Determination of cyclodextrin content using periodate oxidation by capillary electrophoresis

A simple and general method suitable for the determination of cyclodextrin content in various matrices is described. The proposed method involves selective cleavage of C-C bonds with vicinal hydroxyl groups by means of periodate (Malaprade's reaction). The amount of produced iodate is monitored by capillary electrophoresis. Optimized electrophoretic conditions (20 mM disodium tetraborate with 1 mM tetradecyltrimethylammonium bromide, direct UV detection λ = 200 nm) ensure complete separation of periodate and iodate ions and sufficient sensitivity towards iodate. Under optimized reaction conditions (2-fold excess of periodate, temperature 70°C) reproducible quantitative results were obtained for α-, β- and γ- cyclodextrins as model samples. The proposed method was tested on a real sample of acrylamide - 2(I)-O-allyl-β-CD copolymer. The values of β- cyclodextrin content were compared with those obtained by reference NMR measurement and were found to be identical. (C) 2000 Elsevier Science B.V.