Cyclodextrin inclusion effects on fluorescence and fluorimetric properties of the pesticide warfarin

Fluorescence of the pesticide warfarin in aqueous solution was investigated in the presence of α-, β-, γ-cyclodextrins (CyDs) and their methyl derivatives.The fluorescence intensity of warfarin was found to be enhanced in the order of α < γ < β for CyD species, and the methylation of the CyD cavity was found to decrease the fluorescence intensity. Based on the linear regression analysis of the fluorescence increments depending on CyD concentrations, binding constants of warfarin with CyDs were estimated as follow: 552 M1 (β -CyD),285 M1 (dimethyl (β-CyD), 190 M−1 (γ-CyD), 38 M1 (α -CyD). The f luorimetric determination of recovery data of warfarin spiked in irrigation water was improved by using the fluorescence enhancing effects of β-CyD and its methyl derivative.