Spectrophotometric study of the inclusion complex between β-cyclodextrin and dibenzoyl peroxide and its analytical application

The noncovalent interaction of dibenzoyl peroxide and β-cyclodextin (β-CD) has been studied by spectrophotometry. The mechanism of the inclusion was studied. The results showed that β-CD reacts with dibenzoyl peroxide to form a 2:1 host-guest complex with an apparent formation constant of 2.5 × 104 mol−2 L2. The β-CD reacts with benzoic acid to form a 1:1 host-guest complex with an apparent formation constant of 6.9 × 102 mol−1 L after the dibenzoyl peroxide was reduced by hydroxyl ammonium. Based on the enhancement of the absorbance of dibenzoyl peroxide produced through complex formation, a spectrophotometric method for determination of dibenzoyl peroxide in bulk aqueous solution in the presence of β-CD was developed. A linear relationship between the absorbance and dibenzoyl peroxide concentration was obtained in the range of 0.300-50.0 μg mL−1. Linear regression equation of the calibration graph C = 0.02926 + 53.25 A, with a correlation coefficient of 0.9984 and a relative standard deviation (R.S.D.) of 3.4%. The detection limit was 0.200 μg mL−1, and the recovery was from 98.00 to 105.0%. The proposed method was used to determine the dibenzoyl peroxide in the flour with satisfactory results. The principal advantage of the proposed method is its excellent selectivity based on molecule recognition of β-CD.