Determination of herbicide residues in juice by matrix solid-phase dispersion and gas chromatography-mass spectrometry.

A rapid multiresidue method was developed for the determination of 15 herbicides in carrot, grape, and multivegetable juices. The analytical procedure was based on the matrix solid-phase dispersion of juice samples on Florisil, placed in glass columns, and subsequent extraction with ethyl acetate with assisted sonication. The recoveries through the method ranged from 82 to 115% with relative standard deviations equal or lower than 10% for all the herbicides studied. The analysis of samples was accomplished using gas chromatography-mass spectrometry with selected ion monitoring. Spiked blank samples were used as standards to counteract the matrix effect observed in the chromatographic determination. The detection limits ranged from 0.1 to 1.6 microg/l. The developed method was applied to the analysis of herbicide residues in commercial juice samples.