A simple and fast method has been developed and validated to measure glyphosate (GLYP) and aminomethylphosphonic acid (AMPA), which were previously derivatized with 9-fluorenylmethylchloroformate (FMOC-Cl), in maize plants using liquid chromatography (LC) coupled to fluorescence (FLD) and electrospray ionization mass spectrometry (ESI-MS) detection. The method has shown to be consistent, reliable, precise, and efficient. Moreover, the limits of detection (LOD) and quantification (LOQ) reached with the proposed method for GLYP and AMPA are lower than the established maximum residue levels (MRLs). The validated method was applied to quantify GLYP and AMPA in genetically modified (GM) maize foliar treated with the herbicide. It has been found that the GLYP dissipation was mainly due to the progressive dilution effect after herbicide treatment. Finally, it was also observed that the GLYP residue dissipation trend in maize shoot (leaves and stem) tissue determined by LC–ESI-MS matched that determined by liquid scintillation.

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In this work, a liquid chromatography method with diode array and fluorescence detection and electrospray ionization mass spectrometry (LC-DAD-FLD and LC-ESI-MS) has been developed for the determination of residues of resveratrol in all its forms (free isomers and glycosylates) in honey. This procedure involves a solidphase extraction on polymeric cartridges for the isolation of trans/cis-isomers of resveratrol and piceid from diluted honey samples. Chromatographic separation of the analytes was performed in isocratic mode on a C 18 column (150 mm×4.6 mm i.d., 5 μm) operated at 30°C. The mobile phase consisted of a mixture of water with 1% formic acid and acetonitrile (75/25, v/v), and the flow rate was set at 1.0 mL/min. Average analyte recoveries were from 71% to 113% in replica sets of fortified honey samples. The detection limits when using LC-DAD-FLD were between 40 and 120 μg/kg, meanwhile for LC-ESI-MS were between 1.4 and 14.6 μg/kg. The proposed method was applied to the analysis of honey samples collected from treated beehives in experimental apiaries after a preliminary field trial, and they were not found any residues over the detection limits of the studied compounds.