Determination of glyphosate and AMPA on polyester‐toner electrophoresis microchip with contactless conductivity detection

Abstract

This paper reports a method for rapid, simple, direct, and reproducible determination of glyphosate and its major metabolite aminomethylphosphonic acid (AMPA). The platform described herein uses polyester-toner microchips incorporating capacitively coupled contactless conductivity detection and electrophoresis separation of the analytes. The polyester-toner microchip presented 150 μm-wide and 12 μm-deep microchannels, with injection and separation lengths of 10 and 40 mm long, respectively. The best results were obtained with 320 kHz frequency, 4.5 Vpp excitation voltage, 80 mmol/L CHES/Tris buffer at pH 8.8, injection in -1.0 kV for 7 s, and separation in -1.5 kV. RSD values related to the peak areas for glyphosate and AMPA were 1.5 and 3.3% and 10.1 and 8.6% for intra- and interchip assays, respectively. The detection limits were 45.1 and 70.5 μmol/L, respectively, without any attempt of preconcentration of the analytes. Finally, the method was applied to river water samples in which glyphosate and AMPA (1.0 mmol/L each) were added. The recovery results were 87.4 and 83.7% for glyphosate and AMPA, respectively. The recovery percentages and LOD values obtained here were similar to others reported in the literature.

Recent advances in amino acid analysis by capillary electromigration methods, 2013–2015

“…The system has been applied to river water sample analyzes in which glyphosate and AMPA (1.0 mmol/L each) were added. The recovery percentages and LOD values obtained were similar to others reported in the literature . Another microchip electrophoresis system including this time LIF detection has been designed for rapid and sensitive analysis of glyphosate and glufosinate residues.…”

Determination of Herbicides and Its Metabolite in Soil and Water Samples by Capillary Electrophoresis-laser Induced Fluorescence Detection Using Microwave-assisted Derivatization

“…Existing analytical methods for the detection of these herbicides in waters and other matrices like soils are mainly based on chromatographic techniques, including liquid chromatography (LC) [7][8][9] and capillary electrophoresis (CE), 10 equipped with different detection devices such as ultraviolet (UV), 11 mass spectrometry (MS), 12,13 and fluorescence detection. [14][15] During the last decade, MS detection with LC separation (LC-MS) has been the technique of choice for the analysis of these herbicides because it provides higher sensitivity and capability to differentiate overlapping peaks with distinct mass-to-charge ratios.…”

“…Another alternative method, CE coupled with laser-induced fluorescence detection (CE-LIF), is also a powerful analytical method as it permits sufficient sensitivity, selectivity and reliablity of determinations in a great majority of common analyses. 10,15 The analytical challenge posed by these herbicides is that they have neither chromophores nor fluorophores groups, preventing their detection by ultraviolet-visible (UV-vis) absorbance or fluorescence. Because of that, derivatization reactions are needed and the most commonly used are 9-fluorenyl methyl chloro formate (FMOC-Cl), [7][8][9] 4-chloro-3,5-dinitrobenzotrifluoride (CNBF), 11 4-fluoro-7-nitro-2,1,3-benzoxadiazole-(NBD-F), 16 p-toluenesulfonyl chloride (TsCl),17 3,6-dimethoxy-9-phenyl-9H-carbazole-1-sulfonyl chloride (DPCS-Cl), 18 sulfoindocyanine succinimidyl ester (Cy5), 14 FITC and DTAF are both fluorescein-based amino-reactive derivatives, which have relatively high absorptivity and excellent fluorescence quantum yield.…”

Plataformas de baixo custo à base de papel para testes imunodiagnósticos e enzimáticos

“…Um dos métodos mais utilizados para a imobilização de anticorpos ou antígenos em superfícies sólidas é por adsorção, primariamente via forças hidrofóbicas [32]. Para os ensaios iniciais, na região de teste foram imobilizados anticorpos anti-IgG de coelho e na região de controle anticorpos IgG de coelho.…”

“…Além disso, o sistema CE-C 4 D pode ser miniaturizado em um microchip [32], o que traz a portabilidade ao sistema, permitindo sua aplicação como um point-of-care testing (POCT) [33][34][35].…”