A spectrofluorometer capable of dispersed-spectrum, simultaneous, multiwavelength UV excitation and collection of luminescence has been constructed for the purpose of qualitatively and quantitatively determining aromatic hydrocarbon pollutants dissolved in ocean water. Hydrocarbon fluorescence data produced by this instrument were in the form of excitation/emission matrices, which provide more spectral information about these complex mixtures than is available from conventional excitation or emission fluorescence profiles. Second-order statistical methods were applied to these data to determine low partper-billion concentrations of two primary fluorescent compounds, naphthalene and styrene, found in ocean water exposed to gasoline despite the presence of uncalibrated interference from similar aromatic compounds, the ocean water matrix, and the instrumental background.