Micellar Electrokinetic Capillary Chromatography Method for Direct Determination of Herbicides in Lake Pontchartrain, Louisiana, Sediments

Abstract

A micellar electrokinetic capillary chromatography (MECC) method employing sodium dodecyl sulfate (SDS) as the surfactant has been developed for the separation and quantification of atrazine and 2,4-D in the presence of neutral compounds. The technique exploits the phenomenon of partitioning of analytes between aqueous solution and a micellar pseudostationary phase, along with differences in analyte electrophoretic mobilities. Rapid and efficient separation was evidenced by short migration times and narrow peak widths. Good linearity was obtained between peak height and standard solution concentration with a dynamic range of about 2 orders of magnitude. The detection limit was approximately 2 pg (loaded into the capillary, a 13-nL injection) for both compounds. The developed MECC method was applied to the analysis of sediment samples taken from sites along a linear transect into Lake Pontchartrain, LA, which is directly aligned with the Duncan outfall canal that pumps runoff from the New Orleans metropoli...