Solid-phase microextraction coupled with high-performance liquid chromatography for the determination of alkylphenol ethoxylate surfactants in water

Nonionic surfactants of the alkylphenol ethoxylate class are relatively nonvolatile analytes that are typically analyzed by LLE and HPLC or GC after derivatization. Solid-phase microextraction (SPME) has seen many GC applications, but recently the ability to hyphenate SPME with HPLC was investigated. In this paper, a new SPME/HPLC method for analysis of Triton X-100 and other alkylphenol ethoxylates is described. Normal-phase gradient elution with detection by UV absorbance at 220 nm was used for the analysis. Several new coated phases, currently in the developmental stage, were evaluated. New Carbowax/template resin and Carbowax/divinylbenzene coatings allowed successful analysis of alkylphenol ethoxylates with a linear range of 100-0.1 mg/L. These coatings provided the best agreement between the ethoxamer distribution of surfactants after extraction and that in the original surfactant. Limits of detection of the individual ethoxamers were determined to be in the low microgram per liter to submicrogram per liter range. Some applications of the method have been demonstrated for sewage sludge samples.