Studies on the supramolecular interaction between dimethomorph and disulfide linked β-cyclodextrin dimer by spectrofluorimetry and its analytical application.

The supramolecular interaction of disulfide linked β-cyclodextrin (β-CD) dimer and dimethomorph has been studied by spectrofluorimetry. Based on the significant enhancement of the fluorescence intensity of dimethomorph, a new spectrofluorimetric method with high sensitivity and selectivity was developed for the determination of dimethomorph in bulk aqueous in the presence of the disulfide linked β-CD dimer. The inclusion complexation behavior of β-CD dimer with dimethomorph was studied in a KH(2)PO(4)-H(3)PO(4) buffer solution of pH 3.86 at room temperature. The apparent association constant of the complex was 2.25 × 10(4) L/mol. The linear range was 12-7500 ng/mL with the detection limit 3.70 ng/mL, and the limit of quantification was 12.4 ng/mL. The proposed method had been successfully applied to the determination of dimethomorph residues in vegetables with recoveries of 89.0-115%.