DETERMINATION OF ALKYLATED AND SULFONATED DIPHENYL OXIDE SURFACTANT BY HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY

Methods for the determination of the anionic surfactant Dowfax 8390 ar e described. Dowfax is a complex mixture of various alkylated and sulf onated diphenyl oxides. The primary component of Dowfax is monoalkylat ed disulfonated diphenyl oxide (MADS). This work uses ion pairing chro matography and reverse phase chromatography. Ion pairing chromatograph y provides a simple and fast method for quantitation of the total conc entration of Dowfax surfactant in aqueous solutions. It is shown that suppressed conductivity detection and optical detection at 210 nm have comparable sensitivity. A quantitation limit of 48.4 ppm is achieved with 400 mu l injection. The separation of 11 components in Dowfax is achieved using gradient reverse phase chromatography.