Abstract
Octadecylsilica was employed as reversed-phase HPLC packing material for the simultaneous separation and determination of linear alkylbenzenesulphonates (LAS) and nonylphenol polyethoxylates (NPEO). The role of NaClO4 dissolved in the mobile phase on the separation of LAS and NPEO was investigated: it turned out to affect only the elution volumes of LAS. Alkylphenol polyethoxylates were exhaustively extracted from liquid commercial cleaning products with hexane-acetone mixtures. A procedure for the determination of all the NPEO oligomers enriched from marine waters is presented.