DETERMINATION OF NONIONIC ALIPHATIC AND AROMATIC POLYETHOXYLATED SURFACTANTS IN ENVIRONMENTAL AQUEOUS SAMPLES

Nonionic surfactants of the polyethoxylate types me environmentally re levant because of their ubiquitous presence in raw and treated, munici pal and industrial, wastewaters. Until today the standard methods curr ently used for the routine determination of nonionic surfactants in en vironmental matrices are cumulative methods (BIAS, CTAS, PPAS, TAS), w hich are poorly reliable. particularly in terms of accuracy, and do no t supply and structural information on the ethoxymeric and homolog com position, as well as on the chain length of the hydrophobic moiety. Th is paper describes a specific analytical procedure for the simultaneou s specific determination of polyethoxylate aliphatic (AE) and aromatic (APE) nonionics in aqueous matrices. The analytes were isolated from water samples by solid phase extraction with graphitized carbon black and then derivatized with 1-naphthylisocyanate (NIC). AE and APE were separated bu reversed-phase HPLC combined with fluorescence detection (RP-HLPC/FL). The analytical procedure was applied to the monitoring o f these two classes of surfactants in a municipal sewage treatment pla nt. The method allows rapid, precise and reliable determination of AE and APE in environmental samples at concentrations as low as 0.1 mu dL .