Solvent extraction-spectrofluorometric determination of anionic surfactants using acridine orange

A simple and rapid extraction-fluorometric method for the determination of anionic surfactant (AS) at the parts-per-billion (ppb) level is developed. Sodium dodecyl sulfate (SDS), an anionic surfactant after the formation of an ion-associate with acridine orange (ACO), a fluorescent cationic dye was extracted in toluene. The fluorescence intensity (lambda(em): 530 nm, lamb da(exc): 480 nm) of the complex is a direct measure of the SDS concentratio n. The calibration graph is linear in the range of 0-1040 ppb of SDS tin to luene). The relative standard deviation is < +/- 7%. The method is applicab le to river water, pond water and tap water. It is free from interference f rom sodium chloride upto 0.5M concentration level, and also from many catio ns and anions upto a large concentration.