Abstract
A simple, sensitive, and rapid method based on ion association, for the determination of FLD has been developed. Flutamide (FLD) can react with Cu(II) to form 1:1 cationic chelate at pH 2.2-7.0 Mclivaine buffer medium, which can further react with anionic surfactants (AS) such as sodium dodecyl sulfate (SDS), sodium lauryl sulfonate (SLS) and sodium dodecylbenzene sulfonate (SDBS) to form 1:1 ion-association complexes. As a result, the resonance Rayleigh scattering (RRS), second-order scattering (SOS) and frequency doubling scattering (FDS) were enhanced to the highest degree. The maximum RRS, SOS and FDS wavelengths of three ion-association complexes were located at 345/345 nm, 610/305 nm and 430/860 nm, respectively. The increments of scattering intensity (Delta I) were directly proportional to the concentration of FLD in certain ranges. The detection limits (3 sigma) of FLD for SDS, SLS and SDBS systems were 1.9 ng ml(-1), 2.1 ng ml(-1) and 2.2 ng ml(-1)(RRS method), 2.4 ng ml(-1), 2.7 ng ml(-1) and 2.6 ng ml(-1) (SOS method) and 2.3 ng ml(-1), 2.4 ng ml(-1) and 2.5 ng ml(-1) (FDS method), separately. The sensitivity of RRS method was higher than those of FDS and SOS methods. The optimum conditions of RRS method and the influence factors, the composition and the reaction mechanism have been discussed. Since the method is highly selective, it does not interference concomitant substances. These methods were applied successfully for the determination of FLD in pharmaceutical formulation and urine samples.