrometry (ESI-MS). It was determined that pH value of solution and presence and type of diamagentic metal ions have great influence on investigated compounds autoxidation processes rates and mechanism. With the aid of applied techniques the structures of transition free radical species and stable autoxidation processes products were determined. Obtained results enabled better understanding of investigated compounds autoxidation processes which is of great importance since gallic acid is found in many plants, while ethyl gallate is used as an antioxidant in food.