Micellar extraction-a new step for enrichment in the analysis of napropamide

The determination of pesticides at trace levels demands an enrichment step due to the insufficient detection limits of most analytical techniques. Aim of this work is the application of the micellar extraction for the preconcentration of napropamide from ultrapure water and natural samples. This surfactant-mediated phase separation uses Genapol X 80 and Genapol X 150 as examples of nonionic surfactants. Combined with the fluorescent detection of the herbicide within the micellar phase, it was possible to achieve detection limits below O.2 pg/1. The various effects like surfactant concentration and addition of salt on the enrichment has been studied. The results demonstrate the usefulness of the cloud point extraction system to extract and preconcentrate napropamide without use of any toxic and expensive organic solvent.