1
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Herter SO, Haase H, Koch M. First Synthesis of Ergotamine- 13CD 3 and Ergotaminine- 13CD 3 from Unlabeled Ergotamine. Toxins (Basel) 2024; 16:199. [PMID: 38668624 PMCID: PMC11053779 DOI: 10.3390/toxins16040199] [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: 03/26/2024] [Revised: 04/16/2024] [Accepted: 04/17/2024] [Indexed: 04/29/2024] Open
Abstract
Ergot alkaloids (EAs) formed by Claviceps fungi are one of the most common food contaminants worldwide, affecting cereals such as rye, wheat, and barley. To accurately determine the level of contamination and to monitor EAs maximum levels set by the European Union, the six most common EAs (so-called priority EAs) and their corresponding epimers are quantified using high-performance liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS). The quantification of EAs in complex food matrices without appropriate internal standards is challenging but currently carried out in the standard method EN 17425:2021 due to their commercial unavailability. To address the need for isotopically labeled EAs, we focus on two semi-synthetic approaches for the synthesis of these reference standards. Therefore, we investigate the feasibility of the N6-demethylation of native ergotamine to yield norergotamine, which can subsequently be remethylated with an isotopically labeled methylating reagent, such as iodomethane (13CD3-I), to yield isotopically labeled ergotamine and its C8-epimer ergotaminine. Testing the isotopically labeled ergotamine/-inine against native ergotamine/-inine with HPLC coupled to high-resolution HR-MS/MS proved the structure of ergotamine-13CD3 and ergotaminine-13CD3. Thus, for the first time, we can describe their synthesis from unlabeled, native ergotamine. Furthermore, this approach is promising as a universal way to synthesize other isotopically labeled EAs.
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Affiliation(s)
- Sven-Oliver Herter
- Division 1.7, Organic Trace and Food Analysis, Bundesanstalt für Materialforschung und-prüfung (BAM), Richard-Willstätter-Str. 11, 12489 Berlin, Germany;
| | - Hajo Haase
- Department of Food Chemistry and Toxicology, Technische Universität Berlin, Gustav-Meyer-Allee 25, 13355 Berlin, Germany;
| | - Matthias Koch
- Division 1.7, Organic Trace and Food Analysis, Bundesanstalt für Materialforschung und-prüfung (BAM), Richard-Willstätter-Str. 11, 12489 Berlin, Germany;
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2
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Yue ZX, Gu YX, Yan TC, Liu FM, Cao J, Ye LH. Phase Ⅰ and phase Ⅱ metabolic studies of Citrus flavonoids based on electrochemical simulation and in vitro methods by EC-Q-TOF/MS and HPLC-Q-TOF/MS. Food Chem 2022; 380:132202. [DOI: 10.1016/j.foodchem.2022.132202] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Revised: 01/05/2022] [Accepted: 01/17/2022] [Indexed: 02/07/2023]
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3
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Najmi AA, Bischoff R, Permentier HP. N-Dealkylation of Amines. Molecules 2022; 27:molecules27103293. [PMID: 35630770 PMCID: PMC9146227 DOI: 10.3390/molecules27103293] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Revised: 05/03/2022] [Accepted: 05/08/2022] [Indexed: 02/01/2023] Open
Abstract
N-dealkylation, the removal of an N-alkyl group from an amine, is an important chemical transformation which provides routes for the synthesis of a wide range of pharmaceuticals, agrochemicals, bulk and fine chemicals. N-dealkylation of amines is also an important in vivo metabolic pathway in the metabolism of xenobiotics. Identification and synthesis of drug metabolites such as N-dealkylated metabolites are necessary throughout all phases of drug development studies. In this review, different approaches for the N-dealkylation of amines including chemical, catalytic, electrochemical, photochemical and enzymatic methods will be discussed.
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4
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Göldner V, Fangmeyer J, Karst U. Development of an electrochemical flow-through cell for the fast and easy generation of isotopically labeled metabolite standards. Drug Test Anal 2021; 14:262-268. [PMID: 34634186 DOI: 10.1002/dta.3175] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Accepted: 09/30/2021] [Indexed: 02/06/2023]
Abstract
In drug development, metabolite standards of new chemical entities are required for a comprehensive safety evaluation. Stable isotope-labeled internal metabolite standards at the milligram scale, which are difficult and expensive to synthesize in common bottom-up approaches, are necessary for metabolite quantification using liquid chromatography/mass spectrometry. A preparative electrochemical flow-through cell is presented here as a powerful tool for the cheap and straightforward synthesis of milligram amounts of isotopically labeled metabolite standards. The developed cell scales up established, so-called "coulometric" electrochemical cells. Problems like electrode fouling and cross contamination between syntheses are addressed by the use of exchangeable working electrodes. The applicability of the developed cell for the synthesis of metabolite standards is demonstrated using isotopically labeled acetaminophen as a model system for the generation of a biologically relevant phase II metabolite.
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Affiliation(s)
- Valentin Göldner
- Institute of Inorganic and Analytical Chemistry, University of Münster, Münster, Germany.,International Graduate School for Battery Chemistry, Characterization, Analysis, Recycling and Application (BACCARA), University of Münster, Münster, Germany
| | - Jens Fangmeyer
- Institute of Inorganic and Analytical Chemistry, University of Münster, Münster, Germany
| | - Uwe Karst
- Institute of Inorganic and Analytical Chemistry, University of Münster, Münster, Germany.,International Graduate School for Battery Chemistry, Characterization, Analysis, Recycling and Application (BACCARA), University of Münster, Münster, Germany
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5
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Potęga A, Paczkowski S, Paluszkiewicz E, Mazerska Z. Electrochemical simulation of metabolic reduction and conjugation reactions of unsymmetrical bisacridine antitumor agents, C-2028 and C-2053. J Pharm Biomed Anal 2021; 197:113970. [PMID: 33618132 DOI: 10.1016/j.jpba.2021.113970] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Revised: 01/15/2021] [Accepted: 02/10/2021] [Indexed: 12/15/2022]
Abstract
Electrochemistry (EC) coupled with analysis techniques such as liquid chromatography (LC) and mass spectrometry (MS) has been developed as a powerful tool for drug metabolism simulation. The application of EC in metabolic studies is particularly favourable due to the low matrix contribution compared to in vitro or in vivo biological models. In this paper, the EC(/LC)/MS system was applied to simulate phase I metabolism of the representative two unsymmetrical bisacridines (UAs), named C-2028 and C-2053, which contain nitroaromatic group susceptible to reductive transformations. UAs are a novel potent class of antitumor agents of extraordinary structures that may be useful in the treatment of difficult for therapy human solid tumors such as breast, colon, prostate, and pancreatic tumors. It is considered that the biological action of these compounds may be due to the redox properties of the nitroaromatic group. At first, the relevant conditions for the electrochemical conversion and product identification process, including the electrode potential range, electrolyte composition, and working electrode material, were optimized with the application of 1-nitroacridine as a model compound. Electrochemical simulation of C-2028 and C-2053 reductive metabolism resulted in the generation of six and five products, respectively. The formation of hydroxylamine m/z [M+H-14]+, amine m/z [M+H-30]+, and novel N-oxide m/z [M+H-18]+ species from UAs was demonstrated. Furthermore, both studied compounds were shown to be stable, retaining their dimeric forms, during electrochemical experiments. The electrochemical method also indicated the susceptibility of C-2028 to phase II metabolic reactions. The respective glutathione and dithiothreitol adducts of C-2028 were identified as ions at m/z 873 and m/z 720. In conclusion, the electrochemical reductive transformations of antitumor UAs allowed for the synthesis of new reactive intermediate forms permitting the study of their interactions with biologically crucial molecules.
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Affiliation(s)
- Agnieszka Potęga
- Department of Pharmaceutical Technology and Biochemistry, Faculty of Chemistry, Gdańsk University of Technology, Gabriela Narutowicza St. 11/12, Gdańsk, 80-233, Poland.
| | - Szymon Paczkowski
- Department of Pharmaceutical Technology and Biochemistry, Faculty of Chemistry, Gdańsk University of Technology, Gabriela Narutowicza St. 11/12, Gdańsk, 80-233, Poland.
| | - Ewa Paluszkiewicz
- Department of Pharmaceutical Technology and Biochemistry, Faculty of Chemistry, Gdańsk University of Technology, Gabriela Narutowicza St. 11/12, Gdańsk, 80-233, Poland.
| | - Zofia Mazerska
- Department of Pharmaceutical Technology and Biochemistry, Faculty of Chemistry, Gdańsk University of Technology, Gabriela Narutowicza St. 11/12, Gdańsk, 80-233, Poland.
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6
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Affiliation(s)
- Muhammad H. Rahman
- School of PharmacyUniversity of Birmingham Edgbaston B15 2TT United Kingdom
| | - Mandeep K. Bal
- Faculty of Science and EngineeringManchester Metropolitan University Chester Street Manchester M1 5GD United Kingdom
| | - Alan M. Jones
- School of PharmacyUniversity of Birmingham Edgbaston B15 2TT United Kingdom
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7
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Navarro Suarez L, Brückner L, Rohn S. Electrochemical Oxidation of Primary Bile Acids: A Tool for Simulating Their Oxidative Metabolism? Int J Mol Sci 2018; 19:E2491. [PMID: 30142907 PMCID: PMC6165074 DOI: 10.3390/ijms19092491] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Revised: 08/16/2018] [Accepted: 08/18/2018] [Indexed: 01/14/2023] Open
Abstract
Bile acids are a subgroup of sterols and important products of cholesterol catabolism in mammalian organisms. Modifications (e.g., oxidation and 7-dehydroxylation) are predominantly exerted by the intestinal microbiota. Bile acids can be found in almost all living organisms, and their concentration and metabolism can be used for the assessment of the pathological and nutritional status of an organism. Electrochemical oxidation is a rapid, relatively inexpensive approach to simulate natural metabolic redox processes in vitro. This technique further allows the identification of oxidative degradation pathways of individual substances, as well as the demonstration of binding studies of generated oxidation products with biologically relevant molecules. When coupling an electrochemical and a high-resolution mass spectrometric system, oxidation products can be generated and identified directly by non-targeted ESI-MS. Here, a method for the generation of oxidation products of the primary bile acids cholic acid and chenodeoxycholic acid was exemplarily developed. Most products and the highest intensities were observed at a pH value of 6. For cholic acid, a high potential of 3 V was necessary, while for chenodeoxycholic acid, a potential of 2.4 V led to a higher number of oxidation products. In a second approach, a binding study with glutathione was performed to simulate phase II metabolism. It was possible to detect signals of free glutathione, free bile acids, and adducts of both reactants. As the resulting mass spectra also showed some new signals of the oxidized bile acid, which could not be observed without glutathione, it can be assumed that glutathione is able to bind reactive oxidation species before reacting with other products.
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Affiliation(s)
- Laura Navarro Suarez
- Hamburg School of Food Science, Institute of Food Chemistry, University of Hamburg, Martin-Luther-King-Platz 6, 20146 Hamburg, Germany.
| | - Lea Brückner
- Hamburg School of Food Science, Institute of Food Chemistry, University of Hamburg, Martin-Luther-King-Platz 6, 20146 Hamburg, Germany.
| | - Sascha Rohn
- Hamburg School of Food Science, Institute of Food Chemistry, University of Hamburg, Martin-Luther-King-Platz 6, 20146 Hamburg, Germany.
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8
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Frensemeier LM, Mayr J, Koellensperger G, Keppler BK, Kowol CR, Karst U. Structure elucidation and quantification of the reduction products of anticancer Pt(iv) prodrugs by electrochemistry/mass spectrometry (EC-MS). Analyst 2018; 143:1997-2001. [PMID: 29629473 PMCID: PMC5933000 DOI: 10.1039/c8an00258d] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Pt(iv) prodrugs are a class of promising anticancer agents, which are activated by reduction to the active Pt(ii) species. Consequently, the reduction process is a crucial parameter. Herein, a new approach using electrochemistry (EC) coupled to liquid chromatography (LC) and electrospray ionization-mass spectrometry (ESI-MS) or inductively coupled plasma (ICP)-MS was applied. This enabled getting insights into the differences in the reduction and ligand release of platinum(iv) complexes with varying equatorial core structures.
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Affiliation(s)
- L M Frensemeier
- Institute of Inorganic and Analytical Chemistry, University of Münster, Corrensstr. 28/30, 48149 Münster, Germany.
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9
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Reinen J, Smit M, Wenker M. Evaluation of Strategies for the Assessment of Drug–Drug Interactions Involving Cytochrome P450 Enzymes. Eur J Drug Metab Pharmacokinet 2018; 43:737-750. [DOI: 10.1007/s13318-018-0485-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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10
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Comparison of metabolic pathways of different α-N-heterocyclic thiosemicarbazones. Anal Bioanal Chem 2018; 410:2343-2361. [PMID: 29476231 PMCID: PMC5849672 DOI: 10.1007/s00216-018-0889-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Revised: 12/20/2017] [Accepted: 01/16/2018] [Indexed: 12/16/2022]
Abstract
Clinical failure of novel drugs is often related to their rapid metabolism and excretion. This highlights the importance of elucidation of their pharmacokinetic profile already at the preclinical stage of drug development. Triapine, the most prominent representative of α-N-heterocyclic thiosemicarbazones, was investigated in more than 30 clinical phase I/II trials, but the results against solid tumors were disappointing. Recent investigations from our group suggested that this is, at least partially, based on the fast metabolism and excretion. In order to establish more detailed structure/activity/metabolism relationships, herein a panel of 10 different Triapine derivatives was investigated for their metabolic pathways. From the biological point of view, the panel consists of terminally dimethylated thiosemicarbazones with nanomolar IC50 values, derivatives with micromolar cytotoxicities comparable to Triapine and a completely inactive representative. To study the oxidative metabolism, a purely instrumental approach based on electrochemistry/mass spectrometry was applied and the results were compared to the data obtained from microsomal incubations. Overall, the investigated thiosemicarbazones underwent the phase I metabolic reactions dehydrogenation, hydroxylation, oxidative desulfuration (to semicarbazone and amidrazone) and demethylation. Notably, dehydrogenation resulted in a ring-closure reaction with formation of thiadiazoles. Although strong differences between the metabolic pathways of the different thiosemicarbazones were observed, they could not be directly correlated to their cytotoxicities. Finally, the metabolic pathways for the most cytotoxic compound were elucidated also in tissues collected from drug-treated mice, confirming the data obtained by electrochemical oxidation and microsomes. In addition, the in vivo experiments revealed a very fast metabolism and excretion of the compound. Structure/activity/metabolisation relationships for 10 anticancer thiosemicarbazones were established using electrochemical oxidation coupled to mass spectrometry (EC-MS) and human liver microsomes analyzed by LC-MS ![]()
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11
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Mekonnen TF, Panne U, Koch M. Prediction of biotransformation products of the fungicide fluopyram by electrochemistry coupled online to liquid chromatography-mass spectrometry and comparison with in vitro microsomal assays. Anal Bioanal Chem 2018; 410:2607-2617. [PMID: 29455286 DOI: 10.1007/s00216-018-0933-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2017] [Revised: 01/22/2018] [Accepted: 01/31/2018] [Indexed: 12/22/2022]
Abstract
Biotransformation processes of fluopyram (FLP), a new succinate dehydrogenase inhibitor (SDHI) fungicide, were investigated by electrochemistry (EC) coupled online to liquid chromatography (LC) and electrospray mass spectrometry (ESI-MS). Oxidative phase I metabolite production was achieved using an electrochemical flow-through cell equipped with a boron-doped diamond (BDD) electrode. Structural elucidation and prediction of oxidative metabolism pathways were assured by retention time, isotopic patterns, fragmentation, and accurate mass measurements using EC/LC/MS, LC-MS/MS, and/or high-resolution mass spectrometry (HRMS). The results obtained by EC were compared with conventional in vitro studies by incubating FLP with rat and human liver microsomes (RLM, HLM). Known phase I metabolites of FLP (benzamide, benzoic acid, 7-hydroxyl, 8-hydroxyl, 7,8-dihydroxyl FLP, lactam FLP, pyridyl acetic acid, and Z/E-olefin FLP) were successfully simulated by EC/LC/MS. New metabolites including an imide, hydroxyl lactam, and 7-hydroxyl pyridyl acetic acid oxidative metabolites were predicted for the first time in our study using EC/LC/MS and liver microsomes. We found oxidation by dechlorination to be one of the major metabolism mechanisms of FLP. Thus, our results revealed that EC/LC/MS-based metabolic elucidation was more advantageous on time and cost of analysis and enabled matrix-free detection with valuable information about the mechanisms and intermediates of metabolism processes. Graphical abstract Oxidative metabolism of fluopyram.
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Affiliation(s)
- Tessema F Mekonnen
- Bundesanstalt für Materialforschung und -prüfung (BAM), Richard-Willstätter Str. 11, 12489, Berlin, Germany.,School of Analytical Sciences Adlershof (SALSA), Humboldt-Universität zu Berlin, Albert-Einstein-Str. 5-9, 12489, Berlin, Germany
| | - Ulrich Panne
- Bundesanstalt für Materialforschung und -prüfung (BAM), Richard-Willstätter Str. 11, 12489, Berlin, Germany.,School of Analytical Sciences Adlershof (SALSA), Humboldt-Universität zu Berlin, Albert-Einstein-Str. 5-9, 12489, Berlin, Germany
| | - Matthias Koch
- Bundesanstalt für Materialforschung und -prüfung (BAM), Richard-Willstätter Str. 11, 12489, Berlin, Germany.
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12
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Voltammetric and electrogeneration approaches for the assessment of the oxidative drug metabolism. Anal Bioanal Chem 2018; 410:2229-2239. [DOI: 10.1007/s00216-018-0897-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Revised: 01/12/2018] [Accepted: 01/16/2018] [Indexed: 12/26/2022]
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13
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Portychová L, Schug KA. Instrumentation and applications of electrochemistry coupled to mass spectrometry for studying xenobiotic metabolism: A review. Anal Chim Acta 2017; 993:1-21. [PMID: 29078951 DOI: 10.1016/j.aca.2017.08.050] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Revised: 08/21/2017] [Accepted: 08/26/2017] [Indexed: 01/03/2023]
Abstract
The knowledge of metabolic pathways and biotransformation of xenobiotics, artificial substances foreign to the entire biological system, is crucial for elucidation of degradation routes of potentially toxic substances. Nowadays, there are many methods to simulate xenobiotic metabolism in the human body in vitro. In this review, the metabolism of various substances in the human body is described, followed by a summary of methods used for prediction of metabolic pathways and biotransformation. Above all, focus is placed on the coupling of electrochemistry to mass spectrometry, which is still a relatively new technique. This promising tool can mimic both oxidative phase I and conjugative phase II metabolism. Different experimental arrangements, with or without a separation step, and various applications of this technique are illustrated and critically reviewed.
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Affiliation(s)
- Lenka Portychová
- Research Institute for Organic Synthesis, Inc., 533 54 Rybitví, Czech Republic; Department of Analytical Chemistry, Palacký University, 771 46 Olomouc, Czech Republic
| | - Kevin A Schug
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, TX 76019, USA.
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14
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Li J, Liu Y, Kim E, March JC, Bentley WE, Payne GF. Electrochemical reverse engineering: A systems-level tool to probe the redox-based molecular communication of biology. Free Radic Biol Med 2017; 105:110-131. [PMID: 28040473 DOI: 10.1016/j.freeradbiomed.2016.12.029] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Revised: 12/06/2016] [Accepted: 12/20/2016] [Indexed: 12/20/2022]
Abstract
The intestine is the site of digestion and forms a critical interface between the host and the outside world. This interface is composed of host epithelium and a complex microbiota which is "connected" through an extensive web of chemical and biological interactions that determine the balance between health and disease for the host. This biology and the associated chemical dialogues occur within a context of a steep oxygen gradient that provides the driving force for a variety of reduction and oxidation (redox) reactions. While some redox couples (e.g., catecholics) can spontaneously exchange electrons, many others are kinetically "insulated" (e.g., biothiols) allowing the biology to set and control their redox states far from equilibrium. It is well known that within cells, such non-equilibrated redox couples are poised to transfer electrons to perform reactions essential to immune defense (e.g., transfer from NADH to O2 for reactive oxygen species, ROS, generation) and protection from such oxidative stresses (e.g., glutathione-based reduction of ROS). More recently, it has been recognized that some of these redox-active species (e.g., H2O2) cross membranes and diffuse into the extracellular environment including lumen to transmit redox information that is received by atomically-specific receptors (e.g., cysteine-based sulfur switches) that regulate biological functions. Thus, redox has emerged as an important modality in the chemical signaling that occurs in the intestine and there have been emerging efforts to develop the experimental tools needed to probe this modality. We suggest that electrochemistry provides a unique tool to experimentally probe redox interactions at a systems level. Importantly, electrochemistry offers the potential to enlist the extensive theories established in signal processing in an effort to "reverse engineer" the molecular communication occurring in this complex biological system. Here, we review our efforts to develop this electrochemical tool for in vitro redox-probing.
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Affiliation(s)
- Jinyang Li
- Fischell Department of Bioengineering, University of Maryland, College Park, MD, USA; Institute for Bioscience and Biotechnology Research, University of Maryland, College Park, MD, USA
| | - Yi Liu
- Fischell Department of Bioengineering, University of Maryland, College Park, MD, USA; Institute for Bioscience and Biotechnology Research, University of Maryland, College Park, MD, USA
| | - Eunkyoung Kim
- Fischell Department of Bioengineering, University of Maryland, College Park, MD, USA; Institute for Bioscience and Biotechnology Research, University of Maryland, College Park, MD, USA
| | - John C March
- Department of Biological and Environmental Engineering, Cornell University, Ithaca, NY, USA
| | - William E Bentley
- Fischell Department of Bioengineering, University of Maryland, College Park, MD, USA; Institute for Bioscience and Biotechnology Research, University of Maryland, College Park, MD, USA
| | - Gregory F Payne
- Fischell Department of Bioengineering, University of Maryland, College Park, MD, USA; Institute for Bioscience and Biotechnology Research, University of Maryland, College Park, MD, USA.
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15
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Saurina J, Sentellas S. Strategies for metabolite profiling based on liquid chromatography. J Chromatogr B Analyt Technol Biomed Life Sci 2017; 1044-1045:103-111. [DOI: 10.1016/j.jchromb.2017.01.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Revised: 12/17/2016] [Accepted: 01/08/2017] [Indexed: 02/06/2023]
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16
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Ruokolainen M, Gul T, Permentier H, Sikanen T, Kostiainen R, Kotiaho T. Comparison of TiO2 photocatalysis, electrochemically assisted Fenton reaction and direct electrochemistry for simulation of phase I metabolism reactions of drugs. Eur J Pharm Sci 2015; 83:36-44. [PMID: 26690045 DOI: 10.1016/j.ejps.2015.12.012] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Revised: 12/03/2015] [Accepted: 12/08/2015] [Indexed: 01/23/2023]
Abstract
The feasibility of titanium dioxide (TiO2) photocatalysis, electrochemically assisted Fenton reaction (EC-Fenton) and direct electrochemical oxidation (EC) for simulation of phase I metabolism of drugs was studied by comparing the reaction products of buspirone, promazine, testosterone and 7-ethoxycoumarin with phase I metabolites of the same compounds produced in vitro by human liver microsomes (HLM). Reaction products were analysed by UHPLC-MS. TiO2 photocatalysis simulated the in vitro phase I metabolism in HLM more comprehensively than did EC-Fenton or EC. Even though TiO2 photocatalysis, EC-Fenton and EC do not allow comprehensive prediction of phase I metabolism, all three methods produce several important metabolites without the need for demanding purification steps to remove the biological matrix. Importantly, TiO2 photocatalysis produces aliphatic and aromatic hydroxylation products where direct EC fails. Furthermore, TiO2 photocatalysis is an extremely rapid, simple and inexpensive way to generate oxidation products in a clean matrix and the reaction can be simply initiated and quenched by switching the UV lamp on/off.
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Affiliation(s)
- Miina Ruokolainen
- Division of Pharmaceutical Chemistry and Technology, Faculty of Pharmacy, University of Helsinki, P.O. Box 56 (Viikinkaari 5E), FI-00014, Finland.
| | - Turan Gul
- Analytical Biochemistry, Department of Pharmacy, University of Groningen, A Deusinglaan 1, 9713 AV Groningen, The Netherlands.
| | - Hjalmar Permentier
- Analytical Biochemistry, Department of Pharmacy, University of Groningen, A Deusinglaan 1, 9713 AV Groningen, The Netherlands.
| | - Tiina Sikanen
- Division of Pharmaceutical Chemistry and Technology, Faculty of Pharmacy, University of Helsinki, P.O. Box 56 (Viikinkaari 5E), FI-00014, Finland.
| | - Risto Kostiainen
- Division of Pharmaceutical Chemistry and Technology, Faculty of Pharmacy, University of Helsinki, P.O. Box 56 (Viikinkaari 5E), FI-00014, Finland.
| | - Tapio Kotiaho
- Division of Pharmaceutical Chemistry and Technology, Faculty of Pharmacy, University of Helsinki, P.O. Box 56 (Viikinkaari 5E), FI-00014, Finland; Laboratory of Analytical Chemistry, Department of Chemistry, University of Helsinki, P.O. BOX 55 (A.I. Virtasen aukio 1), FI-00014, Finland.
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17
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Torres S, Brown R, Szucs R, Hawkins JM, Zelesky T, Scrivens G, Pettman A, Taylor MR. The application of electrochemistry to pharmaceutical stability testing — Comparison with in silico prediction and chemical forced degradation approaches. J Pharm Biomed Anal 2015; 115:487-501. [DOI: 10.1016/j.jpba.2015.08.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Revised: 08/03/2015] [Accepted: 08/09/2015] [Indexed: 10/23/2022]
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18
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Lu M, Liu Y, Helmy R, Martin GE, Dewald HD, Chen H. Online Investigation of Aqueous-Phase Electrochemical Reactions by Desorption Electrospray Ionization Mass Spectrometry. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2015; 26:1676-1685. [PMID: 26242804 DOI: 10.1007/s13361-015-1210-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Revised: 05/16/2015] [Accepted: 05/29/2015] [Indexed: 06/04/2023]
Abstract
Electrochemistry (EC) combined with mass spectrometry (MS) is a powerful tool for elucidation of electrochemical reaction mechanisms. However, direct online analysis of electrochemical reaction in aqueous phase was rarely explored. This paper presents the online investigation of several electrochemical reactions with biological relevance in the aqueous phase, such as nitrosothiol reduction, carbohydrate oxidation, and carbamazepine oxidation using desorption electrospray ionization mass spectrometry (DESI-MS). It was found that electroreduction of nitrosothiols [e.g., nitrosylated insulin B (13-23)] leads to free thiols by loss of NO, as confirmed by online MS analysis for the first time. The characteristic mass shift of 29 Da and the reduced intensity provide a quick way to identify nitrosylated species. Equally importantly, upon collision-induced dissociation (CID), the reduced peptide ion produces more fragment ions than its nitrosylated precursor ion (presumably the backbone fragmentation cannot compete with the facile NO loss for the precursor ion), thus facilitating peptide sequencing. In the case of saccharide oxidation, it was found that glucose undergoes electro-oxidation to produce gluconic acid at alkaline pH, but not at neutral and acidic pHs. Such a pH-dependent electrochemical behavior was also observed for disaccharides such as maltose and cellobiose. Upon electrochemical oxidation, carbamazepine was found to undergo ring contraction and amide bond cleavage, which parallels the oxidative metabolism observed for this drug in leucocytes. The mechanistic information of these redox reactions revealed by EC/DESI-MS would be of value in nitroso-proteome research and carbohydrate/drug metabolic studies.
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Affiliation(s)
- Mei Lu
- Center for Intelligent Chemical Instrumentation, Department of Chemistry and Biochemistry, Edison Biotechnology Institute, Ohio University, Athens, OH, 45701, USA
| | - Yong Liu
- Department of Process and Analytical Chemistry, Merck Research Laboratories, Merck and Co., Inc., Rahway, NJ, 07065, USA.
| | - Roy Helmy
- Department of Process and Analytical Chemistry, Merck Research Laboratories, Merck and Co., Inc., Rahway, NJ, 07065, USA
| | - Gary E Martin
- Department of Process and Analytical Chemistry, Merck Research Laboratories, Merck and Co., Inc., Rahway, NJ, 07065, USA
| | - Howard D Dewald
- Center for Intelligent Chemical Instrumentation, Department of Chemistry and Biochemistry, Edison Biotechnology Institute, Ohio University, Athens, OH, 45701, USA
| | - Hao Chen
- Center for Intelligent Chemical Instrumentation, Department of Chemistry and Biochemistry, Edison Biotechnology Institute, Ohio University, Athens, OH, 45701, USA.
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19
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Shi HL, Jia YW, Peng SL, Liao X, Ding LS, Liu YM. Metabolic study of Angelica dahurica extracts using a reusable liver microsomal nanobioreactor by liquid chromatography-mass spectrometry. Biomed Chromatogr 2015; 29:1514-1521. [PMID: 25753568 DOI: 10.1002/bmc.3451] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2014] [Revised: 12/18/2014] [Accepted: 01/19/2015] [Indexed: 12/18/2022]
Abstract
Highly active and recoverable nanobioreactors prepared by immobilizing rat liver microsomes on magnetic nanoparticles (LMMNPs) were utilized in metabolic study of Angelica dahurica extracts. Five metabolites were detected in the incubation solution of the extracts and LMMNPs, which were identified by means of HPLC-MS as trans-imperatorin hydroxylate (M1), cis-imperatorin hydroxylate (M2), imperatorin epoxide (M3), trans-isoimperatorin hydroxylate (M1') and cis-isoimperatorin hydroxylate (speculated M2'). Compared with the metabolisms of imperatorin and isoimperatorin, it was found that the five metabolites were all transformed from these two major compounds present in the plant. Since no study on isoimperatorin metabolism by liver microsomal enzyme system has been reported so far, its metabolites (M1' and M3') were isolated by preparative HPLC for structure elucidation by (1) H-NMR and MS(2) analysis. M3' was identified as isoimperatorin epoxide, which is a new compound as far as its chemical structure is concerned. However, interestingly, M3' was not detected in the metabolism of the whole plant extract. In addition, a study with known chemical inhibitors on individual isozymes of the microsomal enzyme family revealed that CYP1A2 is involved in metabolisms of both isoimperatorin and imperatorin, and CYP3A4 only in that of isoimperatorin.
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Affiliation(s)
- Hai-Li Shi
- Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yan-Wei Jia
- Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Shu-Lin Peng
- Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, China
| | - Xun Liao
- Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, China
| | - Li-Sheng Ding
- Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, China
| | - Yi-Ming Liu
- Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, China.,Department of Chemistry and Biochemistry, Jackson State University, 1400 Lynch St., Jackson, MS 39217, USA
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20
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Oberacher H, Pitterl F, Erb R, Plattner S. Mass spectrometric methods for monitoring redox processes in electrochemical cells. MASS SPECTROMETRY REVIEWS 2015; 34:64-92. [PMID: 24338642 PMCID: PMC4286209 DOI: 10.1002/mas.21409] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/28/2013] [Revised: 07/24/2013] [Accepted: 08/12/2013] [Indexed: 06/03/2023]
Abstract
Electrochemistry (EC) is a mature scientific discipline aimed to study the movement of electrons in an oxidation-reduction reaction. EC covers techniques that use a measurement of potential, charge, or current to determine the concentration or the chemical reactivity of analytes. The electrical signal is directly converted into chemical information. For in-depth characterization of complex electrochemical reactions involving the formation of diverse intermediates, products and byproducts, EC is usually combined with other analytical techniques, and particularly the hyphenation of EC with mass spectrometry (MS) has found broad applicability. The analysis of gases and volatile intermediates and products formed at electrode surfaces is enabled by differential electrochemical mass spectrometry (DEMS). In DEMS an electrochemical cell is sampled with a membrane interface for electron ionization (EI)-MS. The chemical space amenable to EC/MS (i.e., bioorganic molecules including proteins, peptides, nucleic acids, and drugs) was significantly increased by employing electrospray ionization (ESI)-MS. In the simplest setup, the EC of the ESI process is used to analytical advantage. A limitation of this approach is, however, its inability to precisely control the electrochemical potential at the emitter electrode. Thus, particularly for studying mechanistic aspects of electrochemical processes, the hyphenation of discrete electrochemical cells with ESI-MS was found to be more appropriate. The analytical power of EC/ESI-MS can further be increased by integrating liquid chromatography (LC) as an additional dimension of separation. Chromatographic separation was found to be particularly useful to reduce the complexity of the sample submitted either to the EC cell or to ESI-MS. Thus, both EC/LC/ESI-MS and LC/EC/ESI-MS are common.
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Affiliation(s)
- Herbert Oberacher
- Institute of Legal Medicine and Core Facility Metabolomics, Innsbruck Medical UniversityInnsbruck, Austria
| | - Florian Pitterl
- Institute of Legal Medicine and Core Facility Metabolomics, Innsbruck Medical UniversityInnsbruck, Austria
| | - Robert Erb
- Institute of Legal Medicine and Core Facility Metabolomics, Innsbruck Medical UniversityInnsbruck, Austria
| | - Sabine Plattner
- Institute of Legal Medicine and Core Facility Metabolomics, Innsbruck Medical UniversityInnsbruck, Austria
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21
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Bussy U, Boujtita M. Advances in the Electrochemical Simulation of Oxidation Reactions Mediated by Cytochrome P450. Chem Res Toxicol 2014; 27:1652-68. [DOI: 10.1021/tx5001943] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Ugo Bussy
- Department
of Fisheries and Wildlife, Michigan State University, Room 13 Natural
Resources Building, 480 Wilson Road, East Lansing, Michigan 48824, United States
| | - Mohammed Boujtita
- LUNAM Université de Nantes, CNRS, Chimie et Interdisciplinarité: Synthèse, Analyse et Modélisation (CEISAM), UMR 6230, 2 rue de la Houssinière, BP 92208, F-44322 Nantes cedex 3, France
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22
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Electrochemical simulation of phase I metabolism for 21 drugs using four different working electrodes in an automated screening setup with MS detection. Bioanalysis 2014; 6:2607-21. [DOI: 10.4155/bio.14.166] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Background: Electrochemical conversion of xenobiotics has been shown to mimic human phase I metabolism for a few compounds. Materials & methods: Twenty-one compounds were analyzed with a semiautomated electrochemical setup and mass spectrometry detection. Results: The system was able to mimic some metabolic pathways, such as oxygen gain, dealkylation and deiodination, but many of the expected and known metabolites were not produced. Conclusion: Electrochemical conversion is a useful approach for the preparative synthesis of some types of metabolites, but as a screening method for unknown phase I metabolites, the method is, in our opinion, inferior to incubation with human liver microsomes and in vivo experiments with laboratory animals, for example.
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23
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Faber H, Vogel M, Karst U. Electrochemistry/mass spectrometry as a tool in metabolism studies—A review. Anal Chim Acta 2014; 834:9-21. [DOI: 10.1016/j.aca.2014.05.017] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2014] [Revised: 04/28/2014] [Accepted: 05/12/2014] [Indexed: 10/25/2022]
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24
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Liu Y, Kim E, White IM, Bentley WE, Payne GF. Information processing through a bio-based redox capacitor: signatures for redox-cycling. Bioelectrochemistry 2014; 98:94-102. [PMID: 24769500 DOI: 10.1016/j.bioelechem.2014.03.012] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Revised: 03/27/2014] [Accepted: 03/28/2014] [Indexed: 11/15/2022]
Abstract
Redox-cycling compounds can significantly impact biological systems and can be responsible for activities that range from pathogen virulence and contaminant toxicities, to therapeutic drug mechanisms. Current methods to identify redox-cycling activities rely on the generation of reactive oxygen species (ROS), and employ enzymatic or chemical methods to detect ROS. Here, we couple the speed and sensitivity of electrochemistry with the molecular-electronic properties of a bio-based redox-capacitor to generate signatures of redox-cycling. The redox capacitor film is electrochemically-fabricated at the electrode surface and is composed of a polysaccharide hydrogel with grafted catechol moieties. This capacitor film is redox-active but non-conducting and can engage diffusible compounds in either oxidative or reductive redox-cycling. Using standard electrochemical mediators ferrocene dimethanol (Fc) and Ru(NH3)6Cl3 (Ru(3+)) as model redox-cyclers, we observed signal amplifications and rectifications that serve as signatures of redox-cycling. Three bio-relevant compounds were then probed for these signatures: (i) ascorbate, a redox-active compound that does not redox-cycle; (ii) pyocyanin, a virulence factor well-known for its reductive redox-cycling; and (iii) acetaminophen, an analgesic that oxidatively redox-cycles but also undergoes conjugation reactions. These studies demonstrate that the redox-capacitor can enlist the capabilities of electrochemistry to generate rapid and sensitive signatures of biologically-relevant chemical activities (i.e., redox-cycling).
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Affiliation(s)
- Yi Liu
- Institute for Bioscience and Biotechnology Research, University of Maryland, College Park, MD 20742, USA; Fischell Department of Bioengineering, University of Maryland, College Park, MD 20742, USA
| | - Eunkyoung Kim
- Institute for Bioscience and Biotechnology Research, University of Maryland, College Park, MD 20742, USA; Fischell Department of Bioengineering, University of Maryland, College Park, MD 20742, USA
| | - Ian M White
- Fischell Department of Bioengineering, University of Maryland, College Park, MD 20742, USA; Institute for Systems Research, University of Maryland, College Park, MD 20742, USA
| | - William E Bentley
- Institute for Bioscience and Biotechnology Research, University of Maryland, College Park, MD 20742, USA; Fischell Department of Bioengineering, University of Maryland, College Park, MD 20742, USA
| | - Gregory F Payne
- Institute for Bioscience and Biotechnology Research, University of Maryland, College Park, MD 20742, USA; Fischell Department of Bioengineering, University of Maryland, College Park, MD 20742, USA.
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25
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Faber H, Lutze H, Lareo PL, Frensemeier L, Vogel M, Schmidt TC, Karst U. Liquid chromatography/mass spectrometry to study oxidative degradation of environmentally relevant pharmaceuticals by electrochemistry and ozonation. J Chromatogr A 2014; 1343:152-9. [PMID: 24767796 DOI: 10.1016/j.chroma.2014.03.081] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2013] [Revised: 03/27/2014] [Accepted: 03/30/2014] [Indexed: 11/30/2022]
Abstract
In this work, the potential of electrochemical oxidation as a tool for the rapid prediction of transformation products in water appearing after ozonation is investigated. These two approaches were compared by choosing the two environmentally relevant model compounds diclofenac and metoprolol and comparison of their transformation products after electrochemical oxidation and treatment with ozone. Within these two approaches, certain similarities were observed in the resulting chromatograms: Six transformation products of the electrochemical oxidation of metoprolol were also detected in the ozone samples. For diclofenac two transformation products matched. Additionally, five of the electrochemically generated oxidation products were reported in literature to occur after water treatment processes. The application of a boron-doped diamond working electrode for electrochemical oxidation allowed the generation of hydroxyl radicals, which was shown by spin trapping experiments with p-chlorobenzoic acid. This allowed the generation of certain transformation products previously not obtained by electrochemical oxidation. Concluding, the hyphenation of electrochemistry with liquid chromatography and mass spectrometry offers a useful tool in transformation studies.
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Affiliation(s)
- Helene Faber
- Westfälische Wilhelms-Universität Münster, Institut für Anorganische und Analytische Chemie, Corrensstraße 30, 48149 Münster, Germany
| | - Holger Lutze
- Universität Duisburg-Essen, Instrumentelle Analytische Chemie, Universitätsstraße 4, 45141 Essen, Germany
| | - Pablo Lores Lareo
- Universität Duisburg-Essen, Instrumentelle Analytische Chemie, Universitätsstraße 4, 45141 Essen, Germany
| | - Lisa Frensemeier
- Westfälische Wilhelms-Universität Münster, Institut für Anorganische und Analytische Chemie, Corrensstraße 30, 48149 Münster, Germany
| | - Martin Vogel
- Westfälische Wilhelms-Universität Münster, Institut für Anorganische und Analytische Chemie, Corrensstraße 30, 48149 Münster, Germany
| | - Torsten C Schmidt
- Universität Duisburg-Essen, Instrumentelle Analytische Chemie, Universitätsstraße 4, 45141 Essen, Germany
| | - Uwe Karst
- Westfälische Wilhelms-Universität Münster, Institut für Anorganische und Analytische Chemie, Corrensstraße 30, 48149 Münster, Germany.
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26
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Emerging technologies for metabolite generation and structural diversification. Bioorg Med Chem Lett 2013; 23:5471-83. [DOI: 10.1016/j.bmcl.2013.08.003] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2013] [Revised: 08/02/2013] [Accepted: 08/03/2013] [Indexed: 11/18/2022]
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27
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Bussy U, Delaforge M, El-Bekkali C, Ferchaud-Roucher V, Krempf M, Tea I, Galland N, Jacquemin D, Boujtita M. Acebutolol and alprenolol metabolism predictions: comparative study of electrochemical and cytochrome P450-catalyzed reactions using liquid chromatography coupled to high-resolution mass spectrometry. Anal Bioanal Chem 2013; 405:6077-85. [DOI: 10.1007/s00216-013-7050-7] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2013] [Revised: 05/03/2013] [Accepted: 05/06/2013] [Indexed: 11/29/2022]
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28
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Influence of cimetidine and its metabolites on Cisplatin—Investigation of adduct formation by means of electrochemistry/liquid chromatography/electrospray mass spectrometry. J Chromatogr A 2013; 1279:49-57. [DOI: 10.1016/j.chroma.2012.12.069] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2012] [Revised: 12/03/2012] [Accepted: 12/24/2012] [Indexed: 11/17/2022]
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29
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Chen A, Tsao MJ, Chuang JF, Lin CH. Electrochemical determination of Verapamil with a microchip embedded with gold nanoelectrode ensemble electrodes. Electrochim Acta 2013. [DOI: 10.1016/j.electacta.2012.11.094] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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30
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Jahn S, Seiwert B, Kretzing S, Abraham G, Regenthal R, Karst U. Metabolic studies of the Amaryllidaceous alkaloids galantamine and lycorine based on electrochemical simulation in addition to in vivo and in vitro models. Anal Chim Acta 2012. [DOI: 10.1016/j.aca.2012.10.042] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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31
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Jahn S, Karst U. Electrochemistry coupled to (liquid chromatography/) mass spectrometry—Current state and future perspectives. J Chromatogr A 2012; 1259:16-49. [DOI: 10.1016/j.chroma.2012.05.066] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2012] [Revised: 05/09/2012] [Accepted: 05/19/2012] [Indexed: 02/04/2023]
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32
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Telgmann L, Faber H, Jahn S, Melles D, Simon H, Sperling M, Karst U. Identification and quantification of potential metabolites of Gd-based contrast agents by electrochemistry/separations/mass spectrometry. J Chromatogr A 2012; 1240:147-55. [DOI: 10.1016/j.chroma.2012.03.088] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2012] [Revised: 03/23/2012] [Accepted: 03/26/2012] [Indexed: 01/01/2023]
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