Enhanced spectrofluorimetric determination of the pesticide warfarin by means of the inclusion complex with β-cyclodextrin

The warfarin-beta-cyclodextrin inclusion complex alters the luminescent properties of warfarin. This feature allows the use of a spectrofluorimetric method for its determination that gives improved analytical performance. The spectral changes associated with the inclusion process allowed a value of 160 l mol-1 to be obtained for the complexation constant. Fluorescence intensity is linearly related to warfarin concentration for a quantification limit of from 0.2 to 4 micrograms ml-1. The relative standard deviation at the 1.5 microgram ml-1 level is 3.5%. The method was applied satisfactorily to the determination of warfarin in irrigation water.