Applications of capillary electrophoresis/laser-induced fluorescence detection to groundwater migration studies.

Capillary electrophoresis has been applied to the determination of groundwater migration based on laser-induced fluorescence (LIF) detection and traditional spectrofluorimetry. Detection limits of injected dye-fluorescent whitening agent (tinopal) in the low ppt ranges have been accomplished with both a spectrofluorometer and with CE/LIF based on the HeCd laser. The real-world problem was the determination of groundwater migration between adjacent Resource Conservation and Recovery Act (RCRA) and Superfund sites. Fluorescent dyes were injected into wells and were discovered in monitoring wells by extracting pads that adsorbed the dye. The methodology based on CE/LIF exhibits increased specificity over existing methodology due to the separation and unique migration time of the dye. Additional studies were aimed at achieving sub-ppt levels in the water directly using solid-phase extraction (SPE) and field-amplified injection techniques.