Residue Analysis of Glyphosate and Aminomethylphosphonic Acid (AMPA) in Soybean Using Liquid Chromatography Coupled with Tandem Mass Spectrometry
Bibliographic record
Abstract
by mass or tandem mass spectrometry, especially by using electrospray ionization, because they are very polar and easily ionized on this technique.However, just a few methods using mass or tandem mass spectrometry coupled with liquid chromatography have been found in the literature for glyphosate and AMPA analysis.In most of published papers, pre and postcolumn derivatization procedures were employed to analyze the compound derivative by fluorescence detection (Sancho et. al. 1996; Hogendoon et.al. 1999).Vreeken and co-workers developed an analytical method to analyze glyphosate, AMPA and glufosinate in water samples using reversed phase liquid chromatography separation after pre-column derivatization with 9-fluorenylmethyl chloroformate (FMOC-Cl) and detection by tandem mass spectrometry (Vreeken et. al. 1998).Bauer and co-workers detected glyphosate and AMPA in water samples using ion chromatography followed by electrospray with single quadrupole mass spectrometry detection.(Bauer et. al. 1999).The ion chromatography separation without derivatization was also used by Granby and co-workers after clean-up on reversed phase column to analyze glyphosate and AMPA through electrospray ionization/tandem mass spectrometric analysis (Granby et. al. 2003).Goodwin and coworkers studied the electrospray negative ion fragmentation pathways of glyphosate and AMPA using an ion-trap mass spectrometer (Goodwin et.al. 2003).Some other methods found in the literature to analyze glyphosate and AMPA include: capillary electrophoresis (Cikalo et.al. 1996), ion chromatography with conductivity detection (Zhu, et.al. 1999), ion chromatography with fluorescence detection (Patsias et.al. 2001), gas chromatography (Hudzin et.al. 2002), immunoassays (González-Martinez et.al. 2005), nuclear magnetic resonance (Deen et.al. 2002) and integrated pulse amperometry (Ji-Ye et.al. 2001).In this work, we investigated the potential of reversed phase liquid chromatography coupled with electrospray tandem mass spectrometry (LC-ESI/MS/MS) for the quantification of glyphosate and AMPA in soybean spiked samples.In this approach, the compounds were analyzed without derivatization procedures using calibration curves prepared in the matrix, after a simple sample extraction and liquid-liquid partition followed by protein precipitation step with organic solvent to minimize the complexity of the sample.The mobile phase composition and the matrix effects were also investigated to validate the method using a high flow gradient program in a total run time of four minutes for each analyte. Experimental Chemicals and standardsGlyphosate and AMPA standards were obtained from Sigma-Aldrich (Steinheim, Germany).Methanol and dichloromethane HPLC-grade solvents were purchased from J. T. Baker (Deventer, The Netherlands) and ammonium carbonate P.A. was obtained from Merck (Darmstadt, Germany).Purified water was obtained on EASYpure RF System from Barnstead (Dubuque, IA, USA).The stock solutions of glyphosate and AMPA at 500 mg L -1 were prepared by dissolution of the standards in water.The solutions were maintained at 4 o C away from light and stocked in polypropylene tubes to avoid adsorption to glass.The calibration standards were prepared in water or blank soybean extracts for the calibration curves. High-performance liquid chromatographyAn Agilent 1100 series (Agilent Technologies, Waldbronn, Germany) system was operated at flow rate of 1.2 mL min -1 without split using a Zorbax Eclipse ® RDB C8 (Agilent Technologies, www.intechopen.com
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".