1
|
Štěpánová S, Kašička V. Determination of physicochemical parameters of (bio)molecules and (bio)particles by capillary electromigration methods. J Sep Sci 2024; 47:e2400174. [PMID: 38867483 DOI: 10.1002/jssc.202400174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2024] [Revised: 05/03/2024] [Accepted: 05/10/2024] [Indexed: 06/14/2024]
Abstract
The review provides an overview of recent developments and applications of capillary electromigration (CE) methods for the determination of important physicochemical parameters of various (bio)molecules and (bio)particles. These parameters include actual and limiting (absolute) ionic mobilities, effective electrophoretic mobilities, effective charges, isoelectric points, electrokinetic potentials, hydrodynamic radii, diffusion coefficients, relative molecular masses, acidity (ionization) constants, binding constants and stoichiometry of (bio)molecular complexes, changes of Gibbs free energy, enthalpy and entropy and rate constants of chemical reactions and interactions, retention factors and partition and distribution coefficients. For the determination of these parameters, the following CE methods are employed: zone electrophoresis in a free solution or in sieving media, isotachophoresis, isoelectric focusing, affinity electrophoresis, electrokinetic chromatography, and electrochromatography. In the individual sections, the procedures for the determination of the above parameters by the particular CE methods are described.
Collapse
Affiliation(s)
- Sille Štěpánová
- Electromigration methods, Institute of Organic Chemistry and Biochemistry, The Czech Academy of Sciences, Prague, Czech Republic
| | - Václav Kašička
- Electromigration methods, Institute of Organic Chemistry and Biochemistry, The Czech Academy of Sciences, Prague, Czech Republic
| |
Collapse
|
2
|
Masci M, Caproni R, Nevigato T. Chromatographic Methods for the Determination of Glyphosate in Cereals Together with a Discussion of Its Occurrence, Accumulation, Fate, Degradation, and Regulatory Status. Methods Protoc 2024; 7:38. [PMID: 38804332 PMCID: PMC11130892 DOI: 10.3390/mps7030038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2024] [Revised: 04/19/2024] [Accepted: 04/29/2024] [Indexed: 05/29/2024] Open
Abstract
The European Union's recent decision to renew the authorization for the use of glyphosate until 15 December 2033 has stimulated scientific discussion all around the world regarding its toxicity or otherwise for humans. Glyphosate is a chemical of which millions of tons have been used in the last 50 years worldwide to dry out weeds in cultivated fields and greenhouses and on roadsides. Concern has been raised in many areas about its possible presence in the food chain and its consequent adverse effects on health. Both aspects that argue in favor of toxicity and those that instead may indicate limited toxicity of glyphosate are discussed here. The widespread debate that has been generated requires further investigations and field measurements to understand glyphosate's fate once dispersed in the environment and its concentration in the food chain. Hence, there is a need for validated analytical methods that are available to analysts in the field. In the present review, methods for the analytical determination of glyphosate and its main metabolite, AMPA, are discussed, with a specific focus on chromatographic techniques applied to cereal products. The experimental procedures are explained in detail, including the cleanup, derivatization, and instrumental conditions, to give the laboratories involved enough information to proceed with the implementation of this line of analysis. The prevalent chromatographic methods used are LC-MS/MS, GC-MS/SIM, and GC-MS/MS, but sufficient indications are also given to those laboratories that wish to use the better performing high-resolution MS or the simpler HPLC-FLD, HPLC-UV, GC-NPD, and GC-FPD techniques for screening purposes. The concentrations of glyphosate from the literature measured in wheat, corn, barley, rye, oats, soybean, and cereal-based foods are reported, together with its regulatory status in various parts of the world and its accumulation mechanism. As for its accumulation in cereals, the available data show that glyphosate tends to accumulate more in wholemeal flours than in refined ones, that its concentration in the product strictly depends on the treatment period (the closer it is to the time of harvesting, the higher the concentration), and that in cold climates, the herbicide tends to persist in the soil for a long time.
Collapse
Affiliation(s)
- Maurizio Masci
- Council for Agricultural Research and Economics (CREA), Research Centre for Food and Nutrition, via Ardeatina 546, 00178 Rome, Italy (T.N.)
| | | | | |
Collapse
|
3
|
Štěpánová S, Andris E, Gutten O, Buděšínský M, Dejmek M, Břehová P, Rulíšek L, Kašička V. Acidity constants and protonation sites of cyclic dinucleotides determined by capillary electrophoresis, quantum chemical calculations, and NMR spectroscopy. Electrophoresis 2024; 45:687-705. [PMID: 38059733 DOI: 10.1002/elps.202300232] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2023] [Revised: 11/11/2023] [Accepted: 11/18/2023] [Indexed: 12/08/2023]
Abstract
Cyclic dinucleotides (CDNs) are important second messengers in bacteria and eukaryotes. Detailed characterization of their physicochemical properties is a prerequisite for understanding their biological functions. Herein, we examine acid-base and electromigration properties of selected CDNs employing capillary electrophoresis (CE), density functional theory (DFT), and nuclear magnetic resonance (NMR) spectroscopy to provide benchmark pKa values, as well as to unambiguously determine the protonation sites. Acidity constants (pKa) of the NH+ moieties of adenine and guanine bases and actual and limiting ionic mobilities of CDNs were determined by nonlinear regression analysis of the pH dependence of their effective electrophoretic mobilities measured by CE in aqueous background electrolytes in a wide pH range (0.98-11.48), at constant temperature (25°C), and constant ionic strength (25 mM). The thermodynamic pKa values were found to be in the range 3.31-4.56 for adenine and 2.28-3.61 for guanine bases, whereas the pKa of enol group of guanine base was in the range 10.21-10.40. Except for systematic shifts of ∼2 pKa, the pKa values calculated by the DFT-D3//COSMO-RS composite protocol that included large-scale conformational sampling and "cross-morphing" were in a relatively good agreement with the pKas determined by CE and predict N1 atom of adenine and N7 atom of guanine as the protonation sites. The protonation of the N1 atom of adenine and N7 atom of guanine in acidic background electrolytes (BGEs) and the dissociation of the enol group of guanine in alkaline BGEs was confirmed also by NMR spectroscopy.
Collapse
Affiliation(s)
- Sille Štěpánová
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Prague, Czech Republic
| | - Erik Andris
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Prague, Czech Republic
| | - Ondrej Gutten
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Prague, Czech Republic
| | - Miloš Buděšínský
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Prague, Czech Republic
| | - Milan Dejmek
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Prague, Czech Republic
| | - Petra Břehová
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Prague, Czech Republic
| | - Lubomír Rulíšek
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Prague, Czech Republic
| | - Václav Kašička
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Prague, Czech Republic
| |
Collapse
|
4
|
Hajduk A, Ulrich N. Determination of acidity constants of pyridines, imidazoles, and oximes by capillary electrophoresis. Electrophoresis 2023; 44:1353-1360. [PMID: 37377077 DOI: 10.1002/elps.202300037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Revised: 06/11/2023] [Accepted: 06/12/2023] [Indexed: 06/29/2023]
Abstract
The acidity constant in the form of pKa is one of the most important physicochemical quantities. There are prediction tools available for calculating the pKa , but they only deliver precise calculated values for a relatively small set of chemicals. For complex structures with multiple functional groups in particular, the error in the predicted pKa is high due to the application domain of the corresponding models. Thus, we aim to enlarge the dataset of experimentally determined pKa values using capillary electrophoresis. We, therefore, selected various pyridines, imidazoles, and oximes to determine the pKa values using the internal standard approach and the classical method. Especially oximes were not investigated in the past, and predictions for them include larger errors. Thus, our experimentally determined values could contribute to an improved understanding of various functional groups impacting the pKa values and serve as additional datasets to develop improved pKa prediction tools.
Collapse
Affiliation(s)
- Anna Hajduk
- Department of Ecological Chemistry, Helmholtz Centre for Environmental Research - UFZ, Leipzig, Germany
| | - Nadin Ulrich
- Department of Ecological Chemistry, Helmholtz Centre for Environmental Research - UFZ, Leipzig, Germany
| |
Collapse
|
5
|
Wimmer B, Langarica-Fuentes A, Schwarz E, Kleindienst S, Huhn C, Pagel H. Mechanistic modeling indicates rapid glyphosate dissipation and sorption-driven persistence of its metabolite AMPA in soil. JOURNAL OF ENVIRONMENTAL QUALITY 2023; 52:393-405. [PMID: 36417923 DOI: 10.1002/jeq2.20437] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Accepted: 11/04/2022] [Indexed: 06/16/2023]
Abstract
Residual concentrations of glyphosate and its main transformation product aminomethylphosphonic acid (AMPA) are often observed in soils. The factors controlling their biodegradation are currently not well understood. We analyzed sorption-limited biodegradation of glyphosate and AMPA in soil with a set of microcosm experiments. A mechanistic model that accounts for equilibrium and kinetic sorption facilitated interpretation of the experimental results. Both compounds showed a biphasic dissipation with an initial fast (up to Days 7-10) and subsequent slower transformation rate, pointing to sorption-limited degradation. Glyphosate transformation was well described by considering only equilibrium sorption. Model simulations suggested that only 0.02-0.13% of total glyphosate was present in the soil solution and thus bioavailable. Glyphosate transformation was rapid in solution (time required for 50 % dissipation of the total initially added chemical [DT50 ] = 3.9 min), and, despite strong equilibrium sorption, total glyphosate in soil dissipated quickly (DT50 = 2.4 d). Aminomethylphosphonic acid dissipation kinetics could only be described when considering both equilibrium and kinetic sorption. In comparison to glyphosate, the model simulations showed that a higher proportion of total AMPA was dissolved and directly bioavailable (0.27-3.32%), but biodegradation of dissolved AMPA was slower (DT50 = 1.9 h). The model-based data interpretation suggests that kinetic sorption strongly reduces AMPA bioavailability, leading to increased AMPA persistence in soil (DT50 = 12 d). Thus, strong sorption combined with rapid degradation points to low risks of glyphosate leaching by vertical transport through soil in the absence of preferential flow. Ecotoxicological effects on soil microorganisms might be reduced. In contrast, AMPA persists, rendering these risks more likely.
Collapse
Affiliation(s)
- Benedikt Wimmer
- Institute of Physical and Theoretical Chemistry, Eberhard Karls Univ., Tübingen, Germany
| | - Adrian Langarica-Fuentes
- Center for Applied Geosciences/Geo- and Environmental Research Center, Eberhard Karls Univ., Tübingen, Germany
| | - Erik Schwarz
- Dep. of Biogeophysics, Institute of Soil Science and Land Evaluation, Univ. of Hohenheim, Stuttgart, Germany
- Dep. of Physical Geography and Bolin Centre for Climate Research, Stockholm Univ., Stockholm, Sweden
| | - Sara Kleindienst
- Center for Applied Geosciences/Geo- and Environmental Research Center, Eberhard Karls Univ., Tübingen, Germany
- Dep. of Environmental Microbiology, Institute for Sanitary Engineering, Water Quality and Solid Waste Management (ISWA), Univ. of Stuttgart, Stuttgart, Germany
| | - Carolin Huhn
- Institute of Physical and Theoretical Chemistry, Eberhard Karls Univ., Tübingen, Germany
| | - Holger Pagel
- Dep. of Biogeophysics, Institute of Soil Science and Land Evaluation, Univ. of Hohenheim, Stuttgart, Germany
| |
Collapse
|
6
|
Graf HG, Rudisch BM, Ude L, Müller L, Huhn C. Picomolar detection limits for glyphosate by two-dimensional column-coupled isotachophoresis/capillary zone electrophoresis-mass spectrometry. J Sep Sci 2022; 45:3887-3899. [PMID: 35998068 DOI: 10.1002/jssc.202200519] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Revised: 08/18/2022] [Accepted: 08/19/2022] [Indexed: 11/09/2022]
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 2D setup provided an excellent limit of detection of 150 pM (25 ng/L) for glyphosate. This article is protected by copyright. All rights reserved.
Collapse
Affiliation(s)
- Hannes Georg Graf
- Institute of Physical and Theoretical Chemistry, Eberhard Karls Universität Tübingen, Tübingen, Germany
| | | | - Lukas Ude
- Institute of Physical and Theoretical Chemistry, Eberhard Karls Universität Tübingen, Tübingen, Germany
| | - Linda Müller
- Institute of Physical and Theoretical Chemistry, Eberhard Karls Universität Tübingen, Tübingen, Germany
| | - Carolin Huhn
- Institute of Physical and Theoretical Chemistry, Eberhard Karls Universität Tübingen, Tübingen, Germany
| |
Collapse
|
7
|
Nguyen MH, Nguyen TD, Vu MT, Duong HA, Pham HV. Determination of Glyphosate, Glufosinate, and Their Major Metabolites in Tea Infusions by Dual-Channel Capillary Electrophoresis following Solid-Phase Extraction. JOURNAL OF ANALYTICAL METHODS IN CHEMISTRY 2022; 2022:5687025. [PMID: 35402060 PMCID: PMC8993582 DOI: 10.1155/2022/5687025] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Accepted: 03/05/2022] [Indexed: 06/14/2023]
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.
Collapse
Affiliation(s)
- Manh Huy Nguyen
- 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
| | - Thanh Dam Nguyen
- 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
| | - Minh Tuan Vu
- 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
| | - Hong Anh Duong
- 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
- 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
| | - Hung Viet Pham
- 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
- 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
| |
Collapse
|