Flow injection spectrofluorimetric study of the supramolecular interaction between β-cyclodextrin and dequalinium chloride and its analytical application

The supramolecular interaction of dequalinium chloride (DQC) and beta-cyclodextrin has been studied by flow injection spectrofluorimetry. The results showed that P-CD reacted with DQC to form a 1: 1 host:guest complex with an apparent association constant of 4.99 x 10(2) L mol(-1). Based on the enhancement of the fluorescence intensity of DQC, a flow injection sepctrofluoremetric method for the determination of DQC in bulk aqueous solution in the presence of beta-CD was developed. The linear range was 0.0412-30.00 mu g mL(-1). The detection limit was 12.3 ng mL(-1) with a sampling rate of 80 h(-1). There was no interference from the excipients normally used in tablets and serum compositions. The proposed method was successfully applied to the determination of DQC in tablets and serum. (c) 2004 Elsevier B.V. All rights reserved.