Determination of sulfophenylcarboxylic acids in marine samples by solid-phase extraction then high-performance liquid chromatography

Abstract

An analytical method is presented for the determination of sulfophenylcarboxylic acids (SPC) produced by the biodegradation of linear alkylbenzene sulfonates (LAS) in marine samples. Isolation and concentration of the compounds was by solid-phase extraction. The different factors affecting extraction efficiency – packing composition, pH, clean-up, ionic strength, and elution solvents – were studied and optimized. With the proposed method C₄–C₁₃SPC and C₁₀–C₁₃ LAS recoveries varied between 65% and 105%, with standard deviations between 0.1 and 5, respectively, for 100-mL samples and 100 µg L^–1 concentrations of each homolog. Detection limits within the range 0.5 g L^–1 (for C₄SPC) to 1.0 g L^–1 (for C₁₂SPC) were obtained by liquid chromatography with fluorescence detection. This method is the first to be proposed that enables the simultaneous determination of monocarboxylic SPC (C>3) and LAS homologs in marine samples by a simple, sensitive, and specific method giving high recoveries and reproducibility. SPC with from three to twelve carbon atoms in the carboxyl chain have been found in marine water samples.