Analysis of phenylurea and propanil herbicides by solid-phase microextraction and liquid chromatography combined with post-column photochemically induced fluorimetry derivatization and fluorescence detection

This study examines the application of solid-phase microextraction coupled with high performance liquid chromatography combined with post-column photochemically induced fluorimetry derivatization and fluorescence detection (SPME-HPLC-PIF-FD) for the determination of four phenylurea herbicides (monolinuron, diuron, linuron and neburon) and propanil in groundwater. Direct immersion (DI) SPME was applied using a 60 mu m polydimethylsiloxane/divinylbenzene (PDMS/DVB) fiber for the extraction of the pesticides from groundwater samples. An AQUASIL C-18 column (150 mm x 4.6 mm i.d., 5 mu m) was used for separation and determination in HPLC. The method was evaluated with respect to the limits of detection (LODs) and the limits of quantification (LOQs) according to IUPAC. The limits of detection varied between 0.019 mu g L-1 and 0.034 mu g L-1. Limits of quantification ranged between 0.051 mu g L-1 and 0.088 mu g L-1. These values meet the recommended limits for individual pesticides in groundwater (0.1 mu g L-1) established by the EU. Recoveries ranged between 86% and 105% and relative standard deviation values between 2% and 8%. (c) 2007 Elsevier B.V. All rights reserved.