LC-MS/MS characterisation and determination of dansyl chloride derivatised glyphosate, aminomethylphosphonic acid (AMPA), and glufosinate in foods of plant and animal origin

Martins Jansons; Iveta Pugajeva; Vadims Bartkevics; Hark Bahadur Karkee

doi:10.1016/j.jchromb.2021.122779

LC-MS/MS characterisation and determination of dansyl chloride derivatised glyphosate, aminomethylphosphonic acid (AMPA), and glufosinate in foods of plant and animal origin

J Chromatogr B Analyt Technol Biomed Life Sci. 2021 Jul 1:1177:122779. doi: 10.1016/j.jchromb.2021.122779. Epub 2021 May 20.

Authors

Martins Jansons¹, Iveta Pugajeva², Vadims Bartkevics³, Hark Bahadur Karkee⁴

Affiliations

¹ University of Latvia, Faculty of Chemistry, Jelgavas iela 1, Riga LV-1004, Latvia; Institute of Food Safety, Animal Health and Environment "BIOR", Lejupes iela 3, Riga LV-1076, Latvia. Electronic address: martins.jansons@bior.lv.
² Institute of Food Safety, Animal Health and Environment "BIOR", Lejupes iela 3, Riga LV-1076, Latvia.
³ University of Latvia, Faculty of Chemistry, Jelgavas iela 1, Riga LV-1004, Latvia; Institute of Food Safety, Animal Health and Environment "BIOR", Lejupes iela 3, Riga LV-1076, Latvia.
⁴ University of Tartu, Institute of Chemistry, Ravila 14a, 50411 Tartu, Estonia.

PMID: 34098182
DOI: 10.1016/j.jchromb.2021.122779

Abstract

Glyphosate and other polar and acidic pesticides have been particularly studied due to the concerns over widespread and intensive use. The chemical properties of these compounds necessitate use of customised methods, such as derivatisation or ion exchange chromatography. These approaches present a compatibility problem with ESI-MS due to presence of salts and non-volatile compounds. For that reason, a simple procedure has been developed for the extraction, pre-column derivatisation with dansyl chloride (5-(dimethylamino)naphthalene-1-sulfonyl chloride), and mass spectrometric detection of glyphosate, AMPA, and glufosinate after the separation on a C₁₈stationary phase. The dansyl derivatives were characterised with ESI-MS and their separation from derivatisation reagent byproducts was demonstrated with UV absorption detection. Reagent byproducts eluted before the analytes and were separated from the analytes completely, thus the proposed procedure did not contaminate the mass spectrometers. The proposed procedure was evaluated with respect to the matrix effects and extraction efficiency, and was validated with different mass spectrometers for milk, cucumber, honey, porridge formula, bovine kidney and liver matrix. The LOQ was 10 μg kg^-1 for AMPA and glufosinate, and 10-25 μg kg^-1for glyphosate, depending on matrix. Measurement uncertainties ranged from 4 to 44%. Method performance was compared to the QuPPe (Quick Polar Pesticides) procedure in combination with a diethylamino-based column from Waters™. In the case of Orbitrap™ detection, the proposed procedure had a comparable performance to the QuPPe procedure. Although, improved peak shape, higher absolute peak intensity, and lower standard deviation of the calibration curve slope was observed with the proposed procedure. This could be explained by the superior electrospray stability and lower extent of ion suppression.

Keywords: Aminomethylphosphonic acid; Derivatization; Glufosinate; Glyphosate; Massspectrometry; Matrixeffects.

MeSH terms

Aminobutyrates / analysis*
Animals
Cattle
Chromatography, Liquid / methods*
Cucumis sativus / chemistry
Dansyl Compounds / analysis*
Food Analysis
Honey / analysis
Meat / analysis
Organophosphonates / analysis*
Pesticide Residues / analysis*
Tandem Mass Spectrometry / methods

Substances

Aminobutyrates
Dansyl Compounds
Organophosphonates
Pesticide Residues
phosphinothricin
aminomethylphosphonic acid (AMPA)
dansyl chloride