In-situ Fluorescence Detection of Polycyclic Aromatic Hudrocarbons Following Preconcentration on Alkylated Silica Adsorbents

摘要

In-situ detection of analytes sorbed to alkylated silica is found to be a sensitive and quantitative method for the determination of trace concentration levels of PAH compounds in aqueous solution. The method is developed using pyrene as a model analyte preconcentrated from methanol-water solutions onto C18 chromatographic silica, a material which is compatible with in-situ fluorescence detection of sorbed species. Adjustment of solution phase composition is shown to control the preconcentration factor by three orders of magnitude, predictable by chromatographic retention results. Sensitivity increases for fluorescence detection of pyrene within practical limits were as large as 245, leading to a 200-fold reduction in detectable solution concentrations to levels as low as 0.17 parts-per-trillion. The technique could be readily extended to the determination of a variety of PAH compounds in aqueous environments, where samples would be prepared by dilution with small quantities of methanol prior to their preconcentration and measurement. In-situ fluorescence detection has also been found to be suitable for determining the retention of solutes in regions of solvent composition where chromatographic measurements would prove difficult.