Pesticide residues found in 98 percent of Canadian honey samples

Determination of glyphosate, AMPA, and glufosinate in honey by online solid-phase extraction-liquid chromatography-tandem mass spectrometry

A new study is the latest evidence that glyphosate herbicides are so pervasive that residues can be found in foods not produced by farmers using glyphosate.

As U.S. regulators continue to dance around the issue of testing foods for residues of glyphosate weed killers, government scientists in Canada have found the pesticide in 197 of 200 samples of honey they examined, Environmental Health News reports, March 22, 2019.

ABSTRACT

A simple method was developed for the simultaneous determination of glyphosate, its main degradation product (aminomethylphosphonic acid), and glufosinate in honey. Aqueous honey solutions were derivatised offline prior to direct analysis of the target analytes using online solid-phase extraction coupled to liquid chromatography-tandem mass spectrometry. Using the developed procedure, accuracies ranging from 95.2% to 105.3% were observed for all analytes at fortification levels of 5, 50, and 150 μg kg−1 with intra-day precisions ranging from 1.6% to 7.2%. The limit of quantitation (LOQ) was 1 μg kg−1 for each analyte. Two hundred honey samples were analysed for the three analytes with AMPA and glyphosate being most frequently detected (99.0% and 98.5% of samples tested, respectively). The concentrations of glyphosate were found to range from <1 to 49.8 μg kg−1 while those of its degradation product ranged from <1 to 50.1 μg kg−1. The ratio of glyphosate to AMPA was found to vary significantly amongst the samples where both analytes were present above the LOQ. Glufosinate was detected in 125 of 200 samples up to a maximum concentration of 33.0 μg kg−1.

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