Picomolar detection limits for glyphosate by two‐dimensional column‐coupled isotachophoresis/capillary zone electrophoresis‐mass spectrometry

Abstract

Capillary electrophoresis‐mass spectrometry often lacks sufficient limits of detection for trace substances in the environment due to its low loadability. To overcome this problem, we conducted a feasibility study for column‐coupling isotachophoresis to capillary electrophoresis‐mass spectrometry. The first dimension isotachophoresis preconcentrated the analytes. The column‐coupling of both dimensions was achieved by a hybrid capillary microfluidic chip setup. Reliable analyte transfer by voltage switching was enabled by an in‐chip capacitively coupled contactless conductivity detector placed around the channel of the common section between two T‐shaped crossings in the chip connecting both dimensions. This eliminated the need to calculate the moment of analyte transfer. A commercial capillary electrophoresis‐mass spectrometry instrument with easily installable adaptations operated the setup. Prior to coupling isotachophoresis with capillary zone electrophoresis‐mass spectrometry, both dimensions were optimized individually by simulations and verified experimentally. Both dimensions were able to stack/separate all degradation products of glyphosate, the most important herbicide applied worldwide. The first dimension isotachophoresis also removed phosphate, which is a critical matrix component in many environmental samples. Enrichment and separation of glyphosate and its main degradation product aminomethylphosphonic acid by the two‐dimensional setup provided an excellent limit of detection of 150 pM (25 ng/L) for glyphosate.

Strategies for capillary electrophoresis: Method development and validation for pharmaceutical and biological applications—Updated and completely revised edition

“…As expected, most of the recent reports involving stacking are focused on the application of the approach to various samples, including drinking water [375,376], brain tissue [377], fish [378], meat [379], plants [380], human urine and serum [381], noting that the injection of these samples often requires homogenization, filtration, evaporation, and/or dilution [382,383]. It is also worth mentioning a recent approach by Perrin's group, describing the possibility to combine desalting, protein precipitation, automated liquid-liquid extraction, in-line CE stacking and electrophoretic separation [384], the possibility to combine surfactants and pressure to increase the concentration of analytes (×3000) [385], and the approach described by Graf coupling ITP-CE for the analysis of glyphosate at pM levels [386].…”

Sensitive detection of herbicide residues using field-amplified sample injection coupled with electrokinetic supercharging in flow-gated capillary electrophoresis

“…5,[11][12][13] However, both GlyP and AMPA are highly polar molecules containing phosphate groups in their molecular structures, 10 and thus the detection method is oen limited to liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) aer molecular derivatization with 9-uorenylmethyl chloroformate (FMOC-Cl) for the improved detection sensitivity 10,[14][15][16] although there have been various methods developed, including electrochemical sensors and capillary electrophoresis (CE). 2,7,17 It is worth noting that an extremely low limit of detection for GlyP was reported at 0.12 ng L −1 (0.7 pM) aer the solid phase extraction of 500 mL sea water. 16 To further study the effects of GlyP and its degradation products in various sample sources on human health and environments, novel detection platforms and technologies are highly desired because the presently available techniques have limitations, such as low detection sensitivity, high cost, and time-consuming procedures.…”

“…5,11–13 However, both GlyP and AMPA are highly polar molecules containing phosphate groups in their molecular structures, 10 and thus the detection method is often limited to liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) after molecular derivatization with 9-fluorenylmethyl chloroformate (FMOC–Cl) for the improved detection sensitivity 10,14–16 although there have been various methods developed, including electrochemical sensors and capillary electrophoresis (CE). 2,7,17 It is worth noting that an extremely low limit of detection for GlyP was reported at 0.12 ng L −1 (0.7 pM) after the solid phase extraction of 500 mL sea water. 16…”

Ultrasensitive Fluorescence Platform Based on AgNPs In Situ-Incorporated Zr-MOFs for the Detection of Organophosphorus Pesticides

“…So far, numerous apparatus analysis methods have been established for quantifying pesticide residues such as gas chromatography–mass spectrometry, capillary electrophoresis, and high-performance liquid chromatography (HPLC)-mass spectrometry. − Despite the good sensitivity and dependability of these traditional detection means, a considerable amount of operational time and efforts are required with sophisticated processes . Such inadequacies may prevent their practical usefulness in responding immediately to sudden public emergencies and food poisoning incidents.…”