Developing Methods for Analyzing Oil Dispersants in Seawater

摘要

An analytical method was sought for determining the concentrations of dispersants in seawater contaminated with oil in both field and laboratory situations. Methods of analysis for surfactants found in the literature included spectrophotometry, gas chromatography (GC), thin-layer chromatography (TLC), and high performance liquid chromatography (HPLC). References to collection, concentration, and cleanup methods included liquid/liquid extractions, gas stripping, and solid sorbents. Of seven dispersants tested, one contained solely anionic surfactants, three contained only nonionic, and three contained both anionic and nonionic surfactants. HPLC normal phase, reverse phase, and ion exchange column techniques were tried. Detection methods included (1) direct measurement of the surfactants by tensammetry and ultraviolet (UV) spectrometry, and (2) derivation of the surfactant with phenyl isocyanate with subsequent measurement by UV spectrometry. The most promising method of those tested was analysis of the phenyl isocyanate derivative of POE nonylphenol by normal phase HPLC using UV spectrometric detection. A method of collection, concentration, and cleanup of seawater solutions of dispersants containing oil was developed using the solid sorbent SEP-PAK C18 cartridge. This sorbent successfully removed compounds that interfered with colorimetric tests.