Derivatisation/solid-phase microextraction followed by gas chromatography–mass spectrometry for the analysis of phenoxy acid herbicides in aqueous samples

Abstract Different combinations of derivatisation and solid-phase microextraction followed by gas chromatography–mass spectrometry were optimised and evaluated for the analysis of phenoxy acid herbicides in water. The most successful derivatisation approach was aqueous-phase derivatisation with benzyl bromide. The benzyl esters were extracted most efficiently by the solid-phase microextraction fibre coated with polydimethylsiloxane–divinylbenzene. No carry-over problems were encountered with this fibre upon desorption at 250°C. Detection limits in the ng/l range were obtained, while the relative standard deviations were between 14 and 42%.