An Interlaboratory Comparative Study on the Quantitative Determination of Glyphosate at Low Levels in Wheat Flour

Abstract

In recent years, the use of glyphosate has dramatically increased worldwide, and there is growing concern about contamination of organic products caused by its heavy use on neighboring fields. Glyphosate is found as a residue not only in soil, plants, and groundwater but also in humans and animals. Considering the controversy on glyphosate maximum residue level in foodstuff and the difficulties in its analytical determination, the main purpose of the present paper was to investigate the competence and accuracy of 13 accredited European laboratories in determining glyphosate in wheat flour at a level close to their reporting limit of 10 μg/kg. According to the results of this performance assessment, the laboratories were not able to quantify glyphosate at trace levels. Therefore, their specified reporting limits of 10 μg/kg were not supported by their results, and a reporting limit of around 50 μg/kg of glyphosate in flour seems to be more appropriate to guarantee reliable and robust results. The widespread use of glyphosate and its harmfulness to humans make its detection at trace levels a primary goal for analytical laboratories. This is achievable through the improvement of QA and/or the optimization of the method of analysis used for glyphosate detection.

The Ramazzini Institute 13-week study on glyphosate-based herbicides at human-equivalent dose in Sprague Dawley rats: study design and first in-life endpoints evaluation

“…As the current limit of quantitation of glyphosate in HPLC for pelleted animal feed is 0.050 mg/kg, this represents a technical limiting factor for testing ultra-low doses of glyphosate. As reported by a recent inter laboratory comparative study on the quantitative determination of glyphosate at low levels, caution should be taken when interpreting results if the tested doses of glyphosate are close to the LQ of HPLC [ 47 ].…”

Prenatal Exposure to Glyphosate and Its Environmental Degradate, Aminomethylphosphonic Acid (AMPA), and Preterm Birth: A Nested Case–Control Study in the PROTECT Cohort (Puerto Rico)

“…Over 90% of corn, soy, and canola grown in the United States is genetically modified to be GLY resistant (Fernandez-Cornejo et al 2014), and the market is saturated with more than 750 GBH products (Landrigan and Belpoggi 2018). Long-term and widespread use has yielded detectable GLY residues in foodstuffs, soil, house dust, air, and water (Coupe et al 2012;Curwin et al 2005;Mercurio et al 2014;Silva et al 2018;Simonetti et al 2015;USGS 2019). Therefore, nonoccupational exposure may occur through a variety of pathways including diet, drinking water, and residential use (U.S. EPA 2017).…”

Glyphosate Use, Toxicity and Occurrence in Food

“…Glyphosate is a molecule with high polarity, contributing to its high solubilit ter and insolubility in organic solvents [3]. The particular physical and chemical ties of glyphosate (Table 1), such as the absence of a chromophore or a fluorophor the non-existence of absorption in the ultraviolet region, its low ionization, low v and high hydrophilicity [12], demand the use of complex analytical methodologie detection and quantification of this herbicide in order to achieve the sensitivity a racy requested [6,8,13,14]. The covalent bond between the carbon and the phosphorus atoms is characteristic of these organophosphate compounds and provides glyphosate with several chemical and physical specificities, such as high adsorption, high water solubility and compatibility with other chemical substances [9].…”

“…Glyphosate is a molecule with high polarity, contributing to its high solubility in water and insolubility in organic solvents [3]. The particular physical and chemical properties of glyphosate (Table 1), such as the absence of a chromophore or a fluorophore group, the non-existence of absorption in the ultraviolet region, its low ionization, low volatility and high hydrophilicity [12], demand the use of complex analytical methodologies for the detection and quantification of this herbicide in order to achieve the sensitivity and accuracy requested [6,8,13,14].…”