Effects of Cyclodextrin on the Polarographic Wave of Oxygen

Abstract

Polarographic reduction wave of oxygen was found to be suppressed by the presence of cyclodextrin (CD) and the suppression of wave by the presence of β -CD was 20 times greater than the presence of α -CD. This phenomerton could be utilized for the determination of trace amount of α - and β -CD.
As shift of E_1/2 of the 1 st wave was not observed by the increase of CD after the maximum was suppressed, it was concluded that α - and β -CD did not form any clathrate compound with O₂ in aqueous solution.
By the analysis of the 2nd wave in acidic and neutral solution, the formation of clathrate compound of H₂O₂ and β -CD with the molar ratio 1: 1 was concluded.
ln alkaline solution, shift of E_1/2 of the 2nd wave was not observed. This fact indicated that the HO₂ ion did not form clathrate compound. The phenomenon was explained by the interaction of HO₂- ion and basicity in the cavity of β -CD.