Development of a specific and sensitive method for the detection of glyphosate pesticide and its metabolite in tea using dummy molecularly imprinted solid-phase extraction coupled with liquid chromatography-tandem quadrupole mass spectrometry

Glyphosate, a widely used herbicide, and its primary metabolite aminomethyl phosphonic acid have been found to cause environmental and ecological issues and threaten human health. The conventional pretreatment method was insufficient for the extraction, concentration, and enrichment of trace substances, resulting in poor specificity. Thus, our objective was to develop a method for glyphosate pesticide detection using dummy molecularly imprinted solid-phase extraction (DMI-SPE) combined with liquid chromatography-tandem quadrupole mass spectrometry (DMI-SPE-LC/MS/MS). The sol-gel method was used to prepare the molecularly imprinted material, using glyphosine as the dummy template molecule, to achieve specific adsorption to glyphosate and reduce costs. The optimized polymerization conditions achieved maximum adsorption of 28.6 µg/mg glyphosate by the molecularly imprinted material. The established DMI-SPE-LC/MS/MS method was used to detect glyphosate and its metabolite (aminomethyl)phosphonic acid in tea. The concentration ranges of glyphosate and (aminomethyl)phosphonic acid (from 0.05 to 4 µg/mL) were linear with correlation coefficients of 0.999 and 0.991, respectively. The recoveries of (aminomethyl)phosphonic acid at three spiked levels ranged from 79.95% to 83.74%, with RSDs between 6.40% and 7.45%, while the recoveries of glyphosate ranged from 98.69% to 106.26%, with RSDs between 0.91% and 1.18%. Our results demonstrate that the developed DMI-SPE-LC/MS/MS method achieves high sensitivity and specific detection of glyphosate and its metabolite (aminomethyl)phosphonic acid in tea matrices.