Determination of Glyphosate, Glufosinate, and Their Major Metabolites in Tea Infusions by Dual-Channel Capillary Electrophoresis following Solid-Phase Extraction

Manh Huy Nguyen; Thanh Dam Nguyen; Minh Tuan Vu; Hong Anh Duong; Hung Viet Pham

doi:10.1155/2022/5687025

Determination of Glyphosate, Glufosinate, and Their Major Metabolites in Tea Infusions by Dual-Channel Capillary Electrophoresis following Solid-Phase Extraction

J Anal Methods Chem. 2022 Apr 1:2022:5687025. doi: 10.1155/2022/5687025. eCollection 2022.

Authors

Manh Huy Nguyen¹, Thanh Dam Nguyen¹, Minh Tuan Vu¹, Hong Anh Duong^{1

2}, Hung Viet Pham^{1

2}

Affiliations

¹ Key Laboratory of Analytical Technology for Environmental Quality and Food Safety Control (KLATEFOS), VNU University of Science (VNU-HUS), Vietnam National University, Hanoi (VNU), 334 Nguyen Trai Street, Thanh Xuan District, Hanoi, Vietnam.
² Research Centre for Environmental Technology and Sustainable Development (CETASD), VNU University of Science (VNU-HUS), Vietnam National University, Hanoi (VNU), 334 Nguyen Trai Street, Thanh Xuan District, Hanoi, Vietnam.

Abstract

In this study, two analytical procedures were developed and validated using dual-channel capillary electrophoresis-coupled contactless conductivity detection (CE-C4D) followed by solid-phase extraction (SPE) for simultaneous determination of glyphosate (GLYP), glufosinate (GLUF), and their two major metabolites, aminomethylphosphonic acid (AMPA) and 3-(methylphosphinico) propionic acid (MPPA), respectively, in a popular beverage such as tea infusions. GLYP, GLUF, and AMPA were analyzed in the first channel using background electrolyte (BGE) of 1 mM histidine (His) adjusted to pH 2.75 by acetic acid (Ace). In contrast, MPPA was quantified in the second channel with a BGE of 30 mM His adjusted to pH 6.7 by 3-(N-morpholino) propanesulfonic acid (MOPS) and 10 µM of cetyltrimethylammonium bromide (CTAB). In addition, the samples of tea infusions were treated using SPE with 10 mL of 0.5 mM HCl in methanol as eluent. At the optimized conditions, the method detection limit (MDL) of GLYP, GLUF, AMPA, and MPPA is 0.80, 1.56, 0.56, and 0.54 μg/l, respectively. The methods were then applied to analyze four target compounds in 16 samples of tea infusions. GLYP was found in two infusion samples of oolong tea with concentrations ranging from 5.34 to 10.74 µg/L, and GLUF was recognized in three samples of green tea infusion in the range of 45.1-53.9 µg/L.