A robust and sensitive method was developed for the simultaneous analysis of metribuzin and quizalofop-p-ethyl residues in potato and soil, based on solid-phase extraction (SPE) coupled to capillary gas chromatography with electron
capture detector (GC-ECD). Residues of two herbicides were extracted from potato and soil with acetone and methanol–water,
followed by SPE to remove coextractives, before analysis by GC-ECD. SPE procedures were performed on Florisil cartridges (500mg,
3mL), the analytes from potato and soil matrix were eluted with petroleum ether-acetic ether (9:1 v/v, 5mL) and petroleum ether-acetic ether (8:2 v/v, 2mL), respectively. Limits of quantification of the method were 0.01mgkg−1, and the mean recoveries ranged from 72.9 to 109.5% with relative standard deviation ranging from 0.7 to 9.2% at the three
spike levels (0.01, 0.1, and 0.5mgkg−1). The proposed method was successfully applied to the analysis of metribuzin and quizalofop-p-ethyl residues in potato and soil samples from an experimental field. Direct confirmation of the analytes in real samples
was achieved by gas chromatography-mass spectrometry (GC–MS).
KeywordsGas chromatography-electron capture detector-Solid-phase extraction-Metribuzin-Quizalofop-p-ethyl
Chromatographia 10/2010; 72(7):701-706. DOI:10.1365/s10337-010-1717-4